% Encoding: UTF-8 @COMMENT{BibTeX export based on data in FAU CRIS: https://cris.fau.de/} @COMMENT{For any questions please write to cris-support@fau.de} @inproceedings{faucris.114006464, abstract = {Two-dimensional time of fight and attenuation measurements offer unique opportunities in nondestructive ultrasound testing for defect detection. However, unavailability or costs for 2D matrix transducers usually require a mechanical scanning procedure with a single element transducer to acquire 2D projections. This time and cost intensive process is not applicable for high speed testing of e.g. low cost devices. We propose a concept of a crossed-array configuration for 2D transmission imaging in terms of time of fight and attenuation measurements. A mechanical setup and a data acquisition system have been developed to evaluate the potential of this concept. Our results show, that ultrasound crossed-array transmission imaging has a great potential in terms of time of fight and attenuation measurements for defect detection in non-destructive testing, e.g. for detection of delaminations. With an appropriate data acquisition system transmission images can be acquired with frames rates in the kHz range. Therefore, crossed-array transmission imaging is a unique, cost efficient procedure with a good resolution for high speed testing in industrial applications. © 2012 IEE}, author = {Koch, Andreas and Gruber, Stefan and Scharrer, Thomas and Fendt, Karl and Lerch, Reinhard and Ermert, Helmut}, booktitle = {2012 IEEE International Ultrasonics Symposium Proceedings}, date = {2012-10-07/2012-10-10}, doi = {10.1109/ULTSYM.2012.0010}, faupublication = {yes}, isbn = {9781467345613}, keywords = {2D projection; attenuation; crossed-array; speed of sound; time of fight; transmission imaging; ultrasound transmission}, pages = {36-39}, peerreviewed = {No}, title = {{2D} transmission imaging with a crossed-array configuration for defect detection}, venue = {Dresden}, year = {2012} } @inproceedings{faucris.122567544, author = {Volk, Adrian and Kaltenbacher, Manfred and Sutor, Alexander and Ertl, Michael and Lerch, Reinhard}, booktitle = {19th International Conference on the Computation of Electromagnetic Fields (Compumag 2013)}, faupublication = {yes}, keywords = {Electromagnetic measurements,Finite element methods,Magnetic anisotropy,Magnetostriction,Nonlinear magnetics,fem,magnetostriction}, peerreviewed = {unknown}, title = {{3D} {Anisotropic} {Model} for the {Numerical} {Computation} of {Nonlinear} {Magnetostriction}}, url = {http://www.compumag2013.com/}, year = {2013} } @inproceedings{faucris.110916564, author = {Koch, Andreas and Stiller, Florian and Lerch, Reinhard and Ermert, Helmut}, booktitle = {Ultrasonics Symposium (IUS), 2016 IEEE International}, doi = {10.1109/ULTSYM.2016.7728582}, faupublication = {yes}, pages = {1-4}, peerreviewed = {unknown}, title = {{3D}-pulse-echo-tomography for breast cancer and rheumatoid arthritis diagnosis - add-on-system and latest in-vivo-results}, year = {2016} } @article{faucris.210080868, author = {Wüst, Michael and Rupitsch, Stefan}, doi = {10.1002/adem.201800409}, faupublication = {yes}, journal = {Advanced Engineering Materials}, peerreviewed = {Yes}, title = {3-{D} {Scanning} {Acoustic} {Microscope} for {Investigation} of {Curved}-{Structured} {Smart} {Material} {Compounds}}, year = {2018} } @inproceedings{faucris.206184950, author = {Fink, Michael and George, Benedikt and Rupitsch, Stefan and Ermert, Helmut}, booktitle = {Proceedings of the Ultrasonics Symposium (IUS)}, date = {2018-10-22/2018-10-25}, doi = {10.1109/ultsym.2018.8579932}, faupublication = {yes}, peerreviewed = {unknown}, title = {{Accumulation} of {Magnetic} {Nanoparticles} {Employing} {High} {Intensity} {Focused} {Ultrasound} for {Drug} {Targeting} {Applications}}, venue = {Kobe}, year = {2018} } @article{faucris.120555644, author = {Hofer, M. and Jungwirth, Mario and Lerch, Reinhard and Weigel, Robert}, faupublication = {no}, journal = {Frequenz}, keywords = {Surface acoustic wave; Modeling}, note = {elib2cris::1512001600,hofer2001}, pages = {64-72}, peerreviewed = {Yes}, title = {{Accurate} and {Efficient} {Modeling} of {SAW} {Structures}}, volume = {55}, year = {2001} } @article{faucris.287463219, abstract = {Kahl et al., (2022) present a computational model of an autonomous agent implemented with an active self. With ideas based on the Free Energy Principle (Friston and Kiebel, 2009), their model tackles the challenge to unify higher-level cognitive activities and lower-level sensorimotor control as the autonomous agent maintains situational awareness while interacting with the environment. While Kahl et al., (2022) focus on modeling a single agent, we argue that this challenge similarly appears in modeling human–robot interaction (HRI). In this commentary, we discuss how the conceptual framework from Kahl et al., (2022) could inspire unified models of physical and cognitive HRI and how the modeling approach from Kahl et al., (2022) can potentially be applied to anticipatory thinking in robotics to support the human in daily life.}, author = {Hao, Chenxu and Russwinkel, Nele and Haeufle, Daniel F.B. and Beckerle, Philipp}, doi = {10.1016/j.cogsys.2022.12.006}, faupublication = {yes}, journal = {Cognitive Systems Research}, keywords = {Anticipatory thinking; Human–robot interaction; Unified models of HRI}, note = {CRIS-Team Scopus Importer:2023-01-13}, pages = {1-3}, peerreviewed = {Yes}, title = {{A} {Commentary} on {Towards} autonomous artificial agents with an active self: {Modeling} sense of control in situated action}, volume = {79}, year = {2023} } @inproceedings{faucris.122143164, abstract = {In Central Europe, acoustic monitoring of bat activity has become the most common method to assess the collision risk of bats at wind turbines. Often, acoustic data are used to develop turbine specific ‘bat friendly’ operational algorithms that reduce the collision risk. A major problem of acoustic monitoring is that there are many different methods (e.g. monitoring at the nacelle vs. at ground level, different microphone setups) and different devices (e.g. bat detectors) used to conduct such acoustic surveys at turbines. As these methods and systems vary in their acoustic properties, the bat activity measured strongly depends on the methods/devices used. Precise estimation of bat activity is crucial to assess the collision risk and to develop suitable algorithms to reduce the risk of bat collisions, but also to avoid needless shutdowns of turbines because of algorithms that are too conservative. Here, we compare different methods and detectors that are being used to assess the acoustic bat activity wind turbines, in particular maintenance requirements, downtimes, acoustic properties, and bat activity level recorded. We did acoustic surveys at the nacelle of 16 wind turbines in 8 wind parks in four geographical regions in Germany in 2012 using different systems simultaneously. We used Anabat SD1 (Titley Scientific), Batcorder 1.0 (ecoObs) and UltraSoundGate (Avisoft Bioacoustics) detectors. In the lab, we also measured the frequency responses and directional sensitivity of the detector microphones. We compared the acoustic activity of bats as presence/absence data for 10-minute-intervalls and found that with the settings we used the relative activity of species and species groups was quite similar for different detectors but for most species or species groups Anabat SD1 and UltraSoundGate recorded bat activity that was twice as high as the activity measured with the Batcorder. This shows that for different detectors different models have to be used to precisely predict risk of collision for the bats and deduce suitable algorithms. We found that the employment of different microphone types with different directional characteristics and the use of various detector settings (i.e. various detection thresholds) are one of the main reasons for different estimations of bat activity. We further discuss detection volumes of detectors deduced from frequency response measurements and methods for a consistent calibration.}, author = {Simon, Ralph and Brinkmann, Robert and Hochradel, Klaus and Mages, Jürgen and Nagy, Martina and Niermann, Ivo and Stiller, Florian and Behr, Oliver}, booktitle = {Conference on Wind energy and Wildlife Impacts}, faupublication = {yes}, peerreviewed = {unknown}, title = {{Acoustic} assessment of bat activity at wind turbines: {Comparing} the performance of different bat detectors}, venue = {Berlin}, year = {2015} } @article{faucris.117341664, abstract = {A reliable and objective evaluation of voice quality is of essential importance in the therapy of pathological voices. The cepstral peak prominence (CPP) is calculated in the cepstral domain and is insensitive to variations of the fundamental frequency or pitch-tracking errors. Owing to the inconsistent information about its calculation procedure in the literature, the quantitative comparison of CPP values is difficult. This study provides insight into different definitions for the cepstrum calculation and also parameter variations. Their influence on the resulting CPP is presented on the basis of an acoustic dataset of sustained phonation obtained from an ex vivo human larynx model. Applying the different definitions for cepstrum calculation, the absolute CPP values varied within six orders of magnitude. Variation of the window length for partitioning the acoustic time signal and use of the averaging method over the windows yielded both quantitative and qualitative deviations of the CPP distribution. The results showed that it is essential to provide detailed information about the CPP calculation procedure to permit quantitative comparisons with the literature. After its evaluation, the CPP was used to investigate the acoustic influence of the ventricular folds as a function of the sub-glottal pressure (P-sub). In the present study, the CPP definition of Hillenbrand et al. [1], which has become established in voice research, was applied. In vitro experiments with two excised human larynx models, each in the configuration with and without ventricular folds, were executed. The results were compared with those of available studies with canine larynges. The analysis turns out that the ventricular folds stabilise and enhance the acoustic output at low P-sub ranges at which the ventricular folds do not oscillate. After oscillation onset of the vocal folds, the CPP increases for increasing Psub and reaches its maximum at relatively low Path values. By further increasing Psub the CPP decreases much faster for the configuration with ventricular folds than without. This could be attributed to the movement of the ventricular folds. We suggest that the ventricular folds support and stabilise the vocal fold phonation process as far as they act as stationary boundary conditions. As soon as the glottal flow excites the ventricular folds to move periodically, the process is destabilised resulting in a decrease of voice quality, represented by lower CPP values.}, author = {Birk, Veronika and Sutor, Alexander and Döllinger, Michael and Bohr, Christopher and Kniesburges, Stefan}, doi = {10.3813/AAA.918941}, faupublication = {yes}, journal = {Acta Acustica United With Acustica}, pages = {244-256}, peerreviewed = {Yes}, title = {{Acoustic} {Impact} of {Ventricular} {Folds} on {Phonation} {Studied} in {Ex} {Vivo} {Human} {Larynx} {Models}}, volume = {102}, year = {2016} } @inproceedings{faucris.290026372, address = {NEW YORK}, author = {Chapman, Jayden and Dwivedi, Anany and Liarokapis, Minas}, booktitle = {2022 IEEE-RAS 21ST INTERNATIONAL CONFERENCE ON HUMANOID ROBOTS (HUMANOIDS)}, doi = {10.1109/humanoids53995.2022.10000237}, faupublication = {yes}, month = {Jan}, note = {CRIS-Team WoS Importer:2023-03-03}, pages = {337-343}, peerreviewed = {unknown}, publisher = {IEEE}, title = {{A} {Dexterous}, {Adaptive}, {Affordable}, {Humanlike} {Robot} {Hand}: {Towards} {Prostheses} with {Dexterous} {Manipulation} {Capabilities}}, venue = {Ginowan}, year = {2022} } @article{faucris.262661854, abstract = {Achieving efficient and human-like hopping motions with consistent consecutive patterns requires proper mechanical design and control. In this regard, we introduce a new bioinspired design and control approach comprised of a hybrid actuation system and force-based compliance control. Combining an electric motor with a pneumatic artificial muscle makes up the so-called Electric-Pneumatic Actuation (EPA) system which enables presetting the leg compliance. Using the ground reaction force for online adjustment of EPA allows controlling the leg stiffness. This approach combines a simplified version of reflex-based control and physical impedance adjustment, that resembles the human neuromuscular system in a parsimonious way. By optimizing PAM pressures and control gains for different targeted hopping heights using Bayesian optimization, we show experimentally that the proposed approach generates various stable hopping motions and yields efficient performance. Moreover, our method is shown to be capable of creating more human-like hopping patterns compared to the previous studies on the same robot.}, author = {Galljamov, Rustam and Ahmadi, Arjang and Mohseni, Omid and Seyfarth, Andre and Beckerle, Philipp and Sharbafi, Maziar A.}, doi = {10.1109/LRA.2021.3095024}, faupublication = {yes}, journal = {IEEE Robotics and Automation Letters}, keywords = {Biologically-inspired robots; compliance and impedance control; legged robots}, note = {CRIS-Team Scopus Importer:2021-08-13}, pages = {6797-6804}, peerreviewed = {Yes}, title = {{Adjustable} {Compliance} and {Force} {Feedback} as {Key} {Elements} for {Stable} and {Efficient} {Hopping}}, volume = {6}, year = {2021} } @inproceedings{faucris.117924004, abstract = {In this paper we present recent research regarding the influence of geometric variations on the flow and the generated noise. Our basic configuration has been a wall mounted square cylinder, which exhibits a tonal noise. This setup was modified by attaching different shaped bodies to the square cylinder. For each configuration we have performed detailed experimental and simulation based investigations. As a result, we can state, that the level of the total turbulent energy in the flow field behind the cylinder is not the dominant criteria for the estimation of the radiated acoustic pressure level. However, an important factor plays the anisotropy of the turbulence. © 2007 by Stefan Becker.}, author = {Becker, Stefan and Kaltenbacher, Manfred and Ali, Irfan and Hahn, Christian and Escobar Ramos, Max Eduardo and Kaltenhauser, Albert and Ulrich, Frank}, booktitle = {13th AIAA/CEAS Aeroacoustic Conference}, date = {2007-05-21/2007-05-23}, faupublication = {yes}, note = {UnivIS-Import:2015-04-16:Pub.2007.tech.ITC.stmmec.aeroac}, title = {{Aeroacoustic} investigation of the flow around cylinder geometries - a benchmark test case}, url = {http://www.scopus.com/record/display.url?eid=2-s2.0-78649594244&origin=resultslist&sort=plf-f&src=s&st1=Aeroacoustic+investigation+of+the+flow+around+cylinder+geometries+-+a+benchmark+test+case&sid=EEB3734FFB700C494B555AF90A2C8B58.I0QkgbIjGqqLQ4Nw7dqZ4A%3a490&sot=b&sdt=b&sl=109&s=TITLE-ABS-KEY-AUTH%28Aeroacoustic+investigation+of+the+flow+around+cylinder+geometries+-+a+benchmark+test+case%29&relpos=0&relpos=0&citeCnt=1&searchTerm=TITLE-ABS-KEY-AUTH%28Aeroacoustic+investigation+of+the+flow+around+cylinder+geometries+-+a+benchmark+test+case%29}, venue = {Rom, Italien}, year = {2007} } @inproceedings{faucris.114288064, abstract = {For various piezoceramic actuator applications, the active materials are exposed to mechanical bias stresses. Such mechanical loading strongly modifies the hysteretic transfer characteristic of the actuators. An appropriate approach to model the hysteretic characteristic is based on the Preisach operator. However, the classical Preisach model is incapable of reflecting the influence of mechanical loading. The scope of the present study is, thus, the development of a generalized Preisach model incorporating the impact of compressive stress. To accomplish this goal, the effects of stress and mechanical creep on the polarization hysteresis are characterized by means of measurements. For our model, we take advantage of an analytic Preisach distribution function, introduced in our recent work. This function is extended to a formulation incorporating uniaxial compressive bias stress. As the results clearly demonstrate, the utilized distribution function is very promising to be further extended with respect to mechanical creep behavior. (C) 2011 Elsevier B.V. All rights reserved.}, author = {Wolf, Felix and Sutor, Alexander and Rupitsch, Stefan and Lerch, Reinhard}, doi = {10.1016/j.sna.2011.12.031}, faupublication = {yes}, keywords = {Generalized Preisach model;Analytic weight function;Stress-dependent distribution function;Uniaxial prestress;Compressive stress;PZT;Piezoceramics;Ferroelectric hysteresis;Mechanical creep}, pages = {223-229}, peerreviewed = {unknown}, publisher = {Elsevier}, title = {{A} generalized {Preisach} approach for piezoceramic materials incorporating uniaxial compressive stress}, volume = {186}, year = {2012} } @article{faucris.304456193, abstract = {Human manual dexterity relies critically on touch. Robotic and prosthetic hands are much less dexterous and make little use of the many tactile sensors available. We propose a framework modeled on the hierarchical sensorimotor controllers of the nervous system to link sensing to action in human-in-the-loop, haptically enabled, artificial hands.}, author = {Seminara, Lucia and Dosen, Strahinja and Mastrogiovanni, Fulvio and Bianchi, Matteo and Watt, Simon and Beckerle, Philipp and Nanayakkara, Thrishantha and Drewing, Knut and Moscatelli, Alessandro and Klatzky, Roberta L. and Loeb, Gerald E.}, doi = {10.1126/scirobotics.add5434}, faupublication = {yes}, journal = {Science Robotics}, note = {CRIS-Team Scopus Importer:2023-06-02}, pages = {eadd5434-}, peerreviewed = {Yes}, title = {{A} hierarchical sensorimotor control framework for human-in-the-loop robotic hands}, volume = {8}, year = {2023} } @inproceedings{faucris.272555282, address = {NEW YORK}, author = {Denz, Robin and Demirci, Rabia and Cansev, Mehmet Ege and Bliek, Adna and Beckerle, Philipp and Rueckert, Elmar and Rottmann, Nils}, booktitle = {2021 20TH INTERNATIONAL CONFERENCE ON ADVANCED ROBOTICS (ICAR)}, doi = {10.1109/icar53236.2021.9659403}, faupublication = {yes}, month = {Jan}, note = {CRIS-Team WoS Importer:2022-04-08}, pages = {1109-1115}, peerreviewed = {unknown}, publisher = {IEEE}, title = {{A} high-accuracy, low-budget {Sensor} {Glove} for {Trajectory} {Model} {Learning}}, venue = {, ELECTR NETWORK}, year = {2021} } @inproceedings{faucris.112105004, author = {Gedeon, Dominik and Meyer, Simon and Rupitsch, Stefan and Lerch, Reinhard}, faupublication = {yes}, title = {{A} {Hybrid} {Simulation} {Approach} for {Piezoelectric} {Vibration} {Energy} {Harvesting}.}, year = {2015} } @inproceedings{faucris.122409584, author = {Lerch, Reinhard and Weigel, Robert}, booktitle = {48. Jahrestagung der Österreichischen Physikalischen Gesellschaft (ÖPG) - Fachtagung Akustik}, faupublication = {no}, note = {elib2cris::1512001600,lerch1998}, pages = {137}, peerreviewed = {unknown}, title = {{Akustik} im {Bereich} {Mechatronik} der {Universität} {Linz}}, venue = {Graz, Austria}, year = {1998} } @inproceedings{faucris.289685591, abstract = {Over the past decade, the use of virtual reality applications is increasing in the field of robotics, which is set to increase even further with the advent of “Metaverse”. Metaverse is considered as an “embodied internet” which will seamlessly integrate machines, robots, and computer applications including those in virtual and augmented reality. In this work, we review the current state of research and discuss the underlying problems with the current design and evaluation methods for the state-of-the-art virtual reality interfaces employed in the field of robotics. To overcome these issues, we present our perspective on the methods for design and evaluation of such interfaces. Our perspective takes into account human-centered design methods along with the functional measures of evaluating the performance of the interfaces. This interdisciplinary perspective emphasizes rigorously designed empirical experiments that require close collaborations among engineers, designers, human-computer interaction researchers and cognitive scientists.}, author = {Hao, Chenxu and Dwivedi, Anany and Beckerle, Philipp}, booktitle = {Springer Proceedings in Advanced Robotics}, date = {2022-09-22/2022-09-23}, doi = {10.1007/978-3-031-22731-8{\_}1}, editor = {Pablo Borja, Cosimo Della Santina, Luka Peternel, Elena Torta}, faupublication = {yes}, isbn = {9783031227301}, keywords = {Augmented reality; Human-machine interfaces; Human-robot interaction; Virtual reality}, note = {CRIS-Team Scopus Importer:2023-02-24}, pages = {1-13}, peerreviewed = {unknown}, publisher = {Springer Nature}, title = {{A} {Literature}-{Based} {Perspective} on {Human}-{Centered} {Design} and {Evaluation} of {Interfaces} for {Virtual} {Reality} in {Robotics}}, venue = {Delft, NLD}, volume = {26}, year = {2023} } @inproceedings{faucris.121864204, abstract = {Many behavioral studies demand knowledge of the distribution or location of bats in space. Our research group investigated the behavior of bats in close proximity to the nacelle of wind turbines. Therefore, we measured the distribution of bats with help of stereo infrared cameras. Systems able to provide this information are expensive, complicated and require a specialist in the field for assembly and data acquisition. Our aim was to design an inexpensive and easy to use system to localize bats that, in addition, allows long recording periods. In order to gain maximum information the localization system contains different sensor technologies. On one hand, it includes active infrared-stereo-cameras to localize bats optically and on the other hand each ultrasonic bat call can be recorded and localized by multilateration with multiple novel ultrasonic microphones. We developed a calibration procedure to align the optical and the acoustical system.
The developed setup with its dimension of 1x1m is tripod mountable and the costs sum up to 5000 EUR with the goal to decrease costs to 2000 EUR. To achieve this, we programmed a FPGA to record the ultrasonic bat signals to be independent of proprietary hardware. Furthermore, we implemented a novel detection algorithm for ultrasonic bat calls which allows to run different detection techniques simultaneously in real-time. This algorithm was optimized for the FPGA and provides precise distinction between bat calls and noise to reduce post processing efforts and disk space. Both systems offer an accuracy of ±20 cm within a radius of 20 m. Since the optical and the acoustical system are calibrated, their results can be combined to improve not only accuracy but also reliability.}, author = {Hochradel, Klaus and Dorsch, Philipp and Häcker, Timm and Hohler, Tino and Sutor, Alexander and Lerch, Reinhard}, booktitle = {International Bat Research Conference}, date = {2016-07-31/2016-08-05}, faupublication = {yes}, keywords = {Microphone Array; Bat; Localization; Stereo Camera}, peerreviewed = {unknown}, title = {{A} low cost - high accuracy multisensor array for bat localization}, venue = {Durban}, year = {2016} } @article{faucris.216888780, abstract = {This contribution deals with an advanced synthetic aperture focusing technique for acoustic microscopy, which enables an almost precise reconstruction of the reflectivity distribution of both fluid-like and solid specimen. The presented approach is designed for single-element ultrasonic immersion transducers as they are commonly used in scanning acoustic microscopes. In practice, the resulting images offer at least lateral and axial resolutions of a focused image, which was acquired by a transducer with double center frequency. Moreover, the results show very low side lobe levels and the approach reconstructs the shape of inner defects even in images with present multiple reflections. A comparison with the well-known delay-and-sum technique reveals that the introduced approach offers a significantly more precise reconstruction of the given reflectivity distribution, especially when a complex reflectivity distribution is investigated. The advanced synthetic aperture focusing technique is applied to a generic test samples and to a curved multi-layered compound specimen.}, author = {Wüst, Michael and Schwarz, Michael and Eisenhart, Johannes and Nierla, Michael and Rupitsch, Stefan}, doi = {10.1016/j.ndteint.2019.03.009}, faupublication = {yes}, journal = {Ndt & E International}, keywords = {2010 MSC: 00–01; 99–00; Acoustic microscopy; Numerical simulation; Smart material compounds; Synthetic aperture focusing techniques; Ultrasonic imaging}, note = {CRIS-Team Scopus Importer:2019-05-03}, pages = {51-57}, peerreviewed = {Yes}, title = {{A} matched model-based synthetic aperture focusing technique for acoustic microscopy}, volume = {104}, year = {2019} } @article{faucris.108458724, abstract = {This paper introduces a new measurement setup for extraction of the local magnetic properties. With the help of finite element method simulations, modifications are made on the previous double-C-yoke method. Small dimension measuring coils are applied in the stray field produced by the magnetic circuit to evaluate the local magnetic properties of the specified part of the specimen. Through the measurements with the plastically deformed materials at different temperatures, it indicates that the magnetic properties of soft magnetic materials are quite sensitive to plastic straining. After high-temperature thermal treatment on the plastically deformed specimen, the local magnetic properties exhibit an obvious recovery. (C) 2011 American Institute of Physics. [doi:10.1063/1.3535549]}, author = {Bi, Shasha and Sutor, Alexander and Lerch, Reinhard and Xiao, Yunshi}, doi = {10.1063/1.3535549}, faupublication = {yes}, journal = {Journal of Applied Physics}, peerreviewed = {Yes}, title = {{A} measurement setup for acquiring the local magnetic properties of plastically deformed soft magnetic materials}, volume = {109}, year = {2011} } @article{faucris.108552884, abstract = {In this contribution, we present and evaluate a method for characterizing stapes prostheses by their mechanical transfer function. The measurements were carried out after a stapedotomy surgery was performed in three human temporal bones conserved in 4% formaldehyde. The inner ear was drained of fluid. Successively, one of three different stapes prostheses was inserted. After such preparation, the prosthesis piston movement compared to the incus movement is measured with laser vibrometry. The magnitude transfer function considered is defined as the amplitude of the prosthesis piston movement compared to the amplitude of the incus movement. Measurements were made in a frequency range from 500 Hz to 4 kHz. The measured amplitudes roughly ranged between 10 nm and 100 nm. A great advantage of the presented method is the fact that only a small portion of the ossicular chain influences the measurement, mainly the joint between the prosthesis and the incus. Furthermore, the usage of cadaver temporal bones allows for an automated measurement setup, long term experiments and the access of measurement positions inapproachable during in vivo measurements. With this method, the different kinds of prostheses could be evaluated on incuses of different diameters. (C) 2012 IPEM. Published by Elsevier Ltd. All rights reserved.}, author = {Sutor, Alexander and Hornung, Joachim and Goßler, Julian and Döllinger, Michael and Lerch, Reinhard}, doi = {10.1016/j.medengphy.2012.02.001}, faupublication = {yes}, journal = {Medical Engineering & Physics}, keywords = {Otosclerosis;Stapes prosthesis;Crimping;Mechanical transfer function;Laser vibrometer}, pages = {659-663}, peerreviewed = {Yes}, title = {{A} method for characterizing stapes prostheses by their mechanical transfer function}, volume = {34}, year = {2012} } @inproceedings{faucris.117347824, author = {Sutor, Alexander and Heining, Martin and Lindenberger, Christoph and Buchholz, Rainer}, booktitle = {Proceedings of INTERMAG2014}, faupublication = {yes}, pages = {2202-2204}, peerreviewed = {unknown}, title = {{A} {Method} for {Optimizing} the {Field} {Coils} of {Internally} {Illuminated} {Photobioreactors}}, year = {2014} } @inproceedings{faucris.107039504, abstract = {This contribution is concerned with a technique to precisely measure the physical dimensions of flaws in solid specimen by pulse-echo mode acoustic microscopy. We have implemented a synthetic aperture focusing technique (SAFT), which is based on a semi-numerical simulation approach (SIRFEM). In acoustic microscopy, one normally applies single-element transducers with center frequencies above 10MHz. Due to the very short wavelengths, numerical simulations demand a very fine discretized measurement setup. This would lead to extensive calculation costs. Therefore, we model the sound propagation in the fluid coupling medium between transducer surface and specimen analytically by the spatial impulse response (SIR) method. Only the mechanical wave propagation in the solid specimen is then simulated by a higher-order finite element method (FEM). This coupled SIRFEM method can be used to calculate the RF signal output (i.e., echo data) of ultrasonic transducers. The presented model-based SAFT algorithm is based on an optimized filter-kernel, which is generated by an adapted SIRFEM simulation.}, author = {Wüst, Michael and Nierla, Michael and Rupitsch, Stefan}, booktitle = {Ultrasonics Symposium (IUS), 2016 IEEE International}, date = {2016-09-18/2016-09-21}, doi = {10.1109/ULTSYM.2016.7728458}, editor = {IEEE}, faupublication = {yes}, isbn = {978-1-4673-9897-8}, keywords = {ultrasound; non-destructive evaluation; numerical simulation; synthetic aperture focusing techniques;}, peerreviewed = {unknown}, title = {{A} model-based synthetic aperture focusing technique for acoustic microscopy}, venue = {Tours}, year = {2016} } @inproceedings{faucris.107813024, abstract = {In Europe, a widespread method to mitigate bat collisions at wind energy turbines is to stop the rotor during times with high collision rates. To do this efficiently, high collision rates need to be predicted in order to save bats from being killed. Also, periods with low collision risk have to be identified to minimize losses in energy production. We present a model that reliably predicts turbine specific collision rates as well as identifies times with low collision risk. The model is a hierarchical zero-inflated Poisson model that includes a Bernoulli model for collision risk and a Poisson model for the collision rate. We developed the model based on a large empirical data set including daily carcass searches at 30 turbines during 3 months, and continuous recordings of acoustic bat activity and wind speed at the nacelle of the turbine at 70 turbines during 7 months. We corrected for the imperfect detection of carcasses within the model. The model is particularly useful for predicting bat collision rates during times of the year with low bat activity and little empirical data on collision rates.}, author = {Korner-Nievergelt, Fränzi and Baumbauer, Lothar and Brinkmann, Robert and Hochradel, Klaus and Hurst, Johanna and Mages, Jürgen and Nagy, Martina and Niermann, Ivo and Reers, Hendrik and Simon, Ralph and Weber, Natalie and Behr, Oliver}, booktitle = {Conference on Wind energy and Wildlife Impacts}, faupublication = {no}, peerreviewed = {unknown}, title = {{A} model for the prediction of bat collision rates at wind energy turbines}, venue = {Berlin}, year = {2015} } @article{faucris.123089824, abstract = {In this paper, we present a model for temperature dependent hysteretic nonlinearities with nonlocal memories. This model can be applied to describe hysteretic material behavior. Common applications are ferromagnetic or magnetostrictive materials. Our model consists mainly of a Preisach operator with a continuous Preisach weight function. We choose a weight function which shows a strong correlation between the function's parameters and certain properties of the hysteresis curve. As a new approach, the weight function is written as a function of temperature. The model parameters are customized to a set of symmetric hysteresis curves. We verify our model for magnetic materials with differently shaped hysteresis curves, different temperatures and magnetic field amplitudes. (C) 2011 American Institute of Physics. [doi:10.1063/1.3562520]}, author = {Sutor, Alexander and Rupitsch, Stefan and Bi, Shasha and Lerch, Reinhard}, doi = {10.1063/1.3562520}, faupublication = {yes}, journal = {Journal of Applied Physics}, peerreviewed = {Yes}, title = {{A} modified {Preisach} hysteresis operator for the modeling of temperature dependent magnetic material behavior}, volume = {109}, year = {2011} } @inproceedings{faucris.117344084, author = {Wolf, Felix and Sutor, Alexander and Rupitsch, Stefan and Lerch, Reinhard}, booktitle = {8th International Workshop on Direct and Inverse Problems in Piezoelectricity - Book of Abstracts}, faupublication = {yes}, peerreviewed = {unknown}, title = {{A} modified scalar {Preisach} model with an analytic weight function for piezoceramic actuators}, year = {2012} } @inproceedings{faucris.313347154, author = {Hao, Chenxu and Halupczok, Colin and Ilg, Winfried and Haeufle, Daniel F. B. and Beckerle, Philipp and Russwinkel, Nele}, booktitle = {International Conference on Cognitive Modeling}, faupublication = {yes}, peerreviewed = {unknown}, title = {{An} {ACT}-{R} {Observer} {Model} for {Anticipatory} {Assistive} {Robots}}, year = {2023} } @article{faucris.114290484, abstract = {The magnetostrictive effect offers new possibilities to design actuators for microsystems (MEMS). Especially monomorph-bending-cantilever-type microactuators can be used for many interesting applications. These actuators are excited to bending movements under the influence of external magnetic fields We present calculation methods, the fabrication process, and the measuring technology to enable the design of microsystems based on these actuators. The focus of this study is on the analysis of the mechanical eigenfrequencies and the characteristic magnetostrictive curves. Based on the results, our calculation methods as well as the reproducibility of our fabrication process are verified. Linear sections of the characteristic curves can be found using the data obtained.}, author = {Albach, Thorsten and Sutor, Alexander and Lerch, Reinhard and Sutor, Alexander}, doi = {10.1524/teme.2010.0011}, faupublication = {yes}, journal = {Technisches Messen}, keywords = {MEMS;microactuator;magnetostriction}, month = {Jan}, pages = {67-73}, peerreviewed = {Yes}, title = {{Analysis} of {Magnetostrictive} {Microactuators}}, volume = {77}, year = {2010} } @inproceedings{faucris.123033944, author = {Bi, Shasha and Sutor, Alexander and Lerch, Reinhard}, booktitle = {Proceedings of IEEE Magnetics Summer School}, faupublication = {yes}, pages = {24}, peerreviewed = {unknown}, title = {{An} efficient inverted hysteresis model with modified switch operator and differentiable weight function}, year = {2013} } @article{faucris.114290704, abstract = {This paper proposes a different inverted hysteresis model with modification of the classic Preisach switch operator. By using this new switch operator, the inverted model remains the wiping out and congruency properties. It also guarantees the symmetry and total positiveness of weight function in the Preisach plane. According to the change pattern of H(B) branches, a differentiable weight function is introduced in the inverted model. The weight function performs with good continuity and symmetry. This makes it possible to implement the inverted model in numerical analysis without iterative procedure. The identification work is done by means of the measured major loops. Here the Newton method algorithm is applied to optimize the mean squared error (MSE) between the measured and simulated data. By this way, the limited number of parameters can be determined. The inverted model was verified for both soft and hard magnetic materials. Besides major hysteresis loops, minor loops and first-order reversal curves (FORCs) can also be simulated. By comparison, the simulation results produced by the inverted hysteresis model show good approximation to the measurement data.}, author = {Bi, Shasha and Sutor, Alexander and Lerch, Reinhard and Xiao, Yunshi}, doi = {10.1109/TMAG.2013.2244583}, faupublication = {yes}, journal = {IEEE Transactions on Magnetics}, keywords = {Differentiable weight function;finite element method;inverted hysteresis model;switch operator}, pages = {3175-3178}, peerreviewed = {Yes}, title = {{An} {Efficient} {Inverted} {Hysteresis} {Model} with {Modified} {Switch} {Operator} and {Differentiable} {Weight} {Function}}, volume = {49}, year = {2013} } @article{faucris.121077704, abstract = {The vectorial modeling of hysteresis phenomena is an important task with respect to precise numerical simulation of ferromagnetic materials. Many vector models are based on extended Preisach models. Approaches are known where the scalar Preisach models are defined in different space directions and the results are calculated by summation or integration. Within this approach, we suggest a Preisach model that uses only one Preisach plane, but an additional rotational plane. This rotational plane practically defines a direction for each Preisach element. Therefore, this operator can be evaluated in a very efficient way. (C) 2012 American Institute of Physics. [doi: 10.1063/1.3672069]}, author = {Sutor, Alexander and Kallwies, Jan and Lerch, Reinhard}, doi = {10.1063/1.3672069}, faupublication = {yes}, journal = {Journal of Applied Physics}, peerreviewed = {Yes}, title = {{An} efficient vector {Preisach} hysteresis model based on a novel rotational operator}, volume = {111}, year = {2012} } @inproceedings{faucris.227846262, author = {Fink, Michael and Rupitsch, Stefan and Lyer, Stefan and Alexiou, Christoph and Ermert, Helmut}, booktitle = {Proceedings IEEE IUS 2019}, date = {2019-10-06/2019-10-09}, doi = {10.1109/ultsym.2019.8925977}, faupublication = {yes}, peerreviewed = {unknown}, title = {{An} {Enhanced} {Magnetomotive} {Ultrasound} {Algorithm} to {Quantitatively} {Estimate} the {Concentration} of {Iron}-{Oxide} {Nanoparticles} in {Perfused} {Tissue} for {Magnetic} {Drug} {Targeting}}, venue = {Glasgow}, year = {2019} } @inproceedings{faucris.114291584, abstract = {Superposition of pulse-echo data (FASC: Full Angle Spatial Compounding) acquired from 360 degrees around an object in a water bath as imaging concept for an Ultrasound Computed Tomography (USCT) add-on system has already shown a great potential in 2D for in-vivo investigations (e. g. breast cancer imaging). However, providing a small number of images for parallel cross-sectional planes with enhanced image quality is not sufficient for diagnostics. Volume datasets (3D) are needed. For this purpose we further developed our USCT add-on system to automatically rotate a motorized array (3D probe) around the object of investigation. Full integration of external motor and ultrasound electronics control in a custom made program allows acquiring 3D radio-frequency (rf) datasets from 360 degrees within an appropriate data acquisition time for in-vivo investigations. With respect to breast cancer imaging this concept also enables imaging of thorax close tissue regions which cannot be achieved by 2D FASC. Furthermore, moldings of polyvinyl alcohol (PVA) hydrogel adapted to respective body parts (e. g. female breast) have been developed as new concept for coupling. These PVA hydrogel moldings have a great potential to replace water bath technique in USCT. The water bath technique is in general assumed to be critical for clinical environments. In this contribution we present FASC volume datasets of a tissue mimicking breast phantom investigated in a water bath as well as with PVA hydrogel moldings used for coupling. Results show a great potential for 3D FASC with a motorized array (3D probe) and for the coupling concept with PVA hydrogel moldings.}, author = {Koch, Andreas and Genser, Markus and Stiller, Florian and Lerch, Reinhard and Ermert, Helmut}, booktitle = {Ultrasonics Symposium (IUS), 2013 IEEE International}, doi = {10.1109/ULTSYM.2013.0169}, faupublication = {yes}, keywords = {Full Angle Spatial Compounding;3D imaging;3D compounding;breast imaging;breast coupling;breast cancer;rheumatoid arthritis;polyvinyl alcohol}, month = {Jan}, pages = {655-658}, peerreviewed = {Yes}, title = {{A} new {3D}-tomographic ultrasound imaging concept for breast cancer and rheumatoid arthritis diagnostics avoiding water bath techniques}, year = {2013} } @article{faucris.114284104, abstract = {The mechanical behavior of a car's side window and the resulting acoustic radiation into the cabin is mainly affected by the spatial coherence of the surface pressure exciting the glass plate. The surface pressure is a superposition of hydrodynamic and acoustic pressure whose levels differ by 2 or 3 orders of magnitude. To gain information about the coherence characteristics of the surface pressure and to separate its hydrodynamic and acoustic components, a measurement of high spatial resolution is needed. For that reason a novel pressure transducer array with a minimum distance between two adjacent measurement points of only 2 mm was developed. The pressure transducers of the array are arranged sparsely on a grid while all possible distances between the spots on the grid are covered. Due to this minimization of distance redundancy, the amount of microphones could be reduced from 1849 to 92 representing a virtual array of 43 x 43 measurement positions. A Nyquist wavenumber of 250 1/m and a resolution of 11.9 1/m using a sensor area of only 52 x 52 mm(2) were achieved. Because of its small dimensions, this array allows for measurements at various test areas on the side window, which is a major improvement compared to former investigations. For the measurements conventional MEMS microphones are applied. It is shown that the used microphones are suitable for the requisite, even if operating in saturation. Hence, the existence of acoustic loads on the side window and the position-dependent spatial coherence of the surface pressure can be studied. Measurements using the sensor array are carried out in the anechoic wind tunnel to validate the methodology. Results of the separation between hydrodynamic and acoustic pressure as well as the identification of coherence properties are presented. (C) 2013 Elsevier Ltd. All rights reserved.}, author = {Gabriel, Christoph and Müller, Stefan and Ullrich, F. and Lerch, Reinhard}, doi = {10.1016/j.jsv.2013.09.045}, faupublication = {yes}, journal = {Journal of Sound and Vibration}, pages = {901-915}, peerreviewed = {Yes}, title = {{A} new kind of sensor array for measuring spatial coherence of surface pressure on a car's side window}, volume = {333}, year = {2014} } @inproceedings{faucris.110144144, author = {Gedeon, Dominik and Rupitsch, Stefan}, booktitle = {Proceedings Sensor 2017}, date = {2017-05-30/2017-06-01}, doi = {10.5162/sensor2017/D7.1}, editor = {AMA}, faupublication = {yes}, isbn = {978-3-9816876-4-4}, pages = {530 - 534}, peerreviewed = {unknown}, title = {{An} {Experimental} {Setup} for {Piezoelectric} {Cantilevered} {Vibration} {Energy} {Harvesters} on a {Rotating} {Drive} {Shaft}}, venue = {Nürnberg}, year = {2017} } @inproceedings{faucris.106389404, author = {Bi, Shasha and Wolf, Felix and Lerch, Reinhard and Sutor, Alexander}, booktitle = {Proceedings of INTERMAG2014}, faupublication = {yes}, pages = {1462-1463}, peerreviewed = {unknown}, title = {{An} {Inverted} {Preisach} {Model} with {Analytical} {Weight} {Function} and its {Numerical} {Discrete} {Formulation}}, year = {2014} } @article{faucris.121497464, abstract = {This paper proposes a numerical discrete formulation for an inverted hysteresis model, which is based on the classic Preisach model, but applies an inverted switch operator. The inverted switch operator is modified from the switch operator of the classic Preisach model. By applying this inverted switch operator, the inverted model retains the wiping-out and congruency properties. The distribution of the weight function can be approximated with an analytical function. By means of a quasi-Newton method algorithm, the small number of parameters in this function can be directly determined from major loops. Iterative procedure is circumvented in the implementation of this model in finite-element analysis. The simulated hysteresis loops, such as minor loops and reversal curves, show good agreement to the measurement data. To realize efficient numerical calculation, the integral expression of the inverted model is rewritten in a discrete form. The double integration of the weight function is numerically approximated in the precalculation stage. In this way, it costs low memory usage and short calculation time during the calculation procedure.}, author = {Bi, Shasha and Wolf, Felix and Lerch, Reinhard and Sutor, Alexander}, doi = {10.1109/TMAG.2014.2329836}, faupublication = {yes}, journal = {IEEE Transactions on Magnetics}, keywords = {Analytical weight function;finite-element (FE) method;inverted hysteresis model;numerical discrete formulation}, peerreviewed = {Yes}, title = {{An} {Inverted} {Preisach} {Model} {With} {Analytical} {Weight} {Function} and {Its} {Numerical} {Discrete} {Formulation}}, volume = {50}, year = {2014} } @inproceedings{faucris.229248882, abstract = {This contribution presents a novel approach to reduce electromagnetic interference of switched-mode power supplies. The interference reduction is based on the inverse piezoelectric effect. Providing a low-impedance propagation path for conducted emissions at a resonance frequency of a piezoelectric element, we can attenuate a discrete disturbance peak of a disturbance spectrum. We successfully integrated our novel piezoelectric EMI-filter in a flyback-converter in order to suppress a common-mode disturbance peak. Measurement results reveal that the suppression effect can be improved by 31 dB compared to a similar regular interference-suppression capacitor. Regarding the practical use of the developed piezoelectric EMI-filter, the temperature dependence is examined in additio}, author = {Hubert, Florian and Dorsch, Philipp and Rupitsch, Stefan and Dürbaum, Thomas}, booktitle = {PCIM Europe 2019; International Exhibition and Conference for Power Electronics, Intelligent Motion, Renewable Energy and Energy Management}, date = {2019-05-07/2019-05-09}, editor = {VDE VERLAG GMBH, Berlin · Offenbach}, faupublication = {yes}, isbn = {978-3-8007-4938-6}, pages = {630 - 637}, peerreviewed = {unknown}, publisher = {VDE VERLAG GMBH · Berlin · Offenbach}, title = {{A} {Novel} {Approach} to {Reduce} {EMI} in {Switched}-{Mode} {Power} {Supplies} {Operating} at {Fixed} {Switching} {Frequencies}}, venue = {Nuremberg, Germany}, year = {2019} } @inproceedings{faucris.123125024, address = {Linz}, author = {Gedeon, Dominik and Rupitsch, Stefan and Lerch, Reinhard and Luegmair, Georg and Döllinger, Michael}, booktitle = {Mechatronics 2012 - The 13th Mechatronics Forum International Conference}, editor = {R. Scheidl and B. Jakoby}, faupublication = {yes}, isbn = {978-3-99033-042-5}, pages = {135-141}, peerreviewed = {Yes}, publisher = {Trauner}, title = {{A} {Novel} {Setup} for the {Controlled} {Adduction} of {Vocal} {Folds}}, venue = {Linz}, year = {2012} } @inproceedings{faucris.305253131, abstract = {This contribution presents a novel approach for a temperature compensated DC magnetic field sensor, based on the magnetoelectric effect. In utilizing two vibration modes of a rectangular cuboid magnetoelectric sample, we can determine the samples’ temperature in addition to the magnetic flux density the sample is exposed t}, author = {Wich, Manfred and Hubert, Florian and Helmerich, Jan and Rupitsch, Stefan Johann}, booktitle = {SMSI 2023}, date = {2023-05-08/2023-05-11}, doi = {10.5162/SMSI2023/P60}, editor = {AMA Service GmbH}, faupublication = {no}, isbn = {978-3-9819376-8-8}, keywords = {Magnetoelectric, resonant magnetic field sensor, temperature compensation, delta-E effect, electromechanical vibration modes}, pages = {396-397}, peerreviewed = {Yes}, title = {{A} {Novel} {Temperature} {Compensated} {Magnetic} {Field} {Sensor} {Based} on the {Magnetoelectric} {Effect}}, url = {https://www.ama-science.org/proceedings/details/4506}, venue = {Nürnberg}, year = {2023} } @inproceedings{faucris.106623704, abstract = {This paper describes an ultrasonic sensor system for application in air that is capable of recognizing workpieces with size up to 20 mm, independently of their position and orientation, with high reliability. The 4x4 Transducer Matrix signals are first processed with a simplified reconstruction algorithm that leads to position invariant axial profiles of the object reflectivity. A broadband holographic reconstruction is then performed for those object planes that are reflecting the main signal energy. The Zernike Moments of the resulting cross-sectional patterns and features of the reflectivity profiles are fed in a 3-layered perceptron network. The system has been tested with a set of measuring data from 25 typical workpieces. Even though some objects have very similar reflection properties, it is possible to identify the objects in an area of 25x25 mm2 independently of their position and orientation with a recognition rate higher than 99%.}, address = {Piscataway, NJ, United States}, author = {Vossiek, Martin and Magori, V. and Ermert, Helmut}, booktitle = {IEEE International Ultrasonics Symposium}, date = {1994-11-01/1994-11-04}, doi = {10.1109/ULTSYM.1994.401820}, faupublication = {yes}, note = {UnivIS-Import:2017-12-18:Pub.1994.tech.IE.LEH.anultr}, pages = {1293-1297}, peerreviewed = {Yes}, publisher = {IEEE}, title = {{An} {Ultrasonic} {Multielement} {Sensor} {System} for {Position} {Invariant} {Object} {Identification}}, venue = {Cannes, France}, volume = {2}, year = {1994} } @inproceedings{faucris.119705564, author = {Vossiek, Martin and Magori, V. and Ermert, Helmut}, booktitle = {7. Internationale Fachmesse mit Kongreß für Sensoren, Meßaufnehmer & Systeme, Sensor 95}, faupublication = {yes}, note = {UnivIS-Import:2017-12-18:Pub.1995.tech.IE.LEH.anultr}, pages = {505-510}, peerreviewed = {unknown}, title = {{An} ultrasonic sensor system for location gauging and recognition of small workpieces. {Ein} {Ultraschall}-{Sensorsystem} zur {Erfassung} und {Erkennung} kleiner {Werkstücke}.}, venue = {Nürnberg}, year = {1995} } @article{faucris.108412744, abstract = {Full-angle spatial compounding (FASC) is a concept for pulse-echo imaging using an ultrasound tomography (UST) system. With FASC, resolution is increased and speckles are suppressed by averaging pulse-echo data from 360 degrees. In vivo investigations have already shown a great potential for 2-D FASC in the female breast as well as for finger-joint imaging. However, providing a small number of images of parallel cross-sectional planes with enhanced image quality is not sufficient for diagnosis. Therefore, volume data (3-D) is needed. For this purpose, we further developed our UST add-on system to automatically rotate a motorized array (3-D probe) around the object of investigation. Full integration of external motor and ultrasound electronics control in a custom-made program allows acquisition of 3-D pulse-echo RF datasets within 10 min. In case of breast cancer imaging, this concept also enables imaging of near-thorax tissue regions which cannot be achieved by 2-D FASC. Furthermore, moldings made of polyvinyl alcohol hydrogel (PVA-H) have been developed as a new acoustic coupling concept. It has a great potential to replace the water bath technique in UST, which is a critical concept with respect to clinical investigations. In this contribution, we present in vivo results for 3-D FASC applied to imaging a female breast which has been placed in a PVA-H molding during data acquisition. An algorithm is described to compensate time-of-flight and consider refraction at the water-PVA-H molding and molding-tissue interfaces. Therefore, the mean speed of sound (SOS) for the breast tissue is estimated with an image-based method. Our results show that the PVA-H molding concept is applicable and feasible and delivers good results. 3-D FASC is superior to 2-D FASC and provides 3-D volume data at increased image quality.}, author = {Koch, Andreas and Stiller, Florian and Lerch, Reinhard and Ermert, Helmut}, doi = {10.1109/TUFFC.2014.006494}, faupublication = {yes}, journal = {IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control}, pages = {266-279}, peerreviewed = {Yes}, title = {{An} {Ultrasound} {Tomography} {System} {With} {Polyvinyl} {Alcohol} ({PVA}) {Moldings} for {Coupling}: {In} {Vivo} {Results} for 3-{D} {Pulse}-{Echo} {Imaging} of the {Female} {Breast}}, volume = {62}, year = {2015} } @article{faucris.114294444, abstract = {This paper describes an optical measurement technique, referred to as light refractive tomography (LRT), which enables noninvasive measurement of ultrasound pressure fields in water. The pressure field arising from a cylindrically focused ultrasound transducer is measured separately by means of LRT and hydrophone. Good agreement is achieved between the results obtained by these two different methods. After that, LRT is extended and applied to the reconstruction of density variations in a PMMA block induced by ultrasound. The results appear plausible, however, a quantitative verification is currently still missing, since we know of no other published methods succeeding so far in the measurement of density change in solids induced by ultrasound.}, author = {Chen, Lizhuo and Rupitsch, Stefan and Lerch, Reinhard}, doi = {10.1524/teme.2012.0257}, faupublication = {yes}, journal = {Technisches Messen}, keywords = {Light refractive tomography;sound pressure;density change}, month = {Jan}, pages = {459-463}, peerreviewed = {Yes}, title = {{Application} of {Light} {Refractive} {Tomography} for {Reconstructing} {Ultrasound} {Fields} in {Various} {Media}}, volume = {79}, year = {2012} } @article{faucris.114295324, abstract = {In this paper we present a model for hysteretic nonlinearities with non-local memories. This model can be applied to describe hysteretic material behavior. Common applications are ferromagnetic or ferroelectric materials. Our model consists of an analytic function and a Preisach operator. We define a continuous Preisach weight function and introduce a method for the identification of the model parameters. The model parameters are customized to a set of symmetric hysteresis curves. We verify our model for a soft magnetic material, a hard magnetic material and the ferroelectric behavior of some piezoelectric material. After that, non-symmetric curves like the virgin curve are predicted very well by the model. It is especially useful, if forced magnetization or polarization, that appears beyond technical saturation, come into account.}, author = {Sutor, Alexander and Rupitsch, Stefan and Lerch, Reinhard}, doi = {10.1007/s00339-010-5884-9}, faupublication = {yes}, journal = {Applied Physics A-Materials Science & Processing}, pages = {425-430}, peerreviewed = {Yes}, title = {{A} {Preisach}-based hysteresis model for magnetic and ferroelectric hysteresis}, volume = {100}, year = {2010} } @article{faucris.114295984, abstract = {In this contribution, a numerically simulated ultrasound pressure field is exploited to determine the experimental parameters and to analyze the error sources as well as their influences on final results. After that, several ultrasound transducers excited with 1 MHz signals are investigated. The light refractive tomography results show good agreement with hydrophone measurements. Finally, we reconstruct 2000 transient states of the ultrasound pressure field within a volume of about 38 cm(3) after sending the burst signal. Without applying any smoothing to the resulting images, the reconstructed pressure field varies continuously in both spatial and temporal dimensions.}, author = {Chen, Lizhuo and Rupitsch, Stefan and Lerch, Reinhard}, doi = {10.1109/TUFFC.2012.2276}, faupublication = {yes}, journal = {IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control}, pages = {915-927}, peerreviewed = {Yes}, title = {{A} {Reliability} {Study} of {Light} {Refractive} {Tomography} {Utilized} for {Noninvasive} {Measurement} of {Ultrasound} {Pressure} {Fields}}, volume = {59}, year = {2012} } @article{faucris.123023384, abstract = {In industrial non-destructive testing, x-ray computed tomography (CT) and ultrasonic pulse-echo testing play an important role in the investigation of large-scale samples. One major artifact arises in CT, when the x-ray absorption in specific directions is too intense, so that the material cannot be fully penetrated. Due to different physical interaction principles, ultrasonic imaging is able to show features which are not visible in the CT image. In this contribution, we present a novel fusion method for the complementary data provided by x-ray CT and ultrasonic testing. The ultrasonic data are obtained by an adapted synthetic aperture focusing technique (SAFT) and complement the missing edge information in the CT image. Subsequently, the full edge map is incorporated as a priori information in a modified simultaneous iterative reconstruction method (SIRT) and allows a significant reduction of artifacts in the CT image. © 2013 IOP Publishing Ltd.}, author = {Schrapp, Michael and Scharrer, Thomas and Goldammer, Matthias and Rupitsch, Stefan and Sutor, Alexander and Ermert, Helmut and Lerch, Reinhard}, doi = {10.1088/0957-0233/24/12/125403}, faupublication = {yes}, journal = {Measurement Science & Technology}, keywords = {data fusion; non-destructive testing; ultrasonic testing; x-ray computed tomography}, pages = {1 - 10}, peerreviewed = {Yes}, title = {{Artifact} reduction in non-destructive testing by means of complementary data fusion of x-ray computed tomography and ultrasonic pulse-echo testing}, volume = {24}, year = {2013} } @inproceedings{faucris.239657483, abstract = {
Während klassischerweise ein Nullstellensuchverfahren angewandt wird, wurden neuerdings Verfahren entwickelt, welche auf der Diskretisierung der Bewegungsdifferentialgleichungen beruhen. Diese arbeiten deutlich stabiler und zuverlässiger. Dabei werden die Rayleigh-Lamb-Gleichungen nicht explizit gelöst, sondern der Dispersionszusammenhang auf ein Eigenwertproblem zurückgeführt. Für den Fall der freien Platte kann dieses mit den üblichen numerischen Methoden einfach und effizient gelöst werden.
In der Praxis grenzt jedoch oft ein Fluid an die Platte an. Eine Lamb-Welle gibt dann Energie an die Umgebung ab, was für viele Anwendungsfälle kritisch ist. Die Lamb-Welle erfährt dadurch eine Abstrahldämpfung, welche durch den Imaginärteil der Wellenzahl beschrieben wird. Die Randbedingungen für die Platte führen in diesem Fall zu einem nichtlinearen Eigenwertproblem, für das kein etabliertes Lösungsverfahren existiert. In diesem Beitrag wird eine Lösungsmethodik im Sinne einer Fixpunktiteration präsentiert, sowie Ergebnisse vorgestell},
address = {Berlin},
author = {Kiefer, Daniel A. and Ponschab, Michael and Rupitsch, Stefan},
booktitle = {Fortschritte der Akustik - DAGA 2018},
date = {2018-03-19/2018-03-22},
editor = {Seeber, Bernhard},
faupublication = {yes},
isbn = {978-3-939296-13-3},
keywords = {Lambwellen; Abstrahlung; Spektrale Kollokation; Fluidbelastete Platte},
pages = {1595 - 1598},
peerreviewed = {Yes},
publisher = {Deutsche Gesellschaft für Akustik e.V.},
title = {{Berechnung} der {Abstrahldämpfung} in ebenen {Wellenleitern} aufgrund eines angrenzenden {Fluids}},
venue = {München},
year = {2018}
}
@inproceedings{faucris.220552033,
abstract = {Mechanische Spannungen in einem Festkörper beeinflussen die Ausbreitung
elastischer Wellen. Dieser nichtlineare Effekt wird als
Akustoelastizität bezeichnet und wurde für Volumenwellen ausführlich
behandelt. Seit einigen Jahren wird auch die Auswirkung auf die
Ausbreitung geführter Wellen in üblicherweise eine Methode zur
Nullstellensuche oder eine Finite-Elemente-Methode eingesetzt. Ein
alternativer numerischer Ansatz zur Berechnung der Dispersion von
Lamb-Wellen basiert auf der spektralen Kollokationsmethode. Dieses
Verfahren konvergiert schneller als die anderen Methoden und ist
unkompliziert zu implementieren. In diesem Beitrag werden geführte
Wellen in einer mechanisch vorgespannten Platte modelliert und mittels
spektraler Kollokationsmethode berechnet. Die resultierenden Änderungen
der Phasen- und Gruppengeschwindigkeit stimmen sehr gut mit
Literaturergebnissen überein und werden erörtert. Spannungsgradienten
über die Plattendicke, wie sie beispielsweise durch Biegemomente
hervorgerufen werden, bereiten bei der Modellierung Schwierigkeiten.
Solche Spannungsgradienten wurden bisher durch Schichten mit homogener
Spannung angenähert, wodurch Gradiententerme in den zugrunde liegenden
Gleichungen vernachlässigt wurden. Wie der Einfluss von Biegemomenten
auf die Wellenausbreitung einer Platte ohne diese Vereinfachung mit
Hilfe der spektralen Kollokation berechnet werden kann, wird ebenfalls
in diesem Beitrag vorgestell},
address = {Berlin},
author = {Ponschab, Michael and Kiefer, Daniel A. and Rupitsch, Stefan},
booktitle = {Fortschritte der Akustik - DAGA 2019},
date = {2019-03-18/2019-03-21},
faupublication = {yes},
isbn = {978-3-939296-14-0},
keywords = {Akustoelastischer Effekt; Lamb-Wellen; Geführte Welle},
pages = {1156-1159},
peerreviewed = {unknown},
publisher = {Deutsche Gesellschaft für Akustik e.V},
title = {{Berechnung} der {Auswirkung} mechanischer {Spannungen} auf die {Ausbreitung} von {Lamb}-{Wellen}},
url = {https://www.researchgate.net/profile/Michael{\_}Ponschab/publication/332111219{\_}Berechnung{\_}der{\_}Auswirkung{\_}mechanischer{\_}Spannungen{\_}auf{\_}die{\_}Ausbreitung{\_}von{\_}Lamb-Wellen/links/5ca1be1b45851506d738af96/Berechnung-der-Auswirkung-mechanischer-Spannungen-auf-die-Ausbreitung-von-Lamb-Wellen.pdf},
venue = {Rostock},
year = {2019}
}
@inproceedings{faucris.220905224,
abstract = {Entlang einer Platte können sich unterschiedliche geführte mechanische Wellen ausbreiten, darunter sogenannte Lambwellen. Grenzt ein Fluid an die Platte an, so ändern sich im Allgemeinen die Ausbreitungseigenschaften dieser Wellen erheblich. Dies ist darauf zurückzuführen, dass Energie von der Platte in das Fluid übergeht und dort eine akustische Welle anregt. Für Anwendungen ist häufig die Interaktion zwischen Platte und Fluid maßgeblich. Diese Interaktion kann als abstrahlende Lambwelle modelliert werden und führt zu einem nichtlinearen Eigenwertproblem, welches aus numerischer Sicht schwer zu lösen ist. In diesem Beitrag wird eine Variablentransformation vorgestellt, die das Problem auf ein polynomielles Eigenwertproblem zurückführt. Dies erleichtert das Lösen, da polynomielle Eigenwertprobleme durch Überführen in einen höherdimensionalen Zustandsraum als lineares Eigenwertproblem aufgefasst werden können. Für Letztere existieren hoch effiziente und robuste numerische Lösungsmethoden, die somit nach Anwenden der vorgeschlagenen Transformationen direkt zur Berechnung von abstrahlenden Lambwellen eingesetzt werden können. Im Gegensatz zu konventionellen Nullstellensuchverfahren findet die vorgestellte Methode zuverlässig alle Moden der fluidbelasteten Platte. Wie die resultierenden Dispersionskurven zeigen, können sich die Lösungen erheblich von denen der freien Platte unterscheiden. Die Ergebnisse wurden mit anderen Berechnungen verglichen und zeigen eine sehr gute Übereinstimmung.},
address = {Berlin},
author = {Kiefer, Daniel A. and Ponschab, Michael and Rupitsch, Stefan},
booktitle = {Fortschritte der Akustik - DAGA 2019},
date = {2019-03-18/2019-03-21},
faupublication = {yes},
isbn = {978-3-939296-14-0},
pages = {1152 -- 1155},
peerreviewed = {Yes},
publisher = {Deutsche Gesellschaft für Akustik e.V.},
title = {{Berechnung} der vollständigen {Dispersionscharakteristik} von abstrahlenden {Lambwellen} mittels {Variablentransformation}},
venue = {Rostock},
year = {2019}
}
@inproceedings{faucris.117350464,
author = {Ilg, Jürgen and Rupitsch, Stefan and Sutor, Alexander and Lerch, Reinhard},
booktitle = {Fortschritte der Akustik - DAGA 2010},
faupublication = {yes},
pages = {263-264},
title = {{Bestimmung} der dynamischen {Materialeigenschaften} von künstlichen {Stimmlippen} mittels optischer {Messtechnik}},
year = {2010}
}
@article{faucris.233235508,
abstract = {Sonar sensors are universally applied in autonomous vehicles such as robots and driverless cars as they are inexpensive, energyefficient, and provide accurate range measurements; however, they have some limitations. Their measurements can lead to ambiguous estimates and echo clutter can hamper target detection. In nature, echolocating bats experience similar problems when searching for food, especially if their food source is close to vegetation, as is the case for gleaning bats and nectar-feeding bats. However, nature has come up with solutions to overcome clutter problems and acoustically guide bats. Several bat-pollinated plants have evolved specially shaped floral parts that act as sonar reflectors, making the plants acoustically conspicuous. Here we show that artificial sonar beacons inspired by floral shapes streamline the navigation efficacy of sonarguided robot systems. We developed floral-inspired reflector forms and demonstrate their functionality in 2 proof-of-principle experiments. First we show that the reflectors are easily recognized among dense clutter, and second we show that it is possible to discern different reflector shapes and use this identification to guide a robot through an unfamiliar environment. Bioinspired sonar reflectors could have a wide range of applications that could significantly advance sonar-guided systems.},
author = {Simon, Ralph and Rupitsch, Stefan and Baumann, Markus and Wu, Huan and Peremans, Herbert and Steckel, Jancc},
doi = {10.1073/pnas.1909890117},
faupublication = {yes},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
keywords = {Autonomous navigation; Bioinspired sonar; Echolocation; Robotics; Sonar landmarks},
month = {Jan},
note = {CRIS-Team Scopus Importer:2020-02-04},
pages = {1367-1374},
peerreviewed = {Yes},
title = {{Bioinspired} sonar reflectors as guiding beacons for autonomous navigation},
volume = {117},
year = {2020}
}
@inproceedings{faucris.108820404,
address = {Munich},
author = {Dietz, Markus and Herre, Jürgen and Teichmann, B and Brandenburg, Karlheinz},
booktitle = {102nd AES Convention},
faupublication = {yes},
note = {Vorträge und Veröffentlichungen auf Konferenzen{\_}Gehörangepasste Datenreduktion},
pages = {-},
peerreviewed = {unknown},
publisher = {AES},
title = {{Bridging} the {Gap}: {Extending} {MPEG} {Audio} down to 8 kbit/s},
venue = {Munich},
volume = {Preprint 4508},
year = {1997}
}
@inproceedings{faucris.117742504,
author = {Kaltenbacher, Manfred and Escobar Ramos, Max Eduardo and Hahn, Christian and Ali, Irfan and Becker, Stefan},
booktitle = {Proceedings of ISMA2006: International Conference on Noise and Vibration Engineering},
faupublication = {yes},
note = {UnivIS-Import:2015-04-16:Pub.2006.tech.ITC.stmmec.caaasa},
pages = {633-639},
title = {{CAA} as a post-processing-step within {CFD}-computations},
url = {http://www.isma-isaac.be/past/conf/isma2006/},
venue = {Leuven, Belgien},
volume = {2},
year = {2006}
}
@inproceedings{faucris.220905472,
abstract = {Lamb waves are mechanical waves guided in a plate with stress-free boundaries. In practice, the plate is often in contact with a fluid. The propagation of guided waves may change substantially in this case due to interaction with the adjacent medium, e.g., acoustic radiation may lead to leakage of energy into the fluid domain. The resulting plate modes are called leaky Lamb waves, and their attenuation due to leakage is an important parameter for the design of ultrasonic devices that exploit such waves. Modern methods to calculate dispersion characteristics of guided waves, i.e., the wavenumber-frequency relationship, solve the corresponding discretized eigenvalue problem. This kind of model for leaky Lamb waves with the analytically exact fluid interaction leads to a nonlinear eigenvalue problem, which is difficult to solve. We present a change in variables that yields an equivalent polynomial eigenvalue problem. The latter can be rewritten as a linear eigenvalue problem in state space. As a result, conventional numerical eigenvalue solvers can be used to robustly determine the sought wavenumbers. In contrast to traditional root-finding of the characteristic equations, the presented method guarantees to find all solutions and naturally handles complex wavenumbers. Additionally, no initial guesses for the wavenumbers are required.},
author = {Kiefer, Daniel A. and Ponschab, Michael and Rupitsch, Stefan},
booktitle = {Journal of the Acoustical Society of America 145(3)},
date = {2019-05-12/2019-05-17},
doi = {10.1121/1.5101549},
faupublication = {yes},
pages = {1791--1791},
peerreviewed = {Yes},
publisher = {Acoustical Society of America},
title = {{Calculating} the full leaky {Lamb} wave dispersion characteristics},
url = {https://asa.scitation.org/doi/10.1121/1.5101549},
venue = {Louisville, Kentucky},
volume = {145},
year = {2019}
}
@article{faucris.220905732,
abstract = {Lamb waves are elastodynamic guided waves in plates and are used for non-destructive evaluation, sensors, and material characterization. These applications rely on the knowledge of the dispersion characteristics, i.e., the frequency-dependent wavenumbers. The interaction of a plate with an adjacent fluid leads to a nonlinear differential eigenvalue problem with a square root term describing exchange of energy with the surrounding medium, e.g., via acoustic radiation. In this contribution, a spectral collocation scheme is applied to discretize the differential eigenvalue problem. A change of variable is performed to obtain an equivalent polynomial eigenvalue problem of fourth order, which is linear in state-space and can reliably be solved using modern numerical methods. Traditionally, the leaky Lamb wave problem has been solved by finding the roots of the characteristic equations, a numerically ill-conditioned problem. In contrast to root-finding, the approach described in this paper is inherently able to find all modes and naturally handles complex wavenumbers. The full phase velocity dispersion diagram and attenuation curves are presented and are shown to be in excellent agreement with solutions of the characteristic equation as well as computations made with a perturbation method. The procedure is applicable to anisotropic, viscoelastic, inhomogeneous, and layered plates coupled to an inviscid fluid.},
author = {Kiefer, Daniel A. and Ponschab, Michael and Rupitsch, Stefan and Mayle, Michael},
doi = {10.1121/1.5109399},
faupublication = {yes},
journal = {Journal of the Acoustical Society of America},
pages = {3341--3350},
peerreviewed = {Yes},
title = {{Calculating} the full leaky {Lamb} wave spectrum with exact fluid interaction},
url = {https://asa.scitation.org/doi/10.1121/1.5109399},
volume = {145},
year = {2019}
}
@inproceedings{faucris.245366258,
author = {Gedeon, Dominik and Rupitsch, Stefan and Lerch, Reinhard},
booktitle = {Proceedings of ISPA 2013},
date = {2013-09-20/2013-09-20},
faupublication = {yes},
peerreviewed = {unknown},
title = {{Cantilever} {Design} for a {Rotating} {Energy} {Harvester}},
venue = {Dresden},
year = {2013}
}
@inproceedings{faucris.215000895,
author = {Hiltl, Pia-Theresa and George, Benedikt and Fink, Michael and Rupitsch, Stefan and Ermert, Helmut and Lee, Geoffrey},
booktitle = {3rd European Conference on Pharmaceutics},
date = {2019-03-25/2019-03-26},
faupublication = {yes},
peerreviewed = {unknown},
title = {{Characterisation} of {Sonosensitive} {Nano}-{Sized} {Formulations}},
venue = {Bologna},
year = {2019}
}
@inproceedings{faucris.110119724,
abstract = {For several decades, magnetic sensors have been exploiting the nonlinear relation between the mag-netic field strength and the magnetic flux density. Whereas strong saturation effects were most relevant in the past, today energy consumption of modern sensors plays an increasingly important role. Recent semihard magnetic materials concern this issue by retaining a significant magnetic flux density even when all excitation currents are turned off. Nevertheless, in contrast to classical hard magnets, it is relatively easy to commutate them. With sensor development cycles becoming shorter, there is an in-creasing demand for accurate numerical models concerning hysteresis. In this contribution, we present a new combination of scalar and vector material characterization techniques to compute the remanent magnetic field of a magnetized sample by static finite element (FE) simulations. Vacuumschmelze offers a suitable semihard magnetic material with a coecivity field around 2kA/m that is available as thin stripes. In a first step, the Sensorvac material will be characterized to obtain meaningful material properties required for simulations. With material parameters having been identified, the remanent magnetic field of the magnetized sample will be computed. As it is revealed, simulation results coincide very well with laboratory measurements. In future, the model can be applied to design complex sensors.},
author = {Linnert, Michael and Lerch, Reinhard and Sutor, Alexander and Rupitsch, Stefan},
booktitle = {PROCEEDINGS – AMA Conferences 2017 AMA Conferences 2017 Nuermberg Exhibition Centre, Germany 30.5. – 1.6.2017 SENSOR 2017 18th International Conference on Sensors and Measurement Technology IRS2 2017},
date = {2017-05-30/2017-06-01},
doi = {10.5162/sensor2017/C8.4},
editor = {AMA Service GmbH},
faupublication = {yes},
keywords = {FEM, magnetics, hysteresis, material properties, remanent field},
pages = {424-428},
peerreviewed = {unknown},
title = {{Characterization} and {Simulation} of a {Magnetized} {Sample}},
venue = {Nürnberg},
year = {2017}
}
@inproceedings{faucris.206145645,
author = {Hiltl, Pia-Theresa and Fink, Michael and Hofmann, Astrid and Ermert, Helmut and Rupitsch, Stefan and Lee, Geoffrey},
booktitle = {Biomedizinische Tagung 2018},
date = {2018-09-26/2018-09-28},
faupublication = {yes},
peerreviewed = {unknown},
title = {{Characterization} of {Acoustic} {Properties} of {Poly}-({L})-lactic {Acid} {Nanoparticles} in terms of {Inertial} {Cavitation}},
venue = {Aachen},
year = {2018}
}
@inproceedings{faucris.117344964,
author = {Wolf, Felix and Sutor, Alexander and Rupitsch, Stefan and Lerch, Reinhard},
booktitle = {Proceedings Sensor + Test 2011},
faupublication = {yes},
pages = {328-333},
peerreviewed = {unknown},
title = {{Characterization} of {Dynamic} {Hysteresis} {Behavior} of {Ferroelectric} {Actuators}},
year = {2011}
}
@inproceedings{faucris.123959924,
abstract = {Material constants of manganese-doped sodium potassium niobate (NKN) were characterized by the Inverse Method, which provides material constants by minimizing deviations between frequency-resolved electrical impedance measurements and finite element simulations. Impedance curves of two different types of ceramic samples featuring same geometric shape but different polarization directions, were measured in the temperature range of -25 degrees C to 150 degrees C. Material constants at each temperature were characterized by using the measured impedance curves. As a result, an anisotropic decrease of the elastic stiffness constants was observed with increasing temperature. It can be assumed that this temperature dependency is attributed to orthorhombic-tetragonal phase transition. Furthermore, the maximum loss factor was obtained at 75 degrees C, which caused minimum impedance range of all resonance-antiresonance pairs at the same temperature.},
author = {Ogo, Kenji and Weiß, Manuel and Rupitsch, Stefan and Lerch, Reinhard and Kakimoto, Ken-Ichi},
booktitle = {Ultrasonics Symposium (IUS), 2015 IEEE International},
doi = {10.1109/ULTSYM.2015.0253},
faupublication = {yes},
keywords = {lead-free;Inverse Method;piezoceramics},
month = {Jan},
peerreviewed = {unknown},
publisher = {Institute of Electrical and Electronics Engineers (IEEE)},
title = {{Characterization} of lead-free alkali niobate piezoceramics by the {Inverse} {Method}},
venue = {Taipei},
year = {2015}
}
@inproceedings{faucris.123499024,
author = {Wolf, Felix and Sutor, Alexander and Rupitsch, Stefan and Lerch, Reinhard},
booktitle = {7th International Workshop on Direct and Inverse Problems in Piezoelectricity - Book of Abstracts},
faupublication = {yes},
peerreviewed = {unknown},
title = {{Characterization} of piezoceramic materials using a modified scalar {Preisach} model with an analytic weight function},
year = {2011}
}
@incollection{faucris.255825139,
abstract = {The metrological characterization of sound fields represents an important step in the design and optimization of ultrasonic transducers. In this chapter, we will concentrate on the so-called light refractive tomography (LRT), which is an optical-based measurement principle. It allows noninvasive, spatially as well as temporally resolved acquisition of both, sound fields in fluids and mechanical waves in optical transparent solids. Before the history and fundamentals (e.g., tomographic reconstruction) of LRT are studied in Sects. 8.2 and 8.3, we will discuss conventional measurement principles (e.g., hydrophones) for such measuring tasks. Section 8.4 addresses the application of LRT for investigating sound fields in water. For instance, the disturbed sound field due to a capsule hydrophone will be quantified. In Sect. 8.5, LRT results for airborne ultrasound are shown and verified through microphone measurements. Finally, LRT will be exploited to quantitatively acquire the propagation of mechanical waves in optically transparent solids, which is currently impossible by means of conventional measurement principles.},
author = {Rupitsch, Stefan},
booktitle = {Topics in Mining, Metallurgy and Materials Engineering},
doi = {10.1007/978-3-662-57534-5{\_}8},
faupublication = {yes},
note = {CRIS-Team Scopus Importer:2021-04-20},
pages = {341-406},
peerreviewed = {unknown},
publisher = {Springer Science and Business Media Deutschland GmbH},
series = {Topics in Mining, Metallurgy and Materials Engineering},
title = {{Characterization} of {Sound} {Fields} {Generated} by {Ultrasonic} {Transducers}},
year = {2019}
}
@article{faucris.215876804,
abstract = {Ultrasonic sonar sensors are commonly used for contactless distance measurements in application areas such as automotive and mobile robotics. They can also be exploited to identify and classify sound-reflecting objects (targets), which may then be used as landmarks for navigation. In the presented work, sonar targets of different geometric shapes and sizes are classified with custom-engineered features. Artificial neural networks (ANNs) with multiple hidden layers are applied as classifiers and different features are tested as well as compared. We concentrate on features that are related to target strength estimates derived from pulse-compressed echoes. In doing so, one is able to distinguish different target geometries with a high rate of success and to perform tests with ANNs regarding their capabilities for size discrimination of targets with the same geometric shape. A comparison of achievable classifier performance with wideband and narrowband chirp excitation signals was conducted as well. The research indicates that our engineered features and excitation signals are suitable for the target classification task.},
author = {Kroh, Patrick and Simon, Ralph and Rupitsch, Stefan},
doi = {10.3390/s19051176},
faupublication = {yes},
journal = {Sensors},
note = {CRIS-Team WoS Importer:2019-04-12},
peerreviewed = {Yes},
title = {{Classification} of {Sonar} {Targets} in {Air}: {A} {Neural} {Network} {Approach}},
volume = {19},
year = {2019}
}
@article{faucris.268225398,
abstract = {Using the seminal rubber hand illusion and related paradigms, the last two decades unveiled the multisensory mechanisms underlying the sense of limb embodiment, that is, the cognitive integration of an artificial limb into one's body representation. Since also individuals with amputations can be induced to embody an artificial limb by multimodal sensory stimulation, it can be assumed that the involved computational mechanisms are universal and independent of the perceiver's physical integrity. This is anything but trivial, since experimentally induced embodiment has been related to the embodiment of prostheses in limb amputees, representing a crucial rehabilitative goal with clinical implications. However, until now there is no unified theoretical framework to explain limb embodiment in structurally varying bodies. In the present work, we suggest extensions of the existing Bayesian models on limb embodiment in normally-limbed persons in order to apply them to the specific situation in limb amputees lacking the limb as physical effector. We propose that adjusted weighting of included parameters of a unified modeling framework, rather than qualitatively different model structures for normally-limbed and amputated individuals, is capable of explaining embodiment in structurally varying bodies. Differences in the spatial representation of the close environment (peripersonal space) and the limb (phantom limb awareness) as well as sensorimotor learning processes associated with limb loss and the use of prostheses might be crucial modulators for embodiment of artificial limbs in individuals with limb amputation. We will discuss implications of our extended Bayesian model for basic research and clinical contexts.},
author = {Bliek, Adna and Bekrater-Bodmann, Robin and Beckerle, Philipp},
doi = {10.3389/fpsyg.2021.716976},
faupublication = {yes},
journal = {Frontiers in Psychology},
keywords = {bodily illusions; cognitive model; embodiment; rubber limb illusion; structurally varying bodies},
note = {Created from Fastlane, Scopus look-up},
peerreviewed = {Yes},
title = {{Cognitive} {Models} of {Limb} {Embodiment} in {Structurally} {Varying} {Bodies}: {A} {Theoretical} {Perspective}},
volume = {12},
year = {2021}
}
@inproceedings{faucris.264269058,
abstract = {Online trajectory planning allows robotic manipulators to adapt to changing environments and dynamic tasks, which becomes increasingly relevant through human-robot interaction. optimizing motion objectives is a common way of planning but is usually conducted in joint space, whereas many planning objectives are rather defined in task space. Joint Space Planning (JSP) first transforms target poses into joint space and then performs conventional optimization. Implicit Task Space Planning (ITSP) uses a special objective function to directly consider task quantities and is similar to economic model predictive control. Remarkably, comparative studies of both approaches with respect to their performance are scarce. This contribution aims at filling this gap by providing a systematic analysis of both methods using a 6-DoF collaborative robot in practical experiments. Results show that the first method is less sensitive to local minima and profits from active reconfiguration abilities while it generates less straight-lined motions and is not able to account for target manifolds in the task space. The second method can easily consider target manifolds and performs more straight-lined motions while it is more sensitive to local minima and provides active reconfiguration only partially. Although the cost function of the second method is significantly more complex, the computational effort relativizes during planning.},
author = {Kramer, Maximilian and Velasco Guillen, Rodrigo Jose and Beckerle, Philipp and Bertram, Torsten},
booktitle = {IEEE/ASME International Conference on Advanced Intelligent Mechatronics, AIM},
date = {2021-07-12/2021-07-16},
doi = {10.1109/AIM46487.2021.9517608},
faupublication = {yes},
isbn = {9781665441391},
keywords = {Human-Robot-Collaboration; Online Trajectory optimization; Task Space Motion Planning},
note = {CRIS-Team Scopus Importer:2021-09-24},
pages = {223-230},
peerreviewed = {unknown},
publisher = {Institute of Electrical and Electronics Engineers Inc.},
title = {{Comparing} online robot joint space trajectory optimization for task space applications},
venue = {Delft},
volume = {2021-July},
year = {2021}
}
@inproceedings{faucris.225447486,
abstract = {The Mayergoyz vector Preisach model is oftentimes used for the simulation of hysteresis phenomena of both
isotropic and anisotropic ferromagnetic materials. However, the derivation of the required Preisach weights as well as the efforts to resolve the full 2D/3D space may lead to rather high computational costs. For isotropic materials, two other vector Preisach models developed by Sutor might offer a light-weight alternative. In this contribution, we compare three different vector Preisach models with respect to their representation of measured data and their computational costs.
The numerical computation of magnetization processes in moving and rotating assemblies requires the usage of vector hysteresis models. A commonly used model is the so-called Mayergoyz vector Preisach model, which applies the scalar Preisach model into multiple angles of the halfspace. The usage of several scalar models, which are optionally weighted differently, enables the description of isotropic as well as anisotropic materials. The flexibility is achieved, however, at the cost of multiple scalar model evaluations. For solely isotropic materials, two vector Preisach models, based on an extra rotational operator, might offer a lightweight alternative in terms of evaluation cost. The study aims at comparing the three mentioned models with respect to computational efficiency and practical applicability.
The three mentioned vector Preisach models are compared with respect to their computational costs and their representation of magnetic polarization curves measured by a vector vibrating sample magnetometer.
The results prove the applicability of all three models to practical scenarios and show the higher efficiency of the vector models based on rotational operators in terms of computational time.
Although the two vector Preisach models, based on an extra rotational operator, have been proposed in 2012 and 2015, their practical application and inversion has not been tested yet. This paper not only shows the usability of these particular vector Preisach models but also proves the efficiency of a special stageless evaluation approach that was proposed in a former contribution.
In Lehrveranstaltungen lassen sich physikalische Effekte und deren zugrunde liegende Theorie anschaulich anhand von Experimenten verdeutlichen. Besonderes Interesse wird hierbei durch optische, akustische und olfaktorische Sinneswahrnehmungen und vor allem durch die Kombination dieser Reize geweckt. Plasma-Lautsprecher stellen vor diesem Hintergrund ein hervorragendes Anschauungsobjekt für die Physikdidaktik im Fachgebiet „Akustik“ mit hohem motivierendem Potenzial dar.
Im Rahmen dieses Betrags wird ein einfaches, verständliches und kostengünstiges Schaltungskonzept für einen Plasma-Lautsprecher vorgestellt und der zugrundeliegende Schallentstehungsmechanismus anschaulich erläutert. Anhand der vorgestellten Experimente können die Lernenden die akustischen Eigenschaften des Lautsprechers qualitativ und quantitativ untersuchen. Abschließend wird ein didaktisches Konzept für den Versuch gegeben. Der didaktische Schwerpunkt des Versuchs kann nach Vorwissen der Lernenden an die Zielgruppe angepasst werden.drift of electromagnetic flow meters. We will extend the
conventional discrete time alternating field method to continuous
operation. A Kalman filter, based on a state space model of the
sensor, was developed to separate the flow-proportional signal
from the noisy voltage drift of the electrodes. The new algorithm
allows to process flow information rarely used today, i.e., the
electrode voltage during times of stable magnetic field. Thereby
a lower energy consumption and an increased accuracy can
be achieved. Compared to conventional signal processing, the
performance of the new method is far more independent of
the transient behavior of the actual flow. Measurements show
a comparable accuracy, but with a significantly reduced energy
demand. Off-line signal processing let expect a theoretical power
reduction factor around 15}, author = {Linnert, Michael and Mariager, Simon and Rupitsch, Stefan and Lerch, Reinhard}, booktitle = {2018 IEEE International Instrumentation and Measurement Technology Conference (I2MTC 2018) Proceedings}, date = {2018-05-14/2018-05-17}, doi = {10.1109/I2MTC.2018.8409600}, editor = {IEEE}, faupublication = {yes}, isbn = {978-1-5386-2222-3}, keywords = {electromagnetic flow meter; energy consumption; accuracy; Kalman filter; data fusion; state space; signal processing}, pages = {674 - 679}, peerreviewed = {Yes}, title = {{Dynamic} {Offset} {Correction} of {Electromagnetic} {Flow} {Meters}}, venue = {Houston}, year = {2018} } @article{faucris.121067584, abstract = {We report on the frequency dependent behavior of dielectric elastomer actuators (DEA). The introduced smart material actuators consist of 3M™'s elastomer VHB™4905 (9469) and a compliant, sputtered copper electrode on each side. The presented experiments on these compounds contain the active tuning of their resonance frequency and their application as acoustic actuators.We are able to decrease the membranes' eigenfrequency by 30% with an electrical offset potential. Alternatively, if an alternating signal is applied, sound pressure levels up to 130 dB in an enclosed volume of 28 ccm are achieved. In order to verify the results, a numerical simulation is introduced incorporating the two physical fields involved: electrical and mechanical. © 2012 Springer-Verlag.}, author = {Hochradel, Klaus and Rupitsch, Stefan and Sutor, Alexander and Lerch, Reinhard and Vu, Duc Khoi and Steinmann, Paul}, doi = {10.1007/s00339-012-6837-2}, faupublication = {yes}, journal = {Applied Physics A-Materials Science & Processing}, note = {UnivIS-Import:2015-04-14:Pub.2012.tech.FT.FT-TM.dynami}, pages = {-}, peerreviewed = {Yes}, title = {{Dynamic} performance of dielectric elastomers utilized as acoustic actuators}, year = {2012} } @inproceedings{faucris.114300824, abstract = {In order to compensate for hysteresis errors in tracking and manipulation tasks, models describing the piezoceramic actuator nonlinearities are required. These models have to meet the following two criteria: (i) Efficiency and (ii) a bidirectional description of hysteresis phenomena. Due to its flexibility and efficiency, the Preisach operator is a promising tool to model transfer behavior of ferroelectric actuators in forward direction. However, the model cannot be inverted analytically. The scope of this contribution is therefore to introduce a novel, efficient algorithm for the numerical inversion of the Preisach operator. The algorithm is characterized as well as applied to linearize the voltage-deflection hysteresis of trimorph bending actuators. It is shown that independent of the model discretization, a maximum sampling frequency of 6.5 kHz is allowed for the proposed numerical inversion scheme. As result of this fast inversion technique, the Preisach model becomes interesting for real-time hysteresis compensation tasks. It shows to be competitive to other hysteresis models which are directly invertible, such as the Prandtl-Ishlinskii hysteresis operator.}, author = {Wolf, Felix and Hirsch, Hartmut and Sutor, Alexander and Rupitsch, Stefan and Lerch, Reinhard}, faupublication = {yes}, month = {Jan}, pages = {171-174}, peerreviewed = {Yes}, title = {{Efficient} {Compensation} of {Nonlinear} {Transfer} {Characteristics} for {Piezoceramic} {Actuators}}, year = {2013} } @inproceedings{faucris.114460984, abstract = {A semi-numerical simulation approach, the so-called SIRFEM is presented. This approach can be applied to efficiently predict transient output signals of ultrasonic imaging systems operating in pulse-echo mode. In particular, we concentrate on acoustic microscopes, which exploit ultrasound waves with center frequencies >10 MHz to visualize inner structures of solid specimens. While the ultrasound pulses between ultrasonic transducer and specimen surface are analytically modeled (spatial impulse response), we perform finite element simulations to describe wave propagation in the specimen. As the computed B-mode images for a plastic sample containing various inclusions (e.g., air) demonstrate, SIRFEM provides reliable transducer outputs. This implies that both, reflections at inner structures and multiple reflections between specimen surface and those structures are considered.}, author = {Rupitsch, Stefan and Nierla, Michael}, booktitle = {13th IEEE SENSORS Conference, SENSORS 2014}, date = {2014-11-02/2014-11-05}, doi = {10.1109/ICSENS.2014.6985338}, faupublication = {yes}, pages = {1656-1659}, peerreviewed = {Yes}, publisher = {Institute of Electrical and Electronics Engineers Inc.}, title = {{Efficient} numerical simulation of transducer outputs for acoustic microscopes}, venue = {Valencia}, year = {2014} } @article{faucris.210791941, author = {Grabinger, Jens and Kaltenbacher, Manfred and Becker, Stefan and Zenger, Florian}, doi = {10.4271/2018-01-1518}, faupublication = {yes}, journal = {SAE Technical Papers}, peerreviewed = {Yes}, title = {{Efficient} prediction of flow-induced sound sources and emission from a {HVAC} blower}, year = {2018} } @article{faucris.280839649, abstract = {Electromyography (EMG) signals have been used in designing muscle-machine interfaces (MuMIs) for various applications, ranging from entertainment (EMG controlled games) to human assistance and human augmentation (EMG controlled prostheses and exoskeletons). For this, classical machine learning methods such as Random Forest (RF) models have been used to decode EMG signals. However, these methods depend on several stages of signal pre-processing and extraction of hand-crafted features so as to obtain the desired output. In this work, we propose EMG based frameworks for the decoding of object motions in the execution of dexterous, in-hand manipulation tasks using raw EMG signals input and two novel deep learning (DL) techniques called Temporal Multi-Channel Transformers and Vision Transformers. The results obtained are compared, in terms of accuracy and speed of decoding the motion, with RF-based models and Convolutional Neural Networks as a benchmark. The models are trained for 11 subjects in a motion-object specific and motion-object generic way, using the 10-fold cross-validation procedure. This study shows that the performance of MuMIs can be improved by employing DL-based models with raw myoelectric activations instead of developing DL or classic machine learning models with hand-crafted features.}, author = {Godoy, Ricardo V. and Dwivedi, Anany and Liarokapis, Minas}, doi = {10.1109/TNSRE.2022.3196622}, faupublication = {yes}, journal = {IEEE Transactions on Neural Systems and Rehabilitation Engineering}, keywords = {Brain modeling; Data models; Decoding; Deep Learning; Dexterous Manipulation; Electromyography; Electromyography; Feature extraction; Motion Decoding; Task analysis; Transformers; Transformers}, note = {CRIS-Team Scopus Importer:2022-08-19}, pages = {1-1}, peerreviewed = {Yes}, title = {{Electromyography} {Based} {Decoding} of {Dexterous}, {In}-{Hand} {Manipulation} {Motions} with {Temporal} {Multi}-{Channel} {Vision} {Transformers}}, year = {2022} } @inproceedings{faucris.285685533, abstract = {With an increasing use of robotic and bionic devices for the execution of everyday life, complex tasks, Electromyography (EMG) based interfaces are being explored as candidate technologies for facilitating an intuitive interaction with such devices. However, EM G-based interfaces typically require appropriate features to be extracted from the raw EMG signals using a plethora of feature extraction methods to achieve excellent performance in practical applications. To select an appropriate feature set that will lead to significant EMG-based decoding performance, a deep understanding of available methods and the human musculoskeletal system is needed. To overcome this issue, researchers have proposed the use of deep learning methods for automatically extracting complex features directly from the raw EMG data. In this work, we propose Temporal Multi-Channel Vision Transformers as a deep learning technique that has the potential to achieve dexterous control of robots and bionic hands. The performance of this method is evaluated and compared with other well-known methods, employing the open-Access Ninapro dataset.}, author = {Godoy, Ricardo V. and Lahr, Gustavo J.G. and Dwivedi, Anany and Reis, Tharik J.S. and Polegato, Paulo H. and Becker, Marcelo and Caurin, Glauco A.P. and Liarokapis, Minas}, booktitle = {Proceedings of the IEEE RAS and EMBS International Conference on Biomedical Robotics and Biomechatronics}, date = {2022-08-21/2022-08-24}, doi = {10.1109/BioRob52689.2022.9925307}, faupublication = {yes}, isbn = {9781665458498}, note = {CRIS-Team Scopus Importer:2022-11-25}, peerreviewed = {unknown}, publisher = {IEEE Computer Society}, title = {{Electromyography}-{Based}, {Robust} {Hand} {Motion} {Classification} {Employing} {Temporal} {Multi}-{Channel} {Vision} {Transformers}}, venue = {Seoul}, volume = {2022-August}, year = {2022} } @article{faucris.280350733, abstract = {With an increasing use of robotic and bionic devices for the execution of everyday life, complex tasks, Electromyography (EMG) based interfaces are being explored as candidate technologies for facilitating an intuitive interaction with such devices. However, EMG-based interfaces typically require appropriate features to be extracted from the raw EMG signals using a plethora of feature extraction methods to achieve excellent performance in practical applications. To select an appropriate feature set that will lead to significant EMG-based decoding performance, a deep understanding of available methods and the human musculoskeletal system is needed. To overcome this issue, researchers have proposed the use of deep learning methods for automatically extracting complex features directly from the raw EMG data. In this work, we propose Temporal Multi-Channel Vision Transformers as a deep learning technique that has the potential to achieve dexterous control of robots and bionic hands. The performance of this method is evaluated and compared with other well-known methods, employing the open-access Ninapro dataset.}, author = {Godoy, Ricardo V. and Lahr, Gustavo J.G. and Dwivedi, Anany and Reis, Tharik J.S. and Polegato, Paulo H. and Becker, Marcelo and Caurin, Glauco A.P. and Liarokapis, Minas}, doi = {10.1109/LRA.2022.3192623}, faupublication = {yes}, journal = {IEEE Robotics and Automation Letters}, keywords = {Brain modeling; Computer architecture; Deep Learning in Grasping and Manipulation; Deep Learning Methods; Electromyography; Feature extraction; In-Hand Manipulation; Muscles; Prosthetics and Exoskeletons; Task analysis; Transformers}, note = {CRIS-Team Scopus Importer:2022-08-12}, pages = {1-8}, peerreviewed = {Yes}, title = {{Electromyography}-{Based}, {Robust} {Hand} {Motion} {Classification} {Employing} {Temporal} {Multi}-{Channel} {Vision} {Transformers}}, year = {2022} } @book{faucris.112961464, abstract = {Dieses Lehrbuch bietet eine umfassende Einführung in die moderne Elektrische Messtechnik. Behandelt werden: die Fehlerrechnung systematischer und zufälliger Fehler, die Erfassung von dynamischen Messfehlern und ihren Korrekturen, Geräte und Verfahren der analogen Messtechnik, wie z.B. Standard-Messgeräte, elektronische Messverstärker, Messbrücken. Anschließend werden Analog-Digital- und Digital-Analog-Umsetzer sowie digitale Messgeräte beschrieben. Ein weiterer Schwerpunkt des Buches ist die ausführliche Behandlung der modernen computerunterstützten Messdatenerfassung und Messsignalverarbeitung bezüglich Hard- und Software. In der 7. Auflage wurde der neueste Stand auf dem Gebiet der automatisierten Messdatenerfassung aufgenommen. Dazu zählen insbesondere neuere Schnittstellen, wie z.B. Flexray, sowie die Erweiterung von Standardschnittstellen, z.B. CAN-Bus. Es ist eine DVD mit Übungsaufgaben zur rechnergestützten Messdatenerfassung und Messsignalverarbeitung sowie zur Programmierung von Speicherprogrammierbaren Steuerungen (SPS) enthalten. Via Internet kann der Leser eine am Lehrstuhl für Sensorik aufgebaute SPS programmieren sowie weitere Übungsaufgaben und Lösungen zu den Programmieraufgaben von der DVD herunterladen. Die DVD enthält außerdem eine Studentenversion von LabVIEW.
Die Zielgruppen Das Buch eignet sich in Verbindung mit dem Werk "Elektrische Messtechnik/Übungsbuch" für Studierende der Ingenieur- und Naturwissenschaften sowie für den in der Praxis tätigen Ingenieur auch zum Selbststudium.},
address = {Heidelberg},
author = {Lerch, Reinhard},
edition = {7. Auflage},
faupublication = {yes},
isbn = {978-3-662-46940-8},
peerreviewed = {unknown},
publisher = {Springer Vieweg},
title = {{Elektrische} {Messtechnik} {Analoge}, digitale und computergestützte {Verfahren}},
year = {2016}
}
@book{faucris.122983124,
address = {Heidelberg},
author = {Lerch, Reinhard},
edition = {6. Auflage},
faupublication = {yes},
isbn = {978-3-642-22608-3},
peerreviewed = {unknown},
publisher = {Springer Vieweg},
title = {{Elektrische} {Messtechnik}},
year = {2012}
}
@article{faucris.273939420,
author = {Beckerle, Philipp and Castellini, Claudio and Lenggenhager, Bigna and Dosen, Strahinja},
doi = {10.3389/fnbot.2022.871785},
faupublication = {yes},
journal = {Frontiers in Neurorobotics},
keywords = {agency; brain plasticity; cognitive models; constructivist psychology; embodiment; human-machine interfaces; sensorimotor control and learning},
note = {CRIS-Team Scopus Importer:2022-04-29},
peerreviewed = {Yes},
title = {{Embodiment} and {Co}-{Adaptation} through {Human}-{Machine} {Interfaces}: at the border of {Robotics}, {Neuroscience} and {Psychology}},
url = {https://www.frontiersin.org/articles/10.3389/fnbot.2022.871785},
volume = {16},
year = {2022}
}
@article{faucris.201353963,
abstract = {Es wird die Entwicklung und Optimierung eines piezoelektrischen Energy-Harvesting-Systems zur autarken Energieversorgung
einer Güterverfolgungsanwendung im Logistikbereich vorgestellt. Das Energy-Harvesting-System ist zusammen mit einem
Funksender an einem zu ortenden Objekt angebracht. Durch Erschütterungen bei Bewegung des Objekts wird solange elektrische
Energie gewandelt und zwischengespeichert, bis genügend vorhanden ist, um eine ortbare Funknachricht mit der
Identifikationsnummer des Objekts zu senden. Zur Entwicklung des Harvesters werden zunächst Designkriterien für die
optimale Geometrie biegebalkenbasierter piezoelektrischer Energy-Harvester anhand analytischer Methoden ermittelt. Im
Anschluss wird das Harvesting-System auf die mechanische Anregung und den elektrischen Energiebedarf hin absolut
dimensioniert. Um auch das nichtlineare elektrische Netzwerk zur Energieextraktion und dessen Rückwirkung auf den
Harvester korrekt zu berücksichtigen, kommt hierbei ein spezieller modal reduzierter Simulationsansatz in Verbindung mit
realistischen Finite-Elemente-Simulationen zum Einsatz. Anschließend wird die Energieextraktionsschaltung hinsichtlich
ihrer Energieextraktions-Effizienz und der Einsetzbarkeit für verschiedene Anregungsszenarien ausgelegt. Die
Funktionalität des Energy-Harvesting-Systems, bestehend aus Energy-Harvester, Energieextraktionsnetzwerk und
Funkschaltung, konnte abschließend für verschiedene Anregungsszenarien nachgewiesen werde},
author = {Dorsch, Philipp and Gedeon, Dominik and Weiß, Manuel and Rupitsch, Stefan},
doi = {10.1515/teme-2017-0102},
faupublication = {yes},
journal = {Technisches Messen},
keywords = {Piezoelektrizität; Energy-Harvesting; Finite-Elemente-Methode; Optimierung},
peerreviewed = {Yes},
title = {{Entwicklung} und {Optimierung} eines piezoelektrischen {Energy}-{Harvesting}-{Systems} zur {Energieversorgung} eines {Güterverfolgungssystems} im {Logistikbereich}},
url = {https://www.degruyter.com/downloadpdf/j/teme.ahead-of-print/teme-2017-0102/teme-2017-0102.pdf},
year = {2017}
}
@inproceedings{faucris.117350684,
author = {Rupitsch, Stefan and Sutor, Alexander and Ilg, Jürgen and Wolf, Felix and Lerch, Reinhard},
booktitle = {6th International Workshop on Direct and Inverse Problems in Piezoelectricity - Book of Abstracts},
faupublication = {yes},
title = {{Estimation} of {Material} {Parameters} for {Piezoelectric} {Actuators} {Using} {Electrical} and {Mechanical} {Quantities}},
year = {2010}
}
@inproceedings{faucris.255627672,
abstract = {In this contribution, we will classify sonar targets in air. The gained semantic environment information may be beneficial for autonomous mobile systems, such as robots and transport systems, for navigation in unknown as well as challenging settings with little or ambiguous optical and electromagnetic features. Examples for aforementioned environments may include food processing plants as well as medical buildings, in which obstacles are often comprised of transparent plastic or glass and may also have large shiny/reflecting surfaces. Targets are classified into three generic categories (flat, convex, concave), based on echoes from three subsequent recording positions. Multiple artificial neural networks with different architectures are designed, trained and evaluated as classifiers. The networks show promising prediction accuracy and an embedded implementation appears to be feasible. Especially, combinations of capsule networks and long short-term memory networks appear to be promising candidates for high classification performance.},
author = {Kroh, Patrick and Mrochen, Jan and Rupitsch, Stefan},
booktitle = {Proceedings of IEEE Sensors},
date = {2020-10-25/2020-10-28},
doi = {10.1109/SENSORS47125.2020.9278686},
faupublication = {yes},
isbn = {9781728168012},
keywords = {feature extraction; neural networks; sonar detection; sonar measurements},
note = {CRIS-Team Scopus Importer:2021-04-19},
peerreviewed = {unknown},
publisher = {Institute of Electrical and Electronics Engineers Inc.},
title = {{Evaluation} of {Neural} {Network} {Architectures} for {Classification} of {Sonar} {Echoes} in {Air}},
volume = {2020-October},
year = {2020}
}
@inproceedings{faucris.285686516,
abstract = {Elastic actuator design is primarily motivated by safety in human-robot interaction and energy efficiency. However, the increased complexity when compared to direct drives, makes the system prone to technical faults in elastic and kinematic elements. On the other hand, Variable Stiffness Actuators (VSA) often introduce non-linear torque-deformation relationships. We propose a stiffness-fault-Tolerant control strategy for elastic actuators with non-linear compliant characteristics, capable of adapting to stiffness changes. The control strategy is demonstrated experimentally in a MACCEPA-based elastic actuator designed to power a knee exoskeleton. We develop the general model-based control scheme based on impedance control and adapt it to the experimental actuation system. Experiential evaluations under oscillatory and sigmoid trajectories are considered to analyze performance. Results demonstrate that the control system is capable of accurately tracking a reference trajectory under stiffness variations and interaction disturbance.},
author = {Velasco Guillen, Rodrigo Jose and Grosu, Victor and Vanderborght, Bram and Font-Llagunes, Josep M. and Beckerle, Philipp},
booktitle = {Proceedings of the IEEE RAS and EMBS International Conference on Biomedical Robotics and Biomechatronics},
date = {2022-08-21/2022-08-24},
doi = {10.1109/BioRob52689.2022.9925448},
faupublication = {yes},
isbn = {9781665458498},
note = {CRIS-Team Scopus Importer:2022-11-25},
peerreviewed = {unknown},
publisher = {IEEE Computer Society},
title = {{Experimental} {Evaluation} of a {Stiffness}-{Fault}-{Tolerant} {Control} {Strategy} on an {Elastic} {Actuator} for {Wearable} {Robotics}},
venue = {Seoul},
volume = {2022-August},
year = {2022}
}
@inproceedings{faucris.117759444,
abstract = {For the investigation of the physical processes of the human phonation a fluid-structure-coupled in-vitro model was developed, which constitutes a copy of the human larynx. With that model one was able to reproduce a manlike process of sound production. The model made it possible to enforce extensive observations of the flow-induced vocal fold vibrations. Many measurement techniques were applied as high-speed flow visualization, particle image velocimetry (PIV) of the time-dependent flow field, unsteady pressure measurement, vibration measurement by a laser-scanning vibrometer as well as the measurement of the acoustic field. Furthermore correlations were done between the acoustic field, the flow velocity and the displacement of the vocal fold models. The results support the existence of the Coanda-effect during phonation. The flow attaches to one vocal fold just past the glottis and forms a spacious vortex behind the vocal folds. That behavior is not linked to one vocal fold and changes stochastically from cycle to cycle. The sound production is presumed to be produced by oscillations of the vocal folds and therefore by the involved oscillating volume flow rate.},
author = {Kniesburges, Stefan and Becker, Stefan and Müller, Stefan and Delgado, Antonio and Link, Gerhard and Kaltenbacher, Manfred and Döllinger, Michael},
booktitle = {Proceedings - European Conference on Noise Control},
date = {2008-06-29/2008-07-04},
faupublication = {yes},
note = {UnivIS-Import:2015-04-16:Pub.2008.tech.ITC.stmmec.experi{\_}7},
pages = {5131-5136},
title = {{Experimental} study of the fluid-structure-acoustic interaction in a human voice model},
url = {http://webistem.com/acoustics2008/acoustics2008/cd1/data/articles/002222.pdf},
venue = {Paris, Frankreich},
year = {2008}
}
@article{faucris.111951444,
author = {Becker, Stefan and Kniesburges, Stefan and Müller, Stefan and Delgado, Antonio and Kaltenbacher, Barbara},
doi = {10.1002/cite.200750483},
faupublication = {yes},
journal = {Chemie Ingenieur Technik},
note = {UnivIS-Import:2015-03-09:Pub.2008.tech.ITC.stmmec.experi{\_}17},
pages = {1284-1285},
peerreviewed = {Yes},
title = {{Experimentelle} {Modellbildung} der {Fluid}-{Struktur}-{Akustik}-{Wechselwirkung} bei der menschlichen {Stimmgebung}},
url = {http://onlinelibrary.wiley.com/doi/10.1002/cite.200750483/pdf},
volume = {80},
year = {2008}
}
@incollection{faucris.123130084,
address = {Hannover},
author = {Behr, Oliver and Brinkmann, Robert and Hochradel, Klaus and Hurst, Johanna and Mages, Jürgen and Naucke, Andreas and Nagy, Martina and Niermann, Ivo and Reers, Hendrik and Simon, Ralph and Weber, Natalie and Korner-Nievergelt, Fränzi},
booktitle = {Reduktion des Kollisionsrisikos von Fledermäusen an Onshore-Windenergieanlagen (RENEBAT II)},
editor = {Oliver Behr, Robert Brinkmann, Fränzi Korner-Nievergelt, Martina Nagy, Ivo Niermann, Michael Reich & Ralph Simon},
faupublication = {no},
peerreviewed = {unknown},
publisher = {Schriftenreihe Institut für Umweltplanung, Leibniz Universität Hannover},
series = {Umwelt und Raum},
title = {{Experimenteller} {Test} der ledermausfreundlichen {Betriebsalgorithmen}},
volume = {7},
year = {2015}
}
@inproceedings{faucris.114769644,
abstract = {Faser-Kunststoff-Verbunde (FKV) ermöglichen durch ihren schichtweisen Aufbau die Integration von Sensoren und Aktoren in den Verbundaufbau. Hierdurch können zahlreiche neuartige Bauteilfunktionalitäten wie etwa Abstands- oder Durchflussmesssysteme erschlossen werden. Dabei kann durch die Integration mehrerer piezoelektrischer Aktoren sowie deren gezielte zeitversetzte Ansteuerung eine gerichtete Plattenwelle erzeugt werden. Die Plattenwellen wiederum strahlen unter einem definierten Winkel Schall ab, der durch das umgebende Medium propagiert. Eine entsprechende Auswertung der zurückgekoppelten Wellen, die durch Teilreflektionen von einem Hindernis hervorgerufen werden, ermöglicht die Realisierung einer Abstandsmessfunktionalität. Auf ähnliche Weise können auch Wellen, die durch ein sich bewegendes Medium propagieren, analysiert werden, um daraus Rückschlüsse auf die Durchflussmenge zu ziehen.Neben dem Herstellungsprozess einer Demonstratorstruktur mit integriertem piezokeramischen Wandlerarray wird im vorliegenden Manuskript die experimentelle Erfassung der abgestrahlten Ultraschallwellen behandelt. Hierfür wurde mit einer Messvorrichtung punktweise das von der Versuchsplatte abgestrahlte Schallfeld ermittelt. Im Rahmen der anschließenden Visualisierung können die Betrachtungsebenen räumlich und zeitlich frei gewählt werden. Ein Vergleich der experimentell ermittelten Schalldruckverteilungen mit den Simulationsergebnissen zeigt eine gute Übereinstimmung. Die Abstrahlung von gerichteten Ultraschallwellen in Luft durch ein werkstoffintegriertes Piezowandler-Array konnte somit experimentell nachgewiesen werden.},
author = {Winkler, Anja and Dannemann, Martin and Holeczek, Klaudiusz and Starke, Eric and Modler, Niels and Weiß, Manuel and Rupitsch, Stefan},
booktitle = {DAGA 2017 - 43. Jahrestagung für Akustik},
date = {2017-03-06/2017-03-09},
faupublication = {yes},
isbn = {978-3-939296-12-6},
pages = {452 - 455},
peerreviewed = {unknown},
title = {{Experimentelle} und numerische {Untersuchungen} von textilverstärkten thermoplastischen {Verbundwerkstoffen} mit eingebetteten piezoelektrischen {Sensor}-{Aktor}-{Arrays} hinsichtlich der gerichteten {Abstrahlung} von akustischen {Wellen}},
venue = {Kiel},
year = {2017}
}
@article{faucris.313369491,
abstract = {The integration of a passive elastic element in series between a motor and its load is popular in many human–robot interaction scenarios. By virtually imposing elastic behavior on the motor, an impedance control can act as a second stiffness to such an actuator. In this study, we investigated how participants perceived the different stiffness settings in a series elastic actuator by measuring the Just Noticeable Difference (JND) of the real stiffness of the elastic element and the virtual stiffness introduced by impedance control. We conducted a user study during which participants interacted with an impedance-controlled Series Elastic Actuator through a lever. During the user study, we varied the real stiffness of the elastic element and the virtual stiffness. We found that participants seem to perceive both the virtual stiffness and the real stiffness in the same way and in accordance to Weber’s law, which states that the stiffness JND is always equal to a fraction of the initial stiffness. Following these findings, we concluded that the impedance controller can implement an effective virtual stiffness with a behavior comparable to a real torsional spring. Therefore, a system combining real and virtual stiffness can simulate a single combined stiffness for a user interacting with it.},
author = {Velasco Guillen, Rodrigo Jose and Schofer, Felix and Bliek, Adna and Beckerle, Philipp},
doi = {10.3390/act12100378},
faupublication = {yes},
journal = {Actuators},
keywords = {just noticeable difference; impedance control; elastic actuation; psychophysics},
peerreviewed = {Yes},
title = {{Exploring} the {Just} {Noticeable} {Interaction} {Stiffness} {Differences} of an {Impedance}-{Controlled} {Series} {Elastic} {Actuator}},
url = {https://www.mdpi.com/2076-0825/12/10/378},
volume = {12},
year = {2023}
}
@article{faucris.114284764,
abstract = {This contribution presents a method for extracting spatial acoustic wave packet features from ultrasonic sound fields by exploiting a modified Hough transform. In ultrasound-based flow measurement systems, the fluid angle is defined as the angle under which the acoustic waves propagate with respect to the flow direction of the streaming fluid. This angle is a feature of the ultrasonic wave and is crucial for the exact calculation of the volume flow. With the proposed method, the angle can be determined reliably with an accuracy better 0: 1 from a spatially discretized sound pressure distribution that was measured or simulated. Furthermore, it allows for identifying the wave packet's wavelengths between neighboring wavefronts. The method is independent of the transducer design (i.e., angle beam or normal incidence). It is first verified and then applied to both simulated and measured data.},
author = {Ploß, Peter and Rupitsch, Stefan and Lerch, Reinhard},
doi = {10.1109/JSEN.2014.2311160},
faupublication = {yes},
journal = {IEEE Sensors Journal},
keywords = {Feature extraction;Hough transform;image processing;ultrasonic flow measurement;wavefront orientation},
pages = {2389-2395},
peerreviewed = {Yes},
title = {{Extraction} of {Spatial} {Ultrasonic} {Wave} {Packet} {Features} by {Exploiting} a {Modified} {Hough} {Transform}},
volume = {14},
year = {2014}
}
@article{faucris.261406888,
author = {Cansev, Mehmet Ege and Nordheimer, Daniel and Kirchner, Elsa Andrea and Beckerle, Philipp},
doi = {10.3389/fnbot.2021.661207},
faupublication = {yes},
journal = {Frontiers in Neurorobotics},
peerreviewed = {Yes},
title = {{Feel}-{Good} {Requirements}: {Neurophysiological} and {Psychological} {Design} {Criteria} of {Affective} {Touch} for ({Assistive}) {Robots}},
year = {2021}
}
@inproceedings{faucris.123114464,
author = {Hochradel, Klaus and Dorsch, Philipp and Häcker, Timm and Sutor, Alexander and Lerch, Reinhard},
booktitle = {DAGA - 42. Jahrestagung für Akustik},
date = {2016-03-14/2016-03-17},
faupublication = {yes},
keywords = {Microphone Array, Stereo Camera, Calibration},
peerreviewed = {unknown},
title = {{Fehlerbetrachtung} und {Kalibrierung} eines portablen {Mikrofonarrays} zur multilateralen {Ortung} von {Ultraschall}-{Fledermausrufen}},
venue = {Aachen},
year = {2016}
}
@inproceedings{faucris.114011964,
abstract = {The global demand for MEMS pressure sensors is constantly increasing. Usually, the piezoresistive
or the capacitive effect is exploited in such devices. However, it has already been shown that
sensors based on the inverse-magnetostrictive (Villari) effect feature a remarkable sensitivity while
overcoming drawbacks of the established principles like temperature-instability and non-linearity. Although simulations are crucial for the further development and optimization, simulations
incorporating the magnetostrictive and the inverse-magnetostrictive effect in such devices have
been missing until now. In this contribution, we present an iterative FE-scheme using VSM-
measurements to consider the stress-dependent permeability of the magnetostrictive layers of such
sensors. With this approach, the dimensions of the single layers are optimized to achieve maximum
sensitivity.},
author = {Löffler, Michael and Nierla, Michael and Kadur, Madlen and Sutor, Alexander and Lerch, Reinhard},
booktitle = {Abstract Book},
date = {2016-01-11/2016-01-15},
editor = {AIP, IEEE},
faupublication = {yes},
keywords = {Magnetostriction; inverse-magnetostrictive effect; Finite Element simulation; MEMS pressure sensor},
pages = {440},
peerreviewed = {unknown},
title = {{FEM}-based optimization of an inverse-magnetostrictive pressure sensor},
venue = {San Diego, CA},
year = {2016}
}
@article{faucris.201352677,
abstract = {We present a system simulation approach for piezoelectric vibration
energy harvesting devices. Accurate modeling of the electromechanical
structure is achieved by the finite element method. For consideration of
power electronic circuits as a means of energy extraction, the finite
element model is iteratively coupled to electric circuits via Simulink.
The high computational cost of conventional finite element calculations
is overcome by a specialized modal truncation method for general linear
piezoelectric structures. In doing so, the simulation approach allows
efficient prediction of mechanical quantities (e.g. displacements,
stresses) as well as electric potentials in the continuum under the
influence of arbitrary electrical circuits. Several examples are studied
to validate the truncation approach against analytical models and full
finite element models. The applicability of the method is demonstrated
for a piezoelectric vibration energy harvester in conjunction with a
power electronic circui},
author = {Gedeon, Dominik and Rupitsch, Stefan},
doi = {10.1177/1045389X17733328},
faupublication = {yes},
journal = {Journal of Intelligent Material Systems and Structures},
keywords = {Piezoelectric energy harvesting; power electronics; numerical simulation; finite element method; Simulink; model order reduction},
pages = {1333-1347},
peerreviewed = {Yes},
title = {{Finite} {Element} {Based} {System} {Simulation} for {Piezoelectric} {Vibration} {Energy} {Harvesting} {Devices}},
volume = {29},
year = {2018}
}
@article{faucris.114301924,
abstract = {For the numerical simulation of non-linear piezoelectric material behavior, we use a constitutive relation that is based on a decomposition of the physical quantities dielectric displacement and mechanical strain into a reversible and an irreversible part. Therein, we set the irreversible part of the dielectric displacement equal to the irreversible electric polarization and express the irreversible mechanical strain by a polynomial ansatz of the irreversible electric polarization. The reversible parts of mechanical strain and dielectric displacement are further described by the linear piezoelectric constitutive law. We apply a Preisach hysteresis operator to compute the irreversible polarization from the history of the driving electric field. Furthermore, the entries of the piezoelectric modulus tensor are assumed to be functions of the electric polarization. To efficiently solve the non-linear system of partial differential equations, we have developed a quasi-Newton scheme and use the finite element (FE) method for the numerical solution. This FE scheme has been applied to numerically calculate the dynamic behavior of a piezoelectric disc and a stack actuator. The obtained results compare well to measured data.},
author = {Kaltenbacher, M. and Kaltenbacher, B. and Hegewald, Thomas and Lerch, Reinhard},
doi = {10.1177/1045389X10366319},
faupublication = {yes},
journal = {Journal of Intelligent Material Systems and Structures},
keywords = {piezoelectric actuators;ferroelectric hysteresis;finite element method;quasi-Newton scheme},
pages = {773-785},
peerreviewed = {Yes},
title = {{Finite} {Element} {Formulation} for {Ferroelectric} {Hysteresis} of {Piezoelectric} {Materials}},
volume = {21},
year = {2010}
}
@inproceedings{faucris.245365959,
address = {31515 Wunstorf, Germany},
author = {Gedeon, Dominik and Rupitsch, Stefan},
booktitle = {SMSI 2020 - Sensors and Instrumentation},
date = {2020-06-25/2020-06-25},
doi = {10.5162/SMSI2020/A3.2},
editor = {AMA Service GmbH, Von-Münchhausen-Str. 49, 31515 Wunstorf, Germany},
faupublication = {yes},
pages = {61--62},
peerreviewed = {unknown},
publisher = {AMA Service GmbH},
title = {{Flexible} {Equivalent} {Circuit} {Modeling} for {Piezoelectric} {Vibration} {Energy} {Harvesters}},
venue = {Nürnberg},
year = {2020}
}
@article{faucris.117644164,
author = {Becker, Stefan and Kniesburges, Stefan and Müller, Stefan and Delgado, Antonio and Link, Gerhard and Kaltenbacher, Manfred and Döllinger, Michael},
doi = {10.1121/1.3068444},
faupublication = {yes},
journal = {Journal of the Acoustical Society of America},
note = {UnivIS-Import:2015-03-09:Pub.2009.tech.ITC.stmmec.flowst},
pages = {1351-1361},
peerreviewed = {Yes},
title = {{Flow}-structure-acoustic interaction in a human voice model},
url = {http://asadl.org/jasa/resource/1/jasman/v125/i3/p1351{\_}s1},
volume = {125},
year = {2009}
}
@incollection{faucris.120589084,
abstract = {A coupled simulation approach for fluid-structure-acoustic interactions is presented, which considers both the flow-induced sound and the sound due to structural vibrations. The proposed computation scheme is based on a partitioned approach that uses different simulation codes for the flow simulation and the structural and acoustic computations. The flow simulation is done by an in-house finite-volume code solving the incompressible Navier- Stokes equations in space and time. For the structural mechanics computations, an in-house finite-element multi- physics code is applied, which is also able to solve the acoustic wave equation describing the wave propagation to the far field. An implicit coupling scheme with sub-iterations in each time step is employed for fluid-structure interaction. The computation of the aeroacoustic sound is based on Lighthill’s theory. The structural-acoustic coupling is realized by applying appropriate boundary conditions to the acoustic wave equation. The above-described methodology is applied to a simplified model of a car underbody. The acoustic field due to the interaction of a thin, flexible plate representing coverings of the car underbody and a turbulent flow is investigated. The flexible plate is part of an otherwise rigid wall that is overflown by air. To model obstacles typically found at real car underbodies, a square cylinder is placed upstream of the flexible plate. The Reynolds number of the flow based on the free stream veloctiy and the obstacle height is 26 000.},
author = {Uffinger, Thomas and Schäfer, Frank and Becker, Stefan and Grabinger, Jens and Kaltenbacher, Manfred},
booktitle = {International Workshop on Fluid-Structure Interaction - Theory, Numerics and Applications},
editor = {Meister A, Hartmann S, Schäfer M, Turek S},
faupublication = {yes},
isbn = {978-3-89958-666-4},
pages = {253-264},
peerreviewed = {Yes},
publisher = {Kassel University Press},
title = {{Fluid}-{Structure}-{Acoustic} {Interaction} of a {Thin}, {Flexible} {Plate} in the {Wake} of a {Wall} {Mounted} {Square} {Cylinder}},
year = {2009}
}
@article{faucris.121048884,
abstract = {The acoustic field resulting from the interaction of a thin flexible structure with a turbulent flow was investigated both numerically and experimentally. Two different model configurations were considered: in one a flexible plate acted as a moving wall in a turbulent boundary layer, and in the other the flexible plate was located in the wake of a square cylinder. The fully coupled simulation of the fluid-structure-acoustics interaction was based on a partitioned approach employing two different simulation codes: a finite-volume flow solver of second-order accuracy in space and time and a finite-element structural-mechanics and acoustics solver. A code coupling interface was used for the exchange of data between the different discretizations. The experiments were performed in an acoustic wind tunnel employing microphone measurements of the sound pressure level. Detailed flow measurements were c arried out using laser Doppler anemometry and three-component hot-wire anemometry. The flow-induced vibration of the flexible structure was measured with a laser-scanning vibrometer. Experimental and numerical results characterizing the flow field, the structural vibration, and the generated sound are presented.},
author = {Schäfer, Frank and Müller, Stefan and Uffinger, Thomas and Becker, Stefan and Grabinger, Jens and Kaltenbacher, Manfred},
doi = {10.2514/1.40344},
faupublication = {yes},
journal = {Aiaa Journal},
note = {UnivIS-Import:2015-04-14:Pub.2009.tech.ITC.stmmec.fluids},
pages = {738-748},
peerreviewed = {Yes},
title = {{Fluid}-structure-acoustics interaction of the flow past a thin flexible structure},
volume = {48},
year = {2009}
}
@article{faucris.287855390,
author = {Beckerle, Philipp and Hao, Chenxu and Haeufle, Daniel F. B. and Russwinkel, Nele},
doi = {10.3389/feduc.2022.1096111},
faupublication = {yes},
journal = {Frontiers in Education},
note = {CRIS-Team WoS Importer:2023-01-20},
peerreviewed = {unknown},
title = {{Four} considerations on interdisciplinary learning at the boundaries of human and engineering sciences},
volume = {7},
year = {2022}
}
@inproceedings{faucris.123200924,
author = {Ploß, Peter and Rupitsch, Stefan and Kroh, Patrick and Lerch, Reinhard},
booktitle = {Sensors and Measuring Systems 2014; 17. ITG/GMA Symposium},
date = {2014-06-03/2014-06-04},
faupublication = {yes},
peerreviewed = {unknown},
title = {{Frequency} {Dependent} {Sound} {Radiation} of {Ultrasonic} {Wedge} {Transducers}},
venue = {Nürnberg},
year = {2014}
}
@inproceedings{faucris.313346475,
abstract = {Teleoperated robots can safely explore remote or unknown locations, render help in hazardous environments, or lighten the load for rural healthcare providers. Unfortunately, many existing frameworks are either expensive, non-portable, or require complex room preparation. Therefore, a simple, flexible, portable, and low-cost teleoperation system based on optical motion tracking with fiducial markers for robotic arm systems is presented. Interfaces to wear the optical markers on the operator’s body and an algorithm to increase robustness by switching between multiple markers have been developed.
2+-mediated force were largely unaffected. Mutant single fibers showed tendencies towards faster unloaded shortening over wild type fibers. Effects of aging seen in the wild type appeared earlier in the mutant desmin fibers. Our single-fiber experiments, free of extracellular matrix, suggest that compromised muscle biomechanics is not exclusively attributed to fibrosis but also originates from an impaired intermediate filament network.},
author = {Pollmann, Charlotte and Haug, Michael and Reischl, Barbara and Prölß, Gerhard and Pöschel, Thorsten and Rupitsch, Stefan and Clemen, Christoph S. and Schröder, Rolf and Friedrich, Oliver},
doi = {10.3390/ijms21155501},
faupublication = {yes},
journal = {International Journal of Molecular Sciences},
keywords = {Biomechatronics; Desminopathy; R349P desmin; Single fibers; Skeletal muscle},
note = {CRIS-Team Scopus Importer:2020-08-14},
pages = {1-18},
peerreviewed = {Yes},
title = {{Growing} old too early: {Skeletal} muscle single fiber biomechanics in ageing r349p desmin knock-in mice using the myorobot technology},
volume = {21},
year = {2020}
}
@article{faucris.277143768,
abstract = {Magnetic Drug Targeting (MDT) is a cancer treatment technique that enables a local chemotherapy. In MDT, chemotherapeutic drugs are bound to magnetic nanoparticles and are accumulated in the tumor area by means of an external magnetic field. Unfortunately, a single magnet can only generate a pulling magnetic force. However, in some applications a pushing force on the nanoparticles could be advantageous. One way to realize pushing forces is to exploit the acoustic radiation force based on the nonlinearity of sound propagation in fluid media generated by a high intensity focused ultrasonic transducer. In this context, we built a test setup was built to investigate the utility of High Intensity Focused Ultrasound (HIFU) to generate a pushing force on the magnetic nanoparticles. The results show that the acoustic radiation force can be employed for particle guidance to achieve concentration differences similar to those obtained by using an electromagnet.},
author = {George, Benedikt and Fink, Michael and Ermert, Helmut and Rupitsch, Stefan and Lyer, Stefan and Alexiou, Christoph},
doi = {10.1515/cdbme-2019-0148},
faupublication = {yes},
journal = {Current Directions in Biomedical Engineering},
keywords = {acoustic radiation force; drug targeting; nanoparticles; Ultrasound},
note = {CRIS-Team Scopus Importer:2022-06-27},
pages = {589-592},
peerreviewed = {Yes},
title = {{Guiding} and {Accumulation} of {Magnetic} {Nanoparticles} {Employing} {High} {Intensity} {Focused} {Ultrasound} for {Drug} {Targeting} {Applications}},
volume = {5},
year = {2019}
}
@inproceedings{faucris.227845888,
author = {George, Benedikt and Fink, Michael and Rupitsch, Stefan and Ermert, Helmut and Alexiou, Christoph and Lyer, Stefan},
booktitle = {Current Directions in Biomedical Engineering 2019},
date = {2019-09-25/2019-09-26},
doi = {10.1515/cdbme-2019-0148},
faupublication = {yes},
peerreviewed = {unknown},
title = {{Guiding} and {Accumulation} of {Magnetic} {Nanoparticles} {Employing} {High} {Intensity} {Focused} {Ultrasound} for {Drug} {Targeting} {Applications}},
venue = {Frankfurt},
year = {2019}
}
@misc{faucris.117350024,
author = {Sutor, Alexander and Albach, Thorsten and Lerch, Reinhard and Weidner, T and Weistenhöfer, Ch},
faupublication = {yes},
peerreviewed = {automatic},
title = {{Hearing} {Device} with a {Sound} {Transducer} and {Method} for {Producing} a {Sound} {Transducer}},
year = {2010}
}
@inproceedings{faucris.122252064,
author = {Weiß, Manuel and Rupitsch, Stefan and Lerch, Reinhard},
booktitle = {2016 Joint IEEE ISAF/ECAPD/PFM},
date = {2016-08-21/2016-08-25},
doi = {10.1109/ISAF.2016.7819735},
faupublication = {yes},
peerreviewed = {unknown},
title = {{Homogenization} and characterization of piezoelectric stack actuators by means of the inverse method},
venue = {Darmstadt},
year = {2016}
}
@misc{faucris.117350244,
author = {Sutor, Alexander and Albach, Thorsten and Lerch, Reinhard and Weidner, T and Weistenhöfer, Ch},
faupublication = {yes},
peerreviewed = {automatic},
title = {{Hörvorrichtung} mit einem {Schallwandler} und {Verfahren} zum {Herstellen} eines {Schallwandlers}},
year = {2010}
}
@incollection{faucris.265333126,
abstract = {To support human motions, wearable robots tightly interact with their human users. Besides demanding for functional assistance, user experience is of paramount importance. Remarkably, both aspects are subject to inter-individual differences and, hence, call for personalized solutions. This paper outlines how to address this challenge combining appropriate design methods, human-in-the-loop experiments, and cognitive modeling. Emphasis is put on the capabilities of the methods towards patient-specific solutions offline during design and online during operation.},
author = {Beckerle, Philipp},
doi = {10.1007/978-3-030-70316-5{\_}15},
faupublication = {yes},
note = {CRIS-Team Scopus Importer:2021-10-22},
pages = {91-95},
peerreviewed = {unknown},
publisher = {Springer Science and Business Media Deutschland GmbH},
series = {Biosystems and Biorobotics},
title = {{Human}-{Centered} {Approaches} for {Patient}-{Specific} {Wearable} {Robots}},
volume = {28},
year = {2022}
}
@article{faucris.288303845,
abstract = {This article presents a systematic review on wearable robotic devices that use human-in-the-loop optimization (HILO) strategies to improve human-robot interaction. A total of 46 HILO studies were identified and divided into upper and lower limb robotic devices. The main aspects from HILO were identified, reviewed, and classified in four areas: 1) human-machine systems; 2) optimization methods; 3) control strategies; and 4) experimental protocols. A variety of objective functions (physiological, biomechanical, and subjective), optimization strategies, and optimized control parameters configurations used in different control strategies are presented and analyzed. An overview of experimental protocols is provided, including metrics, tasks, and conditions tested. Moreover, the relevance given to training or adaptation periods was explored. We outline an HILO framework that includes current wearable robots, optimization strategies, objective functions, control strategies, and experimental protocols. We conclude by highlighting current research gaps and defining future directions to improve the development of advanced HILO strategies in upper and lower limb wearable robots.},
author = {Diaz, Maria Alejandra and Voß, Matthias and Dillen, Arnau and Tassignon, Bruno and Flynn, Louis and Geeroms, Joost and Meeusen, Romain and Verstraten, Tom and Babic, Jan and Beckerle, Philipp and De Pauw, Kevin},
doi = {10.1109/TCYB.2022.3224895},
faupublication = {yes},
journal = {IEEE Transactions on Cybernetics},
note = {CRIS-Team WoS Importer:2023-01-27},
peerreviewed = {Yes},
title = {{Human}-in-the-{Loop} {Optimization} of {Wearable} {Robotic} {Devices} to {Improve} {Human}-{Robot} {Interaction}: {A} {Systematic} {Review}},
year = {2022}
}
@article{faucris.285405623,
abstract = {Human body experience is remarkably flexible, which enables us to integrate passive tools as well as intelligent robotic devices into our body representation. Accordingly, it can serve as a role model to make (assistive) robots interact seamlessly with their users or to provide (humanoid) robots with a human-like self-perception and behavior generation. This article discusses the potential of understanding human body experience and applying it to robotics. Particular focus is set on how to use artificial intelligence techniques and create intelligent artificial agents from insights about human body experience. The discussion is based on a summary of the author’s habilitation thesis and combines theoretical and experimental perspectives from psychology, cognitive science and neuroscience as well as computer science, engineering, and artificial intelligence. From this, it derives directions for future developments towards creating artificial body intelligence with human-like capabilities.},
author = {Beckerle, Philipp},
doi = {10.1007/s13218-022-00779-1},
faupublication = {yes},
journal = {Künstliche Intelligenz},
keywords = {Body experience; Body intelligence; Cognitive models; Human-robot interaction},
note = {CRIS-Team Scopus Importer:2022-11-18},
peerreviewed = {Yes},
title = {{Human}-{Robot} {Body} {Experience}: {An} {Artificial} {Intelligence} {Perspective}},
year = {2022}
}
@article{faucris.114010644,
abstract = {We present a semi-numerical simulation method called SIRFEM, which enables the efficient prediction of high frequency transducer outputs. In particular, this is important for acoustic microscopy where the specimen under investigation is immersed in a coupling fluid. Conventional Finite Element (FE) simulations for such applications would consume too much computational power due to the required spatial and temporal discretization, especially for the coupling fluid between ultrasonic transducer and specimen. However, FE simulations are in most cases essential to consider the mode conversion at and inside the solid specimen as well as the wave propagation in its interior. SIRFEM reduces the computational effort of pure FE simulations by treating only the solid specimen and a small part of the fluid layer with FE. The propagation in the coupling fluid from transducer to specimen and back is processed by the so-called spatial impulse response (SIR). Through this hybrid approach, the number of elements as well as the number of time steps for the FE simulation can be reduced significantly, as it is presented for an axis-symmetric setup. Three B-mode images of a plane 2-D setup — computed at a transducer center frequency of 20 MHz — show that SIRFEM is, furthermore, able to predict reflections at inner structures as well as multiple reflections between those structures and the specimen’s surface. For the purpose of a pure 2-D setup, the spatial impulse response of a curved-line transducer is derived and compared to the response function of a cylindrically focused aperture of negligible extend in the third spatial dimension.},
author = {Nierla, Michael and Rupitsch, Stefan},
doi = {10.1109/TUFFC.2015.2510419},
faupublication = {yes},
journal = {IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control},
keywords = {Spatial Impulse Response; Finite Element Method; Pulse-Echo; Ultrasound; Microscopic Imaging},
pages = {275-289},
peerreviewed = {Yes},
title = {{Hybrid} {Semi}-numerical {Simulation} {Scheme} to {Predict} {Transducer} {Outputs} of {Acoustic} {Microscopes}},
volume = {63},
year = {2016}
}
@inproceedings{faucris.114021424,
author = {Löffler, Michael and Kremer, Ramona and Sutor, Alexander and Lerch, Reinhard},
booktitle = {Book of Abstracts},
date = {2014-11-03/2014-11-07},
faupublication = {yes},
peerreviewed = {No},
title = {{Hysteresis} of the resonance frequency of magnetostrictive bending cantilevers},
venue = {Honolulu},
year = {2014}
}
@article{faucris.114013724,
abstract = {Magnetostrictive bending cantilevers are applicable for wirelessly measuring physical quantities such as pressure and strain. Exploiting the ΔE-effect, the resonance frequency of the cantilevers is shifted because of a change in the magnetic biasing field. The biasing field, in turn, depends on the applied pressure or strain, respectively. With a view to the application as a reliable sensor, maximum sensitivity but minimum hysteresis in the biasing field/resonance frequency dependence is preferred. In this contribution, monomorph bending cantilevers fabricated using magnetostrictive FeCoV and Metglas 2605SA1 are investigated regarding their applicability for future sensors. For this purpose, the biasing field-dependent polarization of the magnetostrictive materials and bending of the cantilevers are determined. Furthermore, a setup to magnetically bias the cantilevers and determine the bending resonance frequency is presented. Here, the resonance frequency is identified by measuring the impulse response employing a laser Doppler vibrometer. The measurement results reveal that cantilevers made of FeCoV possess a distinct hysteretic behaviour at low magnetic biasing field magnitudes. This is ascribed to the polarization and bending hysteresis. Cantilevers fabricated using Metglas 2605SA1 feature a lower resonance frequency shift compared to cantilevers with FeCoV, which would result in a lower sensitivity of the sensor. However, their resonance frequency hysteresis is almost negligible.},
author = {Löffler, Michael and Kremer, Ramona and Sutor, Alexander and Lerch, Reinhard},
doi = {10.1063/1.4916162},
faupublication = {yes},
journal = {Journal of Applied Physics},
peerreviewed = {Yes},
title = {{Hysteresis} of the resonance frequency of magnetostrictive bending cantilevers},
volume = {117},
year = {2015}
}
@inproceedings{faucris.117348264,
author = {Sutor, Alexander and Bi, Shasha and Lerch, Reinhard},
booktitle = {Proceedings of INTERMAG2014},
faupublication = {yes},
pages = {2254-2256},
peerreviewed = {unknown},
title = {{Identification} and {Verification} of a {Preisach} {Based} {Vector} {Model} for {Ferromagnetic} {Materials}},
year = {2014}
}
@article{faucris.113998984,
abstract = {In many applications of ferromagnetic materials concerning sensors and actuators, magnetic fields are rotating. In order to precisely describe the behavior of ferromagnetic materials in rotating magnetic fields, vector hysteresis models are necessary. Therefore, much effort is being put into the development of efficient vector models. For the reason of computational efficiency, models have been developed that differ from the Preisach approach and are for example based on rotationally coupled step functions. We have proposed a very efficient Preisach-based model before, which we called the rotational vector Preisach model. In this paper, we propose an extension of the rotational switching function, which improves the model characteristics for arbitrary H-field trajectories. We also introduce a set of special vectorial minor loops for the general validation and comparison of vector models. We apply those H-field trajectories to isotropic materials such as sputtered FeCo thin films as used in micromechanical systems. The vectorial minor loops can readily be utilized to evaluate the model output, and the results agree well with vectorial measurements.},
author = {Sutor, Alexander and Bi, Shasha and Lerch, Reinhard},
doi = {10.1007/s00339-014-8817-1},
faupublication = {yes},
journal = {Applied Physics A-Materials Science & Processing},
pages = {939-944},
peerreviewed = {Yes},
title = {{Identification} and verification of a {Preisach}-based vector model for ferromagnetic materials},
volume = {118},
year = {2015}
}
@inproceedings{faucris.117348044,
author = {Sutor, Alexander and Bi, Shasha and Lerch, Reinhard},
booktitle = {ITG-Fachbericht Sensoren und Messsysteme 2014},
faupublication = {yes},
isbn = {978-3-8007-3622-5},
peerreviewed = {unknown},
title = {{Identification} and {Verification} of a {Vector} {Model} for {Ferroic} {Materials}},
year = {2014}
}
@inproceedings{faucris.108560364,
abstract = {Ultrasound-based flow measurement relies on the proper knowledge of the angle under which the acoustic waves propagate with respect to the flow direction of the streaming fluid. We present a novel image processing approach for the identification of the wavefronts' orientation by exploiting a modified Hough transform. The spatially discretized sound pressure amplitude of measurement/simulation data is utilized as a weighting function for the Hough transform. It is shown that the angle and position of a wavefront can be estimated with subpixel accuracy, where the size of a pixel depends on the data's spatial resolution. This is achieved by incorporating a least-squares algorithm, fitting a 2D Gaussian function to the Hough parameter plane and thus improving the accuracy of the detected wavefront properties. (C) 2012 Elsevier Ltd....Selection and/or peer-review under responsibility of the Symposium Cracoviense Sp. z.o.o.},
author = {Ploß, Peter and Rupitsch, Stefan and Fröhlich, T. and Lerch, Reinhard},
doi = {10.1016/j.proeng.2012.09.122},
faupublication = {yes},
keywords = {flow measurement;ultrasound;wavefront orientation;Hough transform;image processing;subpixel accuracy},
month = {Jan},
pages = {216-219},
peerreviewed = {unknown},
publisher = {Elsevier BV},
title = {{Identification} of {Acoustic} {Wave} {Orientation} for {Ultrasound}-{Based} {Flow} {Measurement} by {Exploiting} the {Hough} {Transform}},
volume = {47},
year = {2012}
}
@inproceedings{faucris.124065084,
author = {Rupitsch, Stefan and Sutor, Alexander and Ilg, Jürgen and Lerch, Reinhard},
booktitle = {Proceedings of the IEEE Ultrasonic Symposium},
faupublication = {yes},
pages = {1214-1217},
peerreviewed = {No},
title = {{Identification} {Procedure} for {Real} and {Imaginary} {Material} {Parameters} of {Piezoceramic} {Materials}},
year = {2010}
}
@inproceedings{faucris.108561244,
abstract = {The impact of sensor design on the inspection of planar electronic devices by capacitive coupling is investigated. To allow for the inspection of electrically isolated conductive parts of devices, such as partly processed flat panel displays or printed electronic circuits, new sensor designs have been developed and are evaluated with the help of finite element simulations. The analysis of the simulation results shows that a clear detection of the conductive parts is achieved if the sensor geometry enforces a non-uniform electrical field distribution in the range of the sensor area. By studying the capacitive coupling to the individual parts of the sensors, design rules for sensor electrode and shielding geometry are deduced. (C) 2011 Published by Elsevier Ltd.},
author = {Koerdel, M. and Alatas, F. and Schick, A. and Rupitsch, Stefan and Lerch, Reinhard},
doi = {10.1016/j.proeng.2011.12.103},
faupublication = {yes},
keywords = {capacitive coupling;contactless inspection;finite element (FE) simulation;flat panel display (FPD);planar electronic device;sensor design},
month = {Jan},
peerreviewed = {unknown},
publisher = {Elsevier BV},
title = {{Impact} of sensor design on the contactless inspection of planar electronic devices by capacitive coupling},
volume = {25},
year = {2011}
}
@article{faucris.114302584,
abstract = {This paper deals with the temperature dependence of the electrical impedance of piezoceramic transducers. The behavior under thermal loads is investigated for bulk ceramics and composite structures where the piezoceramics are integrated into passive materials. According to these identified dependencies, temperature sensing through the piezoceramics impedance is realized using a polynomial fitting method. A creep operator and a lead filter are introduced to consider the time-dependent behavior of the electrical impedance. The presented approach is applied to a commercially available air ultrasound transducer. The accuracy of the measurement method is investigated for an arbitrary temperature profile yielding +/- 4.5 degrees C. The presented method can be utilized for additionally sensing temperature in devices with integrated piezoceramic transducers, especially ultrasound transducers or in structural health-monitoring applications.},
author = {Ilg, Jürgen and Rupitsch, Stefan and Lerch, Reinhard},
doi = {10.1109/JSEN.2013.2256121},
faupublication = {yes},
journal = {IEEE Sensors Journal},
keywords = {Piezoceramics;temperature dependence;impedance measurement;temperature sensors;hysteresis modelling},
pages = {2442-2449},
peerreviewed = {Yes},
title = {{Impedance}-{Based} {Temperature} {Sensing} {With} {Piezoceramic} {Devices}},
volume = {13},
year = {2013}
}
@article{faucris.216710034,
abstract = {We present a two-stage energy extraction circuit for a piezoelectric energy harvester, powering an asset-tracking system. Exploiting accelerations generated by many logistic transport devices, e.g., pushcarts, forklifts, assembly belts or cars, we are able to harvest sufficient electrical energy to transmit radio signals, which will allow to track an object when it is moving. Accelerations in logistic applications are non-sinusoidal and lead to high open-circuit voltages, which demand a special adaption of the energy extraction network. We evaluate the performance of several state-of-the-art energy extraction networks and compare those to the performance of our two-stage approach under various excitation conditions. By using the proposed energy extraction circuit, the transmission rate could be increased from four to six transmissions per second for sinusoidal excitations with an open-circuit-voltage of 60V. In the practical use-case, the two-stage energy extraction network performs more than two times better compared to the one-stage and synchronized switching harvesting with inductor approach.},
author = {Dorsch, Philipp and Bartsch, Toni and Hubert, Florian and Milosiu, Heinrich and Rupitsch, Stefan},
doi = {10.3390/s19061330},
faupublication = {yes},
journal = {Sensors},
note = {CRIS-Team WoS Importer:2019-04-30},
peerreviewed = {Yes},
title = {{Implementation} and {Validation} of a {Two}-{Stage} {Energy} {Extraction} {Circuit} for a {Self} {Sustained} {Asset}-{Tracking} {System}},
volume = {19},
year = {2019}
}
@article{faucris.225323830,
abstract = {Nanoparticles of poly-L-lactic acid dispersed in water and of approximately 120 nm diameter were prepared by a nanoprecipitation method followed by lyophilization together with trehalose. After rehydration, the nanodispersion was exposed to ultrasound at 835 kHz frequency and 1.8 MPa peak negative sound pressure. Substantial levels of broadband noise were surprisingly detected which are attributed to the occurance of inertial cavitation of bubbles present in the dispersion. Inertial cavitation encompasses the formation and growth of gas cavities in the rarefaction pressure cycle which collapse in the compression cycle because of the inwardly-acting inertia of the contracting gas-liquid interface. The intensity of this inertial cavitation over 600 s was similar to that produced by Optison microbubbles used as contrast agents for diagnostic ultrasound. Non-lyophilized nanodispersions produced negligible broadband noise showing that lyophilization and rehydration are requirements for broadband activity of the nanoparticles. Photon correlation spectroscopy indicates that the nanoparticles are not highly aggregated in the nanodispersion and this is supported by scanning (SEM) and transmission (TEM) electron micrographs. TEM visualized non-spherical nanoparticles with a degree of irregular, non-smooth surfaces. Although the presence of small aggregates with inter-particulate gas pockets cannot be ruled out, the inertial cavitation activity can be explained by incomplete wetting of the nanoparticle surface during rehydration of the lyophilizate. Nano-scale gas pockets may be trapped in the surface roughness of the nanoparticles and may be released and coalesce to the size required to nucleate inertial cavitation on insonation at 835 kHz/1.8 MPa.},
author = {Hiltl, Pia-Theresa and Grebner, Alexander and Fink, Michael and Rupitsch, Stefan and Ermert, Helmut and Lee, Geoffrey},
doi = {10.1038/s41598-019-48074-8},
faupublication = {yes},
journal = {Scientific Reports},
note = {CRIS-Team Scopus Importer:2019-08-30},
peerreviewed = {Yes},
title = {{Inertial} cavitation of lyophilized and rehydrated nanoparticles of poly({L}-lactic acid) at 835 {kHz} and 1.8 {MPa} ultrasound},
volume = {9},
year = {2019}
}
@inproceedings{faucris.123578884,
author = {Fink, Michael and Ermert, Helmut and Lyer, Stefan and Alexiou, Christoph},
booktitle = {Proceedings of the Ultrasonics Symposium (IUS)},
date = {2017-09-06/2017-09-09},
faupublication = {yes},
peerreviewed = {unknown},
title = {{Influence} of {Naturally} {Occurring} {Tissue} {Movements} on {Magnetomotive} {Ultrasound} {Detection} of {Iron} {Oxide} {Nanoparticles} for {Magnetic} {Drug} {Targeting}},
venue = {Washington DC},
year = {2017}
}
@inproceedings{faucris.122719784,
author = {Weiß, Sandra and Thomson, Scott and Sutor, Alexander and Rupitsch, Stefan and Lerch, Reinhard},
booktitle = {Proceedings of 6th International Conference on Biomedical Electronics and Devices (BIODEVICES) 2013},
faupublication = {yes},
pages = {108-113},
peerreviewed = {unknown},
title = {{Influence} of {Pipette} {Geometry} on the {Displacement} {Profile} of {Isotropic} {Materials} used for {Vocal} {Fold} {Modeling}},
volume = {1},
year = {2013}
}
@article{faucris.114304344,
abstract = {Piezoceramic patch transducers are integrated into aluminum components using high-pressure die casting. Expanded metal has proven suitable as a supporting structure for placing the patch transducers inside the die cavity and for stabilization during the injection of molten metal. However, difficulties arise when the transducers are positioned off the neutral axis within the wall of the casting. Numerical simulations of the die filling are performed to analyse the evolution of the integration process. The asymmetric infiltration of the supporting structure is identified as the major factor contributing to the formation of cracks and perforations inside the piezoceramic transducer. By means of measurements and numerical calculations of the electrical impedance of the transducer, a close relation is established between mechanical damage patterns observed in radiographs of the patch transducers and loss of performance.},
author = {Klassen, Alexander and Rübner, Matthias and Ilg, Jürgen and Rupitsch, Stefan and Lerch, Reinhard and Singer, Robert and Körner, Carolin},
doi = {10.1088/0964-1726/21/11/115014},
faupublication = {yes},
journal = {Smart Materials & Structures},
peerreviewed = {Yes},
title = {{Influence} of the fabrication process on the functionality of piezoceramic patch transducers embedded in aluminum die castings},
volume = {21},
year = {2012}
}
@inproceedings{faucris.313347791,
author = {Hao, Chenxu and Russwinkel, Nele and Haeufle, Daniel F. B. and Beckerle, Philipp},
booktitle = {Conference of the German Society for Cognitive Science},
faupublication = {yes},
peerreviewed = {unknown},
series = {Symposium on Cognition-centered Human-Robot Interaction},
title = {{Integrating} {Models} of {Cognitive} and {Physical} {Human}-{Robot} {Interaction}},
year = {2022}
}
@inproceedings{faucris.123026464,
address = {Chemnitz},
author = {Klassen, Alexander and Rübner, Matthias and Ilg, Jürgen and Rupitsch, Stefan and Lerch, Reinhard and Körner, Carolin and Singer, Robert},
booktitle = {Proceedings of the CRC/TR39 3rd Scientific Symposium "Integration of Active Functions into Structural Elements"},
editor = {R. Neugebauer},
faupublication = {yes},
isbn = {978-3-00-035549-3},
pages = {45-50},
peerreviewed = {unknown},
title = {{Integration} of piezoceramic sensors and actuators into structural components via high pressure die casting},
year = {2011}
}
@inproceedings{faucris.106621944,
author = {Vossiek, Martin and Eccardt, P.-C. and Magori, V. and Ermert, Helmut},
booktitle = {Konferenz-Einzelbericht: Technische Anwendungen von Fuzzy-Systemen},
faupublication = {yes},
note = {UnivIS-Import:2017-12-18:Pub.1992.tech.IE.LEH.intell},
pages = {71-80},
peerreviewed = {unknown},
title = {{Intelligente} {Sensorsignalverarbeitung} durch {Kombination} von {Fuzzy}-{Logik} und klassischer {Signalvorverarbeitung} am {Beispiel} eines {Luftultraschallsystems} zur {Platinenbestückungskontrolle}},
year = {1992}
}
@article{faucris.261406430,
author = {Cansev, Mehmet Ege and Xue, Honghu and Rottmann, Nils and Bliek, Adna and Miller, Luke E and Rueckert, Elmar and Beckerle, Philipp},
doi = {10.1002/aisy.202000247},
faupublication = {no},
journal = {Advanced Intelligent Systems},
peerreviewed = {Yes},
title = {{Interactive} {Human}–{Robot} {Skill} {Transfer}: {A} {Review} of {Learning} {Methods} and {User} {Experience}},
year = {2021}
}
@inproceedings{faucris.123032624,
author = {Heining, Martin and Sutor, Alexander and Lindenberger, Christoph and Stute, Stephanie and Buchholz, Rainer},
booktitle = {Young Algaeneers Symposium},
faupublication = {yes},
peerreviewed = {unknown},
title = {{Internal} {Illumination} of photobioreactors via {Wireless} {Light} {Emitter} – a proof of concept},
year = {2014}
}
@article{faucris.123942544,
abstract = {A novel concept for internal illumination of photobioreactors via wireless light emitters (WLEs) has been developed to increase the manageable culture volume of photosynthetic active microorganisms or cells. The illumination system is based on free suspendable light emitters, which are powered wirelessly by near-field resonant inductive coupling and, therefore, are able to illuminate a photobioreactor more homogeneously than external illumination systems. Since an intermediate frequency electromagnetic field (IF-EMF) acts inside the reactor, the impact of an IF-EMF (B = 0.95 mT, f = 178 kHz) on the green alga Chlamydomonas reinhardtii is determined. The growth rate, the achieved cell dry weight, and the maximum photosynthetic yield Y (0) are unaffected by the applied IF-EMF. Furthermore, a negative effect of the potentially occurring mechanical stress due to the suspended WLE can be excluded. A culture which is mechanically stressed by 125 WLEs per liter shows the same maximal growth rate of 2.29 day(-1) as a control culture. Finally, the comparison of an externally illuminated photobioreactor and a via WLE internally illuminated photobioreactor shows the same growth rates in the exponential growth phase. However, the growth rate in the linear phase is more than twice the rate of the externally illuminated control culture, resulting in a more than 80 % higher achieved biomass. Light profiles over the cross section of both reactor types show clearly that the internal illumination via WLE results in a more uniform light distribution and a higher average light intensity in the reactor.},
author = {Heining, Martin and Sutor, Alexander and Stute, Stephanie and Lindenberger, Christoph and Buchholz, Rainer and Buchholz, Rainer},
doi = {10.1007/s10811-014-0290-x},
faupublication = {yes},
journal = {Journal of Applied Phycology},
keywords = {Photobioreactor;Internal illumination;Wireless light emitter;Magnetic field;Wireless energy transfer;Near-field resonant inductive coupling},
pages = {59-66},
peerreviewed = {Yes},
title = {{Internal} illumination of photobioreactors via wireless light emitters: a proof of concept},
volume = {27},
year = {2015}
}
@article{faucris.124190264,
abstract = {We present an approach for characterizing the mechanical frequency dependence of solid materials (i.e., viscoelasticity). Especially plastics commonly show a viscoelastic behavior. The frequency-dependent mechanical material parameters are identified through the inverse
method, which is based on the minimization of deviations between measurements and simulation results via an iterative adjustment of the parameters. In this contribution, an adapted inverse method and the principle of the material characterization are illustrated. In addition, we compare selected viscoelastic material models and discuss the applicability of these models by means of an exemplary solid material.},
author = {Weiß, Manuel and Ilg, Jürgen and Rupitsch, Stefan and Lerch, Reinhard},
doi = {10.1515/teme-2015-0094},
faupublication = {yes},
journal = {Technisches Messen},
keywords = {Material characterization, inverse method, viscoelasticity},
pages = {123-130},
peerreviewed = {Yes},
title = {{Inverse} {Methode} zur {Charakterisierung} des mechanischen {Frequenzverhaltens} isotroper {Werkstoffe}},
volume = {83},
year = {2016}
}
@inproceedings{faucris.106527344,
author = {Weiß, Manuel and Ilg, Jürgen and Rupitsch, Stefan and Lerch, Reinhard},
booktitle = {10th International Workshop Direct and Inverse on Problems on Piezoelectricity},
date = {2014-09-21/2014-09-24},
faupublication = {yes},
peerreviewed = {unknown},
title = {{Inverse} {Method} for {Characterizing} {Material} {Parameters} of {Active} and {Passive} components},
venue = {Wien},
year = {2014}
}
@inproceedings{faucris.124057824,
author = {Weiß, Manuel and Ilg, Jürgen and Rupitsch, Stefan and Lerch, Reinhard},
booktitle = {Proceedings SENSOR 2015},
doi = {10.5162/sensor2015/A6.2},
faupublication = {yes},
isbn = {978-3-9813484-8-4},
peerreviewed = {unknown},
title = {{Inverse} {Method} for {Determining} {Material} {Parameters} of {Piezoceramics} and {Passive} {Materials}},
venue = {Nürnberg},
year = {2015}
}
@inproceedings{faucris.114181364,
author = {Weiß, Manuel and Hohlfeld, Kai and Gebhardt, Sylvia and Rupitsch, Stefan and Lerch, Reinhard and Michaelis, Alexander},
booktitle = {Leightweight Design by Integrating Functions},
faupublication = {yes},
isbn = {978-3-00-050383-2},
pages = {77-82},
peerreviewed = {unknown},
title = {{Inverse} {Method} for {Determining} piezoelectric material parameters of piezoceramic fiber composites},
venue = {Dresden},
year = {2015}
}
@inproceedings{faucris.114306324,
abstract = {In this contribution, we exploit an Inverse scheme enabling the identification of temperature dependent material parameters of piezoceramic materials as well as their electromechanical coupling factors. This information is indispensable to predict the behavior of sensors and actuators incorporating such materials. Principally, the identification procedure is based on an iterative adjustment of finite element (FE) simulations to measurements. As the results for the piezoceramic materials PIC255 and PIC155 (both fabricated from PI Ceramic) reveal, several material parameters (e. g., electric permittivities) strongly rely on temperature. However, the electromechanical coupling factors for these materials remain nearly constant in the considered temperature range - 35 degrees C to + 130 degrees C.},
author = {Rupitsch, Stefan and Ilg, Jürgen and Lerch, Reinhard},
faupublication = {yes},
keywords = {Piezoceramic materials;material parameters;coupling factors;temperature dependence;Inverse Method},
month = {Jan},
pages = {183-186},
peerreviewed = {Yes},
title = {{Inverse} {Scheme} to {Identify} the {Temperature} {Dependence} of {Electromechanical} {Coupling} {Factors} for {Piezoceramics}},
year = {2013}
}
@inproceedings{faucris.241993488,
abstract = {Increasing switching frequencies and miniaturization of switched-mode power supplies set strict requirements on the design of electromagnetic interference filters. Piezoelectric interference-suppression components are a promising new approach to improve the performance of electromagnetic interference filters. Moreover, they have the potential to reduce size, weight and cost of switched mode power supplies. However, the influence of the piezoelectric ceramic material on the filter performance has not been studied so far. As our measurement results reveal, by an appropriate choice of the ceramic material, the filter performance of a piezoelectric interference-suppression component can be improved by 40 dB in comparison to a regular Y-capacitor.},
author = {Hubert, Florian and Dorsch, Philipp and Dürbaum, Thomas and Rupitsch, Stefan},
booktitle = {PCIM Europe Conference Proceedings},
date = {2020-07-07/2020-07-08},
faupublication = {yes},
isbn = {9783800752454},
note = {CRIS-Team Scopus Importer:2020-08-28},
pages = {516-523},
peerreviewed = {unknown},
publisher = {Mesago PCIM GmbH},
title = {{Investigation} of different piezoelectric ceramics for utilization in piezoelectric {EMI} filters},
venue = {Virtual, Online},
volume = {1},
year = {2020}
}
@inproceedings{faucris.227846639,
author = {George, Benedikt and Fink, Michael and Rupitsch, Stefan and Hiltl, Pia-Theresa and Lee, Geoffrey and Ermert, Helmut},
booktitle = {Proceedings IEEE IUS 2019},
date = {2019-10-06/2019-10-09},
doi = {10.1109/ultsym.2019.8925947},
faupublication = {yes},
peerreviewed = {unknown},
title = {{Investigation} of {Inertial} {Cavitation} {Stimulation} by {Focused} {Ultrasound} on {Sonosensitive} {Nanoparticles} for {Drug} {Delivery} {Applications}},
venue = {Glasgow},
year = {2019}
}
@inproceedings{faucris.227845510,
author = {George, Benedikt and Rupitsch, Stefan and Fink, Michael and Ermert, Helmut and Hiltl, Pia-Theresa and Lee, Geoffrey},
booktitle = {Current Directions in Biomedical Engineering 2019},
date = {2019-09-25/2019-09-26},
doi = {10.1515/cdbme-2019-0147},
faupublication = {yes},
peerreviewed = {unknown},
title = {{Investigation} of the {Inertial} {Cavitation} {Activity} of {Sonosensitive} and {Biocompatible} {Nanoparticles} for {Drug} {Delivery} {Applications} {Employing} {High} {Intensity} {Focused} {Ultrasound}},
venue = {Frankfurt},
year = {2019}
}
@inproceedings{faucris.114306544,
abstract = {This contribution determines the resolution achievable by Synthetic Aperture Focusing Technique (SAFT) processing ultrasonic inspection data acquired along circular scan paths. If the inspection is conducted using a transducer with a narrow divergence angle, the lateral resolution after SAFT reconstruction becomes highly depth dependent. In Nondestructive Testing (NDT), such a configuration is typical for the ultrasonic testing of heavy rotor steel forging blanks for energy industry components, such as rotor shafts and turbine discs. There, the inspection is performed in contact mode over specimen's mantle surface with longitudinal waves. For defect classification and quantification, knowledge of the resolution is essential. The radial dependency of the resolution is determined by SAFT processing simulated far field point spread functions at different depths. The simulation results are discussed and compared with actual inspection data of turbine disc forgings containing reference reflectors and natural indications.},
author = {Fendt, Karl and Mooshofer, Hubert and Rupitsch, Stefan and Lerch, Reinhard and Ermert, Helmut},
booktitle = {Ultrasonics Symposium (IUS), 2013 IEEE International},
doi = {10.1109/ULTSYM.2013.0476},
faupublication = {yes},
month = {Jan},
pages = {1869-1872},
peerreviewed = {Yes},
title = {{Investigation} of the {Synthetic} {Aperture} {Focusing} {Technique} resolution for heavy rotor forging ultrasonic inspection},
year = {2013}
}
@inproceedings{faucris.113884584,
author = {Weiß, Manuel and Rupitsch, Stefan},
booktitle = {7th International Symposium on Piezocomposite Applications ISPA},
date = {2017-09-14/2017-09-15},
faupublication = {yes},
pages = {26},
peerreviewed = {unknown},
title = {{Investigation} on {Homogenized} {Piezoelectric} {Patch} {Transducers}},
venue = {Dresden},
year = {2017}
}
@inproceedings{faucris.114308304,
abstract = {Progress in medical ultrasound in recent years makes sonography a valuable method for early rheumatoid arthritis (RA) diagnosis today. However, detecting in ammatory processes in periarticular bones requires expert knowledge and training. 360 degrees compound imaging has already proven to increase ultrasound B-mode image quality significantly, e.g. in breast cancer imaging. Therefore an existing Ultrasound Computed Tomography (USCT) system has been modified for RA diagnosis, with respect to finger joint imaging. Well known concepts in USCT to reconstruct the speed of sound (SOS) distribution can not be applied, as the bone inhibits transmission measurements of fingers. Therefore, an image based local contrast quanti. cation method is proposed to estimate a mean SOS for the soft tissue surrounding the finger joint. Based on this estimation, ultrasound B-mode images can be corrected for refraction and TOF to yield high image quality in 360 degrees compound imaging. This method has been validated by measurements on tissue mimicking phantoms. Healthy volunteers and RA patients have been examined with the USCT system. In-vivo results show a great potential for 360 degrees compound imaging to visualize synovitis as well as bone erosion in RA of finger joints.},
author = {Koch, Andreas and Finzel, Stephanie and Kobler, Andreas and Schett, Georg and Lerch, Reinhard and Ermert, Helmut},
doi = {10.1109/ULTSYM.2012.0033},
faupublication = {yes},
keywords = {rheumatoid arthritis;ultrasound computed tomography;full angle spatial compounding;speed of sound estimation;refraction correction;nger joints;in-vivo results},
month = {Jan},
pages = {134-137},
peerreviewed = {Yes},
publisher = {IEEE SERVICE CENTER, 445 HOES LANE, PO BOX 1331, PISCATAWAY, NJ 08855-1331 USA},
title = {{In}-vivo results for rheumatoid arthritis diagnosis with a 360 degrees pulse-echo imaging system},
year = {2012}
}
@article{faucris.255631590,
abstract = {Various medical procedures make use of magnetic nanoparticles, such as Magnetic Drug Targeting (MDT), which boosts the demand for imaging modalities that are capable of in vivo visualizing this kind of particles. Magnetomotive Ultrasound is an imaging technique that can detect tissue, which is perfused by magnetic nanoparticles. In this contribution, we investigate the suitability of Magnetomotive Ultrasound to serve as a monitoring system during MDT. With the conducted measurements, it was possible for the first time to observe in vivo the accumulation of iron-oxide nanoparticles during a Magnetic Drug Targeting cancer treatment applied to a small animal (rabbit). },
author = {Fink, Michael and Rupitsch, Stefan and Ermert, Helmut and Lyer, Stefan},
doi = {10.1515/cdbme-2020-3139},
faupublication = {yes},
journal = {Current Directions in Biomedical Engineering},
keywords = {iron-oxide nanoparticles; Magnetic Drug Targeting; Magnetomotive Ultrasound; ultrasonic imaging},
note = {CRIS-Team Scopus Importer:2021-04-19},
peerreviewed = {Yes},
title = {{In} {Vivo} {Study} on {Magnetomotive} {Ultrasound} {Imaging} in the {Framework} of {Nanoparticle} based {Magnetic} {Drug} {Targeting}},
volume = {6},
year = {2020}
}
@inproceedings{faucris.123022724,
abstract = {Magnetoelectric (ME) energy harvesting devices consisting of layered magnetostrictive/piezoelectric composites exploit the large mechanical strains arising from movements inside an external magnetic field to increase the electrical power output of the piezoelectric layers. Numerical methods help to optimize the design and the efficiency of such setups. Methods based on the solution of one directly coupled equation system, however, can in general not account for the change in geometry which occurs due to the harvester's movement inside the external magnetic field. In this contribution, we present an iteratively coupled Finite Element (FE) scheme for such devices that does not only enable the coupled simulation of magnetostrictive and piezoelectric effects, but furthermore allows the consideration of changing geometrie},
author = {Nierla, Michael and Löffler, Michael and Rupitsch, Stefan},
booktitle = {Procedia Engineering - Eurosensors 2015},
date = {2015-09-06/2015-09-09},
doi = {10.1016/j.proeng.2015.08.682},
faupublication = {yes},
keywords = {Energy Harvesting; Magnetostriction; Piezoelectricity; Finite Element Method; Iterative Coupling},
pages = {496-500},
peerreviewed = {Yes},
publisher = {Elsevier BV},
title = {{Iterative} finite element scheme for magnetoelectric energy harvesters},
venue = {Freiburg},
volume = {120},
year = {2015}
}
@inproceedings{faucris.293826864,
address = {NEW YORK},
author = {Godoy, Ricardo V. and Dwivedi, Anany and Shahmohammadi, Mojtaba and Liarokapis, Minas},
booktitle = {2022 IEEE/RSJ INTERNATIONAL CONFERENCE ON INTELLIGENT ROBOTS AND SYSTEMS (IROS)},
doi = {10.1109/IROS47612.2022.9981514},
faupublication = {yes},
month = {Jan},
note = {CRIS-Team WoS Importer:2023-03-24},
pages = {6087-6094},
peerreviewed = {unknown},
publisher = {IEEE},
title = {{Lightmyography} {Based} {Decoding} of {Human} {Intention} {Using} {Temporal} {Multi}-{Channel} {Transformers}},
venue = {Kyoto, JAPAN},
year = {2022}
}
@inproceedings{faucris.315841802,
abstract = {Attempts in research to equip robotic end-effectors with tactile sensing facilitate an advanced environment perception and provide the means for dexterous interaction. Sensing at the fingertips can be realized using force sensors. In this work, we present an additively manufactured universal force-sensor offering structural integration to accomplish fast adaptation to application-specific needs. The piezoresistive sensor consists of commercially available conductive polylactic acid (PLA). Its geometry is based on rigid PLA spring elements to overcome the inherent limitations of elastomers. A curved shape increases the length of the deformation element, thus, the sensitivity, while retaining the flexibility necessary to allow for a displacement-induced change of the electrical resistance. The sensor features an additional integrated spring, which enables the adaptation of the mechanical stiffness and therefore of the measurement range. We use thread-forming screws to achieve a robust and enduring electrical connection between wires and the conductive polymer. The characterization of the sensor takes place in a universal testing machine with an applied load up to 5 N. The resistance measured gives a nearly linear characteristic and is proportional to the displacement. We obtain a sensitivity of 6.5 Ohm/N and a relative change of resistance of 6%. Low creep (0.12%) during phases with constant load reveals an advanced geometry-induced mechanical behavior. Thus, our printed piezoresistive PLA sensor demonstrates the suitability of conductive rigid materials for their tailored application as force sensors in robotics.},
author = {Latsch, Bastian and Dali, Omar Ben and Chadda, Romol and Schafer, Niklas and Altmann, Alexander A. and Grimmer, Martin and Beckerle, Philipp and Kupnik, Mario},
booktitle = {Proceedings of IEEE Sensors},
date = {2023-10-29/2023-11-01},
doi = {10.1109/SENSORS56945.2023.10325114},
faupublication = {yes},
isbn = {9798350303872},
keywords = {creep; force sensor; piezoresistive; printed; robotics; sensitivity; structural integration; tactile sensing},
note = {CRIS-Team Scopus Importer:2023-12-22},
peerreviewed = {unknown},
publisher = {Institute of Electrical and Electronics Engineers Inc.},
title = {{Low} {Creep} {3D}-{Printed} {Piezoresistive} {Force} {Sensor} for {Structural} {Integration}},
venue = {Vienna, AUT},
year = {2023}
}
@inproceedings{faucris.110135124,
abstract = {For common sensor/actuator applications in which signal data is only forwarded, ALOHA-protocol-based radio transmissions as well as full-stack radio solutions do not appear to be the most energy-efficient solutions. Thus, an own low-power and widely customizable radio solution has been developed. It is based on standard general purpose radio components and achieves high energy efficiency by use of time-controlled (TDMA) low duty-cycle transmissions. The presented solution is especially well suited to the task of periodic transmissions of measurement values. For demonstration, a sensor node has been implemented and the radio soluti performance has been evaluated.},
address = {31515 Wunstorf / Germany},
author = {Kroh, Patrick and Fink, Michael and Günther, Hans-Michael and Lerch, Reinhard},
booktitle = {Proceedings - AMA Conferences 2017 with SENSOR and IRS²},
date = {2017-05-30/2017-06-01},
doi = {10.5162/sensor2017/C6.4},
faupublication = {yes},
isbn = {978-3-9816876-4-4},
keywords = {Wireless; Sensor; Low-Power; TDMA; Standard Components},
pages = {395 - 400},
peerreviewed = {unknown},
title = {{Low}-power optimized, widely customizable, time-controlled wireless sensor/actuator data transmission with commercial off-the-shelf standard components},
venue = {Nürnberg},
year = {2017}
}
@incollection{faucris.122860584,
address = {Aachen},
author = {Sutor, Alexander and Kallwies, Jan and Lerch, Reinhard},
booktitle = {XV. Messtechnisches Symposium},
editor = {Leon FP, Beyerer J},
faupublication = {yes},
isbn = {978-3-8440-0388-8},
pages = {27-38},
peerreviewed = {unknown},
publisher = {Shaker Verlag},
title = {{Magnetische} {Vektorhysterese}: {Messtechnik} und {Modellierung}},
year = {2011}
}
@article{faucris.216964490,
abstract = {Magnetisch-induktive Durchflusssensoren zeichnen sich durch lange Wartungsintervalle aus, sind jedoch auf die Zuführung elektrischer Leistung zur Erzeugung des für die Messung benötigten magnetischen Wechselfelds angewiesen. In jüngster Zeit gibt es Bestrebungen Sensoren kabellos zu betreiben. Die Minimierung des Leistungsbedarfs des Sensors gewinnt so zunehmend an Bedeutung, um eine lange Betriebszeit des Messwertgebers sicherzustellen. In diesem Beitrag wird deshalb ein magnetisch remanentes Material hinsichtlich seines Energieeinsparpotentials für die magnetisch-induktive Durchflussmessung untersucht. Im Gegensatz zur üblichen Felderzeugung mittels Elektromagneten wird nur während der kurzen Umpolzeiträume elektrische Leistung benötigt. Danach bleibt das Magnetfeld auch ohne weitere Zuführung elektrischer Leistung konstant und kann zur Durchflussmessung herangezogen werden. Anders als beispielsweise Ferritmagnete lassen sich remanente Magnetmaterialien jedoch unter geringerem Energieaufwand umpolen, was sie für die Erzeugung magnetischer Wechselfelder prädestiniert. Wie ein Sensor auf Basis remanenter Materialien dimensioniert werden sollte, damit ein für die Messung ausreichendes Magnetfeld unter minimalen Verlusten erzeugt wird, ist eine der Kernfragen dieses Beitrags. Dazu wird ein Prototyp mithilfe eines Modells ausgelegt und messtechnisch untersucht. Die Ansteuerung des Sensors erfolgt über eine eigens entwickelte Logikschaltung. Es konnte gezeigt werden, dass die Messgenauigkeit unabhängig von der Art der Felderzeugung erhalten bleibt. Für niedrige Feldwechselraten kann der geringe Leistungsbedarf remanenter Magnetmaterialien bestätigt werden.
sure the magnetization of ferromagnetic thin-film sam-
ples subjected to mechanical stress. We present our
Vector Vibrating Sample Magnetometer and two fix-
tures that enable the adjustable bending of the ferro-
magnetic samples during the magnetization measure-
ment. The bending, in turn, results in internal stresses.
According to the magnetoelastic effect, the magneti-
zation of ferromagnetic materials depends on internal
mechanical stress. Results of two Fe 49 Co 49 V 2 samples
are shown which prove the applicability of the proposed
method.},
author = {Löffler, Michael and Piepgras, Ruben and Sutor, Alexander and Lerch, Reinhard},
booktitle = {Proceedings},
date = {2014-09-15/2014-09-17},
faupublication = {yes},
isbn = {978-92-990073-2-7},
pages = {55-59},
peerreviewed = {Yes},
title = {{Measurement} of the magnetization of thin-film samples subjected to mechanical stress},
venue = {Benevento},
year = {2014}
}
@article{faucris.217471560,
abstract = {Purpose. The treatment of skin lesions of various kinds is a common task in clinical routine. Apart from wound care, the assessment of treatment efficacy plays an important role. In this paper, we present a new approach to measure the skin lesion surface in two and three dimensions. Methods. For the 2D approach, a single photo containing a flexible paper ruler is taken. After semi-automatic segmentation of the lesion, evaluation is based on local scale estimation using the ruler. For the 3D approach, reconstruction is based on Structure from Motion. Roughly outlining the region of interest around the lesion is required for both methods. Results. The measurement evaluation was performed on 117 phantom images and five phantom videos for 2D and 3D approach, respectively. We found an absolute error of 0.99±1.18 cm2 and a relative error 9.89± 9.31% for 2D. These errors are <1 cm2 and <5% for five test phantoms in our 3D case. As expected, the error of 2D surface area measurement increased by approximately 10% for wounds on the bent surface compared to wounds on the flat surface. Using our method, the only user interaction is to roughly outline the region of interest around the lesion. Conclusions. We developed a new wound segmentation and surface area measurement technique for skin lesions even on a bent surface. The 2D technique provides the user with a fast, user-friendly segmentation and measurement tool with reasonable accuracy for home care assessment of treatment. For 3D only preliminary results could be provided. Measurements were only based on phantoms and have to be repeated with real clinical data.},
author = {Dastjerdi, Houman Mirzaalian and Toepfer, Dominique and Rupitsch, Stefan and Maier, Andreas},
doi = {10.1155/2019/4035148},
faupublication = {yes},
journal = {International Journal of Biomedical Imaging},
note = {CRIS-Team Scopus Importer:2019-05-14},
peerreviewed = {Yes},
title = {{Measuring} surface area of skin lesions with {2D} and {3D} algorithms},
volume = {2019},
year = {2019}
}
@article{faucris.107415044,
abstract = {Es wird ein Ultraschallmikroskop zur zerstörungsfreien Untersuchung gekrümmter Prüflinge vorgestellt. Kommerziell erhältliche Ultraschallmikroskope sind lediglich für die Untersuchung an ebenen Oberflächen konzipiert. Sie verfügen über ein Verfahrsystem aus zwei Linearachsen, das den Ultraschallprüfkopf während der Messung lateral über den Prüfling bewegt. Um bei Prüflingen mit gekrümmter Oberfläche eine optimale Bildqualität zu erzielen, muss der Prüfkopf so justiert werden, dass er an jedem Messpunkt orthogonal auf deren Oberfläche schallt. Im vorgestellten Messaufbau wurde dazu ein hochpräziser Roboter integriert, der über sechs Bewegungsfreiheitsgrade verfügt. Dadurch ist es möglich, neben der mäanderförmigen Abtastung durch den Ultraschallprüfkopf eine zusätzliche Winkelnachführung des Prüflings durchzuführen. In diesem Beitrag wird das entwickelte Ultraschallmikroskop in Aufbau und Funktion beschrieben. Die Auflösungsgrenzen im resultierenden Bild sowie die erreichbare Positioniergenauigkeit des Verfahrsystems werden beleuchtet. Zudem wird das Potential des Systems anhand einiger Messungen an exemplarischen Prüflingen aufgezeigt.},
author = {Wüst, Michael and Eisenhart, Johannes and Rief, Annika and Rupitsch, Stefan},
doi = {10.1515/teme-2016-0085},
faupublication = {yes},
journal = {Technisches Messen},
keywords = {Ultraschallmikroskopie; zerstörungsfreie Prüfung; Ultraschallbildgebung; gekrümmte Oberfläche},
month = {Jan},
peerreviewed = {Yes},
title = {{Messsystem} zur {Ultraschallmikroskopie} an gekrümmten {Strukturen}},
year = {2017}
}
@inproceedings{faucris.121862224,
author = {Wolf, Felix and Sutor, Alexander and Rupitsch, Stefan and Lerch, Reinhard},
booktitle = {Proceedings Sensoren und Messsysteme 2010},
faupublication = {yes},
pages = {421-424},
peerreviewed = {unknown},
title = {{Messtechnische} {Erfassung} und {Modellierung} der {Hysterese} ferroelektrischer {Werkstoffe}},
year = {2010}
}
@incollection{faucris.109894664,
abstract = {Zentrales Ergebnis des vorausgegangenen Forschungsvorhabens RENEBAT I war die Berechnung des Schlagrisikos für Fledermäuse an Windenergieanlagen (WEA) aus der automatisiert gemessenen akustischen Aktivität. Die Höhe der Fledermausaktivität (z.B. als Aufnahmen pro Stunde) hängt dabei stark von den eingesetzten Detektoren und gewählten Detektoreinstellungen ab. In RENEBAT I wurden der Batcorder (ecoObs GmbH) und der Anabat SD1 (Titley) für die Datenerfassung im Feld verwendet. In RENEBAT II wurde neben diesen Detektoren auch der Detektor UltraSoundGate (USG) der Firma Avisot Bioacoustics eingesetzt. Zunächst berechneten wir theoretisch vorhersagbare Unterschiede aus den physikalischen Eigenschaten der Detektoren, insbesondere der Mikrofone. So berechneten wir Erfassungsreichweite und -volumen anhand des Frequenzgangs und der Richtcharakteris tik der Mikrofone. Abhängig von der Frequenz des Fledermausrufs war das abgedeckte Volumen des Avisot-USGs 3 bis 3,5 mal so groß wie das des Batcorders. Bei der Triggerung (Auslösung) einer Aufnahme arbeiten das USG und der Batcorder nach einem ähnlichen Prinzip, wohingegen Titleys Anabat keine Selektion von Rufen vornimmt, sondern eine Daueraufnahme von Nulldurchgangsdaten aufzeichnet. Die theoretischen Vorhersagen wurden mit unterschiedlichen praktischen Experimenten veriiziert. Sowohl der Anabat SD1 Detektor als auch das UltraSoundGate wurden an jeweils acht Anlagen getestet, der Batcorder parallel zu jeweils einem der anderen Detektoren an 16 WEA. Durch den parallelen Einsatz war es möglich, Unterschiede in der Empindlichkeit und der daraus 6.3 Anabat System (Titley) . . . . . . . . . . . . . . . . . . . . . . . 62 7 Performance der Geräte im Vergleich . . . . . . . . . . . . . . . . . . . 63 7.1 Frequenzgang und Richtcharakteristik der Mikrofone und Mikrofonscheiben. 64 7.2 Bestimmung des Erfassungsvolumens . . . . . . . . . . . . . . . . 67 7.3 Überprüfung der theoretischen Erfassungsreichweite an einer WEA mit Hilfe einer Flugdrohne . . . . . . . . . . . . . . . . . . . . . . . . . 69 7.4 Bestimmung der Einlussfaktoren der Triggerung verschiedener akustischer Erfassungssysteme . . . . . . . . . . . . . . . . . . . . . . . . . 71 7.5 Laufzeiten und Ausfälle der Detektoren. . . . . . . . . . . . . . . . 75 7.6 Empindlichkeit für Störungen . . . . . . . . . . . . . . . . . . . 76 7.7 Aufgezeichnetes Artenspektrum . . . . . . . . . . . . . . . . . . . 78 8 Literatur. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 Einleitung 41 resultierenden Einschätzung der Aktivität für die unterschiedlichen Detektoren zu quantiizieren. In RENEBAT II wurden die Detektorsysteme im Unterschied zu RENEBAT I nicht ofen in der Gondel montiert, sondern in einem Schaltschrank aus Stahl vorinstalliert. In einem Pilotversuch wurde zudem an einzelnen Anlagen ein alternativer Aubau des UltraSoundGates von Avisot getestet, bei dem sich nur die Mikrofonscheibe in der Gondel befand und die Aufzeichnungseinheit am Anlagenfuß installiert war. Das Mikrofonsignal wurde mithilfe eines langen Kabels, das im Anlagenturm verlegt wurde, nach unten geleitet. Alle drei Detektoren erwiesen sich als geeignet für ein Gondelmonitoring zeigten jedoch deutliche Unterschiede in der Erfassungsreichweite, der Anzahl von Störungsaufnahmen, der Dauer von Ausfallzeiten und der Anzahl von Aufnahmen mit Fledermausrufen.},
address = {Hannover},
author = {Simon, Ralph and Hochradel, Klaus and Mages, Jürgen and Nagy, Martina and Naucke, Andreas and Niermann, Ivo and Weber, Natalie and Behr, Oliver},
booktitle = {Reduktion des Kollisionsrisikos von Fledermäusen an Onshore-Windenergieanlagen (RENEBAT II)},
editor = {Oliver Behr, Robert Brinkmann, Fränzi Korner-Nievergelt, Martina Nagy, Ivo Niermann, Michael Reich & Ralph Simon},
faupublication = {no},
peerreviewed = {unknown},
publisher = {Schriftenreihe Institut für Umweltplanung, Leibniz Universität Hannover},
series = {Umwelt und Raum},
title = {{Methoden} akustischer {Erfassung} der {Fledermausaktivität} an {Windenergieanlagen}},
volume = {7},
year = {2015}
}
@article{faucris.117342104,
abstract = {We present a method for optimizing the design of field coils for a new type of photobioreactor (PBR). In those PBRs, photosynthetic active microorganisms or cells are grown. A novel concept for the illumination of PBRs was necessary, as the external illumination of those reactors leads to a limited penetration depth of light. The solution we propose is an internal illumination via wireless light emitters (WLEs). This increases the manageable culture volume of photosynthetic active microorganisms or cells. The illumination system is based on floating light emitters, which are powered wirelessly by near field resonant inductive coupling. The floating light emitters are able to illuminate a PBR more homogeneously than external illumination systems. We designed field coils to produce an intermediate frequency electromagnetic field inside the reactor. We chose a magnetic flux density B = 0.95 mT and a frequency f = 178 kHz. To reach optimal efficiency, the magnetic field has to be as homogeneous as possible. We demonstrate how this optimization can be performed with the method of differential evolution. Using the optimized field coil design, the minimum magnetic field was increased by almost 10% keeping the number of ampere-turns constant. A comparison of the light profiles over the cross section of both reactor types show clearly that the internal illumination via WLE results in a more uniform light distribution and a higher average light intensity in the reactor. An impact of the magnetic field on the green alga Chlamydomonas reinhardtii could be excluded by comparing the growth rate, the achieved cell dry weight and the maximum photosynthetic yield with and without applied magnetic field. Furthermore, a negative effect of the potentially occurring mechanical stress due to the suspended WLE can be excluded. A culture which is mechanically stressed by 125 WLE per liter shows the same maximal growth rate as a control culture. Finally, the comparison of an externally and a via WLE internally illuminated PBR shows the same growth rates in the exponential growth phase. However, the growth rate in the linear phase is more than twice the rate of the externally illuminated control culture, resulting in a more than 80% higher achieved biomass.},
author = {Sutor, Alexander and Heining, Martin and Lindenberger, Christoph and Buchholz, Rainer},
doi = {10.1109/TMAG.2014.2320934},
faupublication = {yes},
journal = {IEEE Transactions on Magnetics},
keywords = {Global optimization;internal illumination;near field resonant inductive coupling;photobioreactor (PBR);wireless energy transfer;wireless light emitter (WLE)},
peerreviewed = {Yes},
title = {{Method} for {Optimizing} the {Field} {Coils} of {Internally} {Illuminated} {Photobioreactors}},
volume = {50},
year = {2014}
}
@incollection{faucris.123489784,
address = {Berlin},
author = {Behr, Oliver and Brinkmann, Robert and Hochradel, Klaus and Mages, Jürgen and Korner-Nievergelt, Fränzi and Niermann, Ivo and Reich, Michael and Simon, Ralph and Weber, Natalie and Nagy, Martina},
booktitle = {Wind Energy and Wildlife Imteractions},
doi = {10.1007/978-3-319-51272-3},
editor = {Johann Köppel},
faupublication = {yes},
isbn = {978-3-319-51272-3},
keywords = {Acoustic Activity; Bats; Collision Risk; Central Europe; Operational mitigation; Wind Turbine},
pages = {135-160},
peerreviewed = {unknown},
publisher = {Springer},
title = {{Mitigating} {Bat} {Mortality} with {Turbine}-{Specific} {Curtailment} {Algorithms}: {A} {Model} {Based} {Approach}},
year = {2017}
}
@inproceedings{faucris.223037867,
abstract = {Remote photoacoustic tomography by speckle-analysis which is based on
the measurement of the surface tilt is interesting for a lot of medical
applications such as endoscopy or wound imaging. In this work, a new
model which is capable to simulate the resulting surface tilt after
photoacoustic excitation is presented. A Monte Carlo simulation is
coupled to a stress simulation which allows the determination of the
temporal surface deformation and the resulting tilt. A first comparison
to experimental results from literature is done and discussed. In
future, this model might help to optimize the speckle-sensing technique
for photoacoustic signal detection. Furthermore, it could be used to
develop and test image reconstruction algorithm},
author = {Lengenfelder, Benjamin and Hohmann, Martin and Klämpfl, Florian and Zam, Azhar and Weiß, Manuel and Rupitsch, Stefan and Zalevsky, Zeev and Schmidt, Michael},
booktitle = {Opto-Acoustic Methods and Applications in Biophotonics IV; 110771I (2019)},
date = {2019-06-23/2019-06-27},
doi = {10.1117/12.2526593},
editor = {SPIE},
faupublication = {yes},
keywords = {Photoacoustic; remote sensing; simulation},
peerreviewed = {Yes},
title = {{Model} for the description of remote photoacoustic sensing using speckle-analysis},
venue = {Munich},
year = {2019}
}
@article{faucris.123346124,
abstract = {We present a new model for the simulation of the hysteretic large-signal behavior in ferroelectric materials. The model is based on the Preisach operator and takes advantage of an analytic weight function for the underlying fundamental switching operators. The five independent parameters describing this weight function have been determined for a discoidal piezoceramic actuator by adapting the model output to measurements of the polarization. Since the classical Preisach model is only valid for creep- and rate-independent hysteresis loops, it is inappropriate to describe the entire ferroelectric material behavior. Therefore, we extended our model by an additional drift operator to consider creep phenomena. Furthermore, the rate-dependence of the hysteresis loops is described by a frequency-dependent parameter of the analytic weight function. For the identification and verification of the model, measurements have been performed using two different measurement principles: A modified Sawyer-Tower circuit as well as a method based on the integration of the electrical current. The agreement between measurements and simulations highlights the benefits of the enhanced hysteresis model. (C) 2011 Elsevier B.V. All rights reserved.},
author = {Wolf, Felix and Sutor, Alexander and Rupitsch, Stefan and Lerch, Reinhard},
doi = {10.1016/j.sna.2011.02.026},
faupublication = {yes},
journal = {Sensors and Actuators A-Physical},
keywords = {Preisach model;Analytic weight function;Creep;Rate-dependence;Piezoceramic transducer;Polarization measurement;Piezoelectric hysteresis;Ferroelectric large-signal behavior},
pages = {245-252},
peerreviewed = {Yes},
title = {{Modeling} and measurement of creep- and rate-dependent hysteresis in ferroelectric actuators},
volume = {172},
year = {2011}
}
@inproceedings{faucris.114314244,
abstract = {We present a model for the simulation of ferroelectric hysteresis loops. It is based on the Preisach operator and takes advantage of an analytic weight function for the underlying fundamental switching operators. The five independent parameters describing this weight function are determined for a discoidal piezoceramic actuator by adapting the model output to measurements of the polarization. Further hysteresis simulations, performed using the adapted model are compared to hysteresis measurements of the actuator. To consider time dependent switching behavior of the ferroelectric domains, our model is furthermore extended by a drift operator and verified by means of additional measurements. (C) 2010 Published by Elsevier Ltd.},
author = {Wolf, Felix and Sutor, Alexander and Rupitsch, Stefan and Lerch, Reinhard},
doi = {10.1016/j.proeng.2010.09.054},
faupublication = {yes},
keywords = {Preisach model;ferroelectric behavior;piezoelectric hysteresis;drift model;piezoceramic transducer},
month = {Jan},
pages = {87-90},
peerreviewed = {unknown},
publisher = {Elsevier BV},
title = {{Modeling} and measurement of hysteresis of ferroelectric actuators considering time-dependent behavior},
volume = {5},
year = {2010}
}
@article{faucris.123027124,
abstract = {In various ferroelectric actuator applications, the active material is exposed to mechanical prestress. This is often caused by unintended clamping, such as for smart materials with embedded ferroelectric components. In other cases, the stress is applied on purpose to enhance the transducer performance or to prevent from tensile forces. Hence, the development of models, describing the transducer behavior under combined, electro-mechanical loading conditions is essential. In our previous work, we proposed an analytic weight function for the scalar Preisach hysteresis operator. The model was further enhanced to describe the dynamic material behavior of piezoceramic actuators. Here, we address the influence of uniaxial mechanical prestress on the polarization hysteresis by conducting measurements on lead zirconate titanate samples. A parameter study is performed to investigate, how the weight function can be extended to a formulation incorporating prestress. The resulting simulations coincide very well with measurements. (C) 2011 Published by Elsevier Ltd.},
author = {Wolf, Felix and Sutor, Alexander and Rupitsch, Stefan and Lerch, Reinhard},
doi = {10.1016/j.proeng.2011.12.399},
faupublication = {yes},
journal = {Procedia Engineering},
keywords = {Preisach model;analytic weight function;uniaxial compressive prestress;piezoelectric transducer;piezoceramic actuator;ferroelectric hysteresis;PZT},
month = {Jan},
pages = {1613-1616},
peerreviewed = {unknown},
title = {{Modeling} and measurement of influence of mechanical prestress on hysteresis of ferroelectric actuators},
volume = {25},
year = {2011}
}
@article{faucris.249966832,
abstract = {We present an overview of different modeling strategies for piezoelectric vibration energy harvesters. We point out different strength and weaknesses of common models for the electromechanical structure. Furthermore, simulation approaches for a combined simulation of the piezoelectric structure and energy extraction networks (EENs) are discussed and their basic implementations are described. We present an example of such an EEN that is controlled by the voltage of a separate electrode on the harvesting structure. Advantages of this technique over uncontrolled approaches are discussed.},
author = {Gedeon, Dominik and Dorsch, Philipp and Rupitsch, Stefan Johann},
doi = {10.1109/JSEN.2021.3053338},
faupublication = {yes},
journal = {IEEE Sensors Journal},
keywords = {Couplings; Electrodes; Energy Harvesting; Finite Element Method; Integrated circuit modeling; Iron; Mathematical model; Modeling; Numerical models; Piezoelectricity; Power Electronics; Simulation; Vibrations},
note = {CRIS-Team Scopus Importer:2021-02-19},
peerreviewed = {Yes},
title = {{Modeling} and {Simulation} {Approaches} for {Piezoelectric} {Vibration} {Energy} {Harvesting} {Systems}},
year = {2021}
}
@inproceedings{faucris.284510857,
abstract = {This interdisciplinary workshop aims to break boundaries between the researchers who develop human models (e.g., from the fields of human factors, cognitive psychology, and computational neuroscience) and roboticists who use human models in different human-robot interaction (HRI) contexts. The keynote talks, contributed submissions, and interactive discussions will focus on the questions such as: How can modeling humans help us understand and design human-robot interactions? What kinds of models are useful for which HRI contexts (physical/cognitive interactions) and purposes (behavior prediction/personalization/theory -of- mind/etc.)? What common lessons can be learned from human behavior modeling in HRI across different application domains? How can modeling humans in HRI tasks help us to better understand human cognition/behavior? By stimulating an interdisciplinary conver-sation around these questions, we aim to raise awareness of the benefits of modeling and expose the wider HRI community to a variety of different modeling approaches, and facilitate the HRI researchers who already engage in modeling to exchange views on methodology of modeling and best nractices from diverse fields.},
author = {Zgonnikov, Arkady and Thill, Serge and Beckerle, Philipp and Jonker, Catholijn M.},
booktitle = {ACM/IEEE International Conference on Human-Robot Interaction},
date = {2022-03-07/2022-03-10},
doi = {10.1109/HRI53351.2022.9889403},
faupublication = {yes},
isbn = {9781538685549},
keywords = {human behavior; Human-robot interaction; modeling},
note = {CRIS-Team Scopus Importer:2022-11-04},
pages = {1296-1297},
peerreviewed = {unknown},
publisher = {IEEE Computer Society},
title = {{Modeling} {Human} {Behavior} in {Human}-{Robot} {Interactions}},
venue = {Sapporo, JPN},
volume = {2022-March},
year = {2022}
}
@inproceedings{faucris.123244484,
abstract = {Die Ultraschallmikroskopie ist ein gebräuchliches Verfahren für die zerstörungsfreie Werkstoffprüfung. Sie findet beispielsweise in der Halbleitertechnologie zur Visualisierung von Fehlstellen Anwendung. Konventionelle Ultraschallmikroskope verfügen aufgrund der erforderlichen hohen Schallfrequenzen (10 bis einige 100 MHz) lediglich über einen Einzelwandler-Prüfkopf mit fokussierender Linse, der mechanisch über den zu untersuchenden Prüfling geführt wird. Der Betrieb erfolgt üblicherweise im Puls-Echo-Modus.
Die emittierte Schallkeule wird durch eine sphärisch fokussierende Linse auf ein Fokusgebiet gebündelt. In diesem Tiefenbereich kann somit ein Bild mit einem hohen lateralen Ortsauflösungsvermögen gewonnen werden. Aufgrund der mit dem Abstand zum Fokus zunehmenden lateralen Breite des Schallfeldes wird ein punktförmiger Reflektor von mehreren Messpositionen aus detektiert. Außerhalb des Fokusgebietes ergeben sich je nach Messposition verschiedene Laufzeitunterschiede zwischen der Position der Prüfkopf-Oberfläche und dem Reflektorpunkt. In der Folge werden solche Targets als eine hyperbelförmige Sichel abgebildet. Da die Information über die tatsächliche Reflektivitätsverteilung im untersuchten Messgebiet aber prinzipiell in den erfassten Zeitrohdaten enthalten ist, kann diese durch synthetische Aperturfokussierungstechniken (SAFT) rekonstruiert werden.
Ein gängiges SAFT-Verfahren ist die Fokussierung mit dem Delay-and-Sum-Algorithmus (DAS). DAS führt für jeden Bildpunkt eine Laufzeitkorrektur der Signale unterschiedlicher Messpositionen durch und summiert die korrigierten A-Linien kohärent auf. Dazu wird die Schallkeule rein strahlenakustisch betrachtet und für die Laufzeitverschiebung der Fokus als punktförmige Quelle interpretiert. Dieses Verfahren ist auch als Prinzip der virtuellen Quelle bekannt und sowohl für Fluide als auch für Festkörper anwendbar.
Das hier vorgestellte Fokussierungsverfahren verfolgt einen modellbasierten Ansatz. Dieser basiert auf einem semi-numerischen Simulationsmodell der Messkette vom Aussenden des Schallpulses bis zum Empfang der Echosignale. Dabei wird die Schallausbreitung im Koppelmedium (Wasser) zwischen dem Prüfkopf und der Probe analytisch berechnet und ggf. die Schallausbreitung in einem angrenzenden Festkörper numerisch simuliert. Somit ist der präzise räumliche und zeitliche Verlauf des emittierten Schallpulses bestimmbar. Aus der genauen Kenntnis der Schallausbreitung während der Messung kann ein angepasster Filterkern generiert werden, welcher der Punkt-Bild-Funktion des Messsystems entspricht.
Das Potenzial der modellbasierten SAFT wird anhand verschiedener Reflektoren sowohl in Wasser als auch in Festkörperproben demonstriert und den Ergebnissen der DAS-basierten SAFT gegenüber gestellt. Es lässt sich zeigen, dass sowohl das laterale als auch das axiale Ortsauflösungsvermögen signifikant gesteigert werden können.}, author = {Wüst, Michael and Schwarz, Michael and Eisenhart, Johannes}, booktitle = {Schallfeldbasierte Messverfahren - vom Transducer bis zur praktischen Anwendung}, date = {2017-07-10/2017-07-12}, faupublication = {yes}, keywords = {Ultraschallmikroskopie; zerstörungsfreie Prüfung; Synthetische Aperturfokussierungstechnik}, pages = {26}, peerreviewed = {No}, title = {{Modellbasierte} {Fokussierungstechnik} mit synthetischer {Apertur} zur {Ultraschallmikroskopie} für fluide {Medien} und {Festkörper}}, venue = {Drübeck}, year = {2017} } @inproceedings{faucris.107037744, abstract = {
Synthetische Aperturfokussierungstechniken (SAFT) werden bei ultraschallbasierten bildgebenden Messverfahren zur Verbesserung der Ortsauflösung im Bild eingesetzt. Zumeist berücksichtigen übliche SAFT-Algorithmen aber nicht den inneren Aufbau des untersuchten Prüflings. Im Folgenden wird ein Verfahren zur Ultraschallmikroskopie vorgestellt, das einen angepassten SAFT-Algorithmus zur Bildrekonstruktion nutzt. Das Verfahren wird zur zerstörungsfreien Werkstoffprüfung herangezogen. Es dient der Detektion und dimensionellen Erfassung von Fehlstellen innerhalb des Prüflings (z. B. Delaminationen in heterogenen Werkstoffverbunden). Dabei ist die Soll-Geometrie des untersuchten Prüflings a priori bekannt. Unter Nutzung dieser Vorkenntnisse können die Messsignale simuliert werden, die bei einer fehlerfreien Geometrie resultieren würden. Aus den erzeugten Daten wird ein räumlicher Filterkern modelliert, der die Grundlage des SAFT- Algorithmus bildet. Die Simulation mittels Finiter-Elemente- Methode (FEM) ist allerdings außerordentlich rechenintensiv und daher nicht praktikabel. Eine Reduzierung des Aufwands kann aber erreicht werden, indem eine analytische Berechnung des transienten Schallfeldes im Koppelmedium (Wasser) zwischen Ultraschall-Prüfkopf und Prüfling erfolgt. Hierfür kann die sogenannte ortsabhängige Impulsantwort (engl. ”Spatial Impulse Response”, kurz SIR) herangezogen werden. Für die Simulation der Schallausbreitung im Prüfling wird die FEM mit Ansatzfunktionen höherer Ordnung implementiert. Dieses hybride Simulationsverfahren wird als ”SIRFEM” bezeichnet. Das dadurch verbesserte Ortsauflösungsvermögen wird anhand erster Ergebnisse am Beispiel geometrisch simpler Prüflinge aufgezeigt.
}, author = {Wüst, Michael and Nierla, Michael and Rupitsch, Stefan}, booktitle = {Fortschritte der Akustik}, date = {2015-03-16/2015-03-19}, editor = {Deutsche Gesellschaft für Akustik e. V. (DEGA)}, faupublication = {yes}, isbn = {978-3-939296-08-9}, keywords = {Ultraschall; Mikroskopie; zerstörungsfreie Prüfung}, pages = {1566-1569}, peerreviewed = {unknown}, title = {{Modellgestützte} {Ultraschallmikroskopie} zur dimensionellen {Erfassung} von {Fehlstellen} in {Festkörpern}}, venue = {Nürnberg}, year = {2015} } @inproceedings{faucris.114315124, abstract = {A model aimed to describe the capacitance between probe electrodes and the conductive parts of planar electronic devices is presented. The probe electrodes are the constitutive part of a sensor chip used in an inspection system which is exclusively based on capacitive coupling and employed for the inspection of devices such as flat panel displays and printed electronic circuits. Finite element (FE) simulations of the sensor signal are used to determine the model parameters and to verify the obtained results. The capacitive coupling for arbitrary configurations of parallel arranged conductor tracks and various distances between the tracks and the sensor chip is reproduced by the model. Absolute values of the capacitance with deviations below 5% can be obtained. (C) 2010 Published by Elsevier Ltd.}, author = {Koerdel, M. and Alatas, F. and Schick, A. and Rupitsch, Stefan and Lerch, Reinhard}, doi = {10.1016/j.proeng.2010.09.131}, faupublication = {yes}, keywords = {flat panel display (FPD);planar electronic device;contactless inspection system;capacitive coupling;finite element (FE) simulation;nonmatching grids}, month = {Jan}, pages = {400-403}, peerreviewed = {unknown}, publisher = {Elsevier BV}, title = {{Modelling} the capacitive coupling of sensors applied to the contactless inspection of planar electronics}, volume = {5}, year = {2010} } @article{faucris.206146783, author = {Zhou, Juncen and Fink, Michael and Bruns, Mark and Yang, Yuyun and Detsch, Rainer and Boccaccini, Aldo R. and Ermert, Helmut and Virtanen, Sannakaisa}, doi = {10.1016/j.msec.2018.10.079}, faupublication = {yes}, journal = {Materials Science and Engineering C}, peerreviewed = {Yes}, title = {{Modification} of in vitro degradation behavior of pure iron with ultrasonication treatment: {Comparison} of two different pseudo-physiological solutions}, year = {2018} } @article{faucris.217940857, abstract = {We present an enhanced version of our previously engineered MyoRobot system for reliable, versatile and automated investigations of skeletal muscle or linear polymer material (bio)mechanics. That previous version already replaced strenuous manual protocols to characterize muscle biomechanics properties and offered automated data analysis. Here, the system was further improved for precise control over experimental temperature and muscle single fiber sarcomere length. Moreover, it also now features the calculation of fiber cross-sectional area via on-the-fly optical diameter measurements using custom-engineered microscope optics. With this optical systems integration, the MyoRobot 2.0 allows to tailor a wealth of recordings for relevant physiological parameters to be sequentially executed in living single myofibers. Research questions include assessing temperature-dependent performance of active or passive biomechanics, or automated control over length-tension or length-velocity relations. The automatically obtained passive stress-strain relationships and elasticity modules are important parameters in (bio)material science. From the plethora of possible applications, we validated the improved MyoRobot 2.0 by assessing temperature-dependent myofibrillar Ca 2+ sensitivity, passive axial compliance and Young's modulus. We report a Ca 2+ desensitization and a narrowed dynamic range at higher temperatures in murine M. extensor digitorum longus single fibers. In addition, an increased axial mechanical compliance in single muscle fibers with Young's moduli between 40 - 60 kPa was found, compatible with reported physiological ranges. These applications demonstrate the robustness of our MyoRobot 2.0 for facilitated single muscle fiber biomechanics assessment.}, author = {Haug, Michael and Meyer, Charlotte and Reischl, Barbara and Prölß, Gerhard and Nübler, Stefanie and Schürmann, Sebastian and Schneidereit, Dominik and Heckel, Michael and Pöschel, Thorsten and Rupitsch, Stefan and Friedrich, Oliver}, doi = {10.1016/j.bios.2019.04.052}, faupublication = {yes}, journal = {Biosensors and Bioelectronics}, keywords = {Axial compliance; Biomechatronics; Biosensor; Ca2+ sensitivity; EDL; MyoRobot; Sarcomere length; Single fiber; Skeletal muscle; Temperature control; Young's modulus}, note = {CRIS-Team Scopus Importer:2019-05-21}, peerreviewed = {Yes}, title = {{MyoRobot} 2.0: {An} advanced biomechatronics platform for automated, environmentally controlled skeletal muscle single fiber biomechanics assessment employing inbuilt real-time optical imaging}, volume = {138}, year = {2019} } @inproceedings{faucris.106635144, abstract = {Many piezoelectric sensor concepts, such as quartz crystal microbalances or piezoelectric temperature sensors, exploit the frequency shift of their resonance frequency as an electric output signal. The resonance frequency of the sensor has to be converted into a frequency-proportional output signal by a subsequent oscillator circuit. Therefore, reliable sensor data processing requires a matching of the resonance frequency and the oscillator frequency at any ambient condition. This contribution focuses on the design of low-cost oscillators with a piezoelectric sensor as the frequency-determining component. Different oscillator topologies will be analyzed regarding their suitability for measurement data processing. In order to achieve a simple and efficient circuit layout, we developed a hybrid design concept based on analytical models and circuit simulations. Experimental results, based on a piezoelectric temperature sensor, prove the proposed design concepts. In the temperature range from -20 °C to 85 °C, an extremely small deviation of less than 0.2 % between the resonance frequency and the oscillator frequency was obtained.
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Either the thickness of a plate or its speed of sound can be determined by ultrasonic time-of-flight measurement if the other parameter is given. Often, however, both quantities are unknown. In this case, reverberation in the plate can be harnessed to determine both parameters simultaneously, which is specially valuable for non-destructive testing applications. To characterize thinner plates, it is necessary to increase the axial resolution of the measurement system. This is accomplished by conditioning the signal that drives the ultrasonic transducer. A new approach for signal conditioning is presented and applied to a linear frequency modulated signal, which represents a coded excitation signal and, therefore, provides improved signal-to-noise ratio compared to pulsed operation. However, due to the inherently long duration of coded excitation signals, pulse compression is needed to perform time-of-flight measurements. Well known pulse compression techniques are compared experimentally with regard to achievable axial resolution and side lobe level. Plates of steel, aluminum and polymethylmethacrylate (PMMA, acrylic glass) are characterized with the presented technique. The measurement results for plate thickness and speed of sound show very good agreement with the reference values.}, address = {Aachen}, author = {Kiefer, Daniel A. and Fink, Michael and Rupitsch, Stefan}, booktitle = {5. Tagung Innovation Messtechnik}, date = {2017-05-11/2017-05-11}, editor = {Bernhard G. Zagar}, faupublication = {yes}, isbn = {978-3-8440-5163-6}, keywords = {Ultraschall; codierte Ansteuersignale; Pulskompression; Messtechnik; Dicke; Schallgeschwindigkeit; Platten; Chirps}, pages = {71 - 75}, peerreviewed = {Yes}, publisher = {Shaker Verlag GmbH}, title = {{Simultane} {Bestimmung} der {Plattendicke} und {Schallgeschwindigkeit} mit codierten {Ultraschallsignalen}}, venue = {Haus der Ingenieure, Wien}, year = {2017} } @inproceedings{faucris.124034724, author = {Rupitsch, Stefan and Fink, Michael and Lerch, Reinhard}, booktitle = {Fortschritte der Akustik - DAGA 2014}, date = {2014-03-10/2014-03-13}, faupublication = {yes}, pages = {545 - 546}, peerreviewed = {unknown}, title = {{Simultane} {Ermittlung} von {Schallgeschwindigkeit} und {Dicke} dünner {Platten} mittels {Ultraschall}}, venue = {Oldenburg}, year = {2014} } @inproceedings{faucris.114330304, abstract = {We propose an approach to simultaneously identify the speed of sound (SOS) in a flat homogeneous material specimen and its thickness by means of ultrasound. Basically, the setup operating in transmission mode consists of an ultrasound transducer and an opposed hydrophone. In contrast to common approaches, where short broadband pulses are utilized, the ultrasound transducer is here excited with a continuous sinusoidal signal being phase-modulated. The phase modulation is carried out with a Gold sequence offering outstanding correlation properties. In order to determine SOS and sample thickness, the time-of-flight (TOF) for sound waves propagating directly from transducer to hydrophone as well as for those being multiple reflected within the specimen is analyzed. For this purpose, we perform two subsequent signal processing steps: (i) signal correlation, and (ii) numerical search for multiple reflections. As the results for different solid material specimen reveal, the approach yields precise values for both, SOS and sample thickness.}, author = {Rupitsch, Stefan and Glaser, Daniel and Lerch, Reinhard}, doi = {10.1109/ULTSYM.2012.0177}, faupublication = {yes}, month = {Jan}, pages = {711-714}, peerreviewed = {unknown}, publisher = {IEEE SERVICE CENTER, 445 HOES LANE, PO BOX 1331, PISCATAWAY, NJ 08855-1331 USA}, title = {{Simultaneous} {Determination} of {Speed} of {Sound} and {Sample} {Thickness} {Utilizing} {Coded} {Excitation}}, year = {2012} } @article{faucris.123772484, abstract = {Layer thickness and speed of sound are important parameters for non-destructive testing applications. If one of the parameters is known, the other one can be determined by simple time-of-flight measurement of ultrasound. However, often these parameters are both unknown. In this contribution, we examine and adapt ultrasonic imaging techniques using coded excitation signals to simultaneously measure the thickness and speed of sound in homogeneous elastic plates of unknown material. Good axial resolution is required to measure thin samples. We present a new approach for transmission signal conditioning to improve axial resolution. This conditioning consists of enhancing spectral components which are damped by the transducer prior to transmit. Due to the long duration of coded excitation signals, pulse compression techniques are required for time-of-flight measurements. Common pulse compression filters are discussed and appropriate filtering of the compression waveform is designed to keep the side lobe level acceptably low. An experimental assessment of the presented measurement techniques reveals that the signal conditioning substantially increases the axial resolution. However, a tapered Wiener filter should be used for best trade-off between side lobe level and axial resolution. We used the proposed method to measure different plates of steel, aluminum and polymethylmethacrylate (PMMA) of various thicknesses and the results show very good agreement with the reference values, which we obtained with a micrometer screw and by standard time-of-flight measurement, respectively. The relative error for the plate thickness is smaller than 2.2% and that for speed of sound smaller than 3%. It is remarkable that plate thickness could be measured down to 60% of the wavelength.}, author = {Kiefer, Daniel A. and Fink, Michael and Rupitsch, Stefan}, doi = {10.1109/TUFFC.2017.2746900}, faupublication = {yes}, journal = {IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control}, keywords = {ultrasound; pulse compression; axial resolution; simultaneous; thickness; speed of sound; plate; measurement}, peerreviewed = {Yes}, title = {{Simultaneous} {Ultrasonic} {Measurement} of {Thickness} and {Speed} of {Sound} in {Elastic} {Plates} using {Coded} {Excitation} {Signals}}, volume = {99}, year = {2017} } @inproceedings{faucris.123031084, abstract = {The integration of piezoceramic based sensors and actuators offers a possibility to produce multifunctional materials with enhanced properties. Die casting is an innovative approach for the fabrication of metal matrix smart structural components where the functional module is totally integrated in the interior of the cast part. A technique to support and protect the sensitive sensor/actuator-modules in the die during the highly dynamic die filling process is presented. Demonstration parts were produced which are fully capable to be activated to vibrate. An approach to characterize in detail the behavior of the sensor/actuator-module after the integration in the cast matrix is presented. Both FE computation and electric impedance measurements are used to quantify how the casting process affects the performance of the integrated sensor/actuator-modules.}, author = {Bräutigam, Volker and Körner, Carolin and Singer, Robert and Kaltenbacher, Manfred and Meiler, Martin and Lerch, Reinhard}, booktitle = {Industrial and Commercial Applications of Smart Structures Technologies 2007}, doi = {10.1117/12.705831}, faupublication = {yes}, isbn = {9780819466488}, keywords = {Characterization; Die casting; Electric impedance; Finite element calculations; Integration; Piezoceramic module; Smart structure}, peerreviewed = {unknown}, title = {{Smart} structural components by integration of sensor/actuator-modules in die castings}, venue = {San Diego, CA}, volume = {6527}, year = {2007} } @inproceedings{faucris.206144443, author = {Fink, Michael and Lyer, Stefan and Alexiou, Christoph and Ermert, Helmut}, booktitle = {Current Directions in Biomedical Engineering}, date = {2018-09-26/2018-09-28}, doi = {10.1515/cdbme-2018-0109}, editor = {De Gruyter}, faupublication = {yes}, pages = {457 - 459}, peerreviewed = {Yes}, title = {{Sonographic} {Detection} of {Iron} {Oxide} {Nanoparticles} {Employing} {Shear} {Waves}}, venue = {Aachen}, year = {2018} } @inproceedings{faucris.117661984, author = {Fink, Michael and Nüsslein, Moritz and Ermert, Helmut and Lyer, Stefan and Alexiou, Christoph}, booktitle = {Proceedings IEEE IUS 2015}, date = {2015-10-21/2015-10-24}, doi = {10.1109/ULTSYM.2015.0263}, faupublication = {yes}, pages = {1-6}, peerreviewed = {unknown}, title = {{Sonographic} detection of magnetic nanoparticles for {Magnetic} {Drug} {Targeting} in weak echogenic tissue}, venue = {Taipei}, year = {2015} } @inproceedings{faucris.118066784, author = {Fink, Michael and Ermert, Helmut and Lyer, Stefan and Alexiou, Christoph}, booktitle = {Proceedings IEEE IUS 2016}, date = {2016-09-18/2016-09-21}, doi = {10.1109/ULTSYM.2016.7728404}, faupublication = {yes}, pages = {1-6}, peerreviewed = {unknown}, title = {{Sonographic} {Detection} of {Magnetic} {Nanoparticles} for {Magnetic} {Drug} {Targeting} {Using} {Coded} {Magnetic} {Fields}}, venue = {Tours}, year = {2016} } @inproceedings{faucris.109634624, author = {Fink, Michael and Ermert, Helmut and Löffler, Michael and Sutor, Alexander and Tewes, Barbara and Koch, Andreas and Alexiou, Christoph and Lyer, Stefan}, booktitle = {Proceedings SENSOR 2015}, date = {2015-05-19/2015-05-21}, doi = {10.5162/sensor2015/C5.3}, faupublication = {yes}, isbn = {978-3-9813484-8-4}, pages = {430 - 435}, peerreviewed = {unknown}, title = {{Sonographic} {Detection} of {Nanoparticles} used for {Magnetic} {Drug} {Targeting}}, venue = {Nürnberg}, year = {2015} } @inproceedings{faucris.122498904, address = {Atlanta, GA, USA}, author = {Albach, Thorsten and Horn, Peter and Sutor, Alexander and Lerch, Reinhard}, booktitle = {55th Annual Conference on Magnetism and Magnetic Materials (MMM)}, faupublication = {yes}, peerreviewed = {No}, publisher = {PCI/AIP and IEEE}, title = {{Sound} {Generation} {Using} a {Magnetostrictive} {Micro}-{Actuator}}, year = {2010} } @article{faucris.124127564, abstract = {In this paper, we present the design and performance of a MEMS-device based on the magnetostrictive effect, which can be used as a micro-loudspeaker. The device basically consists of a comb structure of monomorph bending cantilevers with an active area up to 3.0 x 2.5 mm(2). It produces a sound-pressure-level up to 101 dB at 400 Hz in a standard 2 ccm measurement volume. We show our measurement setup as well as a mechanic-acoustic-coupled lumped element model to calculate sound pressure. The model incorporates finite element results for mechanical behavior. Measurement results validate our model assumptions. (C) 2011 American Institute of Physics. [doi:10.1063/1.3554200]}, author = {Albach, Thorsten and Horn, Peter and Sutor, Alexander and Lerch, Reinhard}, doi = {10.1063/1.3554200}, faupublication = {yes}, journal = {Journal of Applied Physics}, peerreviewed = {Yes}, title = {{Sound} {Generation} {Using} a {Magnetostrictive} {Microactuator}}, volume = {109}, year = {2011} } @article{faucris.123704504, abstract = {
}, author = {Nierla, Michael and Sutor, Alexander and Rupitsch, Stefan and Kaltenbacher, Manfred}, doi = {10.1108/COMPEL-02-2017-0073}, faupublication = {yes}, journal = {Compel-The International Journal For Computation and Mathematics in Electrical and Electronic Engineering}, keywords = {Everett function, Vector hysteresis, Vector Preisach model}, pages = {1501-1516}, peerreviewed = {Yes}, title = {{Stageless} evaluation for a vector {Preisach} model based on rotational operators}, volume = {36}, year = {2017} } @inproceedings{faucris.106544504, abstract = {
Die Ultraschallmikroskopie ist ein etabliertes Messprinzip der bildgebenden zerstörungsfreien Werkstoffprüfung. Sie findet dort Anwendung, wo das Auftreten von Materialinhomogenitäten (z.B. Risse und Delaminationen) zu Einschränkungen der Funktionalität des zu prüfenden Bauteils führen kann. Konventionelle Ultraschallmikroskope arbeiten mit einem hochfrequenten Einzelwandler-Prüfkopf, der meanderförmig mittels zweier Linearachsen entlang der Oberfläche des Prüflings verfahren wird. An gekrümmten Bauteilen können dabei lediglich an den Positionen reflektierte Echos empfangen werden, an denen die Schallkeule nahezu orthogonal auf die Oberfläche des Prüflings trifft. Ist dies nicht der Fall, laufen die reflektierten Echos aufgrund der Brechungen an Materialgrenzschichten nicht zum Prüfkopf zurück. Es kommt folglich zu Abschattungen im Bild. Daher ist es erforderlich, den Prüfling entsprechend so nachzuführen, dass der auftreffende Schall möglichst orthogonal einfällt. Zur präzisen Winkelnachführung wird dem konventionellen Aufbau ein Hexapod-Robotersystem hinzugefügt. Dieses bietet den Vorteil außerordentlich hoher Positioniergenauigkeiten, weist aber einen für seine Abmessungen vergleichsweise kleinen möglichen Bewegungsraum auf, weswegen die beiden Linearachsen in der Lateralebene weiterhin erforderlich sind. Um die Kontur des Prüflings zu ermitteln, wird vorab eine Kalibrierung des gesamten Verfahrsystems durchgeführt. Dadurch sind die Messpositionen und die dafür erforderlichen Stellwinkel bekannt. In diesem Beitrag werden das Kalibrierverfahren sowie Aufbau und Funktion des Messsystems vorgestellt.
}, author = {Wüst, Michael and Eisenhart, Johannes and Rief, Annika and Rupitsch, Stefan}, booktitle = {Fortschritte in der Akustik - DAGA 2017}, date = {2017-03-06/2017-03-09}, faupublication = {yes}, isbn = {978-3-939296-12-6}, pages = {991 - 994}, peerreviewed = {unknown}, title = {{Ultraschallmikroskop} zur zerstörungsfreien {Untersuchung} an gekrümmten {Bauteilen}}, venue = {Kiel}, year = {2017} } @inproceedings{faucris.289690826, address = {NEW YORK}, author = {Ben Dali, Omar and Sellami, Youssef and Zhukov, Sergey and Von Seggern, Heinz and Schaefer, Niklas and Latsch, Bastian and Sessler, Gerhard M. and Beckerle, Philipp and Kupnik, Mario}, booktitle = {2022 IEEE SENSORS}, doi = {10.1109/SENSORS52175.2022.9967198}, faupublication = {yes}, month = {Jan}, note = {CRIS-Team WoS Importer:2023-02-24}, peerreviewed = {unknown}, publisher = {IEEE}, title = {{Ultrasensitive} and low-cost insole for gait analysis using piezoelectrets}, venue = {Dallas, TX}, year = {2022} } @article{faucris.111454244, author = {Fendt, Karl and Mooshofer, Hubert and Rupitsch, Stefan and Ermert, Helmut}, faupublication = {yes}, journal = {IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control}, pages = {874-885}, peerreviewed = {unknown}, title = {{Ultrasonic} {Defect} {Characterization} in {Heavy} {Rotor} {Forgings} by {Means} of the {Synthetic} {Aperture} {Focusing} {Technique} and {Optimization} {Methods}}, year = {2016} } @inproceedings{faucris.114006684, abstract = {This paper describes an improved synthetic-aperture-focusing-technique (SAFT) for ultrasonic defect detection in multi-material devices with a circular cylindrical geometry. In conventional SAFT, defect imaging resolution in such specimen is limited, due to refraction at material interfaces. Hence, the improved technique allows to increase the probability of detection (POD) and the resolution of defects in multi-material, axis-symmetric devices. Especially, if defects are located in layers far away from the device surface and the discrepancies in the speed of sound (SOS) of the specimen materials are thoroughly substantial, it is indispensable to implicate refraction effects in the SAFT processing. Thereby, the examination is divided into three major steps. First, a specimen is scanned by rotating a spherically focused immersion ultrasound transducer around it. In a second step, a corrected time of flight (TOF) distribution is calculated by a fast marching method (FMM) with the à-priori knowledge of the specimen layout and the different SOS in the materials. As third and last step, the improved SAFT is performed utilizing the TOF distribution. To verify improvements in comparison to a conventional SAFT, a specimen is inspected, consisting of a steel and a polyvinyl chloride (PVC) part. © 2012 IEEE.}, author = {Scharrer, Thomas and Koch, Andreas and Fendt, Karl and Rupitsch, Stefan and Sutor, Alexander and Ermert, Helmut and Lerch, Reinhard}, booktitle = {2012 IEEE International Ultrasonics Symposium Proceedings}, date = {2012-10-07/2012-10-10}, doi = {10.1109/ULTSYM.2012.0260}, faupublication = {yes}, isbn = {9781467345613}, pages = {1039-1042}, peerreviewed = {No}, title = {{Ultrasonic} defect detection in multi-material, axis-symmetric devices with an improved synthetic aperture focusing technique ({SAFT})}, venue = {Dresden}, year = {2012} } @inproceedings{faucris.114008664, abstract = {In this contribution, we present a method to complement missing X-ray computed tomography (CT) data of irregular shaped metallic specimen, like turbine blades, by ultrasonic testing in immersion mode. Therefore, an adapted 360° synthetic-aperture-focusing-technique (SAFT) is used to obtain particular information of the inner pattern of the specimen. These structural information cannot be imaged by X-ray CT due to limited penetration in specific directions and consequently absent projections in the dataset. However, arising artifacts caused by refraction and signal reverberation impede the detection of the desired structural information by ultrasonic testing of those irregular metallic specimens. To cope with refraction effects caused by the immense discrepancies in speed of sound (SOS) at the interface of the couplant and the specimen, the approach is based on virtual source elements. Furthermore, the covering of near-surface structures by the first reflection signals is treated by a subspace based filtering approach and signal reverberation artifacts are suppressed by predictive deconvolution. © 2013 IEEE.}, author = {Scharrer, Thomas and Koch, Andreas and Rupitsch, Stefan and Sutor, Alexander and Ermert, Helmut and Lerch, Reinhard}, booktitle = {2013 IEEE International Ultrasonics Symposium Proceedings}, date = {2013-07-21/2013-07-25}, doi = {10.1109/ULTSYM.2013.0039}, faupublication = {yes}, isbn = {9781467356862}, month = {Jan}, pages = {150-153}, peerreviewed = {No}, title = {{Ultrasonic} imaging of a turbine blade model using a 360° synthetic-aperture-focusing-technique and reverberation suppression}, venue = {Prague}, year = {2013} } @article{faucris.114008884, abstract = {In the evaluation of large-scale metallic specimens, X-ray CT suffers from limited penetration, which results in artifacts in the reconstructed image. Data fusion of information obtained by different modalities allows correction of those artifacts. In this contribution, an approach is presented to provide complementary data of the inner pattern of the specimen by ultrasonic testing in immersion mode. To process an ultrasonic imaging full-angle synthetic aperture focusing technique, data are acquired along the a priori known contour of the specimen. Substantial discrepancies in speed of sound between the couplant and the material of the specimen lead to refraction effects which are corrected by a virtual source element method. Furthermore, several incident angles at each virtual source are utilized to achieve an enhanced detectability of inner structural edges. However, arising reverberations limit image quality and must be suppressed by predictive deconvolution. Additionally, a subspace analysis and projection method is utilized to remove echoes of the a priori known surface in the reconstructed image which potentially mask information of near-surface structures. In comparison with exclusively perpendicular insonification, resulting images show a significant enhanced possibility of detection for inner structural edges even in adverse orientations for ultrasonic imaging. Furthermore, surface echoes and reverberations are suppressed by the proposed filter methods in a reliable way.}, author = {Scharrer, Thomas and Schrapp, Michael and Rupitsch, Stefan and Sutor, Alexander and Lerch, Reinhard}, doi = {10.1109/TUFFC.2014.2974}, faupublication = {yes}, journal = {IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control}, pages = {830-839}, peerreviewed = {Yes}, title = {{Ultrasonic} imaging of complex specimens by processing multiple incident angles in full-angle synthetic aperture focusing technique}, volume = {61}, year = {2014} } @article{faucris.121556864, abstract = {Ferroelectret materials can be utilized to set up electroacoustic transducers. The materials offer both, a rather large bandwidth and a high piezoelectric strain constant. Due to its cellular structure, the material is flexible and exhibits an excellent matching to air. Therefore, this polymer is appropriate for many sound as well as ultrasound transducer applications. Our research is concentrated on the simulation based design and characterization of ultrasound transducers. In this contribution, we present a finite element based modeling of the cellular structured ferroelectret materials. In particular, a microscopic as well as a macroscopic model is discussed. We fabricate single element and array transducers based on ferroelectret materials, namely the so-called EMFi (Electro-Mechanical-Film) material. To show the applicability of ferroelectret materials for ultrasound transducers, different applications in air and water are presented. An emitter-receiver-unit is introduced which is utilized in an artificial bat head and allows the functional reproduction of the biosonar system found in bats. Moreover, a robust sensor array consisting of 16 single elements (4x4) is studied. With the aid of this sensor array, cavitation effects in ultrasonic cleaning systems can be investigated on the specimen's surface, which is not possible with common ultrasound sensors, e.g., hydrophones.}, author = {Rupitsch, Stefan and Lerch, Reinhard and Strobel, Jens and Streicher, Alexander}, faupublication = {yes}, journal = {IEEE Transactions on Dielectrics and Electrical Insulation}, keywords = {Ferroelectret material;ultrasound transducer;sensor array;numerical simulation;artificial bat head;ultrasonic cleaning;cavitation;spatially resolved cavitation sensor;EMFi;material characterization}, pages = {69-80}, peerreviewed = {Yes}, title = {{Ultrasound} {Transducers} {Based} on {Ferroelectret} {Materials}}, volume = {18}, year = {2011} } @article{faucris.110529584, abstract = {Ein Amplified Piezo Actuator besteht aus einem piezoelektrischen Stapelaktor und einem metallischen Festkörpergelenkrahmen. Durch diese Kombination ist trotz geringer mechanischer Auslenkungen des Stapelaktors ein für viele Anwendungen nötiger, größerer Stellweg realisierbar. Gleichzeitig können die Vorteile des piezoelektrischen Wandlerprinzips wie hohe Präzision, hohe Eigenfrequenz und hohe Blockierkraft beibehalten werden. Für den Entwurf eines solchen Amplified Piezo Actuators können sowohl analytische Modelle als auch numerische Simulationen hinzugezogen werden. In dieser Arbeit werden ausgewählte analytische Modelle hergeleitet und hinsichtlich eines konkreten Anwendungsbeispiels angepasst. Dies beinhaltet eine rein geometrische Betrachtung, die Beschreibung des mechanischen Aktorverhaltens durch ein elastostatisches sowie ein nachgiebigkeitsbasiertes Modell. Zudem werden Parameterstudien mithilfe entsprechender numerischer Simulationen durchgeführt. Die aus den Simulationsergebnissen gezogenen Schlüsse fließen in die Fertigung von fünf Festkörpergelenkrahmen mit unterschiedlichen Eigenschaften ein. Die Validierung der analytischen und numerischen Modelle anhand durchgeführter Messungen an den gefertigten Aufbauten runden den Beitrag ab.}, author = {Löffler, Michael and Weiß, Manuel and Wiesgickl, Thomas and Rupitsch, Stefan}, doi = {10.1515/teme-2017-0028}, faupublication = {yes}, journal = {Technisches Messen}, keywords = {Amplified Piezo Actuator (APA); analytische Modellierung; numerische Modellierung}, peerreviewed = {Yes}, title = {{Untersuchung} analytischer und numerischer {Modelle} zur anwendungsspezifischen {Dimensionierung} eines {Amplified} {Piezo} {Actuators} ({Study} on analytical and numerical models for application-specific dimensioning of an {Amplified} {Piezo} {Actuator})}, year = {2017} } @inproceedings{faucris.123552484, abstract = {Überströmte Funktionsspalte von PKW-Karosserien können als wichtige Ursache strömungsmechanisch induzierten Schalls einen großen Einfluss auf den Schalldruckpegel im Innenraum ausüben. Besonders bedeutend ist der Funktionsspalt zwischen Fahrzeugdach und Heckklappe, der mit dem darunterliegenden Hohlraumvolumen einen Helmholtz-Resonator bildet. Der Schalldruckpegel im Resonanzvolumen des Heckklappenresonators wird ab Windgeschwindigkeiten von 140 km/h maßgeblich von der Form der stromaufwärtsliegenden Spaltkante beeinflusst [Schimmelpfennig, AIA-DAGA 2013, Meran]. So verursacht der fertigungsbedingte Biegeradius dieser Spaltkante bei einer Windgeschwindigkeit von 180 km/h rund 5 dB höhere Schalldruckpegel im Resonanzvolumen als eine scharfe, aufmodellierte Kante. Im Rahmen dieser Arbeit werden die strömungsmechanischen Zusammenhänge mithilfe eines generischen Heckklappenresonatormodells untersucht. Hierfür wird die Strömung im Spaltöffnungsbereich des Modells mit einem Hitzdraht ortsaufgelöst abgetastet. Die Schalldruckschwankungen innerhalb des Resonanzvolumens werden zeitsynchron zum Hitzdrahtsignal mit einem Mikrofon erfasst. Im Gegensatz zu selbsterhaltenden Anregungszuständen mit aktivem Rückkoppelmechanismus (self-sustaining oscillations) werden Anregungszustände ohne aktiven Rückkoppelmechanismus betrachtet. Die Messergebnisse in den Spaltöffnungsbereichen bei einer scharfen und einer abgerundeten vorderen Spaltkante werden hinsichtlich ihrer statistischen und frequenzaufgelösten Schwankungsgrößen verglichen. Hierbei zeigt sich ein signifikanter Einfluss der Form der vorderen Spaltkante. Neben der Analyse der Hitzdrahtmessungen werden Kohärenzanalysen zwischen Mikrofon- und Hitzdrahtsignal vorgestellt, um das Zusammenwirken von Strömung in der Spaltöffnung und Schalldruck im Resonanzvolumen näher zu beleuchten.}, address = {Berlin}, author = {Winter, Philipp and Weiß, Manuel and Wüst, Michael and Schimmelpfennig, Stefan and Lerch, Reinhard}, booktitle = {Fortschritte der Akustik 41 - DAGA 2015}, date = {2015-03-16/2015-03-19}, editor = {Deutsche Gesellschaft für Akustik e. V. (DEGA)}, faupublication = {yes}, isbn = {978-3939296089}, keywords = {Aeroakustik; aeroacoustics;}, pages = {596-599}, peerreviewed = {unknown}, publisher = {Deutsche Gesellschaft für Akustik e. V. (DEGA)}, title = {{Untersuchung} der aeroakustischen {Schallentstehung} an einem generischen {Heckklappenspaltmodell}}, venue = {Nürnberg}, year = {2015} } @inproceedings{faucris.117744044, abstract = {The aim of this paper is to present experimental and numerical investigations performed for the case of the flow around a square cylinder mounted on a wall. Our numerical scheme is based on a finite element (FE) formulation of Lighthill's analogy for the computation of flow induced noise. The flow is computed by a CFD code using the finite volume method (FVM) and the inhomogeneous wave equation according to Lighthill's analogy is solved by applying a finite element method (FEM). Our formulation allows for the flow as well as for the acoustic computation an independent and, for each physical field, optimal discretization. The scheme offers the possibility of a direct coupling in time domain as well as a sequential coupling in frequency domain. Correlation measurements are carried out in a low noise windtunnel for the pressure fluctuations on the wall, velocity characteristics of the flow and the recorded far field acoustic pressures. Finally, the measured and simulated results for the flow as well as for the acoustic field are discussed.}, address = {New York}, author = {Escobar Ramos, Max Eduardo and Hahn, Christian and Kaltenbacher, Manfred and Ali, Irfan and Becker, Stefan}, booktitle = {13th International Congress on Sound and Vibration 2006 (ICSV 13)}, date = {2006-07-02/2006-07-06}, faupublication = {yes}, isbn = {9781627481502}, note = {UnivIS-Import:2015-04-16:Pub.2006.tech.ITC.stmmec.valida}, pages = {5994-6001}, publisher = {Curran Associates, Inc.}, title = {{Validation} of computational aeroacoustics}, venue = {Wien, Österreich}, volume = {7}, year = {2006} } @article{faucris.114335364, abstract = {In order to precisely describe the behavior of ferromagnetic materials in rotating magnetic fields, vector hysteresis models are necessary. The extension of the Preisach model with vector methods is well known. Much research in this field is based on the Mayergoyz vector hysteresis model. The drawback of this kind of model is the computational effort for the additional integral in the vectorial Preisach operator. Therefore, much effort is being put into the development of efficient vector models. For the reason of computational efficiency, models have been developed that differ from the Preisach approach and are, for example, based on rotationally coupled step functions. We have proposed a very efficient Preisach based model before, which we called the rotational vector Preisach model. Here, we propose an extension of the rotational switching function of the mentioned model, which improves the model characteristics for arbitrary H-field trajectories. We also introduce a set of special vectorial minor loops for the general validation and comparison of vector models. We apply those H-field trajectories to isotropic materials like FeCo thin films as used in our micromechanical systems. The vectorial minor loops can readily be utilized to evaluate the model output and the results agree well with vectorial measurements.}, author = {Sutor, Alexander and Bi, Shasha and Lerch, Reinhard}, doi = {10.1007/s00339-013-7806-0}, faupublication = {yes}, journal = {Applied Physics A-Materials Science & Processing}, pages = {269-273}, peerreviewed = {Yes}, title = {{Validation} of the rotational vector {Preisach} model with measurements and simulations of vectorial minor loops}, volume = {112}, year = {2013} } @inproceedings{faucris.123348984, abstract = {Here, we report on the variation of material parameters of piezoceramic discs due to applied static and isotropic mechanical loads. Such mechanical loads frequently occur in piezoelectric sensor and actuator devices. In order to achieve reliable results from numerical simulation tools, these mechanical loads need to be taken into account. However, as alternative to considering the static and isotropic mechanical loads within the numerical simulation, we alter the material parameters of the piezoceramic appropriately. The material parameters for different mechanical loads are estimated by means of a mathematical Inverse Method. As the results for the thickness extensional mode of two different piezoceramic discs clearly show, primarily three material parameters are influenced by mechanical loads up to 2.0 MPa. (C) 2011 Published by Elsevier Ltd.}, author = {Rupitsch, Stefan and Ilg, Jürgen and Sutor, Alexander and Lerch, Reinhard}, doi = {10.1016/j.proeng.2011.12.356}, faupublication = {yes}, keywords = {Piezoceramics disc;Thickness extensional mode;Inverse Method;Electrical behavior;Mechanical load}, month = {Jan}, peerreviewed = {unknown}, publisher = {Elsevier BV}, title = {{Variation} of material parameters for the thickness extensional mode of piezoceramic discs in case of mechanical loading}, volume = {25}, year = {2011} } @article{faucris.123349424, abstract = {The quality of numerical simulations decisively depends on the used material models and their parameters. Only with good model descriptions, the behavior of components such as sensors and actuators can reliably be computed ahead. If magnetic materials are highly driven, which is necessary for an efficient use of an actuator material, hysteresis phenomena can no longer be ignored. Therefore, models are needed which can map this hysteresis phenomena, as well as correct values for the model parameters. Therefore, measurement techniques are necessary for the reliable determination of these model parameters. This paper discusses a measurement setup for magnetic vector hysteresis, the vector vibrating sample magnetometer (VVSM). The measurement setup is compared with other measurement methods. Furthermore, the parameters for a new vectorial hysteresis model are determined. The new model proposed by us is based on the classic Preisach model of hysteresis. This scalar model is extended by a rotation operator which maps a direction to each Preisach weight. The model is tested by comparing its performance to the VVSM measurements for different materials.}, author = {Sutor, Alexander and Kallwies, Jan and Lerch, Reinhard}, doi = {10.1524/teme.2012.0225}, faupublication = {yes}, journal = {Technisches Messen}, keywords = {Magnetometer;magnetization vector;vectorial measurement;hysteresis}, month = {Jan}, pages = {220-228}, peerreviewed = {Yes}, title = {{Vectorial} {Measuring} and {Modelling} of {Magnetic} {Hysteresis}}, volume = {79}, year = {2012} } @incollection{faucris.110151624, abstract = {Im vorhergehenden Forschungsvorhaben (im Folgenden „RENEBAT I“) kam weltweit erstmals ein stereo-wärmeoptisches Erfassungssystem zum Einsatz, mit dem die akustische Erfassung von Fledermäusen im Gondelbereich von Windenergieanlagen (im Folgenden „WEA“) validiert werden konnte. Dieses System ermöglicht es, die 3D-Flugbahnen von Fledermäusen im Gondelbereich von WEA zu bestimmen. Zusammen mit den akustischen Aufnahmen der in der Gondel installierten Detektoren können auf diese Weise Rückschlüsse auf die Reichweite der Detektoren gezogen werden. Im hier dargestellten Forschungsprojekt (im Folgenden „RENEBAT II“) erweiterten wir den aus RENEBAT I vorliegenden Wärmebilddatensatz um vier Erfassungsnächte. In jeweils zwei Nächten wurde die Fledermausaktivität in zwei verschiedenen Naturräumen erfasst. Aus den Wärmebilddaten der Naturräume D12 und D14 konnten insgesamt 18 bzw. 19 Flugbahnen innerhalb eines Abstands von 60 m zur Gondel vermessen werden (4468 bestimmte Fledermauspositionen). Die Analyse dieser Flugbahnen gab Hinweise auf wahrscheinliches Inspektionsverhalten von Fledermäusen in Gondelnähe. Außerdem wurde eine Kollision mit einem Rotorblatt aufgezeichnet. Im Fokus der Auswertung stand die Verteilung der Aufenthaltswahrscheinlichkeit von Fledermäusen im Rotorbereich von WEA. Die Kombination der Daten aus 2008 und 2012 zeigte eine exponentielle Abnahme der Aufenthaltsdichte mit zunehmendem Abstand zur Gondel. Die Aktivitätsdichte konvergierte dabei gegen einen Minimalwert, von dem wir annehmen, dass er der Aktivität im freien Lutraum entspricht. Basierend auf der gemessenen Verteilung berechneten wir Skalierungsfaktoren für das Schlagrisiko an WEA in Abhängigkeit vom Rotordurchmesser (falls dieser von dem der in RENEBAT I beprobten WEA abweicht). Die in RENEBAT I entwickelte Methode berechnet das Schlagrisiko für WEA mit etwa 70 m Rotordurchmesser. Bei WEA mit hiervon abweichendem Rotor würde daher das Schlagrisiko über- (bei weniger als 70 m Rotordurchmesser) bzw. unterschätzt (bei mehr als 70 m). Würde man bei der Korrektur für den Rotordurchmesser vereinfachend von einer Gleichverteilung der Fledermausaktivität im Rotorbereich ausgehen, so würde das Schlagrisiko z. B. für Anlagen mit 100 m Rotordurchmesser sehr hoch angesetzt werden. Im Unterschied dazu berücksichtigen wir bei den hier entwickelten Skalierungsfaktoren die Abnahme der Fledermausaktivität mit größerem Abstand zur Gondel, wodurch sich das geschätzte Schlagrisiko für große Anlagen deutlich reduziert. Wir validierten die berechneten Skalierungsfaktoren, indem wir z. B. die Aufnahmen vor und hinter der Gondel getrennt voneinander analysierten. Auch hier ergab sich eine Einleitung 83 exponentielle Abnahme der Fledermausdichte mit zunehmendem Abstand zur Gondel. Messungen der Schlagrate an Anlagen mit größerem Rotordurchmesser könnten zur weiteren Validierung der Ergebnisse beitragen.}, address = {Hannover}, author = {Hochradel, Klaus and Adomeit, Uwe and Heinze, Nicolai and Nagy, Martina and Stiller, Florian and Behr, Oliver}, booktitle = {Reduktion des Kollisionsrisikos von Fledermäusen an Onshore-Windenergieanlagen (RENEBAT II)}, editor = {Oliver Behr, Robert Brinkmann, Fränzi Korner-Nievergelt, Martina Nagy, Ivo Niermann, Michael Reich & Ralph Simon}, faupublication = {no}, peerreviewed = {unknown}, publisher = {Schriftenreihe Institut für Umweltplanung, Leibniz Universität Hannover}, series = {Umwelt und Raum}, title = {{Wärmeoptische} {3D}-{Erfassung} von {Fledermäusen} im {Rotorbereich} von {Windenergieanlagen}}, volume = {7}, year = {2015} } @incollection{faucris.264268818, abstract = {In real-world applications, wearable robots need to serve functional requirements, but also satisfy user demands. A systematic evaluation will require multidisciplinary benchmarking methods. Since user experience seems to be of distinct relevance, this paper analyzes how user experience influences wearable robots use and how it can be considered in benchmarking. Focus is set on potential metrics and how we could include them in human-centered benchmarking approaches.}, address = {Cham}, author = {Beckerle, Philipp}, booktitle = {Wearable Robotics: Challenges and Trends}, doi = {10.1007/978-3-030-69547-7{\_}95}, editor = {Juan C. Moreno, Jawad Masood, Urs Schneider, Christophe Maufroy, Jose L. Pons}, faupublication = {yes}, isbn = {978-3-030-69547-7}, note = {CRIS-Team Scopus Importer:2021-09-24}, pages = {591-595}, peerreviewed = {unknown}, publisher = {Springer Science and Business Media Deutschland GmbH}, series = {Biosystems and Biorobotics}, title = {{Wearable} {Robots} {Benchmarking}: {Comprehending} and {Considering} {User} {Experience}}, volume = {27}, year = {2022} } @article{faucris.287854645, abstract = {The Value Learning Task (VLT; e.g., Raymond & O'Brien, 2009) is widely used to investigate how acquired value impacts how we perceive and process stimuli. The task consists of a series of trials in which participants attempt to maximize accumulated winnings as they make choices from a pair of presented images associated with probabilistic win, loss, or no-change outcomes. The probabilities and outcomes are initially unknown to the participant and thus the task involves decision making and learning under uncertainty. Despite the symmetric outcome structure for win and loss pairs, people learn win associations better than loss associations (Lin, Cabrera-Haro, & Reuter-Lorenz, 2020). This learning asymmetry could lead to differences when the stimuli are probed in subsequent tasks, compromising inferences about how acquired value affects downstream processing. We investigate the nature of the asymmetry using a standard error-driven reinforcement learning model with a softmax choice rule. Despite having no special role for valence, the model yields the learning asymmetry observed in human behavior, whether the model parameters are set to maximize empirical fit, or task payoff. The asymmetry arises from an interaction between a neutral initial value estimate and a choice policy that exploits while exploring, leading to more poorly discriminated value estimates for loss stimuli. We also show how differences in estimated individual learning rates help to explain individual differences in the observed win-loss asymmetries, and how the final value estimates produced by the model provide a simple account of a post-learning explicit value categorization task.}, author = {Hao, Chenxu and Cabrera-Haro, Lilian E. and Lin, Ziyong and Reuter-Lorenz, Patricia A. and Lewis, Richard L.}, doi = {10.3758/s13415-022-01050-8}, faupublication = {yes}, journal = {Cognitive Affective & Behavioral Neuroscience}, note = {CRIS-Team WoS Importer:2023-01-20}, peerreviewed = {Yes}, title = {{Why} do valence asymmetries emerge in value learning? {A} reinforcement learning account}, year = {2022} } @inproceedings{faucris.116590584, author = {Heining, Martin and Sutor, Alexander and Lindenberger, Christoph and Buchholz, Rainer}, booktitle = {Tagungsband}, faupublication = {yes}, peerreviewed = {unknown}, title = {{Wireless} {Light} {Emitter} ({WLE}) zur internen {Beleuchtung} von {Photoreaktoren}}, year = {2013} }