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2021 IEEE Green Energy and Smart systems Conference, IGESSC 2021

作者： Buchroithner, Armin Presmair, Rupert Haidl, Peter Wegleiter, Hannes Thormann, Bernd Kienberger, Thomas Auer, Peter Domitner, Josef Graz University Of Technology Institute Of Electrical Measurement And Sensor Systems Graz Austria Montanuniversität Leoben Chair Of Energy Network Technology Leoben Austria Graz University Of Technology Institute Of Materials Science Joining And Forming Graz Austria

ISBN: (纸本)9781665434560

Increasing the share of battery electric mobility in the transport mix, while at the same time integrating more renewable volatile energy sources in the grid, brings along a variety of challenges such as possible power quality, voltage and grid stability issues. Deploying decentralized energy storage devices in electric vehicle (EV) fast charging stations as buffer storage is one way to mitigate these problems and help store renewable energy in the grid. This paper describes a system integrating a high performance flywheel energy storage system (FESS) in a fully automated fast charging station. A holistic approach is pursued, determining the FESS's energetic target properties by analyzing user behavior in a variety of use cases in conjunction with in-depth grid simulations. Based on these data, a FESS design is proposed and approaches to reach the desired energetic target properties are discussed. Critical components are presented with a focus on CFRP rotor design, as it is crucial for achieving the required energy content at lowest specific cost. © 2021 IEEE.

关键词： Buffer storage

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Verification of the mechanical integrity of regenerated fiber Bragg gratings (RFBGs) by shaker tests for their use as high-temperature sensors in gas turbines 27

Verification of the mechanical integrity of regenerated fibe...

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27th International Conference on Optical Fiber sensors, OFS 2022

作者： Stadler, Andrea Buchfellner, Fabian Zeisberger, Andreas Jakobi, Martin Koch, Alexander W. Roths, Johannes Photonics Laboratory Munich University of Applied Sciences Lothstr. 34 Munich80335 Germany MTU Aero Engines AG Dachauer Str. 665 Munich80995 Germany Institute for Measurement Systems and Sensor Technology Technical University of Munich Theresienstr. 90 Munich80333 Germany

Shaker tests were performed with RFBGs in the range of 0.1 - 10 kHz at 4.5 g acceleration. In successive tests, the RFBGs showed no failures, and the vibrations had only a limited influence on the measured temperature... 详细信息

ISBN: (纸本)9781957171142

关键词： Gas turbines

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Investigation of the surface integrity when cryogenic milling of Ti-6Al-4V using a sub-zero metalworking fluid

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Procedia CIRP 2022年 108卷 25-30页

作者： Kevin Gutzeit Georgis Bulun Gerhard Stelzer Benjamin Kirsch Jörg Seewig Jan C. Aurich Institute for Manufacturing Technology and Production Systems TU Kaiserslautern Gottlieb-Daimler-Str. 67663 Kaiserslautern Germany Institute for Measurement and Sensor Technology TU Kaiserslautern Gottlieb-Daimler-Str. 67663 Kaiserslautern Germany

In this paper a novel cooling strategy is presented using a sub-zero metalworking fluid when milling Ti-6Al-4V. The metalworking fluid, composed of water and ethane-1,2-diol, was applied to the process at varied supply temperatures. An analysis of the occurring forces and temperatures, as well as the resulting surface integrity, is carried out. The surface integrity is characterized by microhardness measurements in the surface layer of the workpiece. Additionally, the surface topography is characterized using optical measuring techniques. The results are compared to those obtained using dry milling and when using a conventional cryogenic CO 2 cooling strategy.

关键词： cryogenic machinig milling cooling strategy surface integrity Ti-6Al-4V

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A Low-Power Voltage-Controlled Current Source for Wearable Bioimpedance Applications

A Low-Power Voltage-Controlled Current Source for Wearable B...

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IEEE SSD International Multi-Conference on systems, Signals and Devices

作者： Cherif Ouni Bilel Ghoul Hamdi Al-Shaikhli Jumana Ma'touq Ahmed Fakhfakh Olfa Kanoun Measurement and Sensor Technology Faculty of Electrical Engineering and Information Technology Chemnitz University of Technology Chemnitz Germany Laboratory of Signals Systems Artificial Intelligence and Networks Digital Research Centre of Sfax National School of Electronics and Telecommunications of Sfax Sfax Tunisia Department of Biomedical Engineering School of Applied Medical Sciences (SAMS) German Jordanian University Amman Jordan

ISBN: (数字)9798331542726

ISBN: (纸本)9798331542733

Bioimpedance spectroscopy (BIS) has gained prominence as a non-invasive diagnostic tool for characterizing biological tissues, offering critical insights into physiological and pathological conditions. At the core of BIS systems lies the Voltage-Controlled Current Source (VCCS), which is essential for ensuring precise and stable current delivery across varying load conditions. This paper investigates a modified dual Howland configuration with load-in-loop compensation designed for low-power applications. By operating at reduced supply voltages (5V) instead of the conventional ±12V, the proposed design addresses the limitations of existing VCCS circuits in portable and wearable medical devices. The study evaluates the performance of the proposed VCCS circuit in a wide range of frequencies (50 kHz to 1 MHz), load conditions (1000 to 18kO), and input signal types (sine, multi-sine, and sine-sweep). Key findings demonstrate stable current output, efficient power consumption, and robust performance at reduced power levels, making it suitable for bioimpedance applications requiring portable operation.

关键词： Performance evaluation Spectroscopy Pathology Power demand Medical devices Circuits Bioimpedance Physiology Wearable devices Voltage control

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Microcontroller-Based Implementation of the DRT for Bioimpedance Spectroscopy

Microcontroller-Based Implementation of the DRT for Bioimped...

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IEEE SSD International Multi-Conference on systems, Signals and Devices

作者： Ayoub Trabelsi Nour Ammar Cherif Ouni Ahmed Yahia Kallel Ahmed Fakhfakh Salwa Sahnoun Nabil Derbel Olfa Kanoun Professorship Measurement and Sensor Technology Chemnitz University of Technology Chemnitz Germany Laboratory of Signals Systems Artificial Intelligence and Networks Digital Research Centre of Sfax National School of Electronics and Telecommunications of Sfax Technopole of Sfax Ons City Tunisia Control and Energy Management Laboratory School of Sfax University of Sfax Sfax Tunisia

ISBN: (数字)9798331542726

ISBN: (纸本)9798331542733

Bio-Impedance Spectroscopy (BIS) is a non-invasive method for characterizing biological systems. Converting impedance spectra into the distribution of relaxation times (DRT) allows the separation of overlapping effects without relying on equivalent circuits as impedance models. This transformation significantly reduces signal processing time from several seconds to milliseconds. Therefore, there is a significant need for embedded solutions that implement DRT in microcontroller-based systems. Following a detailed evaluation of various methodologies, NNLS combined with Tikhonov regularization was selected for its ability to achieve an 83.33% reduction in execution time. This paper presents a novel approach for implementing this optimized DRT extraction in STM32-based embedded systems. The novel implementation achieves processing times of 74 ms for a 101-frequency data set on the STM32 while utilizing only 2.69 kB of RAM. The system successfully extracts DRT peaks with different magnitudes and their relative relaxation times for 51-frequency and 101-frequency datasets. We demonstrate equivalent circuit parameter extraction with relative errors below 3.5%. This work establishes a foundation for portable BIS analysis, with potential applications in areas such as medical diagnostics, food state characterization, and plant monitoring.

关键词： Spectroscopy Embedded systems Microcontrollers Signal processing algorithms Random access memory Bioimpedance Biological systems Signal processing Impedance Equivalent circuits

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Reducing Injections in Low-Power Electrical Impedance Tomography for Hand Sign Recognition

Reducing Injections in Low-Power Electrical Impedance Tomogr...

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Impedance Spectroscopy (IWIS), International Workshop on

作者： Bilel Ghoul Rim Barioul Mariem Hafsa Salwa Sahnoun Ahmed Fakhfakh Olfa Kanoun Measurement and Sensor Technology Faculty of Electrical Engineering and Information Technology Chemnitz University of Technology Chemnitz Germany Laboratory of Signals Systems Artificial Intelligence and Networks Digital Research Centre of Sfax National School of Electronics and Telecommunications of Sfax Technopole of Sfax Ons City Tunisia LATIS- Laboratory of Advanced Technology and Intelligent Systems Université de Sousse Ecole Nationale d'Ingénieurs de Sousse Sousse Tunisie

ISBN: (数字)9798331507626

ISBN: (纸本)9798331507633

Electrical Impedance Tomography (EIT) is increasingly being used to recognize hand signs due to its internal sensing capabilities. EIT systems operate by injecting a lowamplitude electrical current into the forearm through a set of electrodes and recording the resulting voltages for signal processing. However, this method can result in high power consumption in wearable hand gesture recognition applications due to the current injection-based principle. To overcome this limitation, our investigation focuses on reducing the power consumption of EIT systems by minimizing the number of injected currents. In this study, we propose an injection reduction approach based on ambiguity analysis and the reduction of non-relevant voltage readings. As a result, the proposed method eliminates 3 out of 8 current injections, leading to a 37.5 % reduction in power consumption. This decreases energy usage by 22.5 mW per measurement for a current amplitude of ${150} \mu \mathrm{A}$ over 10 trials. Further, acquisition time was reduced from 1 second to 0.6 seconds. The classification accuracy using the KNN classifier reached 99 % with full measurements and 96 % with reduced injections. Moreover, a comparative analysis of the reduced injections to forearm anatomy is performed. It demonstrates that bones and high-density muscle areas can affect the current flow and result in inaccurate measurements. These findings demonstrate the potential for reducing current injections in EIT to produce more energy-efficient wearable hand sign recognition systems.

关键词： Hands Electrodes Electrical impedance tomography Electric potential Power demand Accuracy Current measurement Muscles Nearest neighbor methods Impedance

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Quantitative phase imaging through an ultra-thin lensless fiber endoscope

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Light(Science & Applications) 2022年第8期11卷 1843-1852页

作者： Jiawei Sun Jiachen Wu Song Wu Ruchi Goswami Salvatore Girardo Liangcai Cao Jochen Guck Nektarios Koukourakis Juergen W.Czarske Laboratory of Measurement and Sensor System Technique(MST) TU DresdenHelmholtzstrasse 1801069DresdenGermany Competence Center for Biomedical Computational Laser Systems(BIOLAS) TU DresdenDresdenGermany State Key Laboratory of Precision Measurement Technology and Instruments Department of Precision InstrumentsTsinghua University100084BeijingChina Institute for Integrative Nanosciences IFW DresdenHelmholtzstraße 2001069DresdenGermany Max Planck Institute for the Science of Light&Max-Planck-Zentrum für Physik und Medizin 91058ErlangenGermany Cluster of Excellence Physics of Life TU DresdenDresdenGermany Institute of Applied Physics TU DresdenDresdenGermany

Quantitative phase imaging(QPI)is a label-free technique providing both morphology and quantitative biophysical information in ***,applying such a powerful technique to in vivo pathological diagnosis remains ***-core fiber bundles(MCFs)enable ultra-thin probes for in vivo imaging,but current MCF imaging techniques are limited to amplitude imaging *** demonstrate a computational lensless microendoscope that uses an ultra-thin bare MCF to perform quantitative phase imaging with microscale lateral resolution and nanoscale axial sensitivity of the optical path *** incident complex light field at the measurement side is precisely reconstructed from the far-field speckle pattern at the detection side,enabling digital refocusing in a multi-layer sample without any mechanical *** accuracy of the quantitative phase reconstruction is validated by imaging the phase target and hydrogel beads through the *** the proposed imaging modality,three-dimensional imaging of human cancer cells is achieved through the ultra-thin fiber endoscope,promising widespread clinical applications.

关键词： fiber phase thin

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Evaluation of Adjacent and Opposite Current Injection Patterns for 3D Image Reconstruction of the Human Lung Based on a Realistic Model

Evaluation of Adjacent and Opposite Current Injection Patter...

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Impedance Spectroscopy (IWIS), International Workshop on

作者： Mejda Bouchhima Oumaima Bader Mariem Hafsa Salwa Sahnoun Najoua Essoukri Ben Amara Olfa Kanoun National School of Electronics and Telecommunications of Sfax University of Sfax Sfax Tunisia Professorship Measurement and Sensor Technology Chemnitz University of Technology Chemnitz Germany Université de Sousse Ecole Nationale d'Ingénieurs de Sousse LATIS - Laboratory of Advanced Technology and Intelligent Systems Sousse Tunisie Laboratory of Signals Systems Artificial Intelligence and Networks Digital Research Center of Sfax Sfax Tunisia

ISBN: (数字)9798331507626

ISBN: (纸本)9798331507633

Electrical Impedance Tomography (EIT) is a non-invasive, radiation-free imaging technique that can be used for 2D lung imaging. However, 2D EIT has a simplified geometric assumption, which neglects the 3D dynamic lung changes. This study develops a realistic 3D geometrical model including the lungs and thoracic cavity For EIT analysis. Finite Element (FE) models are generated for forward calculation and image reconstruction using an optimized Gauss-Newton (GN) algorithm. Two common current injection patterns - Adjacent and Opposite - are compared. Results show that using the lung-refined model with prior knowledge of the lungs' elements, GN converges with a Pearson correlation (r) of 0.9707 for the opposite pattern, higher than the adjacent pattern which reaches 0.9703. The second metric is the mean squared errors (MSE) between boundary voltages (BV) from reconstructed images and ground truth. It reaches $5.3965 \cdot 10^{-4},5.3963\cdot 10^{-4}$ , and $1.027{6}\cdot 10^{-12}$ for the Opposite pattern, respectively, for an empty cavity, lung-refined mesh without, and with prior knowledge of the lungs' elements. The results prove the efficiency of the Opposite injection pattern compared to the Adjacent pattern. These findings highlight the importance of injection patterns and the benefits of using a lung-refined mesh with prior knowledge of the lungs' elements for more accurate reconstructions.

关键词： Electrical impedance tomography Solid modeling Spectroscopy Three-dimensional displays Accuracy Correlation Lungs Imaging Finite element analysis Image reconstruction

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Fast processing and classification of epileptic seizures based on compressed EEG signals

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Computers in Biology and Medicine 2025年 184卷 109346-109346页

作者： Djemal, Achraf Kallel, Ahmed Yahia Ouni, Cherif El Baccouch, Rihem Bouchaala, Dhouha Kammoun Feki, Fatma Charfi Triki, Chahnez Fakhfakh, Ahmed Kanoun, Olfa Professorship Measurement and Sensor Technology Chemnitz University of Technology Chemnitz Germany Child Neurology Department Hedi Chaker Sfax University Hospital and Research Laboratory LR19ES15 University of Sfax Sfax Tunisia Laboratory of Signals Systems Artificial Intelligence and Networks Digital Research Centre of Sfax National School of Electronics and Telecommunications of Sfax Sfax3021 Tunisia

The diagnosis of epilepsy based on visual inspection of electroencephalogram (EEG) signals is inherently complex and prone to error, even for physicians, mainly due to the large number of signals involved and the variability between individuals. These same challenges make the development of portable epilepsy diagnostic systems for everyday use difficult. Key obstacles include the immense complexity of signal processing and the inherent ambiguity in accurately classifying disease. For these reasons, we propose in this paper the deployment of compressive sensing to condense EEG signals while preserving relevant information, allowing seizure classification based on systematically selected features of the reconstructed signals. Based on a dataset comprising EEG recordings from 13 epileptic patients with various seizure types, we explore the deployment of the discrete cosine transform (DCT) and random matrix multiplication for compression ratios ranging from 5% to 70%, balancing data reduction with signal fidelity. Following the extraction of relevant features, selection was performed based on mutual information and a correlation matrix to preserve only the most relevant features for analysis. For classification, following a comparison of adequate machine learning models, XGBoost is chosen as it realizes a classification accuracy of 98.78%. The CS method was implemented on an STM32 microcontroller and a Raspberry Pi for reconstruction and classification, to demonstrate feasibility as an embedded system. At 70% compression, significant improvements have been observed: 70% file size reduction, 84% decrease in transmission time (from 2518.532s to 400.392s), and substantial energy savings (e.g., from 11.5±0.707 mWh to 4.5±0.707 mWh for Patient 12). Thereby, the signal quality was maintained with PSNR of 16.15±3.98 and Pearson correlation coefficient of 0.68±0.15. The proposed system highlights the potential for efficient, portable, real-time epilepsy diagnosis systems that a

关键词： Cosine transforms

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Full-Waveform Modeling for Time-of-Flight measurements based on Arrival Time of Photons

arXiv

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arXiv 2022年

作者： Fink, Maximilian Schardt, Michael Baier, Valentin Wang, Kun Jakobi, Martin Koch, Alexander W. Technical University of Munich Department of Electrical and Computer Engineering Institute for Measurement Systems and Sensor Technology Munich80333 Germany Blickfeld GmbH Munich80339 Germany

Modern LiDAR sensors find increasing use in safety-critical applications. Therefore, highly accurate modeling of the system’s behavior under demanding environmental conditions is necessary. In this paper, we present a modular structure to accurately simulate the amplified raw detector signal of a direct time-of-flight LiDAR system for coaxial transmitter-receiver optics. Our model describes, a measurement system based on standard optical components and a detector able of converting single photons to an electrical signal. To verify the model’s predictions, single-point measurements for targets of different reflectivity at defined distances were performed. Statistical analysis shows an R-squared value greater than 0.990 for simulated and measured signal amplitude levels. Noise modeling shows good accordance with the performed measurements for different target irradiance levels. The presented results have a guiding significance in the modeling of the complex signal processing chain of LiDAR systems, as it enables the prediction of key parameters of the system early in the development process. Hence, unnecessary costs by design flaws can be mitigated. The modular structure allows easy adaption for arbitrary LiDAR systems. Copyright © 2022, The Authors. All rights reserved.

关键词： Optical radar

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