检索结果-内蒙古大学图书馆

Heterodyne Standing-Wave Interferometer with Improved Phase Stability

Nanomanufacturing and Metrology 2021年第3期4卷 190-199页

作者： Ingo Ortlepp Jens-Peter Zollner Ivo W.Rangelow Eberhard Manske Institute of Process Measurement and Sensor Technology Technische Universitat IlmenauEhrenbergstraBe 2998693 IlmenauGermany Microelectronic and Nanoelectronic Systems Group Technische Universitat IlmenauIlmenauGermany Nanoscale Systems Group Technische Universitat IlmenauIlmenauGermany

This paper describes a standing-wave interferometer with two laser sources of different wavelengths,diametrically opposed and emitting towards each *** resulting standing wave has an intensity profile which is moving with a constant velocity,and is directly detected inside the laser beam by two thin and transparent photo *** first sensor is at a fixed position,serving as a phase reference for the second one which is moved along the optical axis,resulting in a frequency shift,proportional to the *** phase difference between both sensors is evaluated for the purpose of interferometric length measurements.

关键词： Standing wave Interferometer Heterodyne Ultrathin photo diode

来源：评论

学校读者我要写书评

暂无评论

Fiber Optic Current sensor Prototype for Low DC measurements in the Power Grid

Fiber Optic Current Sensor Prototype for Low DC Measurements...

引用

IEEE International Workshop on Applied measurements for Power systems (AMPS)

作者： Johannes Mandl Philipp Trampitsch Philipp Schachinger Dennis Albert Reinhard Klambauer Alexander Bergmann Institute of Electrical Measurement and Sensor Systems Graz University of Technology Graz Austria Institute of Electrical Power Systems Graz University of Technology Graz Austria OMICRON electronics GmbH Graz University of Technology Graz Austria

Our society is dependent on a continuous supply of electrical energy. Therefore, it is essential to closely monitor all occurring signals in the transmission grid to assess their effect on the grid's components and security of supply. In particular, the time course and distribution of direct currents such as geomagnetically induced currents is of great interest. In this paper, we report progress on the development of a fiber optic current sensor intended to observe direct currents on all three phases of a high-voltage power grid. The device exploiting the Faraday effect can be described in a theoretical model using Jones formalism. We calculated the sensor scale factor when using twisted single-mode and spun HiBi fiber as the sensing head, giving implications on the applicability of those fibers for a highly sensitive fiber optic current sensor. Laboratory results of the sensor prototype show a linear current relationship for currents below 1 A.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Optimizing Frequency Selection for Cole-Cole Model Parameter Extraction in Bioimpedance Spectroscopy Using CPE 17

Optimizing Frequency Selection for Cole-Cole Model Parameter...

引用

17th International Workshop on Impedance Spectroscopy, IWIS 2024

作者： Ouni, Cherif Ammar, Nour Kallel, Ahmed Yahia Horstmann, John Derbel, Nabil Fakhfakh, Ahmed Kanoun, Olfa Digital Research Centre of Sfax National School of Electronics and Telecommunications of Sfax Laboratory of Signals Systems Artificial Intelligence and Networks Sfax Tunisia Measurement and Sensor Technology Faculty of Electrical Engineering and Information Technology Chemnitz University of Technology Chemnitz09126 Germany National Engineering School of Sfax University of Sfax Control and Energy Management Laboratory Sfax3038 Tunisia Chemnitz University of Technology Chemnitz09126 Germany Electronic Devices of Micro and Nano Technique Faculty of Electrical Engineering and Information Technology Chemnitz University of Technology Chemnitz09126 Germany

ISBN: (纸本)9798331507626

Wearable bioimpedance spectroscopy (BIS) devices are becoming increasingly popular due to their portability and low power consumption. However, improving power efficiency remains a significant challenge. One proposed solution is to reduce the number of excitation frequencies in the stimulation signal. This study investigates how reducing the number of used frequencies affects bioimpedance spectroscopy performance through simulations using synthetic data derived from a Cole-Cole model incorporating a Constant Phase Element (CPE). Simulations were conducted at various noise levels to evaluate how noise impacts the relationship between frequency and impedance. The results indicate a correlation between the number of frequencies used in BIS and the accuracy of CPE parameter extraction. This is particularly evident for α parameters of 0.8 and higher. Conversely, lowering the α value increases errors, even when a higher number of frequencies is used. © 2024 IEEE.

关键词： Image coding

来源：评论

学校读者我要写书评

暂无评论

Segment-Anything Models Achieve Zero-shot Robustness in Autonomous Driving

arXiv

引用

arXiv 2024年

作者： Yan, Jun Wang, Pengyu Wang, Danni Huang, Weiquan Watzenig, Daniel Yin, Huilin The College of Electronics and Information Engineering Tongji University Shanghai201804 China The Institute of Electrical Measurement and Sensor Systems Graz University of Technology The Virtual Vehicle Research Graz8010 Austria

Semantic segmentation is a significant perception task in autonomous driving. It suffers from the risks of adversarial examples. In the past few years, deep learning has gradually transitioned from convolutional neural network (CNN) models with a relatively small number of parameters to foundation models with a huge number of parameters. The segment-anything model (SAM) is a generalized image segmentation framework that is capable of handling various types of images and is able to recognize and segment arbitrary objects in an image without the need to train on a specific object. It is a unified model that can handle diverse downstream tasks, including semantic segmentation, object detection, and tracking. In the task of semantic segmentation for autonomous driving, it is significant to study the zero-shot adversarial robustness of SAM. Therefore, we deliver a systematic empirical study on the robustness of SAM without additional training. Based on the experimental results, the zero-shot adversarial robustness of the SAM under the black-box corruptions and white-box adversarial attacks is acceptable, even without the need for additional training. The finding of this study is insightful in that the gigantic model parameters and huge amounts of training data lead to the phenomenon of emergence, which builds a guarantee of adversarial robustness. SAM is a vision foundation model that can be regarded as an early prototype of an artificial general intelligence (AGI) pipeline. In such a pipeline, a unified model can handle diverse tasks. Therefore, this research not only inspects the impact of vision foundation models on safe autonomous driving but also provides a perspective on developing trustworthy AGI. The code is available at: https://***/momo1986/robust_sam_iv. © 2024, CC BY.

关键词： Semantic Segmentation

来源：评论

学校读者我要写书评

暂无评论

Refractive index characterization and modeling of polymerization-dependent refractive index variations in two-photon polymerization resins

Optics Continuum

引用

Optics Continuum 2025年第5期4卷 996-1005页

作者： Golf Feigl Daniel Zaugg Jakob W Hinum-Wagner Samuel M Hörmann Alexer Bergmann Graz University of Technology Institute of Electrical Measurement and Sensor Systems Inffeldgasse 33 8010 Graz Austria Christian Doppler Laboratory for Structured Matter Based Sensing 8010 Graz Austria ams OSRAM Group Tobelbader Strasse 30 8141 Premstaetten Austria

Two-photon polymerization (2PP) is a cutting-edge technique for fabricating precise micro- and nanostructures, with applications in photonics, biomedical engineering, and micro-optics. A critical factor influencing the optical performance of 2PP-fabricated structures is the refractive index (RI) of the printed parts. This study analyzes the refractive indices of three resins developed by UpNano GmbH . Using a Pulfrich refractometer, dispersion curves of the polymerized resins were measured across the visible to near-infrared spectrum (450 nm – 1550 nm), and temperature-dependent RI behavior was characterized for both liquid and polymerized resins (15°C – 50°C). The RI of the polymerized resins ranges from 1.496 to 1.567. What we believe to be a novel model was developed to account for periodic RI fluctuations inherent in 2PP-printed parts due to voxel-based polymerization patterns. The model fits experimental data well and provides additional insights into the degree of polymerization within printed samples. These findings not only enhance understanding of the optical properties of 2PP-fabricated structures but also suggest opportunities for tailoring materials for gradient-index optics and other advanced optical applications.

关键词： Femtosecond lasers Gradient index optics Optical components Optical properties Refractive index Ultrafast lasers

来源：评论

学校读者我要写书评

暂无评论

Design optimization of silicon nitride-based micro-ring resonator systems in a CMOS mass production environment 7

Design optimization of silicon nitride-based micro-ring reso...

引用

Integrated Optics: Design, Devices, systems and Applications VII 2023

作者： Hinum-Wagner, Jakob Wilhelm Buchberger, Anton Schmidt, Christoph Schörner, Christian Rist, Desiree Hoermann, Samuel Marko Feigl, Gandolf Malicka, Iga Janka, Stephan Kraft, Jochen Bergmann, Alexander Institute of Electrical Measurement and Sensor Systems Graz University of Technology Inffeldgasse 33 Graz8010 Austria Institute of Analytical Chemistry and Food Chemistry Graz University of Technology Stremayrgasse 9 Graz8010 Austria ams-OSRAM AG Tobelbaderstraße 30 Premstaetten8141 Austria ams-OSRAM International GmbH Leibnitzstraße 4 Regensburg93055 Germany

ISBN: (数字)9781510662711

ISBN: (纸本)9781510662704

Micro-ring resonators (MRR) are basic photonic components, which serve as crucial building blocks for a variety of devices, e.g. integrated sensors, external cavity lasers, and high speed photonic data transmitters. Silicon nitride photonic platforms are particularly appealing in this field o f a pplication, s ince t his w aveguide material enables on-chip photonic circuitry with (ultra-) low losses in the NIR as well as across the whole visible spectral range. In this contribution we investigate key performance properties of MRRs in the wavelength range around 850 nm, such as free spectral range (FSR), quality factor (Q factor) and extinction ratio. We systematically investigate a large parameter space given by the MRR radii, coupling gaps between ring and bus waveguide, as well as waveguide width. Furthermore, we compare key properties such as the Q factor between low pressure chemical vapor deposition (LPCVD) and plasma enhanced chemical vapor deposition (PECVD) Si3N4 platforms and find enhanced values for LPCVD ring resonators reaching nearly a Q factor of *** fabrication is carried out with standard CMOS foundry equipment, utilizing photolithography and reactive ion etching on 250 nm thick silicon nitride films. A s c ladding m aterial, h igh d ensity P ECVD s ilicon o xide i s d eposited p rior t o the waveguide onto bare silicon and a sputtered oxide serves as upper cladding. With this process toolbox full CMOS backend compatibility is achieved when considering only PECVD Si3N4 waveguide material. In terms of manufacturability, special focus is put on the die-to-die as well as on wafer-to-wafer variability of the performance parameters, which is crucial when considering mass production of MRR devices. Finally, the experimental findings are compared to finite difference time domain (FDTD) simulations of the MRR circuits revealing excellent agreement when considering the manufacturing variability. © 2023 SPIE.

关键词： Silicon nitride

来源：评论

学校读者我要写书评

暂无评论

Microcontroller-Based Implementation of the DRT for Bioimpedance Spectroscopy 22

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

引用

22nd IEEE International Multi-Conference on systems, Signals and Devices, SSD 2025

作者： Trabelsi, Ayoub Ammar, Nour Ouni, Cherif Kallel, Ahmed Yahia Fakhfakh, Ahmed Sahnoun, Salwa Derbel, Nabil Kanoun, Olfa Professorship Measurement and Sensor Technology Chemnitz University of Technology Chemnitz 09126 Germany Digital Research Centre of Sfax National School of Electronics and Telecommunications of Sfax Technopole of Sfax Laboratory of Signals Systems Artificial Intelligence and Networks Ons City 3021 Tunisia School of Sfax University of Sfax Control and Energy Management Laboratory Sfax 3038 Tunisia

ISBN: (纸本)9798331542726

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. © 2025 IEEE.

关键词： Bioimpedance Spectroscopy Distribution of Relaxation Times (DRT) equivalent circuit impedance spectroscopy microcontroller non-negative least squares Tikhonov regularization

来源：评论

学校读者我要写书评

暂无评论

Compact Inverse-Designed Metalens for Millimeter-Wave Field Enhancement

Compact Inverse-Designed Metalens for Millimeter-Wave Field ...

引用

IEEE Photonics Conference (IPC)

作者： Christoph Schmidt Michael Töfferl Alexander Schossmann Peter Banzer Alexander Bergmann Institute for Measurement and Sensor Systems Graz University of Technology Graz Austria Christian Doppler Laboratory for Structured Matter Based Sensing Graz Austria Department of Physics University of Graz Graz Austria

ISBN: (数字)9798350361957

ISBN: (纸本)9798350361964

Enhancing fields is an important task in millimeter-wave applications, such as nondestructive microwave inspection, metamaterial sensing applications, or millimeter-wave imaging. This demand for compact yet high-performance devices for field enhancement operating in the millimeter-wave regime has led to innovative approaches regarding lens design. State-of-the-art lens designs in this wavelength regime tend to be bulky and operate in the far field, making them unsuitable for small form factor applications. In this context, formulating the required functionality and algorithmically looking for the desired material topology is an inversion of the standard approach. This paper presents an inverse-designed field-amplifying metalens operating in the near field of a 60GHz patch antenna. With a size of about three times the wave length, the given structure promises good performance while maintaining a smaller form factor than conventional solutions. It yields an enhancement of the power amplitude by over 7dB.

关键词： Millimeter wave technology Rapid prototyping Reproducibility of results Topology sensors Printers Polymers Microwave filters Standards Lenses

来源：评论

学校读者我要写书评

暂无评论

Generalization of Reflection Modeling in Complex Cable Structure with Impedance Mismatches

Generalization of Reflection Modeling in Complex Cable Struc...

引用

Impedance Spectroscopy (IWIS), International Workshop on

作者： Dhia Haddad Najoua Essoukri Ben Amara Olfa Kanoun Professorship Measurement and Sensor Technology Technische Universität Chemnitz Chemnitz Germany 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

Cable networks are essential in modern systems, but they can develop defects due to environmental factors or wear, leading to signal degradation or reduced performance. These defects cause signal reflections in transmission lines due to impedance mismatches, either within the cables or between the cables and their port loads. Such reflections can result from junctions, soft faults (partial impedance changes), or hard faults, i.e., open or short circuits. Diagnosing these faults, especially using Time-Domain Reflectometry (TDR), requires accurately modeling how impedance mismatches affect signal reflections. This paper presents a model that takes a comprehensive approach to addressing various sources of impedance mismatches. It covers junctions, soft and hard faults, and mismatches between cables and connected devices. The model's thoroughness is evident in its ability to handle complex scenarios such as heterogeneous junctions, soft faults, multi-path reflections, input port reflections, and multi-load reflections. Additionally, it evaluates signal reflection measurability based on the components of the propagation path, further enhancing its robustness. The model's accuracy is validated through simulations using the distributed RLCG cable model, comparing predicted reflection values with simulated signals. The results show strong agreement, confirming the model's effectiveness in diagnosing faults in complex cable networks. This should instill confidence in the model's practical application, as it accurately correlates signal reflections with specific defects, paving the way for efficient fault diagnosis.

关键词： Power cables Predictive models Transmission line measurements Reflection Mathematical models Impedance Circuit faults Junctions Integrated circuit modeling Load modeling

来源：评论

学校读者我要写书评

暂无评论

Feature Engineering for Accurate Low-Power Electrical Impedance Tomography in Hand Sign Recognition

Feature Engineering for Accurate Low-Power Electrical Impeda...

引用

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

作者： Bilel Ghoul Rim Barioul 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

ISBN: (数字)9798331542726

ISBN: (纸本)9798331542733

Achieving high classification accuracy from raw measurements in Electrical Impedance Tomography (EIT) for hand sign recognition is a significant challenge due to the inherent ill-posed nature of the corresponding inverse problem to solve. Energy consumption is an issue, especially for wearable devices, so there is a growing preference to measure EIT with fewer electrodes or fewer current injections. In a previous study, we demonstrated that an 8-electrode hand gesture recognition system could achieve high accuracy with only 5 current injections instead of 8, resulting in significant power savings. In this study, we investigate feature extraction and selection techniques to improve the classification accuracy in the low-power EIT system based on less measurements. We evaluate the performance of 12 statistical features by analyzing the Feature Importance (FI) and identify 8 features with non-zero values: WL, MAV, Kurtosis, VORDER, DASDV, RMS, P2P and VAR. Using K-Nearest Neighbour (KNN), a comparative classification is performed using subsets of the best ranked features ranging from 2 to 8. Compared to the 96% accuracy achieved with raw data, our solution achieves 99.8% accuracy with the 8 extracted features. The results show that feature engineering significantly improves classification accuracy compared to the use of raw data.

关键词： Hands Performance evaluation Electrical impedance tomography Reactive power Accuracy Current measurement Nearest neighbor methods Feature extraction Kurtosis Wearable devices

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：