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20th International Multi-Conference on systems, Signals and Devices, SSD 2023

作者： Alwaz, Youssef Bader, Oumaima Ben Amara, Najoua Essoukri Kanoun, Olfa University of Sousse National Engineering School of Sousse Sousse Tunisia Université de Sousse Ecole Nationale d'Ingénieurs de Sousse LATIS- Laboratory of Advanced Technology and Intelligent Systems Sousse4023 Tunisia Technische Universität Chemnitz Measurement and Sensor Technology Chemnitz09111 Germany

ISBN: (纸本)9798350332568

Electrical Impedance Tomography (EIT) for lung monitoring reflects the internal conductivity distribution of human tissues based on the boundary voltages that are measured through given electrodes. The electrodes are placed around the human chest. A low-amplitude current is injected through driving electrodes, and the boundary voltages are measured through other electrodes. In this context, this work has elaborated a strategy for the design of a 3D geometry of the human thorax based on sequential Computed Tomography (CT) scans. This geometry will be used for the simulation and analysis of the EIT measurement. Image segmentation has been used to extract the contour within different layers of the CT scans to form the final 3D geometry of the chest containing the lungs and the thorax. The generated geometry was later meshed and repaired. Mesh properties were controlled through the Skewness quality metric. A multi-layered design has been elaborated to mimic different human chest layers such as body fluid, muscle, and skin resulting in three models. These models had given the accuracy of 62%, 63%, and 65% of skewed elements relative to the existing volume. Later on, the electrodes were placed on the thorax geometry for EIT forward simulation, and the effect of the multi-layered model has been investigated. © 2023 IEEE.

关键词： Finite element method

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Reducing Injections in Low-Power Electrical Impedance Tomography for Hand Sign Recognition 17

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

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17th International Workshop on Impedance Spectroscopy, IWIS 2024

作者： Ghoul, Bilel Barioul, Rim Hafsa, Mariem Sahnoun, Salwa Fakhfakh, Ahmed Kanoun, Olfa Chemnitz University of Technology Faculty of Electrical Engineering and Information Technology Measurement and Sensor Technology Chemnitz09126 Germany National School of Electronics and Telecommunications of Sfax Technopole of Sfax Laboratory of Signals Systems Artificial Intelligence and Networks Digital Research Centre of Sfax Ons City 3021 Tunisia Université de Sousse Ecole Nationale d'Ingénieurs de Sousse LATIS- Laboratory of Advanced Technology and Intelligent Systems Sousse4023 Tunisia

ISBN: (纸本)9798331507626

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 μ 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. © 2024 IEEE.

关键词： Nearest neighbor search

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Single-sized phase-change metasurfaces for dynamic information multiplexing and encryption

arXiv

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arXiv 2024年

作者： Liu, Tingting Li, Jie Xiao, Shuyuan Institute for Advanced Study Nanchang University Nanchang330031 China Optoelectronic Sensor Devices and Systems Key Laboratory of Sichuan Provincial University College of Optoelectronic Engineering Chengdu University of Information Technology Chengdu610225 China

Optical metasurfaces empower us to manipulate the electromagnetic space and control light propagation at the nanoscale, offering a powerful tool to achieve modulation of light for information processing and storage. In this work, we propose a phase-change metasurface to realize dynamic multiplexing and encryption of near-field information. Based on the orientation degeneracy and polarization control governed by Malus’s law, we elaborately design the orientation distribution of Sb2S3 meta-atoms with the same dimension to simultaneously satisfy the amplitude modulation requirements of different channels. Using the corresponding polarization control as decoding keys, three different nanoprinting images can be displayed, and these multiplexed images can be switched on and off by leveraging the reversible tunability of the Sb2S3 meta-atoms between the amorphous and crystalline states. With the unparalleled advantages of ultra-compactness, simple design strategy, high information density and security, the proposed metasurfaces afford promising prospects for high-end applications in ultracompact and intelligent dynamic display, high-dense optical data storage, optical information encryption, etc. Copyright © 2024, The Authors. All rights reserved.

关键词： Antimony compounds

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Polycaprolactone assisted electrospinning of honey/betel with chitosan for tissue engineering

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Materials Today: Proceedings 2022年 57卷 307-315页

作者： Adhikari, Jaideep Ghosh, Manojit Das, Pratik Basak, Piyali Saha, Prosenjit School of Advanced Materials Green Energy and Sensor Systems Indian Institute of Engineering Science and Technology Shibpur West Bengal Howrah 711103 India Department of Metallurgy and Materials Engineering Indian Institute of Engineering Science and Technology Shibpur West Bengal Howrah 711103 India School of Bioscience and Engineering Jadavpur University 188 Raja S.C. Mullick Road West Bengal Kolkata 700032 India JIS University Arch Water Front Building Salt Lake City West Bengal Kolkata 700091 India

Electrospinning produces nanofibrous scaffolds, and the diameter of the nanofibers can be altered by tailoring the electrospinning parameters. Honey, betel loading on polymeric scaffolds has been used in tissue engineering applications. However, there are not many reports on electrospinning using betel extracts. In this study, electrospinning parameters for both honey/betel-loaded scaffolds have been optimized with 12% w/v polycaprolactone (PCL) solution. Further, electrospinning has been carried out by mixing the optimized honey/betel-loaded PCL solutions with a 2% w/v solution of chitosan in a 2:7 ratio. The results were also compared with the base CS/PCL scaffold. A solution of formic acid and acetone in the ratio of 4:6 was used for dissolving CS and PCL. The electrospinning parameters have been optimized for the static collector plate. Glutaraldehyde vapor crosslinking has been carried out on all the scaffolds utilizing the Schiff base reaction with an amine. Scanning electron microscopy (SEM) images revealed beadless, random oriented fibers for the optimized scaffolds. Attenuated Total Reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) has been performed on the scaffolds to identify the functional groups. The effect of glutaraldehyde crosslinking was not vivid through the FTIR study, and Differential scanning calorimetry (DSC) measurements were conducted in this regard. Enhancement in the melting point observed through DSC confirms the successful crosslinking. Contact angle measurement highlighted that honey-loaded scaffolds exhibited more hydrophilicity than betel-loaded scaffolds. Tensile strength measurement and water degradation studies have also been performed on the scaffolds. In vitro cell viability studies have been carried out with MTT assay utilizing Peripheral blood mononuclear cells (PBMCs). The scaffolds displayed excellent cell viability after 24 and 48 h. Hemocompatibility studies further identified its potential as tissue-engineered

关键词： Electrospinning

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Multiple frequency rejection using short-time fourier transform and all-pass filter-based notch filter

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Journal of Institute of Control, Robotics and systems 2021年第6期27卷 443-449页

作者： Cha, Jaehyuck Kim, Yejun Park, Chan Gook Kim, Kwanghoon Kwon, Seungbok Department of Aerospace Engineering Automation and Systems Research Institute Seoul National University Korea Republic of Institute of Advanced Aerospace Technology Seoul National University Korea Republic of Navigation/Sensor/GNSS Anti-Jamming Team LIG Nex1 Korea Republic of

This paper proposes a novel multiple frequency rejection technique based on the STFT (Short-Time Fourier Transform) and APNF (All-Pass filter-based Notch Filter). Because a non-adaptive multiple notch filter cannot track the target frequencies, an adaptive filter is often used. However, the existing adaptive notch filters cannot accurately identify the number of frequencies, which may deteriorate the filtering performance. Furthermore, a time-frequency analysis can be performed to simultaneously estimate the number of target frequencies and track them. Therefore, a novel adaptive multiple notch filtering method is developed, adopting the STFT at the front end of APNF. In particular, an interpolation scheme is adopted to compensate for the low frequency resolution of STFT. This framework exhibits a smaller amplitude response distortion for the pass-band compared to that in cascade-type multiple notch filters and can thus reject the time-varying frequencies. A MATLAB simulation is performed to verify the performance of the proposed method. The results confirm that the proposed scheme outperforms the conventional adaptive notch filter in removing chirp signals and temporary signals. © ICROS 2021.

关键词： All-pass filters

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Terahertz polarization modulator based on chiral metasurface integrated with vanadium dioxide

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Optics Letters 2025年第10期50卷 3345-3348页

作者： Luo, Li Zhou, Ling Zou, Yuxin Yang, Jiaqi Huo, Jiahui Yang, Xu Lv, Yuanyuan Bian, Jingjing Peng, Sui Liu, Bo Pan, Yudong He, Jin Li, Jie Yao, Jianquan Sichuan Province Key Laboratory of Optoelectronic Sensor Devices and Systems College of Optoelectronic Engineering Chengdu IC Valley Industrial College Chengdu University of Information Technology Chengdu610225 China Sichuan Meteorological Optoelectronic Sensor Technology and Application Engineering Research Center Chengdu University of Information Technology Chengdu610225 China Chengdu Advanced Metal Materials Industry Technology Research Institute Limited Company Chengdu610300 China School of Precision Instruments and Opto-Electronics Engineering Tianjin University Tianjin300072 China

Conventional optical polarization modulation depends on block birefringent devices, and currently there are still no commercial polarization modulation devices available for terahertz beams in free space. Metasurfaces present more opportunities for the manipulation of optical and terahertz waves, which are advantageous for highly efficient polarization modulation devices. In this paper, what we believe to be a new chiral metasurface for the polarization modulation of reflected terahertz waves is proposed that consists of vanadium dioxide (VO2) combined with metal patterns for active chiral meta-atoms. Through electric stimulation, dynamic modulation of the polarization state can be achieved. The results indicate that the metasurface shows a strong circular dichroism at an operating frequency of 0.192 THz. In the insulating state, the absorption of the right-circularly polarized (RCP) wave is significantly higher than that of the left-circularly polarized (LCP) wave. By adjusting the transition state of VO2, the chirality of the structure is reduced, enabling the reflected wave to be switched from a circularly polarized state to a linearly polarized one. The absorption and polarization of terahertz wave can also be controlled by the incident angle. This method is anticipated to promote the development of terahertz communication and imaging technologies. © 2025 Optica Publishing Group. All rights are reserved.

关键词： Circular polarization

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Remote platform for lung monitoring based on Electrical Impedance Tomography measurements 19

Remote platform for lung monitoring based on Electrical Impe...

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19th IEEE International Multi-Conference on systems, Signals and Devices, SSD 2022

作者： Hafsa, Mariem Bchir, Ons Bader, Oumaima Ben Amara, Najoua Essoukri Kanoun, Olfa Université de Sousse Ecole Nationale d' Ingénieurs de Sousse LATIS- Laboratory of Advanced Technology and Intelligent Systems Sousse4023 Tunisia Professorship of Measurement and Sensor Technology Technische Universität Chemnitz Chemnitz Germany University of Sousse National EngineeringSchool of Sousse Computer Engineering Department Sousse Tunisia

ISBN: (数字)9781665471084

ISBN: (纸本)9781665471084

Electrical Impedance Tomography (EIT) is a non-invasive, non-ionizing medical imaging method that has been on the rise in biomedical field. For lung monitoring, electrodes are attached around patient's thorax. Several boundary voltages are measured on the surface of these electrodes, which result from the injection of a small alternating current. Based on these measurements, the inner conductivity distribution of the patient's lung can be determined and used for monitoring and diagnosis. EIT can be used for extended periods of time, which makes it ideal for continuous monitoring, especially for intensive care patients. Several stationary EIT-based lung monitoring platforms have been developed for this reason. In this work, however, we propose a web and cloud-based monitoring solution that allows remote access for the doctors and medical staff. The implemented solution provides real-time, continuous monitoring as well as a visualization of extracted lung features that aid the diagnosis, © 2022 IEEE.

关键词： Electrodes

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Post-processing for Thorax Imaging based on Electrical Impedance Tomography using Deep Learning 19

Post-processing for Thorax Imaging based on Electrical Imped...

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19th IEEE International Multi-Conference on systems, Signals and Devices, SSD 2022

作者： Haddad, Hamdi Hafsa, Mariem Bader, Oumaima Ben Amara, Najoua Essoukri Kanoun, Olfa University of Sousse National Engineering School of Sousse Computer Engineering Department Sousse Tunisia Université de Sousse Ecole Nationale d'Ingénieurs de Sousse LATIS- Laboratory of Advanced Technology and Intelligent Systems Sousse4023 Tunisia Professorship of Measurement and Sensor Technology Technische Universität Chemnitz Chemnitz Germany

ISBN: (数字)9781665471084

ISBN: (纸本)9781665471084

Electrical Impedance Tomography (EIT) for lung monitoring is a non-ionizing medical imaging technique that is on the rise in biomedical engineering research in the recent decades. It reflects the inner conductivity distribution of biological tissue based on boundary voltages that appear on the electrodes, after injecting an alternating current of a certain amplitude into the human thorax. EIT, however, has a low spatial resolution and is susceptible to errors caused by electrode movement and poor contact quality, which can lead to the generation of blurry images. Post-processing imaging techniques can, in fact, be a beneficial tool for fine-tuning this issue. The focus of this work is to implement a U-NET multi-class semantic segmentation deep learning model to post-process reconstructed EIT thorax images to enhance its characteristics such as contrast, resolution... The model has achieved an overall accuracy of 72.43%. The resulting reconstructed images have reflected the physical changes during the breathing cycle, have deleted artifacts, and have made the shapes of the lungs and heart clearer. © 2022 IEEE.

关键词： Electrodes

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Electrical Impedance Tomography Image Reconstruction with apriori Knowledge for Gesture Recognition 19

Electrical Impedance Tomography Image Reconstruction with ap...

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19th IEEE International Multi-Conference on systems, Signals and Devices, SSD 2022

作者： Alasasfeh, Hayat Hafsa, Mariem Bader, Oumaima Ibbini, Mohammed Hasan, Sameer Kanoun, Olfa Jordan University of Science and Technology Biomedical Engineering Department Irbid Jordan Université de Sousse Ecole Nationale d'Ingénieurs de Sousse LATIS- Laboratory of Advanced Technology and Intelligent Systems Sousse4023 Tunisia Measurement and Sensor Technology Technische Universität Chemnitz Chemnitz Germany

ISBN: (数字)9781665471084

ISBN: (纸本)9781665471084

Electrical impedance tomography (EIT) reconstructs the conductivity images of an object based on the voltages and the currents at the surface of the object. Among the clinical applications of EIT thorax imaging, brain function monitoring and breast cancer screening. However, EIT suffers from a poor signal-to-noise ratio and spatial resolution. To improve the quality of reconstructed images and provide clear information about the structure, the paper proposes to include prior knowledge about the structure from MRI. The proposed techniques could be very promising with more work. To illustrate this technique in this paper, eight electrodes with the adjacent current pattern were employed in this research. For each gesture, forty data points are recorded. The Gauss-Newton and Back-Projection algorithms are used for image reconstruction with prior knowledge of the human forearm from MRI images. The resultant contours of the Forearm, Ulna, and Radius have been used to build the mesh. In the Gauss-Newton algorithm, the results reveal that structural information improves image quality and conductivity distribution, particularly in the region of two bones. In addition, the reconstructed images using the Gauss-Newton algorithm performed better than images reconstructed using the back-projection algorithm. © 2022 IEEE.

关键词： Image reconstruction

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Stackelberg Game for Wireless Powered and Backscattering Enabled sensor Networks

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China Communications 2024年第3期21卷 189-204页

作者： Lyu Bin Cao Yi Wang Shuai Guo Haiyan Hao Chengyao Key Laboratory of Ministry of Education in Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and TelecommunicationsNanjing 210003China Jiangsu Engineering Research Center of Novel Optical Fiber Technology and Communication Network Suzhou 215006China Guangdong-Hong Kong-Macao Joint Laboratory of Human-Machine Intelligence-Synergy Systems Shenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhen 518055China

This paper investigates a wireless powered and backscattering enabled sensor network based on the non-linear energy harvesting model, where the power beacon(PB) delivers energy signals to wireless sensors to enable their passive backscattering and active transmission to the access point(AP). We propose an efficient time scheduling scheme for network performance enhancement, based on which each sensor can always harvest energy from the PB over the entire block except its time slots allocated for passive and active information delivery. Considering the PB and wireless sensors are from two selfish service providers, we use the Stackelberg game to model the energy interaction among them. To address the non-convexity of the leader-level problem, we propose to decompose the original problem into two subproblems and solve them iteratively in an alternating manner. Specifically, the successive convex approximation, semi-definite relaxation(SDR) and variable substitution techniques are applied to find a nearoptimal solution. To evaluate the performance loss caused by the interaction between two providers, we further investigate the social welfare maximization problem. Numerical results demonstrate that compared to the benchmark schemes, the proposed scheme can achieve up to 35.4% and 38.7% utility gain for the leader and the follower, respectively.

关键词： backscatter communication energy interaction stackelberg game wireless powered sensor network

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