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A Visualized Design Method for 360° Wideband Continuously Tunable Phase Shifters With Low Phase Error and Simple Control Scheme

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IEEE Transactions on Microwave Theory and Techniques 2025年

作者： Lyu, Yun-Peng Jiang, Qian Zhu, Lei Liu, Qianwen Huang, Feng Cheng, Qiang Nanjing University of Posts and Telecommunications College of Telecommunication and Information Engineering Nanjing 210003 China Southeast University State Key Laboratory of Millimeter Waves Nanjing 210096 China University of Macau Faculty of Science and Technology Department of Electrical and Computer Engineering Macao Nanjing University of Posts and Telecommunications College of Electronic and Optical Engineering Nanjing 210003 China

This article introduces a new design method for 360° continuously tunable phase shifters (PSs) with wide bandwidth (BW) and low phase error. In this design, the concept of the phase slope circle, combined with a geometric method, is proposed to address the key issue of large phase error in reflective-type PS (RTPS). This method can directly evaluate the phase shift range (PSR) and phase deviation of the continuously tunable PS with respect to the varactor capacitance C_v. When its trajectory falls on the equal-phase-slope circle, low phase error can be achieved and vice versa. It offers explicit guidance and well-defined design criteria for realizing wideband RTPSs with large PSR and low phase error. We systematically analyze the existing reflective loads, including the capacitive, single resonated, and multiple resonated loads, and explicitly illustrate their limitations. To attain a large PSR and low phase error, new reflective loads consisting of mixed lumped and distributed resonators are proposed, and the underlying working mechanism of low phase error characteristic has been elucidated. We also put forward a quantitative and efficient design method accompanied by formulas. To verify the design concept, two prototypes of the proposed 180° and 360° wideband continuously tunable PSs were designed, fabricated, and measured. Both the simulation and measured results are in good agreement. To the best of our knowledge, as of now, this is the widest 360° continuously tunable PS featuring low phase error and the simplest control scheme in low-cost printed circuit board (PCB) technology. Merely two dc control lines are required to achieve an uninterrupted phase shift adjustment spanning from 0° to 360° across a wide operating BW of 50%. It also has the advantages of compact size, good impedance matching, and low insertion loss (IL). © 1963-2012 IEEE.

关键词： Continuous tunability low phase error phase shifter (PS) phase slope circle visualized design method wideband

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In Situ Graft‑on Fibrous Composites and Nanostructure Interlocking Facilitate Highly Stable Wearable Sensors for SIDS Prevention

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advanced Fiber Materials 2024年第3期6卷 825-840页

作者： Kaifeng Chen Weitao Wang Zhihao Ye Yabo Dong Linpu Wan Zijian Zhang Cheng Lin Liwu Liu Jinsong Leng Xinyu Wang Wei Yang Shaoxing Qu Zongrong Wang State Key Laboratory of Silicon and Advanced Semiconductor Materials and School of Materials Science and Engineering Zhejiang UniversityHangzhou 310027People’s Republic of China Institute of Thermal Science and Technology Shandong UniversityJinan 250061People’s Republic of China School of Computer Science and Technology Zhejiang UniversityHangzhou 310027People’s Republic of China Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province and School of Aeronautics and Astronautics Zhejiang UniversityHangzhou 310027People’s Republic of China Department of Astronautical Science and Mechanics Harbin Institute of Technology(HIT)Harbin 150001People’s Republic of China Center for Composite Materials and Structures Harbin Institute of Technology(HIT)Harbin 150080People’s Republic of China

High-performance and reliable wearable devices for healthcare are in high demand for the health monitoring of infants,ensuring that life-threatening events can be addressed ***,the continuous monitoring of infant respiration for preventing sudden infant death syndrome(SIDS)is proposed using high-performance flexible piezoresistive sensors(FPS).The thorny challenges associated with FPS,including the signal drift and poor repeatability,are progressively improved via the employment of high-Tg matrix,the strengthening of in situ graft-on conducting polyaniline layer byβ-cyclodextrin(β-CD),and the nanostructure interlocking between the piezoresistive layer and *** sensor presents high linear sensitivity(30.7 kPa^(−1)),outstanding recoverability(low hysteresis up to 1.98%FS),static stability(4.00%signal drift after 24 h at 2.4 kPa)and dynamic stability(1.92%decay of signal intensity after 50,000 cycles).A wireless infant respiration monitoring system is *** patterns and the real-time respiration rate are displayed on the *** are implemented when abnormal status such as bradypnea and tachypnea is detected.

关键词： Wearable devices Flexible pressure sensor Respiration monitoring Inclusion complex In situ graft-on composite

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Pixelation with concentration-encoded effective photons for molecular optical sectioning microscopy

arXiv

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arXiv 2023年

作者： Wang, Geng Iyer, Rishyashring R. Sorrells, Janet E. Aksamitiene, Edita Chaney, Eric J. Renteria, Carlos A. Park, Jaena Shi, Jindou Sun, Yi Boppart, Stephen A. Tu, Haohua Beckman Institute for Advanced Science and Technology University of Illinois at Urbana-Champaign UrbanaIL61801 United States Department of Electrical and Computer Engineering University of Illinois at Urbana-Champaign UrbanaIL61801 United States Department of Bioengineering University of Illinois at Urbana-Champaign UrbanaIL61801 United States

Quality control in molecular optical sectioning microscopy is indispensable for transforming acquired digital images from qualitative descriptions to quantitative data. Although numerous tools, metrics, and phantoms have been developed, accurate quantitative comparisons of data from different microscopy systems with diverse acquisition conditions remains a challenge. Here, we develop a simple tool based on an absolute measurement of bulk fluorophore solutions with related Poisson photon statistics, to overcome this obstacle. Demonstrated in a prototypical multiphoton microscope, our tool unifies the unit of pixelated measurement to enable objective comparison of imaging performance across different modalities, microscopes, components/settings, and molecular targets. The application of this tool in live specimens identifies an attractive methodology for quantitative imaging, which rapidly acquires low signal-to-noise frames with either gentle illumination or low-concentration fluorescence labeling. © 2023, CC BY.

关键词： Metadata

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Reconfigurable topological modes in acoustic non-Hermitian crystals

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Physical Review B 2023年第20期107卷 L201108-L201108页

作者： Haiyan Fan He Gao Tuo Liu Shuowei An Xianghong Kong Guoqiang Xu Jie Zhu Cheng-Wei Qiu Zhongqing Su Department of Mechanical Engineering The Hong Kong Polytechnic University Hung Hom Kowloon Hong Kong SAR China Department of Electrical and Computer Engineering National University of Singapore Singapore 116083 Singapore Key Laboratory of Noise and Vibration Research Institute of Acoustics Chinese Academy of Sciences Beijing 100190 China Institute of Acoustics School of Physics Science and Engineering Tongji University Shanghai 200092 China Shanghai Research Institute for Intelligent Autonomous Systems Tongji University Shanghai 201210 China

Non-Hermiticity, usually represented in the context of gain and loss, gives rise to many exotic topological phenomena and offers more opportunities to steering topological functions. In modern acoustics, it has been widely perceived that the topological mode will be altered if topological phase changes. Our work shows otherwise in non-Hermitian acoustic crystals. We experimentally demonstrate an acoustic quadrupole topological insulator, whose topological corner, edge, and bulk modes could be arbitrarily engineered at any desired positions with its topological phase maintained. These non-Hermiticity-controlled topological modes bestow a bulk structure with unique features beyond the classical bulky state, offering a reconfigurable and versatile approach to manipulating topological phenomena. This non-Hermitian scheme can be readily generalized to other topological systems in various dimensions, such as the three-dimensional photonic/phononic lattices, which offer advanced and externally controllable recipes for manipulating topological phenomena.

关键词： Acoustic metamaterials Metamaterials Topological defects Non-Hermitean systems

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Position: social choice should guide AI alignment in dealing with diverse human feedback 24

Position: social choice should guide AI alignment in dealing...

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Proceedings of the 41st International Conference on Machine Learning

作者： Vincent Conitzer Rachel Freedman Jobst Heitzig Wesley H. Holliday Bob M. Jacobs Nathan Lambert Milan Mossé Eric Pacuit Stuart Russell Hailey Schoelkopf Emanuel Tewolde William S. Zwicker Foundations of Cooperative AI Lab Computer Science Department Carnegie Mellon University Pittsburgh and Institute for Ethics in AI University of Oxford Oxford UK Center for Human-Compatible AI Department of Electrical Engineering and Computer Sciences University of California Berkeley Potsdam Institute for Climate Impact Research Potsdam Brandenburg Germany Department of Philosophy University of California Berkeley Department of Philosophy and Moral Sciences Ghent University Ghent Begium Allen Institute for AI Berkeley California Department of Philosophy University of Maryland College Park EleutherAI Foundations of Cooperative AI Lab Computer Science Department Carnegie Mellon University Pittsburgh Department of Mathematics Union College Schenectady and Murat Sertel Center for Advanced Economic Studies Istanbul Bilgi University Istanbul Turkey

Foundation models such as GPT-4 are fine-tuned to avoid unsafe or otherwise problematic behavior, such as helping to commit crimes or producing racist text. One approach to fine-tuning, called reinforcement learning from human feedback, learns from humans' expressed preferences over multiple outputs. Another approach is constitutional AI, in which the input from humans is a list of high-level principles. But how do we deal with potentially diverging input from humans? How can we aggregate the input into consistent data about "collective" preferences or otherwise use it to make collective choices about model behavior? In this paper, we argue that the field of social choice is well positioned to address these questions, and we discuss ways forward for this agenda, drawing on discussions in a recent workshop on Social Choice for AI Ethics and Safety held in Berkeley, CA, USA in December 2023.

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NM-LUD: A NLOS Mitigation Method with Low-cost UWB Devices for Indoor Positioning

NM-LUD: A NLOS Mitigation Method with Low-cost UWB Devices f...

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International Conference on computers, Communications, and Systems (ICCCS)

作者： Tong Wu Han Li Bo Gao Ke Xiong Pingyi Fan Khaled Ben Letaief Engineering Research Center of Network Management Technology for High Speed Railway of Ministry of Education School of Computer and Information Technology Beijing Jiaotong University Beijing China Collaborative Innovation Center of Railway Traffic Safety Beijing Jiaotong University Beijing China National Engineering Research Center of Advanced Network Technologies Beijing Jiaotong University Beijing China Department of Electronic Engineering Tsinghua University Beijing China Department of Electrical and Computer Engineering Hong Kong University of Science and Technology Hong Kong

Ultra-wideband (UWB) is a popular technology for indoor positioning. However, non-line-of-sight (NLOS) propagation caused by human occlusion dramatically affects the accuracy of UWB-based indoor positioning. Most of the existing works focused on mitigating NLOS errors in the scenarios with building structure occlusion, but the NLOS mitigation under human occlusion has not been well addressed. To this end, this paper aims to mitigate the NLOS impact of human occlusion, and then proposes a method of NLOS mitigation to reduce NLOS ranging errors under human occlusion with low-cost UWB devices (i.e., NM-LUD). It takes a set of signal features extracted from low-cost devices as input, calculates their weights and mitigates the ranging error based on the features' weights. Experiment results on the two data sets collected by LinkTrack S and UML1 UWB devices show that the method reduces ranging error from 0.9009 m to 0.1435 m (about by 84.07%) and from 0.7466 m to 0.0792 m (about by 89.39%) respectively, which greatly mitigates the influence of NLOS caused by human occlusion.

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Synthetic oversampling based decision support framework to solve class imbalance problem in smoking cessation program

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International Journal of Applied science and engineering 2020年第3期17卷 223-235页

作者： Davagdorj, Khishigsuren Lee, Jong Seol Park, Kwang Ho Van Huy, Pham Ryu, Keun Ho Database and Bioinformatics Laboratory College of Electrical and Computer Engineering Chungbuk National University Cheongju South Korea Faculty of Information Technology Ton Duc Thang University Ho Chi Minh City Viet Nam Department of Computer Science College of Electrical and Computer Engineering Chungbuk National University Cheongju South Korea

Smoking is one of the significant avoidable risk factors for premature death. Most smokers make multiple quit attempts during their lifetime but smoking dependence is not easy and many people eventually failed quit attempts. Predicting the likelihood of success in smoking cessation program is necessary for public health. In recent years, a few numbers of decision support systems have been developed for dealing with smoking cessation based on machine learning techniques. However, the class imbalance problem is increasingly recognized as serious in real-world applications. Therefore, this paper presents a synthetic minority over-sampling technique (SMOTE) based decision support framework in order to predict the success of smoking cessation program using Korea National Health and Nutrition Examination Survey (KNHANES) dataset. We carried out experiments as follows: I) the unnecessary instances and variables have been eliminated, II) then we employed three variations of SMOTE, III) also the prediction models have been constructed. Finally, compare the prediction models to obtain the best model. Our experimental results showed that SMOTE improved the prediction performance of machine learning classifiers among evaluation metrics. Moreover, SMOTE regular based Random Forest (RF) and Naïve Bayes (NB) classifiers were determined the best prediction models in real-world smoking cessation dataset. Consequently, our decision support framework can interpret the important risk factors of smoking cessation using multivariate regression analysis. Copyright: The Author(s). This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted distribution provided the original author and source are cited.

关键词： Class imbalance Machine learning classifiers Risk factor analysis Smoking cessation Synthetic minority oversampling

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MIMO-aided Irregular Repetition Schemes for Mission Critical Communications

MIMO-aided Irregular Repetition Schemes for Mission Critical...

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IEEE Conference on Vehicular Technology (VTC)

作者： Linlin Zhao Shaodan Ma Guanghua Yang Xuefen Chi Wanting Yang Department of Communications Engineering Jilin University Changchun China Yibin Institute of Jilin University Yibin China Department of Electrical and Computer Engineering University of Macau Macau SAR China State Key Laboratory of Internet of Things for Smart City University of Macau Macau SAR China School of Intelligent Systems Science and Engineering Jinan University Zhuhai China

Mission critical communications require ultra-high reliability guarantees. It is a natural idea to combine massive multiple-input multiple-output (MIMO) and repetition transmission to further improve the reliability. In this paper, we combine the irregular repetition scheme with the massive MIMO with grant-free access. By introducing random transmission patterns for replicas, the collision problem of grant-free access is mitigated. Considering finite block-length coding, as well as sporadic and periodic arrivals of mission critical traffic, the reliability is thoroughly analyzed and derived in closed form. The theoretical analysis is finally verified through computer simulations. It is observed that the reliability of periodic traffic is superior to the sporadic one in large MIMO systems.

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Positioning Using Visible Light Communications: A Perspective Arcs Approach

arXiv

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arXiv 2022年

作者： Zhu, Zhiyu Guo, Caili Bao, Rongzhen Chen, Mingzhe Saad, Walid Yang, Yang The Beijing Key Laboratory of Network System Architecture and Convergence School of Information and Communication Engineering Beijing University of Posts and Telecommunications Beijing100876 China The Department of Electrical Engineering Princeton University Princeton NJ08544 United States Beijing Laboratory of Advanced Information Networks School of Information and Communication Engineering Beijing University of Posts and Telecommunications Beijing100876 China The Wireless@VT Bradley Department of Electrical and Computer Engineering Virginia Tech BlacksburgVA24060 United States

Visible light positioning (VLP) is an accurate indoor positioning technology that uses luminaires as transmitters. In particular, circular luminaires are a common source type for VLP, that are typically treated only as point sources for positioning, while ignoring their geometry characteristics. In this paper, the arc feature of the circular luminaire and the coordinate information obtained via visible light communication (VLC) are jointly used for positioning, and a novel perspective arcs approach is proposed for VLC-enabled indoor positioning. The proposed approach does not rely on any inertial measurement unit and has no tilted angle limitaion at the user. First, a VLC assisted perspective circle and arc algorithm (V-PCA) is proposed for a scenario in which a complete luminaire and an incomplete one can be captured by the user. Based on plane and solid geometry theory, the relationship between the luminaire and the user is exploited to estimate the orientation and the coordinate of the luminaire in the camera coordinate system. Then, the pose and location of the user in the world coordinate system are obtained by single-view geometry theory. Considering the cases in which parts of VLC links are blocked, an anti-occlusion VLC assisted perspective arcs algorithm (OA-V-PA) is proposed. In OA-V-PA, an approximation method is developed to estimate the projection of the luminaire's center on the image and, then, to calculate the pose and location of the user. Simulation results show that the proposed indoor positioning algorithm can achieve a 90th percentile positioning accuracy of around 10 cm. Moreover, an experimental prototype is implemented to verify the feasibility. In the established prototype, a fused image processing method is proposed to simultaneously obtain the VLC information and the geometric information. Experimental results in the established prototype show that the average positioning accuracy is less than 5 cm for different tilted angles of the user.

关键词： Visible light communication

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Energy Harvesting Aware Client Selection for Over-the-Air Federated Learning

Energy Harvesting Aware Client Selection for Over-the-Air Fe...

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GLOBECOM 2022 - 2022 IEEE Global Communications Conference

作者： Caijuan Chen Yi-Han Chiang Hai Lin John C.S. Lui Yusheng Ji The Graduate University for Advanced Studies (SOKENDAI) and National Institute of Informatics (NII) Tokyo Japan Department of Electrical and Electronic Systems Engineering Osaka Metropolitan University Osaka Japan Department of Computer Science Engineering The Chinese University of Hong Kong Hong Kong

ISBN: (纸本)9781665435413

Federated learning (FL) has been widely regarded as a promising distributed machine learning technology that utilizes on-device computation while protecting clients' data privacy. To adapt FL to wireless networks, the over-the-air (OTA) computation, which employs the superposition nature of wireless waveforms, can prevent excessive consumption of the communication resources. However, energy harvesting technology can overcome the energy limitation of clients to realize durable computation. Despite the existing works devoted to OTA FL from various aspects, they mostly neglect jointly performing client selection and energy management for energy harvesting devices. In this paper, we investigate the combined problem of client selection and energy management for OTA FL and formulate it as a nonlinear integer programming (NIP) problem to minimize the optimality gap. To solve the NIP problem, we propose a client selection scheme that jointly considers channel state information, residual battery capacities, and dataset size. Our simulation results show that the proposed solution outperforms other comparison schemes within various parameter settings.

关键词： Performance evaluation Integer programming Federated learning Wireless networks Simulation Energy harvesting Global communication

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