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Channel Cycle Time: A New Measure of Short-term Fairness

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arXiv 2023年

作者： Shen, Pengfei Shao, Yulin Pan, Haoyuan Lu, Lu Eldar, Yonina C. The University of Chinese Academy of Sciences The Key Laboratory of Space Utilization Chinese Academy of Sciences Beijing100094 China The State Key Laboratory of Internet of Things for Smart City University of Macau China The Department of Electrical and Electronic Engineering Imperial College London LondonSW7 2AZ United Kingdom The College of Computer Science and Software Engineering Shenzhen University Shenzhen China The Weizmann Institute of Science Rehovot7610001 Israel

This paper puts forth a new metric, dubbed channel cycle time (CCT), to measure the short-term fairness of communication networks. CCT characterizes the average duration between two consecutive successful transmissions of a user, during which all other users successfully accessed the channel at least once. In contrast to existing short-term fairness measures, CCT provides more comprehensive insight into the transient dynamics of communication networks, with a particular focus on users' delays and jitter. To validate the efficacy of our approach, we analytically characterize the CCTs for two classical communication protocols: slotted Aloha and CSMA/CA. The analysis demonstrates that CSMA/CA exhibits superior short-term fairness over slotted Aloha. Beyond its role as a measurement metric, CCT has broader implications as a guiding principle for the design of future communication networks by emphasizing factors like fairness, delay, and jitter in short-term behaviors. Copyright © 2023, The Authors. All rights reserved.

关键词： Jitter

Rate-Splitting Multiple Access for Quantized Multiuser MIMO Communications

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arXiv 2022年

作者： Park, Seokjun Choi, Jinseok Park, Jeonghun Shin, Wonjae Clerckx, Bruno Department of Electrical Engineering Ulsan National Institute of Science and Technology Korea Republic of The School of Electronics Engineering Kyungpook National University Korea Republic of The Department of Electrical and Computer Engineering Ajou University Suwon16499 Korea Republic of The Communications and Signal Processing Group Department of Electrical and Electronic Engineering Imperial College London LondonSW7 2AZ United Kingdom

This paper investigates the sum spectral efficiency maximization problem in downlink multiuser multiple-input multiple-output (MIMO) systems with low-resolution quantizers at an access point (AP) and users. In particular, we consider rate-splitting multiple access (RSMA) to enhance spectral efficiency by offering opportunities to boost achievable degrees of freedom. Optimizing RSMA precoders, however, is highly challenging due to the minimum rate constraint when determining the rate of the common stream. The quantization errors coupled with the precoders further make the problem more complicated and difficult to solve. In this paper, we develop a novel RSMA precoding algorithm incorporating quantization errors for maximizing the sum spectral efficiency. To this end, we first obtain an approximate spectral efficiency in a smooth function. Subsequently, we derive the first-order optimality condition in the form of the nonlinear eigenvalue problem (NEP). We propose a computationally efficient algorithm to find the principal eigenvector of the NEP as a sub-optimal solution. Simulation results validate the superior spectral efficiency of the proposed method. The key benefit of using RSMA over spatial division multiple access (SDMA) comes from the ability of the common stream to balance between the channel gain and quantization error in multiuser MIMO systems with different quantization resolutions. Copyright © 2022, The Authors. All rights reserved.

关键词： Spectrum efficiency

Gradual Resistive Switching in Electron Beam Irradiated ReS2Transistor and its Application as Electronic Synapse

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Gradual Resistive Switching in Electron Beam Irradiated ReS2...

2020 International Symposium on VLSI Technology, Systems and Applications, VLSI-TSA 2020

作者： Li, Sifan Li, Bochang Feng, Xuewei Chen, Li Li, Yesheng Huang, Li Gong, Xiao Fong, Xuanyao Ang, Kah-Wee National University of Singapore Department of Electrical and Computer Engineering 4 Engineering Drive 3 Singapore117583 Singapore Center for Advanced 2D Materials National University of Singapore 6 Science Drive 2 Singapore117546 Singapore

ISBN: (纸本)9781728142326

We demonstrate the first electron beam irradiated rhenium disulfide (ReS2) based synaptic transistor. The device exhibits gradual resistive switching (RS) ratio of 100 at a read voltage (Vd) of 1 V. The RS is attributed to sulfur vacancies motion induced by drain bias in ReS2, which modulates the Schottky barrier height (SBH) at source and drain contacts. Defect engineering and flake thickness optimization show that irradiation dosage, area and flake thickness are key parameters to improve the RS performance. In addition, the device is further utilized as an electronic synapse. Long-term plasticity mimicking the behaviors of biological synapse are implemented, showing great potential for next generation neuromorphic computing devices and systems. © 2020 IEEE.

关键词： Sulfur compounds

Interface-resolved simulations of small inertial particles in turbulent channel flow (vol 883, A54, 2020)

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JOURNAL OF FLUID MECHANICS 2020年 891卷 E2-E2页

作者： Costa, Pedro Brandt, Luca Picano, Francesco [a1]Linné FLOW Centre and SeRC (Swedish e-Science Research Centre) KTH Royal Institute of Technology - Department of Engineering Mechanics SE-100 44 Stockholm Sweden [a2]Faculty of Industrial Engineering Mechanical Engineering and Computer Science University of Iceland Hjardarhagi 2-6 107 Reykjavik Iceland [a3]Department of Industrial Engineering University of Padova Via Venezia 1 35131 Padova Italy

Thermal Comfort Model Established by Using Machine Learning Strategies Based on Physiological Parameters in Hot and Cold Environments

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Indoor Air 2024年第1期2024卷 9427822-9427822页

作者： Ho, Tseng-Fung Tsai, Hsin-Han Chuang, Chi-Chih Lee, Dasheng Huang, Xi-Wei Chen, Hsiang Cheng, Chin-Chi Kuo, Yaw-Wen Chou, Hsin-Hung Hsiao, Wei-Han Yang, Ching Hsu Li, Yung-Hui Department of Industrial Engineering and Management National Chin-Yi University of Technology No. 57 Sec. 2 Zhongshan Rd. Taiping Dist Taichung City411030 Taiwan Department of Energy and Refrigerating Air-Conditioning Engineering National Taipei University of Technology 1 Section 3 Zhongxiao East Road Taipei10608 Taiwan Department of Applied Materials and Optoelectronic Engineering National Chi Nan University Nantou54561 Taiwan Department of Electrical Engineering National Chi Nan University Nantou54561 Taiwan Department of Computer Science and Information Engineering National Chi Nan University Nantou54561 Taiwan Department and Institute of Electrical Engineering Chang Gung University No. 259 Wenhua 1st Rd. Guishan Dist Taoyuan City33302 Taiwan Department of Emergency Medicine Hsinchu Mackay Memorial Hospital No. 690 Sec. 2 Guangfu Rd. East Dist Hsinchu City300041 Taiwan AI Research Center Hon Hai Research Institute Taipei City114699 Taiwan

The air-conditioning systems have become an indispensable part of our daily life for keeping the quality of life. However, to improve the thermal comfort and reduce energy consumption is crucial to use the air conditioners effectively with rapid development of artificial intelligence technology. This study explored the correlation between the response of human physiological parameters and thermal sensation voting (TSV) to evaluate the comfort level among various cold and hot stimulations. The variations of the three physiological parameters, which were body surface temperature, skin blood flow (SBF), and sweat area on the skin surface, and TSV values were all positively correlated with the stimulation amount under the stimulation of cold wind, hot wind, and heat radiation, but the relationship was not completely linear. Among the three physiological parameters, the forehead skin temperature has the closest relationship with TSV, followed by the SBF and sweat. Among three stimulations, the cold wind stimulation causes the closest relationship between TSV and forehead temperature, followed by the radiation and hot wind stimulations. Through three different machine learning models, namely, random forest (RF) model, support vector machine (SVM) model, and neural network (NN) model, the stimulation of cold wind, hot wind, and heat radiation was applied to investigate the variation of the three physiological parameters as the input of the models. Moreover, the models were evaluated and verified by TSV. The results revealed that among the three different machine learning methods, RF had the best accuracy. The established thermal comfort models can predict the real-Time user's thermal comfort feeling, so that air-conditioning equipment's performance can be optimized to create a healthy and energy-saving comfortable environment. © 2024 Tseng-Fung Ho et al.

关键词： Thermal comfort

Dehazed Image Quality Evaluation: From Partial Discrepancy to Blind Perception

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arXiv 2022年

作者： Zhou, Wei Zhang, Ruizeng Li, Leida Liu, Hantao Chen, Huiyan Department of Electrical and Computer Engineering University of Waterloo WaterlooONN2L 3G1 Canada Beijing Institute of Technology Beijing100081 China School of Artificial Intelligence Xidian University Xi’an710071 China School of Computer Science and Informatics Cardiff University CardiffCF24 4AX United Kingdom

Image dehazing aims to restore spatial details from hazy images. There have emerged a number of image dehazing algorithms, designed to increase the visibility of those hazy images. However, much less work has been focused on evaluating the visual quality of dehazed images. In this paper, we propose a Reduced-Reference dehazed image quality evaluation approach based on Partial Discrepancy (RRPD) and then extend it to a No-Reference quality assessment metric with Blind Perception (NRBP). Specifically, inspired by the hierarchical characteristics of the human perceiving dehazed images, we introduce three groups of features: luminance discrimination, color appearance, and overall naturalness. In the proposed RRPD, the combined distance between a set of sender and receiver features is adopted to quantify the perceptually dehazed image quality. By integrating global and local channels from dehazed images, the RRPD is converted to NRBP which does not rely on any information from the references. Extensive experiment results on several dehazed image quality databases demonstrate that our proposed methods outperform state-of-the-art full-reference, reduced-reference, and no-reference quality assessment models. Furthermore, we show that the proposed dehazed image quality evaluation methods can be effectively applied to tune parameters for potential image dehazing algorithms. © 2022, CC BY.

关键词： Image quality

Applying classical control techniques to quantum systems: Entanglement versus stability margin and other limitations

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arXiv 2022年

作者： Weidner, Carrie A. Schirmer, S.G. Langbein, F.C. Jonckheere, E. The Quantum Engineering Technology Laboratories H. H. Wills Physics Laboratory Department of Electrical and Electronic Engineering University of Bristol BristolBS8 1FD United Kingdom The Faculty of Science & Engineering Swansea University SwanseaSA2 8PP United Kingdom The School of Computer Science and Informatics Cardiff University CardiffCF24 4AG United Kingdom The Department of Electrical and Computer Engineering University of Southern California Los AngelesCA90089 United States

Development of robust quantum control has been challenging and there are numerous obstacles to applying classical robust control to quantum system including bilinearity, marginal stability, state preparation errors, nonlinear figures of merit. The requirement of marginal stability, while not satisfied for closed quantum systems, can be satisfied for open quantum systems where Lindbladian behavior leads to non-unitary evolution, and allows for nonzero classical stability margins, but it remains difficult to extract physical insight when classical robust control tools are applied to these systems. We consider a straightforward example of the entanglement between two qubits dissipatively coupled to a lossy cavity and analyze it using the classical stability margin and structured perturbations. We attempt, where possible, to extract physical insight from these analyses. Our aim is to highlight where classical robust control can assist in the analysis of quantum systems and identify areas where more work needs to be done to develop specific methods for quantum robust control. Copyright © 2022, The Authors. All rights reserved.

关键词： Robust control

Covert Communication of STAR-RIS Aided NOMA Networks

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TechRxiv

TechRxiv 2022年

作者： Li, Xingwang Tian, Zhifa He, Wenjing Chen, Gaojie Gursoy, M. Cenk Mumtaz, Shahid Nallanathan, Arumugam The School of Physics and Electronic Information Engineering Henan Polytechnic University Jiaozuo China University of Surrey GuildfordGU2 7XH United Kingdom The Department of Electrical Engineering and Computer Science Syracuse University SyracuseNY13244 United States The Instituto de Telecomunicacoes Aveiro3810078 Portugal Henan Polytechnic University China The School of Electronic Engineering and Computer Science Queen Mary University of London LondonE1 4NS United Kingdom

This paper investigates covert communication in simultaneously transmitting and reflecting reconfigurable intelligent surface (STAR-RIS) assisted non-orthogonal multiple access (NOMA) systems, assuming for the sake of being more practical that the successive interference cancellation (SIC) is defective. To assess the covertness performance of the considered system, we first derive closed-form expressions for the detection error probability, the optimal detection threshold and the average minimum detection error probability of the warden, as well as the outage probability of the NOMA user pair. Then an optimization problem to maximize the effective covert rate (ECR) is proposed. According to the results of the simulation, it is possible to increase the maximum ECR of the considered system by varying the amount of components of the STAR-RIS. © 2022-12-26, CC BY.

关键词： Stars

Gate-Tunable Multi-Band van der Waals Photodetector and Polarization Sensor

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arXiv 2024年

作者： Shen, Daozhi Yang, HeeBong Patel, Tarun Rhodes, Daniel A. Timusk, Thomas Zhou, Y. Norman Kim, Na Young Tsen, Adam W. School of Mechanical Engineering Shanghai Jiao Tong University Shanghai200240 China Institute for Quantum Computing University of Waterloo WaterlooONN2L 3G1 Canada Department of Chemistry University of Waterloo WaterlooONN2L 3G1 Canada Department of Electrical and Computer Engineering University of Waterloo WaterlooONN2L 3G1 Canada Department of Physics and Astronomy University of Waterloo WaterlooONN2L 3G1 Canada Department of Materials Science and Engineering University of Wisconsin-Madison WI United States Department of Physics and Astronomy McMaster University HamiltonONL8S 4M1 Canada Centre for Advanced Materials Joining Department of Mechanical and Mechatronics Engineering University of Waterloo WaterlooONN2L 3G1 Canada Waterloo Institute for Nanotechnology University of Waterloo WaterlooONN2L 3G1 Canada

A single photodetector with tunable detection wavelengths and polarization sensitivity can potentially be harnessed for diverse optical applications ranging from imaging and sensing to telecommunications. Such a device will require the combination of multiple material systems with different structures, bandgaps, and photoelectrical responses, which is extremely difficult to engineer using traditional epitaxial films. Here, we develop a multi-functional and high-performance photosensor using all van der Waals materials. The device features a gate-tunable spectral response that is switchable between near-infrared/visible and short-/mid-wave infrared, as well as broadband operation, at room temperature. The linear polarization sensitivity in the telecommunications O-band can also be directly modulated between horizontal, vertical, and nonpolarizing modes. These effects originate from the balance of photocurrent generation in two of the active layers that can be manipulated by an electric field. The photodetector features high detectivity (>109 cmHz1/2W-1) together with fast operation speed (~ 1 MHz) and can be further exploited for dual visible and infrared imaging. Copyright © 2024, The Authors. All rights reserved.

关键词： Photodetectors