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arXiv 2020年

作者： Xie, Weiqiang Chang, Lin Shu, Haowen Norman, Justin C. Peters, Jon D. Wang, Xingjun Bowers, John E. Department of Electrical and Computer Engineering University of California Santa BarbaraCA93106 United States State Key Laboratory of Advanced Optical Communications System and Networks Department of Electronics School of Electronics Engineering and Computer Science Peking University Beijing100871 China Institute for Energy Efficiency University of California Santa BarbaraCA93106 United States

Aluminum gallium arsenide (AlGaAs) and related III-V semiconductors have excellent optoelectronic properties. They also possess strong material nonlinearity as well as high refractive indices. In view of these properties, AlGaAs is a promising candidate for integrated photonics, including both linear and nonlinear devices, passive and active devices, and associated applications. For integrated photonics low propagation loss is essential, particularly in nonlinear applications. However, achieving low-loss and high-confinement AlGaAs photonic integrated circuits poses a challenge. Here we show an effective reduction of surface-roughness-induced scattering loss in fully etched high-confinement AlGaAs-on-insulator nanowaveguides, by using a heterogeneous wafer-bonding approach and optimizing fabrication techniques. We demonstrate ultrahigh-quality AlGaAs microring resonators and realize quality factors up to 3.52×106 and finesses as high as 1.4×104. We also show ultra-efficient frequency comb generations in those resonators and achieve record-low threshold powers on the order of ~20 µW and ~120 µW for the resonators with 1 THz and 90 GHz free-spectral ranges, respectively. Our result paves the way for the implementation of AlGaAs as a novel integrated material platform specifically for nonlinear photonics, and opens a new window for chip-based efficiency-demanding practical applications. Copyright © 2020, The Authors. All rights reserved.

关键词： III-V semiconductors

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Fractional-order biological system: chaos, multistability and coexisting attractors

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The European Physical Journal Special Topics 2021年第5期231卷 1061-1070页

作者： Debbouche, Nadjette Ouannas, Adel Momani, Shaher Cafagna, Donato Pham, Viet-Thanh Laboratory of Dynamical System and Control University of Larbi Ben M’hidi Oum El Bouaghi Algeria Department of Mathematics and Computer Sciences Larbi Ben M’hidi University Oum El Bouaghi Algeria Nonlinear Dynamics Research Center (NDRC) College of Humanities and Sciences Ajman University Ajman UAE Department of Mathematics Faculty of Science University of Jordan Amman Jordan Department of Innovation Engineering University of Salento Lecce Italy Nonlinear Systems and Applications Faculty of Electrical and Electronics Engineering Ton Duc Thang University Ho Chi Minh City Vietnam

In this paper, the nonlinear dynamics of the biological system modeled by the fractional incommensurate order Van der Pol equations are investigated. The stability of the proposed fractional non-autonomous system is analyzed by varying both the fractional order derivative and system parameters. Moreover, very interesting phenomena such as symmetry, multi-stability and coexistence of attractors are discovered in the considered biological system. Numerical simulations are performed by considering the Caputo fractional derivative and results are reported by means of bifurcation diagrams, computation of the largest Lyapunov exponent, phase portraits in 2D and 3D projections.

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Inter-area coordination approach for metro train regulation under localized bi-directional power supply shortage during peak periods

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computers & Industrial engineering 2025年 207卷

作者： Xuekai Wang Andrea D’Ariano Shuai Su Tao Tang Boyi Su Maode Yan School of Electronics and Control Engineering Chang’an University Xi’an 700054 China State Key Laboratory of Advanced Rail Autonomous Operation Beijing Jiaotong University Beijing 100044 China Frontiers Science Center for Smart High-speed Railway System Beijing Jiaotong University Beijing 100044 China Department of Civil Computer Science and Aeronautical Technologies Engineering Roma Tre University Rome 00154 Italy

Faults in the traction power supply system of metro lines frequently cause Localized Bi-directional Power Supply Shortage (LBPSS) during peak periods, significantly restricting the traction power available to trains in the under-supplied area, and have knock-on impacts on train operations in other regions. To mitigate the impacts of LBPSS on the entire line, this paper proposes an inter-area coordination approach for the train regulation problem, dividing the global problem into three sequential sub-problems. In the first stage, a cooperative control approach optimizes the control strategies in the under-supplied area, restoring the balance between power supply and demand within the power supply capacity constraints. Building on these results, the second stage reschedules the train timetable in the well-supplied areas using multiple dispatching measures. Since synchronization of entry and exit times between different regions may not be fully achieved in the first two stages, the third stage fine tures hard-to-synchronize entry/exit times, and adjusts control strategies in the under-supplied area via feedback adjustment. To address the unique challenges of each sub-problem, this paper adopts the specific algorithms: Independent Deep Q-Networks (IDQN) for cooperative control, the GUROBI solver for timetable rescheduling, and Adaptive Large-scale Neighborhood Search (ALNS) for fine-tuning synchronization. Notably, for complex constraints associated with the feedback adjustment problem, an improved ALNS algorithm is introduced, which incorporating a constraint operator to enhance convergence speed and solution quality through heuristic rules. Finally, numerical experiments based on the Beijing Metro Yizhuang Line validate the effectiveness of the proposed approach. Results indicate that the solution quality improves by up to 20.0% and 2.8% compared to two previous train regulation approaches: the conservative approach based on maximum traction power and the two-stage ap

关键词： Adaptive large-scale neighborhood search Distributed train dispatching Localized bi-directional power supply shortage Metro system Train regulation

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Angle estimation for terahertz ultra-massive MIMO-based space-to-air communications

arXiv

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arXiv 2021年

作者： Liao, Anwen Gao, Zhen Yang, Yang Nguyen, Ha H. Wang, Hua Yin, Hao School of Information and Electronics Beijing Institute of Technology Beijing100081 China Advanced Research Institute of Multidisciplinary Science Beijing Institute of Technology Beijing100081 China School of Information and Communication Engineering BUPT Beijing100876 China Department of Electrical and Computer Engineering University of Saskatchewan SaskatoonSKS7N 5A9 Canada Institute of China Electronic System Engineering Corporation Beijing100141 China

This paper investigates terahertz ultra-massive (UM)-MIMO-based angle estimation for space-to-air communications, which can solve the performance degradation problem caused by the dual delay-beam squint effects of terahertz UM-MIMO channels. Specifically, we first design a grouping true-time delay unit module that can significantly mitigate the impact of delay-beam squint effects to establish the space-to-air THz link. Based on the subarray selection scheme, the UM hybrid array can be equivalently considered as a low-dimensional fully-digital array, and then the fine estimates of azimuth/elevation angles at both UAVs and satellite can be separately acquired using the proposed prior-aided iterative angle estimation algorithm. The simulation results that close to Cramér-Rao lower bounds verify the effectiveness of our solution. Copyright © 2021, The Authors. All rights reserved.

关键词： Unmanned aerial vehicles (UAV)

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Special Processors Simulation for Forming and Digital Processing of Error-Correcting Codes in computer systems

Special Processors Simulation for Forming and Digital Proces...

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International Conference on Modern Problems of Radio engineering, Telecommunications and computer Science

作者： Taras Grynchyshyn Volodymyr Hryha Artur Voronych Mykhaylo Ilko Department of Programming and Information Technologies National Transport University Nadvirna UKRAINE Department of Computer Engineering and Electronics Vasyl Stefanyk Precarpathian National University Ivano-Frankivsk UKRAINE Department of Computer System and Networks Ivano-Frankivsk National Technical University of Oil and Gas Ivano-Frankivsk UKRAINE

ISBN: (数字)9781728155661

ISBN: (纸本)9781728155678

The methods of digital and pulse signal modulation in modern computer systems of data transmission are analysed. Process of forming non-redundant coding that use the errors detection and correction in the Galois basis are offered. Structures of special processors for forming signal correcting codes are built. Working algorithms for proposed coding methods are developed and their software implementation are offered. Circuit design of Galois code sequence generator is implemented. Work simulation and synthesis on FPGA of Xilinx are performed.

关键词： digital signal processing chips encoding error correction codes error detection codes field programmable gate arrays Galois fields logic design microprocessor chips Error correction codes Field programmable gate arrays digital signal processing chips error detection codes computer systems Galois fields Microprocessor chips Logic design coding Forming Galois sequence generator Digital signal processing

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Three-step one-way model in terahertz biomedical detection

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PhotoniX 2021年第1期2卷 279-296页

作者： Yan Peng Jieli Huang Jie Luo Zhangfan Yang Liping Wang Xu Wu Xiaofei Zang Chen Yu Min Gu Qing Hu Xicheng Zhang Yiming Zhu Songlin Zhuang Shanghai Key Lab of Modern Optical System Terahertz Technology Innovation Research InstituteUniversity of Shanghai for Science and Technology516 Jungong RoadShanghai 200093China Department of Nephrology Tongji HospitalTongji University School of MedicineShanghai 200065China Laboratory of Artificial-Intelligence Nanophotonics University of Shanghai for Science and TechnologyShanghai 200093P.R.China. Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics Massachusetts Institute of TechnologyCambridgeMA 02139USA. The Institute of Optics University of RochesterRochesterNew York 14627USA.

Terahertz technology has broad application prospects in biomedical ***, the mixed characteristics of actual samples make the terahertz spectrumcomplex and difficult to distinguish, and there is no practical terahertz detectionmethod for clinical medicine. Here, we propose a three-step one-way terahertzmodel, presenting a detailed flow analysis of terahertz technology in the biomedicaldetection of renal fibrosis as an example: 1) biomarker determination: screeningdisease biomarkers and establishing the terahertz spectrum and concentrationgradient;2) mixture interference removal: clearing the interfering signals in the mixturefor the biomarker in the animal model and evaluating and retaining the effectivecharacteristic peaks;and 3) individual difference removal: excluding individualinterference differences and confirming the final effective terahertz parameters in thehuman sample. The root mean square error of our model is three orders ofmagnitude lower than that of the gold standard, with profound implications for therapid, accurate and early detection of diseases.

关键词： Terahertz spectroscopy Renal fibrosis Biomedical detection Biomarker Mixture interference Individual difference

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An unsupervised hourly weather status pattern recognition and blending fitting model for PV system fault detection

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Applied Energy 2022年 319卷

作者： Jiaqi Qu Zheng Qian Yan Pei Lu Wei Hamidreza Zareipour Qiang Sun School of Instrumentation and Optoelectronic Engineering Beihang University Beijing China School of Electronics and Information Engineering Beihang University Beijing China The Department of Electrical and Computer Engineering University of Calgary Calgary Canada State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing China

Detecting PV system faults in a timely fashion is important to ensure the safe operation of equipment and reduce their impact on the economy of the PV systems. It is necessary to further improve the time-sensitive performance evaluation of the system. However, the hourly weather scenario segmentations are seldom considered during the hour-level online monitoring process. Therefore, a hybrid method based on unsupervised hourly weather status pattern recognition and blending fitting model is proposed for hourly fault detection to improve the performance evaluation of PV systems. The proposed solution includes three parts, firstly, in the data preprocessing stage, the measured power with the errors and noise under normal operation situation caused by the environment changes is corrected by monthly linear fitting. Secondly, an unsupervised hourly weather status pattern recognition method is constructed using the measured radiation data, including unsupervised clustering and the Multiclass-GBDT-LR classification process. Finally, after eliminating the anomalies and errors, the blending fitting model of the hourly sub-weather status is established. Through the analysis of power plants in Australia and China, the proposed solutions are validated and evaluated to be superior to existing data-driven solutions in terms of fitting accuracy, detection validity, and response time. Numerical results of case studies indicate that the developed methodology under sub-weather has improved the detection accuracy up to 97.71% and 99.29% compared to benchmark models.

关键词： Photovoltaic systems performance Hourly fault detection Unsupervised hourly weather status pattern recognition Blending fitting model

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Analysis of smart city environment by artificial intelligent techniques

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AIP Conference Proceedings 2023年第1期2831卷

作者： Sujay Mugaloremutt Jayadeva A. K. Gnanasekar Prashant Sunagar N. Harshith Sahil Sanjeev Salvi Ashok Kumar Department of Health System Management Studies JSS Academy of Higher Education & Research (Faculty of Management Studies) Mysuru-570015 India Department of Electronics & Communication Engineering Rajalakshmi Institute of Technology Chembarambakkam Chennai Tamil Nadu-600124 India Department of Civil Engineering M.S. Ramaiah Institute of Technology MSR Nagar Bengaluru Karnataka-560054 India Department of Civil Engineering Pimpri Chinchwad College of Engineering and Research Ravet Pune Maharashtra-412101 India Department of Computer Science Banasthali Vidyapith Banasthali Rajasthan-304022 India

The expectation of artificial intelligence is happened to realize in such a way that it essentially and most peculiarly supports the sustainable enhancement of fore coming smart environment surrounding the cities. The contribution towards the different developing fields of artificial intelligence have been made in determining the transformation towards traditional cities with conventional facilities into fully built smart environmental cities. The knowledge of producing better standards of living by rebuilding technology into daily activities of human is the primary requirements of the smart city emergence with esteemed technologies. In this proposed study, the concepts are enlightened towards few enhanced and developed technologies and identification of solutions to different problems that has been faced by people due to absence of digital environment. It illustrates certain problems that has been related to the smart city infrastructure, security, public safety, which lends suitable solutions for the denoted problems. It not only creates the emphasis on the technique of artificial intelligence but also on the Internet of Things (IoT) applications, pattern recognitions, deep and machine learning, analytics of big data and infrastructures associated with cloud computing in establishing the development as a completely equipped smart city.

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Robust boundary extraction of great lakes by blocking Active Contour Model using Chinese GF-3 SAR data: A case study of Danjiangkou reservoir, China

Robust boundary extraction of great lakes by blocking Active...

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IET International Radar Conference 2018, IRC 2018

作者： Niu, Shilin Li, Ning Guo, Zhengwei Wang, Robert Guo, Yuexiu Wu, Lin Zhao, Jianhui School of Computer and Information Engineering Henan University Kaifeng475004 China Space Microwave Remote Sensing System Department Institute of Electronics Chinese Academy of Sciences Beijing100190 China

Chinese Gaofen-3 (GF-3) satellite is a spaceborne multi-polarisation synthetic aperture radar (SAR) mission in C-band and it can be applied in the multiple fields. GF-3 can achieve accurate water boundary extraction based on its high-resolution SAR image products. This paper will study GF-3's capability to extract water boundary. Danjiangkou reservoir, the largest artificial freshwater lake in Asia and water source of Chinese South-to-North Water Diversion Project, is selected as the study region. A novel segmentation method is proposed which consists of two parts: the first part is rough segmentation to get the initial boundary;the second part is fine segmentation to get the final water boundary. Experimental results show that GF-3 has good performance in water boundary exaction by virtue of this novel method. © 2019 Institution of engineering and Technology. All rights reserved.

关键词： Synthetic aperture radar

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On the Road to 6G: Visions, Requirements, Key Technologies and Testbeds

arXiv

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arXiv 2023年

作者： Wang, Cheng-Xiang You, Xiaohu Gao, Xiqi Zhu, Xiuming Li, Zixin Zhang, Chuan Wang, Haiming Huang, Yongming Chen, Yunfei Haas, Harald Thompson, John S. Larsson, Erik G. Di Renzo, Marco Tong, Wen Zhu, Peiying Shen, Xuemin Poor, H. Vincent Hanzo, Lajos The National Mobile Communications Research Laboratory School of Information Science and Engineering Southeast University Nanjing210096 China The Purple Mountain Laboratories Nanjing211111 China The School of Information Science and Engineering The State Key Laboratory of Millimeter Waves Southeast University Nanjing210096 China The Pervasive Communication Research Center Purple Mountain Laboratories Nanjing211111 China The School of Engineering The University of Warwick CoventryCV4 7AL United Kingdom The LiFi Research and Development Center Department of Electronic and Electrical Engineering University of Strathclyde GlasgowG1 1XQ United Kingdom The Institute for Digital Communications School of Engineering University of Edinburgh EdinburghEH9 3JL United Kingdom Linköping University Linköping581 83 Sweden Université Paris-Saclay CNRS CentraleSupélec Laboratoire des Signaux et Systèmes 3 Rue Joliot-Curie Gif-sur-Yvette91192 France The Wireless Advanced System and Competency Centre HUAWEI Technologies Co. Ltd. OttawaONK2K 3J1 Canada HUAWEI Technologies Canada Co. Ltd. OttawaONK2K 3J1 Canada The Department of Electrical and Computer Engineering University of Waterloo WaterlooONN2L 3G1 Canada The Department of Electrical and Computer Engineering Princeton University PrincetonNJ08544 United States The School of Electronics and Computer Science University of Southampton SouthamptonSO17 1BJ United Kingdom

Fifth generation (5G) mobile communication systems have entered the stage of commercial development, providing users with new services and improved user experiences as well as offering a host of novel opportunities to various industries. However, 5G still faces many challenges. To address these challenges, international industrial, academic, and standards organizations have commenced research on sixth generation (6G) wireless communication systems. A series of white papers and survey papers have been published, which aim to define 6G in terms of requirements, application scenarios, key technologies, etc. Although ITU-R has been working on the 6G vision and it is expected to reach a consensus on what 6G will be by mid-2023, the related global discussions are still wide open and the existing literature has identified numerous open issues. This paper first provides a comprehensive portrayal of the 6G vision, technical requirements, and application scenarios, covering the current common understanding of 6G. Then, a critical appraisal of the 6G network architecture and key technologies is presented. Furthermore, existing testbeds and advanced 6G verification platforms are detailed for the first time. In addition, future research directions and open challenges are identified for stimulating the on-going global debate. Finally, lessons learned to date concerning 6G networks are discussed. © 2023, CC BY.

关键词： Network architecture

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