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Robust Beamforming for RIS-Assisted Wireless Communications With Discrete Phase Shifts

IEEE WIRELESS COMMUNICATIONS LETTERS 2021年第12期10卷 2619-2623页

作者： Gao, Hui Cui, Kai Huang, Chongwen Yuen, Chau Beijing Univ Posts & Telecommun BUPT Key Lab Trustworthy Distributed Comp & Serv Minist Educ Beijing 100876 Peoples R China Beijing Univ Posts & Telecommun Sch Informat & Commun Engn Beijing 100876 Peoples R China State Grid Jibei Elect Power Co Ltd Metering Ctr Beijing 100045 Peoples R China Zhejiang Univ Coll Informat Sci & Elect Engn Hangzhou 310027 Peoples R China Zhejiang Univ Zhejiang Prov Key Lab Informat Proc Commun & Netw Hangzhou 310027 Peoples R China Zhejiang Univ Int Joint Innovat Ctr Haining 314400 Peoples R China Singapore Univ Technol & Design Engn Prod Dev Pillar Singapore 119613 Singapore

In this letter, we study the robust beamforming design for the reconfigurable intelligent surface (RIS)-assisted communication systems from a multi-antenna access point (AP) to a single-antenna user under imperfect channel state information (CSI), where the RIS has only a finite number of phase shifts at each element. In particular, considering the cascaded AP-RIS-user channel estimation error, we aim to jointly optimize the transmit beamforming at the AP and discrete phase shifts of RIS to minimize the transmission power of AP, subject to a signal-to-noise ratio constraint at the user. To tackle the non-convex optimization problem, we decouple it into two subproblems and propose a novel alternative optimization framework. More specifically, the robust beamforming of AP is first obtained through S-Procedure and semidefinite relaxation. Then we recast the discrete phase shift constraint at RIS into an equivalent convex one, and propose an efficient algorithm to obtain a near optimal solution. Finally, the two subproblems are iteratively optimized to obtain joint robust beamforming. Simulation results show that the proposed scheme can approach the performance of the perfect CSI counterpart and substantially outperform traditional non-robust methods.

关键词： Array signal processing Optimization Wireless communication Signal to noise ratio Channel estimation Symmetric matrices Quantization (signal) Reconfigurable intelligent surface robust beamforming discrete phase shifts

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Prediction of three-phase product distribution and bio-oil heating value of biomass fast pyrolysis based on machine learning

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ENERGY 2021年 236卷 121401-121401页

作者： Leng, Erwei He, Ben Chen, Jingwei Liao, Gaoliang Ma, Yinjie Zhang, Feng Liu, Shuai Jiaqiang, E. Hunan Univ Coll Mech & Vehicle Engn Changsha 410082 Peoples R China Hunan Univ State Key Lab Adv Design & Mfg Vehicle Body Changsha 410082 Peoples R China State Grid Hunan Elect Power Corp Res Inst Hunan Prov Key Lab Efficient & Clean Thermal Powe Changsha 410007 Peoples R China

In this work, by mining the experimental data of fast pyrolysis of lignocellulosic biomass in bubbling fluidized bed in previous literature, regression prediction models were established for three-phase product distribution and bio-oil heating value (HHV) based on gradient boosting, random forest, support vector machine, and multilayer perceptron algorithms. Comprehensive feedstock characteristics and pyrolysis conditions were considered and compared as input features. Among the several algorithms, random forest is most suitable for the prediction of three-phase product yields and bio-oil HHV with the benefits of high accuracy and good generalization ability. Visual analysis of the model shows that pyrolysis temperature is the most critical factor affecting three-phase product distribution, while bio-oil HHV is more affected by the feedstock characteristics such as the contents of C and H. The highest yield and HHV of bio-oil is obtained at about 480 degrees C, suggesting 480 degrees C as the optimum pyrolysis temperature of fast pyrolysis of biomass in a bubbling fluidized bed. As for the feedstock characteristics, high contents of C and H and low content of O are favorable to the enhancement of bio-oil HHV, indicating the crucial importance of feedstock pretreatment such as torrefaction to the quality improvement of bio-oil. (C) 2021 Elsevier Ltd. All rights reserved.

关键词： Lignocellulosic biomass Fast pyrolysis Three-phase product yield Bio-oil heating value Machine learning

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Adversarial link deception against the link prediction in complex networks

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PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS 2021年 577卷 126074-126074页

作者： Jiang, Zhongyuan Tang, Xiaoke Zeng, Yong Li, Jinku Ma, Jianfeng Xidian Univ Sch Cyber Engn Xian 710071 Shaanxi Peoples R China Beijing Smart Chip Microelect Technol Co Ltd State Grid Key Lab Power Ind Chip Design & Anal T Beijing 102200 Peoples R China Xidian Univ Shaanxi Key Lab Network & Syst Secur Xian 710071 Shaanxi Peoples R China

Currently, the link prediction tool has been extensively used in kinds of complex networks for the use of friend, commodity, or service recommendations. However, many adversaries may maliciously or intentionally perturb a part of social links to deceive the link prediction method to suggest some unexpected missing links (referred to as targets) to users. In this work, from the attacker perspective, we propose to promote the prediction probability of given targets via adding a tiny number of new links into the network to deceive the common neighbor based link prediction method. We first define the link deception process as a similarity score maximizing problem. Secondly, we propose to use a greedy algorithm referred to as GreedyAdd to greedily adding a budget limited number of links into the network. Thirdly, considering the high time complexity of the GreedyAdd, we propose a heuristic link addition method referred to as HeuristicAdd to improve the computing efficiency. Finally, we do experiments on many real social graphs to confirm the effectiveness and efficiency of the HeuristicAdd method. The results show that the HeuristicAdd algorithm can mostly deceive the link prediction with less time consumptions than the GreedyAdd. This work considers the security problem of complex systems from a new perspective and has potential applications. (C) 2021 Elsevier B.V. All rights reserved.

关键词： Linking deception Link prediction Link addition Complex network

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Research on a Bluetooth Low Energy Warning Method 2

Research on a Bluetooth Low Energy Warning Method

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2nd International Conference on Artificial Intelligence and Computer Science, AICS 2020

作者： Long, Yan Chen, Yongli Xiao, Deyong Li, Zheng Hou, Tianpeng Zhang, Zhiwei State Grid Key Laboratory of Power Industrial Chip Design and Analysis Technology Beijing Smart-Chip Microelectronics Technology Co. Ltd. Beijing100192 China Beijing Engineering Research Center of High-Reliability Ic with Power Industrial Grade Beijing Smart-Chip Microelectronics Technology Co. Ltd. Beijing100192 China

With the development of society, intelligent terminal equipment is used more and more widely. The use of intelligent terminals to locate children's position, to ensure that children are in a safe and controllable range, is more favored by parents. But now the smart watch needs to install the mobile phone card, which depends on the mobile phone traffic to locate, and the cost is relatively high. This paper proposes a Bluetooth low energy warning method to solve this problem. The distance between the two devices is calculated by the signal strength indication value received by the intelligent terminal, and then compare the preset received signal strength indication value with the received signal strength indication value, as well as the preset distance value and the calculated distance value of the two devices. When the received signal strength indication value is less than the preset value or the distance between the devices exceeds any of the preset values, the wireless device and the intelligent terminal will send an alarm at the same time to remind the two sides wearing the intelligent terminal and the Bluetooth device that the distance between the two sides has exceeded the safety value. The Bluetooth low energy warning method proposed in this paper has the characteristics of low cost and low energy consumption. © Published under licence by IOP Publishing Ltd.

关键词： Cellular telephones

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A constant charging-current relaxation oscillator with a duty-cycled main comparator and an adaptive auxiliary comparator

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MICROELECTRONICS JOURNAL 2022年 128卷

作者： Hu, Yi Li, Zhenguo Hou, Jiali Ma, Wei Lu, Chao Xiao, Zhiming Liu, Huigang Hu, Weibo Beijing Smart Chip Microelect Technol Co Ltd State Grid Key Lab Power Ind Chip Design & Anal Te Beijing Peoples R China Nankai Univ Inst Photo Elect Thin Film Devices & Technol Tianjin Peoples R China Southern Illinois Univ Sch Elect Comp & Biomed Engn Carbondale IL 62901 USA Nankai Univ Lab Integrated Circuits & Smart Syst Shenzhen Grad Sch Shenzhen Peoples R China

A low-power constant charging-current relaxation oscillator that outputs a frequency-tunable sawtooth signal and a pulse signal is proposed and implemented in 0.5-mu m CMOS process. At the architecture level, two com-parators with 10 times difference in power consumption are proposed to break up the tight tradeoff between power consumption and oscillation performance. Most of the time, only the low-power auxiliary comparator works to save power. The high-power main comparator is controlled by the auxiliary comparator output and only works when a ramping voltage is close to a reference voltage. At the circuit level, an adaptive current control technique that makes current adversely proportional to input voltage differences is used to further reduce the power consumed in the low-power comparator. The measured clock phase noise at the offset frequency of 100 kHz is-115.07 dBc/Hz at the output frequency of 1 MHz. The measured output frequency variations are 124 ppm/degrees C over temperatures from-55 degrees C to 125 degrees C, and -0.13%-0.18% over power supplies from 3 V to 5.5 V. The frequency range from 200 kHz to 1350 kHz is achieved. The power consumption at the 1 MHz output frequency is 9.5 mu W, which is comparable with state-of-the-art designs in the literature.

关键词： Relaxation oscillator Adaptive current control Unbalanced comparator Continuous -time comparator

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RETRACTED: Adaptive Control Strategy of Multiemergency power Supply Network System Connected to New Energy (Retracted Article)

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SECURITY AND COMMUNICATION NETWORKS 2022年第1期2022卷

作者： Zhang, Wei Zhong, Ming Minfu, A. Sun, Yumei Wang, Yang Zhejiang Univ Polytech Inst Hangzhou 310015 Zhejiang Peoples R China Inner Mongolia Power Res Inst Hohhot 010020 Inner Mongolia Peoples R China Inner Mongolia Enterprise Key Lab Smart Grid Simu Hohhot 010020 Inner Mongolia Peoples R China Inner Mongolia Borelles Elect Power Engn Design C Hohhot 010010 Inner Mongolia Peoples R China

In order to improve the adaptive control effect of the multiemergency power supply networking system connected to new energy (NE), this paper studies the adaptive control strategy (ACS) of the multiemergency power supply networking system connected to NE by combining intelligent algorithms and determines the appropriate installation node of the distributed power supply according to the voltage stability index. Moreover, this paper proposes a method to optimize the distribution network feeder reorganization and distributed power configuration problems based on the fireworks algorithm to reduce the network loss and improve the voltage distribution. In addition, distribution network reorganization and distributed power configuration optimization can more effectively minimize network losses and improve voltage distribution. Through the experimental research, it can be seen that the ACS of the multiemergency power supply network system connected to NE proposed in this paper has the established effect.

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design of Quantum key Fusion Model for power Multi-terminal

Design of Quantum Key Fusion Model for Power Multi-terminal

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International Conference on Information Systems and Computer Aided Education (ICISCAE)

作者： Shaoxian Xia Zheng Wang Zhanbin Hou Hongshu Ye Binbin Xue Shouzhi Wang Xuecheng Zhang Kewen Yang State Grid Key Laboratory of Power Industrial Chip Design and Analysis Technology Beijing Smart-Chip Microelectronics Technology Co. Ltd. Beijing China

ISBN: (数字)9781728183046

ISBN: (纸本)9781728194608

With the construction of State grid informatization, professional data such as operation inspection, marketing, and regulation have gradually shifted from offline to online. In recent years, cyberspace security incidents have occurred frequently, and national and group cybersecurity threats have emerged. As the next-generation communication system, quantum security has to satisfy the security requirements. Also, it is especially important to build the fusion application of energy network quantum private communication technology and conventional network, and to form a safe and reliable quantum-level communication technology solution suitable for the power grid. In this paper, from the perspective of the multi-terminal quantum key application, combined with a mature electricity consumption information collection system, a handheld meter reading solution based on quantum private communication technology is proposed to effectively integrate the two and achieve technological upgrading. First, from the technical theory and application fields, the current situation of quantum private communication technology and its feasibility of combining with classical facilities are introduced and analyzed. Then, the hardware security module and handheld meter reading terminal equipment are taken as typical examples to design and realize quantum key shared storage, business security process application model; finally, based on the overall environment of quantum key distribution, the architecture design of multi-terminal quantum key application verification is implemented to verify the quantum key business application process.

关键词： Quantum computing Communications technology Meter reading Reliability Computer security Secure storage Business

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Tailoring skyrmion motion dynamics via magnetoelectric coupling: Toward highly energy-efficient and reliable non-volatile memory applications

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JOURNAL OF APPLIED PHYSICS 2022年第8期132卷 084902-084902页

作者： Zhao, Xuefeng Wang, Di Zhang, Hao Liu, Long Lin, Huai Wang, Ziwei Zhang, Xueying Xie, Changqing Lin, Weinan Gao, Nan Pan, Cheng Xing, Guozhong Chinese Acad Sci Inst Microelect Key Lab Microelect Devices & Integrated Technol Beijing 100029 Peoples R China Univ Sci & Technol China Sch Microelect Hefei 230026 Peoples R China Univ Chinese Acad Sci Chinese Acad Sci Beijing 100049 Peoples R China Beihang Univ Fert Beijing Inst Sch Integrated Circuit Sci & Engn MIIT Key Lab Spintron Beijing 100191 Peoples R China Xiamen Univ Dept Phys Xiamen 361005 Peoples R China Beijing Smart Chip Microelect Technol Co Ltd State Grid Key Lab Power Ind Chip Design & Anal Te Beijing 102200 Peoples R China

Owing to the intriguing physical properties and significant spintronic applications, magnetic skyrmions have recently drawn intensive attention. Particularly, the skyrmion-based non-volatile memory (Sky-NVM) devices promise to be spintronic building blocks with high efficiency. However, tailoring Sky-NVM to achieve an energy-efficient and reliable operation in a synthetic, CMOS compatible, and magnetic-field-free integration is a challenging issue. Here, we report a new type of compact Sky-NVM with tailored skyrmion motion dynamics via in-plane strain gradient engineering. The skyrmion motion is merely driven by an in-plane electric field utilizing the magnetoelectric coupling effect, and the programmable switching is realized by gate biasing the potential barrier height via a voltage-controlled magnetic anisotropy. The proposed device is CMOS process compatible, and the comprehensive micromagnetic simulation results demonstrate that by applying a 0.3 V in plane voltage combined with -0.17 V gate voltage, its write latency and the energy consumption reach 5.85 ns and 4.77 aJ/bit, respectively, superior to the state-of-the-art counterparts. Our work paves a new path toward ultra-low-power spintronic memory devices. Published under an exclusive license by AIP Publishing.

关键词： Magnetic anisotropy

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design of short-circuit protection circuit for half bridge topology switching power supply 3

Design of short-circuit protection circuit for half bridge t...

引用

3rd IEEE Advanced Information Management, Communicates, Electronic and Automation Control Conference, IMCEC 2019

作者： Jian, Wang Tao, Li Xiu-Li, Yu State Grid Key Laboratory of Power Industrial Chip Design and Analysis Technology Beijing Smart-Chip Microelectronics Technology Co. Ltd. Beijing China

ISBN: (纸本)9781728105130

Half bridge switching power supply has problems such as poor capacitive starting capacity and easy malfunction of short-circuit protection circuit. Then a new type of short-circuit protection circuit for switching power supply is designed. The circuit is for sampling and protection based on half bridge partial voltage capacitance ripple characteristics. It has the advantages of rapid fault protection adjustable trigger time and recovery time. It shows that the circuit scheme has a good protective effect on the power converter in various load environments, and it has reached desired effect, according to the simulation results and the circuit application results. © 2019 IEEE.

关键词： power converters

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Phase tracking algorithm of IEEE 802.15.4g MR-OFDM with frequency offset

Phase tracking algorithm of IEEE 802.15.4g MR-OFDM with freq...

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2019 International Conference on Electronic Engineering and Informatics, EEI 2019

作者： Tang, Xiaoke Liu, Jichao Zhao, Dongyan Wang, Yubo Zhao, Yahong State Grid Key Laboratory of Power Industrial Chip Design and Analysis Technology Beijing Smart-Chip Microelectronics Technology Co. Ltd. Beijing China

ISBN: (纸本)9781728140766

IEEE 802.15.4g Standard specifies multi-rate and multi-regional orthogonal frequency division multiplexing (MR-OFDM) physical layer, which supports principally outdoor, low-data-rate, wireless, smart metering utility network (SUN). The inter-channel interference (ICI) results in subcarrier frequency sampling offset and phase shift for signal on MR-OFDM. In this paper, phase tracking algorithms which estimate and compensate the offset on symbols are studied. A basic phase tracking method is presented that the phase rotation of reception signal can be recognized by using the data on the pilot tones. Furthermore, in order to mitigation the influence of noise, an average-based algorithm is proposed as a modified solution. In contrast with the basic method, the average-based algorithm enhances the reliability of phase tracking. Simulations of algorithms are assessed, which are in accordance with theoretical analysis. © 2019 IEEE.

关键词： Orthogonal frequency division multiplexing

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