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China Communications 2024年第1期21卷 148-162页

作者： Yizhe Zhao Yanliang Wu Jie Hu Kun Yang School of Information and Communication Engineering University of Electronic Science and Technology of ChinaChengdu 611731China

Integrated data and energy transfer(IDET)enables the electromagnetic waves to transmit wireless energy at the same time of data delivery for lowpower *** this paper,an energy harvesting modulation(EHM)assisted multi-user IDET system is studied,where all the received signals at the users are exploited for energy harvesting without the degradation of wireless data transfer(WDT)*** joint IDET performance is then analysed theoretically by conceiving a practical time-dependent wireless *** the aid of the AO based algorithm,the average effective data rate among users are maximized by ensuring the BER and the wireless energy transfer(WET)*** results validate and evaluate the IDET performance of the EHM assisted system,which also demonstrates that the optimal number of user clusters and IDET time slots should be allocated,in order to improve the WET and WDT performance.

关键词： energy harvesting modulation(EHM) integrated data and energy transfer(IDET) performance analysis wireless data transfer(WDT) wireless energy transfer(WET)

Optimization and performance analysis of Intelligent Video AI Dynamic

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Journal of Electronic Research and Application 2024年第3期8卷 142-147页

作者： Yu Xing Xidian University Xi’an 710000China

In today’s information age,video data,as an important carrier of information,is growing explosively in terms of production *** quick and accurate extraction of useful information from massive video data has become a focus of research in the field of computer *** dynamic recognition technology has become one of the key technologies to address this issue due to its powerful data processing capabilities and intelligent recognition *** on this,this paper first elaborates on the development of intelligent video AI dynamic recognition technology,then proposes several optimization strategies for intelligent video AI dynamic recognition technology,and finally analyzes the performance of intelligent video AI dynamic recognition technology for reference.

关键词： Intelligent video AI dynamic recognition Technology optimization performance analysis

Python Server Page performance analysis and Modeling

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Communications and Network 2024年第1期16卷 1-30页

作者： Razafindraibe Marolahy Alix Randrianomenjanahary Lala Ferdinand Rafamantanantsoa Fontaine Mahatody Thomas F. Angelo Raherinirina University of Fianarantsoa Fianarantsoa Madagascar

Today, in the field of computer networks, new services have been developed on the Internet or intranets, including the mail server, database management, sounds, videos and the web server itself Apache. The number of solutions for this server is therefore growing continuously, these services are becoming more and more complex and expensive, without being able to fulfill the needs of the users. The absence of benchmarks for websites with dynamic content is the major obstacle to research in this area. These users place high demands on the speed of access to information on the Internet. This is why the performance of the web server is critically important. Several factors influence performance, such as server execution speed, network saturation on the internet or intranet, increased response time, and throughputs. By measuring these factors, we propose a performance evaluation strategy for servers that allows us to determine the actual performance of different servers in terms of user satisfaction. Furthermore, we identified performance characteristics such as throughput, resource utilization, and response time of a system through measurement and modeling by simulation. Finally, we present a simple queue model of an Apache web server, which reasonably represents the behavior of a saturated web server using the Simulink model in Matlab (Matrix Laboratory) and also incorporates sporadic incoming traffic. We obtain server performance metrics such as average response time and throughput through simulations. Compared to other models, our model is conceptually straightforward. The model has been validated through measurements and simulations during the tests that we conducted.

关键词： performance analysis Queue performance Model Web Server Internet World Wide Web Web Server performance

performance analysis of Hybrid Distribution in Human-Centric Multimedia Networking

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Chinese Journal of Electronics 2016年第4期25卷 761-767页

作者： HU Yuxiang DONG Fang LAN Julong National Digital Switching System Engineering and Technological Research Center

With the booming of Human-centric multimedia networking(HMN),there are rising amount of human-made multimedia that needs to distribute to consumers with higher speed and *** distribution of Client/Server(C/S) and Peer-to-Peer(P2P) have been successfully deployed on the Internet and the practical benefits have been widely reported,while its theoretical performance remains unknown for mass data delivery *** paper presents an analytical and experimental study on the performance of accelerating large-scale hybrid distribution over the *** particular,this paper focuses on the user behavior in HMN and establishes a user behavior model based on the Kermack-McK endrick model in *** expressions of average delay in HMN are then derived based on C/S,P2 P and hybrid distribution,*** simulation shows how to design and deploy a hybrid distribution system of HMN that helps to bridge the gap between system ultilization and quality of service,which provides direct guidance for practical system design.

关键词： Hybrid distribution Peer-to-peer Client/server Behaviour model performance analysis

performance analysis of full-duplex densely distributed MIMO with wireless backhaul

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Science China(Information Sciences) 2023年第6期66卷 186-203页

作者： Ziqian WAN Qijun PAN Jiamin LI Pengcheng ZHU Dongming WANG National Mobile Communications Research Laboratory Southeast University Purple Mountain Laboratories

In this paper, the spectral efficiency of a full-duplex(FD)densely distributed multi-input multioutput(MIMO)system with wireless backhaul is considered. In-band full-duplex(IBFD)backhauling, in which the backhaul and access transmissions take place on the same spectrum, is exploited for wireless backhauling to enable an efficient spectrum reuse. However, the severe cross-tier interference and crosslink interference reduce the gains of IBFD backhauling. To evaluate the achievable spectral efficiency with imperfect channel state information(CSI), we propose a two-phase channel estimation scheme to estimate the CSI for two wireless links, and the scheme estimates an effective interference CSI between access points(APs)based on beamforming training to perform interference cancelation at APs. Given the estimated CSI,the closed-form expressions of the uplink and downlink achievable rates with maximum ratio transmission beamforming and maximum ratio combining receivers, respectively, are derived with Gamma *** results verify the accuracy of the derived closed-form expressions and the effectiveness of the twophase channel estimation scheme for interference cancelation. Moreover, compared with half-duplex densely distributed MIMO systems, FD systems with interference cancelation have a better performance.

关键词： full-duplex wireless backhaul performance analysis beamforming training interference cancelation

performance analysis and application on Ti-6Al-4V of micro-forging system

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Chinese Journal of Aeronautics 2021年第6期34卷 188-198页

作者： Yufei GUI Qi LIU Yun ZHU Sulin CHEN Bin SHEN School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240China

Micro-forging(MF)is a novel surface modification technology which is capable of smoothening and strengthening the workpiece surface *** on analysis of the mechanism and energy conversion of micro-forging process,an electromagnetically driven microforging system is *** further grasp the kinetic characteristic of the equipment,a simulation model is established and its accuracy is *** the help of simulation and experimental results,we propose an input voltage optimization method,which drives the micro-forging head moving in a uniform and stable *** this study,the influence of MF on surface integrity of Ti-6 Al-4 V(TC4)is firstly *** results show that MF treatment reduces surface roughness(Ra)and increases micro-hardness by 48%and 11.8%at most,***,a compressive stress layer with an amplitude of-1000 MPa and a depth of 0.8 mm is *** study analyzes the performance and reveals the potential of micro-forging technology,which lays a solid foundation for expanding its application in TC4 surface modification.

关键词： Input voltage Micro-forging system performance analysis Surface integrity Titanium alloy

performance analysis and Flexible Control of a Novel Ball Double-screw Hydraulic Robot Knee Joint

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Journal of Bionic Engineering 2023年第5期20卷 2147-2163页

作者： Jie Shao Yongming Bian Meng Yang Guangjun Liu School of Mechanical Engineering Tongji UniversityShanghai201804China State Key Laboratory of Fluid Power and Mechatronic Systems Zhejiang UniversityHangzhou310027China Department of Control Science and Engineering Tongji UniversityShanghai201804China National Engineering Technology Research Center for Prefabrication Construction in Civil Engineering Tongji UniversityShanghai200092China

Focusing on the ball double-screw hydraulic knee joint as the research object,this paper analyzes the load driving performance of the hydraulic knee *** the posture data of the human body such as walking,squatting and landing buffer as initial learning objects,motion features are *** simplifying the trajectories of different motion actions into key feature control points and flexible trajectory fitting,the trajectory of joint actions is *** method can realize the adaptability of the hydraulic robot knee joint in different movements,and take the flexible action as the optimization goal under the condition of ensuring the movement performance,so as to reduce the damage to the knee joint caused by the foot impact in *** simulation model was built by Adams and Matlab to complete the performance analysis and motion optimization experiment of the knee *** simulation results show that the foot impact force of the experimental model decreases gradually through ***,the method is applied to the hydraulic joint experimental prototype to prove its load capacity and flexible motion control performance.

关键词： Bionic robot Ball double-screw hydraulic joint Robot knee joint performance analysis Humanoid motion control Flexible control

performance analysis and design of self-air-cooling reciprocating compressor’s cooling system

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Science China(Technological Sciences) 2020年第12期63卷 2631-2639页

作者： LIU YongGuang GAO XiaoHui CHENG NanNan School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China

The cooling system,as an important part of high-pressure compressor,has always been a key technical bottleneck for its miniaturization. A new type self-air-cooling system is first proposed for the reciprocating compressor through ingenious structural design without any auxiliary equipment. The transient model of cooling system is established,which regards the cooling passage as a chamber with compressibility and heat exchange considering the linear and local flow resistance. The design principle is achieved by studying the working process and key parameters characteristics,which provides the theoretical foundation for the structural design. The experimental results show that the self-air-cooling system can quickly lower the temperature of the cylinder compared with natural cooling,which has considerable theoretical significance and practical value for the miniature high pressure compressor.

关键词： self-air-cooling reciprocating compressor design performance analysis

performance analysis and Prediction of Double-Server Polling System Based on BP Neural Network

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Chinese Journal of Electronics 2020年第6期29卷 1046-1053页

作者： YANG Zhijun MAO Lei GAN Jianhou DING Hongwei School of Information Science and Technology Yunnan University Educational Instruments and Facilities Service Center Educational Department of Yunnan Province Key Laboratory of Education Informalization for Nationalities of Ministry of Education Yunnan Normal University

To solve the poor performance of the single-server polling system in high traffic and the complex analysis of the multi-server polling system,a synchronous double-server polling system is proposed,and its performance is analyzed using a Backpropagation(BP) neural network prediction *** data are processed and analyzed,and a three-layer multiinput single-output BP network model is constructed to predict the performance of the polling system under different arrival rates of information *** the prediction stage,first,the data are processed and the average queue length under different information arrival rates is used to form a ***,a multiinput single-output BP neural network is constructed for *** results show that the algorithm can accurately predict the performance of the double-server polling system,thereby facilitating research regarding polling systems.

关键词： backpropagation neural nets queueing theory three-layer multiinput single-output BP network model prediction stage information arrival rates multiinput single-output BP neural network performance analysis single-server polling system complex analysis multiserver polling system synchronous double-server polling system backpropagation neural network prediction algorithm information packets Polling system BP neural network Prediction Average queue length Long-short term memory (LSTM)

performance analysis of rate-adaptive cooperative MAC based on wireless local area networks

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The Journal of China Universities of Posts and Telecommunications 2009年第5期16卷 78-85页

作者： ZHANG Yang , XU Hong-kun, CHANG Yong-yu, YANG Da-cheng, WANG Ya-feng School of Information and Communication Engineering, Beijing University of Posts and Telecommunications, Beijing 100876, China School of Information and Communication Engineering Beijing University of Posts and Telecommunications Beijing 100876 China

Bi-dimensional Markov chain model based on cooperative medium access control （MAC） of wireless local area networks （WLAN） is considered to reflect system performance accurately. Two basic factors that affect the analysis results are station retry limits and non-saturated transmit probability. A uniform solution considering both factors is proposed. To prove the theoretical analysis, a cooperative MAC （CoopMAC） topology is established and the simulation model is enhanced by changing the cooperative table to the nodes＇ memory with more information added. Meanwhile, the three-way handshake scheme is modified and a handshake threshold is set based on the packet size. Simulation results show the performance analytical model is accurate, and the rate-adaptive cooperative MAC protocol significantly improves the network performance in terms of non-saturated system throughput and delay.

关键词： performance analysis cooperative MAC bi-dimensional Markov Chain non-saturated transmit station retry limit