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efficiency analysis and reconfiguration control method of small satellite remote sensing formation constellation

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Efficiency analysis and reconfiguration control method of sm...

analysis on Operational Safety and efficiency of FAO System in Urban Rail Transit

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作者： FENG Xiao-hui BAI Bao-cun State Key Laboratory of Laser Propulsion and Application Space Engineering University DFH SATELLITE CO.LTD

The effectiveness and reconfiguration analysis of Leo large-scale remote sensing satellite constellation is of great significance to satellite constellation system design and system *** article first analyzed the performance of the latest remote sensing satellite constellation through comprehensive index evaluation function. Then the feature of on-orbit service failure was analyzed according to the service availability of life prediction model. The residual properties of constellation in different failure modes was also introduced and the optimization strategy for the rest of the constellation to reconfiguration was optimized. Finally, the reconfiguration path was reconstructed by the optimal control method and LQR control strategy was used to the simulation, which can assess the overall performance of the constellation in the process of damage and reconstruction and the rationality of the reconfiguration scheme.

关键词： efficiency analysis reconfiguration control constellation simulation remote sensing satellite

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Computers, Materials & Continua 2023年第12期77卷 3677-3696页

作者： Kaige Guo Jin Zhou Xiaoming Zhang Di Sun Zishuo Wang Lixian Zhao Department of Traffic Engineering College of Urban Rail Transit and LogisticsBeijing Union UniversityBeijingChina

This paper discusses two urgent problems that need to be solved in fully automatic operation(FAO)for urban rail *** first is the analysis of safety in FAO,while another is the analysis of efficiency in ***,this paper establishes an operational safety evaluation index system from the perspective of operation for the unique or typical risk sources of the FAO system,and uses the analytic hierarchy process(AHP)to evaluate the indicators,analyzes various factors that affect the safe operation of FAO,and provides safety management recommendations for FAO lines operation to maintain the FAO system ***,taking the Yanfang Line as an example,this paper uses OpenTrack software to analyze the efficiency of FAO operation,and conducts simulation calculations for key links such as the mainline tracking interval,train entry and exit,and return limit *** fault impact surface of the FAO trains is simulated and discussed to verify whether FAO can meet the long-term operation requirements of Yanfang ***,this paper compares the simulation data of FAO on the Yanfang Line with manual operation(MO)to verify the advantages of FAO and guide the engineering construction of subsequent fully automated driving lines.

关键词： Fully automatic operation safety analysis efficiency analysis OpenTrack simulation

A Design of an SMTP Email Server

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Journal of Electronic Research and Application 2024年第4期8卷 41-47页

作者： Liheng Hu School of Cybersecurity Beijing University of Posts and TelecommunicationsBeijing 100876China

This study developed a mail server program using Socket API and *** program uses the Hypertext Transfer Protocol(HTTP)to receive emails from browser clients and forward them to actual email service providers via the Simple Mail Transfer Protocol(SMTP).As a web server,it handles Transmission Control Protocol(TCP)connection requests from browsers,receives HTTP commands and email data,and temporarily stores the emails in a ***,as an SMTP client,the program establishes a TCP connection with the actual mail server,sends SMTP commands,and transmits the previously saved *** addition,we also analyzed security issues and the efficiency and availability of this server,providing insights into the design of SMTP mail servers.

关键词： Mail server Socket API HTTP protocol SMTP protocol Security analysis efficiency analysis

Evaluation of Transmission Losses of Various Battery Electric Vehicles

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Automotive Innovation 2022年第4期5卷 388-399页

作者： Johannes Hengst Matthias Werra Ferit KüÇükay Institute of Automotive Engineering TU BraunschweigBraunschweigGermany

Transmission losses in battery electric vehicles have compared to internal combustion engine powertrains a larger share in the total energy consumption and play therefore a major ***,the power flows not only during propulsion through the transmissions,but also during recuperation,whereby efficiency improvements have a double *** investigation of transmission losses of electric vehicles thus plays a major *** this paper,three simulation models of the Institute of Automotive Engineering(the lossmap-based simulation model,the modular simulation model,and the 3D simulation model)are *** lossmap-based simulation model calculates transmission losses for electric and hybrid transmissions,where three spur gear transmission concepts for battery electric vehicles are *** transmission concepts include a single-speed transmission as a reference and two two-speed ***,the transmission lossmaps are integrated into the modular simulation model(backward simulation)and in the 3D simulation model(forward simulation),which improves the simulation *** modular simulation model calculates the optimal operation of the transmission concepts and the 3D simulation model represents the more realistic behavior of the transmission *** different transmission concepts are investigated in Worldwide Harmonized Light Vehicle Test Cycle and evaluated in terms of transmission losses as well as the total energy *** map-based simulation model allows the transmission losses to be broken down into the individual component losses,thus allowing transmission concepts to be examined and evaluated in terms of their efficiency in the early development stage to develop optimum powertrains for electric axle *** considering transmission losses in detail with a high degree of accuracy,less efficient concepts can be eliminated at an early development *** a result,only relevant concepts are built as prototypes,which reduce

关键词： Battery electric vehicle(BEV) Transmission losses efficiency analysis WLTC Backward simulation Forward simulation Energy consumption

Circuit model based design and analysis for a four-structure-switchable wireless power transfer system

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Science China(Technological Sciences) 2015年第3期58卷 534-544页

作者： FANG XueLin LIU Hao LI GuiYang SHAO Qi LI HongYi State Key Laboratory of Robotics Shenyang Institute of Automation Chinese Academy of Sciences University of Chinese Academy of Sciences

The four-coil wireless power transfer(WPT)technology can effectively improve the transfer *** high efficiency,however,cannot be obtained along the whole transfer distance due to the phenomenon of frequency splitting in the over coupled *** at this limitation,this paper presents a switchable WPT system to improve the overall efficiency by changing the number of working *** switching conditions for the designed system are determined based on the analysis of the transfer efficiencies of four structures,which is deduced through modeling the equivalent *** simulation results well comply with the experimental results and both of them indicate that the switchable system can greatly improve the overall transfer efficiency along the whole transfer *** overall efficiency of the experimental system can reach above 70%at9.97 MHz without additional complexity,which is higher than any single structure system.

关键词： magnetic resonance coupling efficiency analysis structures switched wireless power transfer

Numerical research on airfoil transition delay by alternative current dielectric barrier discharge actuation

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Chinese Journal of Aeronautics 2021年第2期34卷 441-453页

作者： Bei LIU Hua LIANG Zhonghua HAN Yinghong LI Fei LIU Jiangbo CHI Zhiwen DING Science and Technology on Plasma Dynamics Laboratory Air Force Engineering UniversityXian 710038China Institute of Aerodynamic and Multidisciplinary Design Optimization National Key Laboratory of Science and Technology on Aerodynamic Design and ResearchSchool of AeronauticsNorthwestern Poly technical UniversityXi'an 710072China

A Dielectric Barrier Discharge(DBD) plasma actuator can create a body force which locally accelerates the base flow leading to an attenuation of broadband disturbance to delay the transition. In this study, numerical simulation on an NLF0416 airfoil is conducted to investigate transition delay and drag reduction by a DBD plasma actuator. To simulate plasma’s effect more accurately, boundary-layer data is acquired from Reynolds Averaged Navier Stocks(RANS) equations instead of laminar boundary layer equations, although RANS equations need a much finer boundary-layer grid, and the linear stability analysis method is used to analyze the boundary layer and get the transition point. In this study, the influences of different actuation intensities and positions are investigated, and results show that if the actuation intensity is stronger and the actuation position is closer to the base transition point, more drag reduction can be obtained. However, the efficiency of plasma transition delay is really low. For example, when the actuation voltage is 16 k V,the actuation frequency is 1 k Hz, and the main Mach number is 0.1, the saved power due to drag reduction is about 5.09 W, but the power consumed is about 32.61 W, and the efficiency is just15.6%.

关键词： Dielectric Barrier Discharge(DBD) efficiency analysis Linear stability analysis Plasma flow control Plasma transition delay

Measuring the social performance of forest management

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Journal of Forestry Research 2021年第5期32卷 1803-1818页

作者： Timo Pukkala University of Eastern Finland P.O.Box 11180101 JoensuuFinland

Forests produce several types of benefits to both forest landowners and *** social benefit of private forestry is equal to private benefit plus positive externalities minus negative *** study developed alternative metrics for the evaluation of the social benefit of forest *** management was assessed in terms of five criteria:economic,socio-cultural,environmental and ecological performance and the resilience of the forest *** criterion was described with three numerical *** performance indices were calculated from the indicator values using methods developed for multi-criteria decision *** was concluded that indices based on the multiplicative Cobb-Douglas utility function might be the most recommendable when forestry should produce a balanced combination of different ecosystem *** the indices were used to compare alternative silvicultural systems in terms of their social performance,continuous cover management was ranked better than even-aged *** performance of even-aged management improved when it aimed at increasing the share of mixed stands and broadleaf *** net present value(NPV) with a 1 % discount rate led to better social performance than maximizing NPV with a 4% discount rate.

关键词： efficiency analysis Acceptability Sustainable forestry Performance index Utility function Multi-criteria analysis Continuous cover forestry Evenaged forestry Resilience

Comprehensive Survey and Critical Evaluation of the Performance of State-of-the-art LED Drivers for Lighting Systems

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Chinese Journal of Electrical Engineering 2021年第2期7卷 21-36页

作者： Fernando Bento Antonio J.Marques Cardoso CISE-Electromechatronic Systems Research Centre University of Beira InteriorCovilhã6201-001Portugal

The adoption of light-emitting diodes(LEDs)for lighting applications is becoming increasingly relevant as this recent technology is *** the recent uptake of LED lighting technologies for distinctive end-uses,the research community has also committed to the development of an ever-increasing range of power electronic converters that are suitable for yielding maximum quality lighting,high efficiency,and long *** one of the most recent and promising technologies of the moment,it is vital to fully understand the performance and merits of each state-of-the-art LED lighting ***,this paper compiles essential information about a broad range of state-of-the-art LED lighting systems,aiming to compare their performances in terms of *** on the comparative analysis,the main merits and drawbacks of each LED lighting system architecture are ***,a detailed evaluation of the performance of a particular LED lighting system and the corresponding control strategy is developed,thereby enabling a clear view of the evolution of the performance of the system as a function of parameters like supply voltage and number of driver channels.

关键词： efficiency analysis LED lighting AC-DC converters DC-DC converters

TBM Construction Process Simulation and Performance Optimization

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Transactions of Tianjin University 2010年第3期16卷 194-202页

作者：刘东海周云晴焦凯 School of Civil Engineering Tianjin University

Long tunnel excavation with tunnel boring ily affected by uncertainties and needs to be adjusted machine （TBM） is a complex and stochastic process. It is eas- according to specific geological conditions in different tunnel sections, which makes the construction scheduling and management difficult. Based on the rock mass classification, this paper estimates the penetration rate. Using the rate, a cyclic network simulation （CYCLONE） model of TBM boring system is established, and the advance rates under different geological conditions are determined. Then, the impact of different cutter head thrust, which is chosen in reasonable range according to previous experiences, on pro- ject schedule is analyzed. Moreover, the simulation model of mucking system is built to determine the number of muck trains and rail intersections reasonably, regarding the efficiency of muck loading and material transporting. Based on the interaction and interrelation between TBM boring system and mucking system, the combined CY- CLONE model for the entire tunneling process is established. Then reasonable construction schedule, the utilization rate of working resources, and the probability of project completion are obtained through the model programming. At last, a project application shows the feasibility of the presented method.

关键词： tunnel boring machine (TBM) construction simulation schedule efficiency analysis optimization