检索结果-南通市图书馆

A Method for Improving Power distribution Characteristics of Space Time Block Codes

在线全文

学校读者我要写书评

暂无评论

China Communications 2020年第6期17卷 223-234页

作者： Vahid Abbasi Mahrokh GShayesteh Department of Electrical Engineering Urmia UniversityUrmia 57561-15311Iran Wireless Research Lab. Elec.Eng.Dep.ACRISharif University of TechnologyTehran 11365-9363Iran

Improving Power distribution characteristics of space time block codes(STBCs),namely peak to average power ratio(PAPR),average to minimum power ratio(Ave/min),and probability of transmitting"zero"by antenna,makes easier their practical implementation.To this end,this study proposes to multiply full diversity STB C with a non-singular matrix in multiple input multiple output(MIMO)or multiple input single output(MISO)systems with linear or maximum likelihood(ML)receivers.It is proved that the obtained code achieves full diversity and the order of detection complexity does not change.The proposed method is applied to different types of STBCs.The bit error rate(BER)and Power distribution characteristics of the new codes demonstrate the superiority of the introduced method.Further,lower and upper bounds on the BER of the obtained STBCs are derived for all receivers.The proposed method provides trade-off among PAPR,spectral efficiency,energy efficiency,and BER.

关键词： full diversity linear receiver maximum likelihood peak to average power ratio Power distribution space time block codes

Research and application of wireless sensor network technology in power transmission and distribution system

在线全文

学校读者我要写书评

暂无评论

Intelligent and Converged Networks 2020年第2期1卷 199-220页

作者： Jianming Liu Ziyan Zhao Jerry Ji Miaolong Hu “Smart Grid Technology and Equipment”Expert Committee Industry Development and Promotion Center of the Ministry of Industry and Information TechnologyBeijing 100846China State Grid I&T Branch Beijing 100761China Huawei Technologies Co. Ltd.Shenzhen 518129China Wins Wireless Network Technology Co. Ltd.Jiaxing 314036China

power is an important part of the energy industry,relating to national economy and people’s livelihood,and it is of great significance to ensure the security and stability in operation of power transmission and distribution system.Based on Wireless Sensor Network technology(WSN)and combined with the monitoring and operating requirements of power transmission and distribution system,this paper puts forward an application system for monitoring,inspection,security,and interactive service of layered power transmission and distribution system.Furthermore,this paper demonstrates the system verification projects in Wuxi,Jiangsu Province and Lianxiangyuan Community in Beijing,which have been widely used nationwide.

关键词： Wireless Sensor Network(WSN) smart grid power system power transmission Power distribution monitoring system

Synthetical Efficiency-based Optimization for the Power distribution of power-split Hybrid Electric Vehicles

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2014年第1期27卷 58-68页

作者： WANG Weida HAN Lijin XIANG Changle MA Yue LIU Hui National Key Laboratory of Vehicle Transmission Beijing Institute of Technology

Now the optimization strategies for Power distribution are researched widely, and most of them are aiming to the optimal fuel economy and the driving cycle must be preknown. Thus if the actual driving condition deviates from the scheduled driving cycle, the effect of optimal results will be declined greatly. Therefore, the instantaneous optimization strategy carried out on-line is studied in this paper. The power split path and the transmission efficiency are analyzed based on a special power-split scheme and the efficiency models of the power transmitting components are established. The synthetical efficiency optimization model is established for enhancing the transmission efficiency and the fuel economy. The identification of the synthetical efficiency as the optimization objective and the constrain group are discussed emphatically. The optimization is calculated by the adaptive simulated annealing （ASA） algorithm and realized on-line by the radial basis function （RBF）-based similar models. The optimization for Power distribution of the hybrid vehicle in an actual driving condition is carried out and the road test results are presented. The test results indicate that the synthetical efficiency optimization method can enhance the transmission efficiency and the fuel economy of the power-split hybrid electric vehicle （HEV） observably. Compared to the rules-based strategy the optimization strategy is optimal and achieves the approximate global optimization solution for the Power distribution. The synthetical efficiency optimization solved by ASA algorithm can give attentions to both optimization quality and calculation efficiency, thus it has good application foreground for the Power distribution of power-split HEV.

关键词： hybrid electric vehicles power-split synthetical efficiency-based optimization Power distribution road test

Partner selection strategies in cooperative wireless networks with optimal Power distribution

在线全文

学校读者我要写书评

暂无评论

The Journal of China Universities of Posts and Telecommunications 2008年第3期15卷 47-50,58页

作者： ZHANG Qian-qian GAO Wei-dong PENG Mu-gen WANG Wen-bo Wireless Signal Processing and Network Laboratory Beijing University of Posts and Telecommunications Beijing 100876 China

There have been several results that illustrate the best performance that a network can get through cooperation of relay nodes. For practical purposes, not all nodes in the network should be involved at the same time in every transmission. Therefore, optimal partner selection protocols in cooperative wireless networks are believed to be the first important thing that should be paid attention to. This problem in our article is considered in the context of regenerative nodes and non-altruistic cooperation （no pure relay exists; all nodes have their own data to transmit）. For each transmission, the protocol must provide the user （source node） a ＇best partner＇（relay node） to cooperate with （for network simplicity and less transmission signals here, assume that each user has only one cooperative node）. A criterion is essentially needed when defining what a ＇best partner＇ is; in this article, two factors, i.e, the successful transmission probability and the transmission power, are considered. Three optimal partner selection strategies with different goals are proposed and analyzed respectively. The simulation results show that these are all supposed to be good tradeoffs between power consumption and transmission performance.

关键词： cooperative outage probability Power distribution partner selection

PMP-based equivalent fuel consumption optimization for Power distribution of power-split HEVs

在线全文

学校读者我要写书评

暂无评论

PMP-based equivalent fuel consumption optimization for power...

Attributes of Top Management Team Composition,Power distribution ＆ Diversification Strategies:Based on the Data of the Listed Chinese Manufacturing Corporations

第30届中国控制与决策会议

作者： Yanqin Wang Weida Wang Changle Xiang Xiantao Wang School of Mechanical Engineering Beijing Institute of Technology

Hybrid electric vehicle(HEV) needs appropriate control strategy and control logic to optimize the energy flow to improve the coordination of the various parts of the automotive core. This paper adopts a power split device to control the engine torque and motor torques respectively. And design two operating modes for coordinating the relationship between the motor and the engine to satisfy the demand for speed control. Based on the Power distribution background, this paper proposes PMP based equivalent fuel consumption strategy to optimize the fuel economics of HEV. This control strategy evaluates the electricity consumption of battery by oil-electricity conversion factor which converts the electricity to equivalent fuel cost by engine. Find the state space equation and optimize it with the constraints of the target as the PMP suggests. Therefore, the multi-objective cost function is proposed. The primary objective function is to minimize the equivalent fuel consumption while coordinate engine and dual motors in real time. Reduce the battery SOC fluctuation and extend the battery life. This paper analyzes several typical control strategies of HEV, and evaluates the control effect as well as fuel saving effect of control strategy. The results show that PMP based HEV control strategy can effectively reduce fuel consumption.

关键词： Hybrid electric vehicle Power distribution Fuel economy Equivalent fuel consumption

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Attributes of Top Management Team Composition,Power Distribu...

Small Lights Power distribution System Improvement of a Heavy-Duty Truck

2012 International Conference on Social Science and Education(ICSSE 2012)

作者： Tang Xuejun College of Business Yangzhou University

Based on the research sample of the listed Chinese manufacturing corporations,this essay explores the relationship between the feature of top management composition and diversification strategies as well as the moderating effect of the prestige power on the two.The research result shows that in terms of the features of top management composition,tenure and education level have negative relationships with the diversification,while there is no negative relationship between age and diversification.Considering the variables reflecting the prestige power,the moderation effect of tenure is empirically proved to exist,while that of age and education does not exist.The introduction of mediation variable of power will not only enrich the theoretical research on top management team,but also give instructions on top management team construction.

关键词： Top management team Composition feature Power distribution Diversification strategy

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Small Lights Power Distribution System Improvement of a Heav...

Non-Stationary Random Process for Large-Scale Failure and Recovery of Power distribution

FISITA 2012 World Automotive Congress--Volume 6:Vehicle Electronics

作者： Leigang Ma Fadong Yan Anhui Jianghuai Automobile Co.Ltd R＆D Centre

This paper mainly introduces a harness automobile design case,about a heavy truck small lights power system and the distribution about the improvement of the specific case.Detailed description of the small lights system load power,loop wire diameter,the status quo Power distribution structure survey,data calculation and analysis to identify the problems and then propose a variety of improvement programs,through the production process costs,resource requirements,the process of using the logic implementation,security,reliability,design concerns in five trade-off for the program to determine,by experimental verification to ensure that the program improved results.Elaborate on their understanding of the automotive wiring harness design,harness design aim for other vehicles to provide references.Specific theoretical calculations about each loop of wire did not begin due to the relationship of the papers focus.

关键词： Power distribution Wiring harness design Small lights system

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Applied Mathematics 2016年第3期7卷 233-249页

作者： Yun Wei Chuanyi Ji Floyd Galvan Stephen Couvillon George Orellana James Momoh Georgia Institute of Technology Atlanta GA USA Entergy Services Inc. New Orleans LA USA Howard University Washington DC USA

This work applies non-stationary random processes to resilience of Power distribution under severe weather. Power distribution, the edge of the energy infrastructure, is susceptible to external hazards from severe weather. Large-scale power failures often occur, resulting in millions of people without electricity for days. However, the problem of large-scale power failure, recovery and resilience has not been formulated rigorously nor studied systematically. This work studies the resilience of Power distribution from three aspects. First, we derive non-stationary random processes to model large-scale failures and recoveries. Transient Little’s Law then provides a simple approximation of the entire life cycle of failure and recovery through a queue at the network-level. Second, we define time-varying resilience based on the non-stationary model. The resilience metric characterizes the ability of Power distribution to remain operational and recover rapidly upon failures. Third, we apply the non-stationary model and the resilience metric to large-scale power failures caused by Hurricane Ike. We use the real data from the electric grid to learn time-varying model parameters and the resilience metric. Our results show non-stationary evolution of failure rates and recovery times, and how the network resilience deviates from that of normal operation during the hurricane.

关键词： Resilience Non-Stationary Random Process Power distribution Dynamic Queue Transient Little’s Law Real Data

Numerical and theoretical investigations of heat transfer characteristics in helium-xenon cooled microreactor core

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2023年第11期34卷 1-19页

作者： Tian‑Shi Wang Xiang Chai Chao‑Ran Guan Xin‑Yue Liu Jiao‑Long Deng Hui He Xiao‑Jing Liu School of Nuclear Science and Engineering Shanghai JiaoTong UniversityShanghai 200240China

Helium-xenon cooled microreactors are a vital technological solution for portable nuclear reactor power sources.To exam-ine the convective heat transfer behavior of helium-xenon gas mixtures in a core environment,numerical simulations are conducted on a cylindrical coolant channel and its surrounding solid regions.Validated numerical methods are used to determine the effect and mechanisms of power and its distribution,inlet temperature and velocity,and outlet pressure on the distribution and change trend of the axial Nusselt number.Furthermore,a theoretical framework that can describe the effect of power variation on the evolution of the thermal boundary layer is employed to formulate an axial distribution cor-relation for the Nusselt number of the coolant channel,under the assumption of a cosine distribution for the axial power.Based on the simulation results,the correlation coefficients are determined,and a semi-empirical relationship is identified under the corresponding operating conditions.The correlation derived in this study is consistent with the simulations,with an average relative error of 5.3%under the operating conditions.Finally,to improve the accuracy of the predictions near the entrance,a segmented correlation is developed by combining the Kays correlation with the aforementioned correlation.The new correlation reduces the average relative error to 2.9%and maintains satisfactory accuracy throughout the entire axial range of the channel,thereby demonstrating its applicability to turbulent heat transfer calculations for helium-xenon gas mixtures within the core environment.These findings provide valuable insights into the convective heat transfer behavior of a helium-xenon gas mixture in a core environment.

关键词： Helium-xenon gas mixture Convective heat transfer Power distribution Numerical simulation Nusselt number correlation