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作者： Lee, Jae-Bok Zou, Jun Li, Mo Chang, Sughun Electrical Environment Research Center Korea Electrotechnology Research Institute Changwon Korea Republic of State Key Lab. of Control and Simulation of Power Systems and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing China

Purpose - A fast algorithm is proposed to calculate the lightning electromagnetic field over a perfectly conducting earth surface. Design/methodology/approach - The channel base current is approximated by a number of sub-domain quadratic functions using the proposed adaptive sampling technique, and the derivative and integral of the channel base current with respect to time can be analytically expressed. With the help of these approximations, the ideal electromagnetic field of the lightning channel can be evaluated along the lightning channel with respect to the height. Findings - The computational time can be greatly reduced using the proposed approach to evaluate the electromagnetic field of a lightning channel in the time domain. Originality/value - The adaptive sampling technique is a general-purposed approach, which can be potentially used in other applications to fit a function with the minimal number of intervals. © Emerald Group Publishing Limited.

关键词： Electromagnetic fields

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Effect of mechanical aeration on nitrogen and microbial activity in sediment-water interface from urban lake

Effect of mechanical aeration on nitrogen and microbial acti...

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2012 Asian Pacific Conference on Energy, Environment and Sustainable Development, APEESD 2012

作者： Chen, Jianjun Lu, Shaoyong Liao, Zaiyi Ai, Shichao Huang, Minsheng College of hydraulic and Environment Enginneering China three gorges university YiChang 443002 China Engineering and Technology Centre of Lake Research Centre of Lake Environment State Env. Protection Key Lab. for Lake Pollution Control State Key Lab. of Env. Criteria and Risk Assessment Chinese Research Academy of Env. Sciences Beijing 100012 China School of Resource and Environmental Sciences East China Normal University Shanghai 200062 China

ISBN: (纸本)9783037855683

Aeration was one of the common techniques which were focused in environmental engineering research. In this study, experiments were carried out to investigate the effect of aeration on nitrogen (N) fractions and its transformation in the sediment-water interface from urban lake. In addition, we measured the dehydrogenase (DHA) and Chla content in surface sediment to detect the changes of the microbial activity. The aim is to explore the regulation of N migration and transformation in the water-sediment interface during the treatment work of lake pollution. By mechanical aeration, we control the DO content of the overlying water at the range of 1.2-1.5 kg/L, 2.5-4.5 mg/L and 6.1-6.2 mg/L. Results showed that DO in overlying water play a role to the variation of N in water-sediment interface. NH4+-N was the mainly N fraction released from sediment, the lower DO concentration (1.2-1.5 mg/L) in overlying water is favorable to the release of NH4+-N from sediment. Whether under aerobic or anaerobic condition, the releasing of NH4+-N from sediment were both higher than its consumption in the overlying water. The benthic microbial activity of the surface sediment (0-2 cm) was higher than that from bottom (6-8 cm). And the microbial activity in surface sediment was in optimum range when the overlying water DO content was about 2.5-4.5 mg/L. © (2013) Trans Tech Publications, Switzerland.

关键词： Nitrogen

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Energy-efficient area coverage in bistatic radar sensor networks

Energy-efficient area coverage in bistatic radar sensor netw...

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2013 IEEE Global Communications Conference (GLOBECOM)

作者： Qianqian Yang Shibo He Jiming Chen State Key Lab. of Indnsrrial Control Technology Zhejiang University China School of Electrical Computer and Energy Engineering Arizona State University USA

ISBN: (纸本)9781479913510

In this paper we study area coverage in bistatic radar sensor networks (BRSN), which is composed of a collection of transmitters and receivers. Coverage in BRSN is much more difficult than that in traditional sensor networks as the sensing area of a bistatic radar depends on the positions of its component transmitter and receiver, and is in general of an elliptical shape. We first investigate the geometrical relationship between the c-coverage area of a bistatic radar and the distance between its component transmitter and receiver, based on which we reduce the number of candidate bistatic radars from all transmitter-receiver pairs. Then we reduce the problem dimension by transforming the area coverage problem to point coverage problem by employing intersection point concept. Finally we propose an efficient algorithm to solve the Point Coverage Problem, which thus solves the area coverage problem. We perform extensive simulations to validate our analysis and the performance of the proposed algorithm.

关键词： Bistatic radar Receivers Algorithm design and analysis Radio transmitters Sensors

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Development of concept analysis and multi-objective optimization platform for body-in-white structure

Development of concept analysis and multi-objective optimiza...

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FISITA 2012 World Automotive Congress

作者： Li, Yiwen Li, Hongjian Pan, Zuofeng Xu, Tao R and D Center FAW Changchun China State Key Lab. of Comprehensive Technology on Automobile Vibration and Noise and Safety Control China FAW Co.Ltd. R and D Center Changchun China College of Mechanical Science and Engineering Jilin University Jilin China

ISBN: (纸本)9783642338342

To achieve the integrated control of body-in-white (BIW) performance at the concept design stage, several parametrical optimization technologies are proposed in this paper in seeking lightweight, stiffness and crashworthiness targets. A professional platform - Concept Analysis and Multi-objective Optimization (CAMO) is developed, which has the capability of the rapid reduction, parametrical simulation and optimization. The optimization algorithms database is developed based on. NET framework to ensure the global convergence and robustness of the optimal results. The theories discussed in the paper are great help of the concept design process improvement, body database development and knowledge utilization. © Springer-Verlag 2013.

关键词： Multiobjective optimization

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Design and implementation of automatic voltage control system applied to a power grid in Northeast US

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Dianwang Jishu/Power System Technology 2013年第2期37卷 349-355页

作者： Zhang, Mingye Guo, Qinglai Sun, Hongbin Tong, Jianzhong Zhang, Boming Wu, Wenchuan Wang, Bin State Key Lab. of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Haidian District Beijing 100084 China PJM Interconnection PA 19403 United States

With the raising of requirement of power grid operation to voltage control and reactive power management level, automatic voltage control (AVC) becomes a hot spot in the research. Due to the constraints in the management mode, the applied research of AVC is hitherto a blank in North America power grids. An AVC system, which is suitable to special management modes of a certain interconnected power grid in Northeast U. S. and can meet the demand of on-line operation, is designed and implemented. In the designed system, phase shifter models are added into power flow modules and during the computation of control strategy by optimal power flow (OPF) the static security constraints after the assumed faults are considered. Both the data and assessment results of long-term on-line trail-operation show that the reactive power and voltage level of the interconnected power grid can be improved by applying the designed AVC system, and both security and economy of the interconnected power grid can be enhanced.

关键词： Electric power system control

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A non-iterative affine arithmetic methodology for interval power flow analysis of transmission network

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Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical engineering 2013年第19期33卷 76-83页

作者： Ding, Tao Bo, Rui Guo, Qinglai Sun, Hongbin Wu, Wenchuan Zhang, Boming State Key Lab. of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua University Haidian District Beijing 100084 China Midwest ISO St. Paul 55108 United States

Power flow exhibits uncertainty when power injections randomly fluctuate. The variables of power flow problem are correlated through the constraints set forth by power flow equations. Affine arithmetic can effectively overcome the correlation and therefore is adopted in this paper. In order to improve the computational efficiency, non-iterative method was proposed, which can transform the interval power flow problem into optimization problems. Linear programming, nonlinear programming and quadratic programming optimization models were established to obtain intervals of nodal voltage magnitude, phase angle, branch active power and reactive power, respectively. Simulation results of 9-bus and 57-bus test system show that the power flow interval obtained by the proposed algorithm is nearly the same as that by iterative algorithms, whereas the branch power flow results are better. The interval power flow problem can be solved quickly and efficiently with time complexity approximately O(m3). As well, parallel computing can be implemented to achieve promising improvement in computation time. © 2013 Chinese Society for Electrical engineering.

关键词： Quadratic programming

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Performance analysis for high-speed railway communication network using stochastic network calculus

Performance analysis for high-speed railway communication ne...

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5th IET International Conference on Wireless, Mobile and Multimedia Networks, ICWMMN 2013

作者： Li, Ying Lei, Lei Zhong, Zhangdui Lin, Siyu School of Electronics and Information Engineering Beijing Jiaotong University Beijing 100044 China State Key Lab. of Rail Traffic Control and Safety Beijing Jiaotong University Beijing 100044 China Dept. of Electrical and Computer Engineering University of Victoria Victoria BC V8P 5C2 Canada

ISBN: (纸本)9781849197267

High-speed railway (HSR) wireless communication network has won a great development in recent years. However, due to its unique characteristics, such as high speed, fixed mobility track, special traffic, frequent handover and bandwidth constraints, it is quite a challenge to carry out the performance analysis on HSR. In this paper, we derive the backlog and delay bounds for HSR communication network by using stochastic network calculus (SNC) with moment generating functions (MGFs). SNC is a highly useful tool in packet switched network performance analysis since 1990s. Different from the previous studies about SNC which mostly concentrate on general low-speed, traditional public communication network, we take the varying small-scale fading and large-scale fading into consideration by means of a novel multi-dimension finite-state Markov channel (FSMC) model. We elab.rate the differences in packet-level channel model, traffic model of train control information and performance metrics in HSR communication network. Particularly, the backlog and delay bounds of HSR with different packet arrival rates and violation probabilities are derived when train travels from the cell center to the cell edge. What is more, the numerical results can help to provide a guideline for designing the proper violation probabilities and arrival rates to different types of traffic in HSR communication network.

关键词： Calculations

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Output Characteristics of a Series Three-port Axial Piston Pump

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Chinese Journal of Mechanical engineering 2012年第3期25卷 498-505页

作者： ZHANG Xiaogang QUAN Long YANG Yang WANG Chengbin YAO Liwei Institute of Mechatronics Engineering Taiyuan University of TechnologyTaiyuan 030024 The State Key Lab of Fluid Power Transmission and Control Zhejiang University Hangzhou 310027

Driving a hydraulic cylinder directly by a closed-loop hydraulic pump is currently a key research area in the field of electro-hydraulic control technology,and it is the most direct means to improve the energy efficiency of an electro-hydraulic control *** far,this technology has been well applied to the pump-controlled symmetric hydraulic ***,for the differential cylinder that is widely used in hydraulic technology,satisfactory results have not yet been achieved,due to the asymmetric flow ***,based on the principle of the asymmetric valve controlled asymmetric cylinder in valve controlled cylinder technology,an innovative idea for an asymmetric pump controlled asymmetric cylinder is put forward to address this *** scheme proposes to transform the oil suction window of the existing axial piston pump into two series *** in use,one window is connected to the rod chamber of the hydraulic cylinder and the other is linked with a low-pressure oil *** allows the differential cylinders to be directly controlled by changing the displacement or rotation speed of the *** with the loop principle of offsetting the area difference of the differential cylinder through hydraulic valve using existing technology,this method may simplify the circuits and increase the energy efficiency of the *** the software SimulationX,a hydraulic pump simulation model is set up,which examines the movement characteristics of an individual piston and the compressibility of oil,as well as the flow distribution area as it changes with the rotation *** pump structure parameters,especially the size of the unloading groove of the valve plate,are determined through digital *** of the components of the series arranged three distribution-window axial piston pump are designed,based on the simulation analysis of the flow pulse characteristics of the pump,and then the prototype pump is *** basic characteristics,su

关键词： axial piston pump pump controlled cylinder simulation experiment

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Jamming attack on Cyber-Physical Systems: A game-theoretic approach

Jamming attack on Cyber-Physical Systems: A game-theoretic a...

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IEEE International Conference on Cyber Technology in Automation, control, and Intelligent Systems

作者： Yuzhe Li Ling Shi Peng Cheng Jiming Chen Daniel E. Quevedo Electronic and Computer Engineering Hong Kong University of Science and Technology Hong Kong State Key Lab. of Industrial Control Technology Zhejiang University China School of Electronic Engineering and Computer Science University of Newcastle Australia

We consider security issues in Cyber-Physical Systems (CPSs). A sensor node communicates with a remote estimator through a wireless channel which may be jammed by an external attacker. With energy constraints for both the sensor and the attacker, the interactive decision making process of when to send and when to attack is studied. We formulate a game-theoretical framework and prove that the optimal strategies for both sides constitute a Nash equilibrium. The derivation of the optimal strategies for both sides is also provided with examples.

关键词： Games Nash equilibrium Tin Linear programming Computer crime

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Cooperative and Active Sensing in Mobile Sensor Networks for Scalar Field Mapping

Cooperative and Active Sensing in Mobile Sensor Networks for...

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IEEE International Conference on Automation Science and engineering

作者： Hung Manh La Weihua Sheng Jiming Chen Center for Advanced Infrastructure and Transportation (CAIT) Rutgers University Piscataway NJ 08854 USA School of Electrical and Computer Engineering Oklahoma State University Stillwater OK 74078 USA State Key Lab. of Industrial Control Technology Department of Control Zhejiang University Hangzhou P.R.China 310027

ISBN: (纸本)9781479915132

Scalar field mapping has many applications including environmental monitoring, search and rescue, etc. In such applications there is a need to achieve a certain level of confidence regarding the estimates at each location. In this paper, a cooperative and active sensing framework is developed to enable scalar field mapping using multiple mobile sensor nodes. The cooperative and active controller is designed via the real-time feedback of the sensing performance to steer the mobile sensors to new locations in order to improve the sensing quality. During the movement of the mobile sensors, the measurements from each sensor node and its neighbors are taken and fused with the corresponding confidences using distributed consensus filters. As a result an online map of the scalar field is built with a certain level of confidence of the estimates. We conducted computer simulations to validate and evaluate our proposed algorithms

关键词： Active sensing Sensor fusion Sensor networks

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