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

作者： Fu, Cong Li, Xu Ai, Bo School of Electronics and Information Engineering Beijing Jiaotong University Beijing China State Key Lab. of Rail Traffic Control and Safety Beijing Jiaotong University Beijing China

ISBN: (纸本)9781849197267

Viterbi decoder is a common module in communication system, which has the requirements of low power and low decoding latency. In this paper, based on path merging property, a dynamic truncation length algorithm and memory architecture is proposed to reduce memory access operations of survivor management. The result shows that more than 30% memory access operations can be reduced with almost no degradation of the error correction capability, and the increased hardware costs is very low. Using this architecture and pipelined Add-Compare-Select operation, we can get a low-latency, power efficient Viterbi decoder.

关键词： Memory architecture

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A tapped delay-based channel model for vehicle-to-vehicle communications

A tapped delay-based channel model for vehicle-to-vehicle co...

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

作者： Wang, Qi Ai, Bo Liu, Lixia Zhong, Zhangdui State Key Lab. of Rail Traffic Control and Safety Beijing Jiaotong University Beijing China University of Armed Police Force Engineering Shaanxi Xi'an 710086 China

ISBN: (纸本)9781849197267

In this paper, we propose a new tapped delay-based channel model for Vehicle-to-Vehicle (V2V) communications. Both the well-known tapped delay line (TDL) method and the Geometry-based Stochastic Channel Modeling (GSCM) method are combined in our proposed channel model. Firstly, we use the tapped delay to build a multiple ellipses model, and then use the ray-tracing method to get the impulse responses (IRs). At last, the simulation results of four different campaigns, including the impulse response, power delay profile, delay spreads and spectrum spread are presented.

关键词： Impulse response

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Multi-antenna transmission schemes in high speed railway communication

Multi-antenna transmission schemes in high speed railway com...

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

作者： Li, Zhao Wang, Fanggang Zhong, Zhangdui School of Electronics and Information Engineering Beijing Jiaotong University Beijing China State Key Lab. of Rail Traffic Control and Safety Beijing Jiaotong University Beijing China

ISBN: (纸本)9781849197267

With the rapid development of wireless communication technology, the communication in high speed railway (HSR) is confronted with the trend of Long Term Evolution for Rail (LTE-R), which will unprecedentedly improve the transmission rate and data reliability. In this paper, we present three different multi-antenna schemes for HSR, including conventional MIMO, spatial modulation and massive MIMO. The merits and drawbacks of these schemes are discussed. After that we make simulations about space-time coding, V-BlAST, and spatial modulation. Numerical results indicate that spatial modulation has great potential in HSR communication and that extra receive antennas can bring additional gains.

关键词： Modulation

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Unloading features analysis of a new combined unloading system

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International Conference on Informatics and Management Science, IMS 2012

作者： Sun, Kang Tan, Jianping Si, Yuxiao School of Mechanical and Electrical Engineering Central South University Changsha 410083 China State Key Lab. of Fluid Power Transmission and Control Zhejiang University Hangzhou 310007 China

ISBN: (纸本)9781447147954

A new combined unloading system of large-scale hydraulic press was designed and combined simulation was also executed. By simulation, unloading response characteristics in varying working conditions and the effect of component parameter to unloading response characteristics in unloading process were got. The research showed that three-order cartridge valve of drainage type can realize smooth and fast unloading in high pressure working condition. Unloading speed is proportional to opening degree of pilot throttle valve. © 2013 Springer-Verlag.

关键词： Unloading

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Analytical modeling of link duration for vehicular ad hoc networks in urban environment

Analytical modeling of link duration for vehicular ad hoc ne...

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10th ACM International Workshop on Vehicular Inter-Networking, Systems, and Applications, VANET 2013

作者： Hu, Miao Zhong, Zhangdui Zhu, Haoqing Ni, Minming Chang, Chih-Yung State Key Lab. of Rail Traffic Control and Safety Beijing Jiaotong University Beijing China Dept. of Computer Science and Information Engineering Tamkang University Taipei Taiwan

ISBN: (纸本)9781450320733

Link duration determines the performance of many vehicular applications, especially for urban vehicular wireless communication networks. However, the theoretical analysis on link properties is always complicated, since parameters that should be considered include the inter-vehicle distance, the vehicle speed, the turning ratios in the intersection, the influence of traffic lights in the intersections, and the signal decay caused by the roadside buildings etc. To reduce the analytical complexity, most of the previous works proposed preliminary analysis on link duration property by considering some parameters. Even though some works considered all parameters, their assumptions on the parameters setting were somewhat ideal. For example, the events of meeting traffic lights for two consecutive vehicles in a communication route path were always assumed independent with each other, which is different from the actual situations. This paper proposes a discrete Markov process-based analytical model on link duration by considering a relatively complete set of parameters, including the influence of the inter-vehicle distance, vehicle speed, turning ratios in the intersection, traffic lights in the intersection, and the non-line-of-sight transmission for the intersection. Especially, the theoretical study on the link duration is based on a more realistic traffic lights scenario description model. Finally, simulations are carried to verify the accuracy of our analytical work.

关键词： Analytical models

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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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2013 IEEE International Conference on Automation Science and engineering, CASE 2013

作者： La, Hung Manh Sheng, Weihua Chen, Jiming Rutgers University Piscataway NJ 08854 United States School of Electrical and Computer Engineering Oklahoma State University Stillwater OK 74078 United States State Key Lab. of Industrial Control Technology Department of Control Zhejiang University Hangzhou 310027 China

ISBN: (纸本)9781479915156

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. © 2013 IEEE.

关键词： Sensor nodes

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RE-AODV: Improved AODV routing protocol for repairing efficiency

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Journal of Networks 2013年第11期8卷 2467-2472页

作者： Li, Xu Feng, Qijing Li, Shijie Ding, Haiyang School of Electronic and Information Engineering State Key Lab. of Rail Traffic Control and Safety Beijing Jiaotong University Beijing China School of Electronic and Information Engineering Beijing Jiaotong University Beijing China College of Information Engineering Beijing Institute of Graphic Communication National Beijing 102600 China Information Security Center Beijing University of Posts and Telecommunications Beijing 100876 China

Mobile Ad Hoc Network (MANET) is a self-organized, quickly configurable network, which does not have fixed infrastructure. Mobility is one of the most characteristic in MANET, but it may cause the failure of a valid link. There are two repair mechanisms-local repair and source repair in Ad hoc on demand distance vector protocol (AODV). The source repair mechanisms will bring higher overhead and packet loss ratio. Local Repair is an effective way to rebuild a route to destination, but its performance decline when the destination is unreachable from local repair node. This paper proposes an improved repair mechanism (RE-AODV) based on the local repair scheme, which distinguishes different route request messages and route reply messages with Local_Repair and Dst_Answer flags, and process them with different priorities. The simulation results demonstrate that the network delivery ratio can be significantly improved by using the proposed repair scheme. © 2013 ACADEMY PUBLISHER.

关键词： Repair

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Online routing of two vehicles to an emergency scene in grid transportation network

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Xitong Gongcheng Lilun yu Shijian/System engineering Theory and Practice 2013年第1期33卷 175-180页

作者： Xu, Yin-Feng Zhang, Hui-Li Yu, Hai-Yan Zhang, Wen-Ming School of Management Xi'an Jiaotong University Xi'an 710049 China Ministry of Education Key Lab. for Process Control and Efficiency Engineering Xi'an Jiaotong University Xi'an 710049 China State Key Lab. for Manufacturing Systems Engineering Xi'an 710049 China

The online routing problem of two vehicles to an emergency scene is considered. In grid transportation network, some of the edges may be suddenly blocked and the blockage will not be observed until reaching an endpoint of the blocked edge. The goal is to minimize the arrival time of the first vehicle with at most k blockages. An online strategy named Row-first and Line-first is presented and the competitive ratio is analyzed, and the ratio is proved to be tight. The optimization of the online strategy in some situations is also proved.

关键词： Vehicles

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Analysis of NMPC algorithm based on reduced precision solution criteria

Analysis of NMPC algorithm based on reduced precision soluti...

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2013 2nd International Conference on Manufacturing engineering and Process, ICMEP 2013

作者： Wan, Jiao Na Zhang, Ju Wen Wang, Zhi Qiang Zhang, Tie Jun Wang, Ke Xin Research Institute of Highway Ministry of Transport Beijing 100088 China Institute of applied mathematics Hebei academy of sciences Shijiazhuang 050081 China State Key Lab. of Industrial Control Technology Institute of Industrial Control Department of Control Science and Engineering Zhejiang University Hangzhou 310027 China

ISBN: (纸本)9783037857076

This paper studies the stability of nonlinear model predictive control (NMPC) based on sub-optimal solution obtained under reduced precision solution (RPS) criteria. NMPC needs to solve the optimal control problem (OCP) quickly and the input is injected into the controlled plant in time. Traditional convergence criteria in optimization algorithms usually cost excessive long computation time with little improvement of solution, which results in degradation of control performance eventually. RPS criteria are new convergence criteria for deciding whether the current iterate is good enough and whether the optimization procedure should be terminated. It can terminate the optimization process timely. This work gives the proof of the rps-NMPC's property. Simulations are done to analyze the effect of disturbance, especially when computational delay exists, on the closed-loop system controlled by rps-NMPC, and demonstrate that the algorithm owns good stability when disturbance exists. © (2013) Trans Tech Publications, Switzerland.

关键词： Closed loop systems

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Energy saving control of a hydraulic manipulator using five cartridge valves and one accumulator

Energy saving control of a hydraulic manipulator using five ...

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6th IFAC Symposium on Mechatronic Systems, MECH 2013

作者： Lu, Lu Yao, Bin Liu, Zhibin School of Mechanical Engineering Purdue University 585 Purdue Mall West Lafayette 47907 IN United States State Key Lab. of Fluid Power Transmission and Control Zhejiang University Yuquan Campus Hangzhou 310027 China

ISBN: (纸本)9783902823311

In this paper, a novel energy-saving control strategy is proposed for the accurate motion tracking of a hydraulic manipulator. To achieve independent pressure regulation for each chamber of the cylinder as well as energy recovery during the back-and-forth movement of the cylinder, a hardware configuration with five low-cost programmable cartridge valves and an accumulator is developed to control the motion of the cylinder. Based on the hardware configuration, a novel control algorithm consisting of three levels is proposed. In level I, an adaptive robust controller is synthesized to generate the desired flow rates for the two chambers of the cylinders Q1m and Q2m so that the joint angle of the manipulator tracks the desired trajectory as accurately as possible, and the offside pressure of the cylinder also follows the desired pressure profile to be generated in level III accurately. In level II, an energy-optimum flow distribution law is designed and implemented to generate the desired flow rates passing through the five programmable valves. In level III, the desired offside pressure of the cylinder is generated so that the total energy consumption during the whole movement cycle is minimized. Experimental study validates that the proposed strategy can indeed achieve both accurate motion tracking and minimum energy consumption simultaneously. Compared to the previous 4-valve scheme and 5-valve flow regeneration scheme without the use of accumulator in Liu and Yao (2008), the proposed strategy has much less total energy consumption and equally good tracking performance. © 2013 IFAC.

关键词： Energy conservation

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