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Chinese Journal of Mechanical Engineering 2002年第1期15卷 87-89页

作者： Zhang Qingying logistics Engineering Department，Wuhan University of technology，Wuhan 430063，china logistics Engineering Departiment Wuhan University of Technology Wuhan 430063

Computer vision and its application in the precision control system arediscussed. In the process of fabricating, the accuracy of the products should be controlledreasonably and completely. The precision should be kept and adjusted according to the information offeedback got from the measurement on-line or out-line in different procedures. Computer vision isone of the useful methods to do this. Computer vision and the image manipulation are presented, andbased on this, a n-dimensional vector to appraise on precision of machining is given.

关键词： Computer vision Measurement Precision Quality of products

VMStore: Distributed storage system for multiple virtual machines

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Science china(Information Sciences) 2011年第6期54卷 1104-1118页

作者： LIAO XiaoFei, LI He, JIN Hai , HOU HaiXiang, JIANG Yue & LIU HaiKun Services Computing technology and system lab, Cluster and Grid Computing lab, School of Computer Science and technology, Huazhong University of Science and technology, Wuhan 430074, china 1. Services Computing technology and system lab Cluster and Grid Computing Lab School of Computer Science and Technology Huazhong University of Science and Technology Wuhan 430074 China

Desktop virtualization is a very hot concept in both industry and academic communities. Since virtualized desktop system is based on multiple virtual machines (VM), it is necessary to design a distributed storage system to manage the VM images. In this paper, we design a distributed storage system, VMStore, by taking into account three important characteristics: high performance VM snapshot, booting optimization from multiple images and redundancy removal of images data. We adopt a direct index structure of blocks for VM snapshots to speed up VM booting performance significantly; provide a distribute storage structure with good bandwidth scalability by dynamically changing the number of storage nodes; and propose a data preprocessing strategy with intelligent object partitioning techniques, which would eliminate duplication more effectively. Performance analysis for VMStore focuses on two metrics: the speedup of VM booting and the overhead of de-duplication. Experimental results show the efficiency and effectiveness of VMStore.

关键词： virtualization virtualized desktop distributed storage

Implementation of ITU-T G.729 Speech Codec in IP Telephony Gateway

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Wuhan University Journal of Natural Sciences 2000年第2期5卷 159-163页

作者： HUANG Yong feng,ZHANG Jiang ling National Storage system lab, School of Computer, Huazhong University of Science & technology, Wuhan 430074,china Huazhong University of Science & technology National Storage System Lab School of Computer Wuhan China (GRID:grid.33199.31) (ISNI:***)

ITU-T G. 729 is the primarily recommended speech codec by H. 323 standard. This paper describes how to implement G. 729 codec in IP telephony gateway, and goes deep into the programming skills on TMS320C6201 DSP and optimizing methods of program code to reduce the speech processing delay time of G. 729 codec. Due to adopting these optimizing methods and programming skills, we have implemented a high-speed speech codec that can process concurrently 20 voice channels with single TMS320C6201 chip in IP telephony gateway. Finally, the paper analyzes the performance results of ITU-T G. 729 codec based on TMS320C6201.

关键词： Key words ITU T G. 729 IP telephony gateway speech codec

Optimum Transmitter Power Control in WCDMA Cellular systems

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Journal of systems Engineering and Electronics 2002年第1期13卷 80-86页

作者： Qiu Ling & Zhu Jinkang PCN&SS lab., University of Science and technology of china, Hefei 230027, P.R. china PCN&SS lab. University of Science and Technology of China Hefei 230027 P.R. China

Power control is an important technique in WCDMA mobile systems for both increasing system capacity and guaranteeing the required QoS (time delay and wireless link transmission quality) of multimedia services. The optimum power control for narrow band CDMA cellular systems is a problem of single threshold optimization. Because these systems have only one type of traffic and have the same QoS requirement. However, WCDMA mobile system should provide multimedia services and different types of traffic have different QoS requirements. Thus, the power control in WCDMA mobile systems isn't a problem of single threshold optimizing, but turns into the optimizing problem of multi-threshold. We analyze the power control problem in WCDMA cellular mobile systems and propose the optimum transmitter power control algorithm. Three criteria to optimize transmitter power levels of multi-thresholds based on grading the priority orders of multimedia services are proposed. Simulation results show that the proposed algorithms are more effective than conventional algorithms and can provide better performance for WCDMA cellular mobile systems.

关键词： Cellular radio systems Code division multiple access Mobile telecommunication systems Multimedia systems Optimization Quality of service

Adaptive neural control based on HGO for hypersonic flight vehicles

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Science china(Information Sciences) 2011年第3期54卷 511-520页

作者： XU Bin 1,2 , GAO DaoXiang 3 & WANG ShiXing 1 1 Department of Computer Science and technology, Tsinghua University, Beijing 100084, china 2 Autonomous system lab, ETH Zurich Zurich 8092, Switzerland 3 School of technology, Beijing Forestry University, Beijing 100083, china 1. Department of Computer Science and technology Tsinghua University Beijing 100084 China2. Autonomous System Lab ETH Zurich Zurich 8092 Switzerland3. School of Technology Beijing Forestry University Beijing 100083 China

This paper describes the design of adaptive neural controller for the longitudinal dynamics of a generic hypersonic flight vehicle (HFV) which are decomposed into two functional systems, namely the altitude subsystem and the velocity subsystem. For each subsystem, one adaptive neural controller is investigated based on the normal output-feedback formulation. For the altitude subsystem, the high gain observer (HGO) is taken to estimate the unknown newly defined states. Only one neural network (NN) is employed to approximate the lumped uncertain system nonlinearity during the controller design which is considerably simpler than the ones based on back-stepping scheme with the strict-feedback form. The Lyapunov stability of the NN weights and filtered tracking error are guaranteed in the semiglobal sense. Numerical simulation study of step response demonstrates the effectiveness of the proposed strategy in spite of system uncertainty.

关键词： adaptive neural control hypersonic flight vehicle high gain observer output-feedback

Study on the Formability of Iron-Based Powder Metal Materials in Plasma Arc Direct Metal Forming Process

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稀有金属材料与工程 2011年第S4期40卷 266-269页

作者： Xia Dan1,Xiang Yonghua2,Xu Binshi 1,Lv Yaohui 11Science and technology on Remanufacturing laboratory,Beijing 100072,china2Navy logistics technology and Equipment Institute of PLA,Beijing 100072,china Sci & Technol Remfg lab Beijing 100072 Peoples R China Navy Logist Technol & Equipment Inst PLA Beijing 100072 Peoples R China

The specific Fe-based alloy for direct metal forming was designed and prepared under multi-layer cladding *** powder was designed for getting the better formability,toughness and *** experiment used KR6 robot and NW5000 digital power supply as the hardware *** and hardness of the layer formed by different powder were analyzed by using X-ray diffraction (XRD) and Transmission Electron Microscope (TEM).The result shows that thermal expansion coefficient correlated with processing formability is not *** of the layers is correlated to elements phase of the coatings was formed by γ(FeNi) and α(FeCrNi),and a little Cr23C6、Fe3Si and MoO2.

关键词： plasma arc direct metal forming iron-based powder

CONTROLLED/"LIVING" RADICAL POLYMERIZATION OF STYRENE IN AN AQUEOUS DISPERSION system

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Chinese Journal of Polymer Science 2002年第5期20卷 445-451页

作者： Bin Zhang Zhao-bin Zhang Xiao-long Wan Chun-pu Hu Sheng-kang Ying lab of Living Polymerization, East china University of Science and technology.Shanghai 200237,china E china Univ Sci & Technol Lab Living Polymerizat Shanghai 200237 Peoples R China

Atom transfer radical polymerization (ATRP) of styrene catalyzed by cuprous (CuX)/1,10-phenanthroline (Phen) and CuX/CuX2/Phen was conducted in an aqueous dispersed system. A stable latex was obtained by using ionic surfactant sodium lauryl sulfonate (SLS) or composite surfactants, such as SLS/polyoxyethylene nonyl phenyl ether (OP-10), SLS/hexadecanol and SLS/OP-10/hexadecanol, Among which SLS and SLS/OP-10/hexadecanol systems established better dispersed effect during the polymerization, It was found that Phen was a more suitable ligand than N,N,N',N',N'-pentamethyldiethylenetriamine (PMDETA) to maintain an appropriate equilibrium of the activator Cu(I) and the deactivator Cu(II) between the organic phase and the water phase, The effect of several initiators (such as EBiB, CCl4 and 1-PEBr) and the temperature on such a kind of ATRP system was also observed. The number-average molar mass (M-n) of polystyrene (PS) increased with the conversion and the molar mass distribution (M-w/M-n) remained narrow. These experimental data show that the polymerization could be controlled except for the quick increase of monomer conversion and the number-average molar mass of PS in the initial stage of polymerization. Furthermore, the initiator efficiency was found to be low (similar to57%) in CuX/Phen catalyzed system. To overcome this problem, Cu(II)X-2 (20 mol%-50 mol% based on CuX) was introduced into the polymerization system. In this case, higher initiator efficiency (60%-90%), low M-w/M-n of PS (as low as 1.08) were achieved and the molar masses of the PS fit with the theoretical ones.

关键词： controlled/'living' radical polymerization polystyrene water dispersed polymerization 1,10-Phenanthroline

Calculation of correlation function of binary periodic sequences

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Chinese Science Bulletin 1997年第13期42卷 1065-1068页

作者： LI ChaoDepartment of system Engineering and Mathematics, National University of Defense technology, Changsha 410073, china State Key laboratory of Mobile Communication, Southeast University, Nanjing 210018, china Dept. of Syst. Eng. and Mathematics Natl. Univ. of Defense Technology Changsha 410073 China State Key lab. of Mobile Commun. Southeast University Nanjing 210018 China

SINCE Olsen and Lempel constructed a family of optimal key sequences (called Bent se-quences) by using the trace function over finite field in 1982, the theory of trace functionhas been widely used in spread-spectrum communication and cryptology. Many papers aboutconstructing pseudorandom sequences by using trace functions were published in IEEE Trans-actions on Information Theory. The sequences (such as GMW sequences, No sequences,

关键词： exponential sums quadratic forms periodic sequences correlation functions.

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基于POMDP模型的机器人行动的仿真优化

系统仿真学报 2008年第21期20卷 5903-5906页

作者：马军殷保群中国科学技术大学网络传播系统与控制联合实验室合肥230027

策略梯度优化算法是一种很重要的强化学习算法,对实现机器人的自主导航有着重要的应用价值。在部分可观Markov决策过程(POMDP)的基础上,实现了两个有限记忆的策略梯度优化算法:基于模型的GAMP算法和无模型的IState-GPOMDP算法,并利用该... 详细信息

策略梯度优化算法是一种很重要的强化学习算法,对实现机器人的自主导航有着重要的应用价值。在部分可观Markov决策过程(POMDP)的基础上,实现了两个有限记忆的策略梯度优化算法:基于模型的GAMP算法和无模型的IState-GPOMDP算法,并利用该算法对机器人走迷宫的问题进行了仿真。通过分析仿真结果,对这两种算法引入了基于观测的优化;并发现在所给报酬函数下,策略梯度算法中的步长参数也在一定程度上影响着优化策略的效率。

关键词： POMDP 强化学习策略梯度算法仿真优化