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A scalab.e peer-to-peer indexing scheme for high dimensional nearest- neighbor search in massive datasets

Journal of Convergence Information Technology 2011年第9期6卷 131-139页

作者： Liu, Dawei Zhu, Ming The Key Lab of Network Communication System and Control The Chinese Academy of Sciences University of Science and Technology of China China The Key Lab of Network Communication System and Control Anhui Department of Automation University of Science and Technology of China China

Nearest-Neighbor (NN) search is an increasingly important problem in many computer applications, in which high dimensional massive datasets are involved. In this paper, we propose a P2P distributed indexing scheme to perform NN search in massive datasets. We consider the locality sensitive hashing (LSH) scheme under lp-metric to support similarity search in high dimensional space and we put forward a novel mapping from the multi-dimensional LSH bucket space to the one dimension DHT key space using nun-uniform Hilbert Curve. We consider the requirements of both similarity search and the maintenance of P2P network. Our indexing scheme preserves the locality sensitive property of LSH indexes and guarantees load balance in DHT networks. We also show how to leverage the LSH indexing scheme to efficiently process NN search in P2P network. Experiments on real world data confirm the effectiveness and efficiency of our approach and show the scalab.lity gains compared to state-of-the-art schemes.

关键词： Nearest neighbor search

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The research on dynamic replication and placement of file using Dual-Threshold dynamic file migration algorithm

The research on dynamic replication and placement of file us...

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International Conference on Computer Science and Software Engineering, CSSE 2008

作者： Xiuyan, Guo Jim, Li Jian, Yang Jinlin, Wang Joint Lab. of Network Communication System and Control University of Science and Technology of China Hefei Anhui 230027 China DSP Center of Institute of Acoustics Chinese Academy of Sciences Beijing 100080 China

ISBN: (纸本)9780769533360

The replication and deployment of media file is one of the key issues in video-on-demand system, the replication algorithm and deployment strategy will directly affect the performance of storage balance and load balance in the system. In order to enhance the capacity of streaming media servers and handle the problem that migrating files will affect acceptance rate of user requests, in this paper we present a practical strategy to deploy and transfer files in real video-on-demand system. According to this strategy, we compute the migration probability when a file migration request comes, then we decide whether transfer files by the probability. Through analysis of experimental results and theoretical proof, the dual-threshold dynamic file migration algorithm described in this paper can improve acceptance rate of user requests and the capacity of streaming media servers. © 2008 IEEE.

关键词： Video on demand

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Indexing of constrained moving objects for current and near future positions in GIS

Indexing of constrained moving objects for current and near ...

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First International Multi- Symposiums on Computer and Computational Sciences, IMSCCS'06

作者： Jing, Guo Wei, Guo Dongru, Zhou School of Computer Science Wuhan University Wuhan 430072 China State Key Lab. of Advanced Optical Communication System and Network Shanghai Jiao Tong University Shanghai 200030 China

ISBN: (纸本)0769525814

In Geographic Information system (GIS), fast and efficiently indexing moving objects are a crucial issue in several application domains, such as LBS, Intelligence Transportation and Digital Battle. In this paper, a new index structure, PQR-tree, is proposed to fast update and efficiently index the present or near future positions of constrained moving objects based on the characters of moving objects. PQR-tree is an integrated tree structure which combined PMR Quadtree, Quadtree and R*-tree together. Firstly, QR-tree which combined Quadtree and R*-tree is used to carry out rough level partition for index space based on range region. Next, an R*-tree is used to index quasi-static objects for each subspace. Then, using a splitting rule of PMR Quadtree to carry further level partition for index space based on road networks and all fast moving objects are related to the road networks. The experimental results show that PQR-tree achieves better performance for index updating and query evaluation than TPR-tree. © 2006 IEEE.

关键词： Geographic information systems

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Step-size optimization EASI algorithm for blind source separation

Step-size optimization EASI algorithm for blind source separ...

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2007 International Conference on Computational Intelligence and Security, CIS'07

作者： Weihong, Fu Xiaoniu, Yang Naian, Liu State Key Lab. of Integrated Service Networks Xidian University Xi'an 710071 China National Laboratory of Information Control Technology for Communication System Jiaxing Zhejiang 31403 China

ISBN: (纸本)0769530729

Aiming at the problem of blind source separation of the communication signals, we propose a step size optimization equivariant adaptive source separation via independence (SO-EASI) algorithm basing on the EASI block based algorithm. This algorithm adjusts the step-size by the steepest descent method and thereby greatly increases its convergence speed whatever value the step-size is initialized. Simulation results show that SO-EASI algorithm can effectively blindly separate the communication signals and these results also support the expected improvement in convergence speed of the approach. © 2007 IEEE.

关键词： Blind source separation

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Design and implementation of low power consumption wireless pressure transmitter monitoring system

Design and implementation of low power consumption wireless ...

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2009 International Conference on Computational Intelligence and Software Engineering, CiSE 2009

作者： Wang, Quan Liu, Zhe Wang, Ping Wei, Min Ministry of Education Key Lab. of Network Control and Intelligent Instrument Chongqing University of Posts and Telecommunications Chongqing China Key Laboratory of Wireless Sensor Network and Communication Shanghai Institute of Microsystem and Information Technology Chinese Academy of Sciences Shanghai China

ISBN: (纸本)9781424445073

Recent years have seen a burgeoning interest in industrial wireless network with applications ranging from filed monitoring to controlling. Industrial wireless network have several important attributes that require special attention to device design which include the need for inexpensive, long-lasting, highly reliable devices coupled with very low performance requirements. Aimed at key issues of limited battery energy and reduction power consumption, combined with the soul of intelligent instrumentation a low-power consumption design of wireless pressure transmitter was proposed and realized. This paper outlined the system design, and introduced the design of the network protocol stack structure with sleep-wakeup mechanism in detail. The testing and analysis results show that the system has both high stability and great low-power consumption. ©2009 IEEE.

关键词： network protocols

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Direct multi-hop time synchronization with constructive interference

Direct multi-hop time synchronization with constructive inte...

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11th ACM/IEEE Conference on Information Processing in Sensing networks, IPSN'12

作者： Wang, Yin Pan, Gaofeng Huang, Zhiyu MOE Key Lab. for Information System Security School of Software TNLIST China Science and Technology on Communication Information Security Control Laboratory China Institute of Software Chinese Academy of Sciences China

ISBN: (纸本)9781450312271

Multi-hop time synchronization in wireless sensor networks (WSNs) is often time-consuming and error-prone due to random time-stamp delays for MAC layer access and unstable clocks of intermediate nodes. Constructive interference (CI), a recently discovered physical layer phenomenon, allows multiple nodes transmit and forward an identical packet simultaneously. By leveraging CI, we propose direct multi-hop (DMH) time synchronization by directly utilizing the time-stamps from the sink node instead of intermediate nodes, which avoids the error caused by the unstable clock of intermediate nodes. DMH doesn't need decode the flooding time synchronization beacons. Moreover, DMH explores the linear regression technique in CI based time synchronization to counterbalance the clock drifts due to clock skews. © 2012 ACM.

关键词： Synchronization

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A dynamic programming algorithm for QoS-aware replica placement in distributed caching systems

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Journal of Convergence Information Technology 2012年第12期7卷 226-234页

作者： Wang, Biyao Wang, Jinlin Liu, Xue The Key Lab of Network Communication System and Control The Chinese Academy of Sciences The Key Lab of Network Communication System and Control Anhui Department of Automation University of Science and Technology China National Network New Media Engineering Research Center Institute of Acoustics Chinese Academy of Sciences China

The rapid growth of new information services, especially like new media services, providing content distribution to clients with good quality of service(QoS) while retaining efficient is a great challenge. This paper investigates the QoS-aware replica placement problem (QRPP) for distributed caching system. We propose a dynamic programming algorithm for the problem in general graph, it first ensures the QoS requirement is satisfied of each request, then places the replica along the request forward path to minimize the total cost. The simulation results show the dynamic programming algorithm can achive a good balance between the access latency and the requested availab.lity. When the request is more concentrated, the dynamic programming algorithm can have better performance than the MODULO and LRU both in access latency and requested availab.lity.

关键词： Dynamic programming

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Virtual flux based direct power control for three-level PWM rectifier 17

Virtual flux based direct power control for three-level PWM ...

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2014 17th International Conference on Electrical Machines and systems, ICEMS 2014

作者： Yingchao, Zhang Liping, Jin Yongchang, Zhang Ting, Lu Zhengming, Zhao Key Lab. of Special Power Supply of PLA Chongqing Communication Institute China North China University of Technology Power Electronics and Motor Drive Engineering Research Center China State Key Lab. of Control and Simulation of Power System and Generation Equipments Tsinghua University China

ISBN: (纸本)9781479951611

This paper presents a new control strategy for three-level neutral point clamped (NPC) pulse width modulated (PWM) rectifier without power source voltage sensors. The relationship between instantaneous power and voltage vectors is derived mathematically. Virtual flux is estimated and used to calculate the phase of the power source voltage and instantaneous power. On these bases, a direct power control (DPC) scheme for three-level PWM rectifier is presented. An optimal switching table is established, vector switching scheme and balance strategy for the neutral point potential are discussed. Variable switching frequency and dynamic process of the startup are also analyzed. Experimental results have verified the theoretical approach and the three-level PWM rectifier with proposed DPC based on virtual flux exhibits several advantages, such as simple algorithm, low costs and excellent dynamic performance. © 2014 IEEE.

关键词： Electric rectifiers

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An Evolution Model for P2P File-Sharing networks

An Evolution Model for P2P File-Sharing Networks

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International Conference on Computer Modeling and Simulation, ICCMS

作者： Jing Huang Baoqun Yin Dong Guo Shan Lu Xumin Wu Key Lab of Network Communication System and Control University of Science and Technology Hefei China

Propose an evolution model for Peer-to-Peer (P2P) file-sharing systems, which try to capture the dynamic properties of P2P application networks. The model consists of four events: node joining, node departure, connection establishing and connection breaking, which captures the most important events in constructing network topology. The evolution model results in a differential equation about degree distribution, which can be solved analytically. By analyzing the solutions, some interesting results can be got.

关键词： network topology Peer to peer computing Complex networks Differential equations control system synthesis communication system control Crawlers Computer networks Computational modeling Computer simulation

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A Novel Dynamic Model for Peer-to-Peer File Sharing systems

A Novel Dynamic Model for Peer-to-Peer File Sharing Systems

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International Conference on Computer Modeling and Simulation, ICCMS

作者： Dong Guo Baoqun Yin Shan Lu Jing Huang Jian Yang Key Lab of Network Communication System and Control University of Science and Technology Hefei China

With widely application of Peer-to-Peer (P2P) file sharing technique, the P2P traffic occupies most of the current Internet bandwidth. Modeling the behaviors of P2P file sharing systems is important for designing and evaluating such systems. In this paper, we develop a novel model to character the dynamic behaviors of P2P sharing systems. States in microcosmic view are defined and used to describe the interaction among the peers in systems. Then, a model in general form for P2P sharing systems is proposed. According to common software policies in P2P systems, we embody the model. To verify the validity and reasonability of the proposed model, P2P simulations are conducted.

关键词： Peer to peer computing communication system traffic control Computer architecture File servers network servers control system synthesis Traffic control Bandwidth Application software Protocols

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