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top-k query Framework in Wireless Sensor Networks for Smart Grid

China Communications 2014年第6期11卷 89-98页

作者： WANG Hui GUAN Zhitao YANG Tingting XU Yue School of economics and management North China Electric Power University

The smart grid has caught great attentions in recent years, which is poised to transform a centralized, producer-controlled network to a decentralized, consumer- interactive network that＇s supported by fine-grained monitoring. Large-scale WSNs （Wireless Sensor Networks） have been considered one of the very promising technologies to support the implementation of smart grid. WSNs are applied in almost every aspect of smart grid, including power generation, power transmission, power distribution, power utilization and power dispatch, and the data query processing of ＇WSNs in power grid＇ become an hotspot issue due to the amount of data of power grid is very large and the requirement of response time is very high. To meet the demands, top-k query processing is a good choice, which performs the cooperative query by aggregating the database objects＇ degree of match for each different query predicate and returning the best k matching objects. In this paper, a framework that can effectively apply top-k query to wireless sensor network in smart grid is proposed, which is based on the cluster-topology sensor network. In the new method, local indices are used to optimize the necessary query routing and process intermediate results inside the cluster to cut down the data traffic, and the hierarchical join query is executed based on the local ***, top-k query results are verified by the clean-up process, and two schemes are taken to deal with the problem of node＇s dynamicity, which further reduce communication cost. Case studies and experimental results show that our algorithm has outperformed the current existing one with higher quality results and better efficiently.

关键词： smart grid wireless sensornetwork top-k query framework.

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Probabilistic top-k query:Model and Application on Web Traffic Analysis

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China Communications 2016年第6期13卷 123-137页

作者： Xiaolin Gui Jun Liu Qiujian Lv Chao Dong Zhenming Lei Beijing key Laboratory of Network System Architecture and Convergence Beijing University of Posts and TelecommunicationsBeijing100876China Agricultural Bank of China Beijing 100161 China

top-k ranking of websites according to traffic volume is important for Internet Service Providers(ISPs) to understand network status and optimize network resources. However, the ranking result always has a big deviation with actual rank for the existence of unknown web traffic, which cannot be identified accurately under current techniques. In this paper, we introduce a novel method to approximate the actual rank. This method associates unknown web traffic with websites according to statistical probabilities. Then, we construct a probabilistic top-k query model to rank websites. We conduct several experiments by using real HTTP traffic traces collected from a commercial ISP covering an entire city in northern China. Experimental results show that the proposed techniques can reduce the deviation existing between the ground truth and the ranking results vastly. In addition, we find that the websites providing video service have higher ratio of unknown IP as well as higher ratio of unknown traffic than the websites providing text web page service. Specifically, we find that the top-3 video websites have more than 90% of unknown web traffic. All these findings are helpful for ISPs understanding network status and deploying Content Distributed Network(CDN).

关键词： top-k query traffic model temporal bipartite graph uncertain data unknown traffic

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Optimizing Distributed top-k Queries on Uncertain Data

Optimizing Distributed Top-k Queries on Uncertain Data

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第25届中国控制与决策会议

作者： Zhao Zhibin Yu Yang Bao Yubin Yu Ge School of Information Science and Engineering Northeastern University

ISBN: (纸本)9781467355339

With the advances in technology of CPS （Cyper Physical System）, it is found that uncertain data arises in many important domains, such as WSN, RFID, P2P system, and so on. It poses a great challenge on top-k query processing, which is a very common and crucial application in data management. In this paper, we summarize several semantics of top-k queries on uncertain data and propose an optimized algorithm DMPUtop-k for processing most probable uncertain top-k queries（MPUtop-k） in the distributed environment. In addition, we analyze the equivalence between MPUtop-k and Utop-k in some special cases. The experiments on real dataset show that our technique can greatly reduce the bandwidth consumption for processing top-k queries in distributed uncertain dataset.

关键词： top-k query uncertain data distributed environment optimization transmission cost

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P2P环境下数据管理系统上的top-k查询(英文)

P2P环境下数据管理系统上的Top-k查询(英文)

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第二十二届中国数据库学术会议

作者：何盈捷文继军冯月利王珊中国人民大学信息学院

Most of existing peer-to-peer(P2P) systems only provide coarsely granular file-level sharing and lack of data management ability.A new framework of database sharing in P2P network is presented,which is based on keyword search over relational *** the framework,database on each peer can be seen as a text collection,users needn’t care about the schema information of the database,which greatly simplifies the schema mapping between different peers,and is more suitable for the decentralization and dynamicity of P2P *** top-k query processing algorithm based on histogram is applied in the data management system in P2P network to do top-k query,which unifies the query over text collections and relational *** the query processing,histogram can be updated automatically by using the returned top k results,and the neighborhood of the peer can be self reconfigured to let the nodes containing the real top k results to be its *** results show that database sharing based on the keyword searching breaks through the traditional database sharing schema and simplifies the data accessing method,and top-k query based on histogram improves the search efficiency.

关键词： Peer-to-peer Database sharing keyword query top-k query Histogram Neighborhood self reconfiguration

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网格环境下的数据库检索系统设计与实现

网格环境下的数据库检索系统设计与实现

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第二十二届中国数据库学术会议

作者：王韵婷刘焕章文继军王珊中国人民大学信息学院

1引言进入本世纪初,网格技术的应用逐渐从单纯的科学计算领域扩展到企业应用,研究热点也从计算网格、数据网格转向到了服务网格、信息网格。信息网格是利用网格技术实现信息的共享、管理和信息

关键词： Grid Relational database Information retrieval keyword query top-k query GDBIR

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