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Median query research in wireless sensor networks

Tien Tzu Hsueh Pao/Acta Electronica Sinica 2010年第2A期38卷 133-137页

作者： Wu, Zhong-Bo Zhang, Hui Chen, Hong Information School Renmin University of China Beijing 100872 China Key Laboratory of Data Engineering and Knowledge Engineering Ministry of Education Beijing 100872 China School of Mathematics and Computer Science Xiangfan University Xiangfan Hubei 441053 China

Poor quality and harsh condition can result in faulty and outlier data in sampling data of sensor nodes. So we need median query to reflect average level of monitoring region. First, we put forward HMA algorithm. Second, we extend HMA algorithm and put forward HFMA algorithm. In HFMA, We only need collect data inside filter and aggregate influence coefficient during sampling period. Base station can compute median result according to the sample data inside filter and influence coefficient aggregation value. Experimental results have shown that HFMA outperforms Naive algorithm and HMA algorithm and can prolong the lifetime of sensor network.

关键词： Sensor nodes

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Using link-based content analysis to measure document similarity effectively

Using link-based content analysis to measure document simila...

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Joint International Conference on Advances in data and Web Management, APWeb/WAIM 2009

作者： Li, Pei Li, Zhixu Liu, Hongyan He, Jun Du, Xiaoyong Key Labs of Data Engineering and Knowledge Engineering Ministry of Education China School of Information Renmin University of China Beijing China Department of Management Science and Engineering Tsinghua University Beijing China

ISBN: (纸本)9783642006715

Along with a massive amount of information being placed online, it is a challenge to exploit the internal and external information of documents when assessing similarity between them. A variety of approaches have been proposed to model the document similarity based on different foundations, but usually they are not applicable for combining internal and external information. In this paper, we introduce a link-based method into content analysis, which is based on random walk on graphs. By defining similarity as the meeting probability of two random surfers, we propose a computational model for content analysis, which can also be integrated with external information of documents. Empirical study shows that our method achieves good accuracy, acceptable performance and fast convergent rate in multi-relational document similarity measuring. © Springer-Verlag Berlin Heidelberg 2009.

关键词： Computers

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Exploiting the block structure of link graph for efficient similarity computation

Exploiting the block structure of link graph for efficient s...

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13th Pacific-Asia Conference on knowledge Discovery and data Mining, PAKDD 2009

作者： Pei, Li Yuanzhe, Cai Hongyan, Liu Jun, He Xiaoyong, Du Key Labs of Data Engineering and Knowledge Engineering Ministry of Education China School of Information Renmin University of China Beijing China Department of Management Science and Engineering Tsinghua University Beijing China

ISBN: (纸本)3642013066

In many real-world domains, link graph is one of the most effective ways to model the relationships between objects. Measuring the similarity of objects in a link graph is studied by many researchers, but an effective and efficient method is still expected. Based on our observation of link graphs from real domains, we find the block structure naturally exists. We propose an algorithm called BlockSimRank, which partitions the link graph into blocks, and obtains similarity of each node-pair in the graph efficiently. Our method is based on random walk on two-layer model, with time complexity as low as O(n4/3) and less memory need. Experiments show that the accuracy of BlockSimRank is acceptable when the time cost is the lowest. © Springer-Verlag Berlin Heidelberg 2009.

关键词： Artificial intelligence

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Deprank: A probabilistic measure of dependence via heterogeneous links

Deprank: A probabilistic measure of dependence via heterogen...

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Joint International Conference on Advances in data and Web Management, APWeb/WAIM 2009

作者： Li, Pei Hu, Bo Liu, Hongyan He, Jun Du, Xiaoyong Key Labs of Data Engineering and Knowledge Engineering Ministry of Education China School of Information Renmin University of China Beijing China Department of Management Science and Engineering Tsinghua University Beijing China

ISBN: (纸本)9783642006715

Dependence is a common relationship between objects. Many works have paid their attentions on dependence, but many of them mainly focus on constructing or exploiting dependence graphs on some specific domain. In this paper, we give a generic definition of dependence and make equivalence to the situation of graphs, and propose an algorithm called DepRank, which quantifies the dependence degree of a node pair based on probabilities of all dependence paths. Empirical study shows that DepRank method has reasonable results and maintains a well balance between accuracy and efficiency. © Springer-Verlag Berlin Heidelberg 2009.

关键词： Artificial intelligence

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AutoPCS: A phrase-based text categorization system for similar texts

AutoPCS: A phrase-based text categorization system for simil...

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Joint International Conference on Advances in data and Web Management, APWeb/WAIM 2009

作者： Li, Zhixu Li, Pei Wei, Wei Liu, Hongyan He, Jun Liu, Tao Du, Xiaoyong Key Labs of Data Engineering and Knowledge Engineering Ministry of Education China School of Information Renmin University of China Beijing China Department of Management Science and Engineering Tsinghua University Beijing China

ISBN: (纸本)9783642006715

Nearly all text classification methods classify texts into predefined categories according to the terms appeared in texts. State-of-the-art of text classification prefer to simplely take a word as a term since it performs good on some famous datasets;some experts even pointed out that phrases don't improve or improve only marginally the classifiction accuracy. However, we found out that this is not always true when we try to categorize texts about similar topics in the same domain. With words only we can not categorize those texts effectively since they nearly share the same word set. Then we suppose the results might be improved if we also use phrases as terms. To testify our supposition, we propose our own phrase extraction way as well as select proper feature selection method and classifier by conducting experimental study on a data set which comes from paper abstracts in the field of databases. Accordingly, we also develop a system called AutoPCS which can be used to help experts in choosing relevant topics for newly coming papers from a predefined topic list only by their abstracts. © Springer-Verlag Berlin Heidelberg 2009.

关键词： Classification (of information)

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Efficient Algorithm for Computing Link-based Similarity in Real World Networks

Efficient Algorithm for Computing Link-based Similarity in R...

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9th IEEE International Conference on data Mining

作者： Cai, Yuanzhe Cong, Gao Jia, Xu Liu, Hongyan He, Jun Lu, Jiaheng Du, Xiaoyong Key Labs of Data Engineering and Knowledge Engineering Ministry of Education China Department of Computer Science Renmin University of China China Department of Computer Science Aalborg University Denmark Department of Management Science and Engineering Tsinghua University China

ISBN: (纸本)9781424452422

Similarity calculation has many applications, such as information retrieval, and collaborative filtering, among many others. It has been shown that link-based similarity measure, such as SimRank, is very effective in characterizing the object similarities in networks, such as the Web, by exploiting the object-to-object relationship. Unfortunately, it is prohibitively expensive to compute the link-based similarity in a relatively large graph. In this paper, based on the observation that link-based similarity scores of real world graphs follow the power-law distribution, we propose a new approximate algorithm, namely Power-SimRank, with guaranteed error bound to efficiently compute link-based similarity measure. We also prove the convergence of the proposed algorithm. Extensive experiments conducted on real world datasets and synthetic datasets show that the proposed algorithm outperforms SimRank by four-five times in terms of efficiency while the error generated by the approximation is small.

关键词： Similarity Calculation SimRank Graph Mining

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IRank: A term-based innovation ranking system for conferences and scholars

IRank: A term-based innovation ranking system for conference...

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Joint International Conference on Advances in data and Web Management, APWeb/WAIM 2009

作者： Li, Zhixu Du, Xiaoyong Liu, Hongyan He, Jun Zhou, Xiaofang Key Labs of Data Engineering and Knowledge Engineering Ministry of Education China School of Information Renmin University of China Beijing China Department of Management Science and Engineering Tsinghua University Beijing China University of Queensland QLD Australia

ISBN: (纸本)9783642006715

Since the proposition of Journal Impact Factor [1] in 1963, the classical citation-based ranking scheme has been a standard criterion to rank journals and conferences. However, the reference of a paper cannot list all relevant publications and the citation relationships are not always available especially when related to copyright problem. Besides, we cannot evaluate a newly published paper before it is cited by others. Therefore, we propose an alternative method, term-based evaluation scheme which can evaluate publications by terms they use. Then we can rank conferences, journals and scholars accordingly. We think this term-based ranking scheme can be used to evaluate innovation quality for conferences and scholars. To evaluate our scheme and to facilitate its application, we develop an innovation ranking system called IRank to rank conferences and authors in the field of database Systems. The performance of IRank demonstrates the effectiveness of our scheme. © Springer-Verlag Berlin Heidelberg 2009.

关键词： Quality control

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The Electronic Records Management in E-government Strategy: Case Studies and the Implications

The Electronic Records Management in E-government Strategy: ...

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International Conference on Networking and Digital Society, ICNDS

作者： Xiaomi An Key Laboratory of Data Engineering and Knowledge Engineering Ministry of Education Renmin University of China Beijing China

Electronic records management (ERM) is fundamental to good governance, business efficiency and effectiveness of e-government in networking and digital society. However, government authorities in China has faced many challenges in managing electronic records. A study of ERM in e-government strategy in other countries would be significant to support development of ERM in Chinese e-government strategy. As little is known from literature on the status of electronic records management in e-government strategy, this paper selects U.S, New Zealand and UK for case study by means of collecting and analyzing publications, laws, regulations and policies relevant to both electronic records management and e-government strategy. The author first analyzes status of ERM in e-government strategy and then discusses models and driving forces of their existences. The result of the study revealed that electronic records are managed as national assets, resources and trusted information in the e-government strategy. Driven by core business of e-government in different country, there are different approaches to ERM in e-government strategy. The implications of the study is that, to position ERM in e-government strategy, it is significant to provide a strategic approach to ERM for shared agenda by both government authorities and records management professionals. The findings intended to be of use to both the effective e-government strategy and good ERM for dynamic, interactive and proactive citizen-centered services across domains and time dimensions.

关键词： Electronic government Conference management knowledge management engineering management Law data engineering knowledge engineering Asset management Resource management Sustainable development

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Operating systems support for process dynamic integrity measurement

Operating systems support for process dynamic integrity meas...

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IEEE Youth Conference on Information, Computing and Telecommunication, YC-ICT

作者： Chenglong Wei Shaohua Song Wen Hua Pan Bian School of Information Key Laboratory of Data Engineering and Knowledge Engineering Ministry of Education Renmin University of China Beijing China

Facing limitations of existing systems for process integrity measurement, we put forward a method with its prototype system PDIMS to measure process runtime integrity. Based on structure of process and format of executable file, PDIMS anatomizes the codepage layout of runtime process. Combining OS mechanisms and modern CPU's support for code execution, PDIMS catches and measures code page in the kernel when it executes. PDIMS depends on CPU's non-executable bit to detect code execution and on the binary format of executables of the process as criterion to verify code modifications in kernel. PDIMS provides trustworthy information about whether a running process is modified. PDIMS introduces less than 4% overhead to OS.

关键词： Operating systems Kernel Modems Computer security Runtime Protection databases knowledge engineering Prototypes Computer architecture

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Selectivity Estimation of Correlated Properties in RDF data for SPARQL Query Optimization

Selectivity Estimation of Correlated Properties in RDF Data ...

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Fifth International Conference on Semantics,knowledge and Grid(第五届语义、知识与网格国际会议 SKG 2009)

作者： Bin Lv Xiaoyong Du Yan Wang Key Laboratory of Data Engineering and Knowledge Engineering Ministry of Education School of Information Renmin University of China Beijing 100872 China

Nowadays mainstream RDF Repository Systems are based on RDBMS. The SPARQL query engine translates a SPARQL query into a SQL one, and then the RDBMS executes the SQL query. However the RDBMS optimizers, which usually assume that columns are statistically independent, often underestimate the selectivity of conjunctive predicates and choose a bad query execution plan. It is important for query optimizers to detect correlations among properties. We propose a way of computing property correlations based on ontology itself in order to improve the execution performance of the SQL translated from SPARQL statement queries.

关键词： Ontology SPARQL SQL Property Correlation Query optimization

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