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2DCMA： An Effective Maintenance Algorithm of Materialized Views in Peer data Management Systems

Journal of Computer Science & Technology 2006年第4期21卷 503-512页

作者：覃飙王珊杜小勇 School of Information Renmin University of China Beijing 100872 P.R. China Key Laboratory of Data Engineering and Knowledge Engineering Ministry of Education Beijing 100872 P.R. China

Update management is very important for data integration systems. So update management in peer data management systems （PDMSs） is a hot research area. This paper researches on view maintenance in PDMSs. First, the definition of view is extended and the peer view, local view and global view are proposed according to the requirements of applications. There are two main factors to influence materialized views in PDMSs. One is that schema mappings between peers are changed, and the other is that peers update their data. Based on the requirements, this paper proposes an algorithm called 2DCMA, which includes two sub-algorithms： data and definition consistency maintenance algorithm% to effectively maintain views. For data consistency maintenance, Mork＇s rules are extended for governing the use of updategrams and boosters. The new rule system can be used to optimize the execution plan. And are extended for the data consistency maintenance algorithm is based on the new rule system. Furthermore, an ECA rule is adopted for definition consistency maintenance. Finally, extensive simulation experiments are conducted in SPDMS. The simulation results show that the 2DCMA algorithm has better performance than that of Mork＇s when maintaining data consistency. And the 2DCMA algorithm has better performance than that of centralized view maintenance algorithm when maintaining definition consistency.

关键词： view maintenance peer data management system schema mapping ECA rule

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Maintaining materialized relations incrementally to improve performance of ontology query

Maintaining materialized relations incrementally to improve ...

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7th International Conference on Web-Age Information Management Workshops, WAIM 2006

作者： Li, Man Du, Xiaoyong Wang, Shan School of Information Renmin University of China China Key Laboratory of Data Engineering and Knowledge Engineering MOE 100872 Beijing China

ISBN: (纸本)0769527051

For ontology-based applications, the efficiency of ontology query is vital. Different from existing approaches, the paper improves performance of ontology query by materializing some derived relations. Experimental results show that the integrated performance of ontology query can be improved greatly by maintaining materialized relations and the materialized relations technique has good scalability. Here the challenge is how to maintain the materialized relations incrementally with the update of ontologies. Because transitive relations are in common use in ontology, the paper proposes a novel algorithm for maintaining transitive materialized relations incrementally based on a special weighted materialized relation transitive graph, which can solve the coexistence problem of multiple derived paths better and proves the correctness of the algorithm. © 2006 IEEE.

关键词： Ontology

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NUITS: A Novel User Interface for Efficient Keyword Search over databases

NUITS: A Novel User Interface for Efficient Keyword Search o...

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32nd International Conference on Very Large data Bases, VLDB 2006

作者： Wang, Shan Peng, Zhaohui Zhang, Jun Qin, Lu Wang, Sheng Yu, Jeffrey Xu Ding, Bolin School of Information Renmin Univ. of China Key Laboratory of Data Engineering and Knowledge Engineering MOE of China Beijing China Department of Systems Engineering and Engineering Management The Chinese Univ. of Hong Kong Hong Kong Hong Kong

ISBN: (纸本)1595933859

The integration of database and information retrieval techniques provides users with a wide range of high quality services. We present a prototype system, called NUITS, for efficiently processing keyword queries on top of a relational database. Our NUITS allows users to issue simple keyword queries as well as advanced keyword queries with conditions. The efficiency of keyword query processing and the user-friendly result display will also be addressed in this paper. Copyright 2006 VLDB Endowment, ACM

关键词： Query processing

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An Economic Semantic Web Platform

An Economic Semantic Web Platform

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International Conference on Grid and Cooperative Computing Workshops (GCCW)

作者： Xiaoyong Du He Hu Man Li Wenjuan Wu Guo Qin Key Laboratory of Data Engineering and Knowledge Engineering MOE School of Information Renmin University of China Beijing China

The paper describes an ongoing project which implements a subject-oriented semantic Web platform at Renmin Univ. of China. The economic semantic Web platform (ESWP) contains three components: collaborative ontology developing environment and repository system (CODERS); economic ontology annotation Web services (ConAnnotator); economic ontology and annotated resources. We describe each of these components in detail and illustrate some use cases of the ESWP

关键词： Semantic Web Ontologies Environmental economics Web services Collaboration Humans Software agents Application software Helium Laboratories

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Reinforcement Learning for Query-Oriented Routing Indices in Unstructured Peer-to-Peer Networks

Reinforcement Learning for Query-Oriented Routing Indices in...

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International Conference on Peer-to-Peer Computing

作者： Cong Shi Shicong Meng Yuanjie Liu Dingyi Han Yong Yu Apex Data and Knowledge Management Laboratory Department of Computer Science and Engineering Shanghai Jiaotong University Shanghai China

The idea of building query-oriented routing indices has changed the way of improving routing efficiency from the basis as it can learn the content distribution during the query routing process. It gradually improves routing efficiency with no excessive network overhead of the routing index construction and maintenance. However, the previously proposed mechanism is not practically effective due to the slow improvement of routing efficiency. In this paper, we propose a novel mechanism for query-oriented routing indices which quickly achieves high routing efficiency at low cost. The maintenance method employs reinforcement learning to utilize mass peer behaviors to construct and maintain routing indices. It explicitly uses the expected value of returned content number to depict the content distribution, which helps quickly approximate the real distribution. Meanwhile, the routing method is to retrieve as many contents as possible. It also helps speed up the learning process further. The experimental evaluation shows that the mechanism has high routing efficiency, quick learning ability and satisfactory performance under churn

关键词： Learning Routing Peer to peer computing Query processing Buildings knowledge management Computer science data engineering knowledge engineering Costs

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Mining and Predicting Duplication over Peer-to-Peer Query Streams

Mining and Predicting Duplication over Peer-to-Peer Query St...

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IEEE International Conference on data Mining Workshops (ICDM Workshops)

作者： Shicong Meng Yifeng Shao Cong Shi Dingyi Han Yong Yu APEX Data and Knowledge Management Laboratory Department of Computer Science and Engineering Shanghai Jiaotong University Shanghai China

Many previous works of data mining user queries in peer-to-peer systems focused their attention on the distribution of query contents. However, few has been done towards a better understanding of the time series distribution of these queries, which is vital for system performance. To remedy this situation, this paper mines query steams by using automatic time series analysis to evaluate different linear models (Box-Jenkins models and some simple windowed-mean models) for predicting the number of duplicated queries from 10 minutes to 2 hours into the future. Both the predictive power and the computational costs of these models are evaluated over 318,942,450 real world Gnutella queries collected over 3 months. We find the number of duplicated queries is consistently predictable. Simple, practical models like AR perform well on prediction

关键词： Peer to peer computing Predictive models Power system modeling data mining System performance Crawlers Time series analysis Computational efficiency Load management knowledge management

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Cuckoo Ring: BalancingWorkload for Locality Sensitive Hash

Cuckoo Ring: BalancingWorkload for Locality Sensitive Hash

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International Conference on Peer-to-Peer Computing

作者： Dingyi Han Ting Shen Shicong Meng Yong Yu Apex Data & Knowledge Management Laboratory Department of Computer Science & Engineering Shanghai Jiaotong University Shanghai China

Locality sensitive hash (LSH) is widely used in peer-to-peer (P2P) systems. Although it can support range or similarity queries, it breaks the load balance mechanism of traditional distributed hash table (DHT) based system by replacing consistent hash with LSH. To solve the imbalance problem, current systems either weaken the locality preserve ability from similarity preserved to order preserved or adopt load aware peer join mechanism. The first method does not support similarity query as it loses the similarity information and the second method is greatly affected by the dynamic nature of P2P networks. In this paper, we propose a novel system, cuckoo ring, which can preserve similarity information while load balanced. It does not guide the newly joining peer to the hot areas but move the items in the hot areas to cold areas so that the short life time peers are distributed uniformly across the network instead of being guided to the hot areas. Compared to traditional DHT systems, cuckoo ring only maintains a little more information about the global light load peers and the moved indexed items

关键词： Indexing Load management knowledge management Computer science data engineering knowledge engineering Nearest neighbor searches Q measurement

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NUITS: a novel user interface for efficient keyword search over databases 06

NUITS: a novel user interface for efficient keyword search o...

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Proceedings of the 32nd international conference on Very large data bases

作者： Shan Wang Zhaohui Peng Jun Zhang Lu Qin Sheng Wang Jeffrey Xu Yu Bolin Ding School of Information Renmin Univ. of China Key Laboratory of Data Engineering and Knowledge Engineering MOE of China Beijing China Department of Systems Engineering and Engineering Management The Chinese Univ. of Hong Kong Hong Kong China

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Survey on ontology learning research

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Ruan Jian Xue Bao/Journal of Software 2006年第9期17卷 1837-1847页

作者： Du, Xiao-Yong Li, Man Wang, Shan School of Information Renmin University of China Beijing 100872 China Key Laboratory of Data Engineering and Knowledge Engineering Beijing 100872 China

Recently, ontology learning is emerging as a new hotspot of research in computer science. In this paper the issue of ontology learning is divided into nine sub-issues according to the structured degree (structured, semi-structured, non-structured) of source data and learning objects (concept, relation, axiom) of ontology. The characteristics, major approaches and the latest research progress of the nine sub-issues are summarized. Based on the analysis framework proposed in the paper, existing ontology learning tools are introduced and compared. The problems of current research are discussed, and finally the future directions are pointed out.

关键词： Computer science

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Embodiment and interaction guidelines for designing credible, trustworthy embodied conversational agents

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4th International Workshop on Intelligent Virtual Agents, IVA 2003

作者： Cowell, Andrew J. Stanney, Kay M. Data and Knowledge Engineering Pacific Northwest National Laboratory RichlandWA99352 United States Department of Industrial Engineering and Management Systems University of Central Florida OrlandoFL32816 United States

ISBN: (纸本)3540200037

This paper discusses our recent studies on Embodied Conversational Agent (ECA) design strategies to encourage credible and trustworthy dialogue. We approach the problem from two specific directions: the embodiment that the character. wears. during its interchange with the user, and the method of interaction used by the ECA to engage the user. Our results indicate that while users generally prefer to interact with a youthful character matching their ethnicity, no significant preferences were indicated for character gender. For interaction, our results indicated that a character that portrayed trusting nonverbal behaviors was rated as being significantly more credible than a character portraying no nonverbal behavior, or one that portrayed non-trusting behaviors. Other interesting results from this work are also discussed. © Springer-Verlag Berlin Heidelberg 2003.

关键词： Interactive computer systems

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