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Diversification on big data in query processing

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Frontiers of Computer Science 2020年第4期14卷 135-154页

作者： Meifan ZHANG Hongzhi WANG Jianzhong LI Hong GAO Department of Computer Science and Technology Harbin Institute of TechnologyHarbin150001China

Recently,in the area of big data,some popular applications such as web search engines and recommendation systems,face the problem to diversify results during query *** this sense,it is both significant and essential to propose methods to deal with big data in order to increase the diversity of the result *** this paper,we firstly define the diversity of a set and the ability of an element to improve the overall *** on these definitions,we propose a diversification framework which has good performance in terms of effectiveness and ***,this framework has theoretical guarantee on probability of ***,we design implementation algorithms based on this framework for both numerical and string ***,for numerical and string data respectively,we carry out extensive experiments on real data to verify the performance of our proposed framework,and also perform scalability experiments on synthetic data.

关键词： diversification query processing big data

Improving the performance of query processing using proposed resilient distributed processing technique

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International Journal of Intelligent Computing and Cybernetics 2021年第2期14卷 158-169页

作者： C.Lakshmi K.Usha Rani Department of Computer Science Sri Padmavati Mahila VisvavidyalayamTirupatiIndia

Purpose-Resilient distributed processing technique(RDPT),in which mapper and reducer are simplified with the Spark contexts and support distributed parallel query ***/methodology/approach-The proposed work is implemented with Pig Latin with Spark contexts to develop query processing in a distributed ***-query processing in Hadoop influences the distributed processing with the MapReduce *** caters to the works on different nodes with the implementation of complex mappers and *** results are valid for some extent size of the ***/value-Pig supports the required parallel processing framework with the following constructs during the processing of queries:FOREACH;FLATTEN;COGROUP.

关键词： query processing MapReduce Scalability Resilient distributed processing Spark

Semantic-based query processing for relational data integration

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Journal of Southeast University(English Edition) 2011年第1期27卷 22-25页

作者：苗壮张亚非王进鹏陆建江周波解放军理工大学指挥自动化学院南京210007

To solve the query processing correctness problem for semantic-based relational data integration,the semantics of SAPRQL（simple protocol and RDF query language） queries is *** the course of query rewriting,all relative tables are found and decomposed into minimal connectable *** connectable units are joined according to semantic queries to produce the semantically correct query *** for query rewriting and transforming are *** complexity of the algorithms is *** the worst case,the query decomposing algorithm can be finished in O（n2） time and the query rewriting algorithm requires O（nm） *** the performance of the algorithms is verified by experiments,and experimental results show that when the length of query is less than 8,the query processing algorithms can provide satisfactory performance.

关键词： data integration relational database simple protocol and RDF query language(SPARQL) minimal connectable unit query processing

Storage optimization for query processing over data streams

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Journal of Chongqing University 2010年第2期9卷 79-92页

作者：唐向红 School of Computer Science and Technology Huazhong University of Science and Technology

A defining characteristic of continuous queries over on-line data streams,possibly bounded by sliding windows,is the potentially infinite and time-evolving nature of their inputs and *** different update patterns of continuous queries,suitable data structures bring great query processing *** this paper,we proposed a data structure suitable for weak nonmonotonic update pattern in which the lifetime of each tuple is known at generation time,but the length of lifetime is not necessarily the *** new data structure combined the ladder queue with the feature of weak non-monotonic update *** experiment results show that the new data structure performs much better than the traditional calendar queue in many cases.

关键词： calendar queue ladder queue query processing sliding windows

Peer-to-Peer Approaches to query processing in Internet-scale Networks

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Peer-to-Peer Approaches to Query Processing in Internet-scal...

Answering reachability queries with ordered label constraints over labeled graphs

2006年国际电子、工程及科学领域的分布式计算和应用学术研讨会

作者： Weining Qian Department of Computer Science and Engineering Fudan University,Shanghai 200433,China Aoying Zhou Department of Computer Science and Engineering Fudan University,Shanghai 200433,China

query processing in Internet-scale networks poses challenges such as fully decentralized processing,instability of nodes and network,and heterogeneity of *** peer-to-peer(P2P) technologies have been widely adopted in Internet-scale applications,they are far from meeting the requirements for complex query processing in efficiency. In this paper,the challenges for designing a query processing engine over P2P network are discussed first. Then,some general considerations about the P2P-based query processing system and the underlying ideas are *** on these considerations,two approaches, say,pull-based and push-based query processing,are ***,two prototyping systems,P-Terse and Sonnet,are introduced as efforts for implementing P2P query processing system with the two approaches, *** former is a peer-to-peer based text retrieval and search system,and the latter is a subscription overlay *** paper is a brief summary of the research and development work,which have been done in our research group.

关键词： Peer-to-Peer computing query processing information retrieval

来源： cnki会议评论

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Frontiers of Computer Science 2024年第1期18卷 105-117页

作者： Daoliang HE Pingpeng YUAN Hai JIN National Engineering Research Center for Big Data Technology and System Services Computing Technology and System LabCluster and Grid Computing LabSchool of Computer Science&TechnologyHuazhong University of Science and TechnologyWuhan 430074China

Reachability query plays a vital role in many graph analysis *** researches proposed many methods to efficiently answer reachability queries between vertex *** many real graphs are labeled graph,it highly demands Label-Constrained Reachability(LCR)query inwhich constraint includes a set of labels besides vertex *** researches proposed several methods for answering some LCR queries which require appearance of some labels specified in constraints in the *** that constraint may be a label set,query constraint may be ordered labels,namely OLCR(Ordered-Label-Constrained Reachability)queries which retrieve paths matching a sequence of ***,no solutions are available for ***,we propose DHL,a novel bloom filter based indexing technique for answering OLCR *** can be used to check reachability between vertex *** the answers are not no,then constrained DFS is ***,we employ DHL followed by performing constrained DFS to answer OLCR *** show that DHL has a bounded false positive rate,and it's powerful in saving indexing time and *** experiments on 10 real-life graphs and 12 synthetic graphs demonstrate that DHL achieves about 4.8-22.5 times smaller index space and 4.6-114 times less index construction time than two state-of-art techniques for LCR queries,while achieving comparable query response *** results also show that our algorithm can answer OLCR queries effectively.

关键词： graph ordered-label-constrained reachability partial index bloom filter query processing

processing Constrained K Closest Pairs query in Spatial Databases

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Wuhan University Journal of Natural Sciences 2006年第3期11卷 543-546页

作者： LIU Xiaofeng LIU Yunsheng XIAO Yingyuan College of Computer Science and Technology Huazhong University of Science and Technology Wuhan 430074Hubei China

In this paper, constrained K closest pairs query is introduced, wbich retrieves the K closest pairs satisfying the given spatial constraint from two datasets. For data sets indexed by R trees in spatial databases, three algorithms are presented for answering this kind of query. Among of them, two-phase Range＋Join and Join＋Range algorithms adopt the strategy that changes the execution order of range and closest pairs queries, and constrained heap-based algorithm utilizes extended distance functions to prune search space and minimize the pruning distance. Experimental results show that constrained heap-base algorithm has better applicability and performance than two-phase algorithms.

关键词： spatial databases query processing R-tree closest pairs query constrained closest pairs query

System Ⅱ:A Native RDF Repository Based on the Hypergraph Representation for RDF Data Model

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Journal of Computer Science & Technology 2009年第4期24卷 652-664页

作者：吴刚李涓子胡建强王克宏 School of Computer Science and Engineering Southeast University CCF ACM Department of Computer Science and Technology Tsinghua University

RDF is the data interchange layer for the Semantic Web. an RDF repository should provide not only the necessary scalability In order to manage the increasing amount of RDF data, and efficiency, but also sufficient inference capabilities. Though existing RDF repositories have made progress towards these goals, there is still ample space for improving the overall performance. In this paper, we propose a native RDF repository, System H, to pursue a better tradeoff among system scalability, query efficiency, and inference capabilities. System II takes a hypergraph representation for RDF as the data model for its persistent storage, which effectively avoids the costs of data model transformation when accessing RDF data. Based on this native storage scheme, a set of efficient semantic query processing techniques are designed. First, several indices are built to accelerate RDF data access including a value index, a labeling scheme for transitive closure computation, and three triple indices. Second, we propose a hybrid inference strategy under the pD＊ semantics to support inference for OWL-Lite with a relatively low computational complexity. Finally, we extend the SPARQL algebra to explicitly express inference semantics in logical query plan by defining some new algebra operators. In addition, MD5 hash value of URI and schema level cache are introduced as practical implementation techniques. The results of performance evaluation on the LUBM benchmark and a real data set show that System Ⅱ has a better combined metric value than other comparable systems.

关键词： RDF data management query processing index

Incomplete data management： a survey

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Frontiers of Computer Science 2018年第1期12卷 4-25页

作者： Xiaoye MIAO Yunjun GAO Su GUO Wanqi LIU College of Computer Science Zhejiang University Hangzhou 310027 China The Key Lab of Big Data Intelligent Computing of Zhejiang Province Zhejiang University Hangzhou 310027 China

Incomplete data accompanies our life processes and covers almost all fields of scientific studies, as a result of delivery failure, no power of battery, accidental loss, etc. However, how to model, index, and query incomplete data in- curs big challenges. For example, the queries struggling with incomplete data usually have dissatisfying query results due to the improper incompleteness handling methods. In this pa- per, we systematically review the management of incomplete data, including modelling, indexing, querying, and handling methods in terms of incomplete data. We also overview sev- eral application scenarios of incomplete data, and summa- rize the existing systems related to incomplete data. It is our hope that this survey could provide insights to the database community on how incomplete data is managed, and inspire database researchers to develop more advanced processing techniques and tools to cope with the issues resulting from incomplete data in the real world.

关键词： incomplete data query processing indexing,application system