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Article: An efficient location update mechanism for continuous queries over moving objects

TitleAn efficient location update mechanism for continuous queries over moving objects
Authors
KeywordsContinuous queries
Moving objects
Temporal correctness
Update generation schemes
Issue Date2007
PublisherPergamon. The Journal's web site is located at http://www.elsevier.com/locate/is
Citation
Information Systems, 2007, v. 32 n. 4, p. 593-620 How to Cite?
AbstractIn a moving-object database system that supports continuous queries (CQ), an important problem is to keep the location data consistent with the actual locations of the entities being monitored, in order to produce correct query results. This goal is often difficult to achieve due to limited network resources. However, if an object is not required by any query, its value need not be refreshed. Based on this observation, we redefine the notion of temporal consistency of data items with respect to the query result, where only data items that are relevant to the CQs need to be fresh. To exploit this correctness definition, we develop an adaptive time-based update technique called query-result update (QRU). The advantage of this technique is that it identifies objects with different levels of significance to the correctness of query results. Locations of objects that have more impact to the query result are acquired more frequently than the ones that do not. To achieve this objective, queries are classified into rank-based (i.e., ranks of objects are critical to query results) and non-rank-based. For each query class, QRU decides the time instant that an object should send a location update based on the predicted impact of the object to the query result. Moreover, the location update frequency of each object is continuously adjusted in order to adapt to the accuracy of the prediction model used. We evaluate the effectiveness of QRU by simulating execution of CQs over synthetic and real data sets. We also compare QRU experimentally with existing location update policies, namely the distance-based method, the time-based method, the speed dead-reckoning method, as well as the safe region strategy. © 2006 Elsevier B.V. All rights reserved.
Persistent Identifierhttp://hdl.handle.net/10722/129990
ISSN
2023 Impact Factor: 3.0
2023 SCImago Journal Rankings: 1.201
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorCheng, Ren_HK
dc.contributor.authorLam, KYen_HK
dc.contributor.authorPrabhakar, Sen_HK
dc.contributor.authorLiang, Ben_HK
dc.date.accessioned2010-12-23T08:45:11Z-
dc.date.available2010-12-23T08:45:11Z-
dc.date.issued2007en_HK
dc.identifier.citationInformation Systems, 2007, v. 32 n. 4, p. 593-620en_HK
dc.identifier.issn0306-4379en_HK
dc.identifier.urihttp://hdl.handle.net/10722/129990-
dc.description.abstractIn a moving-object database system that supports continuous queries (CQ), an important problem is to keep the location data consistent with the actual locations of the entities being monitored, in order to produce correct query results. This goal is often difficult to achieve due to limited network resources. However, if an object is not required by any query, its value need not be refreshed. Based on this observation, we redefine the notion of temporal consistency of data items with respect to the query result, where only data items that are relevant to the CQs need to be fresh. To exploit this correctness definition, we develop an adaptive time-based update technique called query-result update (QRU). The advantage of this technique is that it identifies objects with different levels of significance to the correctness of query results. Locations of objects that have more impact to the query result are acquired more frequently than the ones that do not. To achieve this objective, queries are classified into rank-based (i.e., ranks of objects are critical to query results) and non-rank-based. For each query class, QRU decides the time instant that an object should send a location update based on the predicted impact of the object to the query result. Moreover, the location update frequency of each object is continuously adjusted in order to adapt to the accuracy of the prediction model used. We evaluate the effectiveness of QRU by simulating execution of CQs over synthetic and real data sets. We also compare QRU experimentally with existing location update policies, namely the distance-based method, the time-based method, the speed dead-reckoning method, as well as the safe region strategy. © 2006 Elsevier B.V. All rights reserved.en_HK
dc.languageengen_US
dc.publisherPergamon. The Journal's web site is located at http://www.elsevier.com/locate/isen_HK
dc.relation.ispartofInformation Systemsen_HK
dc.rightsAppropriate Bibliographic Citation:Authors posting Accepted Author Manuscript online should later add a citation for the Published Journal Article indicating that the Article was subsequently published, and may mention the journal title provided that they add the following text at the beginning of the document: “NOTICE: this is the author’s version of a work that was accepted for publication in <Journal title>. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in PUBLICATION, [VOL#, ISSUE#, (DATE)] DOI#”-
dc.subjectContinuous queriesen_HK
dc.subjectMoving objectsen_HK
dc.subjectTemporal correctnessen_HK
dc.subjectUpdate generation schemesen_HK
dc.titleAn efficient location update mechanism for continuous queries over moving objectsen_HK
dc.typeArticleen_HK
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=0306-4379&volume=32&issue=4&spage=593&epage=620&date=2007&atitle=An+Efficient+Location+Update+Mechanism+for+Continuous+Queries+over+Moving+Objects-
dc.identifier.emailCheng, R:ckcheng@cs.hku.hken_HK
dc.identifier.authorityCheng, R=rp00074en_HK
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.doi10.1016/j.is.2006.03.002en_HK
dc.identifier.scopuseid_2-s2.0-33846908144en_HK
dc.identifier.hkuros176452en_US
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-33846908144&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume32en_HK
dc.identifier.issue4en_HK
dc.identifier.spage593en_HK
dc.identifier.epage620en_HK
dc.identifier.isiWOS:000244992600005-
dc.publisher.placeUnited Kingdomen_HK
dc.identifier.scopusauthoridCheng, R=7201955416en_HK
dc.identifier.scopusauthoridLam, KY=7403656886en_HK
dc.identifier.scopusauthoridPrabhakar, S=7101672592en_HK
dc.identifier.scopusauthoridLiang, B=8641604300en_HK
dc.identifier.issnl0306-4379-

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