作者：
Xiao, HuiLi, QingquanSheng, QinghongWuhan Univ
Transportat Res Ctr 129 Luoyu Rd Wuhan 430079 Peoples R China Wuhan Univ
Mapping & Remote Sensing State Key Lab Informat Engn Surveying Wuhan Peoples R China Wuhan Univ
Inst Remote Sensing & Informat Engn Wuhan Peoples R China
Continuous k-nearest neighbors (CKNN) search has been in the core of spatiotemporal database research during the last decade. It is interested in continuously finding the k closest objects to a predefined query object...
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ISBN:
(纸本)9783540745808
Continuous k-nearest neighbors (CKNN) search has been in the core of spatiotemporal database research during the last decade. It is interested in continuously finding the k closest objects to a predefined query object q during a time interval. Existing methods are either computationally intensive performing repetitive queries to the database or restrictive with respect to the application settings. In this paper we develop an efficient method in order to computes CKNN queries for a query point during a specified time interval. The basic advantage of the proposed approach is that only one query is issued per time interval. The R-tree structure is used to index the static objects. An extensive performance evaluation shows that all the techniques we presented boost the query performance greatly.
This work addresses the problem of maintaining the consistency of the answers to continuous queries which are posed by the users of the moving objects databases (MOD). We propose a framework which enables detecting an...
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ISBN:
(纸本)0769519938
This work addresses the problem of maintaining the consistency of the answers to continuous queries which are posed by the users of the moving objects databases (MOD). We propose a framework which enables detecting and processing the pending queries whose answers need to be re-evaluated upon modifications to the MOD. Relevant syntactic elements of the user's queries and their semantic implications are identified, and the basic components of a system that can be used for this task are specified. We show how triggers can be used to maintain the answers to the users' queries "up to date" with respect to the modifications to the MOD and we demonstrate that our system can be implemented on top of the existing ORDBMS.
This work addresses the problem of updating moving objects databases (MOD) using real-time traffice information. The motion of the object is represented by a trajectory, which can be constructed using the available el...
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ISBN:
(纸本)0769516688
This work addresses the problem of updating moving objects databases (MOD) using real-time traffice information. The motion of the object is represented by a trajectory, which can be constructed using the available electronic maps and the information about traffic patterns. However the statistical information about traffic patterns may change due to accidents, extreme weather conditions, road work, etc... In this work we present a model for updating the trajectories of movingobjects when unexpected traffic conditions occur. Many sites provide an up-to-date information about traffic conditions on major expressways. However the unexpected traffic conditions may, affect not only the vehicles on the expressways for which an on-line monitoring is provided, but may, also have an effect on the streets near those expressways. We propose a model of this spill-over effect and we utilize it in the process of identifying the trajectories which are affected by the abnormal traffic.
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