ABSTRACT
We present our prototype system, OMCAT, which optimizes the reevaluation of a set of pending continuous spatio-temporal queries on trajectory data, when some of the trajectories are affected by traffic abnormalities reported. The key observation that motivates OMCAT is that an abnormality in a given geographical region may cause changes to the answers of queries pertaining to future portions of affected trajectories. We investigate the sources of context-switching costs at various levels and propose solutions that utilize the correlation of several context dimensions to orchestrate the reevaluation of the queries. OMCAT, fully implemented on top of an existing Object Relational Database Management System - Oracle 9i, demonstrates that our techniques can substantially reduce the response time during query answer update.
- OMCAT project homepage. http://www.eecs.northwestern.edu/¿hdi117/omcat.htm.Google Scholar
- Oracle 9i. http://www.oracle.com/technology/products/oracle9i.Google Scholar
- Ralf Hartmut Güting and Markus Schneider. Moving Object Databases. Morgan Kaufmann Publishers, CA, 2005.Google Scholar
- Glenn S. Iwerks, Hanan Samet, and Ken Smith. Continuous k-nearest neighbor queries for continuously moving points with updates. In VLDB, pages 512--523, 2003. Google ScholarDigital Library
- Mohamed F. Mokbel, Xiaopeng Xiong, and Walid G. Aref. SINA: Scalable incremental processing of continuous queries in spatio-temporal databases. In SIGMOD Conference, pages 623--634, 2004. Google ScholarDigital Library
- Jochen Schiller and Agnès Voisard. Location-Based Services. Morgan Kaufmann Publishers, CA, 2004. Google ScholarDigital Library
- A. Prasad Sistla, Ouri Wolfson, Sam Chamberlain, and Son Dao. Modeling and querying moving objects. In ICDE, pages 422--432, 1997. Google ScholarDigital Library
- Ouri Wolfson, Hu Cao, Hai Lin, Goce Trajcevski, Fengli Zhang, and Naphtali Rishe. Management of dynamic location information in domino. In EDBT, pages 769--771, 2002. Google ScholarDigital Library
Index Terms
- OMCAT: optimal maintenance of continuous queries' answers for trajectories
Recommendations
Triggers and Continuous Queries in Moving Objects Database
DEXA '03: Proceedings of the 14th International Workshop on Database and Expert Systems ApplicationsThis work addresses the problem of maintaining theconsistency of the answers to continuous queries whichare posed by the users of the Moving Objects Databases(MOD).We propose a framework which enables detectingand processing the pending queries whose ...
Answer-pairs and processing of continuous nearest-neighbor queries
FOMC '11: Proceedings of the 7th ACM ACM SIGACT/SIGMOBILE International Workshop on Foundations of Mobile ComputingWe consider the problem of evaluating the continuous query of finding the k nearest objects with respect to a given moving point-object Oq among a set of n moving point-objects. The query returns a sequence of answer-pairs, namely pairs of the form (I, ...
Efficient Maintenance of Continuous Queries for Trajectories
We address the problem of optimizing the maintenance of continuous queries in Moving Objects Databases, when a set of pending continuous queries need to be reevaluated as a result of bulk updates to the trajectories of moving objects. Such bulk updates ...
Comments