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讲座内容: 时间：2009年12月25日周五 上午 10：00 ~ 12：00 地点：信息楼四楼学术报告厅 Title: Continuous Intersection Joins Over Moving Objects 内容：澳大利亚张瑞博士的学术报告，大约1个小时，然后请同学们踊跃提问参与。同时张博士会介绍一下澳大利亚的留学相关政策，欢迎对出国留学感兴趣的同学参与。 张瑞博士是澳大利亚墨尔本大学的讲师，在新加坡国立大学获博士学位。他的主要研究方向包括空间数据库，数据流管理，序列数据管理和云计算。他已在顶级的会议和期刊，包括VLDB Journal，TKDE，SIGMOD，ICDE等发表论文二十多篇。非常欢迎对以上课题感兴趣的各位老师与张博士沟通交流，也鼓励大家合作共同做一些前沿的研究。张博士的办公室在信息楼419房间。欢迎相关的老师和同学们到他的办公室交流和讨论！ Abstract: The continuous intersection join query is computationally expensive yet important for various applications on moving objects. No previous study has specifically addressed this query type. We can adopt a naive algorithm or extend an existing technique (TP-Join) to process the query. However, they compute the answer for either too long or too short a time interval, which results in either a very large computation cost per object update or too frequent answer updates, respectively. This motivates us to optimize the query processing in the time dimension. In this study, we achieve this optimization by introducing the new concept of time-constrained (TC) processing. Further, TC processing enables a set of effective improvement techniques on traditional intersection join algorithms. With a thorough experimental study, we show that our algorithm outperforms the best adapted existing solution by several orders of magnitude. Bio: Dr Rui Zhang is a lecturer at the Department of Computer Science and Software Engineering of the University of Melbourne. He got his PhD from National University of Singapore. His research interests include indexing and query processing, Spatial and temporal data management, sequence data management, data streams, and cloud computing. He has published widely in top database conferences and serve as PC members on many of such conferences. Please see his website for more information: http://www.csse.unimelb.edu.au/~rui/