Title: Processing Spatio-Temporal Queries for Uncertain Trajectories
Time: 2pm on June 10, 2013
Space: ECS 212
ABSTRACT: The ( location, time) data capturing the motion of moving objects is subject to uncertainty due to a number of reasons, such as the imprecision of GPS devices and the fact that we cannot record this data for every time-instant. As a consequence of uncertainty the results of continuous queries become probabilistic in nature, i.e., an objects or trajectory is associated with a qualification probability that indicates how likely it is the answer of the query. We discuss first different models for modeling uncertainty of moving objects in free space and on road networks. Next we formalize two of the most popular types of continuous queries, range queries and nearest neighbor (NN) queries, under the free space and road network models. Next , we elaborate on a methodology for processing NN-queries for the sheared cylinders model used to represent time-parameterized motion in free space. We demonstrate that by using the convolution technique from probability theory we can transform the original problem into a much simpler one, where the query trajectory becomes crisp.
BIOGRAPHY: Peter Scheuermann is a Professor of Electrical Engineering and Computer Science at Northwestern University. He has held visiting professor positions with the Free University of Amsterdam, the Technical University of Berlin, the Swiss Federal Institute of Technology, Zurich and University of Melbourne. During 1997-1998 he served as Program Director for Operating Systems at the NSF. Dr. Scheuermann has served on the editorial board of the Communications of ACM, The VLDB Journal, IEEE Transactions on Knowledge and Data Engineering and is currently an associate editor of Data and Knowledge Engineering, Wireless Network and the new ACM Trans. on Spatial Algorithms and Systems. Among his professional activities, he has served as General chair of the ACM-SIGMOD Conference in 1988, General Chair of the ER ‘2003 Conference and more recently as Program Co-Chair of the ACM-SIGPATIAL conference in 2009. He was a member of the ACM-SIGMOD advisory board, and prior to this he chaired the ACM-SIGMOD awards committee His research interests are in spatio-temporal databases, mobile computing, sensor networks and data mining. He has published more than 140 journal and conference papers. His research has been funded by NSF, NASA, HP, Northrop Grumman, and BEA, among others. Peter Scheuermann is a Fellow of IEEE and AAAS (American Association for the Advancement of Science).