CS Colloquium Series @ UCY
Department of Computer Science - University of Cyprus
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Colloquium Coordinator: Demetris Zeinalipour
Colloquium: Proportionality in Spatial Keyword Search, Dr. George Fakas (Uppsala University, Sweden), Friday, February 4, 2022, 16:00-17:00 EET.
The Department of Computer Science at the University of Cyprus cordially invites you to the Colloquium entitled:
Proportionality in Spatial Keyword Search
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Speaker: Dr. George Fakas |
Abstract:
More often than not, spatial objects are associated with some context, in the form of text, descriptive tags (e.g. points of interest, flickr photos), or linked entities in semantic graphs (e.g. Yago2, DBpedia). Hence, location-based retrieval should be extended to consider not only the locations but also the context of the objects, especially when the retrieved objects are too many and the query result is overwhelming. In this paper, we study the problem of selecting a subset of the query result, which is the most representative. We argue that objects with similar context and nearby locations should proportionally be represented in the selection. Proportionality dictates the pairwise comparison of all retrieved objects and hence bears a high cost. We propose novel algorithms which greatly reduce the cost of proportional object selection in practice. Extensive empirical studies on real datasets show that our algorithms are effective and efficient. A user evaluation verifies that proportional selection is more preferable than random selection and selection based on object diversification.
Short Bio:
George Fakas is an Associate Professor (Docent) at the Department of Information Technology, Uppsala University. He is currently leading the Uppsala DataBase Laboratory (UDBL) within the Department of Information Technology. Before joining Uppsala University, he worked as a Research Fellow at the Hong Kong University of Science and Technology (with Prof. Dimitris Papadias), Hong Kong University (with Prof. Nikos Mamoulis), EPFL (Lausanne, Switzerland), UMIST (Manchester, UK), University of Cyprus (Cyprus). He also worked as a Senior Lecturer at Manchester Metropolitan University (UK). He has published papers in the most influential conferences and journals of data management, including SIGMOD, PVLDB, VLDB Journal, IEEE TKDE, DKE, etc. He obtained his Ph.D. in 1998, his M.Phil. in 1996 and his B.Sc. in Computation in 1995; all from the Department of Computation, UMIST, Manchester, UK. His research interests include big data, keyword search and ranking on (semi) structure data and (attributed) graphs. web search, online (geo) social networks.
