Location-Clustering Techniques For Wlan Location Determination Systems

AbstractWe present location clustering as a technique to significantly reduce the computational requirements of WLAN location determination systems. We provide two algorithms, joint clustering and incremental triangulation, and describe their trade-offs between computational cost and location determination accuracy. Both techniques reduce computational cost by more than an order of magnitude, allowing noncentralized implementation on mobile clients and enabling new context-aware applications. We present a performance comparison of the two techniques in an actual testbed implementation.Key Words: Energy efficient WLAN location determinationlocation-aware systemsradio map locations clusteringuser positioningwireless LAN Additional informationNotes on contributorsM. YoussefMoustafa Youssef is a faculty research associate in the Department of Computer Science at the University of Maryland at College Park. He received his B.Sc. and M.Sc. in computer science from Alexandria University, Egypt, in 1997 and 1999 respectively, and Ph.D. in computer science from University of Maryland in 2004. His research interests include location determination technologies, pervasive computing, energy-aware computing, sensor net-works, and protocol modelling. Dr. Moustafa is a life fellow of the Egyptian Society for the Talented and an elected member of the honour society Phi Kappa Phi, among others. He is a member of various professional societies such as IEEE, IEEE Computer Society, IEEE Communication Society, and ACM Sigmobile. Dr. Moustafa is the recipient of the 2003 University of Maryland Invention of the Year award for his Horus work.A. AgrawalaAshok Agrawala is a faculty re-search associate at the University of Maryland at College Park. In 2001 he started the Maryland In-formation and Network Dynamics (MIND) Lab, which carries out research and development activi-ties in partnership with the industry. He received his B.E. degree in 1963 and an M.E. in 1965 from the I.I.Sc, Bangalore; and a Master of Arts and his Ph.D. in ap-plied mathematics from Harvard University in 1970. Prof. Agrawala is the author of seven books, six patents (awarded or pending), and over 240 papers and is a recognized authority in the research into and use of time management in real-time processing and clock synchronization applications. He has developed a few location determination techniques and several other innovative technologies for systems and networks, which are in different stages of deployment. Prof. Agrawala is a fellow of the IEEE and senior member of the ACM.