CPSWEEK

This volume contains the Proceedings of the Fourth International Symposium on Information Processing in Sensor Networks (IPSN'05). The symposium was held at University of California, Los Angeles, California on April 24-27, 2005. This symposium continues the tradition of the first three IPSN symposia held at Xerox PARC, Palo Alto in 2001 and 2003, and at University of California, Berkeley in 2004.Sensor network draws upon diverse disciplines in computer science, computer engineering, signal processing, image processing, information and coding theory, networking and protocols, distributed algorithms, sensor technology, wireless communication, machine learning, detection, estimation, tracking, embedded systems, software/firmware/hardware architecture, database, and information management. The area of sensor networking has experienced explosive growth in recent years partly due to rapid advances in MEMS microsensors, ad hoc networking, and embedded processing. Sensor networking has found diverse applications in commercial, industrial, scientific, environmental, and military monitoring and control.While the first three IPSN symposia were held in two days, IPSN'05 was held over three days, with the first two days featuring the system-oriented aspects of sensor networking, with the third day including a track on platform tools and design methods for networked embedded sensors (SPOTS). IPSN'05 was comprehensive and covered the full spectrum of the theory, engineering practice and design, and application of sensor networking.IPSN is sponsored by the IEEE Signal Processing Society and the Association for Computing Machinery (ACM).