Pervasive Sensing and Computing (PSC) will penetrate many walks of human life transforming the way we instrument and control our surroundings. This talk will review recent technology developments in the area of integrated pervasive sensing and computing, and address research challenges ahead. Progress and trends in defense and commercial applications will be presented. The talk will cover recent advances in micro-sensor technology including hardware platforms, networking and collaborative computing methods, as well as middleware and PSC applications. Key accomplishments from related DARPA programs will be presented. Challenges in transforming sensor data to knowledge supporting decision making will be covered. Potential approaches to dramatically reduce device costs and form factor through chip-scale integration of processing, communications, and micro and nano-sensors (MEMS and NEMS) will be discussed. Algorithmic and software challenges for building high-functionality context-aware systems that are also robust, reliable, and secure will be presented. Potential directions in application of cognitive information processing techniques including machine reasoning and learning to achieve rapid adaptation (of PSC systems) to changes in contexts and environments will be discussed. The talk will also present applications, near and far-term, along with associated research challenges.

Wireless microsensor networks have been identified as one of the most important technologies for the 21st century. This paper traces the history of research in sensor networks over the past three decades, including two important programs of the Defense Advanced Research Projects Agency (DARPA) spanning this period: the Distributed Sensor Networks (DSN) and the Sensor Information Technology (SensIT) programs. Technology trends that impact the development of sensor networks are reviewed, and new applications such as infrastructure security, habitat monitoring, and traffic control are presented. Technical challenges in sensor network development include network discovery, control and routing, collaborative signal and information processing, tasking and querying, and security. The paper concludes by presenting some recent research results in sensor network algorithms, including localized algorithms and directed diffusion, distributed tracking in wireless ad hoc networks, and distributed classification using local agents.

A dynamic programming formulation is used to obtain an optimal strategy for the handoff problem in cellular radio systems. The formulation includes the modeling of the underlying randomness in received signal strengths as well as the movements of the mobile. The cost function is designed such that there is a cost associated with switching and a reward for improving the quality of the call. The optimum decision is characterized by a threshold on the difference between the measured power that the mobile receives from the base stations. Also we study the problem of choosing the "best" fixed threshold that minimizes the cost function. The performance of the optimal and suboptimal strategies are compared.>