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Wireless Sensor Networks (WSNs) are being designed to solve a gamut of interesting real-world problems. Limitations on available energy and bandwidth, message loss, high rates of node failure, and communication restrictions pose challenging requirements for these systems. Beyond these inherent limitations, both the possibility of node mobility and energy(More)
1. Medical Applications of the Future Advances in wireless sensor networking have opened up new opportunities in healthcare systems. The future will see the integration of the abundance of existing specialized medical technology with pervasive, wireless networks. They will co-exist with the installed infrastructure, augmenting data collection and real-time(More)
In sensor networks, it is crucial to design and employ energy-efficient communication protocols, since nodes are battery-powered and thus their lifetimes are limited. This paper studies data dissemination in two-tiered networks comprised of stationary sensor nodes and mobile data users who request periodic sensor data updates. We propose a protocol called(More)
The CPU schedulers in general-purpose operating systems are designed to provide fast response time for interactive applications and high throughput for batch applications. The heuristics used to achieve these goals do not lend themselves to scheduling real-time applications, nor do they meet other scheduling requirements such as coordinating scheduling(More)
—Event detection plays an important role in wireless sensor network (WSN) applications such as battlefield surveillance and habitat monitoring. However, effective approaches for specifying events in a sensor network remain a challenge. In this paper we present MEDAL, a formal event description language. MEDAL is a modified Petri net which provides a more(More)
ÐDatabase systems for real-time applications must satisfy timing constraints associated with transactions in addition to maintaining data consistency. In addition to real-time requirements, security is usually required in many applications. Multilevel security requirements introduce a new dimension to transaction processing in real-time database systems. In(More)
Acknowledgments There are three people without whom I could not have completed this dissertation. Alf Weaver saw me through the entire process with a continuous stream of valuable advice, multidimensional support, and excellent opportunities. I especially appreciated the encouragement and support he ooered during the tough times. Jorg Liebeherr spent(More)