Date of Award


Document Type

Doctoral Thesis

Degree Name

Doctor of Philosophy


Electronic Engineering

First Advisor

Dr. Dirk Pesch


The application space of wireless sensor networks has evolved considerably from their initial role as an efficient data gathering system. Modern wireless sensor networks are expected to be dynamic, powerful. reliable and flexible, while continuing to operate efficiently and autonomously. The supporting software' systems have not kept pace with this development, and currently limits the deployment of complex and robust applications. Mobile software agents present a powerful approach to application design, however no existing middleware for wireless sensor networks supports native mobile software agents.

The main contribution of the work presented in this thesis is the development and evaluation of a middleware supporting powerful mobile software agents for wireless sensor networks. A hybrid memory allocation strategy is developed to encapsulate the mobile agent, a code caching strategy is used to reduce unnecessary transmission and directed movement is used to simplify agents and to allow attribute-based movement and operation. These improvements act to reduce the overall energy consumption of the agent system.

A number of application scenarios are used to evaluate the system performance. The primary defining characteristic of wireless sensor network systems is their low energy consumption, and the proposed system demonstrates lower-power operation than existing mobile agent systems in environments where complex, mobile, in-network processing, control or actuation are required, particularly when code caching can be exploited. This is best demonstrated by the reliable control system, that is capable of dynamically adapting to a changing topology, reliably recovering from node and communication failures while continuing to provide application functionality in unaffected systems, while still leaving enough resource free to allow independent applications to run on the wireless sensor network.

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