an approach which reconciles portability and efficiency, and preserves the ability to dynamically load bytecode. We have designed and implemented an efficient environment for the execution of Java programs, named Harissa. Harissa permits the mixing of compiled and interpreted methods. Harissa's compiler

This paper describes Hyperion, an environment for executing Java programs on clusters of computers. To provide high performance, the environment compiles Java bytecode to native code and supports the concurrent execution of Java threads on multiple nodes of a cluster. The implementation uses the PM

the flexibility of a general purpose microprocessor to run legacy code and lightweight Java methods, with the high performance of a specialized execution engine on speed-critical bytecode. This work proposes and analyzes a microprocessor with FPGA coprocessor architecture with efficient shared

marries the flexibility of a general-purpose microprocessor to run legacy code and lightweight Java methods, with the high performance of a specialised execution engine on speed-critical bytecode. This work proposes and analyses a microprocessor with FPGA coprocessor architecture with efficient shared

with diverse computational resources and sensors. A salient feature of Servilla is its support for dynamic discovery and binding to local and remote services, which enables flexible and energy-efficient in-network collaboration among heterogeneous devices. Furthermore, Servilla provides a modular middleware

First, I would like to thank to Dimka Karastoyanova and Mariano Cilia for all the fruitful discussions, their guidance and support through the course of this project. Thanks also to Prof. Alejandro Buchmann who sponsored my stay at Technische Universität Darmstadt during the spring of 2004. The special thanks go to my advisor, Mariano Cilia, who has made all this possible. Finally, I’d like to thank to my family for all these years of support.

Abstract: Mobile ad hoc networks (MANETs) and wireless sensor networks (WSNs) are two recently-developed technologies that uniquely function without xed infrastructure support, and sense at scales, resolutions, and durations previously not possible. While both offer great potential in many applications, developing software for these types of networks is extremely dffcult, preventing their wide-spread use. Three primary challenges are (1) the high level of dynamics within the network in terms of changing wireless links and node hardware con gurations, (2) the wide variety of hardware present in these networks, and (3) the extremely limited computational and energy resources available. Until now, the burden of handling these issues was put on the software application developer. This dissertation presents three novel programming models and middleware systems that address these challenges: Limone, Agilla, and Servilla. Limone reliably handles high levels of dynamics within MANETs. It does this through lightweight coordination primitives that make minimal assumptions about network connectivity. Agilla enables self-adaptive WSN applications via the integration of mobile agent and tuple space programming models, which is critical given the continuously changing network. It is the rst system to successfully demonstrate the feasibility of using mobile agents and tuple spaces within