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We propose a methodology for the development of concurrent programs and apply it to an important class of problems: quiescence detection. The methodology is based on a novel view of programs.A key feature of the methodology is the separation of concerns between the core problem to be solved and details of the forms of concurrency employed in the target architecture and programming language. We begin development of concurrent programs by ignoring issues dealing with concurrency and introduce such concerns in manageable doses. The class of problems solved includes termination and deadlock detection.

The goal of the research described in this paper is to help prevent scenarios such as the following: a terrorist detonates a device that distributes radioactive material such as Cesium-137 or Cobalt-60 in an open space used for public sports events or demonstrations. This paper studies the efficacy of networks of static sensors on street lamps or similar infrastructures. This paper describes individual sensors, evaluates the benefits of networks of stationary sensors, and briefly discusses the potential value of integrated networks of wireless-equipped mobile security personnel with stationary radiation sensors and cameras. The paper presents mathematical analysis coupled with simulation results.

Abstract. This paper explores theories that help in (i) proving that a system composed from components satisfies a system specification given only specifications of components and the composition operator, and (ii) deducing desirable properties of components from the system specification and properties of the composition operator. The paper studies compositional systems in general without making assumptions that components are computer programs. The results obtained from such abstract representations are general but also weaker than results that can be obtained from more restrictive assumptions such as assuming that systems are parallel compositions of concurrent programs. Explorations of general theories of composition can help identify fundamental issues common to many problem domains. The theory presented here is based on predicate transformers.

We present an overview of research at the Center for Research on Parallel Computation designed to provide an efficient, portable programming model for scientific applications possessing both task and data parallelism. Fortran M programs exploit task parallelism by provid ing language extensions for user-defined process man agement and typed communication channels. A com bination of compiler and run-time system support en sures modularity, safety, portability, and efficiency. Fortran D and High Performance Fortran programs ex ploit data parallelism by providing language exten sions for user-defined data decomposition specifica tions, parallel loops, and parallel-array operations.