published_or_final_version / Computer Science / Master / Master of Philosophy

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Thesis (M. Phil.)--University of Hong Kong, 1996. / Includes bibliographical references (leaf 78-80).

published_or_final_version / Computer Science / Master / Master of Philosophy

Thesis (M. Phil.)--University of Hong Kong, 1990.

We have implemented Occam, a parallel programming language, on a uniprocessor machine (MC-68020 based HORIZON I11 running on UNIX system V.2) with simulated concurrency. Occam is a descendant of CSP with a few convenient modifications like channels used for communication and procedures. Two additions to the original language, i.e., output guards and recursion have been proposed. Front end of the compiler was developed using LEX and YACC. An innovative code generator, generator based on tree pattern matching has been used to generate the back end of the compiler, which generates efficient MC-68020 assembly code. A kernel for process administration is the runtime support provided. It has been developed entirely in ' C ' and made available as a library. This is linked with the assembly module to generate the executable version of the input Occam program. We have also interfaced our Occam compiler with Unix system V.2 source level debugger 'Sdb' so as to provide debugging support for Occam programmers. Issues involved in parallel debugging have been investigated and those demanding minimum effort have been incorporated in Occam debugger by modifying the runtime support of the uniprocessor implementation. Modifications to the uniprocessor implementation so as to make it run on a shared memory multiprocessor machine(HCL MAGNUM-P with four MC-68030 processors) are also discussed. The support provided by MAGNUM-P at the architecture and operating system levels is explained in detail. Our Occam compiler for the multiprocessor generates code, but the generated code has not been tested since the machine is not yet ready.

Occam is designed for concurrent programming on a network of transputers. AIlocation and partitioning of the program is specified within the source code, binding the program to a specific network. An altemative approach is proposed which completely separates the source code from hardware considerations. Static allocation is performed as a separate phase and should, ideally, be automatic but at present is manual. Complete hardware abstraction requires that non-local, shared communication be provided for, introducing an efficiency overhead which can be minimised by the allocation. The proposal was implemented on a network of IBM PCs, modelled on a transputer network, and implementation issues are discussed

CONKER est un noyau de communication construit à l'aide du modèle CSP.<br /> Une application décrite à l'aide de CONKER sera composée de connecteurs<br /> qui sont les obJjets charges de la communication-synchronisation et de<br /> processus qui se chargent du traitement.<br />Chaque connecteur du noyau réalise un protocole de communication particulier <br />entre les processus "applications". Ceux-ci n'utilisent que des primitives<br /> d'envoi et de réception de messages, de manière homogène et transparente à <br />la réalisation des connecteurs qui les relient.<br />Cette caractéristique de transparence, ainsi que la possibilité d'implémenter<br /> CONKER sur un ensemble de systèmes "hôtes hétérogènes", assurent une <br />transportabilité aisée des applications en environnement multi-processeurs,<br />ou sur un réseau hétérogène.<br />De part sa conception, CONKER permet de mettre â la disposition des processus<br />applications, des types de connecteurs, construits de façon incrémentale à la<br /> demande, et utilisant pour cela, les calculs de processus issus du modèle CSP.

Thesis (M.S.)--Rochester Institute of Technology, 1994. / Typescript. Includes bibliographical references (leaf 217).

Software Defined Radios (SDRs) lend themselves to flexibility and extensibility because they<br />depend on software to implement radio functionality. Cognitive Engines (CEs) introduce<br />intelligence to radio by monitoring radio performance through a set of meters and configuring<br />the underlying radio design by modifying its knobs. In Cognitive Radio (CR) applications,<br />CEs intelligently monitor radio performance and reconfigure them to meet it application<br />and RF channel needs. While the issue of introducing computational knobs and meters<br />is mentioned in literature, there has been little work on the practical issues involved in<br />introducing such computational radio controls.<br /><br />This dissertation decomposes the radio definition to reactive models for the CE domain<br />and real-time, or dataflow models, for the SDR domain. By allowing such design space<br />decomposition, CEs are able to define implementation independent radio graphs and rely on<br />a model transformation layer to transform reactive radio models to real-time radio models<br />for implementation. The definition of knobs and meters in the CE domain is based on<br />properties of the dataflow models used in implementing SDRs. A framework for developing<br />this work is presented, and proof of concept radio applications are discussed to demonstrate<br />how CEs can gain insight into computational aspects of their radio implementation during<br />their reconfiguration decision process.<br /> / Ph. D.