Thesis (M.S.)--State University of New York at Binghamton, Thomas J. Watson School of Engineering and Applied Science, Department of Computer Science, 2009. / Includes bibliographical references.

Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 85-87).

Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2007. / Includes bibliographical references (leaves 155-168). Also available in electronic version.

Thesis (Ph. D.)--State University of New York at Binghamton, Thomas J. Watson School of Engineering and Applied Science, 2008. / Includes bibliographical references.

Thesis (MScIng)--University of Stellenbosch, 2008. / ENGLISH ABSTRACT: This thesis describes the design, modelling and implementation of a prototype request- processing software system, which can be used as the basis for a request processing frame- work for systems with limited request processing resources. Due to design constraints, the request-processor system described here consists of multiple processes. It is problematic to prove that a multiple process design satis es the conditions of a set of prede ned requirements. One way to verify that such a multiple process design works as intended, is to use modelchecking tools. The system was veri ed for correctness and translated into a working prototype soft- ware system. / AFRIKAANSE OPSOMMING: Hierdie tesis beskryf die ontwerp, modellering en implementering van 'n prototipe versoek- verwerking-sagtewarestelsel. Die stelsel kan gebruik word om 'n versoekverwerkings- raamwerk te ontwerp vir stelsels met beperkte versoekverwerkingshulpbronne. Die ver- soekverwerkingsstelsel bestaan uit veelvoudige prosesse. Die veelvoudige proses-ontwerp was die direkte gevolg van stelselbeperkings. Dit is problematies om te bewys dat 'n multi-proses-ontwerp korrek funksioneer. Mod- elchecking-sagteware kan gebruik word om te veri eer of 'n stelsel korrek funksioneer. Die korrektheid van die stelsel is geveri eer voordat die nale prototipe ge¨implementeer is.

L'utilisation de la virtualisation dans le domaine des serveurs d'entreprise est aujourd'hui une méthode courante. La virtualisation est une technique qui permet de faire fonctionner sur une seule machine réelle plusieurs systèmes d'exploitation. Cette technique est train d'être adoptée dans le développement des systèmes embarqués suite à la disponibilité de nouveaux processeurs classiquement destiné à ce domaine. Cependant, il y a une différence de contraintes entre les applications d'entreprise et les applications embarquées, celleci doivent respecter des contraintes de temps-réel en réalisant leurs tâches. Dans nos travaux de recherche nous avons étudié l'impact de la virtualisation sur un système d'exploitation temps-réel. Nous avons mesuré le surcoût et la latence des fonctions internes du système d'exploitation déployé sur une machine virtuelle, et nous les avons comparés à celles du système installé sur une machine réelle. Les résultats ont montré que ces métriques sont plus élevées lorsque la virtualisation est utilisée. Notre analyse a révélé que la puce électronique doit inclure des mécanismes matériels qui assistent le logiciel de contrôle des machines virtuelles afin de réduire le surcoût de la virtualisation, mais il est aussi essentiel de choisir une politique d'allocation des ressources efficace afin de garantir le respect des contraintes de temps-réel demandées par les machines virtuelles. Notre second axe de recherche concerne la transformation d'un modèle de simulation d'un système d'exploitation vers des programmes exécutables sur un système-sur-puce. Cette transformation doit également préserver une caractéristique offerte par ce modèle qui est la facilité de configuration des techniques d'allocation de ressources. Pour transformer le modèle de système d'exploitation nous avons utilisé des techniques de l'ingénierie-dirigée par les modèles. Où dans un premier temps le modèle initiale est transformé vers un autre modèle, ensuite ce second modèle est à son tour transformé automatiquement en un code source. Pour assurer la configuration du système d'exploitation finale nous avons utilisé une librairie placée entre le système d'exploitation et l'application afin d'identifier les besoins de celle-ci en termes de ressources et adapter le système à ces besoins. L'évaluation des performances de la librairie a démontré la viabilité de l'approche. / In the domain of server and mainframe systems, virtualizing a computing system's physical resources to achieve improved sharing and utilization has been well established for decades. Full virtualization of all system resources makes it possible to run multiple guest operating systems on a single physical platform. Recently, the availability of full virtualization on physical platforms that target embedded systems creates new use-cases in the domain of real-time embedded systems. In this dissertation we use an existing “virtual machines monitor” to evaluate the performance of a real-time operating system. We observed that the virtual machine monitor affects the internal overheads and latencies of the guest OS. Our analysis revealed that the hardware mechanisms that allow a virtual machine monitor to provide an efficient way to virtualize the processor, the memory management unit, and the input/output devices, are necessary to limit the overhead of the virtualization. More importantly, the scheduling of virtual machines by the VMM is essential to guarantee the temporal constraints of the system and have to be configured carefully. In a second work and starting from a previous project aiming at allowing a system designer to explore a software-hardware codesign of a solution using high-level simulation models, we proposed a methodology that allows the transformation of a simulation model into a binary executable on a physical platform. The idea is to provide the system designer with the necessary tools to rapidly explore the design space and validate it, and then to generate a configuration that could be used directly on top of a physical platform. We used a model-driven engineering approach to perform a model-to-model transformation to convert the simulation model into an executable model. And we used a middleware able to support a variety of the resources allocation techniques in order to implement the configuration previously selected by the system designer at simulation phase. We proposed a prototype that implements our methodology and validate our concepts. The results of the experiments confirmed the viability of this approach.

Thesis (M.S.)--Mississippi State University. Department of Electrical and Computer Engineering. / Title from title screen. Includes bibliographical references.

Interference is a defining feature of a wireless network. How to optimally deal with it is one of the most critical and least understood aspects of decentralized multiuser communication. This dissertation focuses on distributed transmission strategies that a transmitter can follow to achieve reliability while reducing the impact of interference. The problem is investigated from three directions : distributed opportunistic scheduling, multicast outage and transmission capacity, and ergodic transmission capacity, which study distributed transmission in different scenarios from a transmission-capacity perspective. Transmission capacity is spatial throughput metric in a large-scale wireless network with outage constraints. To understand the fundamental limits of distributed transmission, these three directions are investigated from the underlying tradeoffs in different transmission scenarios. All analytic results regarding the three directions are rigorously derived and proved under the framework of transmission capacity. For the first direction, three distributed opportunistic scheduling schemes -- distributed channel-aware, interferer-aware and interferer-channel-aware scheduling are proposed. The main idea of the three schemes is to avoid transmitting in a deep fading and/or sever interfering context. Theoretical analysis and simulations show that the three schemes are able to achieve high transmission capacity and reliability. The second direction focuses on the study of the transmission capacity problem in a distributed multicast transmission scenario. Multicast transmission, wherein the same packet must be delivered to multiple receivers, has several distinctive traits as opposed to more commonly studied unicast transmission. The general expression for the scaling law of multicast transmission capacity is found and it can provide some insight on how to do distributed single-hop and multi-hop retransmissions. In the third direction, the transmission capacity problem is investigated for Markovain fading channels with temporal and spatial ergodicity. The scaling law of the ergodic transmission capacity is derived and it can indicate a long-term distributed transmission and interference management policy for enhancing transmission capacity. / text

Thesis (M.S.)--State University of New York at Binghamton, Thomas J. Watson School of Engineering and Applied Science, Department of Computer Science, 2009. / Includes bibliographical references.

Thesis (Ph.D.)--Mississippi State University. Department of Computer Science and Engineering. / Title from title screen. Includes bibliographical references.