Investigation into the requirements for an integrated computer-aided engineering environment

A dissertation submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, in fulfilment of requirements for the degree of Master of Science. Johannesburg, 1991.Integration of islands of computer Assisted Functions is becoming increasingly important in many organisations and is being driven by the need for Data Sharing and the reduction in Duplication of Effort in order to achieve an Increasingly competitive edge. Technology is increasingly providing the means of taking the "intagrated Organisation" out of the realms of an "idealistic dream World" into the harsh environment of Reality. [Abbreviated Abstract. Open document to view full version

Design and Optimization of Mobile Cloud Computing Systems with Networked Virtual Platforms

A Mobile Cloud Computing (MCC) system is a cloud-based system that is accessed by the users through their own mobile devices. MCC systems are emerging as the product of two technology trends: 1) the migration of personal computing from desktop to mobile devices and 2) the growing integration of large-scale computing environments into cloud systems. Designers are developing a variety of new mobile cloud computing systems. Each of these systems is developed with different goals and under the influence of different design constraints, such as high network latency or limited energy supply. The current MCC systems rely heavily on Computation Offloading, which however incurs new problems such as scalability of the cloud, privacy concerns due to storing personal information on the cloud, and high energy consumption on the cloud data centers. In this dissertation, I address these problems by exploring different options in the distribution of computation across different computing nodes in MCC systems. My thesis is that "the use of design and simulation tools optimized for design space exploration of the MCC systems is the key to optimize the distribution of computation in MCC." For a quantitative analysis of mobile cloud computing systems through design space exploration, I have developed netShip, the first generation of an innovative design and simulation tool, that offers large scalability and heterogeneity support. With this tool system designers and software programmers can efficiently develop, optimize, and validate large-scale, heterogeneous MCC systems. I have enhanced netShip to support the development of ever-evolving MCC applications with a variety of emerging needs including the fast simulation of new devices, e.g., Internet-of-Things devices, and accelerators, e.g., mobile GPUs. Leveraging netShip, I developed three new MCC systems where I applied three variations of a new computation distributing technique, called Reverse Offloading. By more actively leveraging the computational power on mobile devices, the MCC systems can reduce the total execution times, the burden of concentrated computations on the cloud, and the privacy concerns about storing personal information available in the cloud. This approach also creates opportunities for new services by utilizing the information available on the mobile device instead of accessing the cloud. Throughout my research I have enabled the design optimization of mobile applications and cloud-computing platforms. In particular, my design tool for MCC systems becomes a vehicle to optimize not only the performance but also the energy dissipation, an aspect of critical importance for any computing system

Uma proposta para rastreabilidade no desenvolvimento de software

Orientador: Mario JinoTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de ComputaçãoResumo: Rastreabilidade tem sido um tópico de pesquisa no desenvolvimento de software por pelo menos 40 anos, sendo adicionada a muitos padrões, como o DOD-STD-2167A e o IEEE 830-1998. Este último, por exemplo, afirma que uma boa especificação de requisitos de software deve ser rastreável. A rastreabilidade fornece muitos benefícios para projetos de software, tais como: identificação das razões para decisões de design, prevenção de problemas de dependência, identificação de responsabilidades em um projeto, estimação de impacto e de custo de modificações, e medição do progresso de desenvolvimento. Sucintamente, a rastreabilidade permite a geração de um produto de melhor qualidade. Dois principais focos surgiram na literatura nos últimos anos: desenvolvimento baseado em modelo e geração automática de rastros. O primeiro trata da modelagem de rastreabilidade, definindo relações e elementos de um projeto; o segundo trata da descoberta automática de relações entre elementos. Vários conceitos foram definidos até agora, como rastreabilidade bidirecional, rastreabilidade de especificações pré e pós-requisitos, rastreabilidade horizontal e vertical, e rastreabilidade explícita e implícita. Embora haja um consenso geral sobre a maioria dos conceitos relacionados a rastreabilidade, há uma falta de consenso sobre como, e o quê, deve ser rastreado; não há consenso sobre: quais relações são relevantes para os projetos de desenvolvimento de software, quais elementos devem ser rastreados, como as mudanças nos elementos de um projeto afetam as relações existentes, ou como atualizar as relações dadas certas mudanças. Os modelos de rastreabilidade visam responder a essas questões fornecendo um padrão para ser usado como uma guia em projetos de desenvolvimento de software; entretanto, não há consenso sobre o que um modelo deve conter. Existe uma variedade de modelos, cada um considerando diferentes tipos de relações, elementos, e possuindo diferentes focos. Além disso, a maioria dos modelos possui problemas que tornam o seu uso difícil, ou até mesmo impossível; por exemplo, existem modelos que não descrevem - suficientemente ou em nada - as ligações de rastreabilidade que propõem. Este trabalho visa a ajudar nesta questão, fornecendo uma contribuição dupla: um modelo de referência para criar e avaliar modelos de rastreabilidade, e um metamodelo abrangente, construído em cima do modelo de referência, para adicionar rastreabilidade a projetos de desenvolvimento de software. Nosso Modelo de Referência para rastreabilidade define os elementos básicos em um modelo de rastreabilidade e define conjuntos básicos de: ações, tipos de ligações, tipos de artefatos, e processos. Propriedades necessárias para o conjunto de tipos de ligações e o conjunto de tipos de artefatos também são fornecidas. Nosso Metamodelo para rastreabilidade é composto por: um modelo conceitual descrevendo e organizando os elementos de rastreabilidade; um conjunto de tipos de artefatos representando as atividades definidas no Modelo de Referência, além de um conjunto de tipos de artefatos criados para registrar decisões de design; um conjunto de tipos de ligações que modelam diferentes relações de rastreabilidade; e um conjunto de processos para garantir a consistência de projetosAbstract: Traceability has been a topic of research in software development for at least 40 years, being added to many standards, such as the DOD-STD-2167A and the IEEE 830-1998. The latter, for instance, states that a good software requirements specification should be traceable. Traceability provides many benefits to software projects, such as: identification of the reasons for design decisions, avoidance of dependency issues, identification of accountability in a project, estimation of impact and cost of modifications, and measurement of development progress. Succintly, traceability allows the generation of a better quality product. Two main focuses have emerged in the literature in recent years: model-based development and automated trace generation. The former concerns modeling traceability by defining relations and elements in a project; the latter concerns automatic discovery of relations between elements in a project. Several concepts have been defined so far, such as bidirectional traceability, pre and post-requirements specification traceability, horizontal and vertical traceability, and explicit and implicit traceability. While there is general consensus on most concepts related to traceability, there is a lack of consensus on how, and what, should be traced; there is no consensus on which relations are relevant for software development projects, which elements should be traced, how changes in elements of a project affects existing relations, or how to update relations given certain changes. Traceability models aim to answer these questions by providing a standard to be used as a guide in software development projects; however, there is no consensus on what a model should contain. There is a variety of models, each considering different types of relations, elements, and having distinct focuses. Also, the majority of models have issues which makes them difficult or even impossible to use; for instance, there are models which do not describe - sufficiently or at all - traceability links which they propose. This work aims to help in this issue by providing a twofold contribution: a reference model for creating and evaluating traceability models, and a comprehensive metamodel, built on top of the reference model, to add traceability to software development projects. Our Reference Model for traceability defines the basic elements in a traceability model and defines basic sets of: actions, link types, artifact types, and processes. Necessary properties for the sets of link types and artifact types are also provided. Our Metamodel for traceability is composed of: a conceptual model describing and organizing the elements of traceability; a set of artifact types representing the activities of the Reference Model, plus a set of artifact types created to record design decisions; a set of link types modeling different traceability relations; and a set of processes to ensure project consistencyDoutoradoEngenharia de ComputaçãoDoutor em Engenharia Elétrica1142618CAPE