published_or_final_version / Mechanical Engineering / Doctoral / Doctor of Philosophy

A research report submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master of Science in Engineering. / Due to the dynamic nature of the software engineering industry there is a constant move towards new strategies for solving design problems. More specifically there is a move towards Object Oriented (OO) methodologies, presumably because of the various advantages offered in terms of maintainability, and reuse of code produced this way. As with various other aspects of the software industry there are however also problems encountered in this transition and lessons to be learned from the experience of companies who have already performed this change. This research report investigates possible guidelines for companies who are currently contemplating a change to the OO software design methodologies, by covering a collection of issues one should know about prior to this change. It also summarises the problems faced in the transition so far, the reasons for these problems and suggests possible solutions. Lastly it also investigates new trends in the OO arena. The emphasis is on South African companies and projects. The results obtained are compared with results obtained overseas to find out what the differences and similarities are. Areas of concern are also identified, where theoreticians' views have been ignored, and both South African and overeeas companies have not implemented any of the suggestions made. / Andrew Chakane 2018

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Chemical flooding is one of the most difficult enhanced oil recovery methods and was considered a high-risk process in the past. Some reasons are low and uncertain oil price, high chemical prices, lack of confidence in performance of the chemical flooding process, long project life, and reservoir and process uncertainties. However, with significant improvement in simulation and optimization tools and high oil price, chemical flooding is feasible in terms of economical and carefully implemented design. Optimization of chemical floods requires complex integration of reservoir, chemical, economics properties and also drilling and production strategies. Many of these variables are uncertain parameters and many simulations are required to capture the effect of the uncertain and decision variables. These simulations could become very expensive and may not be feasible to consider all of the required simulation models. The goal of this research is the development of a methodology for optimization and design of chemical flooding of candidate oil reservoirs. We performed a comprehensive sensitivity study of reservoir and fluid properties that have significant influence on the oil production during the chemical flooding by performing a series of reservoir simulation runs. For performing the reservoir simulation runs, this study used the UT_IRSP platform and the multiphase, multicomponent, chemical flooding simulator called UTCHEM. During the study, UT_IRSP and UTCHEM have been modified by adding new modules, functions and variables. For example, a deviated well module was implemented in UTCHEM to study deviated wells. Deviated well module allows the users to introduce deviated wells in reservoir and import the well locations similar to Eclipse or CMG simulators. A time-dependent well schedule module was implemented in the UT_IRSP framework. This enhancement allows the well placement optimization studies to find the best time to add new wells, and change the status of the well for example from a producer to an injector in order to have an optimum development plan. An advanced post processing module was added to UT_IRSP in order to design, screen, and optimize complex cases for chemical enhanced oil recovery processes such as investigating the well patterns, well spacing, and type of the well (horizontal vs. vertical wells). An experimental design and response surface methodology with integrated economic model were utilized in this study to obtain the optimum design under uncertainties and have an optimal combination of the decision variables. This methodology is based on applying multi-regression analysis and ANOVA (analysis of variance) between the objective function (i.e. dependent variable, which is net present value (NPV) in chemical flooding) and other uncertain and process variables (independent variables). The economic analysis model used the discounted cash flow method to calculate net present value at the economic life of process, internal rate of return, and growth rate of return for each simulation case. Also the optimizer, OptQuest, is launched with a goal of maximizing the mean NPV. The range and the risk associated with the optimum design was studied using Monte Carlo simulation of objective function of the response variable and other independent variables. This methodology was applied for complex chemical flood cases such as well placement, change of status of wells as a function of time or well pattern and well spacing to investigate the best well scenario from recovery and economics point of view. / text

Developing economical yet effective methods of incorporating usability engineering as an integral part of software engineering is a primary focus of human-computer interaction (HCI) research. However, much HCI research has focused primarily on inspecting and evaluating applications supporting command-line or graphical user interface (GUI) interaction styles. With the dramatic increase in virtual environment (VE) research in recent years, the HCI community is beginning to place an added emphasis on creating methodologies to ensure usability in VE development. While the demand for VE-specific usability engineering methods and criteria is dire as the amount of money invested by military, government, commercial, and industrial organizations continues to grow, widely accepted methodologies for assessing VE usability are, at this point in time, minimal. There has been a recent increase in research discussing the need of VE-specific usability engineering methodologies, but few research projects have concentrated their efforts on providing such methodologies. Therefore, application developers attempting to apply a user-centered design approach in constructing VEs must often perform largely ad-hoc assessments or in-house evaluations using existing non-VE-specific usability engineering methodologies. The primary focus of this research was to develop a method to guide usability engineering of VEs. The strategy used to develop this usability evaluation method was to modify existing usability evaluation methodologies to support VE development by leveraging the results of previous VE usability research performed at Virginia Tech and elsewhere. The result was a VE-specific usability evaluation methodology that encompasses two existing usability assessment techniques: usability inspections and formative evaluations. We applied this methodology to Crumbs, an immersive visualization VE developed at the National Center for Supercomputing Applications (NCSA). A multi-dimensional framework of VE usability characteristics was a topic of research at Virginia Tech. This framework provided the backbone for VE-specific modifications to the existing usability evaluation techniques proposed in this research. Framework design guidelines permitted usability specialists to perform guidelines-based usability inspections of Crumbs. Results gathered from the guidelines-based usability inspections were used not only to redesign the Crumbs user interface but also drive creation of a formative evaluation plan. Application of the methodology not only uncovered usability issues with Crumbs, but also provided invaluable information regarding the effectiveness of the methodology itself. We conclude this thesis by describing a usability evaluation methodology, called the Modified Concept Book Usability Evaluation Methodology, proposed to improve the usability evaluation methodology performed on Crumbs and other VEs. Our methodology was adapted from an established methodology for performing content analysis on a large volume of qualitative data. Because the realm of VEs is so vast and diverse in application domains and devices, we do not claim that our methodology supports an exhaustive usability evaluation of all VEs. However, the proposed technique is a first attempt at modifying existing usability evaluation methods, and therefore can be used as a launching pad for methodologies to evaluate other aspects of specific VE applications. / Master of Science

Orientador: Ricardo Ribeiro Gudwin / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-05T14:04:06Z (GMT). No. of bitstreams: 1 Dario_ClaudiaFilomenaBratficher_M.pdf: 11451853 bytes, checksum: 8ecd6ccb893fcfa7790f5da4d3011ffd (MD5) Previous issue date: 2005 / Resumo: Este trabalho propõe uma Metodologia Unificada para o desenvolvimento de sistemas orientados a agentes. A elaboração desta metodologia foi realizada a partir de um estudo do papel do agente dentro da Engenharia de Software e da análise de diversas metodologias orientadas a agentes encontradas na literatura, enfocando-se principalmente em três destas: MaSE (Muitiagent Systems Engimering Metkodoiogy), Prornetheus e Tropos, além da linguagem de modelagem AÜML {Agem Vnijied Modeling Language). A Metodologia Unificada proposta visa aproveitar o que há de melhor nestas metodologias, buscando elementos comuns a todas elas, de modo análogo ao que ocorreu com a metodologia unificada (RUP - Raiional Unified Process) em sistemas orientados a objetos. Para validar a Metodologia Unificada e analisar as demais metodologias, um estudo de caso foi modelado. A Metodologia Unificada se mostrou eficiente no projeto, documentação e construção de sistemas multi-agentes, sendo considerada uma metodologia detalhada e mais completa por cobrir os estágios de especificação de requisitos, de análise e de projeto no desenvolvimento de software orientados a agentes / Abstract: This work proposes a Unified Methodology for the development of agent-oriented systems. The methodology was elaborated based on a study of agent's role within software engineering and the analysis of different agent-based software development methodologies found in the literature, focusing in three main ones: MaSE (Muitiagent Systems Engineering Methodology), Prometheus and Tropos, in addition to the modeling language AUM.L (Agent Unified Modeling Language). The Unified Methodology aims at taking advantage of the best from each methodology, searching for common elements among them, in an effort similar to what happened with the Unified Methodology (RUP - Rational Unified Process) in object-oriented systems. To validate the Unified Methodology and analyze the other methodologies, a case study was developed. The Unified Methodology has shown to be efficient in the design, documentation and construction of multi-agent systems. We conclude it to be a detailed and more complete methodology, covering requirements specification, analysis and design stages of agent-based software development / Mestrado / Engenharia de Computação / Mestre em Engenharia Elétrica

Orientador: João Maurício Rosário / Dissertação (mestrado profissional) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-17T09:31:47Z (GMT). No. of bitstreams: 1 Pacifico_DouglasSozzi_M.pdf: 4000960 bytes, checksum: 072558107a877761c6e2de97a3ee0100 (MD5) Previous issue date: 2010 / Resumo: Os projetos de engenharia são até hoje amplamente baseados em processos empíricos, em metodologias ad hoc e em métodos iterativos. A experiência de quem os executa tem grande influência nos resultados obtidos por conta da falta de critérios científicos para a análise e tomada de decisões ao longo do desenvolvimento de um produto ou de um processo. As conseqüências mais comuns são os problemas de qualidade e confiabilidade, os atrasos na execução e a extrapolação dos custos previstos. Atualmente existem poucas metodologias científicas com abordagem global de um projeto, dentre elas podemos considerar o Projeto Axiomático. Desenvolvida ao longo das últimas décadas pelo Prof. Nam Pyo Suh, ela propõe dois axiomas básicos para nortear a análise e tomada de decisões em projetos de qualquer ordem, os quais são então desdobrados em teoremas e corolários específicos. Embora não possa ser demonstrada ou comprovada enquanto axioma, a metodologia tem sido constantemente validada por sua utilização bem-sucedida em diferentes especialidades técnicas, da manufatura ao desenvolvimento de produtos, da organização de empresas à tecnologia da informação. Apesar da clareza de sua proposição e da existência de modelos matemáticos para seu uso, o Projeto Axiomático não é de simples e direta aplicação às diferentes especialidades técnicas a que se propõe. Esta dissertação de mestrado tem como proposta desenvolver uma metodologia pragmática e acessível para a aplicação integral do Projeto Axiomático à tomada de decisões em projetos de dispositivos de manufatura. A metodologia desenvolvida é então validada e demonstrada através da aplicação da mesma em um caso fabril real de uma indústria de autopeças de grande porte / Abstract: Engineering design is till present times widely based on empiric processes, ad hoc methodologies and iterative methods. The experience of those who perform the task is of great influence on the outcome due to the lack of scientific criteria for both analysis and decision making along the development of a product or a process. The common consequences are quality and reliability problems, execution delays and cost overrun. Currently there are only a few scientific design methodologies with a holistic approach, Axiomatic Design among them. Developed during the last decades by Prof. Nam Pyo Suh, it proposes two basic axioms to guide the analysis and decision-making for projects of any kind, both being then unfolded in theorems and corollaries. Although not able of being neither demonstrated nor proved as axiom, the methodology has been constantly validated through its successful utilization on different technical fields, from manufacturing to product design, from organizational structures to information technology. In spite of the clearness of its proposition and the existence of mathematical models for its usage, the Axiomatic Design is not of simple and direct application to the different technical fields it is suitable for. This master's degree dissertation has the purpose of developing a pragmatic and accessible methodology for the complete application of the Axiomatic Design to the decision making regarding the design of devices. The proposed methodology is then validated and demonstrated through its application to a real industrial process in a large size multinational automotive industry / Mestrado / Projetos / Mestre em Engenharia Automobilistica

Recent advancements in technology have led to the increased use of integrated ‘systems of systems’ (SoS) which link together independently developed and usable capabilities into an integrated system that exhibits new, emergent capabilities. However, the resulting SoS is often not well understood, where secondary and tertiary effects of tying systems together are often unpredictable and present severe consequences. The complexities of the composed system stem not only from system integration, but from a broad range of areas such as the competing objectives of different constituent system stakeholders, mismatched requirements from multiple process models, and architectures and interface approaches that are incompatible on multiple levels. While successful SoS development has proven to be a valuable tool for a wide range of applications, there are significant problems that remain with the development of such systems that need to be addressed during the early stages of engineering development within such environments. The purpose of this research is to define and demonstrate a methodology called Systems Geometry (SG) for analyzing SoS in the early stages of development to identify areas of potential unintended emergent behaviors as candidates for the employment of risk management strategies. SG focuses on three dimensions of interest when planning the development of a SoS: operational, functional, and technical. For Department of Defense (DoD) SoS, the operational dimension addresses the warfighter environment and includes characteristics such as mission threads and related command and control or simulation activities required to support the mission. The functional dimension highlights different roles associated with the development and use of the SoS, which could include a participant warfighter using the system, an analyst collecting data iv for system evaluation, or an infrastructure engineer working to keep the SoS infrastructure operational to support the users. Each dimension can be analyzed to understand roles, interfaces and activities. Cross-dimensional effects are of particular interest since such effects are less detectable and generally not addressed with conventional systems engineering (SE) methods. The literature review and the results of this study have identified key characteristics or dimensions that should be examined during SoS analysis and design. Although many methods exist for exploring system dimensions, there is a gap in techniques to explore cross-dimensional interactions and their effect on emergent SoS behaviors. The study has resulted in a methodology for capturing dimensional information and recommended analytical methods for intra-dimensional as well as cross-dimensional analysis. A problem-based approach to the system analysis is recommended combined with the application of matrix methods, network analysis and modeling techniques to provide intra- and cross-dimensional insight. The results of this research are applicable to a variety of socio-technical SoS analyses with applications in analysis, experimentation, test and evaluation and training

The effective use of Information and Communications Technology (ICT) in devel-oping countries like Tanzania is crucial in order to overcome the challenges that are faced countrywide in many sectors, and to reduce the digital divide and improve the economy. ICT is becoming more and more integrated in societies worldwide, its effects are clearly seen in people’s lives as well as on countries’ economy as it opens doors for new opportunities and change the attitude of people towards learning. Secondary schools in Tanzania are facing many problems which hamper students’ learning. This in turn affects their performance in the National examinations hence reducing the growth of a learned society. This research specifically addresses the prob- lem of lack of learning and teaching materials by using ICT tools for the development and delivery of e-Learning content. The research focused on two secondary schools, namely, the Wali-Ul-Asr Seminary and Kibaha Secondary School as pilot schools in Kibaha district Pwani region. The research used courseware engineering methodology which integrated instructional design and software engineering. The research was also inspired by the concepts of participatory action research, Mode 2 knowledge production and triple helix, which incorporated stakeholders’ participation throughout the research. The main stakeholders are researchers, students, teachers, head teachers, and Ministry of Education and Vocational Training officials. This is an applied type of research addressing a practical problem in society. The out- come is a pilot package of e-Learning material comprised of sample chapters of Mathematics form III at the pilot site. Blended mode of delivery has been considered using Compact Disc/Digital Versatile Disc Read Only Memory, the Tanzania Secondary Schools e-Learning (TanSS-L) System, a customized Moodle platform and by using face to face learning.

Indiana University-Purdue University Indianapolis (IUPUI) / The development of new methods to carry out gene transfer has many benefits to several fields, such as gene therapy, agriculture and animal health. The newly established lentiviral vector systems further increase the efficiency of gene transfer dramatically. Some studies have shown that lentiviral vector systems enhance efficiency over 10-fold higher than traditional pronuclear injection. However, the timing for lentiviral vector integration to occur remains unclear. Integrating in different stages of embryogenesis might lead to different integration patterns between tissues. Moreover, in our previous study we found that the vector copy number in transgenic sheep varied, some having one or more copies per cells while other animals having less than one copy per cell suggesting mosaicism. Here I hypothesized that injection of a lentiviral vector into a single cell embryo can lead to integration very early in embryogenesis but can also occur after several cell divisions. In this study, we focus on investigating integration sites in tissues developing from different germ layers as well as extraembryonic tissues to determine when integration occurs. In addition, we are also interested in insertional mutagenesis caused by viral sequence integration in or near gene regions. We utilize linear amplification-mediated polymerase chain reaction (LAM-PCR) and next- generation sequencing (NGS) technology to determine possible integration sites. In this study, we found the evidence based on a series of experiments to support my hypothesis, suggesting that integration event also happens after several cell divisions. For insertional mutagenesis analysis, the closest genes can be found according to integration sites, but they are likely too far away from the integration sites to be influenced. A well-annotated sheep genome database is needed for insertional mutagenesis analysis.