Thesis (M.Tech.: Computer Studies)-Dept. of Computer Science, Durban Institute of Technology, 2002. / Computer programming has been a science for approximately 50 years. It this time there havebeen two major paradigm shifts that have taken place. The first was from “spaghetti code” to structured programs. The second paradigm shift is from procedural programs to object oriented programs. The change in paradigm involves a change in the way in which a problem is approached, can be solved, as well as a difference in the language that is used. The languages that were chosen to be studied, are COBOL and Java. These programming languages were identified as key languages, and the languages that software development are the most reliant on. COBOL, the procedural language for existing business systems, and Java the object oriented language, the most likely to be used for future development. To complete this study, both languages were studied in detail. The similarities and differences between the programming languages are discussed. Some key issues that a COBOL programmer has to keep in mind when moving to Java were identified.

Learning to program is recognised nationally and internationally as a complex task that novices find challenging. There exist many endeavours to support the novice in this activity, including software tools that aim to provide a more supportive environment than that provided by standard software facilities, together with schemes that reduce the underlying complexity of programming by providing accessible micro-worlds in which students develop program code. Existing literature recognises that learning to program is difficult because of the need to learn the rules and operation of the language (program formulation), and the concurrent need to interpret problems and recognise the required components for that problem (problem formulation). This thesis describes a new form of learning support that addresses that dual task of program and problem formulation. A review of existing teaching tools that support the novice programmer leads to a set of requirements for a support tool that encompasses the processes of both program and problem formulation. This set of requirements is encapsulated in a conceptual framework for software tool development. The framework demonstrates how the requirements of a support tool can be met by performing a series of automated analyses at different stages in the student's development of a solution. An extended series of observations demonstrates the multi-faceted nature of problems that students encounter whilst they are learning to program and how these problems can be mapped onto the different levels of programs and problem formulation. These observations and the framework were used to inform the development of SNOOPIE, a sample instantiation of the framework for learning Java programming. This software tool has been fully evaluated and demonstrated to have a significant impact on the learning process for novice Java programmers. SNOOPIE is fully integrated into a current introductory programming module and a future programme of work is being established that will see SNOOPIE integrated with other established software tools.

Functional programming (FP) has progressively become more prevalent and techniques from the FP paradigm has been implemented in many different Imperative object-oriented programming (OOP) languages. However, there is no indication that OOP is going out of style. Nevertheless the increased popularity in FP has sparked new discussions across the Internet between the FP and OOP communities regarding a multitude of related aspects. These discussions could provide insights into the questions and challenges faced by programmers today. This thesis investigates these online discussions in a small and contemporary scale in order to identify the most discussed aspect of FP and OOP. Once identified the statements and claims made by various discussion participants were selected and compared to literature relating to the aspects and the theory behind the paradigms in order to determine whether there was any discrepancies between practitioners and theory. It was done in order to investigate whether the practitioners had different ideas in the form of best practices that could influence theories. The most discussed aspect within FP and OOP was ​immutability and state​ relating primarily to the aspects of ​concurrency ​ and ​performance​ . This thesis presents a selection of representative quotes that illustrate the different points of view held by groups in the community and then addresses those claims by investigating what is said in literature. It was shown that there were no direct discrepancies between the practitioners and the theory.

O método de elementos analíticos simula escoamentos subterrâneos por meio da superposição de soluções conceituais. No contexto do método, inomogeneidade é uma região bem definida de condutividade hidráulica constante. A diferença de condutividade hidráulica entre a inomogeneidade e o meio em que está inserida causa uma descontinuidade (salto) no potencial de descarga. Tradicionalmente este salto é simulado usando polinômios de primeiro ou segundo grau. O presente trabalho usa polinômios splines quadráticos para interpolar os saltos ocorridos no potencial de descarga ao longo das bordas de inomogeneidades. Paralelamente, a formulação tradicional de interpolação dos saltos no potencial de descarga é estendida para qualquer grau. Os principais elementos que compõe o método são descritos e implementados. O programa computacional resultante (AEM) foi desenvolvido integrado a um sistema de informações geográficas de código-aberto (JUMP). O programa permite a integração com outros sistemas de informações geográficas baseados em JAVA, guardando independência do SIG residente. O projeto do programa AEM/JUMP é baseado na programação orientada a objetos e apresentou grande afinidade com o método de elementos analíticos, havendo identificação entre os conceitos de elemento (usado pelo método) e de objeto (usado pela programação). Conceitos de padrões de projeto são utilizados objetivando ampliar as facilidades de leitura, entendimento, otimização e modificação do código fonte, já disponibilizadas pela programação orientada a objetos. Problemas conceituais são abordados usando as formulações propostas. A interpolação por splines quadráticas mostrou-se eficiente e precisa. Considerando as soluções exatas, o erro médio sobre a área de estudo foi inferior a 0,12%. O AEM/JUMP foi aplicado à região da Lagoa do Bonfim - RN com o objetivo de determinar as isolinhas de cargas hidráulicas. Os resultados foram comparados com estudo anterior, onde obteve resultados compatíveis, comprovando a aplicação do método e de sua implementação. Foram incorporadas ao problema da Lagoa do Bonfim características geométricas do contorno do oceano e de aluviões existentes no entorno da lagoa, demonstrando a utilidade do programa para gerar diferentes cenários de simulação. / The analytical elements method simulates underground draining through the superposition of conceptual solutions. In the method\'s context, inhomogeneity in defined as a clearly set region of constant hydraulic conductivity. Inhomogeneity hydraulic conductivity differences and the environment in which they are inserted cause a discontinuity (jump) in the discharge potential. Traditionally, this jump is simulated using first or second degree polynomials.The present work presents a formulation that uses quadratic spline polynomials to interpolate jumps occurred in the discharge potential through inhomogeneity borders. At the same time, the traditional formulation of discharge potential jump interpolation is extended to any degree. The main elements that compose the method are described and implemented. The resulting computational program (AEM) was developed integrated to an open code geographic information system (JUMP). The program permits the integration with other geographic information systems based on JAVA, keeping its independence from resident SIG. The architecture project program AEM/JUMP is based on object-oriented programming and presented great affinity with the analytical element method, showing identification among element concepts (used by the method) and the object (used by the program). Standard project concepts are used, seeking to widen source code reading possibilities, understanding, optimization and modifications already available through the object-oriented programming. Conceptual problems are approached with proposed formulations. Quadratic spline interpolation proved to be efficient and precise. Considering exact solutions, average mistake on study area was lower than 0.12%. AEM/JUMP was applied to the Lagoa do Bonfim (RN) lake region with the aim of establishing hydraulic charge isolines. Results were compared with the previous study, where compatible results had been obtained, thus proving method feasibility and implementation. Geometric features of surrounding areas and alluvion regions present around the lake area were incorporated to the original problem, demonstrating the usefulness of the program to generate different simulation scenarios.

Com o avanço tecnológico dos últimos anos passou a ser normal vermos microprocessadores com múltiplos núcleos (cores). A expectativa é de que o crescimento da quantidade de núcleos passe a ser maior do que o crescimento da velocidade desses núcleos. Assim, além de se preocuparem em otimizar algoritmos sequenciais, os programadores começaram a dar mais atenção às possibilidades de aproveitamento de toda a capacidade oferecida pelos diversos cores. Existem alguns modelos de programação que permitem uma abordagem concorrente. O modelo de programação concorrente mais adotado atualmente é o baseado em threads, que utiliza memória compartilhada e é adotado em Java. Um outro modelo é o baseado em troca de mensagens, no qual as entidades computacionais ativas são denominadas atores. Nesse trabalho, estudamos a linguagem Scala e seu modelo de atores. Além disso, implementamos em Scala uma versão paralela de um algoritmo de classicação que simula o sistema imunológico dos animais, o AIRS paralelo, e comparamos seu desempenho com a versão em Java. / With the technological advance of the last years it has been normal to see microprocessors with multiple cores. The expectation is that the growth of number of cores becomes greater than the growth of the speed of these cores. This way, besides worrying about optimizing sequential algorithms, developers started to give more attention to the possibilities of proting from all capacity offered by the cores. There exists a few programming models that allow a concurrent approach. In these days, the most adopted concurrent programming model is the one based on threads, which uses shared memory and is adopted in Java. Other model is based on message passing, on which the active computational entities are called actors. In this project, we studied Scala language and its model based on actors. Besides that, we implemented in Scala a parallel version of a classification algorithm that simules the immune system of the animals, parallel AIRS, and compared its performance with the Java version.

Em engenharia, modelos podem ser entendidos como representações das características principais de um objeto, criadas com o propósito ele permitir a visualização e compreensão da estrutura e do comportamento do objeto, antes de sua construção. A estrutura de um objeto de engenharia pode ser definida por um modelo geométrico que descreve, exata ou aproximadamente, suas formas e dimensões materiais. O comportamento pode ser descrito por um conjunto de equações diferenciais de um modelo matemático que nos permite prever, sob certas condições, os efeitos de ações externas sobre o objeto. A solução do modelo matemático pode ser obtida pela análise computacional numérica de um modelo mecânico do objeto, através do método dos elementos finitos e/ou método dos elementos de contorno. Nesse trabalho, apresentamos um Sistema de Modelagem Estrutural Orientado a Objetos denominado OSW - Object Structural Workbench, destinado ao desenvolvimento de programas de análise e visualização de modelos em engenharia de estruturas. Na primeira parte do texto, introduzimos os fundamentos utilizados no desenvolvimento do sistema. Na segunda parte, descrevemos como empregar as bibliotecas de classes de OSW na construção de um programa de modelagem e apresentamos a alguns resultados obtidos com o sistema. / In engineering, models may be thought as representations for the main characteristics of an object. Such representations enable us to visualize and understand the object structure and behaviour before constructing the object itself. The engineering ohject structure can be defined by a qeometric model which faith ful or approximately describes the object shape and size. The object behaviour can be ruled by a differential equations set from a mathematical model, which enables us to predict the effects of external forces acting on the object. The solution for the mathematical model can be obtained by applying the method of finite elements or method of boundary elements to an object mechanical model. In the text, we present an Object Oriented Structural Modeling System called OSW - Object Structural Workbench. The system has been designed to aid the development of computer programs for analysis and visualization of structural models. The text has been designed to aid the development of computer programs for analysis and visualization of structural models. The text has been divided into two parts. At the first one, we introduce the mathematical and computational basis employed in OSW construction. At the second one, we describe how to use the OSW class libraries to develop our own structural modeling applications, and also we present some results from OSW.

Les grands robots marcheurs sont des systèmes mécatroniques poly-articulés complexes qui cristallisent la volonté des humains de conférer leurs capacités à des artefacts, l’une d’entre elle étant la locomotion bipède, et plus particulièrement la conservation de l’équilibre face à des perturbations extérieures. Cette thèse propose un stabilisateur postural ainsi que sa mise en œuvre sur le système locomoteur BIP 2000.Ce robot anthropomorphique possède quinze degrés de libertés actionnés par moteurs électriques et a reçu un nouvel automate ainsi que des variateurs industriels lors de la mise à jour réalisée dans le cadre de ces travaux. Un contrôleur a été conçu et implémenté en suivant les principes de la programmation orientée objet afin de fournir une modularité qui s’inspire de la symétrie naturelle des humanoïdes. Cet aspect a conduit à l’élaboration d’un ensemble d’outils mathématiques permettant de calculer l’ensemble des modèles d’un robot composé de sous-robots dont on connaîtrait déjà les modèles. Le contrôleur permet notamment à la machine de suivre des trajectoires calculées hors ligne par des algorithmes de génération de marches dynamiques ainsi que de tester le stabilisateur postural.Ce dernier consiste en un contrôle en position du robot physique par la consigne d’un robot virtuel de modèle dégradé, commandé en effort, soumis à des champs électrostatiques contraignant sa configuration articulaire. Les tests effectués ont permis de montrer la faisabilité de la méthode. / Big walking robots are complex multi-joints mechanical systems which crystallize the human will to confer their capabilities on artefacts, one of them being the bipedal locomotion and more especially the balance keeping against external disturbances. This thesis proposes a balance stabilizer under operating conditions displayed on the locomotor system BIP 2000.This anthropomorphic robot has got fifteen electrically actuated degree of freedom and an Industrial controller. A new software has been developed with an object-oriented programming approach in order to propose the modularity required by the emulated and natural human symmetry. This consideration leads to the development of a mathematical tool allowing the computation of every modelling of a serial robot which is the sum of multiple sub robots with already known modelling. The implemented software also enables the robot to run offline generated dynamic walking trajectories and to test the balance stabilizer.We explore in this thesis the feasibility of controlling the center of gravity of a multibody robotic system with electrostatic fields acting on its virtual counterpart in order to guarantee its balance. Experimental results confirm the potential of the proposed approach.

Paradigmas e técnicas de desenvolvimento como a programação Orientada a Objetos (OO) e a programação Orientada a Aspectos (OA) procuram melhorar os níveis de reuso e manutenibilidade na produção de software. Contudo, com a introdução de mecanismos com maior poder de expressividade e, consequentemente, a possível introdução de novos tipos de defeitos, a utilização de linguagens OO e OA pode se tornar um obstáculo ao invés de um auxílio ao desenvolvimento de software. Para lidar com esse problema, nesta dissertação é proposta uma abordagem de teste estrutural de integração para programas orientados a objetos e a aspectos implementados em Java e AspectJ. É definido um modelo de fluxo de controle e de dados baseado no bytecode Java { chamado Grafo Def-Uso Contextual (ou Contextual Def-Use graph) - que é uma abstração formada pela integração dos grafos Def-Uso Orientados a Aspectos (AODU) da unidade sob teste com todas as unidades que interagem direta ou indiretamente com ela até um nível de profundidade de interação máximo ou definido pelo testador. São defiidos três critérios de teste: todos-nós-integrados-Nd, todas-arestas-integradas-Nd e todos-usos-integrados-Nd. Para automatizar o uso do modelo e critérios propostos, a ferramenta JaBUTi/AJ foi estendida. Exemplos de usos são discutidos e, por meio de um estudo experimental, uma análise de aplicabilidade da abordagem proposta é apresentada / Development paradigms and techniques such as Object-Oriented (OO) programming and Aspect-Oriented (AO) programming aim at improving reuse levels and maintenability in the software production. However, due to the introduction of mechanisms to support a greater power of expressiveness and, consequently, possible introduction of new type of faults, the use of OO and AO languages might become an obstacle instead of a benefit in the software development. To deal with these problems, in this dissertation is presented an integration structural testing approach for objectand aspect-oriented software based on Java and AspectJ. It is defined a control- and data- ow model based on Java bytecode { called Contextual Def-Use graph { that is an abstraction composed by the integration of Aspect-Oriented Def-Use graphs (AODU) of the unit under testing with the units triggered by the execution of the unit under testing considering either a maximum interaction depth level or an interaction depth level previously defined by the tester. Three testing criteria are also defined: all-integrated-nodes-Nd, all-integrated-edges-Nd and all-integrated-uses-Nd. To automate the use of the model and the testing criteria, the JaBUTi/AJ tool was extended. Usage examples are discussed to explain the approach and an exploratory study is conducted to evaluate the applicability of the proposed approach

Submitted by Maria Cristina (library@lncc.br) on 2017-04-06T18:00:17Z No. of bitstreams: 1 thesis nardes.pdf: 2049603 bytes, checksum: 3e70b3af2120ccb2b18a9454fbbb0719 (MD5) / Approved for entry into archive by Maria Cristina (library@lncc.br) on 2017-04-06T18:00:31Z (GMT) No. of bitstreams: 1 thesis nardes.pdf: 2049603 bytes, checksum: 3e70b3af2120ccb2b18a9454fbbb0719 (MD5) / Made available in DSpace on 2017-04-06T18:00:42Z (GMT). No. of bitstreams: 1 thesis nardes.pdf: 2049603 bytes, checksum: 3e70b3af2120ccb2b18a9454fbbb0719 (MD5) Previous issue date: 2016-03-04 / Agência Nacional do Petróleo, Gás Natural e Biocombustíveis / Computer modeling of reservoirs is the tool that provides the accurate description of the existing physical phenomena in the oil and gas recovery process, being of interest to both the industry and science. In oil and gas industry, the demand of commercial simulators is remarkable. At the same time, scientific simulators are able to provide researchers with the freedom and control needed by the academic activity. Among the major demands of scientific software are: (i) the scalable design, which is correlated with organized and modular code development, and (ii) the scalable execution, related to the implementation of techniques for parallel and high performance computing, due to the large amount of manipulated data and the compute-intensive numerical models produced by science. This dissertation aims to the application of techniques for modular object-oriented programming and parallel computing, with OpenMP and MPI, in a scientific simulator, developed in Fortran and used in the numerical modeling of problems related to gas flow on unconventional gas-shale reservoirs. / A modelagem computacional de reservatórios é o instrumento que permite a descrição precisa dos fenômenos físicos existentes no processo de recuperação de óleo e gás, tendo grande interesse tanto para a indústria quanto para a ciência. Na indústria de óleo e gás, é grande a demanda por simuladores comerciais de reservatórios. Por outro lado, simuladores científicos são capazes de oferecer aos pesquisadores do domínio, o controle e a liberdade necessários à atividade acadêmica. Dentre as principais demandas do software científico em geral estão (i) o design escalável, relacionado ao desenvolvimento de código de maneira organizada e modular, contribuindo para sua evolução e (ii) a execução escalável, relacionada à implementação de técnicas de computação paralela e de alto desempenho, em razão das grandes massas de dados manipuladas e dos modelos numéricos computacionalmente intensivos produzidos pela ciência. Este trabalho trata do emprego de técnicas de programação modular com orientação a objetos e de computação paralela com OpenMP e MPI em um simulador científico, escrito em Fortran e utilizado na modelagem numérica de problemas de escoamento em reservatórios não convencionais de gás em folhelhos.

Propõem-se desenvolver uma ferramenta computacional voltado a objeto que permita a visualização gráfica, de forma amigável, dos resultados da dissertação de mestrado: Sistema de avaliação da qualidade e redundância das medidas para estimação de estados em sistemas elétricos de potência. A ferramenta foi desenvolvida na plataforma Windows utilizando o Microsoft C Sharp no ambiente DotNet. Os testes foram executados em resultados em redes de 14 barras. Este trabalho foi o passo inicial para elaborar uma melhor integração das diferentes dissertações num ambiente computacional moderno, cuja visualização dos resultados seja de forma mais didática e objetiva. / This paper objects develop a user friendly, object oriented, graphic computational, tool, using the output results of the paper: Sistema de avaliação da qualidade e redundância das medidas para estimação de estados em sistemas elétricos de potência. The tool was developed on Windows platform, using Microsoft C Sharp in DotNet environment. The tests were performed using numbers of networks of 14 bars. This work was the first step to develop a better integration of dissertations in a modern computing environment, which is the viewing DSO results in a more intuitive and objective.