Made available in DSpace on 2014-06-12T15:52:08Z (GMT). No. of bitstreams: 1 license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2008 / O projeto de software visa descrever os principais aspectos do sistema a ser construído através de mecanismos que ajudam a raciocinar sobre a complexidade. Dentre as ativi- dades do projeto de software, destaca-se a elaboração e documentação da arquitetura, um dos principais mecanismos para raciocinar e lidar com essa complexidade. Uma das principais metas do projeto da arquitetura é a modularizadão do sistema através do esta- belecimento de design rules que deverão ser obedecidas pelos desenvolvedores. Exemplos de design rules estabelecidas no projeto da arquitetura são os serviços disponibilizados pelos componentes e as regras de comunicação entre estes. A modularizacão dos sistemas de software também motivou o surgimento da Pro- gramação Orientada a Aspectos (POA). Entretanto estudos recentes mostraram que a utilização da POA apesar de ser um meio efetivo para modularizacão de interesses trans- versais, pode prejudicar a modularidade dos demais interesses se design rules não forem estabelecidas pelo projetista. Muitas das design rules necessárias para melhorar a modu- laridade de sistemas orientados a aspectos são definidas na fase de projeto da arquitetura do software. Para criação e documentação do projeto da arquitetura uma das principais abordagens é a utilização de Linguagens de Descrição de Arquitetura (LDA), que permitem descrever a arquitetura de forma clara e não ambígua, possibilitando a verificação de uma série de propriedades que antes são poderiam ser analisadas depois do implementação do software. O problema na utilização desta abordagem é que o modelo de arquitetura utilizado pela maioria das LDAs, formado por abstrações como componentes e conectores, é diferente do modelo baseado em objetos utilizado por muitas linguagens de programação, tornado difícil o mapeamento e a consistência entre essas fases do desenvolvimento. Entretanto, para garantir a modularidade do sistema e as propriedades arquiteturais obtidas através de uma LDA, é necessário apenas garantir que as design rules estabelecidas por esta são obedecidas pelo código desenvolvido. Neste trabalho propomos um mapeamento das design rules implicitamente definidas por uma linguagem de descrição arquitetural para uma linguagem de descrição de design rules, responsável por verificar se estas estão sendo obedecidas no código desenvolvido. A verificação das design rules permite garantir que a modularidade e as propriedades arqui- teturais obtidas através do projeto da arquitetura sejam válidas no código desenvolvido. A LDA escolhida foi a linguagem AspectualAcme, que utiliza os conceitos da orientação a aspectos, permitindo que as design rules geradas melhorem também a modularidade de sistemas orientados a aspectos. Para diminuir os custos com a tradução, também foi construída uma ferramenta capaz de gerar automaticamente, a partir de uma especificação válida em AspectualAcme, as regras na linguagem de descrição de design rules. Além da economia de tempo dos desenvolvedores, o suporte automático para tradução evita que erros sejam cometidos ou que design rules sejam esquecidas, garantindo dessa forma as propriedades verificadas no modelo arquitetura e a modularidade do sistema

Um dos principais interesses na descoberta do conhecimento e mineração de dados é a indução de regras de associação. Regras de associação caracterizam as relações entre os dados a partir de um conjunto de dados estruturado com transações, onde cada transação contém um subconjunto de itens. Seja X e Y dois conjuntos de itens disjuntos, então a regra X → Y define um relacionamento, isto é, a dependência ou a co-ocorrência entre os conjuntos X e Y. Um dos algoritmos mais conhecidos para geração de regras de associação é o algoritmo Apriori. Ele explora regras de associação que respeitam o limiar suporte mínimo, ou seja, as regras devem aparecer em uma quantidade mínima de transações. Esse limiar tem a capacidade de controlar a quantidade de regras extraídas durante a mineração. Entretanto, a frequência ou suporte não consegue medir o nível de interesse de uma regra. Para medir a importância ou interesse de uma regra em relação a outras foram desenvolvidas medidas de interesse. Tais medidas são calculadas a partir das frequências dos conjuntos de itens X, Y e do par XY. Apesar das medidas de interesse realizarem uma filtragem das regras desinteressantes, elas não acarretam na diminuição no tempo de execução da mineração. Para vencer essa dificuldade, técnicas que exploram diretamente regras de associação ótimas foram desenvolvidas. Um conjunto de regras de associação ótimas é um conjunto de regras que otimiza uma determinada medida de interesse. Na literatura existem muitos trabalhos que buscam esse tipo de conjunto de regras de forma direta e eficiente. O trabalho corrente segue esta mesma direção e visou a melhoria dessa tarefa por descobrir uma quantidade arbitrária de regras de associação ótimas. As abordagens anteriores apresentam um entrave em especial, que é a utilização do algoritmo Apriori. Tal técnica realiza uma busca em largura sobre os conjuntos de itens. No entanto, as técnicas mais promissoras que descobrem regras ótimas realizam busca em profundidade sobre o espaço de busca de regras. Em virtude dessa característica, neste trabalho foi adotada a técnica FP-growth, que realiza uma busca em profundidade sobre os conjuntos de itens explorados. Além da adoção da técnica FP-growth, foram desenvolvidas novas estratégias de poda e uma nova estratégia de busca na travessia do espaço de regras. Todas essas inovações foram adicionadas aos algoritmos desenvolvidos no corrente trabalho e proporcionaram melhor eficiência (tempo de execução) em relação ao algoritmo baseline em todos os testes. Tais testes foram realizados sobre conjuntos de dados reais e artificiais. / The induction of association rules is one of the main interests in knowledge discovery and data mining. Association rules describe the relationships between data from a transactional dataset, so that each transaction contains a subset of items. Let X and Y be two disjoint itemsets, then any rule X → Y defines a relationship that represents the dependence or co-occurrence between itemsets X and Y. Apriori is the best-known algorithm to generate association rules. It generates association rules that satisfy a user defined minimum support threshold. This means the rules should occur at least in an arbitrary number of transactions from a dataset. This threshold limits the number of association rules generated by Apriori. Yet, it is not possible to measure the interest of a rule through support. For that, interestingness measures were developed to assess the importance or interest of a rule. The values of these interestingness measures are obtained through frequencies of X, Y and XY. However, it is still an expensive task mining all the association rules and then filter them according to an interestingness measure. To overcome this difficulty, techniques to induce optimal association rules have been developed. Optimal association rules are a ruleset that optimize an arbitrary interestingness measure. In the literature, there are many papers which aim at searching for optimal association rules directly and efficiently. The current MSc thesis follows this direction, aiming at improving this objective. Previous approaches share one obstacle in particular: the use of Apriori. This algorithm performs a breadth-first search on the itemsets space. However, the most promising techniques to find optimal rules perform a depth-first search on the space of rules. Hence, in this research we adopted the FP-growth algorithm, which performs a depth-first search on the itemsets space. Besides using this algorithm, new rule pruning techniques and a new search space traversing on the space rules were developed. The algorithms developed in the current research contain all these innovations. In all tests, the proposed algorithms surpassed the baseline algorithms in terms of efficiency. These tests were conducted on real and articial datasets.

[pt] Um controlador Heurístico Adaptativo baseia-se num conjunto de regras lingüísticas para conduzir um processo com modelo impreciso ou complexo ao estado desejado. O comportamento do processo deve respeitar os requisitos de performance predefinidos. Para satisfazer estes objetivos, a estrutura interna do controle sofre mudanças para adequá- la as condições vigentes no processo. Os métodos de adaptação abordados consideram a modificação de uma estrutura matricial interpretada como as correções incrementais, compatíveis com os ajustes a serem efetuados sobre o processo, ou como regras, constituídas por variáveis nebulosas, que requerem manipulações adicionais para produzir a saída do controlador. Em qualquer dos casos, a adaptação é realizada a partir de uma Tabela de Índices de Performance. Para facilitar a sua obtenção é implementado um procedimento, que fornece a representação matricial das regras lingüísticas, concatenadas na forma de um Algoritmo Lingüístico de Controle. O comportamento dinâmico do Sistema, composto pelos Controladores Heurísticos e por processos com modelos distintos, é considerado para Tabelas de índices de Performance com várias dimensões. As regras lingüísticas, correlacionadas com estas tabelas, foram elaboradas com diversas classes de atributos. As simulações realizadas concentram-se sobre os parâmetros dos controladores, que influenciam significativa- Os estudos abordam também o comportamento da estrutura interna destes controladores e o seu desempenho em termos da velocidade de atuação sobre o processo. / [en] A heuristic Controller uses a set of linguistic rules, which are derived from expertise or human operators´ skills, in order to achieve control of processes that have inaccurate or complex models. An adaptative Heuristic Controller adjusts the set of rules in an automatic and continuous way, aiming to achieve prescribed objectives indicated by a performance measure. The adaptative procedures modify a matrix, the elements of which are either incremental corrections or numeric rules associated with fuzzy variables. In both cases a Performance Index Table and a learning method are employed to correct that matrix. The Performance Table is a matrix calculated from a set of linguistic rules. The controllers are implemented with different Performance Tables, considering various sets of linguistic values and quantization levels. The dynamic behaviour of overdamped and underdamped processes is investigated. The performance of simulated systems is analyzed with respect to relevant parameters that affect their behaviour.

Metabolic syndrome is taking epidemic proportions, especially in developed countries. Each risk factor component of the syndrome independently increases the risk of developing coronary artery disease. The risk factors are obesity, dyslipidemia, hypertension, diabetes type 2, insulin resistance, and microalbuminuria. Nuclear receptors is a family of receptors that has recently received a lot of attention due to their possible involvement in metabolic syndrome. Putting the receptors into context with their co-factors and ligands may reveal therapeutic targets not found by studying the receptors alone. Therefore, in this thesis, interactions between genes in nuclear receptor pathways were analysed with the goal of investigating if these interactions can supply leads to biomarkers for metabolic syndrome. Metabolic syndrome donor gene expression data from the BioExpressä, database was analysed with the APRIORI algorithm (Agrawal et al. 1993) for generating and mining association rules. No association rules were found to function as biomarkers for metabolic syndrome, but the resulting rules show that the data mining technique successfully found associations between genes in signaling pathways.

Objectives: To develop a clinical prediction rule (CPR) for the diagnosis of pleural tuberculosis (PT) in patients with pleural exudates in Peru. Methods: Clinical and laboratory information was collected from patients with exudative pleural effusion attending two reference hospitals in Lima, Peru. Predictive findings associated with PT in a multiple logistic regression model were used to develop the CPR. A definite diagnosis of PT was based on a composite reference standard including bacteriological and/or histological analysis of pleural fluid and pleural biopsy specimens. Results: A total of 238 patients were included in the analysis, of whom 176 had PT. Age, sex, previous contact with a TB patient, presence of lymphadenopathy, and pleural adenosine deaminase (ADA) levels were found to be independently associated with PT. These predictive findings were used to construct a CPR, for which the area under the receiver operating characteristics curve (AUC) was 0.92. The single best cut-off point was a score of ≥60 points, which had a sensitivity of 88%, specificity of 92%, a positive likelihood ratio of 10.9, and a negative likelihood ratio of 0.13. Conclusions: The CPR is accurate for the diagnosis of PT and could be useful for treatment initiation while avoiding pleural biopsy. A prospective evaluation is needed before its implementation in different settings.

No description available.

No abstract available. / Dissertation (LLM)--University of Pretoria, 2010. / Mercantile Law / unrestricted

The aim of the thesis is to address issues concerning modelling and evaluation of monetary policy by obtaining targeting rules from optimisation techniques using welfare loss functions that capture asymmetries and zone targeting behaviours. The motivation is that the specification of the most widely used monetary policy rule, i.e. the Taylor rule, may not adequately capture the stylised key features of monetary policy practice as has been shown by Nobay and Peel (2003), Aksoy et al. (2006) and Boinet and Martin (2008). The thesis also addresses the importance of the behaviour of certain financial asset prices and their implications in monetary policy decision making. It also analyses the impact of uncertainty about the true state of the economy on domestic interest rates. First, the response of monetary policy to deviations of inflation and output from their target values based on a framework that allows asymmetric and zone targeting monetary authorities’ preferences is estimated.1 Second, the monetary policy reaction function, which is augmented with a comprehensive index that collects and synthesises information from the financial asset markets is estimated for South Africa based on a framework that allows asymmetric and zone targeting monetary authorities’ preferences.2 Third, the impact of uncertainty about the state of the economy on monetary policy in South Africa using a framework that allows asymmetric and zone targeting monetary authorities’ preferences is analysed. The main findings are that the monetary authorities’ response towards inflation is zone symmetric and their response to output fluctuations is asymmetric. The second major finding is that the conditions in the financial asset markets form an important information set for the monetary authorities and that the monetary authorities pay close attention to the conditions in these markets by placing an equal weight on financial asset markets booms and recessions. The empirical results also reveal a significant impact of uncertainty about the state of the economy on domestic interest rates during the inflation targeting period and that the monetary authorities exhibit discretionary behaviour when implementing monetary policy under uncertainty. The thesis contributes to the body of knowledge in the field of economics by addressing important issues in monetary policy design and conduct using a framework that capture the stylised key features of monetary policy practice. All these issues are important in design and conduct of monetary policy. They are currently debated at many central banks including South Africa. / Thesis (PhD)--University of Pretoria, 2011. / Economics / unrestricted

The objective of this study is to do critical analysis if the new Companies Act, with specific reference capital maintenance rules. Furthermore, this study will compare the current Companies Act with the new Companies Act, with a specific focus on sections 44, 45 and 48 of the new Companies Act and their comparison to sections 38, 85 and 226 of the current Companies Act. The next objective is to establish what impact the new piece of legislation will have on South African companies and whether the deficiencies in the current Companies Act have been addressed by the new Companies Act. The final objective is to establish whether this new piece of legislation gives adequate protection for the shareholders of a company. This study will focus on certain aspects of capital maintenance and excludes a comprehensive study of the capital maintenance rules, as the focus will be on certain sections in the current Companies Act and also the new Companies Act. This study will focus on the comparison between the new and current Companies Act. Furthermore, the focus will also be on the protection of the creditors of a company when analysing the different sections of the current companies act and the new companies act. / Dissertation (LLM)--University of Pretoria, 2011. / Mercantile Law / unrestricted

In this dissertation, I examine the changes to the nature of the accounting paradigms of U.S. GAAP and International Financial Reporting Standards (IFRS) over the course of the U.S. GAAP and IFRS convergence project. I further examine whether the changes to the nature of IFRS following convergence impacts the financial reporting quality. The motivation for this study is to provide an initial review of the progress of the convergence process between U.S. GAAP and IFRS that aims to converge both sets of standards towards more principles-based paradigms. The ultimate goal of the convergence process was the development of globally recognized high quality financial reporting standards (FASB, 2002) and the development of principles-based accounting standards was identified as an essential component of such a goal. Extant literature and professional practice agree that U.S. GAAP is more rules-based whereas IFRS is more principles-based. Thus, both the International Accounting Standards Board (IASB) and the U.S. Financial Accounting Standards Board (FASB) agreed that the convergence process would be an ideal vehicle to converge both sets of standards towards more principles-based paradigm. I document that over the course of the convergence project, the underlying accounting paradigm of U.S. GAAP has remained consistent whereas the accounting paradigm of IFRS has become more rules-based. Amendments to existing International Standards and newer standards added over the course of the convergence have moved IFRS towards a more rules-based nature which was not the intended outcome of the convergence process. I further examine if the changes in rules vs. principles-based nature of IFRS has impacted the accounting quality. Using a firm level instrument developed in Folsom et al. (2016) that measures the extent to which firms rely on principles-vs –rules-based accounting, standards I find a relation between firm reliance on principles-based standards and earnings persistence. I also find an association between firm reliance on principles-based standards and earnings ability to predict future cash flows as well as concurrent returns. More, importantly the results of my study provide initial evidence that these associations are significantly manifested in the post-convergence period.