To date there has been significant research on the topic of financial distress prediction, due to its relevance to various stakeholders. Beaver (1966), Altman (1968) and Ohlson (1980) are generally regarded as the pioneers in this field of study, despite heavy criticism their models are widely accepted and used. Studies by Grice & Ingram (2001); Grice & Dugan (2001) and Sudarsanam & Taffler (1995) have shown that these models require to be updated regularly with new variables and coefficients due to various factors. This study proposes to add to the body of knowledge by developing a distress prediction model using a classic statistical method and financial ratios, calculated on published company data of organisations listed on the Johannesburg Stock Exchange. / Dissertation (MBA)--University of Pretoria, 2013. / zkgibs2014 / Gordon Institute of Business Science (GIBS) / MBA / Unrestricted

Monitoring and detection of abrupt changes for multivariate processes are becoming increasingly important in modern manufacturing environments. Typical equipment may have multiple key variables to be measured continuously. Hotelling's 〖T 〗^2and CUSUM charts were widely applied to solve the problem of monitoring the mean vector of multivariate quality measurements. Besides, a new multivariate cumulative sum chart (MCUSUM) is introduced where the target shift mean is assumed to be a weighted sum of principal directions of the population covariance matrix. In practical problems, estimated parameters are needed and the properties of control charts differ from the case where the parameters are known in advance. In particular, it has been observed that the average run length (ARL), a performance indicator of the control charts, is larger when the estimated parameters are used. As a first contribution we provide a general and formal proof of the phenomenon. Also, to design an efficient 〖T 〗^2 or CUSUM chart with estimated parameters, a method to calculate or approximate the ARL function is necessarily needed. A commonly used approach consists in tabulating reference values using extensive Monte-Carlo simulation. By a different approach in thesis, an analytical approximation for the ARL function in univariate case is provided, especially in-control ARL function, which can help to directly set up control limits for different sample sizes of Phase I procedure instead of conducting complex simulation. / published_or_final_version / Statistics and Actuarial Science / Master / Master of Philosophy

published_or_final_version / abstract / toc / Industrial and Manufacturing Systems Engineering / Master / Master of Philosophy

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The geometric dimensioning and tolerancing concept of coaxiality is often required by design engineers for balance of rotating parts and precision mating parts. In current practice, it is difficult for manufacturers to measure coaxiality quickly and inexpensively. This study examines feasibility of a manually-operated, mechanical device combined with formulae to indicate coaxiality of a test specimen. The author designs, fabricates, and tests the system for measuring coaxiality of holes machined in a steel test piece. Gage Repeatability and Reproducibility (gage R&R) and univariate analysis of variance is performed in accordance with Measurement System Analysis published by AIAG. Results indicate significant design flaws exist in the current configuration of the device; observed values vary greatly with operator technique. Suggestions for device improvements conclude the research.

Orientador: Manoel Henrique Salgado / Banca: José de Souza Rodrigues / Banca: João Pedro Albino / Resumo: O propósito desta dissertação é analisar a implantação da ferramenta Controle Estatístico de Processo (CEP) para a gestão de operações de uma empresa do setor alimentício. Para tanto, realizou-se uma fundamentação que compreende: o Controle de Qualidade, a Variabilidade do Processo e o CEP. Esta fundamentação teórica apoiou o presente estudo de caso, consequentemente, foi possível descrever e discutir todas as etapas de aplicação da ferramenta no contexto de iplementação de um novo sistema de Gestão. Em adição, sugerir a proposta de um roteiro para auxílio na implantação da ferramenta CEP em processos de manufatura. Os resultados permitem constatar que as ferramentas que compõe um pacote corporativo podem não ser eficazes, quando esta não é analisada quanto à sua dimensão teórica de aplicabilidade no local a ser utilizado. Outro ponto constatado nos resultados é a necessidade de formalizar uma norma padrão de aplicabilidade de ferramentas de gestão, evitando a ocorrência de erros comuns de erros comuns, como, a não existência de um estudo para identificar não apenas a característica da qualidade, mas quais equipamentos ou pontos de operação devem ser monitorados pela ferramenta contida no Sistema de Gestão / Abstract: The purpose of this dissertation is to analize the implentation of the SPC (Statistical Process Control) for the management of operations in a food company. Furthermore, it was performer a theoretical review that includes: Quality Control, Process Variability and SPC. This theoretical review supported this case study, and it has possible to describe and discuss all the steps of deployment the tool in the new System of Management. In addition, to suggest a proposal of a guide to aid the implementation of the SPC in manufacturing processes. The results reveal that comprise a corporative guide may not be effective, when this is not analyzed in a techinical dimension of applicability on the local to be used. Moreover, the point observed in the results, all the System of Management need to formalize a standard applicatibility of management tools, avoiding common mistakes; for instance, non-existence of a study to identify which equipment or point of operatio must be monitored / Mestre

In this thesis, we first investigate the use of automated variance estimators in distribution-free statistical process control (SPC) charts for univariate autocorrelated processes. We introduce two variance estimators---the standardized time series overlapping area estimator and the so-called quick-and-dirty autoregressive estimator---that can be obtained from a training data set and used effectively with distribution-free SPC charts when those charts are applied to processes exhibiting nonnormal responses or correlation between successive responses. In particular, we incorporate the two estimators into DFTC-VE, a new distribution-free tabular CUSUM chart developed for autocorrelated processes; and we compare its performance with other state-of-the-art distribution-free SPC charts. Using either of the two variance estimators, the DFTC-VE outperforms its competitors in terms of both in-control and out-of-control average run lengths when all the competing procedures are tested on the same set of independently sampled realizations of selected autocorrelated processes with normal or nonnormal noise components. Next, we develop WDFTC, a wavelet-based distribution-free CUSUM chart for detecting shifts in the mean of a high-dimensional profile with noisy components that may exhibit nonnormality, variance heterogeneity, or correlation between profile components. A profile describes the relationship between a selected quality characteristic and an input (design) variable over the experimental region. Exploiting a discrete wavelet transform (DWT) of the mean in-control profile, WDFTC selects a reduced-dimension vector of the associated DWT components from which the mean in-control profile can be approximated with minimal weighted relative reconstruction error. Based on randomly sampled Phase I (in-control) profiles, the covariance matrix of the corresponding reduced-dimension DWT vectors is estimated using a matrix-regularization method; then the DWT vectors are aggregated (batched) so that the nonoverlapping batch means of the reduced-dimension DWT vectors have manageable covariances. To monitor shifts in the mean profile during Phase II operation, WDFTC computes a Hotelling's T-square--type statistic from successive nonoverlapping batch means and applies a CUSUM procedure to those statistics, where the associated control limits are evaluated analytically from the Phase I data. We compare WDFTC with other state-of-the-art profile-monitoring charts using both normal and nonnormal noise components having homogeneous or heterogenous variances as well as independent or correlated components; and we show that WDFTC performs well, especially for local shifts of small to medium size, in terms of both in-control and out-of-control average run lengths.

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Made available in DSpace on 2015-10-06T13:02:52Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-07-24. Added 1 bitstream(s) on 2015-10-06T13:19:23Z : No. of bitstreams: 1 000849258.pdf: 2226814 bytes, checksum: ca063d8bb02a6e7f91015b7d956c1ded (MD5) / O Brasil é o maior produtor mundial de cana-de-açúcar, devido a expansão de áreas cultivadas, a adubação mecanizada torna-se muito importante para o aumento do desempenho operacional nesta cultura, porém esta adubação pode demonstrar alguns problemas na distribuição de fertilizantes, como a não realização da caracterização dos fertilizantes por meio do ângulo de repouso, granulometria e densidade dos nutrientes, entre outros. Dessa forma, torna-se necessário o desenvolvimento de novas tecnologias que possibilitem uma melhora na aplicação de fertilizantes na cultura da cana-de-açúcar. À vista disso, um novo conceito de adubadora está em desenvolvimento considerada como protótipo, pois esta realiza aplicação individualizada de nitrogênio, fósforo e potássio proporcionando maior eficiência na distribuição destes em relação às outras adubadoras. Com este trabalho o objetivo foi avaliar aplicação mecanizada de N-P-K individualizada na cultura da cana-de-açúcar. O experimento foi desenvolvido no município de Matão em área de cana-de-açúcar pertencente à Fazenda Cascavel, possuindo 1,66 ha aproximadamente de área experimental. O delineamento experimental foi Inteiramente Casualizado (DIC), com três tratamentos e trinta repetições por tratamento. Este delineamento foi estabelecido conforme os critérios do controle de qualidade, sendo o monitoramento das variáveis realizado durante a operação de adubação. Ao final do período de avaliação foram coletados 90 pontos amostrais no total, sendo 30 pontos por tratamento. Os tratamentos foram: 1- Adubação mecanizada, sem aplicação de herbicida; 2- Operação conjugada (aplicação simultânea de herbicida e adubação); e 3- Duas operações (aplicação separada de herbicida e adubo). Concluiu-se que a melhor qualidade operacional por meio das cartas de controle foi o tratamento 3, sendo duas operações (aplicação separada de herbicida e adubo)... / The Brazil is the largest producer of sugarcane, due to expansion of cultivated areas, mechanized fertilizer becomes very important for the increase in operating performance in this culture, but this fertilization may show some problems in the distribution of fertilizers, so that when not performing the characterization of fertilizers through the angle of repose, particle size and density of nutrients, among other. Thus, it becomes necessary to develop new technologies that enable an improvement in the application of fertilizers in the cultivation of sugarcane. In view of this, a new concept of fertilizer in development considered as a prototype because this performs individualized application of nitrogen, phosphorus and potassium, providing greater efficiency in the distribution of these over other fertilizer machine. With this work the objective was to evaluate the mechanical application of NPK individualized culture of sugarcane. The experiment was conducted in the Matão municipality in the area of sugarcane belonging to the Fazenda Cascavel, possessing approximately 1.66 ha experimental area. The experimental design was completely randomized (DIC), with three treatments and thirty replications for treatment. This design was established according to the criteria of quality control, and monitoring of variables held during fertilization operation. At the end of the evaluation period were collected 90 sample points in total, with 30 points per treatment. The treatments were: 1- mechanized fertilized, without herbicide; 2- Operation combined (simultaneous application of herbicide and fertilizer); and 3- Two operations (separate application of herbicide and fertilizer). It was concluded that the best operational quality through control charts was the third treatment, two operations (separate application of herbicide and fertilizer) for presenting less variability. The right side of fertilizer machine was the best for having applied ...