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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Otimização de processos com respostas múltiplas e categóricas

Lucas, Cícero de Melo January 2007 (has links)
A presente dissertação aborda a otimização de processos industriais através da utilização de projeto de experimentos. Em experimentos planejados, variáveis de respostas são usualmente consideradas como normalmente distribuídas. No entanto, em algumas situações, tal suposição é violada; por exemplo, quando respostas expressam contagens, podendo assumir somente valores inteiros e não-negativos. Nesses casos, é mais provável que as respostas sigam uma distribuição de Poisson e, em sua modelagem, deve-se utilizar os modelos lineares generalizados (MLG), adequados para respostas da chamada família exponencial, à qual pertence a distribuição de Poisson. Se ainda persiste a dúvida quanto ao comportamento das respostas, o modelo de quase-verossimilhança também é uma alternativa possível. Esta dissertação apresenta a reanálise de um experimento, apresentado em Arriba (2005), onde algumas respostas são categóricas. Na análise original do experimento, respostas categóricas foram modeladas através de regressão dos mínimos quadrados ordinários, desconsiderando a violação do pressuposto de normalidade das respostas. Na reanálise aqui apresentada, as variáveis são corretamente abordadas usando-se os modelos lineares generalizados. Como o objetivo do trabalho de Arriba (2005) era a otimização de um processo descrito por múltiplas respostas, comparam-se os resultados da otimização mediante as duas estratégias de modelagem das respostas, além de se propor um método alternativo, mais simplificado, de otimização experimental. / This dissertation deals with the optimization of industrial processes using Design of Experiments. In designed experiments, response variables are often considered as normally distributed. However, in some situations, such assumption is violated; for example, when responses express counts, and only non-negative integers numbers may come up as outcomes. In these cases, it is likely that responses follow a Poisson distribution which is then modeled by generalized linear models (GLM), since such distribution is a member of the exponential family. If a question still holds on the responses behavior, their modeling through the quasi-likelihood method is another option that should be considered. This dissertation analyses an experiment performed by Arriba (2005), where some responses are of categorical nature. In the original analysis presented by Arriba (2005), categorical responses were modeled using ordinary least squares regression, violating the normality assumption associated with that method. In the analysis presented here, variables are appropriately modeled using GLM. Since the objective in Arriba (2005) was optimizing a multiresponse process, results from the two optimization processes are compared. In addition, an alternative experimental optimization method, simpler than the one in Arriba (2005), is also presented.
22

Otimização de processos com respostas múltiplas e categóricas

Lucas, Cícero de Melo January 2007 (has links)
A presente dissertação aborda a otimização de processos industriais através da utilização de projeto de experimentos. Em experimentos planejados, variáveis de respostas são usualmente consideradas como normalmente distribuídas. No entanto, em algumas situações, tal suposição é violada; por exemplo, quando respostas expressam contagens, podendo assumir somente valores inteiros e não-negativos. Nesses casos, é mais provável que as respostas sigam uma distribuição de Poisson e, em sua modelagem, deve-se utilizar os modelos lineares generalizados (MLG), adequados para respostas da chamada família exponencial, à qual pertence a distribuição de Poisson. Se ainda persiste a dúvida quanto ao comportamento das respostas, o modelo de quase-verossimilhança também é uma alternativa possível. Esta dissertação apresenta a reanálise de um experimento, apresentado em Arriba (2005), onde algumas respostas são categóricas. Na análise original do experimento, respostas categóricas foram modeladas através de regressão dos mínimos quadrados ordinários, desconsiderando a violação do pressuposto de normalidade das respostas. Na reanálise aqui apresentada, as variáveis são corretamente abordadas usando-se os modelos lineares generalizados. Como o objetivo do trabalho de Arriba (2005) era a otimização de um processo descrito por múltiplas respostas, comparam-se os resultados da otimização mediante as duas estratégias de modelagem das respostas, além de se propor um método alternativo, mais simplificado, de otimização experimental. / This dissertation deals with the optimization of industrial processes using Design of Experiments. In designed experiments, response variables are often considered as normally distributed. However, in some situations, such assumption is violated; for example, when responses express counts, and only non-negative integers numbers may come up as outcomes. In these cases, it is likely that responses follow a Poisson distribution which is then modeled by generalized linear models (GLM), since such distribution is a member of the exponential family. If a question still holds on the responses behavior, their modeling through the quasi-likelihood method is another option that should be considered. This dissertation analyses an experiment performed by Arriba (2005), where some responses are of categorical nature. In the original analysis presented by Arriba (2005), categorical responses were modeled using ordinary least squares regression, violating the normality assumption associated with that method. In the analysis presented here, variables are appropriately modeled using GLM. Since the objective in Arriba (2005) was optimizing a multiresponse process, results from the two optimization processes are compared. In addition, an alternative experimental optimization method, simpler than the one in Arriba (2005), is also presented.
23

Otimização de processos com respostas múltiplas e categóricas

Lucas, Cícero de Melo January 2007 (has links)
A presente dissertação aborda a otimização de processos industriais através da utilização de projeto de experimentos. Em experimentos planejados, variáveis de respostas são usualmente consideradas como normalmente distribuídas. No entanto, em algumas situações, tal suposição é violada; por exemplo, quando respostas expressam contagens, podendo assumir somente valores inteiros e não-negativos. Nesses casos, é mais provável que as respostas sigam uma distribuição de Poisson e, em sua modelagem, deve-se utilizar os modelos lineares generalizados (MLG), adequados para respostas da chamada família exponencial, à qual pertence a distribuição de Poisson. Se ainda persiste a dúvida quanto ao comportamento das respostas, o modelo de quase-verossimilhança também é uma alternativa possível. Esta dissertação apresenta a reanálise de um experimento, apresentado em Arriba (2005), onde algumas respostas são categóricas. Na análise original do experimento, respostas categóricas foram modeladas através de regressão dos mínimos quadrados ordinários, desconsiderando a violação do pressuposto de normalidade das respostas. Na reanálise aqui apresentada, as variáveis são corretamente abordadas usando-se os modelos lineares generalizados. Como o objetivo do trabalho de Arriba (2005) era a otimização de um processo descrito por múltiplas respostas, comparam-se os resultados da otimização mediante as duas estratégias de modelagem das respostas, além de se propor um método alternativo, mais simplificado, de otimização experimental. / This dissertation deals with the optimization of industrial processes using Design of Experiments. In designed experiments, response variables are often considered as normally distributed. However, in some situations, such assumption is violated; for example, when responses express counts, and only non-negative integers numbers may come up as outcomes. In these cases, it is likely that responses follow a Poisson distribution which is then modeled by generalized linear models (GLM), since such distribution is a member of the exponential family. If a question still holds on the responses behavior, their modeling through the quasi-likelihood method is another option that should be considered. This dissertation analyses an experiment performed by Arriba (2005), where some responses are of categorical nature. In the original analysis presented by Arriba (2005), categorical responses were modeled using ordinary least squares regression, violating the normality assumption associated with that method. In the analysis presented here, variables are appropriately modeled using GLM. Since the objective in Arriba (2005) was optimizing a multiresponse process, results from the two optimization processes are compared. In addition, an alternative experimental optimization method, simpler than the one in Arriba (2005), is also presented.
24

Controle estatístico de qualidade de irrigação e fertirrigação por gotejamento na cultura da uva

Klein, Márcio Roberto 20 February 2013 (has links)
Made available in DSpace on 2017-07-10T19:23:37Z (GMT). No. of bitstreams: 1 Marcio.pdf: 2681229 bytes, checksum: ea2c2a858c1d63340b780fc26ee571c3 (MD5) Previous issue date: 2013-02-20 / Irrigated agriculture has great potential for productivity. The proof is that the area for irrigated agriculture in the world, representing approximately 20 % of the total area destined to agriculture, is responsible for approximately 45 % of the total harvested. In order to maximize the profits of agricultural products, it is necessary to comply with various protocols of good practice, which include, in addition to maintaining a quality standard specific to the products, reducing environmental impact and generating benefits to communities involved in the agricultural production. Then, it is possible to achieve a more profitable niche market. To achieve the agricultural products standards required by the market, there must be a level of control in the processes of cultural practices in the water and fertilizer application. Statistical quality control processes were implemented in the industries of Japan after the Second World War and it is considered the tool responsible for the triumph of manufacturing, service and quality processes for the country. Quality control is perfectly adaptable for the agricultural production system. Therefore, this research aimed to assess the distribution of water and fertilizer in a drip irrigation system and determine the limits of statistical process and process capabilities in irrigation and fertigation under different pressures and concentrations of NPK (Nitrogen, Phosphorus and Potassium). The experiment was conducted in the municipality of Salto do Lontra, in a farm that participates in the Family Irrigation Project developed by Unioeste University. There were four inlet pressures: 150, 200, 250, and 300 kPa, combined with three NPK solution concentrations: 0, 200, and 400 mgL-1. In the evaluations, two methods were used for sampling, one with 16 points and another with 32 points. Using the average flow rate, CUC and CUD were calculated both methodologies. The classification of CUC was "excellent" for all assessments. Using CUD, 83.4 % of ratings were "excellent" with the sampling methodology with 16 points, and 97.3 % with the methodology of 32 points. None of the processes were considered acceptable for process use, when statistical control limits were calculated. The processes of irrigation and fertigation more suitable for improvement and consequent process capability increase were those with inlet pressures of 150 and 200 kPa. / A agricultura irrigada tem um grande potencial de produtividade. Prova disso é que a área destinada à agricultura irrigada no mundo, correspondente a cerca de 20 % da área total para a agricultura, e é responsável por aproximadamente 45 % do total colhido. Visando maximizar os lucros dos produtos agrícolas, é necessário cumprir diversos protocolos de boas práticas, que incluem, além de manter um padrão de qualidade específico dos produtos, reduzir os impactos ambientais e gerar benefícios sociais à s comunidades envolvidas na produção agrícola. Feito isso, é possível atingir um nicho de mercado mais lucrativo. Para atingir os padrões dos produtos agrícolas exigidos pelo mercado, deve haver um controle nos processos de tratos culturais na aplicação de água e fertilizantes. O controle estatístico de qualidade de processos passou a ser utilizado nas indústrias do Japão após a segunda guerra mundial e é considerada a ferramenta responsável pelo triunfo na produção de produtos, serviços e processos de qualidade. O controle de qualidade é perfeitamente adaptável ao sistema de produção agrícola. Diante disso, a realização desta pesquisa teve por objetivo avaliar a distribuição de água e fertilizante num sistema de irrigação por gotejamento e determinar os limites estatísticos de processo e as capacidades de processo na irrigação e fertirrigação submetidos a diferentes pressões e concentrações da solução de NPK (nitrogênio, fósforo e potássio). O experimento foi desenvolvido no município de Salto do Lontra, em uma propriedade rural participante do Projeto de Irrigação Familiar da Unioeste. Foram utilizadas quatro pressões de entrada: 150, 200, 250 e 300 kPa, combinadas com três concentrações de solução NPK: 0, 200 e 400 mgL-1. Nas avaliações, foram utilizadas duas metodologias de amostragem, uma com 16 e outra com 32 pontos. Com os valores médios de vazão, calculou-se o CUC e o CUD para ambas as metodologias. A classificação do CUC foi excelente para todas as avaliações; com o CUD, 83,4 % das avaliações foram excelentes com a metodologia de amostragem com 16 pontos e 97,3 % com a metodologia de 32 pontos. Nenhum dos processos obteve capacidade de processo aceitável para processo em uso, quando determinados os limites de controle estatístico. Os processos de irrigação e fertirrigação mais passíveis de melhora e consequente aumento de capacidade de processo foram com as pressões de entrada de 150 e 200 kPa.
25

Bezpečnost podnikové informatiky v souvislosti s ITIL / Information Security in the context of ITIL

Korous, Petr January 2011 (has links)
The diploma thesis discusses information security management in the context of ITIL framework. In the introductory part is explained the concept of information security, its importance and main goals. In subsequent chapters, the work aims to explore methodologies, frameworks and standards related to information security and internal control. Selected frameworks and models and described and compared with each other based on different criteria. The comparison is also one of the benefits of the work because similar topics which compare different models of internal control and information security are quite rare in the literature. The practical part of the thesis forms new methodology on basis of researched models and standards, including ISO 27000, ITIL and COBIT. This methodology provides a relatively simple way to evaluate the level of information security in an organization. It uses process capability model which is applied on selected company. Another benefit of the thesis is the developed methodology and its demonstration on a selected company.
26

Analýza zmetkovitosti ve výrobním procesu / Scrap Analysis in Manufacturing Process

Buriánková, Alena January 2019 (has links)
The master’s thesis is focused on the reduction of rejection rate in production of plastic bowls with the use of statistic methods. The theoretical part of this thesis describes among others Statistical Process Control, Process capability and types regulatory diagrams. The basis for the practical part is data collection over a certain period of production, from which the percentage of the rejection rate is evaluated. Experiments and corrective actions are designed to improve the process and thereby reduce scrap.
27

Statistické vlastnosti regulačních diagramů a modelů způsobilosti / Statistical properties of control charts and capability models

Vidová, Katarína January 2020 (has links)
The diploma thesis is focused on process stability and capability assessment. It describes certain types of control charts, basic capability indices as well as Box-Cox transformation. The practical part of the study is concerned with applying control charts on generated data and consequently on real data. By this, it focuses on comparing various methods of estimating sample standard deviation and on the impact of non-compliance with the assumption of normal distribution of process variable on process stability and capability assessment.
28

Statistická podpora procesu řízení firmy / Statistical support of the company management process

Kubíček, Jan January 2021 (has links)
Master’s thesis describes statistical process control as a support for company management. Statistical process control methods and tools are introduced. Requirements for automotive industry are stated specifically for IATF 16949 standard and VDA 6.3 process audit method. Thesis presents current state in company Sanmina-SCI Czech Republic s.r.o regarding statistical regulation. Applies statistical process controls into the new process considering automotive requirements. It is all happening together with a new business introduction of automotive customer.
29

Matematické modely způsobilosti procesu / Mathematical Models of Process Capability

Horník, Petr January 2015 (has links)
Firstly, we deal with the verification of normality and other necessary prerequisites needed in this thesis. We also introduce transformations to converse non-normally distributed data to normal and continue with capability analysis. We describe the design of control charts, useful tools to assess process stability. They help us to eliminate assignable causes and leave only chance causes in process. We obtain process in control state. Finally, we introduce both capability and performance ratios for both normal and non-normal data, and analyse some of their properties. At the end of the thesis, we prove acquired knowledge by performing capability analysis of real process.
30

Metriky procesů vývoje softwaru / Software Development Processes Metrics

Verner, Jan January 2009 (has links)
The importance of processes is growing. Processes are integrated into many areas of human work, where they help to organize all activities. This thesis aims on statistical approach to process behavior analysis. There are mentioned the basic process management issues in the beginning of this thesis. The main focus is on the techniques used during process analysis. There are mentioned approaches that are used to easily and effectively assess process behavior using process behavior charts and how to deduce proper steps from the analysis results to improve the process. The last part of this thesis is dedicated to practical analysis of real process behavior data using implemented solution. The results show common usability of statistical methods and approaches to process analysis.

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