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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.
1

Multi criteria risk analysis of a subsea BOP system

Okonji, Stephen Chiedu January 2015 (has links)
The Subsea blowout preventer (BOP) which is latched to a subsea wellhead is one of several barriers in the well to prevent kicks and blowouts and it is the most important and critical equipment, as it becomes the last line of protection against blowout. The BOP system used in Subsea drilling operations is considered a Safety – Critical System, with a high severity consequence following its failure. Following past offshore blowout incidents such as the most recent Macondo in the Gulf of Mexico, there have been investigations, research, and improvements sought for improved understanding of the BOP system and its operation. This informs the need for a systematic re-evaluation of the Subsea BOP system to understand its associated risk and reliability and identify critical areas/aspects/components. Different risk analysis techniques were surveyed and the Failure modes effect and criticality analysis (FMECA) selected to be used to drive the study in this thesis. This is due to it being a simple proven cost effective process that can add value to the understanding of the behaviours and properties of a system, component, software, function or other. The output of the FMECA can be used to inform or support other key engineering tasks such as redesigning, enhanced qualification and testing activity or maintenance for greater inherent reliability and reduced risk potential. This thesis underscores the application of the FMECA technique to critique associated risk of the Subsea BOP system. System Functional diagrams was developed with boundaries defined, a FMECA were carried out and an initial select list of critical component failure modes identified. The limitations surrounding the confidence of the FMECA failure modes ranking outcome based on Risk priority number (RPN) is presented and potential variations in risk interpretation are discussed. The main contribution in this thesis is an innovative framework utilising Multicriteria decision making (MCDA) analysis techniques with consideration of fuzzy interval data is applied to the Subsea BOP system critical failure modes from the FMECA analysis. It utilised nine criticality assessment criteria deduced from expert consultation to obtain a more reliable ranking of failure modes. The MCDA techniques applied includes the technique for order of Preference for similarity to the Ideal Solution (TOPSIS), Fuzzy TOPSIS, TOPSIS with interval data, and Preference Ranking Organization Method for Enrichment of Evaluations (PROMETHEE). The outcome of the Multi-criteria analysis of the BOP system clearly shows failures of the Wellhead connector, LMRP hydraulic connector and Control system related failure as the Top 3 most critical failure with respect to a well control. The critical failure mode and components outcome from the analysis in this thesis is validated using failure data from industry database and a sensitivity analysis carried out. The importance of maintenance, testing and redundancy to the BOP system criticality was established by the sensitivity analysis. The potential for MCDA to be used for more specific analysis of criteria for a technology was demonstrated. Improper maintenance, inspection, testing (functional and pressure) are critical to the BOP system performance and sustenance of a high reliability level. Material selection and performance of components (seals, flanges, packers, bolts, mechanical body housings) relative to use environment and operational conditions is fundamental to avoiding failure mechanisms occurrence. Also worthy of notice is the contribution of personnel and organisations (by way of procedures to robustness and verification structure to ensure standard expected practices/rules are followed) to failures as seen in the root cause discussion. OEMs, operators and drilling contractors to periodically review operation scenarios relative to BOP system product design through the use of a Failure reporting analysis and corrective action system. This can improve design of monitoring systems, informs requirement for re-qualification of technology and/or next generation designs. Operations personnel are to correctly log in failures in these systems, and responsible Authority to ensure root cause analysis is done to uncover underlying issue initiating and driving failures.
2

Comparação entre os métodos Fuzzy TOPSIS e Fuzzy AHP no apoio à tomada de decisão para seleção de fornecedores / A comparative analysis of the methods Fuzzy TOPSIS and Fuzzy AHP to supplier selection

Lima Junior, Francisco Rodrigues 25 February 2013 (has links)
A seleção de fornecedores tem impacto significante no custo e na qualidade de produtos manufaturados. Por isso, a seleção de fornecedores passou a ser vista como uma atividade bastante crítica para o desempenho da empresa compradora. Muitos estudos da literatura propõem o uso dos métodos multicritério fuzzy TOPSIS (Technique for Order of Preference by Similarity to Ideal Solution) e fuzzy AHP (Analytic Hierarchy Process) para apoiar a seleção de fornecedores. Contudo, não são encontrados estudos que avaliem o desempenho destes métodos quando usados neste domínio de problema. Diante desta lacuna, este estudo compara os métodos fuzzy TOPSIS (CHEN, 2000) e fuzzy AHP (CHANG, 1996) no apoio à seleção de fornecedores. Esta pesquisa utiliza uma abordagem quantitativa descritiva empírica, baseada em modelagem e simulação. Os métodos fuzzy TOPSIS e fuzzy AHP foram aplicados em um caso ilustrativo de seleção de fornecedores. O desempenho dos fornecedores e o peso dos critérios foram avaliados por um especialista de uma empresa. Modelos de simulação foram implementados usando MATLAB® e aplicados na seleção de fornecedores de uma empresa de uma cadeia de suprimentos automotiva. Cinco fornecedores foram avaliados em relação à qualidade, custo, entrega, perfil e relacionamento. O peso dos critérios e o desempenho dos fornecedores foi avaliado por meio da opinião de um especialista da empresa. Posteriormente, os métodos fuzzy TOPSIS e fuzzy AHP foram comparados em relação à capacidade de apoiar a decisão em grupo, qualificação de fornecedores, escolha final de fornecedores, situações de compra e modelagem de decisões sob incerteza. A eficiência dos métodos em relação à complexidade computacional e à interação requerida com o usuário também foi comparada. Os resultados mostraram que o fuzzy TOPSIS é mais flexível e mais adequado que o fuzzy AHP para modelar diferentes tipos de cenários de seleção de fornecedores. A realização desta discussão é sugerida por Ertugrul e Karakasoglu (2008), e é relevante para ajudar pesquisadores e gestores na escolha de abordagens efetivas para lidar com diferentes cenários de seleção de fornecedores. / Supplier selection has a significant influence on the cost, quality and delivery of products of the buying company. Therefore, supplier selection has become a very critical activity to the performance of the buying company. Several studies presented in the literature propose the use of fuzzy TOPSIS (Technique for Order of Preference by Similarity to Ideal Solution) and fuzzy AHP (Analytic Hierarchy Process) to aid the decision process of supplier selection. However, there are no comparative studies of these two methods when applied to the problem of supplier selection. Thus, this paper presents a comparative analysis of the methods fuzzy TOPSIS (Chen, 2000) and fuzzy AHP (Chang, 1996) applied to the problem of supplier selection. A descriptive quantitative approach was adopted as the research method. Algorithms of the methods fuzzy TOPSIS and fuzzy AHP were developed in Matlab© and applied to the selection of suppliers of a company in the automotive production chain. Five suppliers were evaluated regarding quality of conformance, cost, delivery, profile and relationship. The weight of the criteria and the performance of the suppliers were evaluated by specialist opinion from the studied company. The methods Fuzzy TOPSIS e Fuzzy AHP were compared in terms of ability to support the group decision, supplier qualification, final choice of suppliers, buying situations and modeling decisions under uncertainty. The efficiency of the methods with respect to computational complexity and the required user interaction was also compared. The comparative analysis shows that Fuzzy TOPSIS presents better than Fuzzy AHP performance, especially in scenarios in wich many alternatives are evaluated. Thus, Fuzzy TOPSIS is more flexible and appropriate than Fuzzy AHP to deal with supplier selection problem. This paper presents a new study, comparing the methods Fuzzy TOPSIS and Fuzzy AHP. As commented by Ertugrul and Karakasoglu (2008), a study such as this can contribute to the advance of knowledge, helping researchers and practitioners choosing more effective approaches to supplier selection.
3

Comparação entre os métodos Fuzzy TOPSIS e Fuzzy AHP no apoio à tomada de decisão para seleção de fornecedores / A comparative analysis of the methods Fuzzy TOPSIS and Fuzzy AHP to supplier selection

Francisco Rodrigues Lima Junior 25 February 2013 (has links)
A seleção de fornecedores tem impacto significante no custo e na qualidade de produtos manufaturados. Por isso, a seleção de fornecedores passou a ser vista como uma atividade bastante crítica para o desempenho da empresa compradora. Muitos estudos da literatura propõem o uso dos métodos multicritério fuzzy TOPSIS (Technique for Order of Preference by Similarity to Ideal Solution) e fuzzy AHP (Analytic Hierarchy Process) para apoiar a seleção de fornecedores. Contudo, não são encontrados estudos que avaliem o desempenho destes métodos quando usados neste domínio de problema. Diante desta lacuna, este estudo compara os métodos fuzzy TOPSIS (CHEN, 2000) e fuzzy AHP (CHANG, 1996) no apoio à seleção de fornecedores. Esta pesquisa utiliza uma abordagem quantitativa descritiva empírica, baseada em modelagem e simulação. Os métodos fuzzy TOPSIS e fuzzy AHP foram aplicados em um caso ilustrativo de seleção de fornecedores. O desempenho dos fornecedores e o peso dos critérios foram avaliados por um especialista de uma empresa. Modelos de simulação foram implementados usando MATLAB® e aplicados na seleção de fornecedores de uma empresa de uma cadeia de suprimentos automotiva. Cinco fornecedores foram avaliados em relação à qualidade, custo, entrega, perfil e relacionamento. O peso dos critérios e o desempenho dos fornecedores foi avaliado por meio da opinião de um especialista da empresa. Posteriormente, os métodos fuzzy TOPSIS e fuzzy AHP foram comparados em relação à capacidade de apoiar a decisão em grupo, qualificação de fornecedores, escolha final de fornecedores, situações de compra e modelagem de decisões sob incerteza. A eficiência dos métodos em relação à complexidade computacional e à interação requerida com o usuário também foi comparada. Os resultados mostraram que o fuzzy TOPSIS é mais flexível e mais adequado que o fuzzy AHP para modelar diferentes tipos de cenários de seleção de fornecedores. A realização desta discussão é sugerida por Ertugrul e Karakasoglu (2008), e é relevante para ajudar pesquisadores e gestores na escolha de abordagens efetivas para lidar com diferentes cenários de seleção de fornecedores. / Supplier selection has a significant influence on the cost, quality and delivery of products of the buying company. Therefore, supplier selection has become a very critical activity to the performance of the buying company. Several studies presented in the literature propose the use of fuzzy TOPSIS (Technique for Order of Preference by Similarity to Ideal Solution) and fuzzy AHP (Analytic Hierarchy Process) to aid the decision process of supplier selection. However, there are no comparative studies of these two methods when applied to the problem of supplier selection. Thus, this paper presents a comparative analysis of the methods fuzzy TOPSIS (Chen, 2000) and fuzzy AHP (Chang, 1996) applied to the problem of supplier selection. A descriptive quantitative approach was adopted as the research method. Algorithms of the methods fuzzy TOPSIS and fuzzy AHP were developed in Matlab© and applied to the selection of suppliers of a company in the automotive production chain. Five suppliers were evaluated regarding quality of conformance, cost, delivery, profile and relationship. The weight of the criteria and the performance of the suppliers were evaluated by specialist opinion from the studied company. The methods Fuzzy TOPSIS e Fuzzy AHP were compared in terms of ability to support the group decision, supplier qualification, final choice of suppliers, buying situations and modeling decisions under uncertainty. The efficiency of the methods with respect to computational complexity and the required user interaction was also compared. The comparative analysis shows that Fuzzy TOPSIS presents better than Fuzzy AHP performance, especially in scenarios in wich many alternatives are evaluated. Thus, Fuzzy TOPSIS is more flexible and appropriate than Fuzzy AHP to deal with supplier selection problem. This paper presents a new study, comparing the methods Fuzzy TOPSIS and Fuzzy AHP. As commented by Ertugrul and Karakasoglu (2008), a study such as this can contribute to the advance of knowledge, helping researchers and practitioners choosing more effective approaches to supplier selection.
4

Risk-based reliability assessment of subsea control module for offshore oil and gas production

Umofia, Anietie Nnana January 2014 (has links)
Offshore oil and gas exploitation is principally conducted using dry or wet tree systems, otherwise called the subsea Xmas tree system. Due to the shift to deeper waters, subsea production system (SPS) has come to be a preferred technology with attendant economic benefits. At the centre of the SPS is the subsea control module (SCM), responsible for the proper functioning and monitoring of the entire system. With increasing search for hydrocarbons in deep and ultra-deepwaters, the SCM system faces important environmental, safety and reliability challenges and little research has been done in this area. Analysis of the SCM reliability then becomes very fundamental due to the huge cost associated with failure. Several tools are available for this analysis, but the FMECA stands out due to its ability to not only provide failure data, but also showcase the system’s failure modes and mechanisms associated with the subsystems and components being evaluated. However, the technique has been heavily challenged in various literatures for several reasons. To close this gap, a novel multi-criteria approach is developed for the analysis and ranking of the SCM failures modes. This research specifically focusses on subsea tree-mounted electro-hydraulic (E-H) SCM responsible for the underwater control of oil and gas production. A risk identification of the subsea control module is conducted using industry experts. This is followed by a comprehensive component based FMECA analysis of the SCM conducted with the conventional RPN technique, which reveals the most critical failure modes for the SCM. A novel framework is developed using multi-criteria fuzzy TOPSIS methodology and applied to the most critical failure modes obtained from the FMECA evaluation using unconventional parameters. Finally, a validation of these results is performed using a stochastic input evaluation and SCM failure data obtained from the offshore industry standard reliability database, OREDA.
5

Risk-based Reliability Assessment of Subsea Control module for Offshore Oil and Gas production

Umofia, Anietie Nnana 09 1900 (has links)
Offshore oil and gas exploitation is principally conducted using dry or wet tree systems, otherwise called the subsea Xmas tree system. Due to the shift to deeper waters, subsea production system (SPS) has come to be a preferred technology with attendant economic benefits. At the centre of the SPS is the subsea control module (SCM), responsible for the proper functioning and monitoring of the entire system. With increasing search for hydrocarbons in deep and ultra-deepwaters, the SCM system faces important environmental, safety and reliability challenges and little research has been done in this area. Analysis of the SCM reliability then becomes very fundamental due to the huge cost associated with failure. Several tools are available for this analysis, but the FMECA stands out due to its ability to not only provide failure data, but also showcase the system’s failure modes and mechanisms associated with the subsystems and components being evaluated. However, the technique has been heavily challenged in various literatures for several reasons. To close this gap, a novel multi-criteria approach is developed for the analysis and ranking of the SCM failures modes. This research specifically focusses on subsea tree-mounted electro-hydraulic (E-H) SCM responsible for the underwater control of oil and gas production. A risk identification of the subsea control module is conducted using industry experts. This is followed by a comprehensive component based FMECA analysis of the SCM conducted with the conventional RPN technique, which reveals the most critical failure modes for the SCM. A novel framework is developed using multi-criteria fuzzy TOPSIS methodology and applied to the most critical failure modes obtained from the FMECA evaluation using unconventional parameters. Finally, a validation of these results is performed using a stochastic input evaluation and SCM failure data obtained from the offshore industry standard reliability database, OREDA.
6

Uso de método multicritério para seleção de estratégia de reconversão industrial em uma refinaria de petróleo

Caetani, Alberto Pavlick January 2014 (has links)
Este trabalho apresenta o processo de seleção de estratégia de reconversão industrial de uma pequena refinaria de petróleo no Sul do Brasil através da aplicação de uma modelagem integrada, utilizando um método multicriterial e programação matemática. Neste estudo foram identificadas linhas de negócio potencialmente aplicáveis à realidade da companhia e definido um conjunto de critérios de análise abrangendo as três dimensões da sustentabilidade empresarial: econômica, social e ambiental. Com base na avaliação da importância relativa de cada critério, atribuída por um grupo de decisores, e no desempenho das linhas de negócio em cada um dos critérios, foi aplicado método fuzzy TOPSIS para análise e ordenação das linhas de negócio. As informações resultantes desta análise, juntamente com dados econômicos objetivos, foram utilizadas em um modelo de programação linear inteira para avaliar portfólios viáveis de linhas de negócio, identificando estratégias candidatas à implementação na refinaria. O desempenho global de cada estratégia candidata, obtido mediante agregação dos desempenhos individuais das linhas de negócio e calculado conforme método fuzzy TOPSIS, foi analisado através de ferramentas gráficas, de modo a gerar elementos para subsidiar a seleção da melhor estratégia de reconversão. Os resultados obtidos demonstraram a eficiência da abordagem proposta, no sentido de facilitar o entendimento e a exploração da situação problema e, assim, oferecer um adequado suporte à tomada de decisão. / This dissertation presents a selection process of industrial reconversion strategy in a small oil refinery in southern Brazil by applying an integrated modeling approach, using a multicriteria and a mathematical programming method. Potentially performing business lines were identified, as well a set of criteria covering the three dimensions of corporate sustainability: economic, social and environmental. Based on the relative importance evaluation of each criteria given by a group of decision-makers, and on performance of the business lines in each of the criteria, fuzzy TOPSIS method was applied for analysis and sorting of business lines. The information resulting from this analysis, along with objective economic data, were used in integer linear programming model to evaluate effective portfolios of business lines, identifying candidate strategies to implement in the refinery. Fuzzy TOPSIS is used to generate overall performance scores of each candidate strategy, aggregating the individual performance of the business lines. The sustainability assessment was analyzed through graphical tools in order to generate information to support the selection of the best strategy for the industrial reconversion. The results demonstrated the efficiency of the proposed approach to facilitate the understanding and exploitation of the problem situation and thus offer adequate support to decision making.
7

Um modelo de portf?lio para gest?o estrat?gica de compras hospitalares

Medeiros, Marlene 26 November 2015 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-06-03T23:32:21Z No. of bitstreams: 1 MarleneMedeiros_DISSERT.pdf: 3360629 bytes, checksum: 0fbf8e4ba72f42dba8927087b2e8b54f (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-06-07T00:13:50Z (GMT) No. of bitstreams: 1 MarleneMedeiros_DISSERT.pdf: 3360629 bytes, checksum: 0fbf8e4ba72f42dba8927087b2e8b54f (MD5) / Made available in DSpace on 2016-06-07T00:13:50Z (GMT). No. of bitstreams: 1 MarleneMedeiros_DISSERT.pdf: 3360629 bytes, checksum: 0fbf8e4ba72f42dba8927087b2e8b54f (MD5) Previous issue date: 2015-11-26 / O presente estudo, baseado no modelo te?rico de portf?lio de compras proposto por Kraljic (1983), apresenta um modelo de portf?lio de compras voltado para gest?o de compras hospitalares, por meio da aplica??o do m?todo de decis?o multicrit?rio Fuzzy-TOPSIS. Para fins de exemplifica??o do m?todo, a pesquisa foi aplicada em um Hospital de grande porte localizado em Natal/RN e teve como amostra doze itens de compras. Os itens foram avaliados pelo grupo de decisores nas dimens?es de import?ncia da compra e complexidade de fornecimento, sendo cada dimens?o composta por quatro crit?rios. Por meio da utiliza??o do m?todo Fuzzy-TOPSIS e de regras de decis?o, os itens foram classificados entre as categorias: estrat?gicos, gargalos, alavancagem e n?o-cr?ticos. O resultado dessa etapa identificou tr?s itens estrat?gicos, seis itens gargalos, um item de alavancagem e dois itens n?o-cr?ticos. Para os tr?s itens classificados como estrat?gicos, foi aplicado o m?todo Fuzzy-TOPSIS visando a identificar o posicionamento estrat?gico do Hospital em rela??o aos fornecedores desses itens, a partir da avalia??o das dimens?es for?a do mercado fornecedor e for?a da empresa compradora, sendo cada uma composta por quatro crit?rios. Nessa etapa, foi identificada uma postura de balanceamento das for?as. Conclui-se a efetividade da ferramenta de portf?lio de compras para gest?o hospitalar, proporcionando uma vis?o mais clara das caracter?sticas, inerentes ao processo de compras nesse contexto complexo. O m?todo Fuzzy-TOPSIS apresentou-se como uma ferramenta flex?vel, capaz de lidar com problemas de classifica??o, gerando resultados satisfat?rios e contribuindo para a tomada de decis?o.
8

Uso de método multicritério para seleção de estratégia de reconversão industrial em uma refinaria de petróleo

Caetani, Alberto Pavlick January 2014 (has links)
Este trabalho apresenta o processo de seleção de estratégia de reconversão industrial de uma pequena refinaria de petróleo no Sul do Brasil através da aplicação de uma modelagem integrada, utilizando um método multicriterial e programação matemática. Neste estudo foram identificadas linhas de negócio potencialmente aplicáveis à realidade da companhia e definido um conjunto de critérios de análise abrangendo as três dimensões da sustentabilidade empresarial: econômica, social e ambiental. Com base na avaliação da importância relativa de cada critério, atribuída por um grupo de decisores, e no desempenho das linhas de negócio em cada um dos critérios, foi aplicado método fuzzy TOPSIS para análise e ordenação das linhas de negócio. As informações resultantes desta análise, juntamente com dados econômicos objetivos, foram utilizadas em um modelo de programação linear inteira para avaliar portfólios viáveis de linhas de negócio, identificando estratégias candidatas à implementação na refinaria. O desempenho global de cada estratégia candidata, obtido mediante agregação dos desempenhos individuais das linhas de negócio e calculado conforme método fuzzy TOPSIS, foi analisado através de ferramentas gráficas, de modo a gerar elementos para subsidiar a seleção da melhor estratégia de reconversão. Os resultados obtidos demonstraram a eficiência da abordagem proposta, no sentido de facilitar o entendimento e a exploração da situação problema e, assim, oferecer um adequado suporte à tomada de decisão. / This dissertation presents a selection process of industrial reconversion strategy in a small oil refinery in southern Brazil by applying an integrated modeling approach, using a multicriteria and a mathematical programming method. Potentially performing business lines were identified, as well a set of criteria covering the three dimensions of corporate sustainability: economic, social and environmental. Based on the relative importance evaluation of each criteria given by a group of decision-makers, and on performance of the business lines in each of the criteria, fuzzy TOPSIS method was applied for analysis and sorting of business lines. The information resulting from this analysis, along with objective economic data, were used in integer linear programming model to evaluate effective portfolios of business lines, identifying candidate strategies to implement in the refinery. Fuzzy TOPSIS is used to generate overall performance scores of each candidate strategy, aggregating the individual performance of the business lines. The sustainability assessment was analyzed through graphical tools in order to generate information to support the selection of the best strategy for the industrial reconversion. The results demonstrated the efficiency of the proposed approach to facilitate the understanding and exploitation of the problem situation and thus offer adequate support to decision making.
9

Uso de método multicritério para seleção de estratégia de reconversão industrial em uma refinaria de petróleo

Caetani, Alberto Pavlick January 2014 (has links)
Este trabalho apresenta o processo de seleção de estratégia de reconversão industrial de uma pequena refinaria de petróleo no Sul do Brasil através da aplicação de uma modelagem integrada, utilizando um método multicriterial e programação matemática. Neste estudo foram identificadas linhas de negócio potencialmente aplicáveis à realidade da companhia e definido um conjunto de critérios de análise abrangendo as três dimensões da sustentabilidade empresarial: econômica, social e ambiental. Com base na avaliação da importância relativa de cada critério, atribuída por um grupo de decisores, e no desempenho das linhas de negócio em cada um dos critérios, foi aplicado método fuzzy TOPSIS para análise e ordenação das linhas de negócio. As informações resultantes desta análise, juntamente com dados econômicos objetivos, foram utilizadas em um modelo de programação linear inteira para avaliar portfólios viáveis de linhas de negócio, identificando estratégias candidatas à implementação na refinaria. O desempenho global de cada estratégia candidata, obtido mediante agregação dos desempenhos individuais das linhas de negócio e calculado conforme método fuzzy TOPSIS, foi analisado através de ferramentas gráficas, de modo a gerar elementos para subsidiar a seleção da melhor estratégia de reconversão. Os resultados obtidos demonstraram a eficiência da abordagem proposta, no sentido de facilitar o entendimento e a exploração da situação problema e, assim, oferecer um adequado suporte à tomada de decisão. / This dissertation presents a selection process of industrial reconversion strategy in a small oil refinery in southern Brazil by applying an integrated modeling approach, using a multicriteria and a mathematical programming method. Potentially performing business lines were identified, as well a set of criteria covering the three dimensions of corporate sustainability: economic, social and environmental. Based on the relative importance evaluation of each criteria given by a group of decision-makers, and on performance of the business lines in each of the criteria, fuzzy TOPSIS method was applied for analysis and sorting of business lines. The information resulting from this analysis, along with objective economic data, were used in integer linear programming model to evaluate effective portfolios of business lines, identifying candidate strategies to implement in the refinery. Fuzzy TOPSIS is used to generate overall performance scores of each candidate strategy, aggregating the individual performance of the business lines. The sustainability assessment was analyzed through graphical tools in order to generate information to support the selection of the best strategy for the industrial reconversion. The results demonstrated the efficiency of the proposed approach to facilitate the understanding and exploitation of the problem situation and thus offer adequate support to decision making.
10

Utveckling av arbetsprocess för effektivare produktutveckling : Tillämpad på standardisering av helautomatiskt snabbfäste till hjullastare

Clark, Eric, Olsson, David January 2021 (has links)
För att vara konkurrenskraftiga på marknaden tvingas företag utveckla nya strategier för produktutveckling, som kan anpassas till allt högre kundbehov. Syftet med detta arbete var att effektivisera produktutvecklingen för företag inom tillverkningsindustrin. Målet var att utveckla en effektiv arbetsprocess för produktutveckling samt att tillämpa processen på ett projekt, där ett helautomatiskt snabbfäste till mindre hjullastare skulle standardiseras till företaget OilQuick.Examensarbetet delades in i två delar. Den första delen behandlar skapandet av arbetsprocessen. Denna grundas i befintlig forskning och identifierades genom en litteraturstudie. Den andra delen behandlar tillämpning av arbetsprocessen på standardiseringen av snabbfästet till hjullastare. Data och kunskap till arbetet samlades in genom marknadsundersökningar, studiebesök, möten med kunder och Reverse Engineering. Kundkraven rangordnades med Best-worst metoden och översattes till tekniska produktegenskaper med Kvalitetshuset.Tre koncept genererades i Autodesk Inventor utifrån kraven och produktegenskaperna, samt datan som framkom av Reverse Engineering och marknadsundersökningen. Enligt kundkravet behövde det färdiga snabbfästet passa minst fyra olika hjullastarmodeller i viktklassen fem till åtta ton. Detta medförde att alla tre koncepten modulbaserades, både för att underlätta eventuella modifikationer mellan hjullastarmodellerna och för att minimera antalet detaljer som behövde modifieras. Alla tre konceptens redskapsgrindar hade standardiserade mått som passade de undersökta hjullastarmodeller. Det koncept som bäst uppfyllde kundkraven utvärderades med Fuzzy TOPSIS metoden. Det slutgiltiga konceptet justerades utifrån kundens önskemål innan det färdiga resultatet presenterades.Resultatet visade att arbetsprocessen var effektiv; Reverse Engineering och samarbetet med kunden gav en inblick i problematiken och förståelse för produkten, Best-worst metoden gjorde att rangordningen av kraven gick snabbt utan att minska på pålitligheten och Fuzzy TOPSIS metoden effektiviserade konceptvalet samtidigt som alla inblandades åsikter blev hörda. För att effektivisera produktutvecklingen ytterligare bör fler metoder undersökas alternativt utvecklas.Konceptförslagen som konstruerades påvisade att det är möjligt att standardisera gränssnittet mellan hjullastare och redskap. Genom modulärkonstruktion kunde snabbfästet anpassas till fyra olika hjullastarmodeller. Innan vidareutveckling av snabbfästet bör fler hjullastare mätas upp och studeras. / In order to be competitive in the market, companies are forced to develop new strategies that can be adapted to ever-increasing customer requirements. The purpose of the work was to streamline product development for companies in the manufacturing industry. The objective was to develop an efficient work process for product development and apply the process to a project where a standardized fully automatic quick coupler for smaller wheel loaders would be developed for the company OilQuick.The thesis was divided into two parts. The first part deals with the development of a work process based on existing research. The second part deals with the application of the work process. Data for the application was collected through market research, meetings with customers and Reverse Engineering. Customer requirements were ranked using the Best-worst method and translated into technical specifications using the method QFD (House of Quality).Three concepts were generated based on the resulting requirements from the QFD. According to the customer requirements, the quick coupler had to be compliant with at least four different wheel loader brands in the weight span from five to eight tons. This meant that all three concepts were based on modular design, both to facilitate modifications between the wheel loader brads and to minimize the number of details that needed to be modified. All three of the concept's attachment brackets had standardized dimensions that fitted all examined wheel loader models. To determine which concept that best met the customer requirements the Fuzzy TOPSIS method was used. The final concept was adjusted based on OilQuick's requirements before the finished result was presented.The results showed that the work process was efficient and reliable and that the developed concept proposal indicates that it is possible for the company to standardize the interface between wheel loaders and attachments. With modular design the quick coupler can be adapted to the wheel loader brands that were studied. To ensure that the quick coupler can be applied to a larger variety of wheel loaders, it is necessary to examine and take measurements of more wheel loader brands before further development.

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