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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

Implementing Lean Production : A pre study conducted at Strålfors Svenska AB

Basha, Ari, Toweny, Mostafa January 2012 (has links)
The concept Lean Production has nowadays become an accepted paradigm in several industries and it has become a fundamental part of manufacturing companies, as it seeks to reduce waste and deliver a high customer value. Lean Production is a technique that is a highly efficient manufacturing practice that helps organizations to carry on a competitive advantage. The concept works as a system of methods and measures which when combined have the potential to carry about a lean manufacturing. The objective of this research is to investigate how Strålfors Svenska Card can succeed in carrying out changes in their production in order to reduce waste, with reference to Lean Production. The study starts with a brief historical review about lean production, which is followed by a theoretical framework with useful concepts to adapt. The theoretical frameworks used in this research are: Lean House, “4P” Model, Lead the Change, Culture, Processes and Performance Measurements. The main research question of this thesis is: What are the main barriers for a successful lean implementation in Strålfors Svenska AB? Subsequently, the main research question was broken down to four sub questions. These are: How developed and mature in the organization are process methods? How are performance measurements employed? Which role does standardization, such as availability of tools, have? Which role do soft aspects, such as culture and values, play in understanding concepts?  Strålfors Svenska Card has to build a good platform in order to success with their implementation of lean production. Moreover, it means that the organization has to focus on developing necessary critical factors that are in the guideline with lean production. The researchers has used observations, interviews, surveys and value stream mapping in order to collect necessary data.
2

Implementação de infraestrutura laboratorial para análise operacional e capacitação em sistemas híbridos para geração de eletricidade / Implementation of Laboratory Infrastructure for Operational Analysis and Capacity Building in Hybrid Systems for Electricity Generation,

Souza, Kauê José Felipe Novaes Candido de 24 May 2018 (has links)
Este trabalho apresenta o processo de ampliação da infraestrutura laboratorial de minirredes e sistemas híbridos do Laboratório de Sistemas Fotovoltaicos do Instituto de Energia e Ambiente da Universidade de São Paulo, (LSF-IEE/USP). O trabalho também contempla uma revisão do estado da arte de sistemas híbridos e minirredes, apresentando principalmente os aspectos técnicos, como formas de acoplamento, e interações com a rede elétrica de distribuição. Descrevem-se os sistemas híbridos presentes no LSF e a infraestrutura para sua interconexão. Posteriormente são realizados os processos de comissionamento e testes operacionais da interconexão dos sistemas híbridos entre si e com a rede elétrica. Ao final é proposto um curso de aperfeiçoamento em minirredes e sistemas híbridos utilizando a infraestrutura presente no LSF. / This work presents the expansion of the micro-grid and hybrid systems infrastructure at the Laboratory of Photovoltaic Systems of the Institute of Energy and Environment at the University of São Paulo (LSF-IEE / USP). The work also presents a review of the state of the art of hybrid systems and micro-grid, presenting mainly the technical aspects, such as types of system interconnections and interactions with the main grid. The hybrid systems existent in the LSF, as well as the infrastructure for their interconnection are described. Subsequently, the commissioning process and the operational tests with the interconnection of the hybrid systems with each other and with the main grid are performed. At the end, a capacity building course on micro-grids and hybrid systems using the existent infrastructure in the LSF is proposed.
3

Operational Performance Evaluation of Four Types of Exit Ramps on Florida's Freeways

Lu, Linjun 01 January 2011 (has links)
This research focuses primarily on the analysis of exit ramp performance related to safety and operations. The safety analysis focuses on the impacts of different exit ramp types for freeway diverge areas and different factors contributing to the crashes that occur on the exit ramp sections. The operational analysis is based mainly on simulations by TSIS-CORSIM. Different ramp effects and guidance for selecting optimal exit ramp type are concluded. Issues related to ramp sections and crossroad sections are also demonstrated. Minimum ramp length and minimum distance between ramp terminal and downstream or upstream intersections are calculated. The operational analysis was conducted to determine different ramp effects and to provide guidance for selecting optimal exit ramp type. Comparisons of the operational performance of different types of exit ramps are made to present a method for choosing the optimal one. Some methods of evaluation (MOEs) are used to approach this objective, such as number of lane changes, average speed, delay time, etc. Data collection at 24 sites in Florida was conducted, and traffic simulations by TSIS-CORSIM were applied for analysis. Mathematical models were built to evaluate different impacts of these ramps based on simulations. All impact analysis is concluded to summarize a model for optimal exit ramp selection. In addition to ramp type evaluation and selection, issues related to ramp section and crossroad section are demonstrated. Minimum ramp length and minimum distance between ramp terminal and downstream or upstream intersections are calculated.
4

Implementação de infraestrutura laboratorial para análise operacional e capacitação em sistemas híbridos para geração de eletricidade / Implementation of Laboratory Infrastructure for Operational Analysis and Capacity Building in Hybrid Systems for Electricity Generation,

Kauê José Felipe Novaes Candido de Souza 24 May 2018 (has links)
Este trabalho apresenta o processo de ampliação da infraestrutura laboratorial de minirredes e sistemas híbridos do Laboratório de Sistemas Fotovoltaicos do Instituto de Energia e Ambiente da Universidade de São Paulo, (LSF-IEE/USP). O trabalho também contempla uma revisão do estado da arte de sistemas híbridos e minirredes, apresentando principalmente os aspectos técnicos, como formas de acoplamento, e interações com a rede elétrica de distribuição. Descrevem-se os sistemas híbridos presentes no LSF e a infraestrutura para sua interconexão. Posteriormente são realizados os processos de comissionamento e testes operacionais da interconexão dos sistemas híbridos entre si e com a rede elétrica. Ao final é proposto um curso de aperfeiçoamento em minirredes e sistemas híbridos utilizando a infraestrutura presente no LSF. / This work presents the expansion of the micro-grid and hybrid systems infrastructure at the Laboratory of Photovoltaic Systems of the Institute of Energy and Environment at the University of São Paulo (LSF-IEE / USP). The work also presents a review of the state of the art of hybrid systems and micro-grid, presenting mainly the technical aspects, such as types of system interconnections and interactions with the main grid. The hybrid systems existent in the LSF, as well as the infrastructure for their interconnection are described. Subsequently, the commissioning process and the operational tests with the interconnection of the hybrid systems with each other and with the main grid are performed. At the end, a capacity building course on micro-grids and hybrid systems using the existent infrastructure in the LSF is proposed.
5

Densidade de estradas em povoamentos de Pinus taeda l. em regime de desbastes e corte raso / Roads density in Pinus taeda L. stands in thinnings and clear cutting

Souza, Franciny Lieny 06 December 2016 (has links)
Submitted by Claudia Rocha (claudia.rocha@udesc.br) on 2017-12-12T13:30:05Z No. of bitstreams: 1 PGEF16MA073.pdf: 1558252 bytes, checksum: 078f732c32622d0875732cff37fb28d7 (MD5) / Made available in DSpace on 2017-12-12T13:30:05Z (GMT). No. of bitstreams: 1 PGEF16MA073.pdf: 1558252 bytes, checksum: 078f732c32622d0875732cff37fb28d7 (MD5) Previous issue date: 2016-12-06 / The objective of the present research was to analyze timber extraction operations and determining economically optimal density of forest roads in thinnings and clear cut for Pinus stands managed for multiple use, subsidizing the operations planning for forest sustainability. The survey was conducted in areas of harvest of Pinus taeda L., belonging to Florestal Gateados Ltda, in Campo Belo do Sul, SC. The study was divided into two stages. In the first, a technical analysis, modeling and cost productivity of logging activities in different situations and machines: (a) first thinning in cut to lenght system (CTL) with forwarder; (b) third roughing in CTL system with forwarder; (c) clear cut in with forwarder CTL system; and (d) clear cut in full tree system (FT) with skidder. Technical analysis was performed by means of a time and motion study, with a sampling error of less than 10%, being evaluated the elements of the operating cycle and given nominal productivity (Pn) and effective (Pe). The cost analysis was accomplished through the determination of production and operational costs for the accounting method. The operations were evaluated in different conditions of slope, direction of operation, distance of extraction, presence of rocky outcrop and volume by class tora, which were also regarded as independes variables to fit mathematical models for multiple regression for estimation of productivity, using the Stepwise Procedure. The main results were: for the first trim the Pn was 10,90 m3/h and total operating cost (COT) of R$/he. 181,12 For the third roughing the NP was 16,45 m3/h and COT of 185,58 R$/he. In clear cut, for forwarder if a Pn of 29,05 m3/h and COT of 244,58/he R$, while for the skidder obtained a Pn of 128,60 m3/h and COT of 218,31 R$/he. For the modeling of productivity of machines, the distance and the volume by tora were used as explanatory variables, being present in the estimates for the forwarder, in addition to the volume per cycle, in third, and slope in the first thinning and clear-cutting. For the skidder, the variables used were the distance and volume per cycle. In step two was given the economically optimum density (DOE) and acceptable (DAE) for different situations. The DOE was calculated by the indirect method, which is the product of the sum of the costs of reconstruction, maintenance, extraction and waste of productive area. First trim the current road density (of) was 45,28 m/ha, the DOE of 20,18 m/ha and the DAE of 28,26 m/ha. Third roughing the of was 95,08 m/ha, the DOE of 16,60 m/ha and the DAE of 21,68. In clear-cutting the of was 92,02 w/ha, being the DOE for the CTL system of 15,63 m/ha and DAE of 24,75 m/ha, while in the FT system DOE was 22,85 m/ha and 27,00 m DAE/ha. In General, the density of current roads was above the good and acceptable and should be carried out a redesign of operations targeting a road network within the acceptable density, resulting in lower costs and increased revenue to the company / O objetivo da presente pesquisa foi analisar operações de extração de madeira e determinar economicamente a densidade ótima de estradas florestais em desbastes e corte raso para povoamentos de Pinus manejados para uso múltiplo, subsidiando o planejamento das operações com vistas à sustentabilidade florestal. A pesquisa foi realizada em áreas de colheita de Pinus taeda L., pertencentes à empresa Florestal Gateados Ltda, em Campo Belo do Sul, SC. O estudo foi dividido em duas etapas. Na primeira, foi realizada uma análise técnica, de custos e modelagem da produtividade das atividades de extração de madeira em diferentes situações e máquinas: (a) primeiro desbaste em sistema de toras curtas (CTL) com forwarder; (b) terceiro desbaste em sistema CTL com forwarder; (c) corte raso em sistema CTL com forwarder; e (d) corte raso em sistema de árvores inteiras (FT) com skidder. A análise técnica foi realizada por meio de um estudo de tempos e movimentos, com um erro amostral menor que 10%, sendo avaliados os elementos do ciclo operacional e determinada a produtividade nominal (Pn) e efetiva (Pe). A análise de custos foi realizada através da determinação dos custos operacionais e de produção pelo método contábil. As operações foram avaliadas em diferentes condições de declividade, sentido de operação, distância de extração, presença de afloramento rochoso e classe de volume por tora, os quais também foram considerados como variáveis independes com intuito de se ajustar modelos matemáticos por regressão múltipla para a estimativa da produtividade, utilizando o procedimento Stepwise. Os principais resultados foram: para o primeiro desbaste a Pn foi de 10,90 m3/h e custo operacional total (COT) de 181,12 R$/he. Para o terceiro desbaste a Pn foi de 16,45 m3/h e COT de 185,58 R$/he. Em corte raso, para forwarder se obteve uma Pn de 29,05 m3/h e COT de 244,58 R$/he, enquanto que para o skidder se obteve uma Pn de 128,60 m3/h e COT de 218,31 R$/he. Para a modelagem da produtividade das máquinas, a distância e o volume por tora foram usadas como variáveis explicativas, estando presentes nas estimativas para o forwarder, além do volume por ciclo, em terceiro desbaste, e da declividade em primeiro desbaste e corte raso. Para o skidder, as variáveis utilizadas foram a distância e o volume por ciclo. Na etapa dois foi determinada a densidade economicamente ótima (DOE) e aceitável (DAE) para as diferentes situações de colheita. A DOE foi calculada pelo método indireto, sendo esta o produto do somatório dos custos de reconstrução, manutenção, extração e perda de área produtiva. Em primeiro desbaste a densidade de estradas atual (DE) foi de 45,28 m/ha, a DOE de 20,18 m/ha e a DAE de 28,26 m/ha. Em terceiro desbaste a DE foi de 95,08 m/ha, a DOE de 16,60 m/ha e a DAE de 21,68. Em corte raso a DE foi de 92,02 m/ha, sendo a DOE para o sistema CTL de 15,63 m/ha e DAE de 24,75 m/ha, enquanto que em sistema FT a DOE foi de 22,85 m/ha e DAE de 27,00 m/ha. De forma geral, a densidade de estradas atual foi acima da ótima e da aceitável, devendo ser realizado um replanejamento das operações visando uma malha viária dentro da densidade aceitável, resultando em menores custos e maiores receitas à empresa
6

Uplatnění metod operační analýzy při optimalizaci dopravy / Exercise of operational analysis methods in transport optimalization

KUČEROVÁ, Lucie January 2008 (has links)
In my dissertation I use mathematical simulation of the transport situation for proposal the optimal routing between suppliers and customers. Target of my work is to propose optimal wagon stock.
7

Analysis of transformations to socio-technical systems using agent based modeling and simulation

Shah, Anuj P. 24 February 2006 (has links)
Transformations to socio-technical systems may be enacted at fairly low levels, i.e., through changes in technology, processes, information and workers, to obtain a change in system level performance. This thesis provides a conceptual framework and a simulation platform to a priori computationally analyze the impact of such transformations. This thesis builds on the principles of cognitive engineering to describe the components of the work environment, i.e., technology, processes and information, in work relevant ways and using a structure-preserving model, i.e., a model form that describes the models using the same attributes and structure as used by system designers. This thesis also builds on the principles of agent-based modeling to model workers and their interactions with the work environment. These models are specified through a conceptual framework that includes declarative models describing which components are included within the system and their interrelations, and object-oriented models of those complex, dynamic behaviors that cannot be adequately described declaratively. Declarative modeling enables easy composition and modification of component models and, by declaring all required components collectively, a system model. This thesis established an XML representation for the declarative models, and developed a mechanism that automatically assembles, from the individual components' specifications and interrelations, a network-level model of the entire system in XML, which can serve to analyze network dependencies between components. The combination of the declarative and object-oriented models also enables computational simulations to predict the system performance that will emerge from a network of components when placed in a given scenario. Thus, this thesis also developed an agent-based simulation platform to support analysis of emergent behavior. The theoretical contributions of this thesis include the conceptual framework as a broadly applicable and structure-preserving representation of the important aspects of socio-technical system behavior, and associated extensions to cognitive engineering descriptions of the work environment. These insights, combined with the simulation platform, also enable computational modeling, analysis and prediction of socio-technical system performance with a comprehensiveness and detail not possible before. The theoretical and practical utility of these developments is demonstrated through a case study in air traffic control.

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