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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.
111

Redução de lead time em ambiente de fabricação sob encomenda por meio da abordagem Quick Response Manufacturing (QRM)

Chinet, Fernanda Silva 25 February 2014 (has links)
Made available in DSpace on 2016-06-02T19:52:03Z (GMT). No. of bitstreams: 1 5876.pdf: 7013934 bytes, checksum: 4e3ff62ae5a65cf8026d92111fa732ee (MD5) Previous issue date: 2014-02-25 / In the latest decades, companies have faced important and increasing challenges set by globalization in product markets and production factors. This way, consumers become highly demanding and are always searching for new products, highly qualified, customized and quickly produced. Given these changes, the speed of delivery and therefore the efforts to reduce lead time emerges as one of the main objectives adopted by a company to compete in the market, since the strategies based in time aim to provide faster answers to its customers. In this context, the present paper aims to describe a proposal to reduce the lead time from the application of the concepts and methodology tools Quick Response Manufacturing (QRM) in a capital good sector s company. In order to achieve the proposed objective, a literature review about the QRM methodology and POLCA system and a case study in a company that develops and manufactures machinery and custom made equipment. Thus, it was analyzed the main causes of the waiting in the manufacturing of pressure vessels process, and through improvement proposals, it was achieved the results and gains expected. The main results, other than the 40% reduction in lead time, are related to quality improvement, increase of process responsibility in the manufacturing and simplifying the production control. / Nas últimas décadas as empresas têm enfrentado importantes e crescentes desafios impostos pela globalização dos mercados de produtos e fatores de produção. Dessa forma, os consumidores tornam-se cada vez mais exigentes e estão sempre em busca de novos produtos, altamente qualificados, customizados e produzidos rapidamente. Diante destas transformações, a velocidade de entrega e, por conseguinte, a busca pela redução do lead time surge como um dos principais objetivos adotados por uma empresa para competir no mercado, visto que estratégias baseadas no tempo visam fornecer respostas rápidas a seus clientes. Neste contexto, o presente trabalho tem como objetivo geral apresentar uma proposta para a redução de lead time a partir da aplicação dos conceitos e ferramentas da metodologia Quick Response Manufacturing (QRM) em uma empresa do setor de bens de capital. A fim de atingir o objetivo proposto, foi realizada uma revisão da literatura sobre a metodologia QRM e sistema POLCA e um estudo de caso em uma empresa que desenvolve e fabrica máquinas e equipamentos sob encomenda. Dessa maneira, analisaram-se as principais causas de espera no processo de fabricação de vasos de pressão e, por meio de propostas de melhorias, chegou-se aos resultados e ganhos esperados. Os resultados principais, além da redução de 40% do lead time, estão relacionados à melhoria de qualidade, aumento de responsabilidade no processo de fabricação e simplificação do controle de produção.
112

Procedimentos como recursos para ação : um estudo sobre como o Cockpit de uma aeronave comercial gerencia situações anormais e de emergência

Carim Júnior, Guido Cesar January 2016 (has links)
Na aviação, os procedimentos para situações anormais e de emergência, geralmente organizados em checklists compilados no Quick Reference Handbook (QRH), são elaborados e revisados como mecanismos de controle organizacional. Esta abordagem, no entanto, tem mostrado limitações em servir como solução para todos os tipos de situações, principalmente para problemas não estruturados. Neste cenário, o conceito ‘procedimentos como recursos para a ação’ tem sido visto como uma abordagem alternativa, embora tenha sido desenvolvida apenas de forma incipiente. Assim, o objetivo geral desta tese foi propor um protocolo para revisão dos procedimentos disponíveis em cockpits de aviões comerciais como apoio aos pilotos durante a gestão de anomalia. Para atingir o objetivo, a pesquisa adotou a Design Science Research e foi dividida em quatro etapas: compressão do problema, sugestão e desenvolvimento, avaliação e conclusão. Um estudo etnográfico cognitivo conduzido em uma companhia aérea brasileira propiciou melhor entendimento do problema por meio de observações participantes, entrevistas retrospectivas, entrevistas em grupo, dados secundários e documentos técnicos. Os resultados mostraram como fatores contextuais fora do escopo do QRH geraram demandas extras e requereram estratégias de adaptação dos sistemas cognitivos correlacionados. Fragmentos do QRH e de recursos adicionais foram intercalados para apoiar essas estratégias. As sugestões de melhorias envolveram a reorganização do QRH, dos checklists e dos recursos adicionais, a fim de melhor apoiar o reconhecimento de anomalias, o diagnóstico de problemas e o curso de ação. As sete etapas do protocolo foram desenvolvidas com base nos princípios teóricos e empíricos derivados do estudo e, em seguida, o protocolo foi avaliado de acordo com cinco critérios. Enquanto o artefato teve um bom desempenho em dois critérios, três deles revelaram a necessidade de ajustes, que podem ser superados com novas aplicações em diferentes contextos. Em conclusão, o estudo atingiu os objetivos geral e específicos, contribuiu para a classe de problemas ao operacionalizar o conceito ‘procedimentos como recursos para a ação’ e contribuiu para solucionar o problema prático ao proporcionar um artefato para ajudar as companhias aéreas a revisar seus procedimentos e outros recursos de modo a melhor apoiar os pilotos na gestão de anomalias. / In aviation, procedures for abnormal and emergency situations, generally organized in checklists compiled in the Quick Reference Handbook (QRH), are designed and redesigned as mechanisms of organizational control. This approach, however, has shown some drawbacks as a solution for any situation, specially for unstructured problems. In this scenario, the concept ‘procedures and resources for action’ has been seen as an alternative approach, although it has been incipiently developed. Thus, the general objective of this thesis was to propose a protocol for redesigning the procedures available in commercial aircraft cockpits as means of supporting pilots during anomaly management. To achieve the objective, the research adopted the Design Science Research approach and was divided into four stages: awareness of the problem, suggestion and development, evaluation and conclusion. A cognitive ethnographic study conducted in a Brazilian airline provided better understanding of the problem through participant observations, retrospective interviews, group interviews, secondary data and technical documents as sources of data. The results showed how contextual factors beyond the QRH scope generated extra demands and required adaptive strategies from the joint cognitive systems. Fragments from the QRH and from additional resources were interleaved to support these strategies. The design implications involved the reorganization of the QRH, the checklist and the additional resources in order to better support the anomaly recognition, the problem diagnosis and the course of action. The seven steps of the protocol were developed based on the theoretical and empirical principles derived from the study and, then, the protocol was evaluated according to five criteria. While the artefact performed well in two criteria, in three of them revealed opportunities of improvement, which can be overcame with more applications in different settings. In conclusion, the study achieved general and specifics objectives, contributed to the class of problems by operationalizing the concept ‘procedures as resources for action’ and contributed to solve the practical problem by providing an artefact that help airlines to redesign procedures and other resources in order to better support pilots during anomaly management.
113

Framtagning av snabbkoppling i polymera material för vätskekylda datacentraler / Development of a quick connection coupling in polymeric material for liquid cooled data centres

Karlsson, Louise, Sjöberg, Alexander January 2018 (has links)
Examensarbetets mål är att ta fram ett konceptförslag på en snabbkoppling på uppdrag av CEJN. Rapporten redovisar de metoder som använts för att nå slutligt resultat. Utvecklad snabbkoppling syftar till en marknad för vätskekylning i datacenter. CEJN önskar ligga i framkant på den expansiva marknaden, vilket kräver att tillverkningskostnaderna för befintlig aluminiumkoppling reduceras, bland annat genom materialbyte till plast. Företaget har idag ingen plasttillverkning i huset. Genereringsarbetet baseras på förstudie i form av litteraturstudier, konkurrensanalyser delvis genom demontering av befintliga produkter på marknaden, samt användartester. Prototyper har använts för test och utvärdering i flera stadier i processen. Snabbkopplingens yttre komponenter, som även visades vara de största kostnadsbärarna, utvecklades som separata delproblem så som låsmekanism, utformning av inre o-ringsspår och sammanfogning för att tillåta montering och säkerställa spillsäkerhet. Beslutsunderlag för slutliga konceptval baserades på kostnader, användande utifrån tillverkade prototyper samt utlåtanden från externa experter inom plasttillverkning, varpå konceptval kunde utföras tillsammans med uppdragsgivande företag. Dellösningarna anpassades i ett slutligt koncept som reducerar kostnader och samtidigt uppfyller krav gällande prestanda, utseende och användbarhet. Projektet med slutligt konceptförslag föreslås ligga till grund för vidareutveckling och tester för att säkerställa den högkvalitativa produkt CEJN eftersträvar. / The objective of the Bachelor thesis is to create a concept proposal in collaboration with CEJN. This report is presenting activities involved in the development process used to obtain the final result. Referring to the expansive market for liquid cooled data centres, CEJN aims to be in the leading edge with a new quick connection coupling. This demands reduction of production costs relative their existing aluminium coupling, partly by change of material to plastics. Outsourcing is relevant as the company does not produce plastic components at set. The idea generation phase has been based on a pre-study consisting of literature studies, analyses of competing products through demolition, and user tests. Prototypes have been used for testing and evaluation throughout the process. The outer components of the quick connection coupling proved to be among the costliest details. Locking mechanism, the formation of an inner slot for seals and the junction between nipple- or coupling body and back part to allow assembly and to ensure a non-drip application, have been developed separately. Decisions for final concept selection were made with the company of commission, with data regarding costs, usage interpreted from prototypes and verdicts from external experts within plastics production. Sub solutions mentioned, were combined into a final concept which reduces costs and fulfils demands regarding performance, appearance and usability. The material from the project is propositioned to form the basis for further development and testing to ensure high product quality representing CEJN.
114

Étude et modélisation de la polymérisation dynamique de composites à matrice thermodurcissable / Analysis and modeling of the dynamic polymerization of thermosetting matrix composites

Paris, Christophe 28 November 2011 (has links)
La cuisson rapide de préimprégnés est une problématique d'actualité qui sous entend les nécessités de rentabilité dans l'industrie aéronautique. Cette étape est basée sur la maîtrise du degré d'avancement de réaction du système thermodurcissable au cours du cycle qui régit l'ensemble des propriétés finales des pièces composites. La caractérisation et la modélisation cinétique du préimprégné aéronautique M21/T700 sont réalisées en vue d'appliquer des dynamiques de mise en oeuvre rapides applicables sur une installation de thermocompression dotée d'un moule chaué par induction de technologie Cage System de Roctool. La construction de diagrammes Temps Température Transformation et la réalisation d'un couplage thermo-cinétique par éléments finis permettent de proposer des cycles optimisés d'une durée de moins de 2 heures (au lieu de 4h30 en cuisson autoclave), en préservant la présence de particules de thermoplastiques dans la matrice. L'étude des propriétés des plaques fabriquées montre des résultats comparables à ceux obtenus pour des pièces mises en oeuvre lors de cycles standards de fabrication à l'aide du procédé autoclave. / The increase of composite content in aerospace structures requires an improvement of profitability through high curing processes. The curing step is based on the control of the degree of cure of the thermosetting system that governs the final properties of the composite parts. The Cage System technology from the Roctool company enables high curing rates thanks to induction heating system. Thus, the characterization and the kinetic modeling of the M21/T700 aeronautical prepreg have been realized for such sollicitations (i.e. high heating rates). To provide a better temperature control, the thermal and kinetic interactions are also considered by finite element modeling of composite thickness. Time Temperature Tranformation diagrams have been set up to build short curing cycle of less than 2h (instead of 4h30 in autoclave curing), considering the presence of thermoplastic particules. Finally, the part properties are in good agreement with the autoclave cycle recommended by the material supplier.
115

Kartläggning av kvicklera med hjälp av flygresistivitetsmätningar / Mapping quick clay using airborne resistivity measurements

Jönsson, Clara, Larsson, Linn January 2017 (has links)
Purpose: One of the major soil problems that the construction industry may face is the presence of a certain type of highly sensitive marine clay, known as quick clay. The quick clay possesses properties that allow the clay to move from being relatively stable to on mechanical impact losing virtually all shear strength and act as a viscous mass. The majority of the Swedish, Norwegian and Canadian landslides, caused by quick clay, have caused significant consequences due to lack of bearing capacity of quick clay. In order to prevent these landslides knowledge about where there is quick clay is required. A large-scale mapping work has therefore been ongoing for a long time. The government has for some time been researching how to streamline mapping work and the result has shown a connection between quick clay attendance and increased resistivity. The purpose of this study is to develop a theoretical framework for areas with higher risk for presence of quick clay based on linking the resistivity to geotechnical properties. Method: The study has mainly applied quantitative data collection methods in the form of data analyzes combined with literature studies. Measurement data used in the study comprise of data collected through geotechnical and geophysical surveys. Literature studies have mainly been supported by reports from previous research in the field. Result: The result of the study points to a variety of geological factors that can give rise to increased risk of quick clay existence such as good permeability, artesian groundwater and uneven mountain subsidence etc. The study also shows a possible link between resistivity and sensitivity. Consequences: The study demonstrates the possibility of linking resistivity to the geotechnical property sensitivity to facilitate and streamline the mapping of quick clay through airborne resistivity measuring. Limitations: The study is limited to studying two research areas in south western Sweden, Strömstad and Lödöse. The study intends to examine the evidence from previous surveys and no further supplementary studies are conducted. The work is also delimited to study the geotechnical and geophysical properties of quick clay (in terms of resistivity). Chemical aspects are not taken into account. / Syfte: Ett av de större markproblem bygg- och anläggningsbranschen kan tvingas stå inför är förekomsten av en viss typ av högsensitiv havsavsatt lera, kallad kvicklera. Kvickleran besitter egenskaper som innebär att leran kan gå från relativt stabil till att vid mekanisk påverkan förlora praktiskt taget all sin skjuvhållfasthet och uppträder som en trögflytande massa. Majoriteten av de svenska, norska och kanadensiska lerskred som medfört betydande konsekvenser har varit ett resultat av kvicklerans bristande bärighet. För att förebygga dessa kvickleraskred krävs vetskap om var kvicklera förekommer. Ett omfattande kartläggningsarbete har därför pågått under en lång tid. Staten har under en tid bedrivit forskning för att effektivisera kartläggningsarbetet och resultatet har visat på ett samband mellan kvickleraförekomst och förhöjd resistivitet. Syftet med detta examensarbete är att ta fram ett teoretiskt ramverk för områden med större risk för förekomst av kvicklera baserat på att koppla samband mellan resistivitet och geotekniska egenskaper i form av vattenkvot, sensitivitet och densitet. Metod: I studien har i huvudsak kvantitativa datainsamlingsmetoder i form av dataanalyser tillämpats i kombination med litteraturstudier. Mätdatat som studien omfattar är insamlad via geotekniska och geofysiska undersökningar, litteraturstudierna har främst tagit stöd i rapporter från tidigare forskning inom området. Resultat: Resultatet pekar på en rad olika geologiska faktorer som kan ge upphov till ökad risk för kvickleraförekomst, exempelvis god permeabilitet, artesiskt grundvatten samt ojämn bergunderyta etc. Studien visar även på en möjlig koppling mellan resistivitet och sensitivitet. Konsekvenser: Studien visar på möjligheten att koppla resistivitet till den geotekniska egenskapen sensitivitet för att underlätta och effektivisera kartläggningen av kvicklera genom flygburna resistivitetsmätningar. Begränsningar: Uppsatsen begränsas till att studera två undersökningsområden i sydvästra Sverige, Strömstad och Lödöse. Studien avser granska underlag från tidigare utförda undersökningar och inga ytterligare kompletterande undersökningar har utförts. Arbetet avgränsas till att studera kvicklerans geotekniska egenskaper samt dess resistivitetsegenskaper. Arbetet tar således inte hänsyn till kemiska aspekter.
116

Kommunikationen mellan produktutvecklande modeleverantörer och deras producenter

Wallgren, Esther, Johansson, Lisa, Andersson, Sofia January 2017 (has links)
Kommunikationen mellan en produktutvecklande modeleverantör och deras producenter är en pågående process. Kommunikation i allmänhet binder samman människor genom tal och skrift, men kan också vara en bidragande faktor till oenighet. Kommunikation i alla dess former används dagligen och är ett viktigt verktyg som måste fungera korrekt. Om brister i kommunikationen uppstår kan diskussioner väckas till liv och inom modeindustrin kan samarbeten ställas in och kontrakt annulleras. Kommunikationen mellan den produktutvecklande modeleverantören och deras producenter kan bli missförstådd och inte tolkad utifrån det uppsåt företagen planerat. Det kan leda till problem med ledtider, försäljningssiffror och försenade leveranser. Syftet med studien är att analysera varför eventuella problem sker i kommunikationen mellan svenska produktutvecklande modeleverantörer och deras producenter i utlandet. Följande kandidatuppsats är uppdelad i kapitel 1 – 6 och kommer besvara syftet genom att granska kommunikationen mellan de två parterna, vilka kommunikationssvårigheter som finns samt vilka parametrar som är viktiga för att kommunikationen ska fungera. Den primära teorin utgörs av det empiriska resultatet som består av intervjuer med nio svenska produktutvecklande modeleverantörer. Personliga intervjuer valdes för att tillgå så stor andel information som möjligt rörande ämnet. Dessutom har observationer av den Textila Värdekedjan, Supply Chain Management, Sustainable Supply Chain Management, Total Quality Management, Quick Response, Fast Fashion samt Organisationskultur genomförts. Även andra viktiga strategier och aspekter som handlar om kommunikation har analyserats. Studien visar att brister i kommunikationen uppstår dagligen för svenska produktutvecklande modeleverantörer. Kommunikationssvårigheter uppkommer av bland annat språkbarriärer och kulturella skillnader. Konsekvenser av misstag i kommunikationen kan vara förödande och ha stor påverkan på relationen mellan de svenska produktutvecklande modeleverantörerna och deras producenter. Följaktligen presenteras studiens slutsats samt förslag på vidare forskning. Slutligen redovisas använda källor och bilagor.
117

A Detailed Proof of the Prime Number Theorem for Arithmetic Progressions

Vlasic, Andrew 05 1900 (has links)
We follow a research paper that J. Elstrodt published in 1998 to prove the Prime Number Theorem for arithmetic progressions. We will review basic results from Dirichlet characters and L-functions. Furthermore, we establish a weak version of the Wiener-Ikehara Tauberian Theorem, which is an essential tool for the proof of our main result.
118

Návrh a vývoj napájecího zdroje notebooků do běžných motorových vozidel / A Design and Development of a Power Supply for Laptops in Ordinary Motor Vehicles

Urban, Michal January 2021 (has links)
Cílem této práce je navrhnout a sestavit napájecí zdroj pro notebooky různých výrobců pro použití v osobních a nákladních automobilech a na motocyklech s výstupním výkonem až 120W. Výsledný zdroj obsahuje USB-C konektor pro podporu napájení notebooků a chytrých zařízení s podporou Power Delivery, dále USB-A konektor s podporou Quick Charge 3.0 a také 12V automobilovou zásuvku pro možnost připojení dalšího automobilového příslušenství. Napájecí zdroj dále disponuje ochranou proti přepětí a přepólování vstupního napětí a také ochranou proti přetížení jednotlivých výstupů. Součástí zařízení je také LED displej, který uživateli umožňuje pomocí vstupního rozhraní jednoduše nastavit výstupní napětí pro notebook a sledovat aktuální hodnoty všech výstupů. Pro nastavování výstupu, indikaci a ochrany je použit mikrokontroler Arduino Nano.
119

Analýza vybrané firmy / Analysis of the Selected Firm

Piskatá, Sylva January 2010 (has links)
This master's thesis focuses on the company analysis that is doing a business in the field of agriculture particularly in viniculture. The preamble theoretical part is dedicated to the basic theses of selected analytical methods, which are the SWOT analysis, SLEPTE analysis, Porter's analysis, Fundamentals analysis and Quick test. These methods are applied in the practical part. The last part contains the recommendation to improve the present situation of the company.
120

Finanční analýza vybrané firmy / Financial Analysis of the Selected Firm

Dobešová, Věra January 2011 (has links)
Tato diplomová práce pojednává o finančním hodnocení společnosti XYZ plc., které je založeno na použití vybraných metod finanční analýzy za období 2008 až 2010. The hlavní cíl této práce je navrhnout opatření vedoucí ke zlepšení finanční situace společnosti v nadcházejících letech

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