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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.
11

Equilibrium states and their local product structure for partially hyperbolic diffeomorphisms. / Estados de equilíbrio e sua estrutura de produto local para difeomorfismos parcialmente hiperbólicos.

Jorge Luis Crisostomo Parejas 26 September 2016 (has links)
We address the problem of existence and uniqueness (or finiteness) of ergodic equilibrium states for a natural class of partially hyperbolic diffeomorphisms homotopic to Anosov. We propose to study the disintegration of equilibrium states along the central foliation as a tool to develop the theory of equilibrium states for partially hyperbolic dynamics. For a large class of low variational potentials we obtain existence and uniqueness of the equilibrium state and we also obtain a dichotomy between finiteness of ergodic equilibrium states and hyperbolicity of such measures. We also prove that the measure of maximal entropy for accessible partially hyperbolic diffeomorphisms of 3-manifold having compact center leaves can be written locally as the product of three measures defined on the local stable, central and unstable foliations provided that such measure is unique. We verify that the local product structure does not hold when the number of measures of maximal entropy is larger than one. / Abordamos o problema de existência e unicidade (ou finitude) dos estados de equilíbrio ergódicos para uma classe natural de difeomorfismos parcialmente hiperbólicos homotópicos a um Anosov. Propomos estudar a desintegração dos estados de equilíbrio ao longo da folheação central como uma ferramenta para desenvolver a teoria de estados de equilíbrio para sistemas parcialmente hiperbólicos. Para uma classe de potenciais com variação pequena obtemos existência e unicidade de estados de equilíbrio e também obtemos uma dicotomia entre finitude dos estados de equilíbrio ergódicos e hiperbolicidade de tais medidas. Obtemos também que as medidas de máxima entropia para difeomorfismos parcialmente hiperbólicos acessíveis definidos numa 3-variedade tendo folhas centrais compactas podem ser escritas localmente como o produto de três medidas definidas nas folheações stável, central e instável locais sempre que tal medida é única. Verificamos que a estrutura de produto local não é valida quando o número de medidas de máxima entropia é maior que um.
12

Equilibrium states and their local product structure for partially hyperbolic diffeomorphisms. / Estados de equilíbrio e sua estrutura de produto local para difeomorfismos parcialmente hiperbólicos.

Parejas, Jorge Luis Crisostomo 26 September 2016 (has links)
We address the problem of existence and uniqueness (or finiteness) of ergodic equilibrium states for a natural class of partially hyperbolic diffeomorphisms homotopic to Anosov. We propose to study the disintegration of equilibrium states along the central foliation as a tool to develop the theory of equilibrium states for partially hyperbolic dynamics. For a large class of low variational potentials we obtain existence and uniqueness of the equilibrium state and we also obtain a dichotomy between finiteness of ergodic equilibrium states and hyperbolicity of such measures. We also prove that the measure of maximal entropy for accessible partially hyperbolic diffeomorphisms of 3-manifold having compact center leaves can be written locally as the product of three measures defined on the local stable, central and unstable foliations provided that such measure is unique. We verify that the local product structure does not hold when the number of measures of maximal entropy is larger than one. / Abordamos o problema de existência e unicidade (ou finitude) dos estados de equilíbrio ergódicos para uma classe natural de difeomorfismos parcialmente hiperbólicos homotópicos a um Anosov. Propomos estudar a desintegração dos estados de equilíbrio ao longo da folheação central como uma ferramenta para desenvolver a teoria de estados de equilíbrio para sistemas parcialmente hiperbólicos. Para uma classe de potenciais com variação pequena obtemos existência e unicidade de estados de equilíbrio e também obtemos uma dicotomia entre finitude dos estados de equilíbrio ergódicos e hiperbolicidade de tais medidas. Obtemos também que as medidas de máxima entropia para difeomorfismos parcialmente hiperbólicos acessíveis definidos numa 3-variedade tendo folhas centrais compactas podem ser escritas localmente como o produto de três medidas definidas nas folheações stável, central e instável locais sempre que tal medida é única. Verificamos que a estrutura de produto local não é valida quando o número de medidas de máxima entropia é maior que um.
13

Enhancing understanding of company-wide product data management in ICT companies

Kropsu-Vehkaperä, H. (Hanna) 24 April 2012 (has links)
Abstract Data is becoming more critical success factor as business processes rely increasingly on information systems. Product data is required to produce, sell, deliver, and invoice a product in information systems. Traditionally, product data and product data management (PDM) studies have focused on product development and related activities, with less attention being paid to PDM in other lifecycle phases. The purpose of this doctoral dissertation is to clarify challenges and prerequisites for company-wide PDM. The study covers the entire product lifecycle and provides potential solutions for developing company-wide PDM and enhancing PDM understanding as a company-wide action. The study was realised by collecting and analysing data from those ICT companies that are seeking for better ways to manage a wide product-range, technologically complex products and comprehensive solutions by enhancing their data management practices. The empirical practitioner’s experiences and perceptions are seen to have increased the knowledge in company-wide PDM. This study adopted a case study approach and utilises interviews as the main data collection method. This study indicates that company managers have already realised that successful business operations require a higher-level understanding of products and related product data. In practice, however, several challenges hinder the ability to achieve the goal of higher-level business-driven PDM. These challenges include product harmonisation, PDM process development requirements and information systems development requirements. The results of this research indicate that product harmonisation is required to better support efficient product data management. Understanding the true nature of product data, that is combination of product master data and other general product data, and the content of product data from different stakeholder perspectives are prerequisites for functional company-wide PDM. Higher-level product decisions have a significant impact on product data management. Extensive product ranges require general guidelines in order to be manageable, especially as even single products are complex. The results of this study indicate that companies should follow a top-down approach when developing their PDM practices. The results also indicate that companies require a generic product structure in order to support unified product management. The main implication of this dissertation is the support it provides for managers in terms of developing true company-wide product data management practices. / Tiivistelmä Tiedosta on tullut tärkeä liiketoiminnan menestystekijä liiketoimintaprosessien hyödyntäessä yhä vahvemmin tietojärjestelmiä. Tuotteisiin liittyvä tieto on olennaista, jotta tuote voidaan valmistaa, myydä, toimittaa ja laskuttaa. Tuotetietoa ja sen hallintaa on perinteisesti tarkastelu tuotekehityslähtöisesti kun tämä tutkimus pyrkii ymmärtämään tuotetiedon hallintaa kattaen myös edellä mainitut yrityksen toiminnot. Tämän tutkimuksen tavoitteena on tunnistaa haasteita ja perusedellytyksiä yrityksenlaajuisten tuotetiedonhallinnan käytäntöjen kehittämiseksi. Tuotetiedon hallinta yrityksen laajuisena toimintona vaatii ymmärrystä eri toimijoista, jotka käyttävät tuotetietoa; tiedon luonteesta sekä tiedon hyödyntämisestä eri prosesseissa. Tutkimus toteutettiin ICT yrityksissä, joissa tuotetiedon käytäntöjä tehostamalla haetaan keinoja hallita laajaa tuotteistoa, teknologisesti monimutkaisten tuotteita sekä kokonaisratkaisuja. Käytännön toimijoiden kokemukset ja käsitykset ovat ensiarvoisen tärkeitä lisätessä tietoa yrityksen laajuisesta tuotetiedonhallinnasta. Tutkimus toteutettiin tapaustutkimuksen menetelmin, joissa pääasiallisena tiedonkeruu menetelmänä hyödynnettiin haastatteluja. Tämä tutkimus osoittaa, että liiketoimintalähtöisen tuotetiedon hallinan kehittäminen on ajankohtaista yrityksissä. Tutkimuksessa tunnistetaan lukuisia haasteita, jotka ovat estäneet liiketoimintalähtöisen tuotetiedonhallinnan saavuttamisen. Näitä haasteita ovat: tuotteen harmonisointi yrityksen eri toiminnoissa, tuotetiedon hallinnan prosessien kehittämisen vaatimukset sekä tietojärjestelmien kehittämisen vaatimukset. Tutkimustulosten mukaan tuotteiston harmonisointi on yksi perusedellityksistä tehokkaalle tuotetiedon hallinnalle. Yrityksen kattava tuotetiedoen hallinta vaatii myös tuotetiedon todellisen luonteen ymmärtämistä, joka koostuu tuotteen master datasta sekä muusta tuotetiedosta. Lisäksi on olennaista ymmrättää tuotetiedon sisältö sen todellisten käyttäjien näkökulmasta käsin. Tämän tutkimuksen tulokset osoittavat myös, että tuotetiedon hallinnan kehittäminen pitäisi edetä ”top-down” eli ylhäältä-alas periaatteen mukaan. Tulokset myös viittaavat siihen, että geneerinen tuoterakenne tukee yhdenmukaisia tuotehallinta käytäntöjä. Nämä tulokset tarjoavat työssä esitettyjen kuvausten ja mallien ohella tukea tuotetiedon hallinnan käytäntöjen kehittämiseen yrityksen laajuisesti.
14

Avaliação de um ambiente computacional integrado para desenvolvimento de produtos no segmento de bens de capital com engenharia sob encomenda / Evaluation of an integrated computerized environment for engineered-to-order product development in capital goods segment

Pereira, Moacir Marques 18 November 2005 (has links)
Este trabalho avalia o grau em que a integração de sistemas de informação tem atendido ao desenvolvimento de bens de capital com engenharia sob encomenda, com base em objetivos de desempenho para o processo de desenvolvimento de produtos. Descreve uma investigação, realizada por meio de pesquisa-ação, sobre o ambiente de desenvolvimento de produtos em uma indústria de bens de capital, conduzida sob a perspectiva organizacional e da tecnologia da informação. Objetiva aumentar a difusão deste tipo de informação para os profissionais deste ramo de atividade e comunidade científica, bem como servir como base para pesquisas e ações de melhoria para a empresa estudada. Focaliza a relevância da caracterização de um modelo de referência para o processo de desenvolvimento de produtos que otimize as atividades de tomada de decisão, controle de fluxo de trabalho, armazenamento de informações e documentos e retro-alimentação de informações em ambientes com engenharia sob encomenda. Apresenta os desafios enfrentados pela empresa estudada quanto à estabilização dos seus processos após uma ampla reformulação da aplicação de sistemas de informação, abordando elementos de sua dinâmica organizacional e diagnosticando o comportamento destes elementos diante das integrações executadas. Aborda ainda os aspectos humanos envolvidos neste segmento, considerando-os como fatores críticos para a aplicação e desenvolvimento de soluções / This work evaluates the support level offered by integrated information systems to engineered-to-order development of capital goods, based on the product development process performance objectives. It describes an investigation, performed by means of an action-research, about the product development environment in a capital goods industry, carried out under the organizational and information technology perspectives. It aims to increase the diffusion of this kind of information among the professionals in this production segment and scientific community, as well to serve as a research and improvement actions base to the studied company. The work focuses on the relevance of a reference model characterization to the product development process in order to optimize the decision making activities, workflow control, document and information storage and feedback in engineering-to-order environments. It presents the challenges faced by the studied company to reach the processes stabilization after a broad changeover of its information systems applications, analyzing its dynamics organizational elements and making a diagnosis of these elements behaviour, considering the achieved integration. It still analyzes the human aspects involved in this industry segment, considering these aspects as critical factors for solutions development and application
15

Avaliação de um ambiente computacional integrado para desenvolvimento de produtos no segmento de bens de capital com engenharia sob encomenda / Evaluation of an integrated computerized environment for engineered-to-order product development in capital goods segment

Moacir Marques Pereira 18 November 2005 (has links)
Este trabalho avalia o grau em que a integração de sistemas de informação tem atendido ao desenvolvimento de bens de capital com engenharia sob encomenda, com base em objetivos de desempenho para o processo de desenvolvimento de produtos. Descreve uma investigação, realizada por meio de pesquisa-ação, sobre o ambiente de desenvolvimento de produtos em uma indústria de bens de capital, conduzida sob a perspectiva organizacional e da tecnologia da informação. Objetiva aumentar a difusão deste tipo de informação para os profissionais deste ramo de atividade e comunidade científica, bem como servir como base para pesquisas e ações de melhoria para a empresa estudada. Focaliza a relevância da caracterização de um modelo de referência para o processo de desenvolvimento de produtos que otimize as atividades de tomada de decisão, controle de fluxo de trabalho, armazenamento de informações e documentos e retro-alimentação de informações em ambientes com engenharia sob encomenda. Apresenta os desafios enfrentados pela empresa estudada quanto à estabilização dos seus processos após uma ampla reformulação da aplicação de sistemas de informação, abordando elementos de sua dinâmica organizacional e diagnosticando o comportamento destes elementos diante das integrações executadas. Aborda ainda os aspectos humanos envolvidos neste segmento, considerando-os como fatores críticos para a aplicação e desenvolvimento de soluções / This work evaluates the support level offered by integrated information systems to engineered-to-order development of capital goods, based on the product development process performance objectives. It describes an investigation, performed by means of an action-research, about the product development environment in a capital goods industry, carried out under the organizational and information technology perspectives. It aims to increase the diffusion of this kind of information among the professionals in this production segment and scientific community, as well to serve as a research and improvement actions base to the studied company. The work focuses on the relevance of a reference model characterization to the product development process in order to optimize the decision making activities, workflow control, document and information storage and feedback in engineering-to-order environments. It presents the challenges faced by the studied company to reach the processes stabilization after a broad changeover of its information systems applications, analyzing its dynamics organizational elements and making a diagnosis of these elements behaviour, considering the achieved integration. It still analyzes the human aspects involved in this industry segment, considering these aspects as critical factors for solutions development and application
16

Product portfolio management over horizontal and vertical portfolios

Tolonen, A. (Arto) 10 June 2016 (has links)
Abstract The main objective of this study is to clarify the current challenges and preconditions relating to product portfolio management (PPM) and widen the PPM framework over horizontal and vertical portfolios, including a related governance model, strategic performance management and the PPM process. This study analyses comprehensively the current PPM literature and the relevant practices of 10 case companies representing business areas such as hardware (HW), software (SW) and Services. This study approaches PPM from a more comprehensive viewpoint as all product life cycle phases and product structure levels are not covered well in this context by the earlier literature. The principal results of this study involve revealing the need for a new PPM governance model including strategic targets, KPIs and the PPM process according to vertical and horizontal portfolios. The created PPM framework clarifies the strategic role of PPM in cross-functional analysis and decision making for commercial and technical portfolios. The role and the impact of strategic PPM have been further enhanced by positioning the PPM process on the level of other business processes. The created PPM framework enhances the collaboration between business and engineering teams. The managerial implications include the potential preconditions of clarifying the dynamic and active role of PPM at the level of other business processes. The findings can aid business managers in understanding PPM as an entity that has a role in managing the entire product portfolio and its renewal based on strategic performance measures over horizontal and vertical portfolios according to cross-functional governance bodies. This highlights the criticality of managing all items both in commercial and technical portfolios. The role of other business processes should be highly operational by executing product development, marketing and sales, delivery and care activities according to PPM decisions. The primary role of PPM should be active management of the entire product portfolio over product life cycle phases and product structure levels, instead of merely focusing on new product development, to ensure product portfolio renewal. / Tiivistelmä Tämä tutkimus selventää tuoteportfolion hallintaan liittyviä edellytyksiä ja haasteita, sekä laajentaa tuoteportfolion hallintamallia, suorituskyvyn johtamista ja prosessia horisontaalisesti ja vertikaalisesti. Tuoteportfolion hallintaa on lähestytty kattavasti analysoimalla nykyistä kirjallisuutta, sekä kymmenen kohdeyrityksen käytänteitä nykytila-analyysin keinoin. Kohdeyritykset edustavat useita liiketoiminta- ja tuotealueita kattaen laitteiston, ohjelmiston ja palvelut. Tämä tutkimus lähestyy tuoteportfolion hallintaa laajemmalta katsantokannalta kuin nykyinen kirjallisuus joka ei kata kaikkia tuotteen elinkaaren vaiheita ja tuoterakennetasoja. Tämän väitöstutkimuksen tärkeimmät tulokset liittyvät uuden tuoteportfolion hallintamallin tarpeellisuuden esille tuomiseen, sisältäen tuoteportfolion strategiset tavoitteet, suorituskykymittarit ja hallintaprosessin perustuen vertikaalisiin ja horisontaalisiin tuoteportfolioihin. Luotu viitekehys selkeyttää tuoteportfolion hallinnan strategista roolia organisaatiorajat ja liiketoimintaprosessit ylittävässä analyysissa ja päätöksenteossa liittyen kaupallisiin ja teknisiin tuoteportfolioihin. Strategisen tuoteportfolion hallinnan roolia ja merkitystä on erityisesti korostettu nostamalla tuoteportfolion hallintaprosessi muiden liiketoimintaprosessien tasolle. Tässä tutkimuksessa luotu tuoteportfolion hallinnan viitekehys vahvistaa yhteistyötä liiketoiminnanjohto- ja insinööritiimien välillä kaikilla organisaatiotasoilla. Työn kontribuutiot yritysjohdolle korostavat tuoteportfolion hallintaprosessin keskitettyä, dynaamista ja aktiivista roolia johtaa yrityksen kaupallisia ja teknisiä nimikkeitä horisontaalisesti ja vertikaalisesti kokonaisuutena perustuen strategisiin suorituskykymittareihin. Tuoteportfolion hallinta yli horisontaalisten ja vertikaalisten portfolioiden mahdollistaa tuoteportfolion uudistumisen yli kaikkien elinkaarivaiheiden ja tuoterakennetasojen. Muiden liiketoimintaprosessien roolin tulisi olla selkeästi operatiivinen toteuttaen tuotekehitykseen, markkinointiin, myyntiin, tilaamiseen, hankintaan, toimittamiseen ja huoltoon liittyviä tehtäviä perustuen strategisiin tuoteportfolion hallinnan tavoitteisiin ja suorituskykymittareihin.
17

A plm implementation for aerospace systems engineering-conceptual rotorcraft design

Hart, Peter Bartholomew 08 April 2009 (has links)
The thesis will discuss the Systems Engineering phase of an original Conceptual Design Engineering Methodology for Aerospace Engineering-Vehicle Synthesis. This iterative phase is shown to benefit from digitization of Integrated Product&Process Design (IPPD) activities, through the application of Product Lifecycle Management (PLM) technologies. Requirements analysis through the use of Quality Function Deployment (QFD) and 7 MaP tools is explored as an illustration. A "Requirements Data Manager" (RDM) is used to show the ability to reduce the time and cost to design for both new and legacy/derivative designs. Here the COTS tool Teamcenter Systems Engineering (TCSE) is used as the RDM. The utility of the new methodology is explored through consideration of a legacy RFP based vehicle design proposal and associated aerospace engineering. The 2001 American Helicopter Society (AHS) 18th Student Design Competition RFP is considered as a starting point for the Systems Engineering phase. A Conceptual Design Engineering activity was conducted in 2000/2001 by Graduate students (including the author) in Rotorcraft Engineering at the Daniel Guggenheim School of Aerospace Engineering at the Georgia Institute of Technology, Atlanta GA. This resulted in the "Kingfisher" vehicle design, an advanced search and rescue rotorcraft capable of performing the "Perfect Storm" mission, from the movie of the same name. The associated requirements, architectures, and work breakdown structure data sets for the Kingfisher are used to relate the capabilities of the proposed Integrated Digital Environment (IDE). The IDE is discussed as a repository for legacy knowledge capture, management, and design template creation. A primary thesis theme is to promote the automation of the up-front conceptual definition of complex systems, specifically aerospace vehicles, while anticipating downstream preliminary and full spectrum lifecycle design activities. The thesis forms a basis for additional discussions of PLM tool integration across the engineering, manufacturing, MRO and EOL lifecycle phases to support business management processes.

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