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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.
691

Motives for Participation in Open-Source Software Projects: A Survey among R Package Authors

Mair, Patrick, Hofmann, Eva, Gruber, Kathrin, Hatzinger, Reinhold, Zeileis, Achim, Hornik, Kurt 04 1900 (has links) (PDF)
One of the cornerstones of the R system for statistical computing is the multitude of contributed packages making an extremely broad range of statistical techniques and other quantitative methods freely available. This study investigates which factors are the crucial determinants responsible for the participation of the package authors in the R project. For this purpose a survey was conducted among R package authors, collecting data on different types of participation in the R project, three psychometric scales (hybrid forms of motivation, work design characteristics, and values), as well as various specie-demographic factors. These data are analyzed using item response theory and generalized linear models, showing that the most important determinants for participation are a hybrid form of motivation and the knowledge characteristics of the work design. Other factors are found to have less impact or influence only specific aspects of participation. (authors' abstract) / Series: Research Report Series / Department of Statistics and Mathematics
692

Dynamic vehicle routing : solution methods and computational tools / Méthodes de résolution et outils informatiques pour les tournées de véhicules dynamiques

Pillac, Victor 28 September 2012 (has links)
Les activités de transport jouent un rôle crucial autant dans le domaine de la production que dans celui des services. En particulier, elles permettent d’assurer la distribution de biens et de services entre fournisseurs, unités de production, entrepôts, distributeurs, et clients finaux. Plus spécifiquement, les problèmes de tournées de véhicules (VRP) considèrent la mise au point d’un ensemble de tournées de coût minimal servant la demande en biens ou en services d’un ensemble de clients distribués géographiquement, tout en vérifiant un ensemble de contraintes opérationnelles. Alors qu’il s’agissait d’un problème statique, des avancées technologiques récentes permettent aux organisations de gérer leur flotte de véhicules en temps réel. Cependant, ces nouvelles technologies introduisent également une plus grande complexité dans les tâches de gestion de flotte, révélant une demande pour des outils d’aide à la décision dédiés aux problèmes de tournées de véhicules dynamiques. Dans ce contexte, les contributions de la présente thèse de doctorat s’organisent autour de trois axes : (i) elle présente un état de l’art détaillé des problèmes de tournées dynamiques; (ii) elle introduit des frameworks d’optimisation génériques adaptés à une grande variété de problèmes ; (iii) elle définit un problème de tournées novateur et aux nombreuses applications. / Within the wide scope of logistics management,transportation plays a central role and is a crucialactivity in both production and service industry.Among others, it allows for the timely distributionof goods and services between suppliers, productionunits, warehouses, retailers, and final customers.More specifically, Vehicle Routing Problems(VRPs) deal with the design of a set of minimal costroutes that serve the demand for goods orservices of a set of geographically spread customers,satisfying a group of operational constraints.While it was traditionally a static problem, recenttechnological advances provide organizations withthe right tools to manage their vehicle fleet in realtime. Nonetheless, these new technologies alsointroduce more complexity in fleet managementtasks, unveiling the need for decision support systemsdedicated to dynamic vehicle routing. In thiscontext, the contributions of this Ph.D. thesis arethreefold : (i) it presents a comprehensive reviewof the literature on dynamic vehicle routing ; (ii)it introduces flexible optimization frameworks thatcan cope with a wide variety of dynamic vehiclerouting problems ; (iii) it defines a new vehicle routingproblem with numerous applications.
693

Effective Vulnerability Management for Small Scale Organisations in Ghana

Lartey, Jerry January 2019 (has links)
Most Small and Medium scale Enterprises (SMEs) in Ghana are notparticularly anxious about the consequences of inadequacy or lack of anyform of vulnerability management operation in their normal businesspractices. This case study research explores how a local Internet ServiceProvider (ISP) in Ghana and its local client-base can manage vulnerabilitieswith a targeted patch management practise integrated into their operations.To answer the research question “How can a SME local Internet ServiceProvider (ISP) in Accra, Ghana, assist their local customer base to integrateeffective cybersecurity vulnerability management into their operations?“,This case study comprised the Subject Matter Expert of one local ISP as well as4 other technical Subject Matter Experts of the ISP’s clients about their patchmanagement operations. This case study research revealed that most SMEs donot consider vulnerability management as a key concern in the operation oftheir organisation and therefore, proposes a way to highlight the importanceof vulnerability management whiles doing so at a cost-effective manner. Theimplications of targeted cybersecurity patch management for the local ISP andtheir client-base is also addressed by this thesis research.
694

How does Open Source Software contribute to socio-economic development? An investigation of Open Source Software as an alternative approach to technology diffusion, adoption and adaptation for health information systems development and socio-economic impact in Mozambique

Emdon, Heloise 25 November 2010 (has links)
Abstract Developing countries are net importers of intellectual property products and open source software (OSS) production is one way in which local socio-economic development can take place. The public goods characteristics of OSS are contested and this study investigates whether in a developing country context OSS is a pure public good that can be locally appropriated and not exclude any users or producers from doing so. This case study of an OSS public good finds that it does not have all the characteristics of a pure good, that there is a role for a sponsor, and in particular the importance of copyright protection of derivatives in order to ensure that the source code does not fall out of fashion and use. Having explored that, however, there is further evidence that OSS collaborative learning is both publically and personally beneficial for developing country computer programmers. Furthermore, the state benefits from the improved benefits of health information systems made possible through the appropriation of this model of learning.
695

Controlador fuzzy de código aberto para uso em controladores programáveis. / Open source fuzzy controller for use in programmable logic controller.

Legaspe, Edinei Peres 12 December 2012 (has links)
Sistemas de controle fuzzy são amplamente empregados na indústria de controle de processos. Normalmente controlando variáveis analógicas, tais como pressão, temperatura, vazão, posição e velocidade. Hoje existem diversas soluções de mercado que permitem o uso da lógica fuzzy em CPs (Controladores programáveis). Porém essas soluções são proprietárias e de custo elevado. Adicionalmente existe a norma IEC 61131-7, introduzida no ano de 2000, que especifica sistemas fuzzy em CPs, onde a mesma define um conjunto de regras que permite a definição de algoritmos fuzzy independente do hardware de um fabricante de CPs. A adoção da norma IEC 61131-7 não vem acontecendo de uma maneira rápida, devido a diversos fatores, mas principalmente, por já existirem soluções proprietárias e personalizadas fornecidas pelos fabricantes de CPs. Portanto, a contribuição deste trabalho é um método de desenvolvimento de controladores fuzzy por retroalimentação usando como solução um sistema de código aberto ou livre. Este método propõe o uso de uma arquitetura de controle distribuído envolvendo PCs (Computadores pessoais) e CPs. A construção do controlador fuzzy foi feita em linguagem Java e liberada sobre licença de código aberto, assim permitindo o seu uso de forma gratuita em uma grande variedade de aplicações industriais. O método é baseado na norma IEC 61131-7 para a aplicação da lógica fuzzy em sistemas de automação industrial. Diversos testes foram realizados, tais como testes de mesa do software de controle, e até em uma planta real para validação de software de controle em operação real. Com os resultados dos testes foram obtidas diversas curvas de resposta no tempo, que permitem a avaliação do controlador e do software de controle. Após a execução dos testes e verificado o comportamento obtido pelas curvas, foi constatada a compatibilidade do software construído com a norma IEC 61131-7, assim permitindo o seu uso em outras aplicações. / Fuzzy control systems are largely applied at the processes control industry, usually controlling analogic variables, such as, pressure, temperature, outflow, position and speed. Nowadays, there are several market solutions which allow the Fuzzy Logic usage in PLCs (Programmable Logic Controllers), therefore, these solutions are proprietary and have a high cost. Additionally, there is the IEC 61131-7 standard, introduced in 2000, which specifies Fuzzy systems in PLCs. It defines a set of rules which allow the Fuzzy definition regardless of the hardware from the PLCs manufacturer. The adoption of the IEC 61131-7 standard is not happening effectively, due to many factors, but mainly because there are already proprietary and customized solutions provided by the PLCs manufacturers. The contribution provided by this report, is a method of Fuzzy control development by feedback using as solution, a free or open source code system. This method proposes the usage of a distributed control architecture involving both PCs (Personal Computers) and PLCs. The building of the Fuzzy controller was made in Java language and released under open source code license, allowing its use to be free in a great variety of industrial applications. The method is based on the IEC 61131-7 standard for the Fuzzy logic application in industrial automation. Several tests were performed, such as, software control table test, and even in a real plant for control software validation in a real operation. With the tests results were obtained quite a few response curves at time, which allow the evaluation of the controller and of the control software. After the tests executions and the verifying of the behavior obtained by the curves, it was stated the compatibility of the built software with the IEC 61131-7 standard, admitting it to be used in other applications.
696

Desenvolvimento do processo de compostagem em unidade descentralizada e proposta de software livre para o gerenciamento municipal dos resíduos sólidos domiciliares / Development of decentralized composting plants and open source software proposal to municipal solid waste management

Massukado, Luciana Miyoko 22 August 2008 (has links)
A presente pesquisa teve como objetivos desenvolver o processo de compostagem dos resíduos sólidos, previamente separados na origem e, propor um software livre para o gerenciamento municipal de resíduos sólidos domiciliares. O processo de compostagem se desenvolveu em uma unidade descentralizada experimental, localizada no município de São Carlos, com capacidade para tratar 4 t/mês de resíduos orgânicos. A análise da qualidade do composto foi realizada segundo parâmetros físicos, químicos e microbiológicos. Os resultados indicaram que o composto atende à maioria dos limites estabelecidos pela legislação brasileira, principalmente, com relação à concentração de metais pesados (Cd < 0.5, Pb = 1.3, Cr = 17.4, As < 0.5, Hg < 0.5, Se < 0.5 e Ni = 0.8, em mg/kg) e presença de organismos patogênicos. No entanto, quando esse composto foi submetido a ensaio ecotoxicológico teste agudo em minhocas da espécie Eisenia andrei - constatou-se toxicidade do mesmo, com taxas de mortalidade significativas (P<0.05) a partir da concentração de 16% de composto em solo artificial tropical(TAS), o que significa uma dose de 60 t/ha. A alta condutividade elétrica do composto (CE = 7,48 mS/cm) foi considerada a responsável pela toxicidade do mesmo, uma vez que os teores de metais pesados estiveram muito abaixo dos limites estabelecidos pela legislação. O software livre desenvolvido nesta pesquisa foi denominado SIMGERE - simulação para a gestão de resíduos sólidos - que permite ao usuário simular a vida útil do aterro sanitário a partir da proposição de diferentes cenários de gerenciamento de resíduos sólidos domiciliares. Como estudo de caso aplicou-se o SIMGERE para estimar a vida útil do novo aterro sanitário de São Carlos/SP a partir da simulação de 27 cenários, nos quais foram alteradas as taxas de produção per capita de resíduos (0; 0,5 e 1,0% a.a.), a eficiência da central de triagem (0,5 e 10% a.a) e da unidade compostagem (0,5 e 10% a.a). Os resultados das simulações apontaram uma vida útil variando entre 17 (pior cenário) e 20 anos (melhor cenário). Pode-se inferir pelas simulações que a variação na produção per capita teve maior influência na vida útil do aterro do que a variação na eficiência da central de triagem e da unidade de compostagem. Esse resultado reforça a importância de se realizar investimentos em campanhas de conscientização da população para reduzir a geração de resíduos. / This research aims to develop a household waste composting in a decentralized composting plant and propose open source software for the municipal solid waste management. The composting process was developed in an experimental decentralized plant in São Carlos, with a 4 tons/month capacity. The output compost quality analysis was made according to physical, chemical and microbiological parameters. Result showed that the compost fulfills most of the safety limits required by the brazilian law (IN 27/2006, MAPA), especially in respect with heavy metal concentrations (Cd < 0.5, Pb = 1.3, Cr = 17.4, As < 0.5, Hg < 0.5, Se < 0.5 e Ni = 0.8, em mg/kg) and the presence of pathogens. However, when this compost was submitted to an ecotoxicological test acute test with Eisenia andrei earthworms one verified toxicity in samples with significant mortality (p<0.05) on compost concentrations over 16% in a tropical artificial soil, meaning a 60 ton/ha dose. High electrical conductivity (CE = 7,48 mS/cm) was considered responsible for the compost toxicity. An open source software called SIMGERE - simulation for solid waste management - was developed and allows the user to simulate landfill lifespan from the suggestion of different solid waste scenarios. The software was used to estimate the lifespan of the new landfill in São Carlos/SP from 27 scenarios where waste production rate per capita were changed (0; 0,5 and 1% per year). It was also changed the efficiency of sorting facilities (0,5 e 10%) and composting plants (0,5 e 10%). The results of these simulations showed that the lifespan can range from 17 years (worst case scenario) to 20 years (best case scenario). One can infer by the simulations that changes in the production per capita had a greater influence on the landfill lifespan than changes in efficiency of sorting facilities and of composting plants. This result shows the importance to invest in awareness campaigns to reduce waste.
697

Controlador fuzzy de código aberto para uso em controladores programáveis. / Open source fuzzy controller for use in programmable logic controller.

Edinei Peres Legaspe 12 December 2012 (has links)
Sistemas de controle fuzzy são amplamente empregados na indústria de controle de processos. Normalmente controlando variáveis analógicas, tais como pressão, temperatura, vazão, posição e velocidade. Hoje existem diversas soluções de mercado que permitem o uso da lógica fuzzy em CPs (Controladores programáveis). Porém essas soluções são proprietárias e de custo elevado. Adicionalmente existe a norma IEC 61131-7, introduzida no ano de 2000, que especifica sistemas fuzzy em CPs, onde a mesma define um conjunto de regras que permite a definição de algoritmos fuzzy independente do hardware de um fabricante de CPs. A adoção da norma IEC 61131-7 não vem acontecendo de uma maneira rápida, devido a diversos fatores, mas principalmente, por já existirem soluções proprietárias e personalizadas fornecidas pelos fabricantes de CPs. Portanto, a contribuição deste trabalho é um método de desenvolvimento de controladores fuzzy por retroalimentação usando como solução um sistema de código aberto ou livre. Este método propõe o uso de uma arquitetura de controle distribuído envolvendo PCs (Computadores pessoais) e CPs. A construção do controlador fuzzy foi feita em linguagem Java e liberada sobre licença de código aberto, assim permitindo o seu uso de forma gratuita em uma grande variedade de aplicações industriais. O método é baseado na norma IEC 61131-7 para a aplicação da lógica fuzzy em sistemas de automação industrial. Diversos testes foram realizados, tais como testes de mesa do software de controle, e até em uma planta real para validação de software de controle em operação real. Com os resultados dos testes foram obtidas diversas curvas de resposta no tempo, que permitem a avaliação do controlador e do software de controle. Após a execução dos testes e verificado o comportamento obtido pelas curvas, foi constatada a compatibilidade do software construído com a norma IEC 61131-7, assim permitindo o seu uso em outras aplicações. / Fuzzy control systems are largely applied at the processes control industry, usually controlling analogic variables, such as, pressure, temperature, outflow, position and speed. Nowadays, there are several market solutions which allow the Fuzzy Logic usage in PLCs (Programmable Logic Controllers), therefore, these solutions are proprietary and have a high cost. Additionally, there is the IEC 61131-7 standard, introduced in 2000, which specifies Fuzzy systems in PLCs. It defines a set of rules which allow the Fuzzy definition regardless of the hardware from the PLCs manufacturer. The adoption of the IEC 61131-7 standard is not happening effectively, due to many factors, but mainly because there are already proprietary and customized solutions provided by the PLCs manufacturers. The contribution provided by this report, is a method of Fuzzy control development by feedback using as solution, a free or open source code system. This method proposes the usage of a distributed control architecture involving both PCs (Personal Computers) and PLCs. The building of the Fuzzy controller was made in Java language and released under open source code license, allowing its use to be free in a great variety of industrial applications. The method is based on the IEC 61131-7 standard for the Fuzzy logic application in industrial automation. Several tests were performed, such as, software control table test, and even in a real plant for control software validation in a real operation. With the tests results were obtained quite a few response curves at time, which allow the evaluation of the controller and of the control software. After the tests executions and the verifying of the behavior obtained by the curves, it was stated the compatibility of the built software with the IEC 61131-7 standard, admitting it to be used in other applications.
698

Metodologia para projeto de biorreatores industriais via otimização multiobjetivo com base em parâmetros de desempenho calculados por técnicas de CFD / Methodology for industrial bioreactor design via multiobjective optimization based on performance parameters calculated by CFD techniques

Ansoni, Jonas Laerte 21 May 2015 (has links)
A crescente demanda por biocombustíveis e a concorrência dos combustíveis fósseis torna necessária a otimização dos meios já existentes e o desenvolvimento de novas tecnologias para produção de biocombustíveis, principalmente em projetos envolvendo biorreatores e fotobiorreatores (FBR) industriais. A dinâmica dos fluidos computacional (CFD) vem sendo utilizada em vários trabalhos para o estudo de parâmetros fluidodinâmicos que podem influenciar no rendimento dos processos químicos envolvidos, como tensão de cisalhamento, perfis de velocidade, tempo de residência e a influência da geometria sobre esses parâmetros. Contudo, não existe ainda um número abrangente de trabalhos que utilize técnicas de otimização acopladas com a resolução numérica do problema fluidodinâmico. Em alguns estudos, algoritmos de otimização são utilizados para determinar os melhores coeficientes das reações químicas. No entanto, não há estudos, até o momento, que reportem a otimização multiobjetivo simultânea dos parâmetros geométricos e do escoamento aplicados a equipamentos da indústria sucro-energética. Neste contexto, o presente trabalho de pesquisa tem como objetivo contribuir para o avanço científico e tecnológico através da implementação de um software aberto (PyCFD-O) que permita o acoplamento CFD-otimização e o desenvolvimento das bases de uma metodologia de projeto otimizado bem como de operação de biorreatores e FBRs de escala industrial. O PyCFD-O foi testado em dois estudos de caso que podem ser estendidos a um fermentador contínuo e um FBR. Os parâmetros geométricos de ambos os reatores foram otimizados de forma a minimizar simultaneamente a tensão de cisalhamento e a variância da distribuição do tempo de residência. O software PyCFD-O mostrou-se robusto, revelando que o processo global de otimização realiza de fato a busca pela fronteira de Pareto. Além da obtenção das geometrias otimizadas, também foram discutidos a influência dos parâmetros geométricos na hidrodinâmica do escoamento em ambos os casos. / The growing demand for biofuels and its competition with fossil fuels create the need to optimize the existing resources and development of new technologies for production of biofuels, particularly in projects involving industrial bioreactors and photobioreactors (PBR). Computational fluid dynamics (CFD) has been used in several studies for the study of fluid dynamics parameters that can influence the performance of the chemical process involved, such as shear stress, velocity profiles, residence time and the influence of these parameters on the reactor geometry. However, there are lacks of studies that utilize optimization techniques coupled with the numerical resolution of the fluid dynamic problem. The use of optimization algorithms has been reported in some cases, but there have not been reports on studies combining the optimization of flow parameters and multiobjective algorithms to choose ideal geometric parameters applied to the equipment of the sugar-energy industry. In this context, this research project aims to contribute to the advancement of scientific and technological knowledge trhough the implementation of open source software (PyCFD-O) for the CFD-optimization coupling and the development of the bases of a methodology for optimal design and operation of industrial scale bioreactors and PBR. The PyCFD-O software was tested in two case studies with characteristics that can be extended to a continuos fermenter and PBR. The geometric parameters of both reactors were simultaneously optimized in order to minimize the shear stress and the variance of residence time distribuition. The PyCFD-O software showed robustness, revealing that overall optimization process actually performs the search of Pareto frontier. In addition to the geometry optimization, the influence of the geometrical parameters of the hydrodynamic of the flow was discussed in both case studies.
699

Open Source Enterprise Service Bus : Analyzing impact and value in a large organization

Bagherinia, Sharareh January 2013 (has links)
System integration is a challenging task for large organizations since they must manage complex IT infrastructures, and utilize hundreds of applications that cause a myriad of complications as a result of rapidly evolving systems and technologies. Over time customer requirements and the automation of internal business functions forced the gigantic service providers to develop and buy applications for different purposes. Not many years before, the applications in an organization were usually separated silos, specifically designed to answer a particular problem. However, this way of working was not efficient. It is not impossible to design one application that runs the total business, however, in reality it can&apos;t respond to all the needs inside an organization. In most cases the applications need to interact with each other and to reuse functionalities or data. At this point the concept of integrating systems first came to existence.The progress in computer science and information technology has also affected the way that integration between applications was developed and designed over the years. This shows that there&apos;s always some new method that should be studied and investigated. In recent years, the Enterprise Service Bus has come to the market and there are many vendors in the market claiming that they have produced the exact solution needed for requirements of organizations.In this work, the attempt was to construct an understanding of the Enterprise Application Integration practices and methods which have been utilized over the years. Mixed methods research a combination of interviews and questionnaire, and Design Science Research methods were used to generate empirical results. While the first two methods was used to supply the input for challenges of system integration, the DSR build and evaluate method was employed to test the ESB product. The criteria for the test were developed mostly as the outcome of interviews and the questionnaire as the main challenge. The aim was to verify efficiency and effectiveness of the selected and proposed ESB under special designed DSR build and evaluate phases.As a result of both theoretical and empirical studies in combination with selection of different methods in Information System research, the work presents a knowledge foundation for organizations with the aim to make a change in their current system integration practices and patterns utilizing approaches facilitated by ESB products.
700

Desenvolvimento de máquina universal de ensaios mecânicos portátil de baixo custo para fins didáticos utilizando o conceito open-source. /

Nakazato, Anderson Zenken January 2019 (has links)
Orientador: Luis Rogerio de Oliveira Hein / Resumo: Neste trabalho é apresentado o projeto e construção de uma Máquina Universal de Ensaios Mecânicos portátil, didática, de baixo custo, fácil construção seguindo a filosofia open-source com o intuito de dar suporte ao ensino de Mecânica e Resistência do Materiais. O equipamento foi projetado para ser construído com perfis modulares de alumínio e executado em uma oficina de ensino técnico em mecânica. A máquina é capaz aplicar de forma segura um carregamento máximo de 10 kN tanto em tração quanto em compressão, se mover em velocidades que variam de 0,5 a 70 mm/min com uma resolução no deslocamento de 0,57 μm a um custo total de US$ 1,000.00 incluindo material e fabricação. A máquina é controlada por uma placa Arduino® UNO, opera com acionamento eletromecânico, a aplicação de carga é feita por meio de fusos trapezoidais, a aquisição do deslocamento e velocidade da trave é feita por codificadores de quadratura e o controle de velocidade é feito por controle (Proporcional, Integral e Derivativo) PID e é capaz de realizar ensaios de tração, mas pode ser adaptada para outros ensaios como compressão, flexão e dobramento, entre outros. / Abstract: In this work is presented the design and construction of an easy to build low-cost portable Universal Testing Machine for educational purposes using the open-source philosophy. The intention of this project is to support the teaching in the subjects of Mechanics and Mechanics of Materials. The hardware was designed to be constructed with modular aluminum profiles and built in a conventional Mechanics Technical and Vocational Education and Training Laboratory. The machine can apply safely a maximum load of 10kN in both, traction and compression, move precisely in a range of speed from 0.5 to 70 mm/min with a resolution of 0,57 μm in a total cost of US$ 1,000.00 including necessary material and fabrication. The machine is controlled by an Arduino® UNO board, operated with an electromechanical activation. The loading is applied by trapezoidal lead screws, the displacement and speed acquisition are done by quadrature encoder and the speed is controlled by Proportional, Integral and Derivative (PID) control, it is capable do perform tensile tests, but may be adapted to other tests like compression, flexure and bending, and others. / Mestre

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