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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.
331

Um método biobjetivo de alocação de tráfego para veículos convencionais e elétricos / A bi-objective method of traffic assignment for conventional and electric vehicles

Souza, Marcelo de January 2015 (has links)
A busca de soluções para a mobilidade urbana que minimizem a agressão do setor de tráfego e transportes ao meio ambiente está cada vez maior. Os veículos elétricos se posicionam como uma alternativa interessante, pois reduzem a emissão de gases poluentes na atmosfera, a poluição sonora e o consumo de petróleo. No entanto, sua limitada autonomia e a escassez de postos de recarga intimidam sua adoção. Por conta disso, políticas governamentais de incentivo têm sido desenvolvidas para a oferta de benefícios a quem optar por um veículo elétrico. Estima-se que dentro de poucas décadas toda a frota urbana será substituída por veículos dessa natureza. Por isso, é importante entender as mudanças no tempo de viagem e no consumo de energia oriundos da inclusão de veículos elétricos em cenários de tráfego. Trabalhos anteriores estudaram as diferenças entre os mecanismos internos de veículos convencionais e elétricos na determinação destas mudanças. Porém, dadas as características destes últimos, motoristas de veículos elétricos se preocupam com a economia de energia e podem optar por rotas diferentes. Logo, uma análise completa destes impactos deve considerar uma nova distribuição de tráfego. Este trabalho propõe um método biobjetivo de alocação de tráfego que considera o tempo de viagem e o consumo de energia para determinar a distribuição de veículos elétricos em cenários de tráfego urbano. Duas estratégias de distribuição de fluxo são propostas como mecanismos de escolha de rotas. Como parte da alocação de tráfego, é proposto um algoritmo biobjetivo de caminhos mínimos para veículos elétricos. A abordagem apresentada foi aplicada a três cenários distintos, onde percebeu-se uma diminuição de até 80% no consumo total de energia. Em cenários com congestionamento, observou-se um aumento de 10% no tempo de viagem. Já em cenários sem congestionamento o tempo de viagem diminuiu cerca de 2%. A recuperação de energia representa quase 6% da economia total dos veículos elétricos. Além disso, experimentos mostraram que investimentos na eficiência dos veículos elétricos podem resultar em uma economia de até 15% de energia. / The search for urban mobility solutions that minimize the aggression to the environment is increasing. Electric vehicles are an attractive alternative because they reduce greenhouse gas emissions, noise pollution, and oil consumption. However, their limited autonomy and the lack of charging stations restrict their popularization. Therefore, government incentive policies have been developed in order to offer benefits to those who choose an electric vehicle. It is estimated that the entire urban fleet will be replaced by these vehicles in a few decades. Therefore, it is important to understand the changes in travel time and energy consumption from the inclusion of electric vehicles in traffic scenarios. Previous works determined these changes by studying the differences between the internal engine of conventional and electric vehicles. However, given the characteristics of the latter, drivers of electric vehicles care about saving energy and may want to choose different routes. Thus, a complete analysis of these impacts should consider a redistribution of traffic. This work proposes a bi-objective traffic assignment method that considers the travel time and the energy consumption to determine the distribution of electric vehicles in urban traffic scenarios. We introduce two strategies for flow distribution as models of route choice. As a procedure of the traffic assignment method, we propose a bi-objective shortest path algorithm for electric vehicles. Our approach was applied to three different scenarios, which resulted in a decrease of up to 80% in total energy consumption. In congested scenarios, we observe an increase of about 10% in average travel time. In uncongested scenarios, travel time decreases about 2%. Energy recovery is almost 6% of the total savings of electric vehicles. Moreover, experiments have shown that investments in the efficiency of electric vehicles can result in up to 15% of energy savings.
332

Avaliação da escolha de rota dos motoristas frente à cobrança de pedágio e rodovias de qualidades distintas

Zignani, Rita de Cassia January 2007 (has links)
A malha rodoviária brasileira é caracterizada por vias com níveis de qualidade heterogêneos. Em geral, rodovias que possuem cobrança de pedágio apresentam melhor estado de conservação. Essa dissertação tem como objetivo avaliar a escolha de rota de diferentes classes de usuários, considerando-se a cobrança de pedágio e a diferença na qualidade das vias. A avaliação envolveu a realização de duas fases de pesquisa. A primeira fase buscou estimar os valores monetários dos atributos de tempo e distância de viagem através da técnica de Preferência Declarada. A segunda fase utilizou estes valores monetários como parâmetros da função de custo generalizado da modelagem de alocação de tráfego para estimar a escolha de rota dos usuários. A partir da metodologia proposta, um estudo de caso foi realizado em um trecho rodoviário que apresenta uma rodovia pedagiada e uma rota concorrente de menor qualidade sem cobrança. Os resultados da aplicação prática não refletiram os dados de fluxo observados nas rodovias avaliadas. A partir desta constatação, um questionário complementar foi elaborado buscando identificar o comportamento habitual dos usuários na região de estudo. Através dos resultados da pesquisa complementar, verificou-se que a maioria dos entrevistados não possuía conhecimento sobre a rota alternativa. A utilização dos dados provenientes destes usuários na modelagem não se mostrou apropriada, uma vez que sua escolha de rota não é baseada nas relações de tempo, distância e penalidades nas vias, consideradas nos modelos de alocação de tráfego. Com isso, pode-se verificar neste estudo que os princípios e limitações das técnicas e ferramentas utilizadas, bem como de sua utilização conjunta, devem ser avaliados. / The Brazilian road system is characterized by roads with heterogeneous level of quality. Generally, tolled roads present better quality conditions than those not tolled. This work aimed to evaluate the route choice of different user’s classes considering toll collection and roads of different qualities. This evaluation was carried out with a methodology composed of two phases preceded by definition of the study region and the users classes considered. The first phase intended to estimate monetary values of time and distance through the Stated Preference technique. The second phase used these monetary values as parameters in an assignment model generalized cost function to estimate user’s route choice. From the proposal methodology, a case study was carried out in a road stretch that presents a tolled highway and a worse quality and without charge alternative route. The practical application results did not reflected the observed flow data in the evaluated highways. From these results, a complementary questionnaire was elaborated to identify the habitual user’s behavior in the study region. It was observed that the majority of the interviewed ones did not have knowledge of the alternative route. Using these data in the modeling was not appropriate because their route choice is not based in time, distance and road penalties relationship like in the assignment models. Thus, it was verified in this study that the principles and limitation of the used techniques and tools, as well as the joint use of these, might be taken in consideration.
333

Global Population Structure of the Dusky Shark and Geographic Sourcing of Shark Fins from Commercial Markets

Gray, Teagen K. 01 July 2014 (has links)
The dusky shark, Carcharinus obscurus, is a globally distributed, coastal-pelagic species subject to an apparent high level of exploitation. The International Union for the Conservation of Nature (IUCN) lists this species as “Vulnerable” globally, and “Endangered” within western North Atlantic and Gulf of Mexico waters due to an over 80% decline in this region, with no evidence of population recovery. The extensive exploitation of dusky sharks may partly be attributed to the high market value of its fins, but the contribution of individual dusky shark stocks to the fin markets is unknown. This knowledge would be helpful to detect if specific stocks are experiencing disproportionate levels of exploitation. Due to its susceptibility to overfishing, current dire conservation status and need for additional information on its population dynamics, we analyzed the genetic population structure and genetic diversity of the dusky shark (n = 415) across 8 globally distributed locations utilizing 10 nuclear microsatellite loci. The nuclear marker analyses support and extend previously published mitochondrial marker work, identifying a strong divergence among Atlantic and Indo-Pacific samples. Furthermore, nuclear marker results indicate the presence of six genetically discrete management units for dusky sharks, with significant genetic differentiation between the western North Atlantic, South African, and each of three Australian site collections (N, E and W coasts). Discovery of these nuclear microsatellite-defined, smaller geographic scale management units provides a basis for the assignment of market-derived fins to their population of origin with the use of genetic assignment techniques.
334

[en] A SOFTWARE FOR THE MULTIMODAL MULTIPRODUCT FLOW ASSIGNMENTIN FREIGHT TRANSPORTATION / [es] SISTEMA DE FLUJOS MULTIMODAL MULTIPRODUCTO PARA TRANSPORTE DE CARGA / [pt] SISTEMA PARA ALOCAÇÃO DE FLUXOS MULTIMODAL MULTIPRODUTO PARA TRANSPORTE DE CARGA

FABIANO MEZADRE POMPERMAYER 17 July 2001 (has links)
[pt] Esta dissertação de mestrado apresenta o desenvolvimento de um sistema computacional para fazer a alocação de fluxos de transporte de carga multiproduto em uma rede multimodal. Este sistema tem o objetivo de servir como uma ferramenta no planejamento estratégico de transporte. O software foi concebido inicialmente para trabalhar com o ótimo do sistema, minimizando o custo total de transporte na rede. Uma adaptação é sugerida, para que seja possível trabalhar também com o ótimo do usuário, minimizando as rotas individuais dos usuários da rede de transporte. Para fazer a alocação de fluxos multiproduto em uma rede multimodal o software utiliza o algoritmo de Frank-Wolfe que resolve o problema multimodal multiproduto. / [en] This dissertation presents the development of a computer system, wich performs the assignment of multicommodity freight transportation flows on a multimodal network. This systems should be used as a tool in strategic transportation planning. Initially the software the has been conceived to search for the system`s optimum, by minimizing the total transportation cost in the network. The Dissertation proposes an adaptation to make possible for the system to calculate the user`s optimum, by minimizing the costs of the individual paths of the transportation network users. To Implement the multicommodity flow assignment on the multimodal network, the software makes use of na adaptation of the Frank and Wolfe algorithm to solve the multimodal, multicommodity problem. / [es] En desarrollo
335

Specification and Automated Design-Time Analysis of the Business Process Human Resource Perspective

Resinas, Manuel, del-Río-Ortega, Adela, Ruiz-Cortés, Antonio, Cabanillas Macias, Cristina 03 April 2015 (has links) (PDF)
The human resource perspective of a business process is concerned with the relation between the activities of a process and the actors who take part in them. Unlike other process perspectives, such as control flow, for which many different types of analyses have been proposed, such as finding deadlocks, there is an important gap regarding the human resource perspective. Resource analysis in business processes has not been defined, and only a few analysis operations can be glimpsed in previous approaches. In this paper, we identify and formally define seven design-time analysis operations related to how resources are involved in process activities. Furthermore, we demonstrate that for a wide variety of resource-aware BP models, those analysis operations can be automated by leveraging Description Logic (DL) off-the-shelf reasoners. To this end, we rely on Resource Assignment Language (RAL), a domain-specific language that enables the definition of conditions to select the candidates to participate in a process activity. We provide a complete formal semantics for RAL based on DLs and extend it to address the operations, for which the control flow of the process must also be taken into consideration. A proof-of-concept implementation has been developed and integrated in a system called CRISTAL. As a result, we can give an automatic answer to different questions related to the management of resources in business processes at design time.
336

An optimization model using the Assignment Problem to manage the location of parts : Master Thesis at the engine assembly at Scania CV AB

Lundquist, Josefin, O'Hara, Linnéa January 2017 (has links)
A key challenge for manufacturing companies is to store parts in an efficient way atthe lowest cost possible. As the demand of differentiated products increases, togetherwith the fact that old products are not phased out at the same pace, the need of usingstorage space as dynamically as possible becomes vital.Scania’s engine assembly manufactures engines for various automotive vehicles andmarine & industry applications. The variation in engine range in Scania’s offeringleads to the need of holding a vast, and increasing, assortment of parts in the produc-tion. As a consequence, this puts more pressure on the logistics and furnishing withinthe engine assembly.This master thesis aims to facilitate the process of assigning parts’ storage locationsin the most profitable manner through an optimization model, the Location Model, inExcel VBA. Together with the model, suggestions of work methods are presented.By implementing the Location Model at Scania’s engine assembly, 4,98 % of all keptparts are recommended location changes, while resulting in cost savings, for the chosen30-day period. These location changes result in a cost saving of 6,73 % of the totallogistic costs for the same time period.
337

Structural and dynamic features of Sup35 prion fibrils by solid-state NMR spectroscopy / Caractérisation structurale et dynamique des fibrilles du prion Sup35 par spectroscopie RMN du solide

Luckgei, Nina 16 October 2013 (has links)
Les protéines prions sont associées à une classe de maladies neurodégénératives, dont l'encéphalopathie spongiforme transmissible (EST) est la mieux connue. La protéine prion Sup35p représente un tel modèle car elle est non associée à une maladie. Sup35p se compose de trois domaines : un domaine N-terminal qui est responsable de la formation de prion, d'un domaine de milieu (M) qui affiche un degré élevé de flexibilité, et un domaine C-terminal fonctionnel et globulaire. Le fragment Sup35pNM est souvent utilisé comme modèle pour documenter l'assemblage et les propriétés infectieuses de Sup35p. Les études de Sup35p et Sup35pNM par RMN du solide ont révélé d'étonnantes différences structurelles entre les deux cœurs amyloïdes de Sup35p et Sup35pNM. Nos résultats sur Sup35p apportent un nouvel éclairage sur le monde étonnamment diversifié des prions où la variabilité conformationnelle joue un rôle énorme et perturbant. Ils reflètent l'image émergente que les prions sont des unités structurelles complexes. En effet, même s'il affiche une structure très définie, un domaine donné peut adopter des conformations différentes selon les circonstances (en isolation, dans le contexte d'un fragment ou la protéine entière) ou de l'environnement (conditions de tampon, présence de chaperonnes). Nos résultats donnent une explication au niveau moléculaire pour la contractante propension à l'assemblage et l'infectiosité de Sup35pNM et Sup35p, et soulignent l'importance primordiale d'une caractérisation structurale au niveau moléculaire des agrégats utilisés dans des études fonctionnelles / Prion proteins are associated with a class of neurodegenerative diseases, including transmissible spongiform encephalopathy (TSE) which is the best known. The prion protein Sup35p displays a model system because it is not associated with disease. Sup35p consists of three domains: an N-terminal domain which is responsible for the prion formation, a middle domain (M) that displays a high degree of flexibility, and a functional C-terminal domain. Sup35pNM the fragment is often used as a model to document for the assembly and infectious properties of Sup35p. Solid-state NMR studies of Sup35p and Sup35pNM fibrils showed amazing structural differences between the two amyloid cores. Our results shed new light on the surprisingly diverse world of prions where conformational variability plays a huge role. They reflect the emerging picture that prions are complex structural units. Even if it displays a very defined structure, a given field may adopt different conformations depending on the circumstances (in isolation, in the context of the whole protein or fragment) or the environment (buffer conditions, presence of chaperones). Our results provide an explanation at the molecular level for the contrasting propensity assembly and infectivity Sup35pNM and Sup35p, and emphasize the central importance of a structural characterization at the molecular level
338

La cession du contrat de travail / The assignment of the employment contract

Selusi, Sophie 07 December 2015 (has links)
S’inscrivant dans un contexte juridique et économique propice, cette thèse propose une utilisationrenouvelée de la cession de contrat adaptée au rapport de travail. Les finalités de ce mécanismejustifient l’opportunité de sa réception et de sa réalisation augurant son développement. Constatantque ni le législateur, ni le juge, ne font référence au dispositif, un effort de définition est accompli.La cession du contrat de travail est l’opération consistant à changer d’employeur avec l’accord dusalarié sans rupture. Repensées sous le prisme de la cession de contrat, les opérations se situant àla frontière du transfert d’entreprise sont clarifiées et réalisées de manière cohérente.Le particularisme du rapport de travail suppose que soit mis en place un système légal garantissantle consentement du salarié. Instaurant une continuité contractuelle, la mise en œuvre de cetinstrument confirme son utilité. / Within a propitious legal and economic environment, this PhD thesis sheds the light of a suitableand renewed use of the assignment of contract. The purposes of the mechanism foster itsdevelopment. The lack of definition by lawmakers and judges tends to render such workmandatory. The assignment of contract shall be the operation changing of employer by mutualagreement with the employee without any termination. All operations closed to transfer ofundertaking are therefore clarified. The specificity of employment relationship involves a legalregime ensuring the consent of employee. Establishing a contractual continuum, its usefulness isjustified by its implementation.
339

Job Scheduling Considering Both Mental Fatigue and Boredom

Jahandideh, Sina January 2012 (has links)
Numerous aspects of job scheduling in manufacturing systems have been the focus of several studies in the past decades. However, human factors in manufacturing systems such as workers’ mental conditions are still neglected issues and have not received adequate attentions. Job boredom and mental fatigue are both aspects of workers’ mental condition. They affect work performances by increasing sick leave duration and decreasing work productivity. On the other hand, job rotation could be an alternative strategy to cope with such human issues at work. The benefits of job rotation for both employees and firms have been widely recognized in the literature. Although some studies found job rotation as a means to reduce workers' physical work-related traumas, they did not consider the effect of variable mental conditions on workers. Despite the proven importance of boredom and mental fatigue at the workplace, they have not been a combined precise objective of any job rotation problem in current literature. The study of mental conditions proposed in this paper attempts to extend the previous works by addressing new methods and developing a feasible solution to increase manufacturing productivity. A new job scheduling program has been designed specifically which combines a new job rotation model and a job assignment method.
340

Taking Care of Global Employees and Knowledge Transfer / Péče o globální zaměstnance a tok znalostí

Štěrbová, Zuzana January 2008 (has links)
The thesis on the topic of Taking Care of GE and Knowledge Transfer in Company X has examined the practice in the field of the global assignments of the company X hand in hand with a qualitative research method among the GE of X. First, theoretical proposals were introduced and analysed. Then they were connected with the results of the research and discussed and proposals were made for optimising of the care taking about the GE and for releasing the knowledge flow in X.

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