927 resultados para Elementary shortest path with resource constraints


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The use of the Design by Analysis (DBA) route is a modern trend in pressure vessel and piping international codes in mechanical engineering. However, to apply the DBA to structures under variable mechanical and thermal loads, it is necessary to assure that the plastic collapse modes, alternate plasticity and incremental collapse (with instantaneous plastic collapse as a particular case), be precluded. The tool available to achieve this target is the shakedown theory. Unfortunately, the practical numerical applications of the shakedown theory result in very large nonlinear optimization problems with nonlinear constraints. Precise, robust and efficient algorithms and finite elements to solve this problem in finite dimension has been a more recent achievements. However, to solve real problems in an industrial level, it is necessary also to consider more realistic material properties as well as to accomplish 3D analysis. Limited kinematic hardening, is a typical property of the usual steels and it should be considered in realistic applications. In this paper, a new finite element with internal thermodynamical variables to model kinematic hardening materials is developed and tested. This element is a mixed ten nodes tetrahedron and through an appropriate change of variables is possible to embed it in a shakedown analysis software developed by Zouain and co-workers for elastic ideally-plastic materials, and then use it to perform 3D shakedown analysis in cases with limited kinematic hardening materials

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Thesis (Ph.D.)--University of Washington, 2016-08

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Enquadramento: As IPSS debatem-se com constrangimentos de ordem financeira que podem ameaçar o seu desempenho. O Estado é o seu maior financiador, mas a tendência de diminuição dos apoios públicos impõe às IPSS encontrem outras formas de financiamento. As IPSS devem garantir a sua sustentabilidade financeira através da diversificação das fontes de financiamento (aumento do financiamento privado) e da implementação de estratégias de redução de custos e aumento das receitas. A gestão dos recursos das IPSS deve ser realizada de uma forma eficiente e eficaz, com vista à construção de uma organização sustentável que cumpra a sua missão e atinja os seus objetivos de carácter social. Objetivos: O objetivo geral do estudo é o seguinte: identificar as estratégias de financiamento que fomentam a sustentabilidade das IPSS. Os objetivos específicos são os seguintes: (1) Conhecer a tipologia das fontes de financiamento das IPSS; (2) Identificar os benefícios e os riscos da diversificação das fontes de financiamento das IPSS; (3) Analisar as fontes de receitas e de custos das IPSS; (4) Identificar os fatores que contribuem para vulnerabilidade financeira das IPSS; (5) Identificar as ações das IPSS que visam uma melhoria da sua sustentabilidade financeira. Métodos: Estudo de caso de 4 IPSS, com utilização de entrevista semi-estruturada (9 entrevistas) e análise documental. Recurso ao software NVivo 10 para categorização dos dados e à análise de conteúdo para interpretação dos dados recolhidos. Resultados:Os Acordos de Cooperação com a Segurança Social são a melhor estratégia para garantir a sustentabilidade financeira das IPSS. Estas desenvolvem um conjunto de ações que visam a melhoria da sua sustentabilidade económica, tais como, a rentabilização de recursos, a redução de despesas, o desenvolvimento de serviços de valor acrescentado e a angariação de recursos. As IPSS sentem necessidade de diversificar as fontes de financiamento (desenvolvimento de atividades complementares como fonte de receita) e apresentam preocupações relacionadas com o cumprimento da sua missão social (intervenção orientada para as necessidades dos stakeholders). Implicações:O estudo sugere a importância das IPSS diversificarem as suas fontes de financiamentoe explorar iniciativas de carácter privado que permitam criar lucro para desenvolver os objetivos e a missão da organização. Recomenda-se a replicação do estudo com uma amostra mais alargada.

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We propose three research problems to explore the relations between trust and security in the setting of distributed computation. In the first problem, we study trust-based adversary detection in distributed consensus computation. The adversaries we consider behave arbitrarily disobeying the consensus protocol. We propose a trust-based consensus algorithm with local and global trust evaluations. The algorithm can be abstracted using a two-layer structure with the top layer running a trust-based consensus algorithm and the bottom layer as a subroutine executing a global trust update scheme. We utilize a set of pre-trusted nodes, headers, to propagate local trust opinions throughout the network. This two-layer framework is flexible in that it can be easily extensible to contain more complicated decision rules, and global trust schemes. The first problem assumes that normal nodes are homogeneous, i.e. it is guaranteed that a normal node always behaves as it is programmed. In the second and third problems however, we assume that nodes are heterogeneous, i.e, given a task, the probability that a node generates a correct answer varies from node to node. The adversaries considered in these two problems are workers from the open crowd who are either investing little efforts in the tasks assigned to them or intentionally give wrong answers to questions. In the second part of the thesis, we consider a typical crowdsourcing task that aggregates input from multiple workers as a problem in information fusion. To cope with the issue of noisy and sometimes malicious input from workers, trust is used to model workers' expertise. In a multi-domain knowledge learning task, however, using scalar-valued trust to model a worker's performance is not sufficient to reflect the worker's trustworthiness in each of the domains. To address this issue, we propose a probabilistic model to jointly infer multi-dimensional trust of workers, multi-domain properties of questions, and true labels of questions. Our model is very flexible and extensible to incorporate metadata associated with questions. To show that, we further propose two extended models, one of which handles input tasks with real-valued features and the other handles tasks with text features by incorporating topic models. Our models can effectively recover trust vectors of workers, which can be very useful in task assignment adaptive to workers' trust in the future. These results can be applied for fusion of information from multiple data sources like sensors, human input, machine learning results, or a hybrid of them. In the second subproblem, we address crowdsourcing with adversaries under logical constraints. We observe that questions are often not independent in real life applications. Instead, there are logical relations between them. Similarly, workers that provide answers are not independent of each other either. Answers given by workers with similar attributes tend to be correlated. Therefore, we propose a novel unified graphical model consisting of two layers. The top layer encodes domain knowledge which allows users to express logical relations using first-order logic rules and the bottom layer encodes a traditional crowdsourcing graphical model. Our model can be seen as a generalized probabilistic soft logic framework that encodes both logical relations and probabilistic dependencies. To solve the collective inference problem efficiently, we have devised a scalable joint inference algorithm based on the alternating direction method of multipliers. The third part of the thesis considers the problem of optimal assignment under budget constraints when workers are unreliable and sometimes malicious. In a real crowdsourcing market, each answer obtained from a worker incurs cost. The cost is associated with both the level of trustworthiness of workers and the difficulty of tasks. Typically, access to expert-level (more trustworthy) workers is more expensive than to average crowd and completion of a challenging task is more costly than a click-away question. In this problem, we address the problem of optimal assignment of heterogeneous tasks to workers of varying trust levels with budget constraints. Specifically, we design a trust-aware task allocation algorithm that takes as inputs the estimated trust of workers and pre-set budget, and outputs the optimal assignment of tasks to workers. We derive the bound of total error probability that relates to budget, trustworthiness of crowds, and costs of obtaining labels from crowds naturally. Higher budget, more trustworthy crowds, and less costly jobs result in a lower theoretical bound. Our allocation scheme does not depend on the specific design of the trust evaluation component. Therefore, it can be combined with generic trust evaluation algorithms.

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Relatório de Estágio apresentado à Escola Superior de Educação do Instituto Politécnico de Castelo Branco para cumprimento dos requisitos necessários à obtenção do grau de Mestre em Educação Pré-Escolar e Ensino do 1.º Ciclo do Ensino Básico.

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O presente trabalho visa conhecer o nível de notoriedade dos produtos tradicionais de origem animal (DOP e IGP) do Alentejo no mercado consumidor. Este objectivo foi alcançado através da realização de revisão bibliográfica com recurso às fontes secundárias disponíveis e de fontes primárias, nomeadamente de um questionário de avaliação da notoriedade dos produtos tradicionais (DOP e IGP) de origem animal do Alentejo expressamente desenvolvido para o efeito. A informação obtida permitiu caracterizar a oferta dos produtos tradicionais de origem animal do Alentejo, em termos quantitativos, qualitativos e diversidade, enquadrar teoricamente o tema da notoriedade no contexto do comportamento do consumidor e do marketing agro-alimentar e identificar os procedimentos metodológicos a serem utilizados e delineamento do trabalho de investigação. A análise dos dados recolhidos por inquérito, tratados com recurso a software e técnicas estatísticas descritivas, permitiram retirar conclusões relevantes, tais como a baixa notoriedade dos produtos DOP e IGP, o produto com mais notoriedade, Top-of-Mind, a Carnalentejana, entre outros. Foram identificados tanto nas fontes primárias como nas secundárias aspectos em comum: uma baixíssima notoriedade dos produtos certificados e uma preocupação e necessidade em haver mais acções de divulgação destes produtos. Dos 33 produtos certificados de origem animal do Alentejo, apuraram-se que apenas 26 se encontram a ser comercializados e em que muitos casos os agrupamentos remetem para os produtores a responsabilidade da promoção dos produtos. Foram ainda identificados tópicos para futuras pesquisas e para acções de marketing tendentes a melhorar a notoriedade dos produtos tradicionais de origem animal do Alentejo no mercado. ABSTRACT; The present work aims to know the level of renown of the traditional products of animal origin (DOP and IGP) of the Alentejo in the consumer market. This objective was reached through the realization of bibliographical revision with resource to the available secondary fountains and of primary fountains, namely of a questionnaire of evaluation of the renown of the traditional products (DOP and IGP) of animal origin of the Alentejo definitely developed for the effect. The obtained information allowed to characterize the offer of the traditional products of animal origin of the Alentejo, in quantitative, qualitative terms and diversity, to fit theoretically the subject of the renown in the context of the behavior of the consumer and of the food-rough marketing and to identify the methodological proceedings being used and delineation of the work of investigation. The analysis of the data gathered by inquiry, treated with resource the software and descriptive statistical techniques, allowed there withdrew relevant conclusions, such as the low renown of the products DOP and IGP, the product with more renown, Top-of-Mind, was the Carnalentejana, between others. Aspects were identified so much in the primary fountains how in secondary in common: a low renown of the certified products and a preoccupation and necessity in having more actions of spread/promotion of these products. Of 33 products made sure of animal origin of the Alentejo, they perfected that you punish 26 they are being marketed and in what many cases the groupings send for the producers the responsibility of the promotion of the products. Topics were still identified for future inquiries and for tending actions of marketing to improve the renown of the traditional products of animal origin of the Alentejo in the market.

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O relatório apresenta o trabalho desenvolvido durante o estágio na Câmara Municipal de Ferreira do Alentejo, objetivado pela obtenção do grau de mestre em Arquitetura Paisagista. Este trabalho pretende valorizar os princípios adquiridos ao longo do percurso académico em licenciatura e mestrado de Arquitetura Paisagista, na ilustre Universidade de Évora, e dar resposta ao objetivo proposto pela entidade acolhedora no presente estágio – a proposta de um percurso potenciador da Paisagem no espaço urbano de Ferreira do Alentejo; ABSTRACT: This report presents the work carried out during the internship at the municipality of Ferreira do Alentejo, which was objectified for obtainment of Master degree in Landscape Architecture. This work aims to enrich the principles acquired during the academic path with the graduation and master degree at the Évora University and to respond to the host institution objective for this internship - the proposal for a landscape enhancer pathway in urban areas of Ferreira do Alentejo.

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In recent decades, studies on economics have identified happiness as a life quality indicator that not only accounts for individuals’ socioeconomic improvement but also accounts for their interactions with institutions and public goods, such as personal safety and protection of life. This study examines the determinants of individual happiness of Latin American citizens by focusing on whether the individual had been a victim of a crime in the last twelve months. To do this, a generalized ordered logit with partial constraints is used to analyze data obtained from the Americas Barometer Survey of 2014. The individual self- reported level of life satisfaction is used to study its relationship with having been a victim of a crime during the previous year. The results suggest the existence of a negative relationship between having been a victim of a crime in the past twelve months and being very satisfied with life.

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Energy Conservation Measure (ECM) project selection is made difficult given real-world constraints, limited resources to implement savings retrofits, various suppliers in the market and project financing alternatives. Many of these energy efficient retrofit projects should be viewed as a series of investments with annual returns for these traditionally risk-averse agencies. Given a list of ECMs available, federal, state and local agencies must determine how to implement projects at lowest costs. The most common methods of implementation planning are suboptimal relative to cost. Federal, state and local agencies can obtain greater returns on their energy conservation investment over traditional methods, regardless of the implementing organization. This dissertation outlines several approaches to improve the traditional energy conservations models. Any public buildings in regions with similar energy conservation goals in the United States or internationally can also benefit greatly from this research. Additionally, many private owners of buildings are under mandates to conserve energy e.g., Local Law 85 of the New York City Energy Conservation Code requires any building, public or private, to meet the most current energy code for any alteration or renovation. Thus, both public and private stakeholders can benefit from this research. The research in this dissertation advances and presents models that decision-makers can use to optimize the selection of ECM projects with respect to the total cost of implementation. A practical application of a two-level mathematical program with equilibrium constraints (MPEC) improves the current best practice for agencies concerned with making the most cost-effective selection leveraging energy services companies or utilities. The two-level model maximizes savings to the agency and profit to the energy services companies (Chapter 2). An additional model presented leverages a single congressional appropriation to implement ECM projects (Chapter 3). Returns from implemented ECM projects are used to fund additional ECM projects. In these cases, fluctuations in energy costs and uncertainty in the estimated savings severely influence ECM project selection and the amount of the appropriation requested. A risk aversion method proposed imposes a minimum on the number of “of projects completed in each stage. A comparative method using Conditional Value at Risk is analyzed. Time consistency was addressed in this chapter. This work demonstrates how a risk-based, stochastic, multi-stage model with binary decision variables at each stage provides a much more accurate estimate for planning than the agency’s traditional approach and deterministic models. Finally, in Chapter 4, a rolling-horizon model allows for subadditivity and superadditivity of the energy savings to simulate interactive effects between ECM projects. The approach makes use of inequalities (McCormick, 1976) to re-express constraints that involve the product of binary variables with an exact linearization (related to the convex hull of those constraints). This model additionally shows the benefits of learning between stages while remaining consistent with the single congressional appropriations framework.

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O objetivo do presente relatório é realizar uma análise critica sobre o processo de estágio pedagógico em Educação Física, desenvolvido na Escola Secundária com 3º ciclo de Caneças, Caneças, Odivelas, no ano letivo de 2012/2013 e que consistiu na primeira experiência formativa de prática de ensino em contexto real. O desenvolvimento do estágio iniciou-se com alguns condicionalismos provocados por uma situação particular da escola de estágio, que foram ultrapassados pelo bom funcionamento e dinâmica do núcleo de estágio. Verificou-se uma evolução progressiva no desempenho do professor em todas as dimensões da área da organização e gestão do ensino e da aprendizagem. A elaboração do projeto de investigação permitiu fornecer aos professores do Departamento de Educação Física soluções para ultrapassar as dificuldades de lecionação na matéria da dança. O trabalho desenvolvido nas áreas da participação da escola e da relação com a comunidade foram importantes para adquirir e compreender várias funções do professor fora do contexto da sala de aula. Como conclusão, reconhece-se que a reflexão crítica e a perseverança durante o processo formativo foi a base para o trabalho desenvolvido. Através da reflexão final é enfatizado o quanto a qualidade profissional dos professores é importante para o bom processo de ensino-aprendizagem dos alunos, assim como, a persistência e a ambição que o professor deve ter pela melhoria das suas ações.

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Mestrado em Marketing

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In recent years, there has been an enormous growth of location-aware devices, such as GPS embedded cell phones, mobile sensors and radio-frequency identification tags. The age of combining sensing, processing and communication in one device, gives rise to a vast number of applications leading to endless possibilities and a realization of mobile Wireless Sensor Network (mWSN) applications. As computing, sensing and communication become more ubiquitous, trajectory privacy becomes a critical piece of information and an important factor for commercial success. While on the move, sensor nodes continuously transmit data streams of sensed values and spatiotemporal information, known as ``trajectory information". If adversaries can intercept this information, they can monitor the trajectory path and capture the location of the source node. This research stems from the recognition that the wide applicability of mWSNs will remain elusive unless a trajectory privacy preservation mechanism is developed. The outcome seeks to lay a firm foundation in the field of trajectory privacy preservation in mWSNs against external and internal trajectory privacy attacks. First, to prevent external attacks, we particularly investigated a context-based trajectory privacy-aware routing protocol to prevent the eavesdropping attack. Traditional shortest-path oriented routing algorithms give adversaries the possibility to locate the target node in a certain area. We designed the novel privacy-aware routing phase and utilized the trajectory dissimilarity between mobile nodes to mislead adversaries about the location where the message started its journey. Second, to detect internal attacks, we developed a software-based attestation solution to detect compromised nodes. We created the dynamic attestation node chain among neighboring nodes to examine the memory checksum of suspicious nodes. The computation time for memory traversal had been improved compared to the previous work. Finally, we revisited the trust issue in trajectory privacy preservation mechanism designs. We used Bayesian game theory to model and analyze cooperative, selfish and malicious nodes' behaviors in trajectory privacy preservation activities.

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This thesis builds a framework for evaluating downside risk from multivariate data via a special class of risk measures (RM). The peculiarity of the analysis lies in getting rid of strong data distributional assumptions and in orientation towards the most critical data in risk management: those with asymmetries and heavy tails. At the same time, under typical assumptions, such as the ellipticity of the data probability distribution, the conformity with classical methods is shown. The constructed class of RM is a multivariate generalization of the coherent distortion RM, which possess valuable properties for a risk manager. The design of the framework is twofold. The first part contains new computational geometry methods for the high-dimensional data. The developed algorithms demonstrate computability of geometrical concepts used for constructing the RM. These concepts bring visuality and simplify interpretation of the RM. The second part develops models for applying the framework to actual problems. The spectrum of applications varies from robust portfolio selection up to broader spheres, such as stochastic conic optimization with risk constraints or supervised machine learning.

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Lower limb amputation is an event that inevitably changes the lifestyle of the person with a significant impact on quality of life. The socket-type prosthesis entails that the residual limb is in direct contact with the socket which often implies numerous disadvantages. Osseointegrated prosthesis is a solution that avoids skin problems because not include the presence of the socket. In this type of prosthesis, a stem is surgically inserted inside the medullary canal and connected with the external prosthetic limb. Therefore, this thesis aims to highlight and explore the main strengths and problems of osseointegrated prostheses and to examine the role of physical activity, with attention to functional capacity and bone quality. The objectives of the thesis will be developed through 5 studies: (I) A gait analysis of a 44 years-old male patient who underwent surgery for the implantation of an osseointegrated prosthesis; (II) A systematic review to investigate the state of stump bone quality in patients with limb amputations; (III) A systematic review of the technologies involved in such devices has been carried out to identify the most fruitful ones in improving bone quality; (IV) A systematic review investigating the topic of physical activity and bone turnover biomarkers; (V) A systematic review to investigate the effects of physical activity interventions combined with drug treatments on bone biomarkers in people with osteopenia and osteoporosis. The integrated prosthesis is a good solution for people with lower limb amputation who cannot use their traditional socket-type prosthesis. Although many objectives have already been achieved, there are still many aspects that we can improve. These include the creation of a multidisciplinary path that support patients along their path, with particular attention to the pre-surgery and the post-rehabilitation phase that is still lacking even if of fundamental impact in determining the quality of life.

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The thesis investigates two different in vitro aspects of Chlamydia trachomatis (CT). The thesis analyzes the effect of different sugars on CT infectivity. which is investigated on HeLa cells after 2 hour-incubation of elementary bodies (EBs) with glucose, sucrose or mannitol. Sugars effect on EB membrane fluidity is investigated by fluorescence anisotropy measurement, whereas changes in lipopolysaccharide exposure are examined by cytofluorimetric analysis. By Western blot experiments, the phosphorylation state of Focal Adhesion Kinase in cells infected with EBs pre-incubated with sugars it’s explored. Sugar significantly increase infectivity, acting on the EB structure. Sugars induce an increase of EB membrane fluidity, leading to changes in LPS exposure. After incubation with sucrose and mannitol, EBs lead to higher FAK phosphorylation, enhancing activation of anti-apoptotic and proliferative signals in the host. Secondly, the thesis explores the protective effect of different Lactobacilli against CT infection: Lactobacillus crispatus and Lactobacillus reuteri. CT infectivity is evaluated after host cells were treated for 1 hour with diluted supernatant cell-free fraction or with the bacterial cells. Assessed that L.crispatus is more protective than L.reuteri, lactic acid production is evaluated by HPLC. Subsequently Lactate dehydrogenases activity is evaluated by resazurin assay and by LC-MS. Then, D-lactate dehydrogenase specific activity has been investigated by measuring NADH formation. Afterwards, addition of D or L-lactic acid to L.reuteri supernatant has been performed and their effect in promoting protection in the host cells assessed. Then a metabolic analysis has been carried out by real-time measurement of mitochondrial respiration after treatment. Finally, histone acetylation and lactylation, and gene and protein expression of relevant targets, have been investigated. It is shown that the D isomer is more efficient in conferring protection, causing a shift in the host cell metabolic profile and a pattern of histone modifications that changes the expression of important targets.