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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.
491

Mativation : En kvantitativ studie om elevers värdering av lärares motivationsskapande ledarskap / Mathivation : A quantitative study on students' evaluation of teachers' motivational leadership

Elheim, Wille, Iversen, Edvin January 2024 (has links)
Denna kvantitativa studie fokuserar på att bidra med kunskap om hur pojkar och flickor i årskurs 6 värderar olika ledarskapsbeteende utifrån Path-goal theory. Värderingen av de olika ledarskapsbeteenden skedde med avseende för att skapa motivation i ämnet matematik. Studien har samlat in svar från 110 elever i årskurs 6 på ett frågeformulär med utgångspunkt i Northouse (2018) enkät relaterade till Path-goal theory. Vid analysen för arbetet genomfördes en deskriptiv analys samt ett Chi2-test. Vårt resultat har visat att elever i årskurs 6 värderar ett vägledande ledarskap högst, följt av prestationsorienterade, sen stödjande och till sist deltagande. Chi2-testet visar även på en statistisk signifikant skillnad i värdering av de olika ledarskapsbeteenden mellan flickor och pojkar. Nollhypotesen, om att pojkar och flickor värderar ledarskapsbeteendena lika, kunde vid testet förkastas.
492

Coverage path planning for UAVs in search missions

Navarro, Alonso, Haracic, Avdo January 2024 (has links)
A time-effective coverage path can be decisive in catastrophic and war scenarios for saving countless lives where UAVs are used to scan an area looking for an objective. Given an area shaped as a polygon, a quadratic decomposition method is used to discretize the area into nodes. A model of the optimization problem constraint is created and solved using mixed-integer linear programming, taking into consideration simple dynamics and coverage path planning definitions. Simulations in different scenarios are presented, showing that the presence of no-fly zones can negatively affect the coverage time. The relationship between coverage time and the number of UAVs employed is nonlinear and converges to a constant value. The result has a direct impact on the evaluation of benefits and the cost of adding UAVs to a search mission.
493

La conjecture de partitionnement des chemins

Champagne-Paradis, Audrey 05 1900 (has links)
Soit G = (V, E) un graphe simple fini. Soit (a, b) un couple d’entiers positifs. On note par τ(G) le nombre de sommets d’un chemin d’ordre maximum dans G. Une partition (A,B) de V(G) est une (a,b)−partition si τ(⟨A⟩) ≤ a et τ(⟨B⟩) ≤ b. Si G possède une (a, b)−partition pour tout couple d’entiers positifs satisfaisant τ(G) = a+b, on dit que G est τ−partitionnable. La conjecture de partitionnement des chemins, connue sous le nom anglais de Path Partition Conjecture, cherche à établir que tout graphe est τ−partitionnable. Elle a été énoncée par Lovász et Mihók en 1981 et depuis, de nombreux chercheurs ont tenté de démontrer cette conjecture et plusieurs y sont parvenus pour certaines classes de graphes. Le présent mémoire rend compte du statut de la conjecture, en ce qui concerne les graphes non-orientés et ceux orientés. / Let G = (V,E) be a finite simple graph. We denote the number of vertices in a longest path in G by τ(G). A partition (A,B) of V is called an (a,b)−partition if τ(⟨A⟩) ≤ a and τ(⟨B⟩) ≤ b. If G can be (a,b)−partitioned for every pair of positive integers (a, b) satisfying a + b = τ (G), we say that G is τ −partitionable. The following conjecture, called The Path Partition Conjecture, has been stated by Lovász and Mihók in 1981 : every graph is τ−partitionable. Since that, many researchers prove that this conjecture is true for several classes of graphs and digraphs. This study summarizes the different results about the Path Partition conjecture.
494

Exotic order in magnetic systems from Majorana fermions

Bennett, Edmund January 2016 (has links)
This thesis explores the theoretical representation of localised electrons in magnetic systems, using Majorana fermions. A motivation is provided for the Majorana fermion representation, which is then developed and applied as a mean-field theory and in the path-integral formalism to the Ising model in transversal-field (TFIM) in one, two and three dimensions, on an orthonormal lattice. In one dimension the development of domain walls precludes long-range order in discrete systems; this is as free energy savings due to entropy outweigh the energetic cost of a domain wall. An argument due to Peierls exists in 2D which allows the formation of domains of ordered spins amidst a disordered background, however, which may be extended to 3D. The forms of the couplings to the bosons used in the Random Phase Analysis (RPA) are considered and an explanation for the non-existence of the phases calculated in this thesis is discussed, in terms of spare degrees of freedom in the Majorana representation. This thesis contains the first known application of Majorana fermions at the RPA level.
495

Coalizões e preferências políticas na crise hídrica da Região Metropolitana de São Paulo: o paradigma da gestão da oferta / Coalitions and political preferences in the water crisis of São Paulo Metropolitan Area: the hard path paradigm

Spinola, Ana Lúcia Gerardi 03 October 2018 (has links)
O aumento das regiões de escassez de água ao redor do mundo traz à tona questionamentos acerca de como a sociedade moderna utiliza a água e de que forma isso afetará a disponibilidade hídrica futura. Os resultados políticos, que têm influência significativa no agravamento destes eventos, são moldados por estratégias que refletem as preferências políticas dos atores envolvidos na gestão da água. Exemplos dessas estratégias são: a gestão da oferta, a gestão da demanda e o water soft path. A gestão da oferta é caracterizada pela dependência quase sistemática da busca por novas fontes de água. Enquanto a água estiver disponível para ser alocada, mesmo de locais distantes, há pouca discussão sobre medidas alternativas. A política de coalizão existe quando pessoas de dentro e fora do governo se mobilizam e interagem para traduzir suas crenças e ideias em ações concretas. Estas interações podem resultar em mudança ou na continuidade política. A pesquisa visou responder à questão de quais coalizões são identificadas no subsistema de gestão da água na crise hídrica da RMSP e quais abordagens de gestão essas utilizam. Para isso, valeu-se do Modelo de Coalizões de Defesa como ferramenta teórica, bem como de ferramentas computacionais de análise de redes sociais e de frequência de palavras como ferramentas metodológicas. Esse trabalho explorou a reafirmação da coalizão político-tecnocrática ao longo do período da crise hídrica. Essa coalizão foi articulada em torno do governo do Estado e de técnicos e gestores da Companhia Estadual de Saneamento; de forma que eles conseguiram centralizar as decisões em um grupo restrito de atores políticos e traduzir suas ideias em planos de obras emergenciais, guiados pelo paradigma da gestão da oferta. / The increase of water scarcity regions around the world raises questions about how modern society uses water and how this could affect future water availability. Political outcomes, which ones have a significant influence on the aggravation of these events, are shaped by strategies that reflect the political preferences of stakeholders involved in water management. Examples of these strategies are: supply management, demand management and water soft path. Supply- side management is characterized by the dependence from new water sources exploration. While water is available to be allocated, even from distant locations, there is few discussions about alternative measures. Coalition policy exists when people inside and outside the government mobilize and interact to translate their beliefs and ideas into concrete actions. These interactions can result in change or political continuity. The present research aims to answer the follow question: which policy coalitions could be identified into water policy subsystem during the water crisis in São Paulo Metropolitan Area? In order to achieve this goal, we applied The Advocacy Coalition Framework as theoretical tool and computational network analysis and word frequency as methodology. This work explores the politic-technocrat coalition continuity during water crisis. This coalition is articulated around State Government and State Sanitary Company, so they can translate their ideas in contingence plans underpinning by water supply paradigm.
496

Reconceitualizando o Institucionalismo Histórico: path dependence, agencia e mudança institucional / Reconceptualizing the Historical Institutionalism: path dependence, agency and institutional change

Cesaris, Luis Enrique Urtubey de 09 October 2009 (has links)
O núcleo desta dissertação é desenvolver um conceito de path dependence mais parcimonioso, coerente e útil, seja teoricamente ou em estudos empíricos. Neste sentido, o insight fundamental é que se partimos de uma conceitualização mais dinâmica, baseada mais em externalidades negativas do que em rendimentos crescentes, o conceito de path dependence pode ser inerentemente mais operacionalizável, robusto e ressoar melhor com a literatura e os estudos Institucionalistas Históricos. O conceito de path dependence pode também ser mais compatível com várias elaborações realizadas dentro do próprio Institucionalismo Histórico sobre questões como mudança institucional, mecanismos explicativos, complementaridade, idéias e agência, e, portanto, enriquecer-se graças aos mesmos. / The objective of this dissertation is to develop a more parsimonious, coherent and useful concept of path dependence, both theoretically and empirically. Its fundamental insight is that with a more dynamic conceptualization, based more in negative externalities than in increasing returns, the concept of path dependence can be inherently more robust and resonate better with the literature and Historical Institutionalist studies. The concept of path dependence can also be more compatible with several theoretical developments which have arisen within Historical Institutionalism regarding questions such as institutional change, social mechanisms, complementarities, ideas, agency and, therefore, to be enriched by them.
497

A integração da geração fotovoltaica distribuída à matriz elétrica brasileira: uma análise sob a ótica institucional / The integration of the photovoltaic distributed generation on Brazilian electric matrix: an analysis from the institutional perspective

Pavanelli, João Marcos Mott 19 December 2016 (has links)
A matriz brasileira de energia elétrica foi construída historicamente como resultado da confrontação de interesses econômicos, políticos e sociais. Graças a avanços tecnológicos, o setor elétrico brasileiro passa por uma fase de possível inserção de novos modelos, como a geração distribuída de fontes energéticas alternativas, como eólica, biomassa e solar fotovoltaica. Este trabalho oferece uma análise institucional para a compreensão das possibilidades de inserção da geração distribuída fotovoltaica na rede elétrica. Essa análise institucional foi feita através de uma triangulação de técnicas, partindo de revisão bibliográfica de literatura científica, que gerou um modelo analítico para identificar e classificar os principais marcos históricos que direcionaram a estruturação da matriz energética brasileira. Os dados foram confrontados com as entrevistas em profundidade com especialistas do setor elétrico. Os resultados fundamentaram modelos que descrevem a formação histórica de instituições sob os aspectos econômicos, técnicos e normativos. Além disso, os resultados indicam um cenário favorável para investimentos em geração distribuída fotovoltaica até o final da década de 2020, mas também sugerem um possível conflito de equacionamento de custos entre os geradores distribuídos e as concessionárias de distribuição de energia elétrica / The Brazilian electric matrix was built historically as a result of the confrontation among economic, political and social interests. Given the technological advance, the Brazilians electric sector can introduce new models of electric generation, as the distributed generation from alternative energy sources as wind, biomass and photovoltaics. This study offers an institutional analysis to comprehend the perspectives of introducing distributed generation from photovoltaics on Brazilian electric network. This institutional analysis undertook a triangulation of techniques, starting from a literature review, which supported an analysis model. This model was used to identify and classify the main historic marks that constrained the choices concerning the Brazilians electric matrix composition. Historical data was confronted to in-depth interviews with specialists of the Brazilians electric sector. Results supported models which describe the historic formation of institutions under economic, technical and normative aspects. Furthermore the results indicate a favorable scenario to invest in distributed generation from photovoltaic systems in Brazil, at least until 2020, but they also forecast a possible conflict concerning the balance of some costs between the local energys distributor and the owners of distributed generation systems
498

A integração da geração fotovoltaica distribuída à matriz elétrica brasileira: uma análise sob a ótica institucional / The integration of the photovoltaic distributed generation on Brazilian electric matrix: an analysis from the institutional perspective

João Marcos Mott Pavanelli 19 December 2016 (has links)
A matriz brasileira de energia elétrica foi construída historicamente como resultado da confrontação de interesses econômicos, políticos e sociais. Graças a avanços tecnológicos, o setor elétrico brasileiro passa por uma fase de possível inserção de novos modelos, como a geração distribuída de fontes energéticas alternativas, como eólica, biomassa e solar fotovoltaica. Este trabalho oferece uma análise institucional para a compreensão das possibilidades de inserção da geração distribuída fotovoltaica na rede elétrica. Essa análise institucional foi feita através de uma triangulação de técnicas, partindo de revisão bibliográfica de literatura científica, que gerou um modelo analítico para identificar e classificar os principais marcos históricos que direcionaram a estruturação da matriz energética brasileira. Os dados foram confrontados com as entrevistas em profundidade com especialistas do setor elétrico. Os resultados fundamentaram modelos que descrevem a formação histórica de instituições sob os aspectos econômicos, técnicos e normativos. Além disso, os resultados indicam um cenário favorável para investimentos em geração distribuída fotovoltaica até o final da década de 2020, mas também sugerem um possível conflito de equacionamento de custos entre os geradores distribuídos e as concessionárias de distribuição de energia elétrica / The Brazilian electric matrix was built historically as a result of the confrontation among economic, political and social interests. Given the technological advance, the Brazilians electric sector can introduce new models of electric generation, as the distributed generation from alternative energy sources as wind, biomass and photovoltaics. This study offers an institutional analysis to comprehend the perspectives of introducing distributed generation from photovoltaics on Brazilian electric network. This institutional analysis undertook a triangulation of techniques, starting from a literature review, which supported an analysis model. This model was used to identify and classify the main historic marks that constrained the choices concerning the Brazilians electric matrix composition. Historical data was confronted to in-depth interviews with specialists of the Brazilians electric sector. Results supported models which describe the historic formation of institutions under economic, technical and normative aspects. Furthermore the results indicate a favorable scenario to invest in distributed generation from photovoltaic systems in Brazil, at least until 2020, but they also forecast a possible conflict concerning the balance of some costs between the local energys distributor and the owners of distributed generation systems
499

Target localization using RSS measurements in wireless sensor networks

Li, Zeyuan January 2018 (has links)
The subject of this thesis is the development of localization algorithms for target localization in wireless sensor networks using received signal strength (RSS) measurements or Quantized RSS (QRSS) measurements. In chapter 3 of the thesis, target localization using RSS measurements is investigated. Many existing works on RSS localization assumes that the shadowing components are uncorrelated. However, here, shadowing is assumed to be spatially correlated. It can be shown that localization accuracy can be improved with the consideration of correlation between pairs of RSS measurements. By linearizing the corresponding Maximum Likelihood (ML) objective function, a weighted least squares (WLS) algorithm is formulated to obtain the target location. An iterative technique based on Newtons method is utilized to give a solution. Numerical simulations show that the proposed algorithms achieves better performance than existing algorithms with reasonable complexity. In chapter 4, target localization with an unknown path loss model parameter is investigated. Most published work estimates location and these parameters jointly using iterative methods with a good initialization of path loss exponent (PLE). To avoid finding an initialization, a global optimization algorithm, particle swarm optimization (PSO) is employed to optimize the ML objective function. By combining PSO with a consensus algorithm, the centralized estimation problem is extended to a distributed version so that can be implemented in distributed WSN. Although suboptimal, the distributed approach is very suitable for implementation in real sensor networks, as it is scalable, robust against changing of network topology and requires only local communication. Numerical simulations show that the accuracy of centralized PSO can attain the Cramer Rao Lower Bound (CRLB). Also, as expected, there is some degradation in performance of the distributed PSO with respect to the centralized PSO. In chapter 5, a distributed gradient algorithm for RSS based target localization using only quantized data is proposed. The ML of the Quantized RSS is derived and PSO is used to provide an initial estimate for the gradient algorithm. A practical quantization threshold designer is presented for RSS data. To derive a distributed algorithm using only the quantized signal, the local estimate at each node is also quantized. The RSS measurements and the local estimate at each sensor node are quantized in different ways. By using a quantization elimination scheme, a quantized distributed gradient method is proposed. In the distributed algorithm, the quantization noise in the local estimate is gradually eliminated with each iteration. Simulations show that the performance of the centralized algorithm can reach the CRLB. The proposed distributed algorithm using a small number of bits can achieve the performance of the distributed gradient algorithm using unquantized data.
500

O ciclo da política nacional de concessão de benefícios tributários (2003-2010) / The national policy cycle of tax breaks concession (2003-2010)

Gonçalves, Maete Pedroso 28 November 2012 (has links)
Essa dissertação pretende mostrar que, na fase de formulação da política nacional de concessão de benefícios tributários, não existem obstáculos impeditivos à imposição da agenda do governo. Essa fase é antes marcada pela discricionariedade do Executivo na apresentação frequente de Medidas Provisórias que criam benefícios tributários. Além disso, o processo não é fechado à participação, pois, durante a tramitação destas proposições no Congresso Nacional, está sujeito à atuação de grupos de interesse privilegiados buscando sua parcela de benefícios distributivos. Por outro lado, existem entraves significativos colocados à fase da implementação das proposições que concedem benefícios tributários. Por ser uma política de difícil acompanhamento, sua execução está sujeita a impasses, negociações e busca de consensos entre setores da burocracia pública e destes com os órgãos de controle externo, o que impõe uma trajetória incremental à fase da implementação, e dificulta a avaliação da eficiência, eficácia e efetividade dos benefícios tributários. Além disso, a política nacional de concessão de benefícios tributários tem características de dependência de trajetória, pois, ao resolver problemas pontuais no varejo, tem se tornado a opção de ação governamental mais viável na ausência de uma reforma tributária abrangente. / This dissertation purpose to show that, at the formulation stage of national tax breaks concession policy, there are no obstacles impending the governments agenda imposition. Rather, this stage is marked by Executives discretion in the frequent presentation of Provisional Measures that create tax breaks. Also, the process is not closed to participation, because during the course of these proposals in Congress, this is liable of privileged interest groups action seeking their portion of distributive benefits. On the other hand, there are significant barriers imposed at the implementation stage of the tax breaks proposals. Because there is a policy of difficult monitoring, its execution is liable to impasses, negotiations and attempts to build consensus among sectors of the public bureaucracy and the latter with external control agencies, compelling an incremental path to the implementation stage, and hampers the evaluation of efficiency, efficacy and effectiveness of tax breaks. Furthermore, the national tax breaks concession policy has path dependence characteristics, because, to solving specific problems at retail, has become the most practicable option of governmental action in the absence of a comprehensive tax reform.

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