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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.
181

Avaliação de indicadores de desempenho na análise de importância de segmentos de uma rede viária

Dalosto, Francisco Marchet January 2018 (has links)
A identificação dos segmentos críticos da rede viária é um conhecimento básico que todo planejador de transportes deve ter sobre a rede viária. É inevitável a ocorrência de incidentes e eventos de redução da capacidade nos elementos da rede. O efeito de acidentes e obstruções em segmentos críticos da rede ocasionam impactos que prejudicam o desempenho da rede. Este estudo foi desenvolvido com o apoio do modelo de alocação de tráfego do software VISUM (versão 2015) e propõe um método para determinar a importância de cada segmento da rede viária, a identificação de segmentos críticos da rede e a avaliação de sua obstrução de forma estática e dinâmica. Para isso, são utilizados diversos indicadores de desempenho da rede viária. O método foi aplicado na região do Litoral Norte do Rio Grande do Sul, utilizando os dados de tráfego fornecidos pela CONCEPA TRIUNFO, DAER e DNIT. A determinação da importância de cada segmento decorreu da avaliação do impacto na rede causado pela obstrução do próprio segmento. Através do método proposto neste estudo foi possível identificar o segmento crítico da rede viária estudada e, de forma qualitativa, verificar a extensão da obstrução desse segmento nas análises estática e dinâmica Verificou-se que o indicador diferença do total de tempo despendido na rede é o indicador que mais apresenta crescimento com o incremento da demanda, não apresenta alterações de priorização dos segmentos frente a variações de intensidade e sentido da demanda. Os resultados deste estudo mostraram que o segmento crítico da rede pertence a BR-101 entre os municípios de Osório e Terra de Areia. O método de hierarquização proposto independe do sentido e da intensidade da demanda, e está sujeito a mais de uma métrica para avaliar o segmento crítico. Estes resultados podem subsidiar o planejamento de transportes, identificando trechos críticos da rede viária que necessitam de mais atenção dos gestores e apontando medidas de operação no caso de eventos disruptivos nos trechos críticos. / Identifying the most important link of the network is essential knowledge that the transport planners should have over the network. Incidents and events of capacity reduction in network elements are inevitable. The effect of accidents and obstructions on critical network links causes impacts that hamper network performance. This study was developed with support of VISUM (version 2015) traffic assignment model software with proposes a method to determinate each network link importance level, to identify the critical link and to measure the critical link blockage impact on network. For this, several road network performance indicators are used. The method was applied in the North Coast region of Rio Grande do Sul, using traffic data provided by CONCEPA TRIUNFO, DAER and DNIT. The link level importance in define from the own link impact due its obstruction. The proposed method identified the most critical link of the studied network and verified the qualitative impact of its obstruction extent in the static and dynamic assignment analyses It was verified that the measure total spent time difference in the network is the most sensible measure that growth with a demand increase, this measure does not present changes the link importance rank against variations of intensity and direction of demand flow changes. The results of this study show that the critical link of the network belongs to the BR-101 highway between the municipalities of Osório and Terra de Areia. The proposed hierarchical method developed with several metrics measures fond the critical link in an independent demand direction and intensity analysis. The findings may support transport planners to identify the most critical arc of a network. To better implement resources of road management and repairs. Also identify where the operation measures may be implanted in face a disruptive event on a critical link.
182

An Improved Framework for Dynamic Origin-Destination (O-D) Matrix Estimation

Chi, Hongbo 09 November 2010 (has links)
This dissertation aims to improve the performance of existing assignment-based dynamic origin-destination (O-D) matrix estimation models to successfully apply Intelligent Transportation Systems (ITS) strategies for the purposes of traffic congestion relief and dynamic traffic assignment (DTA) in transportation network modeling. The methodology framework has two advantages over the existing assignment-based dynamic O-D matrix estimation models. First, it combines an initial O-D estimation model into the estimation process to provide a high confidence level of initial input for the dynamic O-D estimation model, which has the potential to improve the final estimation results and reduce the associated computation time. Second, the proposed methodology framework can automatically convert traffic volume deviation to traffic density deviation in the objective function under congested traffic conditions. Traffic density is a better indicator for traffic demand than traffic volume under congested traffic condition, thus the conversion can contribute to improving the estimation performance. The proposed method indicates a better performance than a typical assignment-based estimation model (Zhou et al., 2003) in several case studies. In the case study for I-95 in Miami-Dade County, Florida, the proposed method produces a good result in seven iterations, with a root mean square percentage error (RMSPE) of 0.010 for traffic volume and a RMSPE of 0.283 for speed. In contrast, Zhou’s model requires 50 iterations to obtain a RMSPE of 0.023 for volume and a RMSPE of 0.285 for speed. In the case study for Jacksonville, Florida, the proposed method reaches a convergent solution in 16 iterations with a RMSPE of 0.045 for volume and a RMSPE of 0.110 for speed, while Zhou’s model needs 10 iterations to obtain the best solution, with a RMSPE of 0.168 for volume and a RMSPE of 0.179 for speed. The successful application of the proposed methodology framework to real road networks demonstrates its ability to provide results both with satisfactory accuracy and within a reasonable time, thus establishing its potential usefulness to support dynamic traffic assignment modeling, ITS systems, and other strategies.
183

Avaliação de indicadores de desempenho na análise de importância de segmentos de uma rede viária

Dalosto, Francisco Marchet January 2018 (has links)
A identificação dos segmentos críticos da rede viária é um conhecimento básico que todo planejador de transportes deve ter sobre a rede viária. É inevitável a ocorrência de incidentes e eventos de redução da capacidade nos elementos da rede. O efeito de acidentes e obstruções em segmentos críticos da rede ocasionam impactos que prejudicam o desempenho da rede. Este estudo foi desenvolvido com o apoio do modelo de alocação de tráfego do software VISUM (versão 2015) e propõe um método para determinar a importância de cada segmento da rede viária, a identificação de segmentos críticos da rede e a avaliação de sua obstrução de forma estática e dinâmica. Para isso, são utilizados diversos indicadores de desempenho da rede viária. O método foi aplicado na região do Litoral Norte do Rio Grande do Sul, utilizando os dados de tráfego fornecidos pela CONCEPA TRIUNFO, DAER e DNIT. A determinação da importância de cada segmento decorreu da avaliação do impacto na rede causado pela obstrução do próprio segmento. Através do método proposto neste estudo foi possível identificar o segmento crítico da rede viária estudada e, de forma qualitativa, verificar a extensão da obstrução desse segmento nas análises estática e dinâmica Verificou-se que o indicador diferença do total de tempo despendido na rede é o indicador que mais apresenta crescimento com o incremento da demanda, não apresenta alterações de priorização dos segmentos frente a variações de intensidade e sentido da demanda. Os resultados deste estudo mostraram que o segmento crítico da rede pertence a BR-101 entre os municípios de Osório e Terra de Areia. O método de hierarquização proposto independe do sentido e da intensidade da demanda, e está sujeito a mais de uma métrica para avaliar o segmento crítico. Estes resultados podem subsidiar o planejamento de transportes, identificando trechos críticos da rede viária que necessitam de mais atenção dos gestores e apontando medidas de operação no caso de eventos disruptivos nos trechos críticos. / Identifying the most important link of the network is essential knowledge that the transport planners should have over the network. Incidents and events of capacity reduction in network elements are inevitable. The effect of accidents and obstructions on critical network links causes impacts that hamper network performance. This study was developed with support of VISUM (version 2015) traffic assignment model software with proposes a method to determinate each network link importance level, to identify the critical link and to measure the critical link blockage impact on network. For this, several road network performance indicators are used. The method was applied in the North Coast region of Rio Grande do Sul, using traffic data provided by CONCEPA TRIUNFO, DAER and DNIT. The link level importance in define from the own link impact due its obstruction. The proposed method identified the most critical link of the studied network and verified the qualitative impact of its obstruction extent in the static and dynamic assignment analyses It was verified that the measure total spent time difference in the network is the most sensible measure that growth with a demand increase, this measure does not present changes the link importance rank against variations of intensity and direction of demand flow changes. The results of this study show that the critical link of the network belongs to the BR-101 highway between the municipalities of Osório and Terra de Areia. The proposed hierarchical method developed with several metrics measures fond the critical link in an independent demand direction and intensity analysis. The findings may support transport planners to identify the most critical arc of a network. To better implement resources of road management and repairs. Also identify where the operation measures may be implanted in face a disruptive event on a critical link.
184

Continuous Integration Pipelines to Assess Programming Assignments : Test Like a Professional

Strand, Anton January 2020 (has links)
Examiners of programming assignments in higher education and people in the software industry both need to test and review code. However, the assessing techniques used are often quite different. The IT industry often uses agile work methods like continuous integration and automated tests, while examiners either do manual assessments or rely on code grading tools. The students will most likely become developers and work using agile processes. Therefore, there are possible benefits of universities trying to imitate the work processes of the software industry. The purpose of this study was to develop a workflow for programming assignments inspired by continuous integration, Scrum, and GitLab flow. The workflow was developed based on the requirements of Linnaeus University and tested on one of their programming assignments. It showed that a simplified agile work process is suitable for programming assignments since the demonstration fulfilled all of the predefined requirements. However, examiners might miss some of the workflow’s benefits if the programming assignment can not be tested automatically since it will require more manual work while grading.
185

Gated Single Assignment Form Partnered with Value-Based Statistical Fault Localization for Numerical Java Programs

Traben, Oliver 26 May 2023 (has links)
No description available.
186

Towards Combinatorial Assignment in a Euclidean Environmentwith many Agents : applied in StarCraft II / Mot kombinatoriskt uppdrags tilldelning i en euklidisk miljö medmånga agenter

Bergström, Edvin January 2022 (has links)
This thesis investigates coordinating units through simultaneous coalition structuregeneration and task assignment in a complex Euclidean environment. The environmentused is StarCraft II, and the problem modeled and solved in the game is the distribution ofcombat units over the game’s map. The map was split into regions, and every region wasmodeled as a task to which the combat units were assigned.In a number of experiments, we compare the performance of our approach with thegame’s built-in bots. Against most of the non cheating options, our agent wins 20% of thegames played on a large map, against the Hard built-in bot. On a smaller and simpler mapit wins 22% of games played against the hardest non-cheating difficulty.One of the main limitations of the method used to solve the assignment was the utility function. Which should describe the quality of a coalition and the task assignment.However, as the utility function described the state’s utility better, the win rate increased.Therefore the result indicates that the simultaneous coalition structure generation and taskassignment work for unit distribution in a complex environment like StarCraft II if a sufficient utility function is provided.
187

A model for the economic analysis of road projects in an urban network with interrelated incremental traffic assignment method

Lloyd, Evan Robert January 2005 (has links)
[Truncated abstract] In an urban network, any change to the capacity of a road or an intersection will generally result in some traffic changing its route. In addition the presence of intersections creates the need for frequent stops. These stops increase the fuel consumption by anywhere between thirty to fifty percent as evidenced by published standardised vehicle fuel consumption figures for urban and for country driving. Other components of vehicle operating costs such as tyre and brake wear and time costs will also be increased by varying amounts. Yet almost all methods in use for economic evaluation of urban road projects use open road vehicle operating costs (sometimes factored to represent an average allowance for stopping at intersections) for one year or sometimes two years in the analysis period and then make assumptions about how the year by year road user benefits may change throughout the period in order to complete the analysis. This thesis will describe a system for estimating road user costs in an urban network that calculates intersection effects separately and then adds these effects to the travel costs of moving between intersections. Daily traffic estimates are used with a distribution of the flow rate throughout the twenty-four hours giving variable speed of travel according to the level of congestion at different times of the day. For each link, estimates of traffic flow at two points in time are used to estimate the year-by-year traffic flow throughout the analysis period by linear interpolation or extrapolation. The annual road user costs are then calculated from these estimates. Annual road user benefits are obtained by subtracting the annual road user costs for a modified network from the annual road user costs for an unmodified network. The change in the road network maintenance costs are estimated by applying an annual per lane maintenance cost to the change in lane-kilometres of road in the two networks. The Benefit Cost Ratio is calculated for three discount rates. An estimate of the likely range of error in the Benefit Cost Ratio is also calculated
188

[en] CHANNEL ALLOCATION COMPARATIVE ANALYSIS FOR TDMA TECHNOLOGY / [pt] ALOCAÇÃO DE CANAIS ANÁLISE COMPARATIVA PARA TECNOLOGIA TDMA

LEONARDO CRUZ MELLO 25 October 2002 (has links)
[pt] Os esquemas de alocação fixa de canais - FCA - conferem aos Sistemas de Comunicação Móveis Celulares estabilidade com o custo da necessidade de um pré-planejamento de freqüências, trazendo como conseqüência a baixa tolerância à variabilidade de tráfego. Algoritmos de alocação dinâmica de canais - DCA - tem sido propostos por diversos autores com o intuito de minimizar estes problemas, permitindo ao sistema flexibilidade no momento da escolha do canal candidato para servir a uma ligação. Esquemas de alocação híbrida de canais - HCA, combinam as técnicas de alocação fixa com alocação dinâmica de canais, conferindo ao mesmo tempo estabilidade e flexibilidade ao sistema.Este trabalho compara os algoritmos FCA, DCA e HCA sobre um mesmo cenário de simulação, permitindo analisar o desempenho dos mesmos. O esquema FCA utilizado é o mais simples, onde o primeiro canal com o nível aceitável de relação sinal interferência é escolhido para ser alocado. O esquema DCA utiliza a técnica de Segregação de Canais - CS, permitindo ao sistema maior flexibilidade no momento da escolha do canal candidato, devido a não existência do pré-planejamento de freqüências. O terceiro algoritmo, HCA, combina os dois esquemas anteriores. Ao final, será analisado o impacto de se priorizar o procedimento de handoff utilizando-se a técnica conhecida como Canais de Guarda. / [en] Fixed channel assignment -FCA- brings to the Cellular Communication Systems stability at the cost of the use of frequency planning, leading to low tolerance to traffic variability. Dynamic channel assignment -DCA- algorithms have been proposed by several authors in order to minimize these problems,incorporating flexibility to the system with respect to channel selection. Hybrid channel assignment - HCA- combines the techniques of fixed and dynamic channel assignment, giving to the system stability and flexibility at the same time. This work compares the FCA, DCA and HCA algorithms on the same simulation scenario, allowing a complete analysis of these approaches. The FCA used is the simplest. In this algorithm, the first channel with an acceptable level of signal to interference ratio is chosen to be allocated. The DCA uses the technique of Channel Segregation -CS-, a distributed self-learning algorithm that is shown to yield very good performance. The third algorithm,HCA, combine the two previous techniques. At the end, the impact of prioritizing the procedure of handoff will be analyzed, using the technique known as Guard Channel.
189

A dual approximation framework for dynamic network analysis: congestion pricing, traffic assignment calibration and network design problem

Lin, Dung-Ying 10 November 2009 (has links)
Dynamic Traffic Assignment (DTA) is gaining wider acceptance among agencies and practitioners because it serves as a more realistic representation of real-world traffic phenomena than static traffic assignment. Many metropolitan planning organizations and transportation departments are beginning to utilize DTA to predict traffic flows within their networks when conducting traffic analysis or evaluating management measures. To analyze DTA-based optimization applications, it is critical to obtain the dual (or gradient) information as dual information can typically be employed as a search direction in algorithmic design. However, very limited number of approaches can be used to estimate network-wide dual information while maintaining the potential to scale. This dissertation investigates the theoretical/practical aspects of DTA-based dual approximation techniques and explores DTA applications in the context of various transportation models, such as transportation network design, off-line DTA capacity calibration and dynamic congestion pricing. Each of the later entities is formulated as bi-level programs. Transportation Network Design Problem (NDP) aims to determine the optimal network expansion policy under a given budget constraint. NDP is bi-level by nature and can be considered a static case of a Stackelberg game, in which transportation planners (leaders) attempt to optimize the overall transportation system while road users (followers) attempt to achieve their own maximal benefit. The first part of this dissertation attempts to study NDP by combining a decomposition-based algorithmic structure with dual variable approximation techniques derived from linear programming theory. One of the critical elements in considering any real-time traffic management strategy requires assessing network traffic dynamics. Traffic is inherently dynamic, since it features congestion patterns that evolve over time and queues that form and dissipate over a planning horizon. It is therefore imperative to calibrate the DTA model such that it can accurately reproduce field observations and avoid erroneous flow predictions when evaluating traffic management strategies. Satisfactory calibration of the DTA model is an onerous task due to the large number of variables that can be modified and the intensive computational resources required. In this dissertation, the off-line DTA capacity calibration problem is studied in an attempt to devise a systematic approach for effective model calibration. Congestion pricing has increasingly been seen as a powerful tool for both managing congestion and generating revenue for infrastructure maintenance and sustainable development. By carefully levying tolls on roadways, a more efficient and optimal network flow pattern can be generated. Furthermore, congestion pricing acts as an effective travel demand management strategy that reduces peak period vehicle trips by encouraging people to shift to more efficient modes such as transit. Recently, with the increase in the number of highway Build-Operate-Transfer (B-O-T) projects, tolling has been interpreted as an effective way to generate revenue to offset the construction and maintenance costs of infrastructure. To maximize the benefits of congestion pricing, a careful analysis based on dynamic traffic conditions has to be conducted before determining tolls, since sub-optimal tolls can significantly worsen the system performance. Combining a network-wide time-varying toll analysis together with an efficient solution-building approach will be one of the main contributions of this dissertation. The problems mentioned above are typically framed as bi-level programs, which pose considerable challenges in theory and as well as in application. Due to the non-convex solution space and inherent NP-complete complexity, a majority of recent research efforts have focused on tackling bi-level programs using meta-heuristics. These approaches allow for the efficient exploration of complex solution spaces and the identification of potential global optima. Accordingly, this dissertation also attempts to present and compare several meta-heuristics through extensive numerical experiments to determine the most effective and efficient meta-heuristic, as a means of better investigating realistic network scenarios. / text
190

Cessão da posição contratual / Assignment of contractual position.

Nascimento, Sérgio Santos do 13 March 2015 (has links)
Esta dissertação trata do instituto da cessão da posição contratual. Embora a assunção de dívida seja hoje aceita pelo ordenamento pátrio, tal como a cessão de crédito, a cessão da posição contratual não foi disciplinada pelo Código Civil. Conquanto ninguém duvide da existência do instituto como negócio jurídico inominado, sua ausência de disciplina suscita debate sobre as regras a ele aplicáveis. Inicialmente, é feita uma breve contextualização histórica para demonstrar as dificuldades que o instituto enfrentou para ser aceito pela doutrina e legislações, tendo surgido inicialmente por conta das necessidades da vida prática. Porque frequentes as tentativas de aproximar a cessão da posição contratual com outros institutos, também é demonstrada a singularidade dessa figura jurídica e as suas diferenças com outras semelhantes (novação, sub-rogação, adesão ao contrato, subcontrato e contrato com pessoa a declarar). O conceito, terminologia e natureza jurídica do instituto são exaustivamente abordados em capítulo próprio. No capítulo seguinte e central da dissertação, são tratados os desdobramentos do instituto (possibilidade de utilização da cessão da posição contratual nos contratos bilaterais e unilaterais, bem como nos contratos com prestações exauridas; impossibilidade da cessão parcial da posição contratual; valoração do consentimento do cedido e sua classificação; garantia da existência e validade do contrato pelo cedente e sua responsabilidade pelo cumprimento do contrato; manutenção das garantias prestadas pelo cedente e por terceiros após a cessão da posição contratual; transmissão dos direitos potestativos, deveres laterais e cláusula arbitral; possibilidade de revisão das cláusulas contratuais pelo cessionário; manutenção da forma de interpretação do contrato pelo novo contraente; cessão da posição contratual nos contratos de adesão e nos contratos personalíssimos; casos de intransmissibilidade da cessão da posição contratual; e alguns aspectos processuais do instituto). É tratada, por fim, da necessidade de o Código Civil disciplinar expressamente o instituto, não por mero capricho ou preciosismo, mas porque a recorrente utilização do instituto pela sociedade justifica a existência de regras claras sobre o tema, trazendo maior segurança jurídica e estabilidade social. / This dissertation deals with the doctrine of assignment of contractual position. Although assumption of debt and assignment of credit are accepted in Brazilian law, assignment of contractual position is not covered by the Civil Code. Although no one questions the existence of the doctrine of assignment of contractual position as a transaction without a specific provision, the absence of statutory provision brings into discussion the rules that apply to the doctrine. Initially, one provides a historical background to demonstrate the difficulties the doctrine has overcome in order to be accepted by scholars and in the legislations, having first appeared due to the necessities of everyday life. Because the attempt to bring assignment of contract closer to other doctrines is recurrent, one also demonstrates the singularity of this legal figure and its differences from others (novation, subrogation, adhesion to a contract, a subcontract and a contract with a person to be declared). The concept, the terminology and the legal nature of the doctrine are exhaustively approached in a specific chapter. In the following chapter, central to this dissertation, one deals with the developments of the doctrine (possibility of applying assignment of contract for bilateral and unilateral contracts, as well as for contracts with their considerations already exhausted; impossibility of partial assignment of contractual position; appraisal of the consent of the obligor and its classification; guarantee of the existence and validity of the contract by the assignor and its responsibility for performance of the contract; maintenance of the guarantees offered by the assignor and by third parties after assignment of the contract; assignment of potestative rights, lateral duties, and arbitration clause; possibility of review of contractual clauses by the assignee; maintenance of a form of contractual interpretation by the new party; assignment of contract for adhesion and personal contracts; cases of impossibility of assignment of contract; and other procedural aspects of the doctrine). Finally, one deals with the need for the Civil Code to provide for the doctrine expressly, not in a superfluous or purposeless way, but because the recurring application of the doctrine by the society justifies the existence of clear rules about the subject, bringing greater legal safety and social stability.

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