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- Sistema de apoio à decisão espacial para análise do impacte ambiental da dispersão de poluentes atmosféricosPublication . Almeida, Luís Alçada; Rodrigues, João Coutinho; Sousa, NunoNeste artigo é apresentado um Sistema de Apoio à Decisão Espacial (SADE) onde os decisores podem facilmente definir diferentes tipos de problemas espaciais recorrendo a diferentes categorias de objetos, pré-definidas ou a definir, associando- lhes características com ou sem dependência espacial, e indicando formas de interferência (impactos) entre essas caracte- rísticas/propriedades. A análise espacial para determinação ou avaliação de configurações alternativas para a localização de diferentes tipos de ocorrências espaciais será feita através da utilização interativa do SADE de acordo com conjuntos de regras intrínsecas aos vários elementos gráficos (objetos, categorias, características, impactos) utilizados na definição dos problemas. O teste à generalidade representativa e analítica do SADE proposto é efectuado recorrendo a um problema concreto, suficientemente específico e complexo, relativo à aplicação de modelos gaussianos para o estudo da dispersão atmosférica de eventuais poluentes resultantes do tratamento de resíduos sólidos. A região em estudo está limitada, neste exemplo, ao município de Coimbra, Portugal. Para este município estão acessíveis, e são utilizados, os dados demográficos ao nível da secção de voto (censos oficiais) e, como tal, é possível a realização de um estudo realístico do impacto com populações humanas.
- Física : movimento de projétilPublication . Sousa, Nuno; Silva, Fátima Ferreira da; Silva, Helder Matta e
- Sidewalk infrastructure assessment using a multicriteria methodology for maintenance planningPublication . Sousa, Nuno; Rodrigues, João Coutinho; Jesus, Eduardo NatividadeSidewalks constitute the main guideway for the walking mode of transport and serve as a fundamental infrastructure for personal travel including commuting. This is because practically every motorized trip is preceded or concluded by nonmotorized travel. The assessment of sidewalk performance, in the sense of its suitability for walking, involves consideration of multiple aspects, whose precise treatment requires in turn the use of multicriteria methods to support decisions. This article proposes a multicriteria methodology for this purpose, thus setting the stage for a subsequent agency decision regarding maintenance strategy development. The methodology is based on a set of infrastructure attributes, directly intervenable by these authorities, and uses the ELECTRE TRI method to assign sidewalks under study to performance classes. It is practical to use and can be applied to any city, at any scale. The approach is thoroughly discussed, and demonstrated for a case study comprising several sidewalks in the city of Coimbra, Portugal. The results indicate that a considerable fraction of these sidewalks are in mediocre condition, and the multicriteria classifying methodology readily suggested intervention strategies, effectively aiding in the decision making.
- Multi-objective model for optimizing railway infrastructure asset renewalPublication . Sousa, Nuno; Almeida, Luís Alçada; Rodrigues, João CoutinhoA multi-objective model for managing railway infrastructure asset renewal is presented. The model aims to optimize three objectives, while respecting operational constraints: levelling investment throughout multiple years, minimizing total cost and minimizing work start postponements. Its output is an optimized intervention schedule. The model is based on a case study from a Portuguese infrastructure management company, which specified the objectives and constraints, and reflects management practice on railway infrastructure. The results show that investment levelling greatly influences the other objectives and that total cost fluctuations may range from insignificant to important, depending on the condition of the infrastructure. The results structure is argued to be general and suggests a practical methodology for analysing trade-offs and selecting a solution for implementation.
- Large scale railway renewal planning with a multiobjective modeling approachPublication . Sousa, Nuno; Almeida, Luís Alçada; Rodrigues, João CoutinhoA multiobjective modeling approach for managing large scale railway infrastructure asset renewal is presented. An optimized intervention project schedule is obtained considering operational constraints in a three objectives model: evenly spreading investment throughout multiple years, minimizing total cost, minimizing work start postponements on higher priority railway sections. The MILP model was based on a real world case study; the objectives and constraints specified by an infrastructure management company. Results show that investment spreading greatly influences the other objectives and that total cost fluctuations depend on the overall condition of the railway infrastructure. The model can produce exact efficient solutions in reasonable time, even for very large-sized instances (a test network of similar size to the USA railway network, the largest in the world). The modeling approach is therefore a very useful, practical methodology, for generating optimized solutions and analyzing trade-offs among objectives, easing the task of ultimately selecting a solution and produce the works schedule for field implementation.
- Design of evacuation plans for densely urbanised city centresPublication . Rodrigues, João Coutinho; Sousa, Nuno; Jesus, Eduardo NatividadeThe high population density and tightly packed nature of some city centres make emergency planning for these urban spaces especially important, given the potential for human loss in case of disaster. Historic and recent events have made emergency service planners particularly conscious of the need for preparing evacuation plans in advance. This paper discusses a methodological approach for assisting decision-makers in designing urban evacuation plans. The approach aims at quickly and safely moving the population away from the danger zone into shelters. The plans include determining the number and location of rescue facilities, as well as the paths that people should take from their building to their assigned shelter in case of an occurrence requiring evacuation. The approach is thus of the location–allocation–routing type, through the existing streets network, and takes into account the trade-offs among different aspects of evacuation actions that inevitably come up during the planning stage. All the steps of the procedure are discussed and systematised, along with computational and practical implementation issues, in the context of a case study – the design of evacuation plans for the historical centre of an old European city.
- Algumas técnicas SIG úteis à obtenção de áreas de serviço de conjuntos de pontosPublication . Tralhao, Lino; Rodrigues, João Coutinho; Sousa, NunoEm estudos de acessibilidade, e não só, são muito úteis um tipo de estruturas que se podem obter a partir de uma rede, eventualmente multi-modal e parametrizável: as chamadas “áreas de serviço”, as quais são constituídas por polígonos, cada qual correspondente a uma zona situada entre um certo intervalo de custo, relativamente a uma certa “feature” (ponto, multiponto, etc.). Pretende-se neste estudo obter, a partir de áreas de serviço relativas a um universo de features, áreas de serviço relativas a subconjuntos dessas features. Estas técnicas envolvem manipulações relativamente complexas de polígonos e podem ser generalizadas para conjuntos de conjuntos e assim sucessivamente. Convém notar que nem sempre se dispõe da rede, podendo dispor-se das referidas estruturas; eventualmente, no caso de áreas de serviço, sob a forma de imagens (raster) a serem convertidas para formato vectorial.
- An energy-based pedestrian accessibility indicatorPublication . Sousa, Nuno; Moreira, Florbela; Rodrigues, João CoutinhoThis article presents an approach to pedestrian accessibility based on human effort rather than distance. By measuring effort as the muscular energy required to traverse network arcs with slopes, it is possible to derive an accessibility indicator that takes relief into account. A case study in the city of Coimbra, Portugal, shows that while relief does have a considerable impact on the accessibility thus measured, that impact is global and not local. When accessibility to all types of opportunities are considered, the influence of relief ultimately dilutes due to the geographical scattering of those opportunities.
- Física : conversão de unidades : 1º exemploPublication . Sousa, Nuno; Silva, Fátima Ferreira da; Silva, Helder Matta e
- Física : dinâmica : 2º exemploPublication . Sousa, Nuno; Silva, Fátima Ferreira da; Firmino, Joaquim