Large scale railway renewal planning with a multiobjective modeling approach

Conferência realizada na Filândia, Helsinquia, de 20-24 de agosto de 2018A 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.info:eu-repo/semantics/publishedVersio

Bi-objective modeling approach for repairing multiple feature infrastructure systems

A bi-objective decision aid model for planning long-term maintenance of infrastructure systems is presented, oriented to interventions on their constituent elements, with two upgrade levels possible for each element (partial/full repairs). The model aims at maximizing benefits and minimizing costs, and its novelty is taking into consideration, and combining, the system/element structure, volume discounts, and socioeconomic factors. The model is tested with field data from 229 sidewalks (systems) and compared to two simpler repair policies, of allowing only partial or full repairs. Results show that the efficiency gains are greater in the lower mid-range budget region. The proposed modeling approach is an innovative tool to optimize cost/benefits for the various repair options and analyze the respective trade-offs.info:eu-repo/semantics/publishedVersio

Multi-objective model for optimizing railway infrastructure asset renewal

Trabalho inspirado num problema real da empresa Infraestruturas de Portugal, EP.A 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.info:eu-repo/semantics/publishedVersio

Sistema de apoio à decisão espacial para análise do impacte ambiental da dispersão de poluentes atmosféricos

Neste 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.In this work a Spatial Decision Support System (SDSS) is presented, where decision makers can easily define different types of spatial problems, resorting to different object categories, pre-defined or to be defined, associating to them space dependent and non-dependent charecterisitics, and indicating forms of interference (impact) between those characteristics/properties. The spatial analysis for determining or evaluating alternative configurations for the location of different types of spatial occurrences is done interactively through the SDSS, according to sets of rules intrinsic to the various graphical elements (objects, categories, characteristics, impacts) used in the problems definitions. The representative and analytical generality of the SDSS is tested in a case study, which is specific and complex enough, relating to the application of gaussian air dispersion models to pollutants resulting from solid waste treatment. The study region of the case study is the municipality of Coimbra, Portugal. For this municipality, demographical data at the ward voting section level (official census data) were available and used. As such, a realistic study of the impact on human populations is possible.Este trabalho foi parcialmente financiado pela Fundação Portuguesa para a Ciência e Tecnologia (FCT) sob a Refa “PEst-OE/ EEI/UI308/2014”, pelo projeto Energy and Mobility for Sustainable Regions (EMSURE) - Refa CENTRO-07-0224-FEDER-002004, e enquadra-se na iniciativa Energy for Sustainability da Universidade de Coimbra

Metodologia biobjetivo para reparação de infraestruturas com múltiplos componentes

Congresso realizado em Coimbra de 24-26 de outubro de 2018.Ações de manutenção em sistemas de infraestruturas deparam-se frequentemente com o problema de decidir se uma dada ação deve ser completa ou se uma reparação parcial é suficiente para o caso em questão. A presente pesquisa apresenta um modelo biobjetivo de apoio à decisão para o planeamento da manutenção a longo prazo dos sistemas de infraestruturas, que otimiza a escolha entre reparações parciais, completas ou nenhuma ação a tomar, tomando em consideração aspetos socioeconómicos e descontos por atacado. Os objetivos considerados são a minimização do custo de reparação e maximização dos benefícios trazidos aos utilizadores. O modelo foi testado num caso de estudo 23 passeios e comparado com duas políticas de reparação mais simples, de permitir apenas reparações parciais ou completas, tendo os resultados mostrado que os ganhos de eficiência da política mista ditada pelo modelo são mais significativos na região de orçamento médio-baixo.Trabalho parcialmente financiado pela Fundação para a Ciência e Tecnologia, sob a ref.ª PEst-OE/EEI/UI308/2014, e pela iniciativa Energy for Sustainability da Universidade de Coimbra, apoiada pelo projeto Energy and Mobility for Sustainable Regions (EMSURE), sob a ref.ª CENTRO-07-0224-FEDER-002004. Os autores agradecem também à construtora “Oliveiras S.A.” e ao seu CTO Tarcísio Fogeiro pela orçamentação das reparações e discussões sobre a implementação técnica das várias soluções de reparação.info:eu-repo/semantics/publishedVersio

A multi‐objective model for publicly funded festival planning

This article proposes a multi-objective mixed-integer linear programming model to assist event managers in obtaining and evaluating non-dominated solutions to the problem of selecting a daily lineup of shows and activities for a festival – be it cultural, sports, ceremonial or any other kind. The model, which is especially adequate for designing festivals with public funding, has five objectives, relating to financial, logistical and how renowned the festival artists or acts are. It includes support for multiple days, multiple stages and differ- ent types of shows, all subject to constraints imposed by the intrinsic nature of the festival itself. The output of the model is a set of optimized daily lineups for the activities that constitute the festival, each correspond- ing to a particular compromise between the five objectives. The approach is demonstrated with a case study for a 5-day festival, for which non-dominated solutions are derived, presented and discussed. Results show that the model can provide a good variety of solutions while ensuring the persistence of the more desirable shows. The model is a novel decision support tool to assist in designing festival lineups that provide optimal audience experience, a key factor in attracting spectators, tourists and increasing comeback value.FCT DOI: 10.54499/UIDB/00308/2020info:eu-repo/semantics/publishedVersio

Planeamento multiobjetivo em projetos de renovação da ferrovia

Congresso realizado em Coimbra de 24-26 de outubro de 2018.O transporte ferroviário é visto como um modo de transporte promissor dos pontos de vista económico, energético e ambiental. No entanto, a ferrovia mundial necessita de intervenções de fundo, uma vez que a competição com o transporte rodoviário levou a falta de investimento nestas infraestruturas no século XX. Apresenta-se aqui um modelo multiobjetivo para o planeamento de renovações na rede ferroviária, atendendo a: distribuição equitativa do investimento pelos anos de projeto, minimização do custo total e minimização dos adiamentos de obras prioritárias. O modelo obedece a restrições operacionais, que visam limitar atrasos à circulação, e adequa-se a renovações que não requeiram fecho de linhas. O modelo é aplicado a um caso de estudo e os resultados mostram um considerável trade-off entre os objetivos de distribuição equitativa do investimento e adiamentos de obras prioritárias. Já o custo total só é relevante para redes muito degradadas.Trabalho parcialmente financiado pela Fundação para a Ciência e Tecnologia, sob a ref.ª PEst-OE/EEI/UI308/2014, e pela iniciativa Energy for Sustainability da Universidade de Coimbra, apoiada pelo projeto Energy and Mobility for Sustainable Regions (EMSURE), sob a ref.ª CENTRO-07-0224-FEDER- 002004.info:eu-repo/semantics/publishedVersio

THE MOLECULAR MECHANISMS OF IRON AND FERRITIN METABOLISM IN NORMAL AND NEOPLASTIC CELLS

Iron (Fe) is essential for cell growth and replication as many Fe-containing proteins catalyse key reactions involved in energy metabolism (cytochromes, mitochondrial aconitase and Fe-S proteins of the electron transport chain), respiration (hemoglobin and myoglobin) and DNA synthesis (ribonucleotide reductase). If not appropriately shielded, Fe could participate in one-electron transfer reactions that lead to the production of extremely toxic free radicals. The Fe storage protein, ferritin, is essential to protect cells against Fe-mediated oxidative stress by accommodating excess Fe into its protein shell (Xu et al., 2005). However, despite intensive research over the last few decades, many questions relating to intracellular Fe metabolism, e.g. Fe release from ferritin remain unanswered. Therefore, it is important to elucidate the molecular mechanisms of Fe trafficking in cells. At the beginning of my candidature, little was understood regarding the effect of anti-cancer agents, anthracyclines on the Fe-regulated genes, including transferrin receptor-1 (TfR1), N-myc downstream-regulated gene-1 (Ndrg1) and ferritin. Furthermore, the mechanisms of ferritin-Fe release and anthracycline-mediated ferritin-Fe accumulation are unclear. The work presented in Chapters 3 and 4 has addressed these issues. Apart from the studies examining the molecular interactions of anthracyclines with Fe, a mouse model with perturbed Fe metabolism was used and the marked alterations of protein expression in the heart of this knockout mouse model was discussed in Chapter 5. Chapter 3 Anthracyclines are effective anti-cancer agents. However, their use is limited by cardiotoxicity, an effect linked to their ability to chelate iron (Fe) and perturb Fe metabolism (Xu et al., 2005). These effects on Fe-trafficking remain poorly understood, but are important to decipher as treatment for anthracycline cardiotoxicity utilises the chelator, dexrazoxane. Incubation of cells with doxorubicin (DOX) up-regulated mRNA levels of the Fe-regulated genes, transferrin receptor-1 (TfR1) and N-myc downstream-regulated gene-1 (Ndrg1). This effect was mediated by Fe-depletion, as it was reversed by adding Fe and was prevented by saturating the anthracycline metal-binding site with Fe. However, DOX did not act like a typical chelator, as it did not induce cellular Fe mobilisation. In the presence of DOX and 59Fe-transferrin, Fe-trafficking studies demonstrated ferritin-59Fe accumulation and decreased cytosolic-59Fe incorporation. This could induce cytosolic Fe-deficiency and increase TfR1 and Ndrg1 mRNA. Up-regulation of TfR1 and Ndrg1 by DOX was independent of anthracycline-mediated radical generation and occurred via HIF-1α-independent mechanisms. Despite increased TfR1 and Ndrg1 mRNA after DOX treatment, this agent decreased TfR1 and Ndrg1 protein expression. Hence, the effects of DOX on Fe metabolism were complex due to its multiple effector mechanisms. Chapter 4 The Fe storage protein, ferritin, can accommodate up to 4500 atoms of Fe in its protein shell (Harrison and Arosio, 1996). However, the underlying mechanism of ferritin-Fe release remains unknown. Previous studies demonstrated that anti-cancer agents, anthracyclines, led to ferritin-59Fe accumulation (Kwok and Richardson, 2003). The increase in ferritin-59Fe was shown to be due to a decrease in the release of Fe from this protein. It could be speculated that DOX may impair the Fe release pathway by preventing the synthesis of essential ferritin partner proteins that induce Fe release. In this study, a native protein purification technique has been utilised to isolate ferritin-associated partners by combining ultra-centrifugation, anion-exchange chromatography, size exclusion chromatography and native gel electrophoresis. In addition to cells in culture (namely, SK-Mel-28 melanoma cells), liver taken from the mouse was used as a physiological in vivo model, as this organ is a major source of ferritin. Four potential partner proteins were identified along with ferritin, e.g. aldehyde dehydrogenase 1 family, member L1 (ALDH1L1). Future studies are required to clarify the relationship of these proteins with cellular Fe metabolism and ferritin-Fe release. Chapter 5 A frequent cause of death in Friedreich’s ataxia patients is cardiomyopathy, but the molecular alterations underlying this condition are unknown. We performed two dimensional electrophoresis to characterise the changes in protein expression of hearts using the muscle creatine kinase frataxin conditional knockout (KO) mouse. Pronounced changes in the protein expression profile were observed in 9-week-old KO mice with severe cardiomyopathy. In contrast, only a few proteins showed altered expression in asymptomatic 4-week-old KO mice. In hearts from frataxin KO mice, components of the iron-dependent complex-I and -II of the mitochondrial electron transport chain and enzymes involved in ATP homeostasis (creatine kinase, adenylate kinase) displayed decreased expression. Interestingly, the KO hearts exhibited increased expression of enzymes involved in the citric acid cycle, catabolism of branched-chain amino acids, ketone body utilisation and pyruvate decarboxylation. This constitutes evidence of metabolic compensation due to decreased expression of electron transport proteins. There was also pronounced up-regulation of proteins involved in stress protection, such as a variety of chaperones, as well as altered expression of proteins involved in cellular structure, motility and general metabolism. This is the first report of the molecular changes at the protein level which could be involved in the cardiomyopathy of the frataxin KO mouse

Anais do III Encontro de Escritores de Língua Portuguesa

Literatura e Lusofonia, colectânea dos textos apresentados ao III Encontro de Escritores de Língua Portuguesa, realizado na cidade de Natal.Câmara Municipal de Natal e Câmara Municipal de Lisboainfo:eu-repo/semantics/publishedVersio

Measuring Incineration Plants' Performance using Combined Data Envelopment Analysis, Goal Programming and Mixed Integer Linear Programming

Incineration plants produce heat and power from waste, reduce waste disposal to landfills, and discharge harmful emissions and bottom ash. The objective of the incineration plant is to maximize desirable outputs (heat and power) and minimize undesirable outputs (emissions and bottom ash). Therefore, studying the overall impact of incineration plants in a region so as to maximize the benefits and minimize the environmental impact is significant. Majority of prior works focus on plant specific decision making issues including performance analysis. This study proposes a hybrid Data Envelopment Analysis (DEA), Goal Programming (GP) and Mixed Integer Linear Programming (MILP) model to assess the performance of incineration plants, in a specific region, to enhance overall power production, consumption of waste and reduction of emissions. This model not only helps the plant operators to evaluate the effectiveness of incineration but also facilitates the policy makers to plan for overall waste management of the region through decision-making on adding and closing plants on the basis of their efficiency. Majority of prior studies on incineration plants emphasize on how to improve their performance on heat and power production and neglect the waste management aspects. Additionally, optimizing benefits and minimizing negative outputs through fixing targets in order to make decision on shutting down the suboptimal plants has not been modeled in prior research. This research combines both the aspects and addresses the overall performance enhancement of incineration plants within a region from both policy makers and plant operators’ perspectives. The proposed combined DEA, GP and MILP model enables to optimize incineration plants performance within a region by deriving efficiency of each plant and identifying plants to close down on the basis of their performance. The proposed model has been applied to a group of 22 incineration plants in the UK using secondary data in order to demonstrate the effectiveness of the model.