Méthode de génération de colonnes pour les problèmes de conception de réseaux avec coûts d’ajout de capacité

Les problèmes de conception de réseaux ont reçu un intérêt particulier et ont été largement étudiés de par leurs nombreuses applications dans différents domaines, tels que les transports et les télécommunications. Nous nous intéressons dans ce mémoire au problème de conception de réseaux avec coûts d’ajout de capacité. Il s’agit d’installer un ensemble d’équipements sur un réseau en vue de satisfaire la demande, tout en respectant les contraintes de capacité, chaque arc pouvant admettre plusieurs équipements. L’objectif est de minimiser les coûts variables de transport des produits et les coûts fixes d’installation ou d’augmentation de capacité des équipements. La méthode que nous envisageons pour résoudre ce problème est basée sur les techniques utilisées en programmation linéaire en nombres entiers, notamment celles de génération de colonnes et de coupes. Ces méthodes sont introduites dans un algorithme général de branch-and-bound basé sur la relaxation linéaire. Nous avons testé notre méthode sur quatre groupes d’instances de tailles différentes, et nous l’avons comparée à CPLEX, qui constitue un des meilleurs solveurs permettant de résoudre des problèmes d’optimisation, ainsi qu’à une méthode existante dans la littérature combinant des méthodes exactes et heuristiques. Notre méthode a été plus performante que ces deux méthodes, notamment pour les instances de très grandes tailles.

Dynamic Facility Location with Modular Capacities : Models, Algorithms and Applications in Forestry

Les décisions de localisation sont souvent soumises à des aspects dynamiques comme des changements dans la demande des clients. Pour y répondre, la solution consiste à considérer une flexibilité accrue concernant l’emplacement et la capacité des installations. Même lorsque la demande est prévisible, trouver le planning optimal pour le déploiement et l'ajustement dynamique des capacités reste un défi. Dans cette thèse, nous nous concentrons sur des problèmes de localisation avec périodes multiples, et permettant l'ajustement dynamique des capacités, en particulier ceux avec des structures de coûts complexes. Nous étudions ces problèmes sous différents points de vue de recherche opérationnelle, en présentant et en comparant plusieurs modèles de programmation linéaire en nombres entiers (PLNE), l'évaluation de leur utilisation dans la pratique et en développant des algorithmes de résolution efficaces. Cette thèse est divisée en quatre parties. Tout d’abord, nous présentons le contexte industriel à l’origine de nos travaux: une compagnie forestière qui a besoin de localiser des campements pour accueillir les travailleurs forestiers. Nous présentons un modèle PLNE permettant la construction de nouveaux campements, l’extension, le déplacement et la fermeture temporaire partielle des campements existants. Ce modèle utilise des contraintes de capacité particulières, ainsi qu’une structure de coût à économie d’échelle sur plusieurs niveaux. L'utilité du modèle est évaluée par deux études de cas. La deuxième partie introduit le problème dynamique de localisation avec des capacités modulaires généralisées. Le modèle généralise plusieurs problèmes dynamiques de localisation et fournit de meilleures bornes de la relaxation linéaire que leurs formulations spécialisées. Le modèle peut résoudre des problèmes de localisation où les coûts pour les changements de capacité sont définis pour toutes les paires de niveaux de capacité, comme c'est le cas dans le problème industriel mentionnée ci-dessus. Il est appliqué à trois cas particuliers: l'expansion et la réduction des capacités, la fermeture temporaire des installations, et la combinaison des deux. Nous démontrons des relations de dominance entre notre formulation et les modèles existants pour les cas particuliers. Des expériences de calcul sur un grand nombre d’instances générées aléatoirement jusqu’à 100 installations et 1000 clients, montrent que notre modèle peut obtenir des solutions optimales plus rapidement que les formulations spécialisées existantes. Compte tenu de la complexité des modèles précédents pour les grandes instances, la troisième partie de la thèse propose des heuristiques lagrangiennes. Basées sur les méthodes du sous-gradient et des faisceaux, elles trouvent des solutions de bonne qualité même pour les instances de grande taille comportant jusqu’à 250 installations et 1000 clients. Nous améliorons ensuite la qualité de la solution obtenue en résolvent un modèle PLNE restreint qui tire parti des informations recueillies lors de la résolution du dual lagrangien. Les résultats des calculs montrent que les heuristiques donnent rapidement des solutions de bonne qualité, même pour les instances où les solveurs génériques ne trouvent pas de solutions réalisables. Finalement, nous adaptons les heuristiques précédentes pour résoudre le problème industriel. Deux relaxations différentes sont proposées et comparées. Des extensions des concepts précédents sont présentées afin d'assurer une résolution fiable en un temps raisonnable.

Modeling growth strategy in a biotechnology startup firm

The top managers of a biotechnology startup firm agreed to participate in a system dynamics modeling project to help them think about the firm's growth strategy. The article describes how the model was created and used to stimulate debate and discussion about growth management. The paper highlights several novel features about the process used for capturing management team knowledge. A heavy emphasis was placed on mapping the operating structure of the factory and distribution channels. Qualitative modeling methods (structural diagrams, descriptive variable names, and friendly algebra) were used to capture the management team's descriptions of the business. Simulation scenarios were crafted to stimulate debate about strategic issues such as capacity allocation, capacity expansion, customer recruitment, customer retention, and market growth, and to engage the management team in using the computer to design strategic scenarios. The article concludes with comments on the impact of the project.

Política de transferência de renda e desenvolvimento local: o programa Bolsa família no município de Pedra Grande/RN

The Family Scolarship Program while public politics of intersectorial form developed by Social Development Department and Famine Combat having with partner the Education Department and Health Department inaugurate in the country a new integrity way of the public politics, reinforcing a precept of 2004 Social Protection National Politics (PNAS 2004) that places the social protection while allied to the social and human development. The research INCOME TRANSFER AND LOCAL DEVELOPMENT: the family scolarship program in Pedra Grande-RN municipally had as aim to avaluate the permanent Family Scolarship Program as a possible element in local development of Pedra Grande-RN municipally understood as capacity expansion and improvement of life quality from its users. For this means we elaborate specifically the families` socio-economical profile; we avaluate the program repercussion in these families` lives; we analyse in which proportion occurred the capacity expansion and improvement of life quality of the users. The methodologic process was constituted by: literarture review about Income Transfer, Social Vulnerability, Development and Public Politics Avaluation to the criation of a theoric picture analysis. The documental research joined to the Social Development Department and Famine Combat of Pedra Grande Municipally Hall to obtain of the aims, program goals, and the profile of users. And finally, carrying out the interviews with the managers and experts of the Municipally Program and focal groups with the users to avaluate the permanent of the Program starting by the points of view of those ones. It was verified that the program expand the capacity (food, consumer goods and services, bank services access and wages) and improvement in life quality of the users. Nevertheless, there are deficiencies in coming with conditionality and from the use of resources the by families users

Geração de energia fotovoltaica para cargas pontuais em residências

This work, based in a patent request at INPI, protocol no. 020110035974, presents a system development using solar panels to supply the electricity demand required by punctual loads, without a storage unit or utility grid synchronism, through a control circuit that allows parallel operation with the power grid during low sunlight incidence periods. A study about solar panel construction and topologies for Power generation was done, in a atempt to evalute impacts in project. This development was modular, providing the system the possibility of power capacity expansion and load diversity as well, in an attempt to reduce the total energy requirements from the residential sector drained from the power grid along the day

Remodelagem de uma usina sucroalcooleira para incremento da cogeração de energia com aproveitamento do palhiço

Pós-graduação em Engenharia Mecânica - FEIS

Optimization of Large-Scale Hydrothermal System Operation

This paper presents the development of a mathematical model to optimize the management and operation of the Brazilian hydrothermal system. The system consists of a large set of individual hydropower plants and a set of aggregated thermal plants. The energy generated in the system is interconnected by a transmission network so it can be transmitted to centers of consumption throughout the country. The optimization model offered is capable of handling different types of constraints, such as interbasin water transfers, water supply for various purposes, and environmental requirements. Its overall objective is to produce energy to meet the country's demand at a minimum cost. Called HIDROTERM, the model integrates a database with basic hydrological and technical information to run the optimization model, and provides an interface to manage the input and output data. The optimization model uses the General Algebraic Modeling System (GAMS) package and can invoke different linear as well as nonlinear programming solvers. The optimization model was applied to the Brazilian hydrothermal system, one of the largest in the world. The system is divided into four subsystems with 127 active hydropower plants. Preliminary results under different scenarios of inflow, demand, and installed capacity demonstrate the efficiency and utility of the model. From this and other case studies in Brazil, the results indicate that the methodology developed is suitable to different applications, such as planning operation, capacity expansion, and operational rule studies, and trade-off analysis among multiple water users. DOI: 10.1061/(ASCE)WR.1943-5452.0000149. (C) 2012 American Society of Civil Engineers.

Análise crítica e métodos para avaliação da competição portuária entre terminais de contêineres.

Uma compreensão aprofundada da dinâmica de competição portuária é particularmente importante dado o contexto atual do setor, que orienta à outorga de novos portos e terminais no Brasil, à luz da Nova Lei dos Portos, Lei Nº 12.815 de 2013. A avaliação dos reais impactos decorrentes do aumento de capacidade portuária em cada região será atividade fundamental para que, por um lado, o poder público oriente a alocação efetiva de recursos, sem prejudicar a operação dos complexos existentes; e para que a iniciativa privada, por sua vez, possa compreender os impactos dos possíveis novos empreendimentos sobre as suas operações e delinear estratégias comerciais compatíveis com o novo cenário competitivo. A partir de extensa revisão bibliográfica e da aplicação de técnicas a casos específicos, o presente trabalho detalha a dinâmica competitiva entre terminais de contêineres e avalia criticamente seis métodos utilizados para identificar a existência de competição: correlação de market share, comparação de taxas de ocupação, sobreposição de escalas marítimas, comparação de custos logísticos terrestres, representatividade da região de influência contestável e existência de poder de mercado sobre a região de influência. Dos seis métodos analisados, dois apresentam conclusões fulminantes para a questão, embora sua aplicação demande grande volume de informações; um é assertivo em condições normais de distribuição geográfica de cargas; dois apresentam condições necessárias, porém não suficientes para a identificação de competição; e um deve ser aplicado com ressalvas, uma vez que pode levar a conclusões equivocadas.

Human mesenchymal stem cells retain multilineage differentiation capacity including neural marker expression after extended in vitro expansion

The suitability of human mesenchymal stem cells (hMSCs) in regenerative medicine relies on retention of their proliferative expansion potential in conjunction with the ability to differentiate toward multiple lineages. Successful utilisation of these cells in clinical applications linked to tissue regeneration requires consideration of biomarker expression, time in culture and donor age, as well as their ability to differentiate towards mesenchymal (bone, cartilage, fat) or non-mesenchymal (e.g., neural) lineages. To identify potential therapeutic suitability we examined hMSCs after extended expansion including morphological changes, potency (stemness) and multilineage potential. Commercially available hMSC populations were expanded in vitro for > 20 passages, equating to > 60 days and > 50 population doublings. Distinct growth phases (A-C) were observed during serial passaging and cells were characterised for stemness and lineage markers at representative stages (Phase A: P+5, approximately 13 days in culture; Phase B: P+7, approximately 20 days in culture; and Phase C: P+13, approximately 43 days in culture). Cell surface markers, stem cell markers and lineage-specific markers were characterised by FACS, ICC and Q-PCR revealing MSCs maintained their multilineage potential, including neural lineages throughout expansion. Co-expression of multiple lineage markers along with continued CD45 expression in MSCs did not affect completion of osteogenic and adipogenic specification or the formation of neurospheres. Improved standardised isolation and characterisation of MSCs may facilitate the identification of biomarkers to improve therapeutic efficacy to ensure increased reproducibility and routine production of MSCs for therapeutic applications including neural repair.

Expansion on specific substrates regulates the phenotype and differentiation capacity of human articular chondrocytes

In this study, we investigated if monolayer expansion of adult human articular chondrocytes (AHAC) on specific substrates regulates cell phenotype and post-expansion multilineage differentiation ability. AHAC isolated from cartilage biopsies of five donors were expanded on plastic dishes (PL), on dishes coated with collagen type II (COL), or on slides coated with a ceramic material (Osteologic, OS). The phenotype of expanded chondrocytes was assessed by flow cytometry and real-time RT-PCR. Cells were then cultured in previously established conditions promoting differentiation toward the chondrogenic or osteogenic lineage. AHAC differentiation was assessed histologically, biochemically, and by real-time RT-PCR. As compared to PL-expanded AHAC, those expanded on COL did not exhibit major phenotypic changes, whereas OS-expanded cells expressed (i) higher bone sialoprotein (BSP) (22.6-fold) and lower collagen type II (9.3-fold) mRNA levels, and (ii) lower CD26, CD90 and CD140 surface protein levels (1.4-11.1-fold). Following chondrogenic differentiation, COL-expanded AHAC expressed higher mRNA levels of collagen type II (2.3-fold) and formed tissues with higher glycosaminoglycan (GAG) contents (1.7-fold), whereas OS-expanded cells expressed 16.5-fold lower collagen type II and generated pellets with 2.0-fold lower GAG contents. Following osteogenic differentiation, OS-expanded cells expressed higher levels of BSP (3.9-fold) and collagen type I (2.8-fold) mRNA. In summary, AHAC expansion on COL or OS modulated the de-differentiated cell phenotype and improved the cell differentiation capacity respectively toward the chondrogenic or osteogenic lineage. Phenotypic changes induced by AHAC expansion on specific substrates may mimic pathophysiological events occurring at different stages of osteoarthritis and may be relevant for the engineering of osteochondral tissues.

Adult human articular chondrocytes in a microcarrier-based culture system : expansion and redifferentiation

xpanding human chondrocytes in vitro while maintaining their ability to form cartilage remains a key challenge in cartilage tissue engineering. One promising approach to address this is to use microcarriers as substrates for chondrocyte expansion. While microcarriers have shown beneficial effects for expansion of animal and ectopic human chondrocytes, their utility has not been determined for freshly isolated adult human articular chondrocytes. Thus, we investigated the proliferation and subsequent chondrogenic differentiation of these clinically relevant cells on porous gelatin microcarriers and compared them to those expanded using traditional monolayers. Chondrocytes attached to microcarriers within 2 days and remained viable over 4 weeks of culture in spinner flasks. Cells on microcarriers exhibited a spread morphology and initially proliferated faster than cells in monolayer culture, however, with prolonged expansion they were less proliferative. Cells expanded for 1 month and enzymatically released from microcarriers formed cartilaginous tissue in micromass pellet cultures, which was similar to tissue formed by monolayer-expanded cells. Cells left attached to microcarriers did not exhibit chondrogenic capacity. Culture conditions, such as microcarrier material, oxygen tension, and mechanical stimulation require further investigation to facilitate the efficient expansion of clinically relevant human articular chondrocytes that maintain chondrogenic potential for cartilage regeneration applications.

The role of university research centres in building road safety capacity : implications for China

In recent decades, highly motorised countries, such as Australia, have witnessed significant improvements in population health through reductions in fatalities and injuries from road traffic crashes. In Australia, concerted efforts have been made to reduce the road trauma burden since road fatalities reached their highest level in in the early 1970s. Since that time, many improvements have been made drawing on various disciplines to reduce the trauma burden (e.g., road and vehicle design, road user education, traffic law enforcement practices and enforcement technologies). While road fatalities have declined significantly since the mid-1970s, road trauma remains a serious public health concern in Australia. China has recently become the largest car market in the world (Ma, Li, Zhou, Duan, & Bishai, 2012). This rapid motorisation has been accompanied by substantial expansion of the road network as well as a large road trauma burden. Road traffic injuries are a major cause of death in China, reported as accounting for one third of all injury-deaths between 2002 and 2006 (Ma et al., 2012). In common with Australia, China has experienced a reported decline in fatalities since 2002 (see Hu, Wen & Baker, 2008). However, there remains a strong need for action in this area as rates of motorisation continue to climb in China. In Australia, a wide range of organisations have contributed to the improvements in road safety including government agencies, professional organisations, advocacy groups and research centres. In particular, Australia has several highly regarded and multi-disciplinary, university-based research centres that work across a range of road safety fields, including engineering, intelligent transportation systems, the psychology of road user behaviour, and traffic law enforcement. Besides conducting high-quality research, these centres fulfil an important advocacy role in promoting safer road use and facilitating collaborations with government and other agencies, at both the national and international level. To illustrate the role of these centres, an overview will be provided of the Centre for Accident Research and Road Safety-Queensland (CARRS-Q), which was established in 1996 and has gone on to become a recognised world-leader in road safety and injury prevention research. The Centre’s research findings are used to provide evidence-based recommendations to government and have directly contributed to promoting safer road use in Australia. Since 2006, CARRS-Q has also developed strong collaborative links with various universities and organisations in China to assist in building understanding, connections and capacity to assist in reducing the road trauma burden. References Hu, G., Wen, M., Baker, T. D., & Baker, S. P. (2008). Road-traffic deaths in China, 1985–2005: threat and opportunity. Injury Prevention, 14, 149-153. Ma, S., Li, Q., Zhou, M., Duan, L., & Bishai, D. (2012). Road Traffic Injury in China: A Review of National Data Sources. Traffic Injury Prevention, 13(S1), 57-63.

Multi-objective models and techniques for analysing the absolute capacity of railway networks

Railway capacity determination and expansion are very important topics. In prior research, the competition between different entities such as train services and train types, on different network corridors however have been ignored, poorly modelled, or else assumed to be static. In response, a comprehensive set of multi-objective models have been formulated in this article to perform a trade-off analysis. These models determine the total absolute capacity of railway networks as the most equitable solution according to a clearly defined set of competing objectives. The models also perform a sensitivity analysis of capacity with respect to those competing objectives. The models have been extensively tested on a case study and their significant worth is shown. The models were solved using a variety of techniques however an adaptive E constraint method was shown to be most superior. In order to identify only the best solution, a Simulated Annealing meta-heuristic was implemented and tested. However a linearization technique based upon separable programming was also developed and shown to be superior in terms of solution quality but far less in terms of computational time.

Water management capacity building to support rapidly developing mining economies

Many developing countries are experiencing rapid expansion in mining with associated water impacts. In most cases mining expansion is outpacing the building of national capacity to ensure that sustainable water management practices are implemented. Since 2011, Australia's International Mining for Development Centre (IM4DC) has funded capacity building in such countries including a program of water projects. Five projects in particular (principally covering experiences from Peru, Colombia, Ghana, Zambia, Indonesia, Philippines and Mongolia) have provided insight into water capacity building priorities and opportunities. This paper reviews the challenges faced by water stakeholders, and proposes the associated capacity needs. The paper uses the evidence derived from the IM4DC projects to develop a set of specific capacity-building recommendations. Recommendations include: the incorporation of mine water management in engineering and environmental undergraduate courses; secondments of staff to suitable partner organisations; training to allow site staff to effectively monitor water including community impacts; leadership training to support a water stewardship culture; training of officials to support implementation of catchment management approaches; and the empowerment of communities to recognise and negotiate solutions to mine-related risks. New initiatives to fund the transfer of multi-disciplinary knowledge from nations with well-developed water management practices are called for.