As superligas de níquel apresentam boa combinação de resistência à corrosão e à oxidação, resistência mecânica, resistência à fadiga e resistência à fluência. Além disso, apresentam bom desempenho operacional em temperaturas próximas à temperatura de fusão da liga. Estudos apontam à possibilidade de se obter aço carbono revestido com a superliga de níquel Inconel 625 pelo processo de cladeamento e pelo processo de aspersão térmica. A presença de molibdênio na composição química do Inconel625 garante excelente resistência à corrosão por pites e por fresta, enquanto o nióbio confere alta soldabilidade e resistência à corrosão intergranular a essas ligas. O processo de soldagem é amplamente usado em processos industriais e pode ser aplicado em uma junta Inconel-Inconel, podendo modificar alguma propriedade dessa liga. O objetivo do presente trabalho é estudar uma junta soldada de Inconel 625, obtida pelo processo de soldagem por fusão a arco elétrico com o uso de eletrodo revestido ENiCrMo-3, quanto à morfologia estrutural, à dureza e à resistência à corrosão. A morfologia foi avaliada por microscopia óptica, por microscopia eletrônica de varredura e por espectroscopia de energia dispersiva. A propriedade mecânica de dureza foi avaliada a partir do perfil de microdureza Vickers ao longo da junta soldada Para avaliar a resistência à corrosão da junta soldada foram realizados os ensaios de polarização potenciodinâmica, reativação potenciodinâmica de varredura cíclica (norma ASTM G108-94), polarização potenciodinâmica cíclica e ensaio de imersão (norma ASTM G48-03). Também avaliou-se a susceptibilidade à corrosão por pites pela norma ASTM G61-86 a temperatura ambiente e a 90 ºC. Para a polarização potenciodinâmica, três diferentes eletrólitos foram empregados: 3,5% NaCl, 3,5% NaCl + 0,01 mol/L Na2S2O3 e 3,5% NaCl + 1M H2SO4. Os resultados obtidos mostraram que o metal de solda apresenta uma microestrutura dendrítica com precipitados de Nb e de Mo nas regiões interdendríticas. O desempenho quanto à resistência à corrosão foi satisfatório nos meios estudados, considerando as características dessas ligas. No entanto, a junta soldada apresentou maior suscetibilidade à corrosão por pites e à corrosão localizada comparativamente ao metal base. O filme passivo formado no metal base é melhor constituído do que o filme passivo formado no metal de solda. / Nickel superalloys show a good combination of corrosion, oxidation and creep resistance as well as mechanical and fatigue strength. These alloys can operate at temperatures close to their melting temperature. The Inconel 625 has desired characteristics for application in environments that require high corrosion resistance, such as in oil and gas exploitation. Some studies show the possibility of obtaining a coating of Inconel 625 onto carbon steel by the cladding process and by the thermal spray process. The molybdenum content in Inconel 625 ensures excellent resistance to pitting and crevice, while the niobium content gives high weldability to these alloys. The welding process is practically present in all industrial plants, so an Inconel-Inconel joint is unavoidable. However, the welding can lead to changes in the properties of these superalloys. Therefore, the present work aims to study the structural morphology, hardness and corrosion resistance of a welded joint of Inconel 625 obtained by the electric arc fusion welding process with ENICrMo-3 covered electrode. The morphology was evaluated by optical microscopy, scanning electron microscopy and dispersive energy spectroscopy. Hardness was studied by Vickers microhardness profile along the welded joint. In order to evaluate the corrosion resistance of the welded joint, the Potentiodynamic polarization, potentiodynamic cyclic sweep reactivation (ASTM G108-94), cyclic potentiodynamic polarization and immersion test (ASTM G48-03) were performed Also susceptibility to pitting corrosion was assessed by ASTM G61-86 at room temperature and at 90 ° C. Potentiodynamic polarization curves were performed in three different solutions to evaluate the corrosion resistance: 3.5% NaCl, 3.5% NaCl + 0.01 mol / L Na2S2O3 and 3.5% NaCl + 1M H2SO4 The results show that the weld metal has a dendritic microstructure with precipitates of Nb and Mo in the interdendritic regions. The corrosion performance in environments close to the environments of possible applications was satisfactory considering the resistance of these alloys, but the specific welded joint was more susceptibility to corrosion by pits and localized corrosion. The passive film formed in the base metal was better formed than the passive film formed in the welded metal.

Superligas à base de níquel vêm sendo extensivamente utilizadas em diversas aplicações nas indústrias devido ao excelente comportamento mecânico e anticorrosivo. No entanto, essas ligas possuem certas particularidades que levam à necessidade de desenvolvimento de técnicas de inspeção e caracterização metalúrgica, como forma de garantir a integridade estrutural dos componentes fabricados com essas ligas. Neste trabalho, a técnica de correntes parasitas foi aplicada à superligas à base de níquel com duas propostas distintas: 1) Em um primeiro momento foi realizado o estudo da evolução microestrutural da liga Inconel 718 durante o processo de envelhecimento através da combinação do ensaio por correntes parasitas, análise de difração de raios-X, análise metalográfica, medidas de dureza e tamanho de grão. As medidas foram realizadas em amostras submetidas a diferentes ciclos de tratamentos térmicos variando entre 620-1035°C. Os resultados mostraram que as diferentes microestruturas do Inconel 718 têm efeitos distintos na condutividade elétrica quando medidos através da técnica de correntes parasitas. A influência da microestrutura na condutividade pode ser mostrada sendo devido à competição de dois efeitos sobre o espalhamento de elétrons: a purificação da matriz e a morfologia, distribuição e tamanho dos precipitados. A combinação dos valores de dureza e condutividade elétrica provou ser uma forma rápida e prática de determinar o nível de envelhecimento da liga; 2) Em um segundo momento foi desenvolvido um processo de otimização de sensores através de modelagem por elementos finitos (MEF). Através de uma metodologia de otimização, os parâmetros de construção e operação de um sensor foram otimizados para inspeção de defeitos superficiais e subsuperficiais esperados em materiais cladeados com Inconel 625. O sensor com a geometria ótima foi construído e testado a fim de verificar a eficiência do processo de otimização. Uma ótima correlação entre os resultados numéricos e experimentais foi encontrada e o sensor ótimo se mostrou eficiente na inspeção de pequenos defeitos superficiais e subsuperficiais na liga Inconel 625 quando operado nas frequências apropriadas. / Nickel-based superalloys have been extensively used in various industries due to its unique mechanical and corrosion behavior. However, these alloys show particular characteristics which lead to the need for specific inspection and metallurgical characterization techniques in order to ensure the structural integrity of components manufactured from these alloys. In this work , the eddy current technique was applied to nickel-base superalloys with two aims: 1 ) Firstly, the microstructural evolution of Inconel 718 during aging processes has been studied through a combination of eddy current testing, X-ray diffraction analysis, metallography, hardness and grain size measurements. Measurements were carried out in samples subjected to different heat treatment cycles between 620-1035°C. Results show that different microstructures of Inconel 718 have a distinguishable effect on electrical conductivity when this is measured through an appropriately sensitive technique (i.e. eddy current testing). The influence of microstructure on conductivity could be shown to be due to the competition between two effects on the scattering of electrons: matrix purification and precipitate size, distribution and morphology. A combination of hardness values and electrical properties proved to be a fast and practical way of determining the stage of aging of the alloy; 2) An optimization method of eddy current sensor design was developed through finite element modeling (FEM). Through a methodology of optimization, the construction and operation parameters of the sensor were optimized for inspection of superficial and subsuperficial defect, commonly found in weld overlay Inconel 625 claddings. A prototype of this sensor with the optimum geometry was built and tested on blocks identical to those considered in the models in order to verify the efficiency of the optimization process. A very good agreement between numerical and experimental results was found. Moreover, the optimal sensor was efficient to detect small surface and subsurface defects in Inconel 625 when operated at appropriate frequencies.

L’amélioration de la fluidité du trafic aux intersections a reçu une attention particulière depuis près d’un siècle. Avec la perspective de véhicules contrôlés et communicants, la régulation aux intersections connaît un nouvel essor. Dans cette thèse nous nous intéressons à la régulation coopérative des intersections par la synchronisation des vitesses. Afin d’éviter des arrêts inutiles aux intersections, les véhicules régulent leur vitesse en fonction non seulement des véhicules qui les devancent sur la même voie mais aussi des véhicules prioritaires provenant des autres voies en conflit. La synchronisation des vitesses grâce à la communication sans-fil a plusieurs avantages mais pour les exploiter pleinement, il est nécessaire d’aborder les problématiques des commandes longitudinale et latérale des véhicules. En ce qui ce concerne la commande longitudinale, la thèse s’intéresse à deux problématiques. Pour des raisons évidentes de sécurité, les délais de communication sans-fil avec les véhicules des autres voies, à savoir hors de la portée des capteurs, doivent être pris en compte. Pour ce faire, la commande longitudinale adoptée est une fonction non linéaire qui considère un temps maximal de communication et une borne de décélération. Si les contraintes ne sont pas respectées, la fonction déclenche l’arrêt du véhicule. Etant donné que les résultats de simulations sont concluants dans des cas extrêmes, la thèse aborde la problématique de fluidité du trafic à base de la commande proposée. En effet, le comportement du trafic dépend du choix du lieu où commence la synchronisation des vitesses. La thèse discute les deux approches classiques et propose une solution intermédiaire. Sur un circuit sous la forme d’un huit, l’approche proposée permet de réduire considérablement le recours au freinage contrairement aux deux autres approches actuelles. En ce qui concerne la commande latérale, l’intersection pose deux problèmes. Le premier est la limite du champ de vision à cause des courbures serrées des mouvements tournant et la deuxième est le délai du traitement par les caméras. Dans ce sens, la thèse propose une commande basée sur le calcul de la courbure de Frenet couplé à la correction des écarts. Le suivi des courbures et la correction sont tous les deux déduit à partir du mouvement circulaire induit par l’angle du volant. Les avantages de cette approche par rapport aux approches classiques (LQRwFF et Stanley) est d’une part, de ne pas être gourmande en termes de champs de vision nécessaire et d’autre part d’avoir des contraintes temps-réels plus souples que les approches de la littérature. La comparaison avec les techniques actuelles démontrent que notre approche, dans des conditions de circulation urbaine est capable de résister à des temps d’échantillonnage plus longs contrairement aux deux autres avec une visibilité plus faible. / In this thesis, we are interested in the cooperative intersection management by synchronizing the velocities of conflict vehicles. Thanks to the wireless communication, the synchronization of velocities has several advantages. But, for the purpose of full exploiting them, it is necessary to address at first the problems of the longitudinal and lateral control of vehicles. For the longitudinal control, the delay of wireless communication with the vehicles on other routes must be taken into account. The adopted longitudinal control is non-linear function that considers a maximum communication time and a deceleration boundary.The simulation results in extreme cases have concluded that the thesis addresses the problem of traffic fluidity. Indeed, the behavior of the traffic flow depends on the choice of the place where the synchronization of the speeds begins. The thesis discusses the two classical approaches and proposes a smoothing solution that significantly reduces the use of braking contrary to the two existing approaches. For the lateral control of vehicle at intersection, the thesis proposes a control based on the calculation of Frenet curvature coupled with correction of deviation from tracking path. Both the curve tracking and the correction are deduced from the circular motion induced by the steering wheel angle. The advantages of this approach compared to traditional approaches are to be not greedy in terms of the necessary field of vision and to have more flexible real-time constraints.

This thesis deals with the heat evolution duringsolidification and its relation to the formation of porosity.It intends to improve the current understanding of theformation of porosity in cast materials with special interestin nodular cast iron and the spray forming process. Twodifferent systems, a Fe-based alloy, Cast iron, and a Ni-basedalloy, Inconel 625, are examined. The effect on the heatevolution of the morphology and the processing parameters inspray forming are treated. An evaluation of the microstructural features, segregationbehavior and physical properties such as latent heat of fusionis performed byusing thermal analysis under cooling ratesranging from 0.1 to 104 K/s. In order to achieve this amodified differential thermal analysis (DTA) equipment, amirror furnace and levitation casting are used. Results arepresented in terms of the fraction of solidified, the coolingrate and the microstructure observed. The measured latent heatof fusion is not constant throughout the solidificationprocess. Variations in morphology and cooling rate affect therelease of the latent heat. A thermodynamic model is used to describe the experimentalobservations and to explain the formation of pores in nodularcast iron by taking into consideration the formation of latticedefects during the liquid/solid transformation. In this casethe formation of porosity is regarded as a consequence ofchanges in the volume fraction ratio graphite/ during thesolidification process. A numerical model of the spray forming process is developedby means of CFD modelling and compared with experimentalmeasurements performed in an industrial facility. Stagnationpressure measurements provided information about the gas flowvelocity and an analysis of the overspray powder providedinformation about the particle thermal history. Evaluation ofthe deposit was also performed. It is observed that the processconditions in spray forming promote non-equilibriumsolidification even though solidification at the deposit occursat a lower rate. In this case the porosity formed near theinterface substrate/deposit depends largely on the substratetemperature. The presence of certain reactive elements, such astitanium, affects the porosity levels in the rest of thedeposit. <b>Keywords:</b>Thermal Analysis, Nodular Cast Iron, Inconel625, CFD, Flow Assesment, Multiphase Flow, Spray Deposition,Microporosity, Superalloys

Los firmes permeables forman parte de la tendencia de construcción sosteniblecomo uno de los Sistemas Urbanos de Drenaje Sostenible (SUDS) más completos. Paraestudiar la capacidad de infiltración en laboratorio, se ha desarrollado el ensayo deresistencia a la colmatación con el Infiltrómetro Cántabro Fijo (ICF). Este ensayo es unaherramienta eficaz para la caracterización de diferentes tipos de pavimentos permeables,exponiéndolos a un aporte conocido de agua, variando el estado de colmatación y lainclinación de la superficie. Además, para estudiar la capacidad de infiltración encampo, se ha desarrollado el Infiltrómetro Cántabro Portátil (ICP), el cual permiteidentificar claramente cualquier tipo de superficie, permeable o impermeable, así comosu capacidad de infiltración. Respecto a la degradación de los materiales, se haanalizado la afección de los vertidos de hidrocarburos sobre mezclas bituminosasporosas fabricadas con distintos tipos de betunes. Por último, se han construido modelosde firmes permeables en el Laboratorio (FIDICA), en el Campus de Santander de laUniversidad de Cantabria y en el aparcamiento experimental de la Guía en Gijón. / Pervious pavements are part of the trend of sustainable construction as one of themost complete Sustainable Urban Drainage Systems (SUDS). The clogging resistancetest with the Fixed Cantabrian Infiltrometer (FCI) has been developed to study theinfiltration capacity in laboratory. The FCI is an effective tool for the characterization ofdifferent pervious pavements types, exposed to a known contribution of water, varyingclogging conditions and slope. Besides, the Portable Cantabrian Infiltrometer (PCI) hasbeen developed to study the infiltration capacity in field. The PCI allows clearlyidentifying any type of surface, pervious or impervious, as well as its clogging level.Regarding the materials degradation, the affection of hydrocarbons leakages overporous asphalt has been analysed. Lastly, models of pervious pavements have been builtin the FIDICA Laboratory and in the Santander Campus of the University of Cantabria,besides several experimental parking bays in La Guía, Gijón.

El control de Tráfico Urbano es altamento complejo y dinámico: depende de la cantidad, tipo y calidad de los datos recibidos, de las previsiones de datos a recibir, del comportamiento del tráfico (actual, pasado y en previsión), el conocimiento del control a aplicar y del entorno de actuación. En esta tesis doctoral se analizan las diferentes aproximaciones realizadas desde el ámbito de la Inteligencia Artificial para identificar las principales debilidades de estos sistemas. Como resultado de este análisis se propone una nueva aproximación basada en la integración de datos procedentes de distintos sensores (mediante la adopción de un modelo cualitativo de datos), el análisis en tiempo real de la situación del tráfico (mediante un simulador macroscópico cualitativo basado en la densidad de vehículos en cola a la entrada de las intersecciones), la identificación de problemas actuales y potenciales de tráfico (mediante un análisis temporal cualitativo de la evolución de la densidad de vehículos) y la sugerencia de ejecución de acciones de control de tiempos de rojo para reducir las congestiones de tráfico actuales, evitar que evolucionen a situaciones de colapso y evitar congestiones futuras. Se define y diseña un prototipo con arquitectura multiagente que integra las características mencionadas. Su implementación se realiza en un sistema distribuido COTS. La ejecución del prototipo en pruebas de laboratorio (con datos reales de la ciudad de Castellón de la Plana) proporciona resultados que avalan la aproximación realizada.

La incorporació de les noves Tecnologies de la Informació i la Comunicació (TIC) al camp de l'educació ha fet possible la creació de nous entorns per l'educació que faciliten els processos d'ensenyament i aprenentatge, afegint noves eines de treball i funcionalitats i fent possible la formació per a qualsevol individu de manera no presencial i asíncrona. En aquest sentit, la Universitat Oberta de Catalunya (UOC) és una universitat sorgida de la societat de la informació que disposa del seu propi entorn virtual d'aprenentatge, un laboratori únic per a la innovació docent. Seguint la “Declaració de Bolonya” i l'Espai Europeu d'Educació Superior (EEES), el model educatiu de la UOC està centrat en el concepte d'activitat com un mitjà per a que l'estudiant assoleixi noves competències i, cada vegada més, aposta per la flexibilitat i adaptació del procés d'aprenentatge. En aquest marc, el present treball de tesi fa servir les TIC com un mitjà per a facilitar els procés d'adquisició de competències de cada estudiant. Es proposa la creació d'itineraris formatius adaptatius (IFAs) mitjançant l'especificació IMS-Learning Design (IMS-LD) per treballar la formació adaptativa. Aquesta consisteix en proporcionar als estudiants, en cada moment, les activitats i els recursos que més s'ajusten al seu perfil, oferint a cada estudiant un itinerari concret de formació. Conseqüentment, es produeix una adaptació constant a la progressió de l'estudiant que pot afavorir el seu procés d'aprenentatge, esdevenint un primer pas cap a la personalització, un dels objectius de l'EEES. Amb aquest objectiu, es descriu com es realitza tant el disseny conceptual dels itineraris formatius adaptatius, com la seva creació i implementació amb IMS-LD. També es descriu el procés d'edició i execució dels itineraris amb les eines seleccionades (ReCourse i CopperCore) i es mostren les limitacions existents per implementar la formació adaptativa i com s'han abordat. Finalment, per demostrar la seva viabilitat i aplicació real en un entorn virtual d'aprenentatge, es realitzen dues proves pilot en el marc dels estudis d'Informàtica, Multimèdia i Telecomunicació a la UOC. En aquestes proves pilot s'han implementat diferents itineraris formatius adaptatius creats amb IMS-LD, proporcionant les bases d'un primer pas cap a la introducció de la formació adaptativa en l'educació superior. / The inclusion of Information and Communication Technologies (ICT) in the field of education has made possible the creation of new environments for education that facilitate the processes of teaching and learning, adding new tools and features and making possible training for any individual using a distance and asynchronous model. The Open University of Catalonia (UOC) is a university arising from the information society that has its own virtual learning environment, a unique laboratory for educational innovation. Following the ``Bologna Declaration'' and the European Higher Education Area (EHEA), the UOC's educational model is centered on the concept of activity as a means for the student to achieve new competences and, as a distance learning institution, the UOC is increasingly committed to flexibility and adaptability of the learning process. In this context, this thesis tries to facilitate the learning process of each student by means of ICT. The work presented proposes adaptive learning paths using IMS-Learning Design (IMS-LD) in order to achieve adaptive learning. Adaptive learning provides students, at all times, activities and resources that best fits their profile, giving each student a specific learning path. Consequently, there is a constant adaptation to the progression of the students that can facilitate their learning process, becoming a first step towards personalization, one of the EHEA main objectives. Our proposal describes the conceptual design of adaptive learning paths as well as their creation and implementation using IMS-LD. It also analyzes the edition and run-time processes of the adaptive learning paths using the selected tools (ReCourse and CopperCore) showing their limitations when this adaptive scenario is taken into account and providing solutions to the encountered shortcomings. Finally, as a proof of concept, we present two different experiments performed with subjects of the department of Computer Science, Multimedia and Telecommunications of the UOC. In these experiments, different adaptive learning paths have been implemented and tested using IMS-LD, providing the basis for a first step towards the introduction of adaptive learning paths in higher education.

El reciclado de los pavimentos asfálticos deteriorados no es una idea nueva, no obstante, con el aumento de las exigencias medioambientales y económicas se ha convertido en una alternativa cada vez más utilizada por diferentes países en todo el mundo. Durante las últimas décadas, principalmente a partir de la crisis del petróleo de 1973, se han llevado a cabo grandes esfuerzos para desarrollar técnicas de reutilización de materiales procedentes del fresado de capas de firmes envejecidos, lo cual permite reducir la cantidad de betún y áridos empleados en la fabricación de nuevas mezclas bituminosas, así como disminuir los vertidos de materiales de desperdicio, lo que representa grandes ventajas ecológicas y económicas.Tomando en cuenta lo anterior, la escasa experiencia que se tenía en España en el reciclado de mezclas bituminosas en caliente en planta, y la falta de normativa específica para la fabricación de este tipo de mezclas, se decidió realizar en el Laboratorio de Caminos de la U.P.C., un completo estudio de las características mecánicas de diferentes tipos de mezclas recicladas en caliente en planta, añadiendo diferentes porcentaje de material fresado (MBR) y utilizando diferentes ligantes y/o agentes rejuvenecedores, comparando su comportamiento con el de mezclas convencionales, para lograr definir criterios de diseño, dosificación y control de fabricación que permitan garantizar un comportamiento adecuado de estas mezclas.Algunos de los ensayos realizados se utilizan para el diseño y control de calidad de mezclas convencionales, tal es el caso del Marshall, Tracción Indirecta o Flexotracción, pero también se utilizaron algunos ensayos menos conocidos pero que aportan información muy valiosa como el UCL , o el Barcelona Tracción Directa BTD.A través del análisis de toda la información obtenida en este trabajo se ha podido comprobar que las mezclas recicladas pueden alcanzar un comportamiento prácticamente equivalente al de las mezclas convencionales, siempre y cuando se tenga el suficiente cuidado en su diseño, y proceso de fabricación. Por otra parte, se han podido establecer algunos parámetros que serán de gran ayuda para el diseño y control de calidad de las mezclas recicladas en caliente en planta, ayudando al impulso del empleo de esta técnica en los proyectos de construcción y rehabilitación de firmes bituminosos en España.

The most common decisions to be taken in the design of logistic systems are related to the location of facilities and the management of vehicle fleets.In this thesis, we study three of the optimization problems arising around this kind of decisions; namely the LRP, the SGAP and the SLRP. The first problem analyzed in this work is a capacitated LRP with one single uncapacitated vehicle at each open plant. To model this problem we resort to an auxiliary network that allows us to represent feasible solutions as families of paths satisfying a series of side constraints.The solutions of a reinforced LP relaxation of this model are used as the basis of a rounding heuristic designed to build feasible solutions of the problem. Those solutions are then improved with a TS heuristic.Two lower bounds, distinct from that obtained with the LP relaxation of the model, are proposed for this problem. The first one is obtained by bound ing separately the two different parts of the cost of any feasible solution, namely the fixed costs for opening plants and the route costs. The second lower bound is the result of applying CG to the Lagrangian dual obtained by dualizing the assignment constraints. The pricing problem obtained from our formulation is an ESPPRC. The complexity of this problem, and the fact that optimality of the obtained solutions is not always necessary, have motivated us to develope a simple heuristic for it.The computational experiences show a very good behavior of the TS procedure both, for the computational effort required and the quality of the solutions. The first lower bound proposed gives satisfactory results in reasonable amounts of time. In the case of the CG approach, results are very encouraging. In some of the tested instances the program terminated because of the CPU time limit specification, before succeeding to find a valid lower bound.In those instances, the algorithm was always stalled in the exact resolution of an ESPPRC. The difficulties encountered to solve this problem represent a limitation of this approach and suggest the future study of alternative solution methods. In spite of this limitation, in a high proportion of the instances the algorithm succeeded, and the final gap between the upper and the lower bound was always 0. The success in these instances is partially due to the use of our heuristic to generate new columns whenever this is possible.The second problem studied in this thesis is a SGAP. In this assignment problem the jobs are interpreted as customers that can request a service with a given probability, and each agent can serve a limited number of customers. This uncertainty about the presence of each customer is represented by modelling the demands of the customers as Bernoulli distributed independent random variables. The problem consists of finding an a priori assignment of customers to agents. Once the actual requests for service are known, an adaptive action is taken to tackle violations of the capacity constraints. On the one hand, part of the customers assigned to overloaded agents can be reassigned. On the other hand, some of the service requests can be disregarded. Different penalties for reassignment and for unattended service requests are pre-specified. The problem is formulated as a recourse model, where the recourse function gives the expected penalties for reassignments and unattended service requests.Since this recourse function is defined as the expected value of an integer programming recourse model, it does not have the regularity properties characteristic of those defined by linear recourse models. To overcome the difficulties caused by this, we construct a convex approximation of the recourse function that is tight in all feasible points. Moreover, as illustrated in the computational experiences, the use of this approximation reduces the computational effort required to evaluate the recourse function is some orders of magnitude. The convex approximation of the recourse function allows us to adapt the well-known L-shaped method to our problem. Integrality of the first stage variables is tackled in three different ways, giving raise to three versions of the algorithm. The difference among them resides in the hierarchy between the branching and the addition of violated cuts. On the one hand, we present a version where cuts are only added when integer solutions are found. On the other hand, a version is proposed where branching is only performed when no more violated cuts can be identified. The remaining version is designed as a tradeoff of these two; at each node of the search tree, new optimality cuts are added, if needed, and branching is performed if the solution at hand is fractional. Computational experiences point out this last version as the best of the three, since the efforts devoted to obtain a rich approximation of the recourse function and to achieve integrality are more balanced.We have also derived both, lower and upper bounds for this specific SGAP. Upper bounds are obtained from three simple heuristics. All them are based on solving deterministic approximations of the SGAP and provide good quality solutions in small amounts of CPU time. A lower bound is derived from a family of linear stochastic subproblems. Althoug in some of the tested instances the gap between the bounds exceeded the 30%, in the general case we obtained small gaps.One of the heuristics was used in the exact algorithm to provide it with a good upper bound. The lower bound is also used in the three versions of the algorithm, as the basis of some of the optimality cuts and also to identify optimal solutions. The quality of these bounds is one of the factors that explain the success of the exact algorithm.The last problem studied in this thesis is a SLRP. The stochasticity considered here is of the same type as that considered for the SGAP. Again, customers may request a service with a given probability and this is modeled by introducing Bernoulli random variables to represent the demands. A two stage model is proposed for this problem. In a first stage, a set of plants to open has to be chosen together with a family of disjoint routes (one rooted at each open plant) that visit all the customers. In the second stage, once all the demands become available, the actual routes have to be designed. For plants whose number of service requests does not exceed the capacity, the actual route is derived from that designed a priori by skipping customers with no demand. When the requests for service allocated to a plant exceed its capacity, a subset of them is randomly chosen to be served, and they are visited in the order defined by the a priori route.Penalties are paid for the unattended service requests. The expected total cost of the actual routes and the expected penalties for unserviced customers are contained in the recourse function.We present a two phase heuristic to solve this problem. In the first phase, a series of subproblems are sequentially solved to build an initial solution. In the second phase, this solution is successively improved using LS. This improving phase requires a high number of evaluations of the recourse function. Although we have developed an analytical expression for this recourse function, the computational effort required for its evaluation is considerable due to its combinatorial nature. For this reason, we approximate it with a simpler auxiliary function that has allowed us to obtain solutions in small computational times.We also propose a lower bound obtained from bounding different parts of the objective function independently. Unfortunately, we only could find reasonable bounds for the sum of fixed costs for opening the plants plus the expected penalty paid for unserviced customers. Further research is intended to improve the bounding of the expected total cost of the routes.The evaluation of the quality of the solutions obtained with our heuristic is not easy due to the lack of a tight global lower bound. However, the partial bound on the costs relative to the plants allows to conclude that the heuristic makes in general a good choice of the set of plants. As for the allocation of customers to plants and the design of the routes we can only evaluate the evolution along the search. In the computational experiences reported it can be seen that this evolution is satisfactory.

En el mundo de la logística de distribución del automóvil, donde el costo financiero de la inmovilización del producto es muy alto, y tomando como base los cambios tecnológicos en sistemas de información habidos en los últimos años, se estudia la necesidad de plantear los procesos de trabajo en las grandes terminales de vehículos, de tal manera que estas terminales puedan gestionar y compartir su información de forma ágil y eficiente. Durante años se ha recomendado a las empresas el fortalecimiento de sus enlaces en la cadena logística hasta llegar al cliente final. Los grandes fabricantes de vehículos han realizado importantes inversiones en tecnologías de la información y las terminales de vehículos como eslabón de la cadena de suministro que son, han de estar al mismo nivel tecnológico que sus clientes. Por ello se plantea cual es el estado actual de los sistemas de información de las terminales marítimas de vehículos en el estado español, y cual debe ser la estrategia de integración de sus sistemas y procesos más adecuada para trabajar de acuerdo con los parámetros de eficiencia, integración, calidad y reducción de costes que los grandes fabricantes de automóviles imponen en un entorno de fuerte competencia.Se procede pues a la definición exhaustiva de parámetros de eficiencia logística (a nivel Puerto, a nivel Terminal y a nivel de flujos de información) y al estudio de la situación actual de las terminales, centrándonos en el análisis de cómo funcionan a nivel de procesos y en que tipo de estructura de sistemas de información se apoyan. En este punto, se hace especial hincapié a los procesos y flujos de información que se llevan a cabo en la terminal de vehículos, encontrando que actualmente dichos procesos se realizan sobre sistemas de información (entornos o programas informáticos) que no están integrados entre sí.Así pues se plantean dos objetivos claramente diferenciados:· Demostrar la necesidad de la integración de sus sistemas de información, como única salida competitiva para las terminales de vehículos; de modo que la captura, gestión y volcado de datos pueda realizarse de forma integrada.· Plantear y desarrollar una propuesta previa al desarrollo de un módulo operativo, que gestione las operaciones y procesos productivos de la terminal de forma integrada; definiendo las interacciones entre los diferentes módulos que afectan a la propuesta del módulo operativo.Se pone de manifiesto a lo largo de la tesis la necesidad actual para los operadores portuarios de estar a la altura de gestión de la información que la comunidad logística está adquiriendo, con el reto de la agilización de los trámites documentales y de la información, para conseguir que el flujo documental sea tan rápido como el tráfico físico de las mercancías.La forma de organizar, manejar y compartir la información de o hacia los clientes es de vital importancia en una terminal de vehículos, dando por sentado que la calidad en la manipulación y el mejor precio posible frente a la competencia ya están conseguidos. Para lograr la agilidad máxima a la hora de gestionar la información, es necesario encaminarse por dos vías diferentes pero complementarias:· La reingeniería de los procesos: Reorganizando la forma de trabajar.· La integración de los sistemas de información: Lo que requiere en primer lugar un cuidadoso examen de la forma de trabajar actual, la definición de la nueva forma propuesta de llevar a cabo los procesos, y finalmente la elección de un proveedor de tecnología de la información para sustentar todo lo anterior.Se razona la elección del sistema de gestión de la información, y del producto más adecuado para cumplir con los requerimientos definidos.Por último, se plantean todos los procesos que afectan a las Terminales objeto de la tesis, de cara a su integración de un módulo de gestión de operaciones. / In the nowadays world of the car distribution logistics, where the financial cost of the immobilization of the product is so high, and taking as base the technological changes on information systems been in the last years, it is presently studied the necessity to raise the processes of work in the biggest car terminals, in such a way that these port terminals could manage and share their information on agile and efficient form. During years the fortification of its connections in the logistic chain until arriving at the final client has been recommended to the companies. The great companies manufacturers of vehicles, have made important investments in the technologies of the information field, and the port terminals of vehicles, as part of the provision chain that they are, have to be at the same technological level that its clients. For that reason the thesis considers which is the actual state of the information systems at the port car terminals in Spain, and which must be the best integration strategy of its systems and processes, to work in agreement with the efficiency parameters of integration, quality and reduction of costs that the great manufacturers of automobiles impose in such a market of strong competitiveness. It is proceed then to the exhaustive definition of logistic efficiency parameters (at Port level, at Terminal level and flows of information level) and the study of the nowadays situation in the car terminals, focusing on the analysis of how their processes work, and which kind of structure of information systems they lean. At this point, it is special emphasis made to the processes and flows of information that are carried out at the car terminals, finding out that at this moment these processes are made performed on information systems (computer surroundings or programs) which are not integrated one to each other. Therefore two differentiated objectives are clearly considered: &#61607; To demonstrate the necessity of the integration of its information systems, like the only competitive exit for the terminals of vehicles; so that the capture, management, and report of data could be made in a integrated way. &#61607; To raise and develop a previous proposal to the development of an operative module, that could manage the operations and productive processes of the terminal in an integrated way; defining the interactions between the different modules that affect present proposal of the operative module. It is stated throughout the thesis, the present necessity for harbour operators to be at same level of efficiency in information management that the rest of logistic community is achieving, including the challenge of the speeding up of the documentary and information proceedings, in order to achieve that the documentary flow is as fast as the physical traffic of the goods. The way to organize, manage and share the information from or towards the clients is a vital importance matter in a car terminal, taking for granted that the highest quality in the handling and best possible prices are already offered. In order to obtain the maximum quickness in information managing, it is necessary to move by two different but complementary paths:· Processes reengineering: Reorganizing the means of working. · The Information systems integration: What requires in the first place a careful examination of the way to work at present time, the definition of the new way proposed to carry out the processes, and finally the election of a technology supplier to sustain all the previous jobs. Finally, all the Terminal processes which affect the object of the thesis are raised, for its integration of a module of management of operations.