Fuzzy Inductive Reasoning (FIR) is a modelling and simulation methodology capable of generating a qualitative input-output model of a system from real-valued trajectories of its physical variables. The functioning basis of FIR is to qualitatively learn the behaviour of a system from its past real data. This is an interesting feature when dealing with ill-defined, usually large-scale systems, for which an accurate description is not available but only data trajectories of the process.FIR finds in a (huge) search space model the so-called optimal mask that indicates which variables best explain any given output. Unfortunately, any algorithm that can find the optimal mask is necessarily of exponential complexity, i.e., the number of masks to be visited grows exponentially with the number of available input variables. This makes the FIR methodology, in its actual implementation, impractical for those cases in which it would be most useful, i.e., large-scale systems.The thesis discusses whether sub-optimal search algorithms or methods of pre-simplifying a large-scale system are most suitable for dealing effectively and efficiently with the problem of deriving qualitative FIR models for them. The mask search space of FIR must be reduced in order to compute a model of a large-scale system in an affordable amount of time. To this aim, basically two lines of thought are given in the present dissertation. The first one is to directly simplify the candidate mask that is proposed to FIR. This can be done either directly, by reducing the number of input variables to the FIR model, or indirectly, using sub-optimal mask search algorithms. Two new sub-optimal mask search algorithms are proposed. The first method is another variant of a hill-climbing technique, which results in a high-quality mask while still converging in polynomial time. The second method is a new variant of a statistical approach that is based on spectral coherence functions.The second line of research in this dissertation is to obtain a decomposition of the system into subsystems. This would allow obtaining a model of the system from its subsystems, which in turn reduces the computational time needed for the overall effort. Given a k-variable system, the cost of computing a unique k-variable model is much higher than computing a set of p models of jp < k variables. With these complementary lines of work, two complete methodologies can be proposed, each of which enables the construction of qualitative models of complex systems. The former, based in simplifying the number of potential inputs to the FIR models, is an energy-based method, capable of detecting the variables at given delays that are more closely related to the considered output of the system. The latter proposes a decomposition of the overall system into subsystems. With the research presented in this thesis, the FIR modelling capabilities have been extended with capabilities for modelling large-scale systems within a reasonable time.

La navegació en entorns desconeguts no estructurats és encara un problema obert en el camp de la robòtica. En aquesta tesi presentem una aproximació per a la navegació de robots basada en la combinació de navegació basada en landmarks, representació fuzzy d'angles i distàncies i una coordinació multiagent basada en un mecanisme de dites. L'objectiu de la tesi ha sigut desenvolupar un sistema de navegació robust amb sentit de l'orientació per a entorns no estructurats usant informació visual.Per tal d'assolir aquest objectiu, hem centrat els nostres esforços en dues línies d'investigació: mètodes de navegació i construcció de mapes, i arquitectures de control per a robots autònoms.Pel que fa als mètodes de navegació i construcció de mapes, hem extès el treball presentat per Prescott per tal que es pugui utilitzar amb informació fuzzy sobre la localitazció dels landmarks. A part d'aquesta extensió, tambés hem desenvolupat mètodes per a calcular objectius alternatius, necessaris quan el robot troba el camí bloquejat.Pel que fa a l'arquitectura de control, hem proposat una arquitectura general que utilitza un mecanisme de dites per a coordinar un grup de sistemes que controlen el robot. Aquest mecanisme pot ser usat en diferents nivells de l'arquitectura. En el nostre cas l'hem usat per a coordinar els tres sistemes del robot (Navegació, Pilot i Visió), i tambés per a coordinar els agents que composen el sistema de Navegació. Usant aquest mecanisme de dites, l'acció que executa el robot és la més ben valorada en cada instant. D'aquesta manera, i si els agents fan les dites d'una manera racional, la dinàmica de les dites porta el robot a executar les accions necessàries per tal d'arribar a l'objectiu indicat. L'avantatge d'utilitzar aquest mecanisme és que no cal imposar una jerarquia entre els sistemes, com passa en l'arquitectura de subsumpció, si no que aquesta jerarquia canvia dinàmicament, depenent de la situació en què es troba el robot i les característiques de l'entorn.Hem obtingut resultats satisfactoris, tant en simulació com en experimentació amb un robot real, que confirmen que el sistema de navegació és capaç de construir un mapa d'un entorn desconegut i utlitzar-lo per a moure el robot d'una posició inicial a un objectiu donat. L'experimentació tambés ha mostrat que el sistema de coordinació basat en dites que hem dissenyat produeix el comportament global d'executar les accions necessàries en cada instant per tal d'arribar a l'objectiu. / Navigation in unknown unstructured environments is still a difficult open problem in the field of robotics. In this PhD thesis we present a novel approach for robot navigation based on the combination of landmark-based navigation, fuzzy distances and angles representation and multiagent coordination based on a bidding mechanism. The objective has been to have a robust navigation system with orientation sense for unstructured environments using visual information.To achieve such objective we have focused our efforts on two main threads: navigation and mapping methods, and control architectures for autonomous robots.Regarding the navigation and mapping task, we have extended the work presented by Prescott, so that it can be used with fuzzy information about the locations of landmarks in the environment. Together with this extension, we have also developed methods to compute diverting targets, needed by the robot when it gets blocked.Regarding the control architecture, we have proposed a general architecture that uses a bidding mechanism to coordinate a group of systems that control the robot. This mechanism can be used at different levels of the control architecture. In our case, we have used it to coordinate the three systems of the robot (Navigation, Pilot and Vision systems) and also to coordinate the agents that compose the Navigation system itself. Using this bidding mechanism the action actually being executed by the robot is the most valued one at each point in time, so, given that the agents bid rationally, the dynamics of the biddings would lead the robot to execute the necessary actions in order to reach a given target. The advantage of using such mechanism is that there is no need to create a hierarchy, such in the subsumption architecture, but it is dynamically changing depending on the specific situation of the robot and the characteristics of the environment.We have obtained successful results, both on simulation and on real experimentation, showing that the mapping system is capable of building a map of an unknown environment and use this information to move the robot from a starting point to a given target. The experimentation also showed that the bidding mechanism we designed for controlling the robot produces the overall behavior of executing the proper action at each moment in order to reach the target.

La propiedad de generalización de una máquina de aprendizaje, es decir su capacidad para emitir una respuesta correcta ante una nueva entrada semejante a aquellas con las que ha sido entrenada, es la característica principal que se busca en los sistemas conexionistas supervisados y sirve de justificación en la elección de los principios inductivos y el tipo de estructuras de aprendizaje para elaborar el presente estudio.La regularización o penalización es uno de estos principios que favorecen a nivel teórico la generalización, sobre el cual se ha desarrollado un método de cálculo directo de la matriz de regularización cuando se utiliza como estabilizador un operador diferencial de segundo grado, precisamente aquel que minimiza el grado de convexidad de la función solución, evitando así y el proceso iterativo de cálculo de la matriz hessiana y fijando el tipo de núcleo a ser utilizado.Los nexos de unión entre la regularización y el principio de minimización del riesgo estructural así como las excelentes características teóricas mostradas por este ´ ultimo principio trabajando, por definición, sobre conjuntos finitos de datos y expandiendo su solución sobre un número pequeño de núcleos, han llevado a desplazar el foco de trabajo de numerosos investigadoreshacia las máquinas de soporte vectorial, su materialización procedimental. En este contexto, se ha desarrollado una máquina que permite extender de forma natural el comportamiento binario de estas máquinas núcleo de margen máximo sobre problemas de clasificación hacia una solución ternaria m´asacorde con la estructura geométrica de los datos, en especial en las situaciones habituales de espacios de salida que poseen más de dos clases. El uso de la nueva arquitectura, bautizada K-SVCR,en problemas de multiclasificación resulta más adecuado que las reducciones estándares de problemas multiclase sobre máquinas biclasificadoras en estructuras en paralelo o arbóreas puesto que cada nodo de dicotomía considera todo el espacio de entrenamiento y se fuerza al hiperplano de separación a considerar la estructura geométrica de los patrones de entrenamiento. En especial, se demuestra la robustez del nuevo método ante fallos en las predicciones de algunos de sus nodos de trabajo cuando se considera un tipo especial de combinación de estas respuestas. La nueva arquitectura de multiclasificación ha sido modificada con posterioridad para ser implementada sobre un problema de clasificación con características independientes, la ordenación o problema de aprendizaje de preferencias. Sus prestaciones son evaluadas sobre una aplicación financiera en la determinación de riesgos crediticios. Finalmente, una aplicación de categorización o discriminación de escenarios de depuración donde incide el efecto de la temporalidad sirve también como ejemplo de funcionamiento. / The property of generalization of a learning machine, i.e. its capacity to emit a correct answer on a new similar input to those with wich it has been trained, is the basic behavior looked for in the supervised connexionists systems and it serves as justification in the selection of the inductive principles and the type of learning structures to ellaborate the present study.The penalty is one of these principles that favor at theoretical level the generalization, on which a method of direct calculation of the regularization matrix when a second degree differential operator is used like stabilizer, indeed that diminishing the convexity degree of the solution function, avoiding therefore the iterative process of calculation of the Hessian matrix, has been developed and fixing the type of kernel to be used. Links between regularization and the structural risk minimization principle as well as the excellent theoretical characteristics shown by this last principle working, by definition, on finite data sets and expanding their solution on a small number of kernels, have taken to move the center of study of numerous investigators towards the support vector machines, their procedural materialization. In this context, a machine that allows to extend of natural form the binary behavior of these maximum margin ker-nel machines on classification problems towards an agreed ternary solution with the geometric structure of the data has been developed, in special in the habitual situations of output spaces having more than two classes.The use of the new architecture, named K-SVCR, in multiclassification problems is more suitable than the standard reductions from multiclass problems on biclass machines in tree or parallel structures, since each di-chotomie node considers all the training space and force to the hyperplane of separation to consider the geometric structure of the training patterns.In special, the robustness of the new method is demostrated on failures in the predictions of some of its working nodes when a special type of combination of these answers is considered.The new architecture of multiclassification has been modified later to be implemented on a classification problem with independent characteristics, the ordenation or learning of preferences problem. Their benefits are evaluated on a financial application in the determination of credit risks. Finally, an application of categorization in waste water plant scenes, where the temporality affects, also serves like operation example.

ABRSTRACTThis thesis proposes YAM^2, a multidimensional conceptual model for OLAP(On-Line Analytical Processing). It is defined as an extension of UML (Unified Modeling Language). The aim is to benefit from Object-Oriented concepts and relationships to allow the definition of semantically rich multi-star schemas. Thus, the usage of Generalization, Association, Derivation, and Flow relationships (in UML terminology) is studied.An architecture based on different levels of schemas is proposed and the characteristics of its different levels defined. The benefits of this architecture are twofold. Firstly, it relates Federated Information Systems with Data Warehousing, so that advances in one area can also be used in the other. Moreover, the Data Mart schemas are defined so that they can be implemented on different Database Management Systems, while still offering a common integrated vision that allows to navigate through the different stars.The main concepts of any multidimensional model are facts and dimensions. Both are analyzed separately, based on the assumption that relationships between aggregation levels are part-whole (or composition) relationships. Thus, mereology axioms are used on that analysis to prove some properties.Besides structures, operations and integrity constraints are also defined for YAM^2. Due to the fact that, in this thesis, a data cube is defined as a function, operations (i.e. Drill-across, ChangeBase, Roll-up, Projection, and Selection) are defined over functions. Regarding the set of integrity constraints, they reflect the importance of summarizability (or aggregability) of measures, and pay special attention to it. / Esta tesis propone YAM^2, un modelo conceptual multidimensional para OLAP (On-Line Analytical Processing). Éste se define como una extensión de UML (Unified Modeling Language). La intención es beneficiarse de los conceptos y relaciones de la Orientación a Objetos para permitir la definición de esquemas multi-estrella semánticamente ricos. Así, se estudia la utilización de relaciones de tipo Generalization, Association, Derivation, y Flow (en terminología UML).Se propone también una arquitectura basada en diferentes niveles de esquemas, y se estudian las características de cada uno de esos niveles. De esta arquitectura se obtienen dos beneficios. Primeramente, relaciona los Sistemas de Información Federados con los Almacenes de Datos, de manera que los avances en una de las áreas se puedan utilizar en la otra. Además, los esquemas de los Almacenes de Datos Departamentales son definidos de forma que estos se pueden implementar sobre diferentes Sistemas de Gestión de Bases de Datos, al mismo tiempo que ofrecen una visión común e integrada, que permite navegar entre las diferentes estrellas.Los principales conceptos de cualquier modelo multidimensional son los hechos y las dimensiones. Ambos son estudiados de forma independiente, basado en la asunción de que las relaciones entre los niveles de agregación son de tipo parte-todo (o composición). Así, los axiomas de la mereología son utilizados en ese análisis para demostrar algunas propiedades.Juntamente con las estructuras, operaciones y restricciones de integridad son también definidas para YAM^2. Debido al hecho de que, en esta tesis, un cubo de datos es definido como una función, la operaciones (Drill-across, ChangeBase, Roll-up, Projection, y Selection) son definidas sobre funciones. Respecto al conjunto de restricciones de integridad, estas reflejan la importancia de la sumarizabilidad (o agregabilidad) de las medidas, y presta especial atención a ello. / Aquesta tesi proposa YAM^2, un model conceptual multidimensional per OLAP (On-Line Analytical Processing). El model es defineix com una extensió d'UML (Unified Modeling Language). La intenció és aprofitar conceptes i relacions de la Orientació a Objectes per permetre la definició d'esquemes multi-estrella semànticament rics. Així, s'estudia la utilització de relacions del tipus Generalization, Association, Derivation, i Flow (utilitzant la terminologia d'UML).Es proposa una arquitectura basada en diferents nivells d'esquemes i es defineixen les característiques dels nivells. Els beneficis d'aquesta arquitectura tenen dues vessants. Primerament, relaciona els Sistemes d'Informació Federats amb els Magatzems de Dades, de manera que els avenços en els primers es puguin utilitzar en els segons. A més, els Magatzems de Dades Departamentals es defineixen de manera que es puguin implementar en Sistemes Gestors de Bases de Dades diferents, al mateix temps que ofereixen una visió integrada que permet navegar a través de diferents estrelles.Els principals conceptes de qualsevol model multidimensionals són els fets i les dimensions. Ambdós són analitzats de forma separada, basat en l'assumpció que les relacions entre els nivells d'agregació són de tipus part-tot (o composició). Així, els axiomes de la mereologia són utilitzats en l'anàlisi per provar algunes propietats.Juntament amb les estructures, operacions i restriccions d'integritat han estat definides per YAM^2. Degut al fet que, en aquesta tesi, un cub de dades es definit com una funció, les operacions (Drill-across, ChangeBase, Roll-up, Projection, i Selection) són definides sobre funcions. Respecte al conjunt de restriccions d'integritat, aquestes reflecteixen la importància de la sumaritzabilitat (o agregabilitat) de les mesures, i paren especial atenció a ella.

Esta obra es una contribución al campo de la Complejidad de la Demostración, que estudia la complejidad de los sistemas de demostración en términos de los recursos necesarios para demostrar o refutar fórmulas proposicionales. La Complejidad de la Demostración es un interesante campo relacionado con otros campos de la Informática como la Complejidad Computacional o la Demostración Automática entre otros. Esta obra se centra en medidas de complejidad para sistemas de demostración refutacionales para fórmulas en FNC. Consideramos varios sistemas de demostración, concretamente Resolución, R(k) y Planos Secantes y nuestros resultados hacen referencia a las medidas de complejidad de tamaño y espacio.Mejoramos separaciones de tamaño anteriores entre las versiones generales y arbóreas de Resolución y Planos Secantes. Para hacerlo, extendemos una cota inferior de tamaño para circuitos monótonos booleanos de Ran y McKenzie a circuitos monótonos reales. Este tipo de separaciones es interesante porque algunos demostradores automáticos se basan en la versión arbórea de sistemas de demostración, por tanto la separación indica que no es siempre una buena idea restringirnos a la versión arbórea.Tras la reciente aparición de R(k), que es un sistema de demostración entre Resolución y Frege con profundidad acotada, era importante estudiar cuan potente es y su relación con otros sistemas de demostración. Resolvemos un problema abierto propuesto por Krajícek, concretamente mostramos que R(2) no tiene la propiedad de la interpolación monónota factible. Para hacerlo, mostramos que R(2) es estrictamente más potente que Resolución.Una pregunta natural es averiguar si se pueden separar sucesivos niveles de R(k) o R(k) arbóreo. Mostramos separaciones exponenciales entre niveles sucesivos de lo que podemos llamar la jerarquía R(k) arbórea. Esto significa que hay formulas que requieren refutaciones de tamaño exponencial en R(k) arbóreo, pero tienen refutaciones de tamaño polinómico en R(k+1) arbóreo. Propusimos una nueva definición de espacio para Resolución mejorando la anterior de Kleine-Büning y Lettmann. Dimos resultados generales sobre el espacio para Resolución y Resolución arbórea y también una caracterización combinatoria del espacio para Resolución arbórea usando un juego con dos adversarios para fórmulas en FNC. La caracterización permite demostrar cotas inferiores de espacio para la Resolución arbórea sin necesidad de usar el concepto de Resolución o Resolución arbórea. Durante mucho tiempo no se supo si el espacio para Resolución y Resolución arbórea coincidían o no. Hemos demostrado que no coinciden al haber dado la primera separación entre el espacio para Resolución y Resolución arbórea.También hemos estudiado el espacio para R(k). Demostramos que al igual que pasaba con el tamaño, R(k) arbóreo también forma una jerarquía respecto alespacio. Por tanto, hay fórmulas que necesitan espacio casi lineal en R(k) arbóreo mientras que tienen refutaciones en R(k+1) arbóreo con espacio contante. Extendemos todas las cotas inferiores de espacio para Resolución conocidas a R(k) de una forma sencilla y unificada, que también sirve para Resolución, usando el concepto de satisfactibilidad dinámica presentado en esta obra. / This work is a contribution to the field of Proof Complexity, which studies the complexity of proof systems in terms of the resources needed to prove or refute propositional formulas. Proof Complexity is an interesting field which has several connections to other fields of Computer Science like Computational Complexity or Automatic Theorem Proving among others. This work focuses in complexity measures for refutational proof systems for CNF formulas. We consider several proof systems, namely Resolution, R(k) and Cutting Planes and our results concern mainly to the size and space complexity measures. We improve previous size separations between treelike and general versions of Resolution and Cutting Planes. To do so we extend a size lower bound for monotone boolean circuits by Raz and McKenzie, to monotone real circuits. This kind of separations is interesting because some automated theorem provers rely on the treelike version of proof systems, so the separations show that is not always a good idea to restrict to the treelike version. After the recent apparition of R(k) which is a proof system lying between Resolution and bounded-depth Frege it was important to study how powerful it is and its relation with other proof systems. We solve an open problem posed by Krajícek, namely we show that R(2) does not have the feasible monotone interpolation property. To do so, we show that R(2) is strictly more powerful than Resolution. A natural question is to find out whether we can separate successive levels of R(k) or treelike R(k). We show exponential separations between successive levels of what we can call now the treelike R(k) hierarchy. That means that there are formulas that require exponential size treelike R(k) refutations whereas they have polynomial size treelike R(k+1) refutations. We have proposed a new definition for Resolution space improving a previous one from Kleine-Büning and Lettmann. We give general results for Resolution and treelike Resolution space and also a combinatorial characterization of treelike Resolution space via a Player-Adversary game over CNF formulas. The characterization allows to prove lower bounds for treelike Resolution space with no need to use the concept of Resolution or Resolution refutations at all. For a long time it was not known whether Resolution space and treelike Resolution space coincided or not. We have answered this question in the negative because we give the first space separation from Resolution to treelike Resolution. We have also studied space for R(k). We show that, as happened with respect to size, treelike R(k) forms a hierarchy respect to space. So, there are formulas that require nearly linear space for treelike R(k) whereas they have constant space treelike R(k+1) refutations. We extend all known Resolution space lower bounds to R(k) in an easier and unified way, that also holds for Resolution, using the concept of dynamical satisfiability introduced in this work.

In a commercial Internet, the traffic behavior is determined by the contracts between the ISPs and the users, where a user can be a dial-up user, or one corporate network or a group of individual customers or networks. Since the user is the entity with whom the contract is signed, it should also be the unit to which network resources are allocated. However, while much research in the past has been directed to fair resource allocations for flows (e.g. maxmin fairness and proportional fairness), much less effort has been invested on fair allocation of resources for users. The work done in this thesis tries to fill this gap: we study how to share fairly the network resources among users, when a user can possibly send several flows through different paths.The first part of the thesis focuses on the definition of a fairness criterion for the above problem: user maxmin fairness. The proposed criterion is based on the concepts of utility and welfare developed in the field of political science and political economics. We subdivide the problem of fairly allocating the network resources among users in two subproblems: 1) achieve fairness with respect to the utility experienced by the different users (inter-user fairness) and 2) achieve fairness with respect to the utility experienced by the different flows of a user (intra-user fairness). User maxmin fairness is the result of combining the two welfare functions that solve these two subproblems.Along with the user maxmin fairness criterion, in this thesis we propose a mechanism to implement it: the User Fair Queuing (UFQ) mechanism. In UFQ, a user is allowed to assign any label values to his packets to indicate their relative priority. At the ingress, an algorithm is used to control these labels assigned by the user. We have shown mathematically that: (a) the proposed label control does not allow the asymptotic throughput of a user to exceed its fair rate, and (b) if users label their packets in order to maximize their level of satisfaction or utility, then the resulting bandwidth allocation is user maxmin fair.In the last part of the thesis, we propose a network architecture for the Internet: the User Fair Differentiation (UFD) architecture. The UFD architecture extends the UFQ mechanism in such a way that its good features for resource sharing are preserved. In addition, UFD provides service differentiation, inter-domain communication, real-time traffic support and extensions for multicast and wireless. The fact that neither admission control nor signaling are required strongly contributes to the simplicity of UFD. The fact that no per-user state is kept at core nodes makes the proposed architecture scalable.The performance of the UFD architecture has been extensively evaluated via simulations and a prototype implementation. Both simulation and experimental results have validated the architecture proposed in this thesis.

Aquesta tesi presenta una nova metodologia per resoldre problemes de presa de decisions. Hemestudiat els casos en què cal considerar més d'un criteri. Aquests tipus de mètodes de decisió esconeixen com MCDM (Multiple Criteria Decision Making), o també MCDA (Multiple CriteriaDecision Aid). La diferència entre simplement "prendre decisions" o "ajudar a prendredecisions" recau en si el mètode es dissenya per recomanar la decisió a prendre o si tambéinclou elements que permeten entendre com es prenen les decisions en un cert context. La nostraproposta inclou elements dels dos plantejaments. D'una banda, hem intentat que la persona queha d'usar el mètode no necessiti aprendre tècniques complexes abans de poder-lo aplicar a casosreals. D'altra banda, el mètode no és una caixa negra, sinó que l'usuari rep informació sobrecaracterístiques de les dades que ha de tenir en compte abans de fer la decisió final.ClusDM és un mètode de presa de decisions pensat per resoldre dos tipus concrets deproblemes: (i) ordenar un conjunt d'alternatives de la millor a la pitjor, (ii) seleccionar lesmillors alternatives del conjunt. La dificultat d'aquest procés recau en que cal maximitzardiversos criteris parcials (i normalment no correlacionats) al mateix temps. A la tesi es pottrobar un resum de les diferents aproximacions a aquest tipus de problemes de decisió. Nomésdestacar que el nostre mètode segueix les bases de la Teoria de la Utilitat.Els mètodes clàssics consideren només criteris numèrics. Diferents extensions a aquests modelss'han anat desenvolupant durant els últims anys. En aquesta tesis ens hem plantejat lapossibilitat de tenir criteris que utilitzin diferents tipus de valors. A més, hem afegit dues fases ala metodologia habitual (que té una fase d'agregació i una d'ordenació), que són: l'explicaciódel resultat i l'avaluació de la qualitat.La "Fase d'explicació" està dedicada a assignar un terme lingüístic per descriure cadaalternativa segons la seva posició en el ranking. L'ús de vocabularis qualitatius facilita lacomprensió del resultat. El significat dels diferents termes usats ve donat per una funció denegació. Aquesta representació es basa en contrastar el significat d'un terme amb el dels termesoposats (els seus antònims).La "Fase d'Avaluació de la Qualitat" analitza a fons els resultats intermedis obtinguts en elsdiferents passos del procés i intenta mesurar l'error acumulat. ClusDM proporciona diversesmesures de qualitat parcial per cada fase del procés, de manera que l'usuari tingui constància dela confiança que pot donar al resultat final que doni el sistema. / This thesis presents a new methodology for decision making. In particular, we have studied theproblems that consider more than one criterion, which is known as Multiple Criteria DecisionMaking (MDCM) or Multiple Criteria Decision Aid (MCDA). The difference relies on the factof imitating the behaviour of the decision maker (i.e. develop a method that makes decisions) orgiving to the decision maker some additional information that allows him to understand themechanism of solving decisions (i.e. the decision maker can learn from the use of the method).Our proposal fits better in the MCDA approach, but has also similarities with the MCDMperspective. On one hand, the method we have designed is independent enough to not require adeep understanding of the process by the decision maker. On the other hand, we have carefullystudied the process and the method is able to extract knowledge about the decision problem,which is given to the user to let him know any special characteristics of the data analysed.ClusDM is a new method to solve multicriteria decision problems. It is able to find a ranking ofalternatives or to select the best ones. This process is not easy since usually it is not possible tomaximise all the partial profits (i.e.criteria) at the same time. In the thesis we present anoverview of the large amount of methods developed to solve this problem. We follow the utilitytheory approach.Classical methods consider only numerical criteria. Some extensions allow the consideration ofother scales, such as, fuzzy or ordinal values, but usually they are required to have a commonscale for all criteria. This thesis faces the problem of managing different types of criteria at thesame time. Methods following the utility approach consider two steps to sort a decisionproblem out: the aggregation and the ranking. We have included some additional steps in orderto improve the process: (i) the explanation phase and (ii) the quality measurement phase.In the "Explanation Phase", special attention is devoted to give an appropriate linguisticdescription of the ranking. The necessity to give a qualitatively described result has been arguedby different authors. The rationale behind this belief is that human decision makers understandbetter a linguistic statement characterising the selected alternative (or ranking of alternatives)than a numerical result or even a membership function. In this context, a new negation-basedsemantics has been studied. The key idea is that we can infer the meaning of a term knowing theterms that express an opposite value. The use of this new semantics representation seemsappropriate to obtain a result that can be easily understood by the decision maker.In the "Quality Measurement Phase", different quality measures for each stage of the processare calculated. With these measures we can give an overall value of the trustworthiness of thefinal result. This kind of information is very useful for the decision maker in order to pay moreor less attention to the recommendations of the system.

Liu Ch'i, a belletrist of the Chin dynasty (1115-1234), recorded an eyewitness account of the fall of the Chin in his memoir, the Kuei-ch'ien-chih (The Record of One Returned to Obscurity). He was motivated by an inner logic which thematically argues that: The disintegration of effective Chin administration was a direct result of the deterioration of Chin literary standards, symptomatic of a more basic degeneration of the traditional Confucian high culture. The collapse of the Chin climaxed approximately three hundred years of rise and fall (c. 900-1234). As Jurchen tribal organization became inadequate, they imitated the Ch'i-tan model of a dualistic tribal-agrarian society and tended to adopt Chinese institutions. Dynamic decline seemed in direct proportion to the decline in Jurchen institutions. However, Liu Ch'i observed this decline and its climax in the fall of the Chin capital, K'aifeng, and thought that the Chin failed for not fully adopting Chinese ones. His memoir, Kuei-ch'ien-chih, was transmitted from its writing in 1235 to the present edition, the Chung-hua shu-chu Yuan-Ming shi-k'o pi-cho ts'ung-k'an, collated by Ts'ui Wen-yin (second edition 1983). Liu Ch'i illustrates his themes with Chin pesonalities portraying the union of ability-aspiration-achievement to mean the highest combination of traditional Confucian values. He quickly attentuates this theme in the succeeding chuan to show possible variations of failure in a descending taxonomy. In his seventh chuan, Liu Ch'i argues that since the Chin dynasty limited their literary focus of the civil service examinations solely upon the lyric, the prose-poem, and the commentary on the classics, the source of potential leadership, the chin-shih, became intellectually effete leasing to a degeneration in political dynamics. Liu Ch'i's personal rationalization was one of confident expectation despite an involvement in drafting a testimonial to Ts'ui Li, who had betrayed K'aifeng to the Mongols. He felt that time and circumstance were cyclical in nature and that he had fulfilled his destiny and his duty. Liu Ch'i's memoir warrants a closer examination in its entirety to appreciate its inner, thematic logic and a translation of the preface and first three chapters is presented as a preliminary to the full translation.

de la tesi doctoralL'objectiu principal del treball realitzat ha sigut el desenvolupar una manera de modelar el procés d'investigació racional (l'evolució de les creences d'un agent racional com a conseqüència de la seva interacció amb l'entorn i dels seus procesos d'inferència), mantenint la idea general del model dels móns possibles i la semàntica de Kripke, però intentant evitar els problemes de l'omnisciència lògica i el raonament ideal. Les contribucions principals del treball són:· S'ha fet un estudi molt detallat sobre les diferents propostes que s'han fet en el tema del tractament formal del problema de l'omnisciència lògica en les lògiques modals de creences. Aquest estudi ressalta les semblances i diferències entre les diverses solucions i mostra fins a quin punt solucionen el problema del raonament ideal.· Com a resultat d'aquest estudi, es suggereix una nova aproximació al problema, basada en el concepte dels móns impossibles. La idea principal és que una situació pot ser percebuda de diferents maneres per diferents agents; així, una situació pot ser descrita de forma subjectiva per cadascun d'ells. A més, en cada situació un agent pot tenir raons per recolzar i/o rebutjar determinats fets. La percepció que un agent té del seu entorn determina les seves creences en aquella situació. Aquestes són les idees bàsiques del concepte de situacions subjectives proposat a la tesi.· S'ha determinat quines són les activitats bàsiques que poden modificar les creences d'un agent racional (realització de deduccions, plantejament de dubtes, plantejament de preguntes a l'entorn i rebuda de dades externes). També s'ha definit una classe específica d'agents racionals, els investigadors racionals, que realitzen aquestes activitats d'una forma concreta (manipulant fórmules de primer ordre en un arbre de taulers analítics).· Per últim, a la tesi es mostra com l'evolució de les creences dels investigadors racionals, causada per la seva anàlisi dinàmica multi-dimensional, pot ser modelitzada formalment dins del marc de les situacions subjectives. Això es fa utilitzant les situacions concebibles, que corresponen a aquells escenaris que l'agent pot considerar, independenment de la seva possible parcialitat o inconsistència. L'evolució de les creences d'un agent es modelitza amb la generació d'una seqüència de relacions d'accessibilitat, en la que, després de cada pas d'anàlisi de les creences, van canviant les situacions concebibles considerades com a alternatives viables per l'agent. / of the PhD thesisThe main aim of this work has been to develop a way to model the process of rational inquiry (the evolution of a rational agent's set of beliefs over time as a consequence of its interaction with the world and its internal inferential processes), keeping the general idea of the possible worlds model and the Kripke semantics but trying to avoid the problems of logical omniscience and perfect reasoning. The actual contributions of the work described in the thesis are the following:· An extensive survey of the state of the art has been made, in which the most relevant approaches that have been proposed to solve the problems of logical omniscience and perfect reasoning are presented. This review focuses on the similarities and differences between the various solutions and shows to which degree they provide a framework in which it is possible to model non-ideal reasoners.· As a result of this study, an impossible-worlds based framework in which logical omniscience is avoided is suggested. The main idea of this proposal is that a situation may be perceived in different ways by different agents; thus, a situation may be described subjectively by each of them. Furthermore, in each situation an agent may have reasons to suport and/or reject certain facts. The perception that an agent has of a situation will determine its beliefs in that situation. These are the basic ideas underlying the subjective situations described in the dissertation.· It has been determined which are the basic activities that may modify the set of beliefs of a rational agents (performing deductions, posing doubts, making questions to the environment and receiving external data). A specific class of rational agents, called rational inquirers, is also defined. These agents perform their doxastic activities in a concrete way, which is based in the manipulation of first-order formulae contained in an analytic tableaux tree. · Finally, in the dissertation it is shown how the evolution of the beliefs of the rational inquirers, caused by their dynamic multi-dimensional analysis, may be formally modelled in the subjective situations framework. This modelling is performed using conceivable situations, which correspond to those scenarios that may be considered by the modelled agent, irrespective of their possible partiality or inconsistency. The evolution of the beliefs of an agent is modelled with the generation of a sequence of accessibility relations in which, after each step of belief analysis, the situations that are considered as viable by the agent change in an appropriate way.

Les contribucions d'aquesta tesi uneixen dues disciplines: ciències ambientals (específicament, gestió d'aigües residuals) i informàtica (específicament, intel·ligència artificial). El tractament d'aigües residuals com a disciplina opera fent servir un rang de diferents enfocaments i mètodes que inclouen: control manual, control automàtic on-line, modelat numèric o no-numèric, models estadístics i simulacions. La tesi caracteritza la recerca interdisciplinària de tècniques d'intel·ligència artificial (raonament basat en regles, raonament basat en casos, ontologies i planificació) a sistemes de suport a la decisió a l'entorn ambiental. El disseny de l'arquitectura d'aquesta aplicació, el sistema OntoWEDSS, augmenta els sistemes clàsics de raonament existents (raonament basat en regles i basat en casos) amb una ontologia de domini per a la gestió de plantes de tractament d'aigües residuals. La integració de l'ontologia WaWO recentment creada proporciona a OntoWEDSS una major flexibilitat en la capacitat de gestió. La construcció del sistema de suport a la decisió OntoWEDSS es basa en l'estudi d'un cas específic, però el sistema també és d'interès general ja que l'arquitectura basada en l'ontologia pot aplicar-se a qualsevol estació depuradora i, a un nivell apropiat d'abstracció, a altres dominis ambientals. El sistema OntoWEDSS millora la diagnosi de l'estat de l'estació depuradora, proporciona suport a la solució de complexes problemes relacionats amb aigües residuals, i facilita el modelatge del coneixement i la seva reutilització mitjançant l'ontologia WaWO. En particular, a la investigació s'han aconseguit els següents objectius: (1) la millora del modelatge de la informació sobre processos de tractament d'aigües residuals i la clarificació de part de la confusió existent en la terminologia del domini, (2) la incorporació de coneixement microbiològic (referent al procés del tractament i modelat mitjançant una ontologia) dins del procés de raonament, (3) la creació d'un sistema de suport a la decisió amb tres nivells (percepció, diagnosi i suport a la decisió) que combina coneixement mitjançant una nova integració entre KBSs i ontologies, proporcionant millors resultats, (4) la eliminació d'obstacles existents en el raonament, obtinguda utilitzant el nou coneixement microbiològic codificat a l'estructura jeràrquica i a les relacions de l'ontologia, (5) la representació de relacions causa-efecte, degut a la implementació d'un conjunt de relacions que permeten a l'ontologia deduir automàticament la resposta a qüestions sobre el domini d'aigües residuals. OntoWEDSS està implementada en el llenguatge de programació LISP, fent servir el software Allegro Common LISP. S'ha dut a terme una avaluació focalitzada del sistema, basada en la valoració de la capacitat de resposta a situacions problemàtiques específiques, obtenint-se bons resultats. / Las contribuciones de esta tesis unen dos disciplinas: ciencias ambientales (específicamente, gestión de aguas residuales) e informática (específicamente, inteligencia artificial). El tratamiento de aguas residuales como disciplina opera utilizando un rango de diferentes enfoques y métodos que incluye: control automático on-line, modelado numérico o no-numérico, razonamiento basado en reglas, razonamiento basado en casos, soporte a la decisión y planificación. La tesis caracteriza una aplicación interdisciplinaria de técnicas de inteligencia artificial a sistemas de soporte a la decisión en el dominio ambiental. El diseño de la arquitectura de esta aplicación, el sistema OntoWEDSS, aumenta los sistemas híbridos de razonamiento ya existentes (razonamiento basado en reglas y basado en casos) con una ontología de dominio para la gestión de plantas de tratamiento de aguas residuales. La integración de la ontología WaWO, de nueva creación, proporciona a OntoWEDSS una mayor flexibilidad en la capacidad de gestión. La construcción del sistema de soporte a la decisión OntoWEDSS se basa en el estudio de un caso específico, pero el sistema resulta también es de interés general puesto que la arquitectura basada en ontologías puede aplicarse a cualquier planta de tratamiento de aguas residuales y, a un nivel apropiado de abstracción, a otros dominios ambientales. El sistema OntoWEDSS mejora la diagnosis del estado de la planta de tratamiento, proporciona soporte a la resolución de complejos problemas relacionados con aguas residuales, y facilita el modelado del conocimiento y su reutilización mediante la ontología WaWO. En particular, la investigación ha alcanzado los siguientes objetivos: (1) la mejora del modelado de la información sobre procesos de tratamiento de aguas residuales y la clarificación de parte de la confusión existente en la terminología relacionada, (2) la incorporación de conocimiento microbiológico (referente al proceso del tratamiento y modelado mediante una ontología) dentro del proceso de razonamiento, (3) la creación de un sistema de soporte a la decisión con tres estratos (percepción, diagnosis y soporte a la decisión) que combina conocimiento mediante una novedosa integración entre KBSs y ontologías, proporcionando mejores resultados, (4) la eliminación de obstáculos existentes en el razonamiento, hallada utilizando el nuevo conocimiento microbiológico codificado en la estructura jerárquica y las relaciones de la ontología, (5) la representación de relaciones causa-efecto, debido a la implementación de un conjunto de relaciones que permiten a la ontología deducir automáticamente la respuesta a cuestiones sobre el dominio de aguas residuales. OntoWEDSS está implementada en el lenguaje de programación LISP, usando el software Allegro Common LISP. Se ha llevado a cabo una evaluación enfocada del sistema, basada en la valoración de la capacidad de respuesta a situaciones problemáticas específicas, obteniéndose buenos resultados. / The contributions of this thesis bridge two disciplines: environmental science (specifically, wastewater management) and computer science (specifically, artificial intelligence). Wastewater management as a discipline operates using a range of different approaches and methods which include: manual control, on-line automatic control, numerical or non-numerical models, statistical models and simulation models. The thesis characterizes an interdisciplinary research on artificial intelligence techniques (rule-based reasoning, case-based reasoning, ontologies and planning) applied to environmental decision-support systems. The integrated architecture's design of this application, the OntoWEDSS system, augments classic reasoning systems (rule-based reasoning and case-based reasoning) with a domain ontology about the management of wastewater treatment plants. The integration of the newly created WaWO ontology provides a more flexible management capability to OntoWEDSS. The construction of the OntoWEDSS decision support system is based on a specific case study but the system is also of general interest, given that its ontology-underpinned architecture can be applied to any wastewater treatment plant and, at an appropriate level of abstraction, to other environmental domains. The OntoWEDSS system improves the diagnosis of the state of a treatment plant, provides support for wastewater-related complex problem-solving, and facilitates knowledge modeling and reuse by means of the WaWO ontology. The following research targets have been achieved in particular: (1) the improvement of the modeling of the information about wastewater treatment processes and the clarification of a part of the existing terminological confusion in the domain, (2) the incorporation of ontology-modeled microbiological knowledge related to the treatment process into the reasoning process, (3) the creation of a decision support system with three layers (perception, diagnosis and decision support) which combines knowledge through a novel integration between KBSs and ontologies, providing better results, (4) the solution of existing reasoning-impasses, found using the new microbiological knowledge encoded in the hierarchical structure and the relations of the ontology, (5) the representation of cause-effect relations, due to the implementation of a set of relations that enable the ontology to automatically deduce the answer to questions about the wastewater domain. OntoWEDSS is implemented in the LISP programming language, using Allegro Common LISP software. A focused evaluation of the system, founded on the assessment of the capacity of response to specific problematic situations, has been carried out and has given fine results. / Questa tesi contribuisce alla intersezione di due discipline: le scienze ambientali (specificamente, la gestione delle acque di rifiuto) e la informatica (specificamente, la intelligenza artificiale). Nel trattamento delle acque di rifiuto come disciplina si utilizzano diversi metodi, che includono: controllo manuale, controllo automatico on-line, modelli numerici o non-numerici e simulazioni. La tesi caratterizza un'applicazione interdisciplinare di tecniche di intelligenza artificiale a sistemi di aiuto alla decisione in campo ambientale. L'architettura di questa applicazione, il sistema OntoWEDSS, amplia i sistemi di ragionamento ibrido esistenti (ragionamento basato su un sistema di regole, ragionamento basato sull'esperienza, aiuto alla decisione e pianificazione) con un'ontologia di dominio per la gestione di depuratori di acque di rifiuto. L'integrazione dell'ontologia WaWO, di nuova creazione, fornisce a OntoWEDSS una maggiore flessibilità nella sua capacità di gestione. La costruzione del sistema OntoWEDSS si basa sullo studio di un caso specifico, però il sistema risulta anche di interesse generale dato che l'architettura basata su un'ontologia può essere applicata a un qualsiasi depuratore e, considerando un adeguato livello d'astrazione, ad altri domini ambientali. Il sistema OntoWEDSS migliora la diagnosi dello stato del depuratore, fornisce aiuto alla soluzione di problemi complessi relazionati con le acque di rifiuto e facilita la modellizzazione della conoscenza e la sua riutilizzazione mediante l'ontologia WaWO. In particolare, la ricerca realizzata ha raggiunto i seguenti obiettivi: (1) il miglioramento dell'informazione sui processi di depurazione e il chiarimento di parte della confusione esistente nella terminologia relativa, (2) l'incorporazione di conoscenza microbiologica (riguardo al processo di depurazione e mediante la modellizzazione ontologica) nel processo di ragionamento, (3) la creazione di un sistema di aiuto alla decisione con tre livelli (percezione, diagnosi e aiuto alla decisione) che combina la informazione mediante un nuovo tipo d'integrazione tra classici sistemi basati sulla conoscenza e ontologie, proporzionando risultati migliori, (4) l'eliminazione di alcuni ostacoli esistenti nel ragionamento, ottenuta utilizzando la nuova conoscenza microbiologica codificata nella struttura gerarchica e nelle relazioni dell'ontologia, (5) la rappresentazione di relazioni causa-effetto del mondo reale attraverso l'implementazione di un insieme di relazioni ontologiche che permettono di dedurre automaticamente le risposte a domande sul dominio delle acque di rifiuto. OntoWEDSS è implementata nel linguaggio di programmazione LISP, usando il software Allegro Common LISP. È stata realizzata una valutazione del sistema basata sulla stima della capacità di risposta a situazioni problematiche specifiche e si sono ottenuti risultati soddisfacenti.