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This thesis presents a framework for inter-agent communication, represented and partially implemented with default reasoning. I focus on the limited goal of determining the meaning for a Hearer-agent of an utterance ω by a Speaker-agent, in terms of the beliefs of the interlocutors. This meaning is generally more than just the explicit propositional contents of ω, and more than just the Speaker's goal to convey her belief that ω. One way of determining this meaning is to let the Hearer take stock of the implicit components of the Speaker's utterances. Among the implicit components of the meaning of ω, I show in particular how to derive certain of its presuppositions with a set of default schemata using a framework for default reasoning. More information can be extracted from the communications channel between interlocutors by adopting a normative model of inter-agent communication, and using this model to explain or 'make sense' of the Speaker's utterances. I construct such a model expressed in terms of a set of default principles of communication using the same framework for default reasoning. The task of deriving the meaning of an utterance is similar to the job required of a user-interface, where the user is the Speaker-agent, and the interface itself is the Hearer-agent. The goal of a user-interface as Hearer is to make maximal use of the data moving along the communications channel between user and application. The result is an integrated theory of normative, inter-agent communications expressed within an ontologically and logically minimal framework. This work demonstrates the development and application of a methodology for the use of default reasoning. The implementation of the theory is also presented, along with a discussion of its applicability to practical user-interfacing. A view emerges of user-modelling as a component of a user-interface. / Science, Faculty of / Computer Science, Department of / Graduate

Orientador: Itala Maria Loffredo D'Ottaviano / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Filosofia e Ciências Humanas / Made available in DSpace on 2018-08-22T15:04:13Z (GMT). No. of bitstreams: 1 Almeida_EdgarLuisBezerrade_M.pdf: 946200 bytes, checksum: e8e316a3ee7420c8d7f45a751651a436 (MD5) Previous issue date: 2013 / Resumo: Esta Dissertação apresenta uma definição de lógica abstrata e caracteriza alguns sistemas lógicos bastante conhecidos na literatura como casos particulares desta. Em especial, mostramos que a lógica de primeira ordem, lógica de segunda ordem, lógica com o operador Q1 de Mostowski e a lógica infinitária L!1! são casos particulares de lógicas abstratas. Mais que isso, mostramos que tais lógicas são regulares. Na análise de cada uma das lógicas acima citadas, mostramos o comportamento das mesmas com relação às propriedades de Löwenheim-Skolem e compacidade enumerável, resultados estes centrais à teoria de modelos. Nossa análise permite-nos constatar que, dentre os quatro casos apresentados, o único que goza de ambas as propriedades é a lógica de primeira ordem; as demais falham em uma, na outra ou em ambas as propriedades. Mostramos que isso não é mera coincidência, mas sim um resultado profundo, que estabelece fronteiras bem delimitadas à lógica de primeira ordem, conhecido como primeiro teorema de Lindström: se uma lógica é regular, ao menos tão expressiva quanto à lógica de primeira ordem e satisfaz ambas as propriedades citadas, então esta é equivalente a lógica de primeira ordem. Realizamos uma prova cuidadosa do teorema, em que cada ideia e cada estratégia de prova é estabelecida criteriosamente. Com seu trabalho, Lindström inaugurou um novo e profícuo campo de estudo, a teoria abstrata de modelos que estabelece, com relação a diversas combinações de propriedades de sistemas lógicos, uma estratificação entre lógicas. Apresentamos um outro exemplo de tal estratificação através de uma versão modal do teorema de Lindström, versão esta que caracteriza a lógica modal básica como maximal quanto a bissimilaridade e compacidade. Encerramos esta Dissertação com algumas considerações acerca da influência do primeiro teorema de Lindström / Abstract: This thesis presents the definition of abstract logic and features some quite logical systems presented in the literature as particular cases of this. In particular, we show that first-order logic, second-order logic, the logic with Mostowski's operator Q1 and the infinitary logic L!1! are specific systems of abstract logic. Moreover, we show that such logics are regular. In the analysis of each above mentioned logical systems we analyses his performance with regard to the properties of compactness and Löwenheim-Skolem, results that have important role in model theory. Our analysis allows us to conclude that among the four cases, the only one who enjoys both properties is the first-order logic, and all others fail in one, other or both properties. We show that this is not mere coincidence, but rather a deep, well-defined boundaries establishing the first-order logic, known as first Lindström's theorem: a regular logic that is at least as expressive as first-order logic and satisfies both properties mentioned, then this is equivalent to first-order logic. We conducted a thorough proof of the theorem, in which each idea and each proof strategy is carefully established. With his work Lindström inaugurated a new and fruitful field of study, the abstract model theory, which establishes with respect to different combinations of properties of logical systems, stratification between logical. Here is another example of such stratification through one of the theorem of modal version Lindström, which characterizes this version of the logic basic modal such as maximal bissimimulation and compactness. We conclude the thesis with some considerations about the influence of the Lindström's theorem / Mestrado / Filosofia / Mestre em Filosofia

L'ingénierie des systèmes complexes et systèmes de systèmes conduit souvent à des activités de modélisation (MA) complexes. Les problèmes soulevés par les MA sont notamment : comprendre le contexte dans lequel elles sont exécutées, comprendre l'impact sur les cycles de vie des modèles qu'elles produisent, et finalement trouver une approche pour les maîtriser. L'objectif principal de cette thèse est d'élaborer une approche formelle pour adresser ce problème. Dans cette thèse, après avoir étudié les travaux connexes en ingénierie système et plus spécifiquement ceux qui portent sur la co-ingénierie du système à faire (le produit) et du système pour faire (le projet), nous développons une méthodologie nommée MODEF pour traiter ce problème. MODEF consiste en: (1) Caractériser les MA comme un système et plus généralement une fédération de systèmes. (2) Construire de manière itérative une architecture de ce système via la modélisation du contenu conceptuel des modèles produits par MA et leur cycle de vie, les tâches réalisées au sein des MA et leurs effets sur ces cycles de vie. (3) Spécifier les attentes sur ces cycles de vie. (4) Analyser les modèles (des MA) par rapport à ces attentes (et éventuellement les contraintes sur les tâches) pour vérifier jusqu'à quel point elles sont atteignables via la synthèse des points (ou états) acceptables. D'un point de vue pratique, l'exploitation des résultats de l'analyse permet de contrôler le déroulement des tâches de modélisation à partir de la mise en évidence de leur impact sur les modèles qu'elles produisent. En effet, cette exploitation fournit des données pertinentes sur la façon dont les MA se déroulent et se dérouleraient de bout en bout. A partir de ces informations, il est possible de prendre des mesures préventives ou correctives. Nous illustrons cela à l'aide de deux cas d'étude (le fonctionnement d'un supermarché et la modélisation de la couverture fonctionnelle d'un système). D'un point de vue théorique, les sémantiques formelles des modèles des MA et le formalisme des attentes sont d'abord données. Ensuite, les algorithmes d'analyse et d'exploitation sont présentés. Cette approche est brièvement comparée avec des approches de vérification des modèles et de synthèse de systèmes. Enfin, deux facilitateurs de la mise en œuvre de MODEF sont présentés. Le premier est une implémentation modulaire des blocs de base de MODEF. Le second est une architecture fédérée (FA) des modèles visant à faciliter la réutilisation des modèles formels en pratique. La formalisation de FA est faite dans le cadre de la théorie des catégories. De ce fait, afin de construire un lien entre abstraction et implémentation, des structures de données et algorithmes de base sont proposés pour utiliser FA en pratique. Différentes perspectives sur les composantes de MODEF concluent ce travail. / The engineering of complex systems and systems of systems often leads to complex modelling activities (MA). Some challenges exhibited by MA are: understanding the context where they are carried out and their impacts on the lifecycles of models they produce, and ultimately providing a support for mastering them. How to address these challenges with a formal approach is the central challenge of this thesis. In this thesis, after discussing the related works from systems engineering in general and the co-engineering of the system to be made (product) and the system for make (project) systems specifically, we position and develop a methodology named MODEF, that aims to master the operation of MA. MODEF consists in: (1) characterizing MA as a system (and more globally as a federation of systems) in its own right; (2) iteratively architecting this system through: the modelling of the conceptual content of the models produced by MA and their life cycles, the tasks carried out within MA and their effects on these life cycles; (3) specifying the expectations over these life cycles and; (4) analysing models (of MA) against expectations (and possibly tasks constraints) - to check how far expectations are achievable - via the synthesis of the acceptable behaviours. On a practical perspective, the exploitation of the results of the analysis allows figuring out what could happen with the modelling tasks and their impacts on the whole state of models they handle. We show on two case studies (the operation of a supermarket and the modelling of the functional coverage of a system) how this exploitation provides insightful data on how the system is end-to-end operated and how it can behave. Based on this information, it is possible to take some preventive or corrective actions on how the MA are carried out. On the foundational perspective, the formal semantics of three kinds of involved models and the expectations formalism are first discussed. Then the analysis and exploitation algorithms are presented. Finally this approach is roughly compared with model checking and systems synthesis approaches. Last but not least, two enablers whose first objectives are to ease the implementation of MODEF are presented. The first one is a modular implementation of MODEF's buildings blocks. The second one is a federated architecture (FA) of models which aims to ease working with formal models in practice. Despite the fact that FA is formalised within the abstract framework of category theory, an attempt to bridge the gap between abstraction and implementation is sketched via some basic data structures and base algorithms. Several perspectives related to the different components of MODEF conclude this work.