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High-level action programming languages such as Golog have successfully been used to model the behavior of autonomous agents. In addition to a logic-based action formalism for describing the environment and the effects of basic actions, they enable the construction of complex actions using typical programming language constructs. To ensure that the execution of such complex actions leads to the desired behavior of the agent, one needs to specify the required properties in a formal way, and then verify that these requirements are met by any execution of the program. Due to the expressiveness of the action formalism underlying Golog (situation calculus), the verification problem for Golog programs is in general undecidable. Action formalisms based on Description Logic (DL) try to achieve decidability of inference problems such as the projection problem by restricting the expressiveness of the underlying base logic. However, until now these formalisms have not been used within Golog programs. In the present paper, we introduce a variant of Golog where basic actions are defined using such a DL-based formalism, and show that the verification problem for such programs is decidable. This improves on our previous work on verifying properties of infinite sequences of DL actions in that it considers (finite and infinite) sequences of DL actions that correspond to (terminating and non-terminating) runs of a Golog program rather than just infinite sequences accepted by a Büchi automaton abstracting the program.

Golog is a high-level action programming language for controlling autonomous agents such as mobile robots. It is defined on top of a logic-based action theory expressed in the Situation Calculus. Before a program is deployed onto an actual robot and executed in the physical world, it is desirable, if not crucial, to verify that it meets certain requirements (typically expressed through temporal formulas) and thus indeed exhibits the desired behaviour. However, due to the high (first-order) expressiveness of the language, the corresponding verification problem is in general undecidable. In this paper, we extend earlier results to identify a large, non-trivial fragment of the formalism where verification is decidable. In particular, we consider properties expressed in a first-order variant of the branching-time temporal logic CTL*. Decidability is obtained by (1) resorting to the decidable first-order fragment C² as underlying base logic, (2) using a fragment of Golog with ground actions only, and (3) requiring the action theory to only admit local effects. / In this extended version we extend the decidability result for the verification problem to the temporal logic CTL* over C2-axioms.

Dans le but d’optimiser la représentation en mémoire des enregistrements Scheme dans le compilateur Gambit, nous avons introduit dans celui-ci un système d’annotations de type et des vecteurs contenant une représentation abrégée des enregistrements. Ces derniers omettent la référence vers le descripteur de type et l’entête habituellement présents sur chaque enregistrement et utilisent plutôt un arbre de typage couvrant toute la mémoire pour retrouver le vecteur contenant une référence. L’implémentation de ces nouvelles fonctionnalités se fait par le biais de changements au runtime de Gambit. Nous introduisons de nouvelles primitives au langage et modifions l’architecture existante pour gérer correctement les nouveaux types de données. On doit modifier le garbage collector pour prendre en compte des enregistrements contenants des valeurs hétérogènes à alignements irréguliers, et l’existence de références contenues dans d’autres objets. La gestion de l’arbre de typage doit aussi être faite automatiquement. Nous conduisons ensuite une série de tests de performance visant à déterminer si des gains sont possibles avec ces nouvelles primitives. On constate une amélioration majeure de performance au niveau de l’allocation et du comportement du gc pour les enregistrements typés de grande taille et des vecteurs d’enregistrements typés ou non. De légers surcoûts sont toutefois encourus lors des accès aux champs et, dans le cas des vecteurs d’enregistrements, au descripteur de type. / In order to optimize the in memory representation of Scheme records in the Gambit compiler, we introduce a type annotation system on record fields. We also introduce flat vector of records containing an abbreviated representation of those records. These vectors omit the header and reference to the type descriptor on contained records and use a type tree spanning the whole memory to recover the type as needed from an internal pointer. The implementation of the new functionnalities is done through changes in the Gambit runtime. We add new primitives to the language and modify the existing architecture to correctly handle the new data types in a way transparent that is transparent to the user. To do so, we modify the garbage collector to account to account for the existance of internal references and of heterogenous records whose fields may not be alligned to a word and need not be boxed. We also have to automatically and systematically update hte type tree to reflect the live vectors. To asses our implementation’s performance, we run a serie of benchmarks. We measure significant gains on allocation time and space with both typed records and contained records. We also measure a minor overhead in access costs on typed fields and major loss on accesses to the type descriptor of contained records.

A Engenharia de Software tem desenvolvido técnicas e métodos para apoiar o desenvolvimento de software confiável, flexível, com baixo custo de desenvolvimento e fácil manutenção. A avaliação da manutenibilidade contribui para fornecer meios para produzir software com alta qualidade. Este trabalho apresenta um experimento controlado para avaliar a manutenibilidade entre as abordagens de web services: RESTful e SOAP-WSDL. Esta avaliação foi conduzida usando 3 programas implementados na linguagem de programação Java e com a mesma arquitetura. Com base na arquitetura projetada, os web services desenvolvidos foram utilizados como objetos em estudos de caso, possibilitando avaliar e comparar a sua manutenibilidade. Os resultados obtidos demonstraram relações entre as informações sobre o custo e a qualidade dos serviços web, que contribuíram para esclarecer os critérios para a obtenção de uma boa relação entre o custo da manutenção e a evolução dos serviços web. Para concluir, os resultados indica que os web services RESTful são mais manuteníveis do lado do servidor, e os web services SOAP-WSDL são mais manuteníveis do lado do cliente. Os estudos realizados no experimento controlado são promissores e podem auxiliar na redução de custo na manutenção dos serviços web, melhorando dessa forma a qualidade do software no geral / Software Engineering has developed techniques and methods to support the development of reliable software, exible, low development cost and easy maintenance. The evaluation of maintainability contributes in this direction, providing the means to produce software with high quality. This paper presents an controlled experiment to evaluate the maintainability between the approaches of web services: RESTful and SOAP-WSDL. This evaluation was conducted using four programs implemented in the Java programming language, using the same architecture. Based on the designed architecture, Web services were developed as objects used in case studies, allowing to evaluate and compare its maintainability. The results showed relationships between the information on the cost and quality of web services, which contributed to clarify the criteria for obtaining a good relationship between the cost of maintenance and evolution of web services. In conclusion, the results indicate the RESTful web services are more maintainable server side in contrast to the SOAP-WSDL web services are more maintainable client side. Studies in controlled experiments are promising and may help reduce the maintenance cost of web services, thus improving overall software quality

La plupart des processus informatiques mettent en jeu la notion de transformation, en particulier la compilation. Nous nous intéressons dans cette thèse à fournir des outils et des méthodes, utilisant la réécriture, permettant d'accroître la confiance que l'on peut placer dans ces processus. Nous développons dans un premier temps un cadre permettant de valider la compilation de constructions de filtrage, produisant une preuve formelle de la validité de la compilation, ainsi qu'un témoin de cette preuve, à chaque exécution du compilateur. Afin de permettre l'écriture sûre de transformations complexes, nous proposons un générateur de structures de données efficaces intégrant des invariants algébriques, et un langage de stratégies permettant de contrôler l'application des transformations. Ces résultats constituent donc une avancée vers la constitution de methodes génériques sûres pour le développement de transformations de confiance. / Most computer processes involve the notion of transformation, in particular the compilation processes. We interest in this thesis in providing tools and methods, based on rewriting, giving the opportunity to increase the confidence we can place into those processes. We develop first a framework used to validate the compilation of matching constructs, building a formal proof of the validity of the compilation process along with a witness of this proof, for each run of the compiler. Then, in order to allow one to write safely complex transformations, we propose a tool that generates an efficient data structure integrating algebraic invariants, as well as a strategy language that enables to control the application of transformations. Those results can be seen as a first step towards the constitution of generic and safe methods for the development of trustworthy transformations.

Simulationssprachen sind in Bezug auf die Unterstützung neuer domänenspezifischer Konzepte mit einer dem Problem entsprechenden prägnanten Darstellung nicht flexibel erweiterbar. Dies betrifft sowohl die Sprache in ihren Konzepten als auch die Unterstützung der Sprache durch Sprachwerkzeuge. In dieser Arbeit entsteht der neue Sprachentwicklungsansatz Discrete-Event Modelling with Extensibility (DMX) für die Entwicklung flexibel erweiterbarer Simulationssprachen für domänenspezifische Anwendungsfelder, der eine effiziente Entwicklung der Sprache und eine effiziente Ausführung von Modellen erlaubt. Der Fokus der Arbeit liegt auf der zeitdiskreten ereignisbasierten Simulation und einer prozessorientierten Beschreibung von Simulationsmodellen. Der Ansatz unterscheidet Basiskonzepte, die zur Basissprache gehören, und Erweiterungskonzepte, die Teil von Erweiterungsdefinitionen sind. Es wird untersucht, welche Basiskonzepte eine Simulationssprache bereitstellen muss, so dass eine laufzeiteffiziente Ausführung von prozessorientierten Modellen möglich ist. Die hohe Laufzeiteffizienz der Ausführung wird durch die Konzeption einer neuartigen Methode zur Abbildung von Prozesskontextwechseln auf ein C++-Programm gezeigt. Der Spracherweiterungsansatz ist nicht auf Simulationssprachen als Basissprachen beschränkt und wird daher allgemein beschrieben. Der Ansatz basiert auf einer Syntaxerweiterung einer Basissprache, die mit einem Metamodell und einer kontextfreien Grammatik definiert ist. Die Ausführung von Erweiterungskonzepten wird durch eine Konzeptreduktion auf Basiskonzepte erreicht. Der Ansatz stellt bestimmte Voraussetzungen an eine Basissprache und erlaubt bestimmte Arten von Erweiterungen, die in der Arbeit untersucht werden. Die Eignung des Anstatzes zur Entwicklung einer komplexen domänenspezifischen Simulationssprache wird an einer Sprache für Zustandsautomaten gezeigt. / Simulation languages are not extensible regarding the support of new domain-specific concepts with a concise representation. This includes the concepts of a language as well as the language tools. In this dissertation, the new approach Discrete-Event Modelling with Extensibility (DMX) is developed. DMX allows to create flexible domain-specific simulation languages by defining extensions to a base language. The approach allows to develop these languages efficiently and also to execute simulation models in a runtime efficient way. The focus of this dissertation is on process-oriented descriptions of discrete-event simulation models. The approach distinguishes base concepts which are part of the base language and extension concepts which are part of extension definitions. The dissertation investigates the necessary base concepts which should be included in a base simulation language in order to execute process-oriented models efficiently. The high runtime efficiency of executions is achieved by creating a new method for mapping process context switches to a program in C++. The runtime efficiency can be transferred to extension concepts as well. The extension approach is described in a general way because it is not limited to a simulation language as a base language. The approach is based on the syntax extension of a base language, which is defined by a metamodel and a context-free grammar. The execution of extension concepts is achieved by concept reduction to base concepts. The approach has a number of requirements to the base language and allows certain kinds of extensions, which are desribed in the dissertation. The possibility to define a complex domain-specific simulation language is shown by applying the approach to the development of a state machine language.

A presente pesquisa faz parte de um trabalho que visa o desenvolvimento de um método de simulação computacional que permita fazer a avaliação da qualidade da imagem radiográfica de maneira rápida e completa e que não apresente os problemas dos métodos tradicionais disponíveis e usados atualmente. Neste trabalho foi desenvolvido um método que leva em consideração e simula os parâmetros importantes dos sistemas radiológicos tais como: o tamanho e a distribuição de intensidade do ponto focal, as condições geométricas de exposição, a heterogeneidade do campo, a distribuição angular dos raios X, a grade supressora, bem como o efeito Compton. O método de simulação computacional desenvolvido realiza o controle de qualidade da imagem para um objeto colocado em qualquer posição do campo de radiação. A simulação foi feita implementando os algoritmos desenvolvidos em linguagem \"C\" e os resultados foram apresentados sob forma gráfica para facilitar a compreensão dos usuários. / This research is part of a work that aims the development of a computer simulation method which allows to evaluate the radiographic image quality in a faster and complete way, so that it doesn\'t present the problems found in the available methods used nowadays. The method developed in this work takes into consideration and simulates the important parameters of the radiologic systems such as: the focal spot size, the intensity distribution focal spot, the geometric conditions exposure, the field heterogeneity, the X-ray angular distribution, the antiscatter grid (Bucky), as well as the Compton effect. This developed computer simulation method achieves the image quality control of an object at any position of the radiation field. The simulation was done implementing the algorithms developed in C language and the results were displayed in a graphic way to facilitate the users comprehension.

[pt] Com a evolução da Internet e o crescente sucesso de ambientes Web como plataformas genéricas de aplicação, expandiram-se as necessidades de integração e coordenação de componentes de software heterogêneos e autônomos. Os requisitos específicos deste contexto impulsionaram uma nova leva de trabalhos sobre mecanismos de coordenação, dentre os quais o espaço de tuplas reativo. Neste trabalho apresentamos LuaTS, um espaço de tuplas reativo com uma dinâmica de execução orientada a eventos e com suporte apenas a chamadas assíncronas. Desenvolvido em Lua, o sistema incorpora funcionalidades diferenciadas que permitem ao programador expandir a sua semântica básica e flexibilizam o processo de busca e recuperação de tuplas. Descrevemos a implementação de LuaTS e exploramos suas particularidades através de alguns exemplos, incluindo problemas clássicos de programação concorrente e distribuída. Conforme ilustramos, os benefícios do desacoplamento proporcionado pelo modelo de espaço de tuplas, aliados à dinâmica de programação orientada a eventos, simplificam a sincronização inter-processos e geram um fluxo de execução mais claro, reduzindo em muitos casos o esforço associado ao desenvolvimento de aplicações distribuídas. / [en] The widespread use of the Internet along with the rapid growth and acceptance of the Web as a general application platform impose new requirements associated with the integration and coordination of autonomous and heterogeneous software components. The specific needs of this context led to the development of new coordination mechanisms, among which the reactive tuple space. In this work we present LuaTS, a reactive, event oriented tuple space that supports only asynchronous calls. The system, developed in Lua, provides functionalities that allow programmers to extend its basic semantics and also support a more flexible tuple search and retrieval process. We describe the implementation of LuaTS and explore its features through different examples that include classic concurrent and distributed programming problems. We show that the uncoupling provided by the tuple space model, together with an event oriented programming dynamics,simplify inter- process synchronization and yield a clear execution stream, improving, in many cases, the development process of distributed applications.

Made available in DSpace on 2016-04-27T16:57:31Z (GMT). No. of bitstreams: 1 Silvio de Brito Marcelino.pdf: 2271607 bytes, checksum: 6b6a10a1167ce96272393b8b040aaa14 (MD5) Previous issue date: 2014-05-13 / This paper describes an investigation into the use of software SuperLogo by a group of teachers of basic education in public schools of the State of São Paulo, specifically in order to understand how these teachers in activity on mathematical problems, acquire fluency in the use of interface, think math questions from the use of digital technology as well as develop / explore mathematical topics from the perspective of computational artifact. The theoretical framework of the study had by reference the Theory of Didactical Situations, the humans-with-media construct and cycle theory (use of technologies for teaching and learning mathematics). The research had qualitative approach, and analyzes were carried out from the point of view of content analysis, employing four sessions, held in a computer lab at a public school, and having by instruments for data collecting informal interviews, a questionnaire, a sequence of activities supported by non-digital technology (pencil and paper) and a didactical sequence built with problems that should be solved with the SuperLogo software. The results indicate that teachers could expand connections between mathematical knowledge available to them and the development of fluency in relation to the interface, and began to express thoughts that indicated the connection of their knowledge with the use of software, which led them to considerate the use of such resources with their student groups in the development of mathematical topics / Este trabalho descreve uma investigação sobre o uso do software SuperLogo por um grupo de professores da Educação Básica de escolas públicas do Estado de São Paulo, especificamente no sentido de compreender de que maneira os mesmos, em atividade sobre problemas matemáticos, adquirem fluência no uso da interface, pensam as questões matemáticas a partir do emprego da tecnologia digital, bem como desenvolvem/exploram temas matemáticos na perspectiva do artefato computacional. O quadro teórico do estudo teve por referência a Teoria das Situações Didáticas, o construto seres-humanos-com-mídias e a teoria do ciclo (uso de tecnologias para ensinar e aprender Matemática). A pesquisa teve caráter qualitativo, e as análises foram realizadas sob o ponto de vista da análise de conteúdo, empregando quatro sessões, realizadas em laboratório de informática de uma escola pública, e tendo por instrumentos de coleta de dados entrevistas informais, um questionário, uma sequência de atividades realizadas com suporte tecnológico não digital (lápis e papel) e uma sequência didática por meio de problemas que deveriam ser resolvidos no âmbito do SuperLogo. Os resultados indicam que os professores puderam ampliar as conexões entre o conhecimento matemático de que dispunham e o desenvolvimento de fluência em relação à interface, bem como passaram a expressar pensamentos que indicavam a conexão de seus conhecimentos com o uso do software, o que os levou a cogitar no emprego de tais recursos com seus grupos de estudantes, no desenvolvimento de temas matemáticos