This thesis is concerned with the modeling and the analysis of distributedreal-time systems. In distributed systems, components evolve partlyindependently: concurrent actions may be performed in any order, withoutinfluencing each other and the state reached after these actions does notdepends on the order of execution. The time constraints in distributed real-timesystems create complex dependencies between the components and the events thatoccur. So far, distributed real-time systems have not been deeply studied, andin particular the distributed aspect of these systems is often left aside. Thisthesis explores distributed real-time systems. Our work on distributed real-timesystems is based on two formalisms: time Petri nets and networks of timedautomata, and is divided into two parts.In the first part, we highlight the differences between centralized anddistributed timed systems. We compare the main formalisms and their extensions,with a novel approach that focuses on the preservation of concurrency. Inparticular, we show how to translate a time Petri net into a network of timedautomata with the same distributed behavior. We then study a concurrency relatedproblem: shared clocks in networks of timed automata can be problematic when oneconsiders the implementation of a model on a multi-core architecture. We showhow to avoid shared clocks while preserving the distributed behavior, when thisis possible.In the second part, we focus on formalizing the dependencies between events inpartial order representations of the executions of Petri nets and time Petrinets. Occurrence nets is one of these partial order representations, and theirstructure directly provides the causality, conflict and concurrency relationsbetween events. However, we show that, even in the untimed case, some logicaldependencies between event occurrences are not directly described by thesestructural relations. After having formalized these logical dependencies, wesolve the following synthesis problem: from a formula that describes a set ofruns, we build an associated occurrence net. Then we study the logicalrelations in a simplified timed setting and show that time creates complexdependencies between event occurrences. These dependencies can be used to definea canonical unfolding, for this particular timed setting.

Le raisonnement epistémique joue un rôle en théorie de la concurrence de plusieurs manières distinctes mais complémentaires; cette thèse en décrit trois. La première, et presque certainement la moins explorée jusqu'à présent, est l'idée d'utiliser les modalités épistémiques comme éléments d'un langage de programmation. La programmation logique émergea sous le slogan <> et dans le paradigme de la programmation concurrente par contraintes, le lien est manifeste de manière très claire. Dans la première partie de cette thèse, nous explorons le rôle des modalités épistémiques, ainsi que celui des modalités spatiales qui leur sont étroitement liées, en tant que partie intégrante du langage de programmation et non simplement en tant que partie du meta-langage du raisonnement à propos des protocoles. La partie suivante explore une variante de la logique épistémique dynamique adaptée aux systèmes de transitions étiquetés. Contrairement à la partie précédente, on serait tenté de croire que tout ce qu'on pouvait dire à ce sujet a déjà été dit. Cependant, le nouvel ingrédient que nous proposons est un lien étroit entre la logique épistémique et la logique de Hennessy-Milner, cette dernière étant \emph{la} logique des systèmes de transitions étiquetés. Plus précisement, nous proposons une axiomatisation et une preuve d'un théorème de complétude faible, ce qui est conforme au principe général qu'on utilise pour des logiques telles que la logique dynamique mais nécessite des adaptations non triviales. La dernière partie de la thèse se concentre sur l'étude d'agents en interaction dans les processus concurents. Nous présentons une sémantique des jeux pour l'interaction d'agents qui rend manifeste le rôle de la connaissance et du flux d'information dans les interactions entre agents, et qui permet de contrôler l'information disponible aux agents en interaction. Nous utilisons les processus comme support de jeu et définissons des stratégies pour les agents de telle sorte que deux agents qui interagissent conformément à leurs stratégies respectives déterminent l'exécution du processus, rempla{\c}cant ainsi l'ordonnanceur traditionnel. Nous démontrons que des restrictions différentes sur les stratégies réprésentent des quantités d'information différentes disponibles à l'ordonnanceur. Ces restrictions sur les stratégies ont un aspect épistémique explicite, et nous présentons une logique modale pour les stratégies et une caractérisation logique de plusieurs restrictions possibles sur les stratégies. Ces trois approches d'analyse et de représentation de l'information épistémique en théorie de la concurrence apportent une nouvelle manière de comprendre la connaissance des agents dans des processus conncurrents, ce qui est vital dans le monde d'aujourd'hui, dans lequel les systèmes distribués composés de multiples agents sont omniprésents.

Un système GALS (Globalement Asynchrone, Localement Synchrone) est un ensemble de composants synchrones qui évoluent en même temps, chacun à propre rythme, et qui communiquent de manière asynchrone. Cette thèse propose un environnement formel de modélisation et de vérification dédié aux systèmes GALS, en se focalisant sur le comportement asynchrone.Notre environnement s’appuie sur un langage formel que nous avons conçu nommé GRL (GALS Représentation Language). GRL permet la spécification comportementale des composants synchrones, de la communication asynchrone, et des contraintes sur les rythmes des composants ainsi que sur les valeurs que prennent les entrées des composants. Pour analyser les spécifications GRL, nous utilisons CADP, une boîte à outils logicielle permettant la vérification de processus concurrents asynchrones par des techniques d'exploration d’espaces d’états. Dans ce but, nous avons défini une traduction de GRL vers LNT, un langage de spécification supporté par CADP. La traduction est implémentée dans un outil appelé GRL2LNT, permettant ainsi la génération automatique d’espaces d'états à partir de spécifications GRL.Pour permettre la vérification formelle des spécifications GRL, nous avons conçu un langage de propriétés nommé muGRL, qui est interprété sur les espaces d’états de GRL. Le langage muGRL est basé sur un ensemble de patrons qui capturent les propriétés des systèmes concurrents et des systèmes GALS, réduisant ainsi la complexité d'utiliser les logiques temporelles classiques. La sémantique de muGRL est définie par traduction vers MCL, le langage de logique temporelle fourni par CADP. Enfin, nous illustrons l’usage de GRL, muGRL et CADP pour la modélisation et la vérification d’applications GALS concrètes, comprenant des études de cas industrielles. / A GALS (Globally Asynchronous, Locally Synchronous) system consists of several synchronouscomponents that evolve concurrently, each with its own pace, and communicatealtogether asynchronously. This thesis proposes a formal modelling and verificationframework dedicated to GALS systems, with a focus on the asynchronous behaviour.As a cornerstone of our framework, we have designed a formal language, named GRL(GALS Representation Language). GRL enables the behavioural specification of synchronouscomponents, asynchronous communication, and constraints involving bothcomponent paces and the data carried by component inputs. To analyse GRL specifications,we took advantage of the CADP software toolbox for the verification of asynchronousconcurrent processes, using state space exploration techniques. For this purpose,we defined a translation from GRL to the LNT specification language supportedby CADP. The translation was implemented by a tool named GRL2LNT, thus enablingstate spaces to be automatically derived from GRL specifications.To enable the formal verification of GRL specifications, we designed a property specificationlanguage, named muGRL, which is interpreted on GRL state spaces. The muGRLlanguage is based on a set of patterns capturing properties of concurrent and GALSsystems, which reduces the complexity of using full-fledged temporal logics. The semanticsof muGRL are defined by a translation into the MCL temporal logic supported byCADP. Finally, we illustrated how GRL, muGRL, and CADP can be applied to modeland verify concrete GALS applications, including industrial case-studies.

Multidatabases are being actively researched as a relatively new area in which many aspects are not yet fully understood. This area of transaction management in multidatabase systems still has many unresolved problems. The problem areas which this dissertation addresses are classification of multidatabase systems, global concurrency control, correctness criterion in a multidatabase environment, global deadlock detection, atomic commitment and crash recovery. A core group of research addressing these problems was identified and studied. The dissertation contributes to the multidatabase transaction management topic by introducing an alternative classification method for such multiple database systems; assessing existing research into transaction management schemes and based on this assessment, proposes a transaction processing model founded on the optimal properties of transaction management identified during the course of this research. / Computing / M. Sc. (Computer Science)

Orientador: Maria Beatriz Felgar de Toledo / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Computação / Made available in DSpace on 2018-08-16T08:41:15Z (GMT). No. of bitstreams: 1 Pierre_AllynGreydeAlmeidaLima_M.pdf: 1760009 bytes, checksum: 4af51767131cfa3c30ee8f7ea8830949 (MD5) Previous issue date: 2009 / Resumo: Dentre as tecnologias emergentes, a computação móvel tem a sua posição de destaque. Os dispositivos móveis estão mais presentes na vida das pessoas e contendo aplicações mais sofisticadas e semelhantes às executadas em computadores pessoais. Num mundo globalizado, onde o tempo é escasso e valioso, os dispositivos móveis mantêm as pessoas em contato com informações e atividades que elas desejam enquanto elas estão em movimento. Um exemplo recente é aumento do uso da internet em celulares, permitindo que os usuários acessem diversos tipos de aplicações, tendo grande parte delas interação com bancos de dados. Apesar de atrativa, a computação móvel traz desafios ao desenvolvedor, pois ele deve considerar os recursos limitados tais como largura de banda, conectividade e o alto custo da obtenção de dados. Nesse contexto, as transações representam um importante papel de garantir que o dinamismo do ambiente da computação móvel não comprometa a confiabilidade das aplicações. Porém, algumas aplicações não podem ser implementadas considerando o modelo de transações tradicional, pois elas têm um tempo mais longo de duração do que aquelas convencionalmente modeladas. Sendo assim, as configurações de uma transação realizadas no início de sua execução podem deixar de ser adequadas no decorrer da sua execução, devido às mudanças no ambiente. Diversos modelos de transações têm sido apresentados na literatura para atender a esse ambiente. Apesar de muitas idéias interessantes e relevantes, alguns modelos não permitem que a adaptação diante da variação dos recursos seja realizada durante a execução de uma transação e quando permitem, eles realizam grandes reconfigurações arquiteturais. Motivada por essas questões, essa dissertação propõe transações reconfiguráveis, isto é, a configuração dinâmica de mecanismos transacionais antes do início da transação e a reconfiguração de propriedades transacionais durante sua execução. Para que a reconfiguração dinâmica fosse realizada, um modelo de componentes chamado OpenCOM foi utilizado na arquitetura proposta, por este ser reflexivo, leve e independente de plataforma. O nível de isolamento é a propriedade transacional que poderá ser reconfigurada durante a transação e o controle de concorrência é o mecanismo que garantirá o isolamento entre as transações e poderá ser configurado antes do início da transação. A configuração do controle de concorrência é uma contribuição inovadora dessa dissertação, pois em muitos trabalhos existentes não é possível a configuração desse mecanismo transacional. A fim de validar a arquitetura proposta, um protótipo de um sistema de vendas foi desenvolvido. Através dessa implementação foi possível analisar os impactos da reconfiguração durante uma transação / Abstract: Among the emerging technologies, mobile computing has its position of prominence. Mobile devices are more present in people's lives and with more sophisticated applications similar to those implemented in personal computers. In a globalized world where time is scarce and of great importance, mobile devices keep people in touch with information and activities they want while they are moving. A recent example is the increasing use of the Internet on mobile phones allowing users to access various types of applications and much of them interacting with databases. Although attractive, the mobile computing brings challenges to the developer because he must consider the limited resources such as bandwidth, connectivity and the high cost of obtaining data. In this context, the transactions represent an important role to ensure that the dynamic environment of mobile computing does not compromise the reliability of applications. However some applications cannot be implemented given the traditional transactions models because they have a longer duration than those conventionally shaped. Therefore the settings of a transaction carried out before its execution may not be appropriate during the execution due to changes in the environment. Various transactions models have been reported in the literature to serve this environment. Although having many interesting and relevant ideas, some models do not allow the adaptation in the face of change of resources during the execution of a transaction and when this is allowed, they require many transactional reconfigurations. Motivated by these issues, this dissertation proposes reconfigurable transactions that are the dynamic configuration of transactional mechanisms before the beginning of the transaction and the reconfiguration of transactional properties during its execution. For dynamic reconfiguration, a component model called OpenCOM has been used in the proposed architecture because it is reflective, lightweight and platform-independent. The isolation level is the property that may be reconfigured during the transaction and the concurrency control is the mechanism that ensures the isolation between the transactions and it can be configured before the beginning of transaction. The configuration of concurrency control is an original contribution of this dissertation because many works do not allow the configuration of this transactional mechanism. In order to validate the proposed architecture, a prototype of a sales system has been developed. Through this implementation it was possible to analyze the impacts of the reconfiguration during a transaction / Mestrado / Sistemas Distribuidos / Mestre em Ciência da Computação

Eine der stärksten Erweiterungen der klassischen Theorie formaler Sprachen und Automaten ist die Einbeziehung von Gewichten oder Vielfachheiten aus einem Halbring. Diese Dissertation untersucht gewichtete Automaten über Strukturen mit Nebenläufigkeit. Wir erweitern die Arbeit von Lodaya und Weil und erhalten so ein Modell gewichteter verzweigender Automaten, in dem die Berechnung des Gewichts einer parallelen Komposition anders als die einer sequentiellen Komposition gehandhabt wird. Die von Lodaya und Weil eingeführten Automaten modellieren Nebenläufigkeit durch Verzweigen. Ein verzweigender Automat ist ein endlicher Automat mit drei verschiedenen Typen von Transitionen. Sequentielle Transitionen überführen durch Ausführen eines Ereignisses einen Zustand in einen anderen. Dagegen sind Gabel- und Binde-Transitionen für das Verzweigen verantwortlich. Läufe dieser Automaten werden beschrieben durch sequentiell-parallele posets, kurz sp-posets. Alle Transitionen des Automaten werden in unserem Modell mit Gewichten versehen. Neben dem Nichtdeterminismus und der sequentiellen Komposition wollen wir nun auch die parallele Komposition quantitativ behandeln. Dafür benötigen wir eine Gewichtsstruktur mit einer Addition, einer sequentiellen und einer parallelen Multiplikation. Solch eine Struktur, genannt Bihalbring, besteht damit de facto aus zwei Halbringen mit derselben additiven Struktur. Weiterhin muss die parallele Multiplikation kommutativ sein. Das Verhalten eines gewichteten verzweigenden Automaten ist dann eine Funktion, die jeder sp-poset ein Element eines Bihalbrings zuordnet. Das Hauptresultat charakterisiert das Verhalten dieser Automaten im Sinne von Kleenes und Schützenbergers Sätzen über das Zusammenfallen der Klassen der erkennbaren und der rationalen Sprachen bzw. formalen Potenzreihen. Darüber hinaus untersuchen wir den Abschluss dieser Verhalten unter allen rationalen Operationen und unter dem Hadamard-Produkt. Letztlich diskutieren wir Zusammenhänge zwischen Reihen und Sprachen im Rahmen verzweigender Automaten. / One of the most powerful extensions of classical formal language and automata theory is the consideration of weights or multiplicities from a semiring. This thesis investigates weighted automata over structures incorporating concurrency. Extending work by Lodaya and Weil, we propose a model of weighted branching automata in which the calculation of the weight of a parallel composition is handled differently from the calculation of the weight of a sequential composition. The automata as proposed by Lodaya and Weil model concurrency by branching. A branching automaton is a finite-state device with three different types of transitions. Sequential transitions transform a state into another one by executing an action. In contrast, fork and join transitions are responsible for branching. Executions of such systems can be described by sequential-parallel posets, or sp-posets for short. In the model considered here all kinds of transitions are equipped with weights. Beside non-determinism and sequential composition we would like to deal with the parallel composition in a quantitative way. Therefore, we are in need of a weight structure equipped with addition, a sequential, and, moreover, a parallel multiplication. Such a structure, called a bisemiring, is actually composed of two semirings with the same additive structure. Moreover, the parallel multiplication has to be commutative. Now, the behavior of a weighted branching automaton is a function that associates with every sp-poset an element from the bisemiring. The main result characterizes the behavior of these automata in the spirit of Kleene's and Schützenberger's theorems about the coincidence of recognizable and rational languages, and formal power series, respectively. Moreover, we investigate the closure of behaviors under all rational operations and under Hadamard-product. Finally, we discuss connections between series and languages within our setting.

La sémantique des jeux est une sémantique dénotationnelle centrée sur l’interaction : preuves et programmes y sont représentés par des stratégies modélisant, par le flot d’exécution, leur manière de réagir à leur environnement. Malgré cette présentation intensionnelle, les sémantiques de jeux ne suffisent pas à capturer certaines informations calculatoires annexes au flot d’exécution telles que, par exemple, la production de témoins en logique du premier ordre ou la consommation de ressources dans les langages de programmation. Dans cette thèse nous proposons un enrichissement du modèle des jeux concurrent à base de structures d’événements permettant de garder trace de ces informations.Nous construisons d’abord un modèle de jeux concurrent dans lequel les coups joueurs d’une stratégie sont annotés par les termes d’une théorie (in)équationnelle. Cette théorie est un paramètre de notre modèle et les annotations permettent de refléter de manière compacte des informations d’exécution n’ayant pas d’influence sur le flot d’exécution. Nous montrons que le modèle ainsi construit préserve la structure catégorique compacte fermée du modèle sans annotation.Nous explorons ensuite l’expressivité de notre modèle et présentons deux interprétations nouvelles en sémantique des preuves et des programmes : l’une interprétant les preuves de la logique classique du premier ordre par des stratégies concurrentes avec échange de témoins, donnant une version compositionnelle au théorème de Herbrand ; l’autre permettant de refléter les aspects quantitatifs liés à la consommation de ressources telles que le temps, dans l’exécution de programmes concurrents d’ordre supérieur avec mémoire partagée. / This thesis presents a general framework for enriching causal concurrent games model with annotations. These annotations can be viewed as meta-data on strategies: they are modified throughout interactions but do not affect their general flow of control. These data can be of various nature, in particular our enrichment is parametrised over any multi-sorted equational theory and can also reflect structure upon these data such as a partial order. From a semantics point of view, this construction is motivated by problems from both logic and programming languages: On the logic side, the annotated games model specialised to first-order terms enables us to give a novel interpretation of first-order classical proofs as concurrent strategies carrying first-order witnesses. In particular this answer the question of giving a compositional version to Herbrand’s theorem while avoiding the usual proof sequentialization of other denotational approaches. On the programming language side, annotations on games offer intrinsic quantitative models. We show that those can be used to provide denotational semantics for resource consumption analysis of concurrent higher order programming language with shared memory.These enrichments, strongly connected to the causal structure of concurrent games, give an argument in favor of a causal meaning of computations.

[pt] Redis é um banco de dados chave-valor de código livre que dá suporte à avaliação de scripts Lua, mas sua implementação utiliza apenas uma tarefa de sistema operacional. Scripts longos são desencorajados porque a avaliação do código é bloqueante, o que pode causar degradação de desempenho para os demais usuários. Através da aplicação do modelo de concorrência M:N, que combina tarefas de nível de sistema operacional com tarefas do nível de usuário, adicionamos no Redis a capacidade de execução de scripts em paralelo, permitindo que todos os núcleos do servidor sejam explorados. Com a utilização de corotinas Lua, implementamos um escalonador capaz de alocar e suspender a execução de tarefas de nível de usuário nos núcleos disponíveis sem necessidade de alteração do código dos scripts. Este modelo permitiu proteger o programador das complexidades naturais do paralelismo como sincronização no acesso a recursos compartilhados e escalonamento das tarefas. / [en] Redis is an open source key-value database that supports Lua programming language scripts, but it s implementation is single threaded. Long running scripts are discouraged because script evaluation is blocking, which may cause service levels deterioration. Applying the M:N threading model, which combines user and operating system threads, we added to Redis the ability of running scripts in parallel, leveraging all server cores.With the use of Lua coroutines, we implemented a scheduler able to allocate and suspend user-level tasks in the available cores without the need of changing scripts source code. The M:N model allowed us to protect the programmer from the natural complexities that arise from parallel programming, such as access to shared resources synchronization and scheduling of tasks into different operational system threads.

V disertační práci je nejprve uvedena taxonomie chyb v souběžném zpracování dat a přehled technik pro jejich dynamickou detekci. Následně jsou navrženy nové metriky pro měření synchronizace a souběžného chování programů společně s metodologií jejich odvozování. Tyto techniky se zejména uplatní v testování využívajícím techniky prohledávání prostoru a v saturačním testování. Práce dále představuje novou heuristiku vkládání šumu, jejímž cílem je maximalizace proložení instrukcí pozorovaných během testování. Tato heuristika je porovnána s již existujícími heuristikami na několika testech. Výsledky ukazují, že nová heuristika překonává ty existující v určitých případech. Nakonec práce představuje inovativní aplikaci stochastických optimalizačních algoritmů v procesu testování vícevláknových aplikací. Principem metody je hledání vhodných kombinací parametrů testů a metod vkládání šumu. Tato metoda byla prototypově implementována a otestována na množině testovacích příkladů. Výsledky ukazují, že metoda má potenciál vyznamně vylepšit testování vícevláknových programů.

The research area this report relates to is real-time automatic transcription and translation. The purpose of the work done for the report is to reduce the perceived language barriers online and to make a user-friendly application to make use of the latest deep learning technology to transcribe and translate in real-time. This application could be used in a work environment (especially when working from home) and for leisure activities such as watching videos. There is currently most likely no application that uses automatic speech recognition in this way. The most similar applications that were found were mainly similar to Google Translate which are not meant for real-time usage on a computer but rather to wait for an input and then write it out when it is completely done. The application created for this purpose was a desktop application that combines Open-AI's Whisper model for transcription and Argos Translate for translation into one application with a user-friendly GUI created with Java Swing. For creating the application, an iterative and incremental methodology was used both for the GUI design and the software development. In the end, the development was successful resulting in a working desktop application accomplishing the goals of transcribing and translating in real-time with the user of a user-friendly application, which could for example easily be used for digital meetings or videos online. / Det område som denna rapport handlar om är automatisk transkription och översättning i realtid. Syftet med arbetet som gjorts för rapporten är att minska de upplevda digitala språkbarriärerna och att göra en användarvänlig applikation för att använda den senaste djup maskininlärnings teknologin för att transkribera och översätta i realtid. Just nu finns det med största sannolikhet inget program som använder automatisk röstigenkänning på detta sätt. De mest liknande applikationerna som var funna är sådanna som liknar Google Translate, men dessa är inte skapade för anvädning i realtid utan istället för att höra hela indatan och sedan skriva ut hela resultatet. Applikationen som skapades med detta syfte var en datorapplikation som kombinerar Open-AIs Whisper-modell för transkription och Argos Translate för översättning till en applikation med ett användarvänligt grafiskt användargränssnitt skapat med Java Swing. För att skapa applikationen användes en iterativ och inkrementell metodik både för den grafiska användargränssnittsdesignen och mjukvaruutvecklingen. Resultatet var lyckat vilket ledde till en fungerande dator applikation som uppnådde målen att transkribera och översätta i realtid med en användarvänlig applikation.