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Contributions à la synthèse de commande des systèmes à évènements discrets : nouvelle modélisation des états interdits et application à un atelier flexible / A contribution to control synthesis of Discrete Event systems : New model of forbidden states (applied on a flexible workshop)Atli, Maen 27 September 2012 (has links)
Un Système de production peut être représenté par les systèmes à événements discrets. En dehors de la planification (où les gens travaillent avec des ratios de produits fabriqués par semaine ou par jour), la modélisation pourrait être basée sur les concepts d'événement et d'activités. Un événement correspond à un changement d'état. Une activité est une boîte noire d'encapsulation de ce qui se passe entre deux événements. En utilisant les réseaux de Petri (RdP), les événements sont représentés par les transitions, et les activités par les lieux. Notre travail propose une synthèse de commande par supervision pour les systèmes d'événements discrets modélisés par une classe de réseaux de Petri appelé graphe d'événements. L'objective de cette thèse est de concevoir un superviseur capable d'aider à améliorer la performance de système et de protéger le système en respectant des spécifications données par le fabricant ou le client selon les besoins et les conditions de travail. Pour modéliser ces spécifications, nous avons proposé un nouveau modèle mathématique de contrainte, appelé Contrainte d'Exclusion de Marquage (CEM). La deuxième contribution principale de ma thèse est de synthétiser une technique efficace et simple pour construire un superviseur qui impose le système de respecter des contraintes en évitant l'ensemble des états interdits modélisé par CEM. Nous avons également développé cette synthèse pour résoudre le problème d'existence des événements incontrôlables et des événements inobservables. Parfois, afin d'étudier les aspects liés à la performance, nous devons prendre le temps en considération. Donc, nous avons résolu aussi le problème des événements temporisé en utilisant RdP temporisés soumis à CEM / A manufacturing system may be represented by Discrete Event System (DES). Apart from planning (where people work with ratios of products fabricated per week or per day), any modelling could be based on the concepts of event and activities. An event corresponds to a state change. An activity is a black-box summarizing what is occurring between two events. When using Petri Nets, events are associated with transitions, and activities with places. Our work proposes a supervisory synthesis for Discrete Event System modelled by a class of Petri Net called Marked Graph. The objective of this synthesis is to build a control law that enforces the system to respect a set of given specifications. To model these specifications, we propose new mathematical formulas called Marking Exclusion Constraint (MEC). This model is our first contribution. The Second main contribution of my thesis is to synthesize a computationally efficient technique to build a supervisor that enforces the system to respect the constraints by avoiding a set of forbidden states modelled by MEC specifications. We extend this synthesis technique to solve the problem in the presence of uncontrollable events and unobservable events. Sometimes in order to study the performance aspects, we must take in consideration the time data. Thus we address control synthesis for Timed Discrete Event Systems under MEC specifications by using Timed Petri Nets
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Évaluation de performance d’architecture de contrôle-commande en réseau dans un contexte incertain d’avant-vente / Performance assessment of Networked Control System (NCS) during uncertain pre-sales contextNdiaye, Moulaye A.A. 16 March 2017 (has links)
Ce mémoire, réalisé dans le cadre d’une thèse sous convention CIFRE avec la société Schneider-Electric et l’Université de Lorraine à travers le laboratoire du CRAN, porte sur l’évaluation des performances temporelles des architectures de contrôle-commande distribuées sur un réseau de communication. Le besoin industriel s’exprime sous la forme d’un outil d’aide au dimensionnement des architectures en phase d’avant-vente caractérisée par une connaissance partielle de ces dernières. Le problème scientifique sous-jacent est relatif à la génération automatique des modèles servant de support à l’évaluation. En effet, l’évaluation des performances doit être réalisée pour un ensemble important d’architectures, dans un temps court, difficilement compatible avec une construction manuelle des modèles. Notre contribution porte sur la définition formelle, à l’aide de réseaux de Petri colorés et temporisés, d’un modèle « constructeur » d’architectures embarquant des mécanismes de configuration, d’instanciation et de paramétrage. Plusieurs algorithmes sont proposés pour, d’une part, construire automatiquement le modèle d’une architecture donnée, à partir d’une description formelle de sa topologie et d’une librairie de modèles d’équipements de contrôle-commande, et, d’autre part, pour générer les observateurs requis à partir d’une description formelle des performances à évaluer. Ces différents algorithmes ont été implantés dans un outil interfacé, d’une part avec l’outil Schneider de description des architectures, et, d’autre part avec le simulateur de l’outil CPN Tools qui fournit une estimation des performances via des simulations de Monte-Carlo. L’intérêt de cette approche a été illustrée sur la base de quelques architectures types fournies par la société Schneider-Electric / This PhD dissertation, supported by CIFRE convention between the company Schneider-Electric and the University of Lorraine through the CRAN laboratory, deals with the assessment of temporal performances for a networked distributed control system. The industrial need was the development of a quotation and sizing tool of industrial control architecture during pre-sales stage. This stage is characterized by limited information about the process and the customers’ needs. The underlying scientific problematic was the ability to generate automatically models serving as support for the evaluation. In fact, performance assessment is realized for a wide range of architecture during a small amount of time, which is not compliant with a manual definition of the models. Our contribution is mainly based on a formal definition of a “builder” model with Colored and Timed Petri Nets which embeds mechanisms for configuration, instantiation and parameters setting of the architecture models. Several algorithms have been proposed for firstly build automatically the architecture Petri Nets model from a formal description of the topology and from a component model library and, secondly, for generating performance observers. Theses algorithms have been implemented on a tool gathering a user interface developed by Schneider –Electric and the Petri Nets simulator called CPN Tools which provides the performance assessment through Monte-Carlo simulation. The added value of this approach has been illustrated through case studies provided by Schneider-Electric
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Validation formelle des systèmes numériques critiques : génération de l'espace d'états de réseaux de Petri exécutés en synchrone / Formal validation of critical digital systems : generation of state space of Petri nets executed in synchronousMerzoug, Ibrahim 15 January 2018 (has links)
La méthodologie HILECOP a été élaborée pour la conception formelle de systèmes numériques complexes critiques ; elle couvre donc l'intégralité du processus, allant de la modélisation à la génération de code pour l’implantation sur la cible matérielle (composant électronique de type FPGA), en passant par la validation formelle. Or, si le modèle formel, les réseaux de Petri en l'occurrence, est par essence asynchrone, il est néanmoins exécuté de manière synchrone sur la cible. De fait, les approches d'analyse usuelles ne sont pas adaptées au sens où elles construisent des graphes d'états non conformes à l'évolution d'états réelle au sein de la cible. Dans l'objectif de gagner en confiance quant à la validité des résultats de l’analyse formelle, ces travaux visent à capturer les caractéristiques dites non-fonctionnelles, à les réifier sur le modèle et enfin à considérer leur impact à travers l’analyse. En d’autres termes, l’objectif est d’améliorer l’expressivité du modèle et la pertinence de l'analyse, en considérant des aspects comme la synchronisation d'horloge, le parallélisme effectif, le risque de blocage induit par l'expression conjointe d'un événement (condition) et d'une fenêtre temporelle d'occurrence, sans omettre la gestion des exceptions. Pour traiter tous ces aspects, nous avons proposé une nouvelle méthode d'analyse pour les réseaux de Petri temporels généralisés étendus interprétés exécutés en synchrone, en les transformant vers un formalisme équivalent analysable. Ce formalisme est associé avec une sémantique formelle intégrant toutes les aspects particuliers de l'exécution et un algorithme de construction d'un graphe d'états spécifique : le Graphe de Comportement Synchrone. Nos travaux ont été appliqués à un cas industriel, plus précisément à la validation du comportement de la partie numérique d'un neuro-stimulateur. / The HILECOP methodology has been developed for the formal design of critical complex digital systems; it therefore covers the entire design process, ranging from modeling to code generation for implementation on the hardware target (FPGA type electronic component), via formal validation. However, if the formal model, the Petri nets in this case, is inherently asynchronous, it is nevertheless executed synchronously on the target. In fact, the usual analysis approaches are not adapted in the sense that they construct state graphs that do not conform to the real state evolution within the target. In order to gain confidence in the validity of the results of the formal analysis, this work aims to capture the so-called non-functional characteristics, to reify them on the model and finally to consider their impact through the analysis.In other words, the aim is to improve the expressiveness of the model and the relevance of the analysis, considering aspects such as clock synchronization, effective parallelism, the risk of blocking induced by the expression of an event (condition) and a time window of occurrence, without omitting the management of exceptions.To deal with all these aspects, we have proposed a new method of analysis for extended generalized synchronous executed time Petri nets, transforming them into an analysable equivalent formalism. This formalism is associated with a formal semantics integrating all the particular aspects of the execution and dédicated state space construction algorithm: the Synchronous Behavior Graph.Our work has been applied to an industrial case, more precisely to the validation of the behavior of the digital part of a neuro-stimulator.
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Proposta de um procedimento para a modelagem de sistemas de controle de edifícios inteligentes utilizando a rede de Petri colorida. / A procedure for modelling the control system in intelligent buildings based on colored Petri nets.Igei Kaneshiro, Percy Javier 22 August 2011 (has links)
Os avanços tecnológicos das últimas décadas têm motivado o desenvolvimento dos edifícios inteligentes, visando à criação de ambientes mais confortáveis e seguros para os ocupantes, economicamente vantajosos para os proprietários e ambientalmente corretos. Considerando-se que nestes ambientes emergem novas formas de interação entre os usuários e os sistemas prediais, as quais não são adequadamente tratadas por técnicas convencionais de modelagem, torna-se necessário o estudo de novas soluções que abordem essas interações. Assim, este trabalho apresenta a proposta de uma abordagem sistemática para modelar e simular os sistemas de controle de edifícios inteligentes. Considera-se o sistema de controle como um sistema orientado por eventos discretos, no qual a comunicação entre os dispositivos que o constituem é realizada por meio da troca assíncrona de mensagens. Nesta abordagem, é utilizada a rede de Petri colorida para especificar as funcionalidades do edifício inteligente e a interação entre os dispositivos que constituem o seu sistema de controle. Assim, fornece-se um procedimento estruturado para desenvolver modelos que facilita a especificação do algoritmo de controle dos subsistemas do edifício inteligente. Para avaliar as principais características do procedimento proposto, foi apresentado um exemplo de aplicação que aborda a integração das funcionalidades de um sistema de telefonia distribuído e um sistema de vigilância predial. A abordagem de modelagem possibilitou a identificação das funcionalidades dos dispositivos inteligentes que integram o sistema de controle em diferentes níveis de abstração e as interações que ocorrem durante o seu funcionamento. A realização deste trabalho contribui para o aprimoramento de novas abordagens para o desenvolvimento de sistemas de controle com arquiteturas heterárquicas. Estes sistemas são constituídos por dispositivos inteligentes colaborativos, que possuem um elevado grau de autonomia. / Technological advances in recent decades have motivated the development of intelligent buildings, aimed at creating environments more productive for the occupants, economically advantageous for the owners and environmentally correct. New ways of interaction between users and the buildings systems are emerging from these kinds of systems, which are not adequately treated by conventional modeling techniques. In this sense, it is necessary the study of new approaches which address these new functionalities. Thus, this work presents a proposal for a systematic approach to model and simulate the control system of the intelligent buildings. The control system is considered to be a discrete event system, where the communication between the devices that integrate it is oriented by means of asynchronous messages exchange. This approach uses the colored Petri nets in order to specify the functionalities of the building system and their devices interactions. The approach provides a structured procedure to develop models that facilitate the algorithm specification of the control system. In order to verify the main characteristics of the proposed procedure, it is presented an example that is a control system that integrates a distributed telephony system and a surveillance building system. The approach proposed enabled the identification of the main functionalities and interactions of the intelligent devices constituting the control system. The achievement of this thesis contributes to the development of new approaches to develop heterarchical control system architectures. This kind of system architectures is constituted by collaborative intelligent devices that have a high degree of autonomy.
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Análise de políticas de controle de acesso baseado em papéis com rede de Petri colorida. / Policies analysis of role based access control with colored Petri net.Ueda, Eduardo Takeo 24 May 2012 (has links)
Controle de acesso é um tópico de pesquisa importante tanto para a academia quanto para a indústria. Controle de Acesso Baseado em Papéis (CABP) foi desenvolvido no início dos anos 1990, tornando-se um padrão generalizado para controle de acesso em vários produtos e soluções computacionais. Embora modelos CABP sejam largamente aceitos e adotados, ainda existem questões para responder. Um dos principais desafios de pesquisa em segurança baseada em papéis é determinar se uma política de controle de acesso é consistente em um ambiente altamente dinâmico. Nossa pesquisa visa preencher essa lacuna fornecendo um método para analisar políticas CABP com respeito a dois aspectos significativos: segurança e dinamismo envolvendo papéis e objetos. Para este propósito, desenvolvemos um modelo de descrição e simulação de política usando rede de Petri colorida e CPN Tools. O modelo descreve e é capaz de simular vários estados CABP em um contexto de educação a distância típico. Usando este modelo, foi possível analisar o espaço de estados produzido pela rede de Petri colorida em um cenário dinâmico envolvendo a criação de novos papéis e objetos. O resultado da análise de alcançabilidade da rede de Petri da política demonstrou que é possível verificar a consistência de políticas de controle de acesso considerando a dinamicidade de papéis e objetos, e apontou vantagens de aplicabilidade da modelagem de políticas de segurança em ambientes distribuídos utilizando rede de Petri colorida. / Access control is an important research topic both for academia and industry. Role Based Access Control (RBAC) was developed in the early 1990s, becoming a generalized standard of access control for many products and computing solutions. Although RBAC models have been widely accepted and adopted, there are issues to answer. One of the key challenges for role-based security research is to characterize whether an access control policy is consistent in a highly dynamic environment. Our research aims filling this gap providing a method to analyze RBAC policies with respect to two significant aspects: security and dynamics involving roles and objects. For this purpose, we developed a policy description and simulation model using colored Petri net and the CPN Tools. The model describes and is capable to simulate many RBAC states in a typical distance education context. Using this model it was possible to analyze the state space provided by colored Petri net that simulates a dynamic environment and the creation of new roles and objects. The result of the reachability analysis of Petri net policy showed that it is possible to check the consistency of access control policies considering dynamic of roles and objects, and point out the advantages and applicability of modeling security policies in distributed environments using colored Petri net.
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Modelagem de sistemas de controle de edifícios inteligentes considerando a ocorrência de falhas. / Control systems modeling of intelligent buildings considering the faults occurrence.Silva, Robson Marinho da 19 November 2008 (has links)
Sistemas de controle de edifícios inteligentes têm evoluído consideravelmente e a sua confiabilidade também tem melhorado. Mesmo assim, falhas são inevitáveis em sistemas concebidos, construídos e operados pelo homem e uma abordagem alternativa envolve a minimização das conseqüências das falhas. Isto é possível através da reconfiguração do sistema que se faz realocando funções de controle e escolhendo outras formas de interação entre os processos. Apesar disso, na literatura ainda não existe muito material que trate da modelagem de processos em que desde a sua concepção as falhas são consideradas. Assim, propõe-se neste trabalho o desenvolvimento de um procedimento para a modelagem de sistemas de controle considerando além das especificações funcionais, em situação normal, a ocorrência de falhas. Em função da base teórica existente e ferramentas disponíveis a abordagem proposta adota o conceito de sistemas a eventos discretos, holon e a técnica de rede de Petri e suas extensões para descrever a estrutura e o funcionamento deste sistema de controle. Um exemplo de aplicação é aqui apresentado para ilustrar as principais características deste procedimento. / Control systems of intelligent buildings have evolved and its reliability has evidently improved. However, faults are inevitable in systems conceived, constructed and operated by humans and an alternative approach is the minimization of the faults consequences. This is possible through the reconfiguration of the system, i.e., re-allocating control functions and choosing other forms of interaction between the processes. Despite this, there are few publications that deal with the modeling of processes where since its conception the faults are considered. Thus, this work proposes the development of a procedure for the modeling of control systems considering beyond the functional specifications in normal situation, the occurrence of faults. Based on the existing theoretical base and available tools the proposal adopts the concept of discrete event system, holon and Petri net technique with its extensions to describe the structure and the operation of these control systems. An application example is here presented to illustrate the principal characteristics of this proceeding.
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Sémantique formelle et vérification automatique de scénarios hiérarchiques multimédia avec des choix interactifs / Formal semantics and automatic verification of hierarchical multimedia scenarios with interactive choicesArias Almeida, Jaime E. 27 November 2015 (has links)
Notre propos est la conception assistée par ordinateur des scénarios comprenant des contenus multimédia qui interagissent avec les actions extérieures, notamment celles de l’interprète (e.g., spectacles vivants, installations muséales interactives et jeux vidéo). Le contenu multimédia est structuré dans un ordre spatial et temporel selon les exigences de l’auteur. Par conséquent, la complexité potentiellement élevée de ces scénarios nécessite des langages de spécification adéquats pour leur complète description et vérification.Partitions Interactives est un formalisme qui a été proposé comme un modèle pour la composition et l’exécution des scénarios multimédias interactifs. En outre, un séquenceur inter-médias, appelé ISCORE,a été élaboré à partir de la sémantique Petri net proposée par ce formalisme. Au cours des dernières années, I-SCORE a été utilisé avec succès pour la composition et l’exécution des spectacles et des expositions interactives. Néanmoins, ces applications et les applications émergentes telles queles jeux vidéo et les installations muséales interactives, de plus en plus exigent deux caractéristiques que la version stable actuelle de I-SCORE ainsi que son modèle sous-jacent ne supportent pas : (1)des structures de contrôle flexibles comme des conditionnelles et des boucles ; et (2) des mécanismes pour la vérification automatique de scénarios.Dans cette thèse, nous présentons deux modèles formels pour la composition et la vérification automatique de scénarios interactifs multimédia avec des choix interactifs, i.e., des scénarios où l’interprète ou le système peut prendre des décisions au sujet de leur état d’exécution avec un certain degré de liberté définie par le compositeur.Dans notre première approche, nous définissons un nouveau langage de programmation appelé REACTIVEIS dont les programmes sont définis comme des arbres représentant l’aspect hiérarchique des scénarios interactifs et dont les noeuds contiennent les conditions nécessaires pour démarrer et arrêter les objets temporels (TOS). En outre, nous définissons une sémantique opérationnelle basé sur des arbres marqués, contenant dans leurs noeuds, les informations sur le début et la fin de chaque TO. Nous définissons également une interprétation déclarative de REACTIVEIS comme formules de la logique linéaire intuitionniste avec sous exponentiels (SELL). Nous montrons que cette interprétation est adéquate : les dérivations dans la logique correspondent à des traces du programme et vice-versa.Dans notre deuxième approche, nous présentons un système basé sur des Automates Temporisés.Dans le système proposé, nous modélisons des scénarios interactifs comme un réseau d’automates temporisés et les étendons avec des points interactifs gardés par des conditions, permettant ainsi la spécification de comportements avec branchements. Par ailleurs, nous profitons des outils matures et efficaces pour simuler et vérifier automatiquement des scénarios modélisés comme des automates temporisés. Dans notre système, les scénarios peuvent être synthétisés dans un matériel reconfigurable afin de fournir une faible latence et l’exécution en temps réel.Dans cette thèse, nous explorons également une nouvelle façon de définir et mettre en oeuvre des scénarios interactifs, visant à un modèle plus dynamique en utilisant le langage réactif REACTIVEML.Enfin, nous présentons une extension des scénarios interactifs utilisant des réseaux de Petri colorés(CPN) qui vise à traiter des données complexes, en particulier, les données statiques et dynamiques de flux audio. / Interactive multimedia deals with the computer-based design of scenarios consisting of multimediacontent that interacts with external actions and those of the performer (e.g., multimedialive-performance arts, interactive museum installations, and video games). The multimedia content is structured in a spatial and temporal order according to the author’s requirements. Therefore, thepotentially high complexity of these scenarios requires adequate specification languages for theircomplete description and verification.Interactive scores is a formalism which has been proposed as a model for composing and performing interactive multimedia scenarios. In addition, an inter-media sequencer, called I-SCORE, hasbeen developed following the Petri Net semantics proposed by this formalism. During the last years,I-SCORE has been used successfully for the composition and performance of live performances and interactive exhibitions. Nevertheless, these applications and emergent applications such as videogames and interactive museum installations, increasingly demand two features that the current stable version of I-SCORE as well as its underlying model do not support: (1) flexible control structures such as conditionals and loops; and (2) mechanisms for the automatic verification of scenarios.In this dissertation we present two formal models for composition and automatic verification of multimedia interactive scenarios with interactive choices, i.e., scenarios where the performer or thesystem can take decisions about their execution state with a certain degree of freedom defined bythe composer.In our first approach, we define a novel programming language called REACTIVEIS. This language extends the full capacity of temporal organization of interactive scenarios by allowing the composerto use a defined logical system for the specification of the starting and stopping conditions of temporal objects (TOs). REACTIVEIS programs are formally defined as tree-like structures representing the hierarchical aspect of interactive scenarios and whose nodes contain the conditions needed to startand stop the TOs. Moreover, we define an operational semantics based on labeled trees, containing in their nodes, the information about the start and stop times of each TO.We show that this operational semantics offers an intuitive yet precise description of the behavior of interactive scenarios.We also endowed REACTIVEIS with a declarative interpretation as formulas in Intuitionistic LinearLogic with Subexponentials (SELL). We shall show that such interpretation is adequate: derivations in the logic correspond to traces of the program and vice-versa. Hence, we can use all the meta-theory of Intuitionistic Linear Logic (ILL) to reason about interactive scenarios and develop tools for theverification and analysis of interactive scenarios.In our second approach, we present a Timed Automata (TA) based framework. In the proposed framework, we model interactive scenarios as a network of timed automata and extend them with interactive points (IPs) guarded by conditions, thus allowing for the specification of branching behaviors.Moreover, we take advantage of the mature and efficient tools for TA to simulate and automatically verify scenarios. In our framework, scenarios can be synthesized into a reconfigurable hardware in order to provide a low-latency and real-time execution by taking advantage of the physical parallelism,low-latency, and high-reliability of these devices. Furthermore, we implemented a tool to systematically construct bottom-up TA models from the composition environment of I-SCORE. Doing that, we provide a friendly and specialized environment for composing and automatic verification of interactive scenarios. Finally, we present an extension of interactive scenarios using Colored Petri Nets (CPNs) thataims to handle complex data, in particular, dynamic and static data audio streams. [...]
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Tecnologias adaptativas aplicadas na flexibilização de redes neurais artificiais e redes de Petri. / Adaptive technologies applied to flexibilization of artificial neural networks and Petri nets.Guibu, Haroldo Issao 15 December 2017 (has links)
O objetivo deste trabalho é o estudo das tecnologias adaptativas aplicadas às redes neurais artificiais e às redes de Petri. Além disso, uma metodologia é proposta para estas aplicações a partir da definição de uma rede de Petri colorida adaptativa. Inicialmente, as redes neurais artificiais são estudadas do ponto de vista da extração de regras. Uma das críticas recorrentes às redes neurais artificiais é a característica de \"caixa preta\" das soluções, significando que as soluções escondem o mecanismo de funcionamento, deixando em dúvida a razão de seu funcionamento. A extração de regras a partir das redes neurais artificiais objetiva apresentar uma solução equivalente baseada em regras que para os especialistas em uma determinada área seja mais inteligível ou transparente. Outro ponto importante é a inserção de regras nas redes neurais artificiais. Esta inserção é possível a partir da versão baseada em regras das redes neurais artificiais. Um especialista humano em uma área muitas vezes cria um conjunto de regras que o auxiliam na compreensão do problema. Se estas regras forem inseridas ao conjunto de regras obtidas através dos dados, o novo conjunto de regras conterá ao mesmo tempo o conhecimento humano e o conhecimento extraído dos dados. As tecnologias adaptativas de extração e inserção de regras tornam as soluções mais flexíveis. As redes de Petri são, em certo sentido, complementares às redes neurais artificiais pois foram criadas para tratar os \"Sistemas a Eventos Discretos\" ou sistemas sequenciais, enquanto que as redes neurais artificiais possuem uma natureza combinatória. Muitas extensões foram propostas à redes de Petri ao longo dos anos e entre estas extensões aparecem associações de redes de Petri e redes neurais artificiais. Nestas associações, muitas técnicas desenvolvidas para as redes neurais artificiais foram incorporadas às redes de Petri como, por exemplo, as diversas formas de aprendizado. Utilizando a característica das redes de Petri de modelagem de sistemas sequenciais, a fase de treinamento das redes neurais artificiais pode ser controlada pela rede de Petri. Neste trabalho, a incorporação de regras à rede de Petri é examinada assim como a sua aplicação a sistemas de apoio à decisão e a sistemas de manufatura flexível. / The objective of this work is the study of adaptive technologies applied to artificial neural networks and Petri nets. In addition, a methodology is proposed for these applications from the definition of an adaptive color Petri net. Initially, artificial neural networks are studied from the point of view of rule extraction. One of the recurring criticisms of artificial neural networks is the \"black box\" feature of the solutions, meaning that the solutions hide the working mechanism, casting doubt on the reason for its operation. The extraction of rules from the artificial neural networks aims to present an equivalent solution based on rules that for the experts in a given area is more intelligible or transparent. Another important point is the insertion of rules in artificial neural networks. This insertion is possible from the rule-based version of artificial neural networks. A human expert in an area often creates a set of rules that aid in understanding the problem. If these rules are inserted into the set of rules obtained from the data, the new set of rules will contain at the same time the human knowledge and the knowledge extracted from the data. Adaptive rule extraction and insertion technologies make solutions more flexible. Petri nets are, in a sense, complementary to artificial neural networks as they were designed to treat \"Discrete Event Systems\" or sequential systems, while artificial neural networks have a combinatorial nature. Many extensions have been proposed to the Petri nets over the years and among these extensions appear associations of Petri nets and artificial neural networks. In these associations, many techniques developed for artificial neural networks were incorporated into Petri nets, such as the various forms of learning. Using the Petri nets feature of sequential modeling, the training phase of artificial neural networks can be controlled by the Petri net. In this work, the incorporation of rules into the Petri net is examined as well as its application to decision support systems and flexible manufacturing systems.
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Arquitetura para descoberta de equipamentos em processos de manufatura com foco na indústria 4.0. / Architecture to discover equipment in manufacturing processes focused on industry 4.0.Pisching, Marcos André 08 December 2017 (has links)
A Indústria 4.0, ou quarta revolução industrial, é o atual cenário industrial que estabelece um novo paradigma para os sistemas de produção. A indústria 4.0 é compreendida como a implementação da fábrica inteligente que opera de forma mais autônoma e com menor intervenção humana, cujo propósito é prover serviços e produtos inteligentes que atendam às necessidades individuais dos consumidores. A Indústria 4.0 está amparada nos sistemas ciber-físicos (CPS) e na Internet das Coisas (IoT). Neste cenário máquinas e produtos se comunicam entre si visando automatizar os processos industriais por meio de informações individuais obtidas em tempo real durante os processos de manufatura. No entanto, a Indústria 4.0 e as pesquisas em torno desse assunto ainda são muito recentes e requerem mais investigações no que diz respeito às arquiteturas que suportem a sua implementação, entre elas a comunicação entre produtos e máquinas. Neste quesito, recentemente foi proposto o modelo de arquitetura de referência para a Indústria 4.0 (RAMI 4.0) com o objetivo de nortear a implementação deste tipo de sistema. Contudo, o RAMI 4.0 ainda requer esforços no campo da pesquisa sob diferentes aspectos, entre eles a integração vertical de recursos do sistema de produção. Neste sentido, este trabalho objetiva apresentar uma arquitetura para a descoberta de equipamentos para processar operações conforme as necessidades dos produtos. A arquitetura foi projetada em camadas baseadas no RAMI 4.0 para prover componentes que permitam a comunicação entre equipamentos e produtos, e um mecanismo similar ao sistema de nomes de domínios (DNS - Domain Name System) para realizar a descoberta de equipamentos para processar uma determinada operação. Nessa arquitetura as informações dos equipamentos são armazenadas em uma estrutura organizada hierarquicamente para auxiliar o serviço de descoberta, e os produtos possuem informações das operações necessárias para o processo de manufatura. Para garantir a eficácia do funcionamento dos componentes e suas interações, é necessário a verificação e validação por meio de métodos formais. Neste trabalho a verificação e validação é realizada por meio da técnica PFS (Production Flow Schema)/RdP (Rede de Petri). Por fim, a arquitetura é aplicada em um sistema de produção modular para demonstrar a sistemática de implementação e a sua efetividade. / The Industry 4.0, also known as fourth industrial revolution, is the current industrial scenario that sets a new paradigm for production systems. The Industry 4.0 can be understood as the implementation of the smart factory that operates more autonomously and with less human intervention. The purposes of it is to provide smart products and services that meet the consumer individual needs. The Industry 4.0 is supported by cyber-physical systems (CPS) and Internet of Things (IoT). In this scenario machines and products communicate with each other to automate industrial processes through individual information that are obtained in real time during manufacturing processes. However, the researches around this issue are still very recent and require further investigations with regard of to the architectures that support its implementation, including communication between products and equipment. Taking into account this problem, a Reference Architectural Model for Industry 4.0 (RAMI 4.0) was recently proposed with the purpose to guide the implementation of this system type. However, the RAMI 4.0 still requires efforts in different aspects, including the vertical integration of resources of the production systems. In this sense, this work aims to present an architecture for the discovery of equipment to process operations according to the product needs. The architecture was designed based on layers of the RAMI 4.0 to provide components that allow communication between equipment and products and a Web Service that offer a mechanism similar to the Domain Name System (DNS) to locate equipment to process a required operation. In this architecture the capable operations supported by the equipment are stored in a structure organized hierarchically to aid the discovery service, and the products have information of the operation required for the manufacturing process. In order to guarantee the effectiveness of the component functionalities and their interactions it is necessary to verify and validate them by formal methods. In this work the Production Flow Schema (PFS)/Petri Net (PN) technique is used to develop the conceptual and functional modeling of the architecture. Finally the architecture is applied in a modular production system to demonstrate its implementation systematics and its effectiveness.
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Modelagem de sistemas flexíveis de movimentação de materiais através de redes de Petri interpretadas. / Modeling flexible systems of materials movement using interpreted Petri nets.Fabrício Junqueira 02 February 2001 (has links)
Os sistemas de manufatura há muito vêm sendo objeto de interesse por profissionais e pesquisadores devido à busca de melhores técnicas visando o aumento da produtividade bem como pelo aumento da competitividade empresarial ao longo dos anos. Dentre seus componentes, o sistema de movimentação de materiais merece atenção especial pois, apesar de não aumentar o valor do produto, é responsável por manter o fluxo de materiais entre máquinas, células de manufatura, centros de custos ou mesmo entre empresas, que é imprescindível para qualquer sistema produtivo. Neste contexto, o presente trabalho propõe uma metodologia para a modelagem de sistemas flexíveis de movimentação de materiais e partes em ambiente fabril, focando-se em sistemas cuja movimentação possa ser realizada por VATs (Veículos Autônomos de Transporte). Considerando-se o sistema de movimentação de materiais como sendo um sistema a eventos discretos (SEDs), pode-se empregar técnicas derivadas das Redes de Petri como o PFS (Production Flow Schema) e o E-MFG (Enhanced Mark Flow Graph) na modelagem de tais sistemas. Para tanto, foram introduzidos conceitos de orientação a objetos ao E-MFG de forma a ampliar sua capacidade de modelagem, possibilitando a migração de um paradigma de modelagem orientada a processos para um de modelagem híbrida orientada a processos e a objetos. Como estudo de caso, apresenta-se a modelagem de uma simplificação do sistema de movimentação de materiais da Mercedes Benz do Brasil, situada em São Bernardo do Campo, São Paulo, para a qual se aplica a metodologia proposta. / Manufacturing systems have been object of interest of many professionals and researchers through the years due to the search of better methods for raising goods productivity and managerial competitiveness. Among its components, the material movement system deserves special attention because even not increasing the product value, it is responsible for keeping the flow of materials between machines, manufacturing cells, cost centers and also between companies, which is indispensable for any productive system. In this context, this work proposes a methodology for modeling flexible systems for materials and parts movement in the industrial environment, focusing on systems whose movement can be performed by AGVs (Autonomous Guided Vehicles). Considering the materials movement system as a Discrete Event System (DES), techniques derived from Petri Nets as PFS (Production Flow Schema) and E-MFG (Enhanced Mark Flow Graph) can be used for modeling those systems. To this purpose, concepts of object orientation are introduced to E-MFG in order to increase its modeling capacity, allowing the migration from the process oriented modeling paradigm to an hybrid object and process oriented modeling. A simplification of the materials movement system of the plant of "Mercedes Benz do Brasil", which is located in São Bernado do Campo, São Paulo, was used as a study case to illustrate the methodology presented.
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