Dissertations / Theses on the topic 'Stochatic Time Petri Net'
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Rau, de Almeida Callou Gustavo. "Energy consumption and execution time estimation of embedded system applications." Universidade Federal de Pernambuco, 2009. https://repositorio.ufpe.br/handle/123456789/1877.
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Previous issue date: 2009Nos últimos anos, a redução do consumo de energia das aplicações dos sistemas embarcados tem recebido uma grande atenção da comunidade científica, visto que, como o tempo de resposta e o baixo consumo de energia são requisitos conflitantes, esses estudos tornam-se altamente necessários. Nesse contexto, é proposta uma metodologia aplicada nas fases iniciais de projeto para dar suporte às decisões relativas ao consumo de energia e ao desempenho das aplicações desses dispositivos embarcados. Al´em disso, esse trabalho propõe modelos temporizados de eventos discretos que são avaliados através de uma metodologia de simulção estocástica com o objetivo de representar diferentes cenários dos sistemas com facilidade. Dessa forma, para cada cenário ´e preciso decidir o n´umero máximo de simulações e o tamanho de cada rodada da simulação, onde ambos os fatores podem impactar no desempenho para se obter tais estimativas. Essa metodologia considera também, um modelo intermediário que representa a descrição do comportamento do sistema e, é através desse modelo que cenários são analisados. Esse modelo intermediário ´e baseado em redes de Petri coloridas temporizadas que permitem não somente a anáise do software, mas também fornece suporte a um conjunto de métodos bem estabelecidos para verificações de propriedades. É nesse contexto que o software, ALUPAS, responsável por estimar o consumo de energia e o tempo de execução dos sistemas embarcados é apresentado. Por fim, um caso de estudo real, assim como tamb´em, exemplos customizados são apresentados com a finalidade de mostrar a aplicabilidade desse trabalho, onde usuários não especializados não precisam interagir diretamente com o formalismo de redes de Petri.
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Wiley, Richard Paul. "Performance analysis of Stochastic Timed Petri Nets." Thesis, Massachusetts Institute of Technology, 1985. http://hdl.handle.net/1721.1/15002.
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Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1986.MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING
Bibliography: leaves 305-310.
by Richard Paul Wiley.
Sc.D.
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Rogge-Solti, Andreas, Laura Vana, and Jan Mendling. "Time Series Petri Net Models - Enrichment and Prediction." CEUR Workshop Proceedings, 2015. http://epub.wu.ac.at/5394/1/paper8.pdf.
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Operational support as an area of process mining aims to predict the
temporal performance of individual cases and the overall business process. Although
seasonal effects, delays and performance trends are well-known to exist
for business processes, there is up until now no prediction model available that
explicitly captures this. In this paper, we introduce time series Petri net models.
These models integrate the control flow perspective of Petri nets with time series
prediction. Our evaluation on the basis of our prototypical implementation demonstrates
the merits of this model in terms of better accuracy in the presence of time
series effects.
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Tabacchi, Peter J. "Analysis of engineer C2 as modeled by stochastic, timed attributed Petri Nets." Thesis, Monterey, California : Naval Postgraduate School, 1990. http://handle.dtic.mil/100.2/ADA238339.
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Thesis (M.S. in Operations Research)--Naval Postgraduate School, September 1990.Thesis Advisor(s): Caldwell, William J. ; Read, Robert R. Second Reader: Whitaker, Lyn R. "September 1990." Description based on title screen as viewed on December 21, 2009. DTIC Identifier(s): Command And Control Systems, Timed Petri Nets, Attributed Petri Nets, Land Warfare, Thesis. Author(s) subject terms: Land Warfare, Military Planning, Military Science, Petri Nets, Command and Control, Combat Engineers. Includes bibliographical references (p. 80). Also available in print.
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Cortés, Luis Alejandro. "A Petri Net based Modeling and Verification Technique for Real-Time Embedded Systems." Licentiate thesis, Linköping University, Linköping University, ESLAB - Embedded Systems Laboratory, 2001. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-5751.
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Embedded systems are used in a wide spectrum of applications ranging from home appliances and mobile devices to medical equipment and vehicle controllers. They are typically characterized by their real-time behavior and many of them must fulfill strict requirements on reliability and correctness.
In this thesis, we concentrate on aspects related to modeling and formal verification of realtime embedded systems.
First, we define a formal model of computation for real-time embedded systems based on Petri nets. Our model can capture important features of such systems and allows their representations at different levels of granularity. Our modeling formalism has a welldefined semantics so that it supports a precise representation of the system, the use of formal methods to verify its correctness, and the automation of different tasks along the design process.
Second, we propose an approach to the problem of formal verification of real-time embedded systems represented in our modeling formalism. We make use of model checking to prove whether certain properties, expressed as temporal logic formulas, hold with respect to the system model. We introduce a systematic procedure to translate our model into timed automata so that it is possible to use available model checking ools. Various examples, including a realistic industrial case, demonstrate the feasibility of our approach on practical applications.
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Xia, Fei. "Supporting the MASCOT method with Petri net techniques for real-time systems development." Thesis, King's College London (University of London), 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325515.
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TAVARES, Eduardo Antônio Guimarães. "A time Petri net based approach for software synthesis in Hard Real-Time embedded systems with multiple processors." Universidade Federal de Pernambuco, 2006. https://repositorio.ufpe.br/handle/123456789/2589.
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Previous issue date: 2006Atualmente, sistemas embarcados são ubíquos. Em outras palavras, eles estão em todos os lugares. Desde utilitários domésticos (ex: fornos microondas, refrigeradores, videocassetes, máquinas de fax, máquinas de lavar roupa, alarmes) até equipamentos militares (ex: mísseis guiados, satélites espiões, sondas espaciais, aeronaves), nós podemos encontrar um sistema embarcado. Desnecessário afirmar que a vida humana tem se tornado mais e mais dependente desses sistemas. Alguns sistemas embarcados são classificados como sistemas de tempo real, onde o comportamento correto depende não somente da integridade dos resultados, mas também nos tempos em que tais resultados são produzidos. Em sistemas embarcados de tempo real críticos, se as restrições temporais não forem satisfeitas, as conseqüências podem ser desastrosas, incluindo grandes danos aos equipamentos ou mesmo perdas de vidas humanas. Devido a tarefas que possuem alta taxa de utilização de processador, alguns sistemas embarcados (ex: dispositivos médicos) precisam ser compostos de mais de um processador para obter performance aceitável e, no caso de sistemas embarcados de tempo real críticos, para satisfazer as restrições temporais críticas. Entretanto, questões adicionais precisam ser consideradas para lidar com um ambiente multiprocessado, tal como comunicação entre processadores e sincronização. Nessa dissertação, um método de síntese de software baseado no formalismo matemático redes de Petri com tempo é apresentado para lidar com sistemas embarcardos de tempo real críticos com múltiplos processadores. A abordagem inicia a partir de uma especificação (usualmente composta de tarefas concorrentes e comunicantes) e automaticamente gera o código fonte de um programa considerando: (i) as funcionalidades e restrições; e (ii) o suporte operacional para execução das tarefas em um ambiente multiprocessado. Síntese de software é uma alternativa para sistemas operacionais especializados para dar suporte a execução de um programa. Sistemas operacionais são usualmente genéricos e podem introduzir atrasos no tempo de execução, e ao mesmo tempo produzir alto consumo de memória. Por outro lado, a síntese de software é uma alternativa de projeto, dado que este método automaticamente gera o código fonte do programa, satisfazendo a funcionalidade, as restrições especificadas, o suporte para execução, e a minimização dos atrasos e uso de memória
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Aghanoori, Navid. "Real-time Power Management of Renewable Microgrid based on IEC 61850 Communication Protocol Using Adaptive Intelligent Petri Net." Thesis, Curtin University, 2020. http://hdl.handle.net/20.500.11937/79919.
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My personal interest and practical experience in renewable industry encouraged me to study my PhD in relation to the cascaded interaction of the microgrid power management, the stability of microgrid and the communication delays within microgrid’s control system. This PhD proposes a real-time power management platform equipped with an adaptive intelligent Petri Net and a new data class of IEC 61850 standard to optimise the cost of microgrid operation while maintaining its stability.
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Baldellon, Olivier. "Supervision en ligne de propriétés temporelles dans les systèmes distribués temps-réel." Phd thesis, Toulouse, INPT, 2014. http://oatao.univ-toulouse.fr/13299/1/baldellon.pdf.
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Les systèmes actuels deviennent chaque jour de plus en plus complexe; à la distribution s’ajoutent les contraintes temps réel. Les méthodes classiques en charge de garantir la sûreté de fonctionnement, comme le test, l’injection de fautes ou les méthodes formelles ne sont plus suffisantes à elles seules. Afin de pouvoir traiter les éventuelles erreurs lors de leur apparition dans un système distribué donné, nous désirons mettre en place un programme, surveillant ce système, capable de lancer une alerte lorsque ce dernier s’éloigne de ses spécifications ; un tel programme est appelé superviseur (ou moniteur). Le fonctionnement d’un superviseur consiste simplement à interpréter un ensemble d’informations provenant du système sous forme de message, que l’on qualifiera d’évènement, et d’en déduire un diagnostic. L’objectif de cette thèse est de mettre un place un superviseur distribué permettant de vérifier en temps réel des propriétés temporelles. En particulier nous souhaitons que notre moniteur soit capable de vérifier un maximum de propriétés avec un minimum d’information. Ainsi notre outil est spécialement conçu pour fonctionner parfaitement même si l’observation est imparfaite, c’est-à-dire, même si certains évènements arrivent en retard ou s’ils ne sont jamais reçus. Nous avons de plus cherché à atteindre cet objectif de manière distribuée pour des raisons évidentes de performance et de tolérance aux fautes. Nous avons ainsi proposé un protocole distribuable fondé sur l’exécution répartie d’un réseau de Petri temporisé. Pour vérifier la faisabilité et l’efficacité de notre approche, nous avons mis en place une implémentation appelée Minotor qui s’est révélée avoir de très bonnes performances. Enfin, pour montrer l’expressivité du formalisme utilisé pour exprimer les spécifications que l’on désire vérifier, nous avons détaillé un ensemble de propriétés sous forme de réseaux de Petri à double sémantique introduite dans cette thèse (l’ensemble des transitions étant partitionné en deux catégories de transitions, chacune de ces parties ayant sa propre sémantique).
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Ďuriš, Anton. "Simulace distribuovaných systémů." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2021. http://www.nusl.cz/ntk/nusl-442811.
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This thesis is focused on distributed systems modeling using Petri nets. Distributed systems are increasingly being implemented in applications and computing systems, where their task is to ensure sufficient performance and stability for a large number of its users. When modeling a distributed systems, stochastic behavior of Petri nets is important, which will provide more realistic simulations. Therefore, this thesis focuses mainly on timed Petri nets. The theoretical part of this thesis summarizes distributed systems, their properties, types and available architectures, as well as Petri nets, their representation, types and the principle of an operation. In the practical part, two models were implemented, namely a horizontally scaled web application divided into several services with a distributed database and a large grid computing system, more precisely the BOINC platform with the Folding@home project. Both models were implemented using the PetNetSim library of Python. The goal of this thesis is to perform simulations on the created models for different scenarios of their behavior.
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Zhang, Yingying. "Algorithms and Data Structures for Efficient Timing Analysis of Asynchronous Real-time Systems." Scholar Commons, 2013. http://scholarcommons.usf.edu/etd/4622.
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This thesis presents a framework to verify asynchronous real-time systems based on model checking. These systems are modeled by using a common modeling formalism named Labeled Petri-nets(LPNs).
In order to verify the real-time systems algorithmically, the zone-based timing analysis method is used for LPNs. It searches the state space with timing information (represented by zones). When there is a high degree of concurrency in the model, firing concurrent enabled transitions in different order may result in different zones, and these zones may be combined without affecting the verification result. Since the zone-based method could not deal with this problem efficiently, the POSET timing analysis method is adopted for LPNs. It separates concurrency from causality and generates an exactly one zone for a single state. But it needs to maintain an extra POSET matrix for each state. In order to save time and memory, an improved zone-based timing analysis method is introduced by integrating above two methods. It searches the state space with zones but eliminates the use of the POSET matrix, which generates the same result as with the POSET method. To illustrate these methods, a circuit example is used throughout the thesis.
Since the state space generated is usually very large, a graph data structure named multi-value decision diagrams (MDDs) is implemented to store the zones compactly. In order to share common clock value of dierent zones, two zone encoding methods are described: direct encoding and minimal constraint encoding. They ignore the unnecessary information in zones thus reduce the length of the integer tuples. The effectiveness of these two encoding methods is demonstrated by experimental result of the circuit example.
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Bourdil, Pierre-Alain. "Contribution à la modélisation et la vérification formelle par model checking - Symétries pour les Réseaux de Petri temporels." Thesis, Toulouse, INSA, 2015. http://www.theses.fr/2015ISAT0041/document.
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Cette thèse traite de la vérification formelle de systèmes critiques où la correction du système dépend du respect des contraintes temporelles. La première partie étudie la modélisation et la vérification formelle par model-checking de systèmes temps réel dans le contexte de l’industrie aéronautique et spatiale. La deuxième partie décrit notre méthode d’exploitation des symétries pour les réseaux de Petri temporels. Nous définissons un opérateur de composition symétrique pour la construction de réseaux. Puis nous proposons des solutions pour la construction d’espaces d’états quotients par la relation d’équivalence induite par les symétries. Notre méthode s’applique aux réseaux de Petri, temporels ou non. A notre connaissance il s’agit de la première méthode applicable aux réseaux de Petri temporels. Des résultats expérimentaux encourageants sont présentésThis thesis deals with formal verification of critical systems where the system’s correction depends on compliance with time constraints. The first part studies the formal modeling and verification by model-checking of realtime systems in the context of the aerospace industry. The second part describes our method for symmetry reduction of Time Petri Net. We define a symmetric composition operator for building Net. Then we present our solution for construction of quotients of the state spaces by the equivalence relation induced by symmetries. Our method applies to Petri nets, temporal or not, but to our knowledge this is the first methodology for Time Petri Nets. Encouraging experimental results are presented
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Masiero, Alessandro. "The role of time in biological systems: a computational analysis ranging from molecular dynamics to biological network simulations." Doctoral thesis, Università degli studi di Padova, 2015. http://hdl.handle.net/11577/3424021.
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Time is the main character of this thesis, and it has been used in many ways. Starting from molecular dynamics simulations to biological networks, time has been analysed under different light and roles. The main subjects characterizing this work are Von Hippel-Lindau syndrome and circadian rhythm, although a method for molecular dynamics simulations trajectory analysis is presented at the end. Several works are presented here, analysing different aspects of protein dynamics as well as pathway alterations depending on the time coordinate. The first work analyses the interaction between protein Von Hippel-Lindau (pVHL) and its main interactor, Hipoxya Inducibe Factor 1α by means of molecular dynamics simulations, investigating on a non-conventional proline hydroxylation event. As a result, we obtained that a specific hydrogen bond network rearrangement and improved electrostatic energy for hydroxylated P567 appear to be compatible with an increase in HIF-1α binding affinity. Sequence analysis also confirms P567 to be vastly conserved during evolution, indicating a possible role for this alternative, PHD-3 driven, post translational modification in pVHL–HIF-1α complex formation. The second work dealt with the same main subject, but investigated through biological network simulations, particularly with Petri net models. In this work, we presented a novel manually curated Petri Net (PN) model of the main pVHL functional pathways. The model was built using functional information derived from the literature. It includes all major pVHL functions and is able to credibly reproduce VHL syndrome at the molecular level. The reliability of the PN model also allowed in silico knockout experiments, driven by previous model analysis. Interestingly, PN analysis suggests that the variability of different VHL manifestations is correlated with the concomitant inactivation of different metabolic pathways. In the third work, investigating the structural role of flavin-adenine-dinucleotide (FAD) through molecular dynamics simulations, we analyzed the Drosophila melanogaster Cryptochrome crystal structure, elucidating how this large co-factor within the receptor could be crucial for CRY structural stability. The co-factor appears indeed to improve receptor motility, providing steric hindrance. Moreover, multiple sequence alignments revealed that conserved motifs in the C-terminal tail could be necessary for functional stability. The fourth work focused on the sequence impact on the modern folds. We shuffled the sequences of 10 natural proteins and obtained 40 different and apparently unrelated folds. Our results suggest that shuffled sequences are sufficiently stable and may act as a basis to evolve functional proteins. The common secondary structure of modern proteins is well represented by a small set of permuted sequences, which also show the emergence of intrinsic disorder and aggregation-prone stretches of the polypeptide chain. The last work presented here is a method to quickly analyse molecular dynamics simulations trajectories. The complexity related to their interpretation and analysis is still one of the major challenges for most users. In this work we introduce RING MD, which is able to identify the most important frames (PDB structures) and key residues that cause different conformers transitions, providing a simple interpretation useful for non-expert users. Comparison with the classical analysis of three MD simulations, Ubiquitin, T4 Lysozyme and T4 Glutaredoxin, confirmed RING MD results and effectiveness.
At the end, time should not be considered simply as something entraining the environment, it is what indeed modifies systems and environment. Different systems simply change in different ways, because of different mechanisms, but the main driving force should always be considered time.Il tempo è soggetto principale di questa tesi, ed è stato utilizzato in molti modi. A partire da simulazioni di dinamica molecolare a reti biologiche, il tempo è stato analizzato in diversi modi e con diversi ruoli. I principali temi che caratterizzano questo lavoro sono la sindrome di Von Hippel-Lindau e il ritmo circadiano, anche se un metodo di analisi di traiettorie di simulazioni di dinamica molecolare è presentato alla fine. Diversi lavori sono presentati qui, analizzando diversi aspetti della dinamica delle proteine, nonché alterazioni di pathway dipendenti dalla coordinata temporale. Il primo lavoro analizza l'interazione tra proteina Von Hippel-Lindau (pVHL) e il suo interattore principale, Hipoxya Inducibe Factor 1α mediante simulazioni di dinamica molecolare, indagando su un evento di idrossilazione di una prolina non convenzionale. Come risultato, abbiamo ottenuto che uno specifico riarrangiamento di una rete di legami a idrogeno e un incremento di affinità elettrostatica nel sistema contenente la P567 idrossilata sembrano essere compatibili con un aumento di affinità di legame per HIF-1α. Analisi di sequenza confermano anche che P567 è notevolmente conservata durante l'evoluzione, indicando un possibile ruolo per questa modificazione post trasduzionale dipendente dalla PHD-3, nella formazione del complesso pVHL-HIF-1α. Il secondo lavoro affronta lo stesso soggetto principale, ma studiato attraverso simulazioni di reti biologiche, in particolare con reti di Petri. In questo lavoro, abbiamo presentato in un modello curato manualmente di Petri Net (PN) I principali pathway funzionali di pVHL. Il modello è stato costruito utilizzando informazioni funzionali derivate dalla letteratura. Include tutte le funzioni principali pVHL ed è in grado di riprodurre in modo credibile la sindrome VHL a livello molecolare. L'affidabilità del modello PN ha permesso anche esperimenti di knockout in silico, guidata da precedenti analisi del modello. È interessante notare che l’analisi della PN suggerisce che la variabilità delle diverse manifestazioni VHL è correlata con l'inattivazione concomitante di diverse vie metaboliche. Nel terzo lavoro, concernente il ruolo strutturale del flavin-adenina-dinucleotide (FAD) attraverso simulazioni di dinamica molecolare, abbiamo analizzato la struttura cristallografica di Criptocromo di Drosophila melanogaster, per chiarire come questo co-fattore nei recettore potrebbe essere cruciale per la stabilità strutturale della proteina. Il co-fattore sembra promuovere la motilità del recettore, fornendo un effetto sterico. Inoltre, allineamenti multipli di sequenza hanno rivelato che i motivi conservati nella coda C-terminale potrebbero essere necessari per la stabilità funzionale. Il quarto lavoro concerne l'impatto che diverse sequenze hanno sui fold moderni. Abbiamo mischiato le sequenze di 10 proteine naturali e ottenuto 40 diversi e apparentemente non collegati fold. I nostri risultati suggeriscono che le sequenze ottenute sono sufficientemente stabili e possono fungere da base per evolvere proteine funzionali. La struttura secondaria comune di proteine moderne è ben rappresentata da un piccolo insieme di sequenze permutate che sottolineano anche l'emergere di disordine intrinseco e tratti di segmenti peptidici pro-aggregazione. L'ultimo lavoro qui presentato è un metodo per analizzare rapidamente traiettorie di simulazioni di dinamica molecolare. La complessità legata alla loro interpretazione e l'analisi sono ancora tra le principali sfide per la maggior parte degli utenti. In questo lavoro introduciamo RING MD, che è in grado di identificare i frame più importanti (strutture PDB) e residui chiave che causano transazioni tra diversi conformeri, fornendo una fonte di semplice interpretazione utile per gli utenti non esperti. Il confronto con l'analisi classica di tre simulazioni, ubiquitina, lisozima e glutaredossina di batteriofago T4, conferma l’efficacia di RING MD. Alla fine, il tempo non dovrebbe essere considerato semplicemente come spettatore passivo, ma effettivamente parte attiva nella modifica di sistemi e dell'ambiente. Diversi sistemi mutano in maniera diversa, a causa di diversi meccanismi, ma la principale forza motrice deve sempre essere considerata il tempo.
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Zenié, Alexandre. "Les reseaux de petri stochastiques colores : application a l'analyse des systemes repartis en temps reel." Paris 6, 1987. http://www.theses.fr/1987PA066672.
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Application de la theorie des reseaux de petri stochastiques colores a l'analyse de certains problemes lies aux systemes repartis en temps reel (controle reparti, prevention d'interblocage, bases de donnees reparties, messagerie, interconnexions et acces aux reseaux locaux). Ces applications ont ete possibles grace au developpement d'un logiciel, applicable aux modeles markoviens
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Hefka, Lukáš. "Plánování a rozvrhování." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2009. http://www.nusl.cz/ntk/nusl-236744.
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This thesis deals with optimization problems of planning and scheduling. There are using genetic algorithms which are inspired by evolution process. Main work is familiar with the problem of planning and scheduling, genetic algorithm and Petri nets. This knowledge was used to create applications that would with the use of genetic algorithms was able to solve planning problems and the resulting plans would be represented the Time Petri Net. In conclusion of the this thesis are presented obtained results and examples of field use.
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Rocha, Loures de Freitas Eduardo. "Surveillance et diagnostic des phases transitoires des systèmes hybrides basés sur l'abstraction des dynamiques continues par réseau de Pétri temporel flou." Toulouse 3, 2005. http://www.theses.fr/2006TOU30022.
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Les systèmes de surveillance et de supervision jouent un rôle majeur pour la sécurité des installations industrielles et la disponibilité des équipements. Signaler le plus tôt possible à l'opérateur les écarts détectés par rapport au comportement nominal prévu est fondamental pour la mise en œuvre des actions préventives et correctives sur le procédé. Certains types d'installations tels que les procédés chimiques et de traitement par lots (batch systems) présentent une grande complexité pour la commande/surveillance en raison de leur caractère hybride (aspects continus et discrets étroitement liés), du nombre de variables mis en jeu et de la complexité de leurs relations. Cette complexité est accentuée par la nécessité de nombreux changements de modes opératoires qui conduisent à de nombreuses phases transitoires. La surveillance de ces phases transitoires est délicate. Le nombre élevé de variables à considérer rend difficile l'interprétation du comportement du procédé. En cas de défaut, un diagnostic devient alors une tâche complexe. Les écarts, même marginaux, par rapport au comportement nominal souhaité doivent être surveillés de façon à avertir l'opérateur sur des évolutions non prévues qui peuvent aboutir à une défaillance. Les écarts marginaux peuvent indiquer un dysfonctionnement qui dégénère lentement ou encore une conduite inadéquate de l'opérateur ou du système de pilotage. Pour faire face à la complexité, le système de commande/surveillance est hiérarchisé selon la hiérarchie procédurale proposée par la norme ISA88. Notre démarche de surveillance et diagnostic se situe à deux niveaux hauts de cette hiérarchie procédurale : i) au niveau d'une opération et plus particulièrement lors du transitoire du mode opératoire (MOt) où les relations d'influence entre les variables sont faiblement connues ou non connues, ii) au sein d'une phase où les relations d'influence sont connues dans un intervalle de temps appartenant à l'horizon du mode opératoire. Concernant la complexité des relations des variables mises en jeu, il n'est pas toujours facile et forcément nécessaire une modélisation précise de la dynamique du procédé. Dans ce cas, les approches qualitatives permettent une représentation avec un degré d'abstraction plus en adéquation avec le niveau haut de surveillance considéré. Pour cela, nous proposons une abstraction des dynamiques continues basée sur un raisonnement temporel et événementiel compatibles avec les niveaux de la hiérarchie de surveillance. Cette abstraction est basée sur un partitionnement temporel flou de la dynamique des variables importantes définissant ainsi un ensemble d'états qualitatifs. Des mécanismes de vérification et de rétablissement de cohérence temporelle entre les variables sont proposés de façon à décrire les relations dynamiques locales existantes. Pour son pouvoir de représentation et pour rester cohérent avec une approche hiérarchique basée réseau de Petri, les Réseaux de Petri Temporels Flous ont été choisisThe supervision and monitoring systems have a major role to the security of an industrial plant and the availability of its equipments. Forewarn the operator earliest about the deviations of the process nominal behaviour is fundamental to carry out preventive and corrective actions. Some kind of industrial plants like the chemical process and batch systems set significant complexities to the monitoring and supervision systems because of their hybrid nature (discrete and continuous interactions), the number of active variables and the complexity of theirs behaviour relations. This complexity becomes more pronounced in systems characterized by numerous operating mode changes leading to a numerous transitory phases. The monitoring of these transitory phases is a delicate issue. The large amount of variables to be taken into account leads to a difficult reasoning and interpretation of the process behaviour. In case of fault, the diagnosis becomes then a complex task. The marginal deviations of process behaviour may indicate a dysfunction that degenerates slowly or be caused by operator misbehaviour or piloting system fault. To cope with this complexity we propose a hierarchical monitoring and control system completed by a procedural decomposition proposed by the ISA88 norm, defining from the upper level the recipes, procedures, operations, phases and tasks. Our monitoring and diagnosis approach is located at two high levels of this procedural hierarchy: i) at the operation level, particularly on the transition period of operating modes where the influence relations between the variables are weekly or not known, ii) at the phase level where the influence relations are known in a period of time belonging the transition operating mode horizon. .
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M'halla, Anis. "Contribution à la gestion des perturbations dans les systèmes manufacturiers à contraintes de temps." Thesis, Ecole centrale de Lille, 2010. http://www.theses.fr/2010ECLI0008/document.
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Les travaux proposés dans cette thèse s’intéressent à la commande et la surveillance d’une classe particulière de systèmes de production : les systèmes manufacturiers à contraintes de temps de séjour. Nous supposons dans l'étude que les ressources ont déjà été affectées et que l'ordre des opérations est déjà fixé par le module de planification/ordonnancement. Les hypothèses de fonctionnement répétitif avec et sans postes d'assemblage sont adoptées. De manière assez classique pour ce type de problématique, le formalisme utilisé est celui des Réseaux de Petri P-temporels pour l'étude des instants de débuts et de fins des opérations.Une étude de la robustesse des ateliers manufacturiers à contraintes de temps a été développée. La robustesse est abordée avec et sans modification de la commande relative à la robustesse active et à la robustesse passive respectivement, face aux perturbations temporelles. Un algorithme de calcul d'une borne supérieure de la robustesse passive est présenté. De plus, trois stratégies de commande robuste face aux perturbations temporelles ont été développées.Par ailleurs, l’incertitude dans les systèmes de production manufacturière à été étudié. Notre contribution dans ce cadre porte sur l’intégration des résultats concernant la robustesse dans la génération de symptômes et la classification des comptes rendus associés aux différentes opérations en utilisant la logique floue.Partant d’un système commandé, nous avons présenté en détail une démarche à suivre pour la mise en œuvre d’un modèle de surveillance en se basant sur les chroniques et les arbres de défaillance flous. Cette démarche est appliquée à un atelier de production laitièreThe works proposed in this thesis are interested in controlling and monitoring of a particular class of production system : manufacturing job-shops with time constraints. We suppose in the study that the resources are allocated and the operations order is fixed by the module of planning/scheduling. The assumptions of repetitive functioning mode with and without assembling tasks are adopted. For this type of problems, the formalism of P-time Petri nets is used in order to study the operations time constraints.A study of the robustness of the manufacturing workshop to time constraints, has been developed. The robustness is approached with and without control reaction qualified as active robustness and passive robustness respectively, towards time disturbances. A computing algorithm of the upper bound of the passive robustness is presented. In addition, three robust control strategies facing time disturbances were developed.Furthermore, uncertainty in manufacturing systems has been studied. Our contribution in this context is by integration of the analytical knowledge of the robustness in the filtering mechanism of sensors signals that are associated to operations, by using fuzzy logic.Starting from a controlled system, we have presented in detail, a method to be followed for the implementation of a monitoring model based on the chronicles and fuzzy fault tree analysis. This approach is applied to a milk production unit
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Ould-Kaddour, Nacéra. "Un outil pour le prototypage des systemes temps reel : le communicateur et son implementation." Toulouse 3, 1988. http://www.theses.fr/1988TOU30095.
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Les methodes de specification de la commande temps reel sont d'abord exposees. Les differents concepts, formalismes et modeles de communication et synchronisation sont discutes. Une approche basee reseaux de petri est proposee pour la specification entre taches. Une methodologie pour le prototypage des systemes temps reel est proposee, deux contributions etant developpees
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Nolibé, Gilles. "Developpement d'une methodologie de determination d'operateurs de calcul specifiques dans des problemes d'identification et d'estimation en temps reel." Toulon, 1988. http://www.theses.fr/1988TOUL0001.
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Elaboration d'une description algebrique des flux de donnees representatifs du traitement algorithmique de signal. Pour cela, une formulation de ces flux qui tient compte de l'ordonnancement des processus afin de determiner le parallelisme interne des algorithmes a implanter. Les resultats theoriques obtenus ont ete appliques a des problemes de traitement de signal
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Liu, Baisi. "Une approche efficace pour l’étude de la diagnosticabilité et le diagnostic des SED modélisés par Réseaux de Petri labellisés : contextes atemporel et temporel." Thesis, Ecole centrale de Lille, 2014. http://www.theses.fr/2014ECLI0007/document.
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Cette thèse s'intéresse à l'étude des problèmes de diagnostic des fautes sur les systèmes à événements discrets en utilisant les modèles réseau de Petri. Des techniques d'exploration incrémentale et à-la-volée sont développées pour combattre le problème de l'explosion de l'état lors de l'analyse de la diagnosticabilité. Dans le contexte atemporel, la diagnosticabilité de modèles RdP-L est abordée par l'analyse d'une série de problèmes K-diagnosticabilité. L'analyse de la diagnosticabilité est effectuée sur la base de deux modèles nommés respectivement FM-graph et FM-set tree qui sont développés à-la-volée. Un diagnostiqueur peut être dérivé à partir du FM-set tree pour le diagnostic en ligne. Dans le contexte temporel, les techniques de fractionnement des intervalles de temps sont élaborées pour développer représentation de l'espace d'état des RdP-LT pour laquelle des techniques d'analyse de la diagnosticabilité peuvent être utilisées. Sur cette base, les conditions nécessaires et suffisantes pour la diagnosticabilité de RdP-LT ont été déterminées. En pratique, l'analyse de la diagnosticabilité est effectuée sur la base de la construction à-la-volée d'une structure nommée ASG et qui contient des informations relatives à l'occurrence de fautes. D'une manière générale, l'analyse effectuée sur la base des techniques à-la-volée et incrémentale permet de construire et explorer seulement une partie de l'espace d'état, même lorsque le système est diagnosticable. Les résultats des simulations effectuées sur certains benchmarks montrent l'efficacité de ces techniques en termes de temps et de mémoire par rapport aux approches traditionnelles basées sur l'énumération des étatsThis PhD thesis deals with fault diagnosis of discrete event systems using Petri net models. Some on-the-fly and incremental techniques are developed to reduce the state explosion problem while analyzing diagnosability. In the untimed context, an algebraic representation for labeled Petri nets (LPNs) is developed for featuring system behavior. The diagnosability of LPN models is tackled by analyzing a series of K-diagnosability problems. Two models called respectively FM-graph and FM-set tree are developed and built on the fly to record the necessary information for diagnosability analysis. Finally, a diagnoser is derived from the FM-set tree for online diagnosis. In the timed context, time interval splitting techniques are developed in order to make it possible to generate a state representation of labeled time Petri net (LTPN) models, for which techniques from the untimed context can be used to analyze diagnosability. Based on this, necessary and sufficient conditions for the diagnosability of LTPN models are determined. Moreover, we provide the solution for the minimum delay ∆ that ensures diagnosability. From a practical point of view, diagnosability analysis is performed on the basis of on-the-fly building of a structure that we call ASG and which holds fault information about the LTPN states. Generally, using on-the-fly analysis and incremental technique makes it possible to build and investigate only a part of the state space, even in the case when the system is diagnosable. Simulation results obtained on some chosen benchmarks show the efficiency in terms of time and memory compared with the traditional approaches using state enumeration
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Grunwald, Stefanie. "Identifizierung und Charakterisierung von Muskeldystrophie Duchenne modifizierenden Genen und Stoffwechselwegen." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2010. http://dx.doi.org/10.18452/16108.
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Hintergrund und Zielsetzung: DMD ist die häufigste Form der Muskeldystrophie im Kindesalter und bis heute unheilbar. Sie wird durch das Fehlen des Proteins Dystrophin verursacht, welches verschiedene Signaltransduktionswege beeinflusst. Das Anliegen der Arbeit ist die Untersuchung und Modulation von Signaltransduktionswegen, die als alternative Therapiestrategie den Verlust von Dystrophin kompensieren könnten. Experimentelle Strategie: Für die Charakterisierung von Dystrophin nachgeschalteten Prozessen wurden mRNA-Expressionsanalysen in Muskelgeweben von DMD-Patienten und einem DMD-Brüderpaar mit einem infrafamiliär unterschiedlichen Verlauf der DMD durchgeführt. Aus diesen Expressionsdaten wurde erstmalig ein Petri-Netz entwickelt, welches Dystrophin mit in diesem Zusammenhang bisher unbekannten Signaltransduktionswegen verknüpft. Das Petri-Netz wurde auf Netzwerkintegrität und –verhalten mittels Invarianten- (INA) und theoretischen Knockout- (Mauritius Maps) Analysen untersucht. Durch beide Methoden läßt sich der maßgebliche Teilsignalweg bestimmen. In diesem Signalweg wurden die Proteinaktivität und die Genexpression durch siRNA, Vektor-DNA und chemische Substanzen in humanen SkMCs moduliert. Anschließend wurden die Proliferation und die Vitalität der Zellen sowie auch die Expression auf mRNA- und Protein-Niveau untersucht. Ergebnisse: RAP2B und CSNK1A1 waren in dem DMD-Brüderpaar differentiell exprimiert und konnten erstmalig in einem neuen, komplexen Signalweg in Zusammenhang mit Dystrophin nachgeschalteten Prozessen dargestellt werden. Mittelpunkt dieses Signalweges ist die De- und Aktivierung des Transkriptionsfaktors NFATc. Seine Zielgene umfassen neben anderen den negativen Proliferationsfaktor p21, das Dystrophin homologe UTRN und den Differenzierungsfaktor MYF5. Folglich würde ein Anstieg von UTRN eine unerwünschte Reduktion der Proliferationsrate von Myoblasten implizieren. Letzteres konnte bereits nachgewiesen werden und stellte das Motiv für weitere Studien dar. Jedoch zeigten siRNA- und Vektor-DNA-Experimente, daß NFATc nicht der ausschlaggebende Faktor für diese Zielgene ist. Die Substanzen Deflazacort (DFZ) und Cyclosporin A (CsA) wurden dagegen beschrieben, die Aktivierung von NFATc zu beeinflussen. Die Ergebnisse zeigten, daß beide Substanzen die Proliferation von Myoblasten erhöhen können. Die gleichzeitige Applikation von DFZ und CsA führte zu einem Anstieg der UTRN-Expression. Schlußfolgerung: Die Modulation der Proliferation und UTRN-Expression ist unabhängig von einander möglich. Entsprechend der Grundidee der Arbeit zeichnet sich eine neue Therapiestrategie ab, welche Dystrophin nachgeschaltete Prozesse einbezieht.Background and aim: DMD is the most common muscular dystrophy in childhood and incurable to date. It is caused by the absence of dystrophin, what influences several signal transduction pathways. The thesis is interested in the investigation and modulation of signal transduction pathways that may compensate the lack of dystrophin as an alternative therapy strategy. Experimental strategy: To study Dystrophin downstream pathways the mRNA expression of DMD patients and two DMD siblings with an intra-familially different course of DMD were analysed in muscle tissue. On the basis of these expression data a Petri net was first developed implicating signal transduction pathways and Dystrophin downstream cascades. Invariant (INA) and theoretical knockout (Mauritius Maps) analyses were applied for studying network integrity and behaviour. Both methods provide information about the most relevant part of the network. In this part modulation of protein activity and of gene expression using siRNA, vector-DNA, and chemical substances were performed on human SkMCs. Subsequently, the cells were studied by proliferation and vitality tests as well as expression analyses at mRNA and protein level. Results: RAP2B and CSNK1A1 were differently expressed in two DMD siblings, and first are part of a signal transduction pathway implicating Dystrophin downstream processes. The central point of this pathway is the de- and activation of the transcription factor NFATc. Its target genes are, among others, the negative proliferation factor p21, the Dystrophin homologue UTRN, and the differentiation factor MYF5. Consequently, an increase in UTRN implicates an undesirably reduced myoblast proliferation rate. Latter was found in DMD patients and was target for further studies. But, siRNA and vector DNA experiments showed that NFATc is not the decisive factor for the target genes. Deflazacort and cyclosporin A are known to influence the activation of NFATc. The results first showed that both substances do induce myoblast proliferation. The use of deflazacort in combination with cyclosporin A resulted in an increase of UTRN expression. Conclusion: The modulation of proliferation and UTRN-expression independently of each other is possible. According to the basic idea of this study, a new therapeutic strategy becomes apparent, which considers Dystrophin downstream processes.
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Clavareau, Julien. "Modélisation des stratégies de remplacement de composant et de systèmes soumis à l'obsolescence technologique." Doctoral thesis, Universite Libre de Bruxelles, 2008. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210482.
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Ce travail s’inscrit dans le cadre d’étude de la sûreté de fonctionnement.La sûreté de fonctionnement est progressivement devenue partie intégrante de l’évaluation des performances des systèmes industriels. En effet, les pannes d’équipements, les pertes de production consécutives, et la maintenance des installations ont un impact économique majeur dans les entreprises. Il est donc essentiel pour un manager de pouvoir estimer de manière cohérente et réaliste les coûts de fonctionnement de l’entreprise, en tenant notamment compte des caractéristiques fiabilistes des équipements utilisés, ainsi que des coûts induits entre autres par le non-fonctionnement du système et la restauration des performances de ses composants après défaillance.
Le travail que nous avons réalisé dans le cadre de ce doctorat se concentre sur un aspect particulier de la sûreté de fonctionnement, à savoir les politiques de remplacement d’équipements basées sur la fiabilité des systèmes qu’ils constituent. La recherche menée part de l’observation suivante :si la littérature consacrée aux politiques de remplacement est abondante, elle repose généralement sur l’hypothèse implicite que les nouveaux équipements envisagés présentent les mêmes caractéristiques et performances que celles que possédaient initialement les composants objets du remplacement.
La réalité technologique est souvent bien différente de cette approche, quelle que soit la discipline industrielle envisagée. En effet, de nouveaux équipements sont régulièrement disponibles sur le marché ;ils assurent les mêmes fonctions que des composants plus anciens utilisés par une entreprise, mais présentent de meilleures performances, par exemple en termes de taux de défaillance, consommation d’énergie, " intelligence " (aptitude à transmettre des informations sur leur état de détérioration).
De plus, il peut devenir de plus en plus difficile de se procurer des composants de l’ancienne génération pour remplacer ceux qui ont été déclassés. Cette situation est généralement appelée obsolescence technologique.
Le but de ce travail est de prolonger et d’approfondir, dans le cadre de la sûreté de fonctionnement, les réflexions engagées par les différents articles présentés dans la section état de l’art afin de définir et de modéliser des stratégies de remplacements d’équipements soumis à obsolescence technologique. Il s’agira de proposer un modèle, faisant le lien entre les approches plus économiques et celles plus fiabilistes, permettant de définir et d’évaluer l’efficacité, au sens large, des différentes stratégies de remplacement des unités obsolètes. L’efficacité d’une stratégie peut se mesurer par rapport à plusieurs critères parfois contradictoires. Parmi ceux-ci citons, évidemment, le coût total moyen engendré par la stratégie de remplacement, seul critère considéré dans les articles cités au chapitre 2, mais aussi la façon dont ces coûts sont répartis au cours du temps tout au long de la stratégie, la variabilité de ces coûts autour de leur moyenne, le fait de remplir certaines conditions comme par exemple d’avoir remplacé toutes les unités d’une génération par des unités d’une autre génération avant une date donnée ou de respecter certaines contraintes sur les temps de remplacement.
Pour arriver à évaluer les différentes stratégies, la première étape sera de définir un modèle réaliste des performances des unités considérées, et en particulier de leur loi de probabilité de défaillance. Etant donné le lien direct entre la probabilité de défaillance d’un équipement et la politique de maintenance qui lui est appliquée, notamment la fréquence des maintenances préventives, leur effet, l’effet des réparations après défaillance ou les critères de remplacement de l’équipement, un modèle complet devra considérer la description mathématique des effets des interventions effectuées sur les équipements. On verra que la volonté de décrire correctement les effets des interventions nous a amené à proposer une extension des modèles d’âge effectif habituellement utilisés dans la littérature.
Une fois le modèle interne des unités défini, nous développerons le modèle de remplacement des équipements obsolètes proprement dit.
Nous appuyant sur la notion de stratégie K proposée dans de précédents travaux, nous verrons comment adapter cette stratégie K à un modèle pour lequel les temps d’intervention ne sont pas négligeables et le nombre d’équipes limité. Nous verrons aussi comment tenir compte dans le cadre de cette stratégie K d’une part des contraintes de gestion d’un budget demandant en général de répartir les coûts au cours du temps et d’autre part de la volonté de passer d’une génération d’unités à l’autre en un temps limité, ces deux conditions pouvant être contradictoires.
Un autre problème auquel on est confronté quand on parle de l’obsolescence technologique est le modèle d’obsolescence à adopter. La manière dont on va gérer le risque d’obsolescence dépendra fortement de la manière dont on pense que les technologies vont évoluer et en particulier du rythme de cette évolution. Selon que l’on considère que le temps probable d’apparition d’une nouvelle génération est inférieur au temps de vie des composants ou supérieur à son temps de vie les solutions envisagées vont être différentes. Lors de deux applications numériques spécifiques.
Nous verrons au chapitre 12 comment envisager le problème lorsque l’intervalle de temps entre les différentes générations successives est largement inférieur à la durée de vie des équipements et au chapitre 13 comment traiter le problème lorsque le délai entre deux générations est de l’ordre de grandeur de la durée de vie des équipements considérés.
Le texte est structuré de la manière suivante :Après une première partie permettant de situer le contexte dans lequel s’inscrit ce travail, la deuxième partie décrit le modèle interne des unités tel que nous l’avons utilisé dans les différentes applications. La troisième partie reprend la description des stratégies de remplacement et des différentes applications traitées. La dernière partie permet de conclure par quelques commentaires sur les résultats obtenus et de discuter des perspectives de recherche dans le domaine.
Doctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished
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Gruer, Juan Pablo. "Eléments de synchronisation pour un langage temps-réel de commande de procédés." Mulhouse, 1989. http://www.theses.fr/1989MULH0105.
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Champagnat, Ronan. "Supervision des systèmes discontinus : définition d'un modèle hybride et pilotage en temps-réel." Toulouse 3, 1998. http://www.theses.fr/1998TOU30185.
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Cette thèse traite de la supervision des systèmes discontinus. Ce sont des systèmes qui transforment une matière première de type continu par l'intermédiaire d'équipements continus ou discontinus travaillant par lots. Après avoir rappelé le cas discret, nous présentons les particularités des systèmes discontinus. Cette étude nous permet de bien spécifier les besoins pour la modélisation et d'étudier les extensions des réseaux de Pétri pouvant représenter des systèmes hybrides. Ensuite, nous définissons formellement un modèle hybride, basé sur la combinaison d'un réseau de Pétri prédicats-transitions et de systèmes d'équations différentielles algébriques : les réseaux prédicats-transitions-différentiels. Les interactions entre les deux outils mathématiques sont formellement définies par l'introduction de fonctions de sensibilisation (tests sur les variables continues) et de jonction (calculs des valeurs initiales des variables continues). Afin de faciliter l'obtention d'un modèle dans le cadre des systèmes de grande taille, nous définissons formellement la fusion statique et la fusion dynamique de transitions dans le cadre des réseaux ordinaires et prédicats-transitions-différentiels. Puis nous donnons un ensemble de définitions permettant de garantir qu'un modèle est calculable s'il est composé de sous-modèles calculables. Il est alors possible d'avoir une approche modulaire pour l'obtention d'un modèle. Cette étude se termine par la présentation d'un algorithme de simulation des réseaux prédicats-transitions-différentiels. Dans la dernière partie, nous traitons la problématique de la supervision des systèmes discontinus. Dans un premier temps nous comparons les graphes potentiels et les réseaux de Pétri, ce qui nous permet de mettre en évidence un ensemble de contraintes venant du niveau ordonnancement et devant être pris en compte pour le pilotage en temps-réel du système. Puis dans un second temps nous proposons une approche pour le pilotage en temps-réel
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Sampietro, Samuele. "Timed Failure Logic Analysis in a Model-Driven Engineering approach." Doctoral thesis, 2021. http://hdl.handle.net/2158/1238685.
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A complex System of Systems, integrating several hardware and software components in the holistic perspective of providing an emergent behaviour and operating within business-critical contexts, aims at affording contrasting
requirements of reliability and complexity in delivered functions and quality of services by supporting system evolution and adaptation over time.
This dissertation contributes to the area of Model-Driven Engineering (MDE), proposing a model-driven approach supporting timed failure logic analysis of complex Cyber-Physical Systems (CPS) in business-critical scenarios.
The research defines a meta-model joining structural information about system architectures with their failure logic, decoupling representations of communication interfaces from those of failure propagation.
The meta-model also supports runtime evolution (which can be very fast in the case of complex CPS) of concrete systems by enabling the configuration of product lines, capable of representing multiple variation points of a component, supporting continuous adaptation of offered products and services to business or customer needs.
The meta-model enables a round-trip engineering process through the definition of a set of transformation rules, supporting the automated and correct-by-construction initialisation of meta-model instances starting from SysML Block Definition Diagrams for system specification and stochastic Fault Trees for timed failure logic, thus activating co-evolution mechanisms propagating external manual modifications, applied on meta-model instances, directly to the adopted structural and reliability artefacts. At the same time, a set of transformation rules has been defined so as to enable the automated generation of Stochastic Time Petri Nets (STPN) from meta-model instances, thus supporting quantitative evaluation of the imed failure logic.
The MDE approach is demonstrated on the case study of a CPS operating in a Smart City environment, evaluating at design time different configurations of the system with respect to the reliability of its cyber-side.
The research also addresses the design and the prototypical implementation of a tool offered both as-a-service and as a Java API.
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Li, Wen-Li, and 李文禮. "Analytical Method in Stochastic Timed Petri Nets." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/59459331695620216810.
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碩士淡江大學
資訊工程學系
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Petri Nets is a tool to describe and analyse systematic behavior.Especially after time is led into Petri Nets,such as Stochastic timed petri nets,the complicated behavior including concurrency,synchronization and nondeterminism of Concurrent / Distributed Systems can develop the modeling and evaluating system than ever.We can make structural property analysis from underlying Petri Net,and find out invariants being the basis of verifying behavior properties including safety and liveness.In addition,the analytical solution of relative continuous-time Markov Chain applying for Stochastic Timed Petri Nets can make performance evalution more efficiently for that system you describe. In this thesis ,by means of Reader and Writers problem,we lead systems of linear equations relative to analytical solution .On finding answer of the analytical solution,we adopt traditional Guass-Jorden elimination,and it is better for us to adopt Guass-Siedel and Jacobi methods for sparse matrix.On finding invariants,we adopt J.Martinez*s sequencial algorithm to get minimal support invariants,and we bring up the parallel algorithms under parallel computer systems.
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"Performance evaluation of stochastic timed decision-free Petri nets." Laboratory for Information and Decision Systems, Massachusetts Institute of Technology, 1985. http://hdl.handle.net/1721.1/1163.
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"Calculating time-related performance measures of a distributed tactical decisionmaking organization using stochastic timed petri nets." Massachusetts Institute of Technology, Laboratory for Information and Decision Systems, 1985. http://hdl.handle.net/1721.1/2908.
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Chen, Ching-Shyang, and 陳清祥. "Constructing Web Page Structure Model By Stochastic Timed Petri Nets." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/97006702915399248820.
Full textAbstract:
碩士淡江大學
資訊工程學系碩士班
93
The research on web usage mining provides the applications, such as behavior scheme analysis and web structure adjustment by analyzing the Web Usage Log and related data. This paper describes how to parse the static structure of a web, establish the Stochastic Timed Petri Nets model and apply its accessible-behavior feature to assist the web usage mining procedures like User Identification, Session Identification, Usage Pattern Discovery, etc.
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Sun, Chu-Hao, and 孫初豪. "Online Web Recommendation System by Using Stochastic Timed Petri Nets." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/84344430111548474760.
Full textAbstract:
博士淡江大學
資訊工程學系博士班
99
Web recommendation systems are typical applications of Web usage mining. The Web recommendation system is structured according to an online and an off-line component. The off-line component is aimed at building the knowledge base by analyzing past usage profiles that is then used in the online component. The general Web recommendation system mainly uses offline data preprocessing and the mining process is not time-limited. However, this approach is not suitable in real-time dynamic environments. Therefore, we need high-performance online Web usage mining techniques to provide solutions to these problems. In this paper, we propose an online Web recommendation system using STPN. The Web recommendation process consists of the data preparation phase, pattern discovery phase, and recommendation phase. In data preparation phase, we use STPN to model the Web structure, and also apply the Web metrics of Web graph properties to analyze the Web structure in improving the Web access. We simultaneously employ the Web structure analysis information in the incidence matrix and the reachability properties, obtained from the STPN model, to help proceed with pageview identification and path completion at the data preprocessing. In pattern discovery phase, the navigational graph and reachability graph are employed to model the usage profiles. We use the data stream mining technique to incrementally maintain the navigational graph over a sliding-window. The STPN’s reachability behavior characteristic and incidence matrix are applied to construct the reachability graph. In recommendation phase, we use the transition probability and steady-state probability in Markov model to predict the user’s navigational behavior. The navigational graph and reachability graph are used by the Web recommendation engine to generate the online dynamic Web recommendation. We combine the features of both the agent-based architecture and event-driven asynchronous notification architecture to achieve the online data preparation, pattern discovery, and recommendation.
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JHANG, HONG-JIA, and 張洪嘉. "Combination of Petri Net information flow, Timed Petri Net, Stochastic Petri Net and Petri Net Modeling of Buffers for innovative R&D process establishment and production flow analysis (PFA) of LED track light, as well as the related knowledgebase establishment." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/rkvm44.
Full textAbstract:
碩士國立臺灣科技大學
機械工程系
106
The paper applies Petri Net information flow, and combines Timed Petri Net theory, Stochastic Petri Net theory, Petri Net Modeling of Buffers and Petri Net dataflow calculation and integration information transmission concept, calculation data and production of time parameters, innovative development process of design and manufacture of LED track light for estimation of assembling time, and manufacturing process model. The paper designs the modeling of buffers in the production process, attempting to prevent blockade of raw materials and workpieces, and make the entire production process smoother and closer to the real situation. Besides, the paper also adds to the production process with the functions of manufacturing scheduling and computer-aided manufacturing process planning in order to make the manufacturing schedule planned more smoothly, more completely. Faster planning of manufacturing process can reduce the waste of time. And in the production process, there might be a situation that there is equipment needed to be repaired, and the maintenance staff may need a period of time to carry out maintenance of equipment. Therefore, the time spent on waiting for completion of equipment maintenance has to be added, letting users to understand more thoroughly the relationship between the overall design and the information of manufacturing flow. The paper also applies Petri Net theory and Petri Net dataflow calculation to establish a process flow model with calculation data to be applied to the modified TOPSIS method of the combined modified DANP of LED track light, so as to select a prioritized product function improvement program. The paper also enters and expands the theories relating to Petri Net information flow, the related knowledge required for planning the design and manufacturing processes, the related theoretical design and manufacturing knowledge, the modified TOPSIS of the combined modified DANP, and the related knowledge of patents, to the private cloud of theoretical knowledge relating to innovative development process, and to the knowledgebase of LED track light patents. In this way, the related LED track light knowledge can be increased, letting users learn the knowledge more easily, and allowing them to apply the knowledge to the innovative development process framework models.
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Weng, Chih-Hao, and 翁志豪. "Simulate the SCOR Process with Time Based Petri Net." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/17492453617647461543.
Full textAbstract:
碩士國立中央大學
工業管理研究所
92
Abstract In this paper, we introduce the concept of supply chain and supply chain management. When we want to discuss the issue of the supply chain, the SCOR Model must consider first, so we introduce what is SCOR Model. We know there are several tools to describe the process but fewer can monitor the process with spending time. The Petri Net is the tool to describe the system and we can present the states of the system by its token. But the base Petri Net always focuses on the single case rather than the multiple cases. For the issue, we create some elements and make the definitions of these elements, and then we also define our firing rules of my Petri Net and the relationships between the markings in the mathematical way. By using the elements that we created, we can simulate the process about the multiple cases and we can use the Petri Net to know the time of the process and calculate the total time that the job spent. In the research, we will make a correct proof and we will distribute the three parts (Source, Make, Deliver) of MTO (Make-TO-Order) of the SCOR Model. After understanding all the definitions of the elements of the MTO process, we will translate the MTO process into Petri net and follow the Petri net rule we created before and we will show how the marking and time change in several states.
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"Petri Net Modeling of Outpatient Waiting Time for MRI Examination." Thesis, 2013. http://hdl.handle.net/10388/ETD-2013-11-1304.
Full textAbstract:
In Canada, access to magnetic resonance imaging (MRI) examination is limited with an outcome of long patient waiting time. It is reported that the current median waiting time for MRI examination in Saskatoon is almost double the target for waiting time, which may aggravate the disease.
This research is towards reducing the waiting time of patients for MRI examination in Canada by applying an improved management. As a first step of this effort, a comprehensive model of MRI booking and serving system is needed. The city of Saskatoon was taken as an example and the MRI booking and serving system in the city was studied. The common tools (queuing theory, system dynamics (SD) and discrete event dynamics simulation (DES)) were compared and it is found that DES is more suitable, in particular Petri nets (PNs), deemed to be the best choice for the purpose of this thesis.
The model in this research was constructed on the basis of Hierarchical Coloured Petri nets (HCPNs), a combination of two extended PNs: Coloured PNs (CPNs) and Hierarchical PNs (HPNs). The model is able to simulate and predict patients' waiting times. Given that the structure of the model developed by HCPNs is still too complex, two extensions to CPNs, Ordered CPNs (OCPNs) and Prioritized HCPNs (PHCPNs), were proposed in this study to reduce the complexity of the model. Validation of the model was performed using the data of Saskatoon Health Region - Royal University Hospital. The results have shown that the proposed model can effectively describe the real system.
The model has potential applications in decision-making for the selection of an optimal booking strategy to shorten waiting time and in the prediction of possible waiting time of the system in the future, which may assist MRI administrators in the management of medical resources and may greatly improve the quality of MRI service.
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Shen, Zong-Yi, and 沈宗逸. "Combination of Petri Net information flow, Timed Petri Net and Stochastic Petri Net for innovative R&D process establishment and production flow analysis (PFA) of LED stage light, as well as the related knowledgebase establishment." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/75890556136001591453.
Full textAbstract:
碩士國立臺灣科技大學
機械工程系
105
The paper applies the innovative R&D process design and manufacturing process model of LED stage light, with prediction of production and assembling time that combines Petri Net information flow, Timed Petri Net theory, Stochastic Petri Net and Petri Net dataflow calculated and integrated information transmission concept, calculation data and time parameters. The paper adds the concept of “probability” to production process. Preconceiving the unexpected events that will possibly happen would make the whole production process closer to the real situation. The paper also adds the function of manufacturing lead time process planning to assembling process, avoiding unnecessary waste of cost and time to subsequent manufacturing process. Meanwhile, users can also understand more about the relationship between overall design and manufacturing process framework. The paper applies a process model, which is established by Timed Petri Net theory, Petri Net theory and Petri Net dataflow calculation, and possesses calculation data, time parameters, and calculation of design and assembling lead time, to a product function-based modified Decision-making Trial and Evaluation Laboratory (modified DEMATEL) of LED stage light. Modified DANP method, which combines product functions with the modified Analysis Network Process (modified ANP), is employed to perform selection of a prioritized improvement plan of product function. The paper also uses Petri Net information flow-related theory, the related knowledge required for design and manufacturing process planning, and the modified DANP method with product function, being design and manufacturing-related theoretical knowledge and the related patent knowledge. The above knowledge is entered and expanded to the private cloud of theoretical knowledge relating to innovative R&D process and knowledgebase LED stage light patents. In this way, stage light-related knowledge can be increased for users to learn more easily. The paper also adds the knowledge of material requirement planning, master production scheduling, inventory control and process planning, to the private cloud of theories about innovative R&D process. The paper also adds the Japanese patents to the public cloud of patents, and adds scheduling software to the private cloud of remote commercial software. As a result, they can be applied to innovative R&D process framework model; and the manufacturing and production process framework and mutual dependence relationship can be more complete.
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Cain and 蔡祁名. "Verifying Time Properties by Transforming Timing Diagram to Object-Oriented Time Petri Net." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/85513332010482606839.
Full textAbstract:
碩士東海大學
資訊工程與科學系
93
In system software development, time is a very important factor to the quality of the systems. Especailly there are more and more real time systems and embedded systems around people. Therefore, in UML 2.0 standard, OMG developed a new diagram called timing diagram which is used to described timing properties and interaction between objects. However, UML is a modeling language, it doesn't provide the technique to analyze and verify. For this reason, developers use timing diagram to describe the time properties but hard to know if there has some mistakes in timing diagram. The techniques of Petri nets are researched for years, and there are various analysis techniques to different domain. Some scholars’ research is to analyze the UML model by Petri net's analyzing properties. The focus of this thesis is on timing diagram. For this reason, we propose a mechanism to transform timing diagram to object-oriented time Petri net, it includes the specification of the timing diagram, the specification of the object-oriented time Petri net, and the transformation rules. After transforming, we utilize the analyzing abilities of Petri net to verify the timing properties. The example of this thesis is use the reachability analysis of Petri net to verify the correctness of the requirement.
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Hsi-ChuanWang and 王曦涓. "Using Petri Net to Estimate Job Execution Time in MapReduce Model." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/28576277544335563389.
Full textAbstract:
碩士國立成功大學
資訊工程學系碩博士班
101
Handling the vast amounts of data being generated currently requires large-scale data-processing techniques and has led to the recent growth of cloud computing. MapReduce is a key technique among several new concepts in cloud computing. After understanding how to develop parallel processing, programmers can use the MapReduce framework rapidly to complete parallel processing programs and exploit the high performance of computer clusters. One of the MapReduce implementations used most widely is Hadoop, which is the test platform used in this thesis. However, when running a MapReduce job, programmers cannot obtain information about how the performance of their application will be in their own test environment. Moreover, because several parameters affect the performance of Hadoop, programmers must spend a substantial amount of time identifying the most suitable parameters or studying their details in MapReduce. In this thesis, execution details in MapReduce are examined in depth and described using Stochastic Petri Net (SPN) to then develop the SPN-MapReduce (SPN-MR) model. To analyze the performance of SPN-MR, mean delay time formulas are defined for each timed transition. SPN-MR is the first proposed which can estimate the execution time of MapReduce jobs with a known input data size in hundreds of milliseconds and reduce the time spent by programmers in tuning performance. The experimental results of SPN-MR are compared with two benchmarks of actual tests and the average error range is found to be within 5% under 10GB input data. Therefore, SPN-MR can enable MapReduce programmers to evaluate performance effectively.
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Yi-ChenShen and 沈奕辰. "Enhancing Diagnostic Performance in Batch Processes with Petri-Net Representation of Time." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/59163229026047654416.
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Jhong-Yi, Guo, and 郭仲毅. "A New Reduction Methord for Time Petri Net Systems Using Matching Theory." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/65401471617064647440.
Full textAbstract:
碩士國立臺北大學
通訊工程研究所
96
In this thesis, we present an efficient method to solve the state explosion problem in Petri nets by using matching theory. It is really hard to analyze a Petri net while there are too many states in a Petri net. In order to solve such a problem, we address a way to label the weight value on a transition according the relationship between places and transitions. Then we select the transition which is related to the maximum one after sorting weights. The transition we select is the most important and connective one for the whole Petri nets at the moment. After selecting the transition for several times, the last one denotes the least connection in the whole Petri nets, and we could reduce the Petri net model from this transition. Finally, main results are presented and supported by some experiments.
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Chi, Chen-Chung, and 季振忠. "The Use of Stochastic Timed Petri Nets To Help Data Preprocessing Procedure In Web Mining." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/83496522751360745361.
Full textAbstract:
碩士淡江大學
資訊工程學系碩士班
93
Data preprocessing is an important procedure in web usage mining. In this paper, we will discuss some major questions in data preprocessing, and then provide some methods to help to solve these problems. In a web usage mining process, if we do not complete the web structure analysis at first, then we cannot truly complete data preprocessing, as well seriously affects the accuracy in pattern discovery. Therefore, in the present paper, we utilize Stochastic Timed Petri Nets (STPN) and its reachability behavior characteristic, as well as the constructed web structure which produces after the web structure analysis, to help web content scope recognization and path completion procedure.
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Kao, Hsiu-Che, and 高脩哲. "Prototyping for real-time system based on enhanced Petri net and production system." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/99419413275227505049.
Full textAbstract:
碩士國立臺灣大學
資訊工程研究所
81
Real-time computing systems have appeared more widely in recent times. Based upon clear and manageable specification of timing constraints structure in real-time systems development, the quality of the specification of timing constraints can be examined during software development. In this paper, we propose an Enhanced Time Petri Net (ETPN) to model the timing constraints in both hard and soft real-time system. The model ETPN can describe the real systems more possibly and is associated a set of systematic analysis methods to find the inconsistency among timing constraints in the model. Our prototyping strategy is to use ETPN as a modeling tool and the text description of ETPN as the prototype. We choose AI production system as our environment which is as an simulation tool that can help us to examine the behavior of specification through the assistance of executing the prototype. Using the automatic rule translator to transform the prototype description to a set of rules and data that are executed through the inference engine is the main method to analyze the specification. In this paper, we propose a systematic specification and analysis method which combines with the concept of prototyping based on a production system, RTworks, to deal with the special properties of time-critical application. In this work, we use two demonstrating examples : rail-road crossing and telephone system that will show the usage and the effectiveness of the prototyping method.
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Jao, Yueh –. Feng, and 饒岳峰. "The Study of Three-Dimensional VR Description Tools Using Time-Object-Oriented Petri Net." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/62824318468728626359.
Full textAbstract:
碩士中國文化大學
資訊管理研究所
95
This research extends predecessor’s research on combining Object-Oriented High Level Petri Nets (OPNets) with time delay interval of Time Petri Nets to model two-dimensional virtual reality, and advances a method of modeling user roaming, change of user view angle, and object interaction activities in three-dimensional virtual reality.We modify and extend predecessor’s reachability tree, and then put forward a time reachability tree with the ability to detect the deadlock, unexpected end, loop, and a kind of peculiar loop in the system. This thesis not only proves this method, but also compresses the optimum processes with the reachability graph to detect the deadlock and the proposed peculiar loop in the system. OPNets are petri nets with object-oriented property, and have the general charac-teristics of Petri Nets. So, it is useful to describe parallel, concurrent, distributed systems and nondeterministic systems with dynamic behaviors. OPNets is a graphical expression tool, and offers a quality algebraic semantic that can be used for verifying the system’s behavior. Time delay interval is the structure of describing the firing time interval of the Time Petri Nets, and it also defines earliest and latest firing time of the Time Petri Nets. But the ready-made method of detecting the deadlock or other problems in the OPNets with time delay interval is not existing now. This thesis extends predecessor’s reachability tree to detect the deadlock, unexpected end, loop, and peculiar loop in the Time Object-Oriented Petri Nets.
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Lee, Yung-Yu, and 李永裕. "Parallel programming design、implementation and analysis – a case study on Analytical Solution for Stochastic Timed Petri Nets." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/53399104325094795572.
Full textAbstract:
碩士淡江大學
資訊工程學系
86
A parallel program can use these distributed computing resources efficiently, and a good parallelized program depends on the good designing and analyzing rocesses. In this thesis, we use Ian Foster''s designing method of parallel program and analyze through the four steps of decomposition, communication, agglomeration and mapping. We use a case study on analytical solution for Stochastic Timed Petri Nets which use three algorithms to solve the problems, they are, Gauss elimination method, Jacobi method and Gauss-siedel method. The computations often stop because of the page faults. Here we analysis the Embedded Markov Model matrices from two different ways: Depth Search First and Breadth Search First. Through the comparison, we find that breadth search first will be better for overcoming the insufficient computation resource problem. If the embedded Markov model matrix has been existed, we also provide a method for translating the original matrix into a simpler one. Under limited computation resource, this algorithm will execute concurrently and be able to process bigger matrices. In the second and third, we use breadth search first or those matrix has been translated, such that each task can acquire the data just from itself. And this will decrease the communication amount and message length, so as to ease the communication cost and increase the concurrency. After all of these, we also implement these parallel versions of the algorithms in practice. Here, we done these in Parallel Virtual Machine environment, where it is easy to change the amount of computational resources so as to know the difference of the parallelized algorithm in efficiency. After that, we can review the designing steps and adjust it.
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Lee, Ming Rong, and 李銘榮. "The Development of An Object-Oriented Petri Net Flexible Manufacturing Cell Real Time Scheduling System." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/09833484005789694676.
Full textAbstract:
碩士東海大學
工業工程學系
85
The performance of a flexible manufacturing cell (FMC) is highly dependent on the effectiveness of its scheduling system. This paper presents an approach which consists of two parts: (1) order release and resource allocation, and (2) operations scheduling. A constraint satisfaction technique (CST) is first employed to determine the appropriate order release time and allocated resource (e.g., fixture in each pallet) for each part in the order pool. Then, a colored timed object-oriented Petri net (CTOPN), which owns the characteristics of an object- oriented approach (e.g., the high degree of modularity, reusability, and maintenanability of the model), is presented to model the dynamic behavior of a FMC and to obtain the daily operations schedule for each resource (e.g., machining centers, washing machine, RGV, and loading/unloading equipments) by considering the characteristics of concurrent behavior, alternative routings, resource sharing and conflict in a FMC. Research of this CTOPN-based FMC scheduling system is sponsored by the Economic Affairs of Taiwan and has been successfully implemented in the FMC developed by the local industry in Taiwan (i.e., VICTOR Taichung Machinery Works Co., Ltd.).
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NIU, BING-XIAN, and 牛秉憲. "Real-time scheduling in FMS with multiple material handling systems using petri-net based techniques." Thesis, 1991. http://ndltd.ncl.edu.tw/handle/34609648370534960982.
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Huang, Bo-Wei, and 黃柏維. "A Timed Petri Net Approach for Job Shop Scheduling with Setup Time and Routing Flexibility." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/20782766865329297372.
Full textAbstract:
碩士國立雲林科技大學
工業工程與管理研究所碩士班
101
In order to reach the customization, multi-functional machines become more and more. It can execute the different operation by changing tools and modulating the process parameters. As the reason, it raises the routing flexibility in the manufacturing system, and the times about changing tools and modulating parameters call setup times. This paper proposes a method to job shop scheduling problems with anticipatory independent setup times and routing flexibility. First, timed petri nets are used for presenting the behavior of job shop scheduling problems. Then, a mathematical programming model is constructed based on the timed petri nets. An A* algorithm with dynamic weighting heuristic function developed by Bo Huang is modified to find optimal or sub-optimal scheduling solution. The proposed dynamic weighting heuristic function with newly adding minimum operation residual time is developed to solve the scheduling problem. Finally, an example of a job shop scheduling problem is given to verify the proposed algorithm, and the results show that the performance of the proposed algorithm is better than other A* algorithms. In addition, and the A* algorithms with adding the minimum operation residual time have better performances than those without adding the minimum operation residual time.
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chen, Yen-chen, and 陳彥臻. "A Coloured Timed Petri Net approach for shortest traveling time and deadlock avoidance of AGV systems." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/18402962001439920872.
Full textAbstract:
碩士國立雲林科技大學
工業工程與管理研究所碩士班
99
The automated guided vehicle (AGV) system is the most flexible material handling system. AGV system design must consider some management issues to avoid resource conflicts and deadlock situations from occuring, and to process material handling in the shortest time to complete the work. When AGV system deadlock occurs, the system may cause paralysis or blockage, and reduce the overall system productivity. In this research, based on the given layout and job requirements of a bidirectional AGV system, we investigated a deadlock-free system and the shortest travel time path. First, the AGV coloured timed petri net (ACTPN) model is established and is used to describe the dynamic behavior of AGVs to analyze the conditions of deadlock and establish the deadlock avoidance policies. Then, according to the deadlock avoidance policies and consider synchronous mode of operation, the Best-First search (BFS) rule is introduced to find the dispatching sequences for AGVs.
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Tsai, Chen-Ting, and 蔡承廷. "Application of Fuzzy-Time Petri Net to Resource Scheduling for Large-Scale Contingencies of Distribution Systems." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/30698616314920483123.
Full textAbstract:
碩士國立高雄應用科技大學
電機工程系碩士班
93
Significant damages caused by extreme weather conditions such as typhoon, flood, storm could result in multiple and widely-spread outages in distribution systems. The electric utilities will send repair crew to deal with the outages as soon as possible. Due to the limits of repair resources in a large-scale multiple contingencies, an effective resource management is especially crucial. In this thesis, fuzzy sets and fuzzy operations for the events and the resources are proposed to deal with uncertainties in the scheduling. A Fuzzy Time Petri Net(FTPN) model is proposed to be the inference system of the contingent resource scheduling system. The geographical information and the relational data base imbedded in the Outage Management System(OMS) are integrated with crew-and-vehicle resource data base to support the FTPN inference system. Load transfer is also considered for the out-of-service areas before and after the completion of the repairs. Sequence and the repairing time of the events, time to send and the listing of the crews and engineering-vehicles, and the time of completion of the events will be obtained in the scheduling system. To demonstrate the effectiveness of the proposed fuzzy rule-based expert system and FTPN models, a practical distribution system in Tainan region with detailed data in the OMS is selected for computer simulation. It is found that proposed methodology provides the capability of contingent management of the resources effectively.
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Biagi, Marco. "New methods for quantitative evaluation of Markov regenerative models." Doctoral thesis, 2019. http://hdl.handle.net/2158/1152945.
Full textAbstract:
The thesis describes the research that has been carried out in order to reduce the limitations of current analysis techniques for non-Markovian models, which
led to a three-fold contribution. The first contribution is a technique that allows to integrate different analysis techniques for the evaluation of kernels of a MRGP. Specifically, the state space of the underlying timed model is analyzed to identify epochs between regenerations and apply distinct methods for their analysis depending on the locally satisfied conditions. For epochs not amenable to existing methods, an adaptive approximation of kernel entries based on partial exploration of the state space is proposed, leveraging heuristics that permit to reduce the error on transient probabilities. This approach extends the class of models that can be analyzed, reduces errors committed by approximate analysis and allows one to automatize the selection of the analysis technique.
The second contribution is a technique for the computations of the equilibrium probability density functions (PDFs) for the continuous component of the state in MRGP. Equilibrium PDFs are derived as closed-form analytical expressions by applying the Key Renewal Theorem to stochastic state classes computed between regenerations. This techniques provides a basis to analyze system properties from the equilibrium such as survivability.
The last contribution, is an extension of the analysis of hierarchical semi-Markov processes with parallel regions, a technique that evaluates steady-state
probabilities of models with multiple concurrent non-Markovian timers in a compositional way without the need of full state space generation. Specifically, the technique has been extended by removing some of its limitations and increasing its modeling power. By applying the time advancement mechanism known from stochastic state classes, exits in parallel regions with different time origins can be taken into account. Furthermore, exits can be put on state borders such that the model evolution depends on the exited region and a concept for history states is also presented. This significantly increases modeling power, such that the gap between semi-Markov processes with restricted modeling power and non-Markovian models without modeling restrictions but also
with less efficient analysis is filled.
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Zhang, Jun-Feng, and 張浚峰. "Applying Colored Time Petri Net to map out the maintenance of shared-load (2,2,1) Spin Coater system." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/swkewt.
Full textAbstract:
碩士國立中央大學
機械工程研究所
94
The manufacture of the DVD disc contains some necessary processes, whish are disc molding, cooling, dye coating, drying, sputtering, edge cleaning, bonding, and UV-curing. The quality of products will be affected by every manufacturing process. Because of the defects in designing and the external facts of operation, the equipment or components can be damaged in some aspects, such as mechanical fatigue and abrasion . In the DVD disc manufacturing process, the equipment of dye coating called Spin Coater functions with rotation. Due to the unbalanced rotation, the bearing of Spin Coater will be fatigued. In this thesis, we have two discussions on shared-load (2,2,1) system of Spin Coater : (1) The load and the hazard rate of the Spin Coater. (2) Applying Colored Time Petri Net to simulate the failure of the Spin Coater, and to map out the period of maintenance.
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Huang, Chang-Sheng, and 黃長勝. "A Time Petri Net Approach Applied to the Modeling and Analysis of Golf heads Cast Manufacturing Systems." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/37241144766170392199.
Full textAbstract:
碩士國立高雄應用科技大學
工業工程與管理系碩士班
95
The golf club is fashionable sport apparatus that is used extensively, and the basic structure of a golf product includes the golf head, ferrule, golf shaft and the grip. The golf head, striking golf balls straight, is the most important part of a golf product, and its shape design, manufacturing methods and materials will influence the quality and cost of the golf product directly. At present, The golf head is mostly made of titanium, the manufacturing methods of golf heads mainly focus on precision casting. It goes several procedures that include metal pattern manufacturing, wax pattern injection, overhaul wax shells, wax tree assemble、slurry dip, dewaxing, casting, heat treatment, raw product modifying , polishing, art designing and packing. During the complicated productions, the relationship of every job flow might not be controlled correctly due to improper job flows, and might result in resource wasting, production cost increasing, production flows locking and business benefits decreasing because some working requirements and limited resources can’t be used efficiently. The research object of this study is based on the production flows of a golf products manufacturing factory in southern Taiwan. During the procedure of golf club production, the system is due to improper processing procedure, mistake of mutual resource or planning schedule that result in productive procedure holding up, producing non-smoothly and delaying phenomenon. It uses step oriented transition Petri Nets, timed Petri Nets and continuous Petri Nets making a way of hybrid Petri Nets to carry out briefly description and detection, discusses the continuity, cyclic time and efficiency of production operation. That can monitor the production via Petri Nets with the production time of wax shells work station & cast work station of casting plant, eliminates unnecessarily wasting time, increases production efficiency and decreases production cost, and finds out the relationship of every working activity by the character of Petri Nets drawings to discuss the system efficiency. The precise casting procedure of golf club can be improved by Petri Nets drawings analysis. The productive efficiency of every golf wax tree assemble can be increased by 14.8%, every productive efficiency of raw product of golf club can be improved by 15.78%. That shortens the procedural time and reduces the productive cost.