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Tesi sul tema "Petri nets"
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1
Bowden, Fred D. J. "The modelling and analysis of command and control decision processes using extended time petri nets". Title page, table of contents and abstract only, 2001. http://web4.library.adelaide.edu.au/theses/09PH/09phb784.pdf.
Testo completoAbstract (sommario):
Bibliography: leaves 177-191. This thesis uses a new type of extended time Petri net to model and analyse command and control decision processes. A comprehensive review of existing time Petri net structures is given. This concludes with the introduction of time Petri net structure that incorporates the most commonly used time structures. This extended time Petri net structure is then used in the definition of the basic modelling blocks required to model command and control decision processes. This basic modelling block forms the basis of the direct analysis techniques that are introduced in the thesis.
2
Jin, Wei. "Petri nets and their applications". Virtual Press, 1991. http://liblink.bsu.edu/uhtbin/catkey/774753.
Testo completoAbstract (sommario):
Petri nets are named in honor of Dr. Carl A. Petri for his famous Ph.D dissertation of general net theory in 1962. A substantial amount of work utilizing and modifying the Petri nets has been done since then, and they have turned out to be very useful in the study of asynchronous concurrent systems. The liveness and reachability problems are considered to be some of the major problems in Petri net theory.Since the structure of a Petri net can be regarded as sets of places and transitions form a graphical point of view, this thesis is concerned with utilizing the results of graph theory to investigate the liveness in terms of deadlock problems of a special subclass of Petri nets, free-choice Petri nets. As a subclass of Petri nets, the class of free-choice Petri nets possesse relatively strong analysis properties. This is especially true of complete free-choice Petri nets. We show in particular that any system which can be modeled by a general Petri net can also be modeled by a free-choice Petri net.Department of Computer Science
3
Dahlbom, Anders. "Petri nets for situation recognition". Doctoral thesis, Örebro universitet, Akademin för naturvetenskap och teknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-13089.
Testo completoAbstract (sommario):
Situation recognition is a process with the goal of identifying a priori defined situations in a flow of data and information. The purpose is to aid decision makers with focusing on relevant information by filtering out situations of interest. This is an increasingly important and non trivial problem to solve since the amount of information in various decision making situations constantly grow. Situation recognition thus addresses the information gap, i.e. the problem of finding the correct information at the correct time. Interesting situations may also evolve over time and they may consist of multiple participating objects and their actions. This makes the problem even more complex to solve. This thesis explores situation recognition and provides a conceptualization and a definition of the problem, which allow for situations of partial temporal definition to be described. The thesis then focuses on investigating how Petri nets can be used for recognising situations. Existing Petri net based approaches for recognition have some limitations when it comes to fulfilling requirements that can be put on solutions to the situation recognition problem. An extended Petri net based technique that addresses these limitations is therefore introduced. It is shown that this technique can be as efficient as a rule based techniques using the Rete algorithm with extensions for explicitly representing temporal constraints. Such techniques are known to be efficient; hence, the Petri net based technique is efficient too. The thesis also looks at the problem of learning Petri net situation templates using genetic algorithms. Results points towards complex dynamic genome representations as being more suited for learning complex concepts, since these allow for promising solutions to be found more quickly compared with classical bit string based representations. In conclusion, the extended Petri net based technique is argued to offer a viable approach for situation recognition since it: (1) can achieve good recognition performance, (2) is efficient with respect to time, (3) allows for manually constructed situation templates to be improved and (4) can be used with real world data to find real world situations.Anders Dahlbom is also affiliated to Skövde Artificial Intelligence Lab (SAIL), Information Fusion Research Program, Högskolan i Skövde
4
David, Nicolas. "Discrete Parameters in Petri Nets". Thesis, Nantes, 2017. http://www.theses.fr/2017NANT4108/document.
Testo completoAbstract (sommario):
Afin de permettre une modélisation plus souple des systèmes, nous proposons d’étendre les réseaux de Petri par des paramètres discrets représentant le poids des arcs ou le nombre de jetons présents dans les places. Dans ce modèle, tout problème de décision peut être décliné sous deux versions, une universelle, demandant si la propriété considérée est vraie quelles que soient les valeurs que prennent les paramètres et une existentielle, qui s’interroge sur l’existence d’une valeur pour les paramètres telle que la propriété soit satisfaite. Concernant la couverture, nous montrons que ces deux problèmes sont indécidables dans le cas général. Nous introduisons donc des sous classes syntaxiques basées sur la restriction des paramètres aux places, aux arcs en sortie ou aux arcs en entrée des transitions. Dans ces différents cas, nous montrons que la couverture existentielle et universelle sont décidables et EXPSPACE-complètes. Nous étudions alors le problème de la synthèse de paramètres qui s’intéresse à calculer l’ensemble des valeurs de paramètres telles que la propriété considérée soit vraie. Sur les sous classes introduites, concernant la couverture, nous montrons que les ensembles solutions à la synthèse ont des structures fermée supérieurement (cas des arcs de sortie) et fermée inférieurement (cas des arcs d’entrée). Nous prouvons alors que ces ensembles se calculent par un algorithme de la littérature, proposé par Valk et Jantzen, dont les conditions d’application se réduisent aux problèmes de décision étudiés précédemment. Enfin nous étudions les frontières de décision en nous intéressant aux versions paramétrées de l’accessibilité pour ces sous classesWith the aim of increasing the modelling capability of Petri nets, we suggest that models involve parameters to represent the weights of arcs, or the number of tokens in places. We consider the property of coverability of markings. Two general questions arise, the universal and the existential one: “Is there a parameter value for which the property is satisfied?” and “Does the property hold for all possible values of the parameters”. We show that these issues are undecidable in the general case. Therefore, we also define subclasses of parameterised nets, depending on whether the parameters are used on places, input or output arcs of transitions. For some classes, we prove that universal and existential coverability become decidable, making these classes more usable in practice. To complete this study, we prove that those problems are EXPSPACE-complete. We also address a problem of parameter synthesis, that is computing the set of values for the parameters such that a given marking is coverable in the instantiated net. Restricting parameters to only input weights (preT-PPNs) provides a downward-closed structure to the solution set. We therefore invoke a result for the representation of upward closed set from Valk and Jantzen. The condition to use this procedure is equivalent to decide the universal coverability. We also propose an adaptation of this reasoning to the case of parameters used only as output weights (postT-PPNs). In this case, the condition to use this procedure can be reduced to the decidability of the existential coverability. Finally, we broaden this study by establishing decision frontiers through the study of existential and universal reachability
5
BARROSO, GIOVANNI CORDEIRO. "A STUDY ON COLORED PETRI NETS AND A PROGRAM TO ANALYZE COLORED PETRI NETS: ANARCO". PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 1987. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=14192@1.
Testo completoAbstract (sommario):
A modelagem de sistemas que apresentam subsistemas idênticos, por intermédio de Redes de Petri, conduz à geração de grafos de grandes dimensões com diversos componentes indênticos.
As extensões às Redes de Petri que permitem diferenciar estes diversos subsistemas, por intermédio da distinção das fichas nelas contidas, receberam o nome de Redes de Petri Coloridas.
Neste trabalho, são apresentados algumas propostas existentes na literatura sobre Redes de Petri Coloridas, bem como é desenvolvido um programa de análise baseado em uma dessas propostas - a de kurt Jensen.
O programa analisa as propriedades de uma Rede de Petri Colorida, tais como limitação, vitalidade e capacidade de reinicialização, através do método de enumeração de marcações.The modeling of sistems which have identical sub-systems, by means of Petri nets, leads to the generation of large scale graphs with identical components. The extensions of Petri nets, which afford the possibility of distinguishing these sub-systems through the distinction of the tokens within the net, are called colored Petri nets. This work presents some colored Petri net proposals existent in literature and an analysis code based on one of these proposals - the Kurt Jensen one. This program analyses through the mark enumeration method, the colored Petri net properties, such as boundedness, liveness and reinicialization.
6
Masapati, Gulammahammad Hasanasaheb. "Performance prediction using timed Petri nets". Thesis, University of Ottawa (Canada), 1987. http://hdl.handle.net/10393/5155.
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7
Kyratzoglou, I. M. (Ioannis M. ). "Computer aided design for Petri Nets". Thesis, Massachusetts Institute of Technology, 1987. http://hdl.handle.net/1721.1/14669.
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Ghahremani, Azghandi Nargess. "Petri nets, probability and event structures". Thesis, University of Edinburgh, 2014. http://hdl.handle.net/1842/9936.
Testo completoAbstract (sommario):
Models of true concurrency have gained a lot of interest over the last decades as models of concurrent or distributed systems which avoid the well-known problem of state space explosion of the interleaving models. In this thesis, we study such models from two perspectives. Firstly, we study the relation between Petri nets and stable event structures. Petri nets can be considered as one of the most general and perhaps wide-spread models of true concurrency. Event structures on the other hand, are simpler models of true concurrency with explicit causality and conflict relations. Stable event structures expand the class of event structures by allowing events to be enabled in more than one way. While the relation between Petri nets and event structures is well understood, the relation between Petri nets and stable event structures has not been studied explicitly. We define a new and more compact unfoldings of safe Petri nets which is directly translatable to stable event structures. In addition, the notion of complete finite prefix is defined for compact unfoldings, making the existing model checking algorithms applicable to them. We present algorithms for constructing the compact unfoldings and their complete finite prefix. Secondly, we study probabilistic models of true concurrency. We extend the definition of probabilistic event structures as defined by Abbes and Benveniste to a newly defined class of stable event structures, namely, jump-free stable event structures arising from Petri nets (characterised and referred to as net-driven). This requires defining the fundamental concept of branching cells in probabilistic event structures, for jump-free net-driven stable event structures, and by proving the existence of an isomorphism among the branching cells of these systems, we show that the latter benefit from the related results of the former models. We then move on to defining a probabilistic logic over probabilistic event structures (PESL). To our best knowledge, this is the first probabilistic logic of true concurrency. We show examples of expressivity achieved by PESL, which in particular include properties related to synchronisation in the system. This is followed by the model checking algorithm for PESL for finite event structures. Finally, we present a logic over stable event structures (SEL) along with an account of its expressivity and its model checking algorithm for finite stable event structures.
9
Li, Yao Carleton University Dissertation Engineering Electrical. "Solution techniques for stochastic petri nets". Ottawa, 1992.
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10
MASCHERONI, MARCO. "Hypernets: a class of hierarchical petri nets". Doctoral thesis, Università degli Studi di Milano-Bicocca, 2011. http://hdl.handle.net/10281/19228.
Testo completoAbstract (sommario):
The interest of this thesis is on modeling systems of mobile agents, systems composed of several open and autonomous components which can interact and move inside one or more environments.
Several proposal for modeling mobility have been introduced. They can be roughly divided in two categories: Petri net based formalisms, and process algebra based formalisms.
In this thesis, Petri net formalisms will mostly be considered, with particular care to formalisms which use the nets-within-nets paradigm. In models compliant to this paradigm the tokens of a Petri net can be nets themselves. Since systems of mobile agents exhibit a nesting structure, it seems natural to use this paradigm.
In particular, the focus of this dissertation is on the hypernet model, whose main characteristic is that it has a limited state space, characteristic that make it suitable to be analyzed using well known Petri net techniques.
The thesis topics range from theoretical aspects of the model to more practical issues.
From a theoretical point of view an extension of the model is introduced. It is proved that this extension preserves all the good properties of the basic model. It is also studied how to apply the well known unfolding technique to this model.
From a practical point of view is is shown how the nets-within nets paradigm can be used to model systems based on the Grid infrastructure. Moreover, a tool which allow to draw and to analyze an hypernet is discussed.
11
Tanabe, Makoto. "Timed Petri Nets and Temporal Linear Logic". 京都大学 (Kyoto University), 1999. http://hdl.handle.net/2433/181934.
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12
Shaw, Oliver James. "Modelling bacterial regulatory networks with Petri nets". Thesis, University of Newcastle Upon Tyne, 2007. http://hdl.handle.net/10443/1963.
Testo completoAbstract (sommario):
To exploit the vast data obtained from high throughput molecular biology, a variety of modelling and analysis techniques must be fully utilised. In this thesis, Petri nets are investigated within the context of computational systems biology, with the specific focus of facilitating the creation and analysis of models of biological pathways. The analysis of qualitative models of genetic networks using safe Petri net techniques was investigated with particular reference to model checking. To exploit existing model repositories a mapping was presented for the automatic translation of models encoded in the Systems Biology Markup Language (SBML) into the Petri Net framework. The mapping is demonstrated via the conversion and invariant analysis of two published models of the glycolysis pathway. Dynamic stochastic simulations of biological systems suffer from two problems: computational cost; and lack of kinetic parameters. A new stochastic Petri net simulation tool, NASTY was developed which addresses the prohibitive real-time computational costs of simulations by using distributed job scheduling. In order to manage and maximise the usefulness of simulation results a new data standard, TSML was presented. The computational power of NASTY provided the basis for the development of a genetic algorithm for the automatic parameterisation of stochastic models. This parameter estimation technique was evaluated on a published model of the general stress response of E. coli. An attempt to enhance the parameter estimation process using sensitivity analysis was then investigated. To explore the scope and limits of applying the Petri net techniques presented, a realistic case study investigated how the Pho and aB regulons interact to mitigate phosphate stress in Bacillus subtilis. This study made use of a combination of qualitative and quantitative Petri net techniques and was able to confirm an existing experimental hypothesis.
13
Hall, Jon G. "An algebra of high level Petri nets". Thesis, University of Newcastle Upon Tyne, 1996. http://hdl.handle.net/10443/2166.
Testo completoAbstract (sommario):
Petri nets were introduced by C.A. Petri as a theoretical model of concurrency in which the causal relationship between actions, rather than just their temporal ordering, can be represented. As a theoretical model of concurrency, Petri nets have been widely successful. Moreover, Petri nets are popular with practitioners, providing practical tools for the designer and developer of real concurrent and distributed systems. However, it is from this second context that perhaps the most widely voiced criticism of Petri nets comes. It is that Petri nets lack any algebraic structure or modularity, and this results in large, unstructured models of real systems, which are consequently often intractable. Although this is not a criticism of Petri nets per se, but rather of the uses to which Petri nets are put, the criticism is well taken. We attempt to answer this criticism in this work. To do this we return to the view of Petri nets as a model of concurrency and consider how other models of concurrency counter this objection. The foremost examples are then the synchronisation trees of Milner, and the traces of Hoare, (against which such criticism is rarely, if ever, levelled). The difference between the models is clear, and is to be found in the richness of the algebraic characterisations which have been made for synchronisation trees in Milner's Calculus of Communicating Systems (CCS), and for traces in Hoare's Communicating Sequential Processes (CSP). With this in mind we define, in this thesis, a class of high level Petri nets, High Level Petri Boxes, and provide for them a very general algebraic description language, the High Level Petri Box Algebra, with novel ideas for synchronisation, and including both refinement and recursion among its operators. We also begin on the (probably open-ended task of the) algebraic characterisation of High Level Petri Boxes. The major contribution of this thesis is a full behavioural characterisation of the High Level Petri Boxes which form the semantic domain of the algebra. Other contributions are: a very general method of describing communication protocols which extend the synchronisation algebras of Winskel; a recursive operator that preserves finiteness of state (the best possible, given the generality of the algebra); a refinement operator that is syntactic in nature, and for which the recursive construct is a behavioural fix-point; and a notion of behavioural equivalence which is a congruence with respect to a major part of the High Level Petri Box Algebra.
14
English, Sarah L. "Coloured Petri Nets for object-oriented modelling". Thesis, University of Brighton, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334740.
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VIEIRA, BRUNO LOPES. "EXTENDING PROPOSITIONAL DYNAMIC LOGIC FOR PETRI NETS". PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2014. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=24052@1.
Testo completoAbstract (sommario):
PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
PROGRAMA DE EXCELENCIA ACADEMICA
Lógica Proposicional Dinâmica (PDL) é um sistema lógico multi-modal utilizada para especificar e verificar propriedades em programas sequenciais. Redes de Petri são um formalismo largamente utilizado na especificação de sistemas concorrentes e possuem uma interpretação gráfica bastante intuitiva. Neste trabalho apresentam-se extensões da Lógica Proposicional Dinâmica onde os programas são substituídos por Redes de Petri. Define-se uma codificação composicional para as Redes de Petri através de redes básicas, apresentando uma semântica composicional. Uma axiomatização é definida para a qual o sistema é provado ser correto, e completo em relação à semântica proposta. Três Lógicas Dinâmicas são apresentadas: uma para efetuar inferências sobre Redes de Petri Marcadas ordinárias e duas para inferências sobre Redes de Petri Estocásticas marcadas, possibilitando a modelagem de cenários mais complexos. Alguns sistemas dedutivos para essas lógicas são apresentados. A principal vantagem desta abordagem concerne em possibilitar efetuar inferências sobre Redes de Petri [Estocásticas] marcadas sem a necessidade de traduzí-las a outros formalismos.
Propositional Dynamic Logic (PDL) is a multi-modal logic used for specifying and reasoning on sequential programs. Petri Net is a widely used formalism to specify and to analyze concurrent programs with a very intuitive graphical representation. In this work, we propose some extensions of Propositional Dynamic Logic for reasoning about Petri Nets. We define a compositional encoding of Petri Nets from basic nets as terms. Second, we use these terms as PDL programs and provide a compositional semantics to PDL Formulas. Then we present an axiomatization and prove completeness regarding our semantics. Three versions of Dynamic Logics to reasoning with Petri Nets are presented: one of them for ordinary Marked Petri Nets and two for Marked Stochastic Petri Nets yielding to the possibility of model more complex scenarios. Some deductive systems are presented. The main advantage of our approach is that we can reason about [Stochastic] Petri Nets using our Dynamic Logic and we do not need to translate it into other formalisms. Moreover our approach is compositional allowing for construction of complex nets using basic ones.
16
Wiley, Richard Paul. "Performance analysis of Stochastic Timed Petri Nets". Thesis, Massachusetts Institute of Technology, 1985. http://hdl.handle.net/1721.1/15002.
Testo completoAbstract (sommario):
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.
17
Cesco, Arnaldo. "Decidability Of Strong Equivalences For Finite Petri Nets". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amslaurea.unibo.it/23293/.
Testo completoAbstract (sommario):
Tra i vari modelli di sistemi concorrenti e distribuiti proposti, le reti di Petri finite sono uno dei più studiati ed adatti
alla descrizione di questo tipo di sistemi, poiché ne ricalcano le qualità distintive. Infatti, lo stato globale di una rete di Petri è formato da una collezione (detta marking) di stati locali
(detti token). L'esecuzione di una transizione è una trasformazione locale che riguarda solo una parte dei token in un marking. Pertanto, si può interpretare un token come un processo sequenziale ed un marking come un sistema distribuito che porta avanti una computazione più complessa all'interno della quale i processi possono cooperare o competere. Le equivalenze interessanti su reti di Petri quindi devono considerare vari aspetti del modello, quali concorrenza (e relazioni di causalità), scelte e ramificazioni, invarianti.
Nella prima parte del lavoro, si studiano equivalenze su reti Place/Transition (finite) safe e bounded. Sono riportati o provati alcuni risultati riguardanti due relazioni simili tra loro, che posseggono buona parte delle proprietà elencate sopra e considerano ogni esecuzione come un oggetto matematico a sè stante, detto processo. Le prove sono basate su una generalizzazione, per mezzo di indici, della tecnica di prova a marking ordinati usata da Vogler per dimostrare la decidibilità di fully-concurrent bisimilarity su reti safe.
Nella seconda parte del lavoro, si studiano equivalenze su reti Place/Transition (finite) ma con archi inibitori e senza limiti al numero di token che possono occupare un posto, dette reti PTI. In questo modello, i token possono non solo permettere l'esecuzione di una transizione, ma anche bloccarla. Si formula una equivalenza, pti-place bisimilarity, che estende conservativamente place-bisimilarity e se ne prova la decidibilità. Questa è la prima volta che una equivalenza è provata essere decidibile per reti PTI. Tuttavia, rispetto alle altre equivalenze note, non è coinduttiva.
18
Lucic, Diana. "On exact equilibrium distributions of stochastic Petri nets /". Title page, contents and summary only, 1990. http://web4.library.adelaide.edu.au/theses/09PH/09phl937.pdf.
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Coleman, James L. "Stochastic Petri Nets with product form equilibrium distributions /". Title page, contents and summary only, 1993. http://web4.library.adelaide.edu.au/theses/09PH/09phc6922.pdf.
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20
Djemame, Karim. "Distributed simulation of high-level algebraic Petri nets". Thesis, University of Glasgow, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301624.
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21
Usher, Michelle M. "A concurrent visual language based on Petri nets". Thesis, University of Liverpool, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366506.
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Cui, Qing Ming. "Parallel and distributed simulation of timed Petri nets". Thesis, University of Exeter, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.245946.
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Ng, Hoi Sum. "Petri nets for fault diagnosis and distribution automation". Thesis, University of Strathclyde, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366530.
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Bilinski, Krzysztof. "Application of Petri nets in parallel controller design". Thesis, University of Bristol, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.336830.
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Thal, Brent. "A Robust System Maturity Model Using Petri Nets". Thesis, The George Washington University, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10838208.
Testo completoAbstract (sommario):
Immature systems can be plagued by high costs, high risks, and schedule delays. System maturity models are utilized to quantitatively analyze a system’s readiness to indicate whether the system is prepared to proceed to the next acquisition phase during development. Most system maturity models are not robust enough to properly represent a system and assess its capabilities. Contemporary maturity models focus on individual technologies and fail to portray the importance of the integrations between technologies. System Readiness Level (SRL) was introduced to incorporate integration into a maturity assessment and to allow for a better evaluation of a system. However, adoption of SRL has been halted because of limitations due to the infancy of the model. This study demonstrates that by applying Petri Nets to SRL, a better maturity model is created, called Petri Net SRL (PNSRL). By incorporating Petri Nets, integrations are better represented, permitting a better system view that allows step-wise validation. PNSRL can be used with past SRL mathematical methods, which are simplified and easier to use. These enhancements offered by PNSRL allow an increased decision-making capability for projects. In this study, a capacity PNSRL method is developed to utilize Petri Net place capacities, offering a weighted SRL metric. Finally, PNSRL is verified against six SRL properties, showing that PNSRL is an acceptable maturity model.
26
Li, Yao Carleton University Dissertation Engineering Electrical. "The harmony operating system described by Petri Nets". Ottawa, 1986.
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27
Stojic, Ivan <1982>. "Algorithms for stationary analysis of stochastic Petri nets". Doctoral thesis, Università Ca' Foscari Venezia, 2016. http://hdl.handle.net/10579/10300.
Testo completoAbstract (sommario):
Stochastic Petri nets (SPN) are a Markovian formalism for qualitative and quantitative analysis of discrete event dynamic systems. Among other uses, they have been used extensively in performance evaluation of telecommunication systems, computer systems and networks. Analysis of an SPN model usually requires stationary analysis of a continuous-time Markov chain (CTMC) underlying the SPN, whose state space for many practical models is too large to be analysed by direct methods. This serious drawback is shared with many other modelling formalisms and is usually referred to as state space explosion. Usually simulation can be employed to analyse such models. An alternative is to restrict the SPN formalism to product-form SPNs, a class of nets whose unnormalised stationary probability distribution can be obtained in closed form, making stationary analysis much simpler. In this thesis we present algorithms for stationary analysis of SPN models based on efficient encoding of state spaces and transition functions by multi-way decision diagrams, an efficient data structure. After a short introduction to SPNs and their stationary analysis, we start with simulation of SPNs and present an algorithm for perfect simulation in SPNs that can be used to directly obtain samples from the stationary distribution. After this, we turn to simulation of product-form SPNs and present simulation stopping criteria that exploit the product-form property. Finally, we present an algorithm for fast computation of normalizing constant, needed for the normalisation of stationary probabilities in the analysis of product-form models.
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Turaev, Sherzod. "Petri net controlled grammars". Doctoral thesis, Universitat Rovira i Virgili, 2010. http://hdl.handle.net/10803/8799.
Testo completoAbstract (sommario):
Different types of regulated grammars have been introduced in order to supplement shortcomings of context-free grammars in applications preserving their elegant mathematical properties. However, the rapid developments in present day industry, biology, and other areas challenge to deal with various tasks which need suitable tools for their modelling and investigation. We propose Petri net controlled grammars as models for representing and analyzing of metabolic pathways in living cells where Petri nets are responsible for the structure and communication of the pathways, and grammars represent biochemical processes. On the other hand, the control by Petri nets has also theoretical interest: it extends possibilities to introduce and investigate concurrent control mechanisms in formal language theory. The thesis introduces various variants of Petri net controlled grammars using different types of Petri nets and investigates their mathematical properties such as computational power and closure properties.Los diferentes tipos de gramáticas con reescritura regulada han sido introducidas para complementar las deficiencias de las gramáticas libres del contexto en las aplicaciones, preservando sus propiedades matemáticas. Por otro lado, la rápida evolución la biología, y otras áreas actuales supone un reto para tratar de las tareas varias que necesitan las herramientas adecuadas para la elaboración de modelos e investigación. Proponemos gramáticas controladas por redes de Petri como modelos para representar y analizar los procesos bioquímicos en las células vivas donde redes de Petri son responsables de la estructura, y gramáticas representan los procesos generativos. Además, el control de redes de Petri también tiene interés teórico: amplía las posibilidades de investigar los mecanismos de control concurrente en la teoría de lenguajes formales. La tesis presenta distintas variantes de gramáticas controladas por redes de Petri e investiga sus propiedades matemáticas.
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Pocci, Marco. "Test and diagnosis of discrete event systems using Petri nets". Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4336/document.
Testo completoAbstract (sommario):
Le test d’identification d’état d’un système à événement discret (SED) a pour but d’en identifier l’état final, lorsque son état initial est inconnu. Une solution classique à ce problème, en supposant que le SED n’ait pas de sorties observables, consiste à déterminer une séquences de synchronisation, c.à-d., une séquence d’événements d’entrée qui conduit le SED sur un état connu. Ce problème a été résolu dans les années 60’ à l’aide des automates. L’objectif principal de cette thèse est d’utiliser les réseaux de Petri (RdP) pour obtenir une résolution plus optimal de ce problème et pour une plus large classe de systèmes.Initialement, nous montrons que la méthode classique peut être aisément étendue aux RdP synchronisés. Pour cette classe de réseaux non-autonomes, toute transition est associée à un événement d’entrée.L’approche proposée est générale, dans la mesure où elle s’applique à des RdP bornés arbitraires. Cependant, elle engendre le problème d’explosion combinatoire du nombre d’états. Pour obtenir des meilleures solutions, nous considérons une classe spéciale de RdP : les graphes d’état (GdE). Pour ces réseaux, nous considérons d’abord les GdE fortement connexes et proposons des approches pour la construction de SS, qui exploitent les propriétés structurelles du réseau en évitant ainsi une énumération exhaustive de l’espace d’état. Ces résultats s’étendent aux GdE non fortement connexes et à tout RdP synchronisé composé de GdE. Enfin, nous considérons la classe des RdP non bornés et proposons des séquences qui synchronisent le marquage des places non bornées. Une boîte à outils fournit toutes les approches décrites et est appliquée à des différents bancs d’essaiState-identification experiments are designed to identify the final state of a discrete event system (DES) when its initial state is unknown. A classical solution, assuming the DES has no observable outputs, consists in determining a synchronizing sequence (SS), i.e., a sequence of input events that drives the system to a known state. This problem was essentially solved in the 60’ using automata. The main objective of this thesis is to use Petri nets (PNs) for solving the state-identification problem more efficiently and for a wider class of systems.We start showing that the classical SS construction method based on automata can be easily applied to synchronized PNs, a class of non-autonomous nets where each transition is associated with an input event. The proposed approach is fairly general and it works for arbitrary bounded nets with a complexity that is polynomial with the size of the state space. However, it incurs in the state-space explosion problem.Looking for more efficient solutions, we begin by considering a subclass of PNs called state machines (SMs). We first consider strongly connected SMs and propose a framework for SS construction that exploits structural criteria, not requiring an exhaustive enumeration of the state space of the net. Results are further extended to larger classes of nets, namely non strongly connected SMs and nets containing SM subnets. Finally we consider the class of unbounded nets that describe infinite state systems: even in this case we are able to compute sequences to synchronize the marking of bounded places. A Matlab toolbox implementing all approaches previously described has been designed and applied to a series of benchmarks
30
Tarasyuk, Igor V. "Tau-Equivalences and Refinement for Petri Nets Based Design". Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-100370.
Testo completoAbstract (sommario):
The paper is devoted to the investigation of behavioral equivalences of concurrent systems modeled by Petri nets with silent transitions. Basic τ-equivalences and back-forth τ-bisimulation equivalences known from the literature are supplemented by new ones, giving rise to complete set of equivalence notions in interleaving / true concurrency and linear / branching time semantcis. Their interrelations are examined for the general class of nets as well as for their subclasses of nets without siltent transitions and sequential nets (nets without concurrent transitions). In addition, the preservation of all the equivalence notions by refinements (allowing one to consider the systems to be modeled on a lower abstraction levels) is investigated.
31
NISHIMURA, Yoshiyuki, Katsuaki ONOGI, Yutaka MATSUTANI, Yasushi MITSUYAMA e Susumu HASHIZUME. "Construction of Petri Nets from a Given Partial Language". Institute of Electronics, Information and Communication Engineers, 1996. http://hdl.handle.net/2237/14962.
Testo completo
32
Konios, Alexandros. "Modelling and verification of ambient systems using Petri nets". Thesis, University of Newcastle upon Tyne, 2015. http://hdl.handle.net/10443/3054.
Testo completoAbstract (sommario):
The expeditious development of technology in the past decades resulted in the introduction of concurrent systems that incorporate both ubiquitous and pervasive computing, the ambient systems. These systems are named after their ability to be completely embedded in the environment in which they operate and interact with the users, in a silent and non distracting way, facilitating the completion of their tasks. Hence, there is a growing need to introduce and develop formal techniques for computational models capable of faithfully modelling the behaviour of these systems. One way of capturing the intricate behaviours of the ambient systems is to use Petri nets, which are a modelling language that is used for the representation and analysis of concurrent systems. Within the domain of rigorous system design, verification of systems effectively checks and guarantees the correctness of the examined models with respect to the specification. This work investigates the modelling and the analysis of ambient systems using Petri nets. To examine the modelling of these systems, their taxonomy into Ambient Guidance Systems and Ambient Information Systems is carried out and a case study is used for the modelling of each category. To model ambient systems, the step-modelling approach and a variant class of Coloured Petri Nets, the Ambient Petri Nets (APNs), are introduced. Step modelling approach focuses on the interaction between the system and the user and Ambient Petri Nets is a class of nets with colour-sensitive inhibitor arcs that is used especially for the structural and behavioural representation of ambient systems. For the modelling of general ambient systems, the compositionality of the Ambient Petri Nets is used. To verify the correctness of the produced Ambient Petri Nets models, the introduction of the Transformed Ambient Petri Nets class that has no colour-sensitive inhibitor arcs is required since Charlie and generally most of the existing verification tools do not support the analysis of inhibitor nets. To address this problem, a construction is defined to translate the Ambient Petri Nets into Transformed Ambient Petri Nets. Afterwards, the Step Transition Systems are used to prove the behavioural equivalence of the nets that are associated through the construction. Subsequently, the Transformed Ambient Petri Nets models of the chosen case studies are verified against model checking and qualitative properties. For the first category, Computation Tree Logic (CTL) is used to check the models against important properties of the ambient systems that are related to their features and their general functioning. Finally, qualitative properties consider fundamental structural and behavioural properties of Petri nets that provide useful outcome about the systems under consideration.
33
Rada, Irina. "Distributed generation of state space for timed Petri nets". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0018/MQ54952.pdf.
Testo completo
34
ONOGI, Katsuaki, Hidekazu KURIMOTO, Susumu HASHIZUME, Takashi ITO e Tomoyuki YAJIMA. "Control of Batch Processes Based on Hierarchical Petri Nets". Institute of Electronics, Information and Communication Engineers, 2004. http://hdl.handle.net/2237/14963.
Testo completo
35
Bagga, Kunwarjit Singh. "A study of deadlocks and traps in petri nets". Virtual Press, 1988. http://liblink.bsu.edu/uhtbin/catkey/544009.
Testo completoAbstract (sommario):
Petri nets are used as models in the study of networks involving information flows. Petri nets have also turned out to be useful in the study of many asynchronous concurrent systems.In this thesis, the notions of deadlocks, traps, and liveness are considered from a graph theoretic viewpointA characterization of minimal deadlocks and traps in Petri nets is obtained. For the complete Petri nets, alternative characterizations of deadlocks and traps are obtained. Necessary and sufficient conditions are obtained for complete Petri nets to be deadlock free. Similar conditions for trap free complete Petri nets are also determined.Department of Computer Science
36
Loch, Fredrik. "Proving liveness properties of concurrent programs using petri-nets". Thesis, Umeå universitet, Institutionen för datavetenskap, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-92803.
Testo completoAbstract (sommario):
With the increased scale of distributed computations the complexity of liveness proofs have increased. In this paper we endeavor to simplify the process of verifying a concurrent system using well know modeling techniques. The choice of modeling tool as well as the proof is based on future scalability and automation. We translate the formal proof to a petri-net representation and use this to verify basic algorithms. We show that the formal proof of liveness stated by Owiki and Lamport can be adapted to petri-nets. We also show a modification to petri-nets for increased granularity in loop modeling. This is used to clarify the translation of the original proof to our petri-net representation. With these results we discuss the usefulness of our approach and compare it to other methods of ensuring liveness.
37
Grecco, Albert J. "AdaFlow: the automation of software analysis using Petri Nets". Thesis, Monterey, California. Naval Postgraduate School, 1988. http://hdl.handle.net/10945/22853.
Testo completoAbstract (sommario):
There is considerable interest in the development of Ada-based, automated software tools to aid in the development and testing of embedded, real-time software. The Naval Postgraduate School has already implemented automated Ada metric tools at the request of the Naval Weapons Center, China Lake. This thesis is the preliminary work for a new automated software analysis tool entitled AdaFlow. This tool, which is written in Ada, takes Ada programs as input, and translates the source code to a Petri net model. This Petri net model provides the user with the capability to perform automated, interactive analysis of Ada programs for properties such as safety and deadlocks. Recommendations for future work in this area are included.(KR)
38
Santini, Marie. "Analysis of asynchronous iterative algorithms using timed Petri nets". Thesis, University of Salford, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.360405.
Testo completo
39
Sananikone, Dang S. "Cosynthesis of embedded systems using coloured interpreted petri nets". Thesis, University of Aberdeen, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.320764.
Testo completoAbstract (sommario):
The rising complexity in systems design, and the shift in the hardware/software functionality boundary has spurred research into development of EDA (Electronic Design Automation) tools at the systems level. Codesign is a methodology that proposes an integrated approach to systems design unifying both hardware and software approaches. Cosynthesis is a major field of research within codesign; cosynthesis takes a behavioural description and generates a hardware/software partition which satisfies system constraints. Current research is concerned with the automatic partitioning of systems. COSYN was developed to address the cosynthesis of embedded systems. A CIPN (Coloured Interpreted Petri Net) is used to model multiple processes and interprocess communication. The partitioning algorithm, which adopts a fine-grained approach to system partitioning (it considers moving nodes at the basic block level), is based on selecting blocks based on their potential speedup and extra hardware requirements, using hardware and software execution time estimators. The interdependence between interprocess communication primitives is exploited to achieve a better hardware/software partition. Results for an input example pdi are given which illustrate the benefits of the approach presented in this thesis.
40
Hillion, H. P. (Herve P. ). "Performance evaluation of decisionmaking organizations using Timed Petri Nets". Thesis, Massachusetts Institute of Technology, 1986. http://hdl.handle.net/1721.1/15071.
Testo completoAbstract (sommario):
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1986.MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING
Bibliography: leaves 155-156.
by Herve P. Hillion.
M.S.
41
Remy, Pascal A. "On the generation of organizational architectures using Petri nets". Thesis, Massachusetts Institute of Technology, 1986. http://hdl.handle.net/1721.1/14937.
Testo completoAbstract (sommario):
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1987.MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING.
Bibliography: leaves 185-187.
by Pascal A. Remy.
M.S.
42
Brown, Carolyn T. "Linear logic and Petri nets : categories, algebra and proof". Thesis, University of Edinburgh, 1990. http://hdl.handle.net/1842/15424.
Testo completoAbstract (sommario):
This thesis explores three ways in which linear logic may be used to define a specification language for Petri nets, by giving precise correspondences, at different levels, between linear logic and Petri nets. Firstly, we define categories NC by analogy with de Paiva's dialectica categories GC. The category NSet has as objects the elementary Petri nets and morphisms refinement maps. We show that GC induces in NC sufficient structure for NC to be a sound model of linear logic. We demonstrate the computational significance of the net constructors induced by the interpretations in NSet of the linear connectives ®, A,-o,© and (-)-1-. Our framework unifies several existing approaches to categories of nets, and gives a model of full linear logic based on nets. Secondly, we show that the possible evolutions of a net generate a quan-tale. Quantales are algebraic models of linear logic. Further, we show that certain restrictions on nets, including being safe or bounded, rise as subquantales induced by suitable conuclei. This approach allows us to give a sound semantics for linear logic using sets of markings of a given net. Thus the probability of certain assertions in linear logic corresponds to properties of nets. Thirdly, we define a semantics for a fragment of linear logic £„ in terms of nets, by giving a partial function from formulae of linear logic to nets. This semantics is complete and sound where defined. Further, we show that whenever a net N can evolve to a net N', there is a canonical proof in to that the formula interpreted by N entails the formula interpreted by N'. A canonical proof expresses the causal dependencies of a net in a precise way, using the (Cut) rule. This approach allows us to use the techniques of proof theory to study the evolution of nets.
43
PAYAL. "ON SIGNED PETRI NETS". Thesis, 2023. http://dspace.dtu.ac.in:8080/jspui/handle/repository/20370.
Testo completoAbstract (sommario):
In today’s complex scenario of technological advancement, the role of
event-driven discrete dynamical systems have an impact on man’s
ability to fast-forward the futuristic technologies that are likely to bring
unimaginable progress in our time, and near, far futures. One such
great innovation that inspired this thesis is the "Theory of Petri nets", a
modeling tool for event-driven discrete dynamical systems.
The study of Petri nets and its various extensions that have
developed over time is one of the most active and vibrant areas of
research in current time, owing to its applications in the fields of
engineering and sciences. The structure of Petri nets is a directed
bipartite graph. They can be used as a graphical as well as a
mathematical tool. As a graphical tool, they are easier to understand
and interactive in nature while as a mathematical tool, they can be
used to formulate state and algebraic equations for easier calculation
and analysis.
The notion of Petri net was discovered by Carl Adam Petri at a
mere age of 13 to describe chemical processes. More formally, it was
described in his thesis "Communication with Automata" in 1962,
submitted to the Science Faculty of Darmstadt Technical University.
Due to their dynamic nature, Petri nets soon became useful in
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xii CONTENTS
modeling of asynchronous, distributed, concurrent, parallel,
nondeterministic, and/or stochastic systems. Thus, various extensions
to Petri nets have been introduced viz. Continuous Petri nets,
Stochastic Petri nets, Timed Petri nets, Object Petri nets, Hybrid Petri
nets, Workflow nets, Fuzzy Petri nets, Lending Petri nets,
Multidimensional Petri nets etc., in order to better incorporate the
characteristics of the system to be modeled. The Petri nets and their
extensions have been widely used in various fields. Logic Petri nets
(LPNs) have been defined as high level Petri nets, to describe batch
processing functions and passing value indeterminacy in cooperative
systems.
The thesis entitled “On Signed Petri Nets” contains seven chapters.
Chapter 1 titled "General Introduction" provides a brief review of
Petri net theory. It provides the contributions of various researchers
who have extended the theory of Petri nets after its introduction by
Carl Adam Petri. A brief survey of the Petri nets research is given. The
various extensions and applications of Petri nets in some of the fields
have been discussed in brief. Thus, this chapter builds up a
background and motivation behind the thesis work along with the tools
required to achieve the goals.
Chapter 2 titled "Signed Petri net" describes the extension of Petri
nets called Signed Petri net and the related terminology. The proposed
concept is inspired from signed graphs and Petri nets and can be
considered as an amalgamation of the two, utilizing the properties of
both. The basic properties and terms associated with signed Petri nets
are defined. The applications of signed Petri nets in message
transmission system and production unit are discussed. Lastly, it is
CONTENTS xiii
shown how a Logic Petri nets can be simulated using a signed Petri
nets by merely changing the execution rules of a signed Petri nets.
These modified signed Petri nets are called a Logic signed Petri nets.
These concepts clearly demonstrate the advantages of the proposed
approach of signed Petri nets. This chapter is published as a research
paper "An introduction to Signed Petri net, Journal of Mathematics,
(2021)".
In Chapter 3 titled "Analysis of Signed Petri nets", the work of
previous chapter has been extended. Mere modeling of system is of
no use unless the modeled system is interpreted, which led to the
introduction of analysis techniques for analyzing signed Petri nets. Two
techniques for analysis are provided: Reachability Tree and Matrix
equations with main focus on matrix equations. An actual case
scenario of a restaurant model is given and analyzed using the
techniques given in the chapter. The benefits of using a signed Petri
nets to model the restaurant system rather than using traditional Petri
nets are also given. This chapter has been accepted with title
"Analysis of Signed Petri net, International Journal of Computing
Science and Mathematics, (2020)".
In Chapter 4 titled "Structural Matrices for Signed Petri nets",
several matrices which show the relationship between transitions and
places have been introduced. Three different matrices are defined by
different products of the adjacency matrix of signed Petri nets with its
transpose and with itself. In fact, if all these matrices are given, the
signed Petri net structure can be obtained after analyzing them. Such
matrices are useful because while creating algorithms for various
procedures and results, it is not possible to extract data from a graph
xiv CONTENTS
rather all the information can be provided in the form of matrices. The
matrices are further utilized to find a directed cycle in signed Petri nets.
Various subclasses of signed Petri nets along with their
characterizations using the structural matrices have been introduced.
This chapter is published with title "Structural Matrices for Signed Petri
net, AKCE International Journal of Graphs and Combinatorics,
(2022)".
In Chapter 5 titled "Structural and Dynamical Balanceness in
Signed Petri net", the concept of structural and dynamical balanceness
have been introduced. A structurally balanced signed Petri net has
been defined and its characterization is given. It is shown how the
dynamical balanceness approach is advantageous in analyzing social
interactions, since all the signed graphs (directed or undirected) can
be simulated by firing of different sequence of transitions in a single
signed Petri net. Also, dynamics associated with a system can be
easily represented using signed Petri nets rather than a signed graph.
The equivalence between balanced signed graphs and dynamically
balanced signed Petri nets is established. This chapter comprises the
result from the research papers "An introduction to Signed Petri net,
Journal of Mathematics, (2021) and Social Interactions through Signed
Petri net, Communicated".
In Chapter 6 titled "Domination in Signed Petri nets", the concept
of Domination has been introduced as such a concept doesn’t exist for
the dynamic systems. It can be seen with the help of the applications of
finding the highest and lowest ranking officials in an institute based on a
certain activity, producer- consumer problem, searching of food by bees
and finding similarity in research papers, how the proposed concept is
CONTENTS xv
beneficial. The work in this chapter is in the research paper "Domination
in Signed Petri net, https://arxiv.org/abs/2001.04374, (2020)".
Chapter 7 titled "Conclusion and Future Scope" concludes the
thesis work and gives a future research plan. In the research work, an
extension of Petri nets called as "Signed Petri nets" has been
proposed. Various results have been obtained in our present work
along with some real-life applications where the proposed research
can be used. The authors are of the view that this extension has a
great scope in the study of various dynamic systems as well as
modeling real-life applications. In future, the thesis work will be
extended by utilizing the signed Petri nets in modeling various
scenarios and analyzing the modeled system.
Lastly, the bibliography is given to appreciate those who have made
it possible to understand and use the vast theory of Petri nets. A list of
author’s publications is also given at the end of the thesis.
44
Nicdao, Jose Marcelino Arrozal, e 廖扶西. "Fundamental Structures in Petri Nets". Thesis, 2000. http://ndltd.ncl.edu.tw/handle/21450361311514773457.
Testo completoAbstract (sommario):
碩士國立政治大學
資訊管理學系
88
The thesis contributes to the theoretical study of Petri net theory. We conduct boundedness and liveness structural analysis of Synchronized Choice nets (SNC) based on fundamental structures in Petri nets and identified as first-order structures. By studying these structures, the study proposes two ways of preserving good properties: addition of second-order structures or other asymmetric structures. Liveness of these new SNC nets is studied based on the concept of siphons and traps. We prove that SNC nets thus formed are structurally bounded and live. The thesis extends this class of nets to those with pure TP and PT first-order structures and explores its structural and marking conditions. Based on this, we introduce a new class of Synchronized Choice nets called Expanded Synchronized Choice nets.
45
XIE, GUI-YUAN, e 謝貴淵. "Transforming programs into petri Nets". Thesis, 1992. http://ndltd.ncl.edu.tw/handle/07508189037045719130.
Testo completo
46
Lin, Yuh-Der, e 林育德. "Parallel Timed Petri Nets Simulator". Thesis, 1995. http://ndltd.ncl.edu.tw/handle/19679176843138246348.
Testo completoAbstract (sommario):
碩士淡江大學
資訊工程研究所
83
Petri Nets（PN）是一種以正規方法（formal method）來描述和分析系 統行為的工具，特別是針對具有同時性（concurrent）與非同步特性 asynchronous）的系統。將時間引入Petri Nets之中（即所謂的Timed Petri Nets），則更能有效地對所描述的系統做作效能評估（ performance evaluation），例如Timed Petri Nets已被廣泛地應用在對 分散式系統（ distributed system）的效能分析上。隨著所描述系統之 複雜度（complexity）不斷地擴增，Petri Nets的網路結構（net structure）也變得更為複雜，以analytical的方式對Petri Nets作分析 則因記憶體（memory）與複雜度要求過高而變得不可行，而傳統上採用離 散事件模擬（discrete-event simulation）方式的循序Timed Petri Nets模擬器（sequential Timed Petri Nets simulator）也不能滿足我 們對執行時間上嚴格的要求，因此我們希望能將模擬器平行化（ parallelize），即將同一時間內所能處理的event個數增加，使模擬器在 多處理器（multiprocessor）之架構下能達到加速（speedup）的效果。 傳統上在討論離散事件模擬平行化時有兩種方法廣被使用：時間分區間法 （temporal decomposition method）與空間分區域法（spatial decomposition method)，這兩種方法各有其優點，我們的平行Timed Petri Nets模擬器將採用空間分區域法中的distributed simulation mechanism來做模擬，同時我們將對平行化時所遭遇的問題，如切割 partition）、訊息傳遞（message passing）、模擬結果收集 ]simulation results collection）等尋求解決之道。最後我們將在 Transputer之多處理器上實作一個平行Timed Petri Nets 模擬器。 Timed Petri Nets is a modeling tool that can be used to describe and analyze the behaviors of a system with characteristics such as concurrencyand asynchronism. Because the complexity and size of a Timed Petri Netsmodel for a physical system are steadily increasing, to analyze a very complex net model by using existing analytical methods has become impossible. Alternatively, a discrete-event Timed Petri Nets simulator can be used to obtain approximated net solutions. The only main drawback is the longsimulation run time. In order to reduce the simulation run time, severalmethods have emerged to construct a parallel simulator counterpart. There are two methodologies often used in parallel discrete-event simulation, that is, the temporal decomposition method and the spatial decomposition method. We use one of the spatial decomposition methods, the distributed simulation mechanism, in constructing our parallel Timed Petri Nets simulator.Problems such as partitioning, messages passing, and collecting of simulationresults have also been solved. Finally we have implemented a parallel Timed Petri Nets simulator on a Transputer network. More study on performance evaluation of our simulators will be conducted.
47
Shiau, Yuh-Shin, e 蕭毓欣. "New Methods for Knowledge Representation and Reasoning Using Extended Fuzzy Petri Nets and Time Petri Nets". Thesis, 1997. http://ndltd.ncl.edu.tw/handle/59329606435635902582.
Testo completoAbstract (sommario):
碩士國立交通大學
資訊科學學系
86
In this thesis, we present an extended fuzzy Petri net model to model fuzzy IF-THEN rules and fuzzy IF-THEN-ELSE rules of rule- based systems. We also develop an efficient algorithm for performing vague reasoning automatically based on the extended fuzzy Petri net model. The proposed algorithm allows the computers to perform reasoning in a more flexible and more intelligent manner. Based on the proposed vague reasoning algorithm, we have implemented a vague reasoning system on a Pentium PC for performing vague reasoning automatically. Furthermore, we propose a method to describe the relationships between states and events for temporal knowledge representation and reasoning using time Petri nets. We also propose an algorithm to infer the consistency of the temporal knowledge based on the time Petri nets. Based on the proposed temporal reasoning algorithm, we have implemented a temporal reasoning system on a Pentium PC to check the consistency of the temporal knowledge.
48
Fan, Chu-Kai, e 范崇愷. "Elevator Dynamic Simulation Using Petri Nets". Thesis, 1998. http://ndltd.ncl.edu.tw/handle/41371855756788488008.
Testo completoAbstract (sommario):
碩士國立成功大學
航空太空工程學系
86
The aim of this dissertation is to realize the elevator discrete event dynamics duo to the traveling request using Petri nets. Based on the proposed representation scheme, the efficiency of elevator group can be analysed. Properties of the Petri nets are introduced. An extended colored Petri net is proposed to construct elevator dynamic model. The proposed single elevator dynamic model can be modularized and extended to multi-elevator cases effectively and efficiently. C- program is used to simulate the elevator dynamics presented by Petri nets. From the simulation results, the key issue to enhance elevator group performance can be further investigated. The methodology and simulation environment provided in this dissertation are beneficial to the study of elevator group scheduling.
49
She, Ta-Lun, e 佘達綸. "VoIP Fault Detection Using Petri Nets". Thesis, 2007. http://ndltd.ncl.edu.tw/handle/89673634186161166836.
Testo completoAbstract (sommario):
碩士逢甲大學
資訊工程所
95
Voice over Internet Protocol (VoIP) is not limited to the transmission of voice packets, but integrates video, voice mail, and multimedia, all at a low cost. An increasing number of agencies, enterprises, and schools are designing and deploying IP telephony networks. Session Initiation Protocol Internet Protocol Private Branch Exchanges (SIP IP-PBXs) and Internet Telephony Gateways (ITGs) can connect with other Internet Telephony Service Providers (ITSPs) to take advantage of tremendous savings in long-distance and international calling. Currently one obstacle to total replacement of Public Switched Telephone Networks (PSTNs) by VoIP is the limited management control over VoIP faults. Since VoIP must often establish connections under uncontrollable conditions, it is necessary VoIP’s protocols (such as H.323 and SIP) to provide network management with detailed information concerning faults. Existing management systems only provide call detail records, dial plan settings, and call access control. Existing systems do not provide efficient and immediate call quality monitoring, which causes users to question the maturity of VoIP technology. In this paper, we proposed a fault detection system to manage SIP-based VoIP systems. We collected messages exchanged between SIP User Agents (UA) and SIP Servers. When each call was established from the calling UA to the receiving UA, Simple Network Management Protocol (SNMP) transmitted relevant information to our fault detection system. A Timing Constraint Petri Net (TCPN) model monitored calls; when faults were detected, the management system searched the knowledge base, determined an explanation for each fault, and automatically e-mailed the relevant explanation, along with suggested solutions, to management personnel. The system as developed provides timely management of person-to-person calls; we suggest that future research could usefully extend this technology to conference calls.
50
Wang, Bo Yao, e 王柏堯. "Verifying temporal properties of petri nets". Thesis, 1994. http://ndltd.ncl.edu.tw/handle/45568210926471806215.
Testo completo