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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

The harmony operating system described by Petri Nets.

Li, Yao, Carleton University. Dissertation. Engineering, Electrical. January 1986 (has links)
Thesis (M. Eng.)--Carleton University, 1986. / Also available in electronic format on the Internet.
12

Towards resilient supply chain networks

Muddada, Raja Ram Mohan Roy 20 September 2010 (has links)
In the past decade, events like 9/11 terror attacks, the recent financial crisis and other major crisis has proved that there is strong interaction and interdependency of a supply chain network with its external environments in various channels and thus a need to focus on building resiliency (in short, the ability of the system to recover from damage or disruption) of the entire network system. Although literature has discussed some way of improving resiliency of an individual firm which is a member of the network system, it lacked to capture a holistic view of the supply chain network. Pertaining to this observation, this work proposes to improve resiliency of a supply chain network from a systems perspective rather concentrate on an individual firm. For this purpose, this thesis proposes a conceptual framework to promote early identification and timely information of the disruptions arising in a supply chain network and timely sharing of this information among all the members of the network. The key principle emphasized in this thesis is that recovery from an inevitable disruption has a better possibility if a member of the supply chain network has an early indication or knowledge of the upcoming disruption. A discrete event dynamic system simulation tool called Petri nets is utilized to realize the proposed conceptual framework. Furthermore, the practical benefits and implications of the proposed model and tool are demonstrated with help of two case studies. This thesis has several contributions to the field of operation management and supply chain. First, a new paradigm for supply chain management to avoid large scale failures such as financial crisis is available to the field, which may be applied by governments or regulatory bodies. Second, a new framework which allows for a quantitative analysis of failures of an entire supply chain network is available to the field, which is easy to be used. Third, a novel application of Petri nets to this new problem in supply chain management is available.
13

Engineering communicative distributed safety-critical systems

Birkinshaw, Carl Ian January 1995 (has links)
No description available.
14

Towards resilient supply chain networks

Muddada, Raja Ram Mohan Roy 20 September 2010
In the past decade, events like 9/11 terror attacks, the recent financial crisis and other major crisis has proved that there is strong interaction and interdependency of a supply chain network with its external environments in various channels and thus a need to focus on building resiliency (in short, the ability of the system to recover from damage or disruption) of the entire network system. Although literature has discussed some way of improving resiliency of an individual firm which is a member of the network system, it lacked to capture a holistic view of the supply chain network. Pertaining to this observation, this work proposes to improve resiliency of a supply chain network from a systems perspective rather concentrate on an individual firm. For this purpose, this thesis proposes a conceptual framework to promote early identification and timely information of the disruptions arising in a supply chain network and timely sharing of this information among all the members of the network. The key principle emphasized in this thesis is that recovery from an inevitable disruption has a better possibility if a member of the supply chain network has an early indication or knowledge of the upcoming disruption. A discrete event dynamic system simulation tool called Petri nets is utilized to realize the proposed conceptual framework. Furthermore, the practical benefits and implications of the proposed model and tool are demonstrated with help of two case studies. This thesis has several contributions to the field of operation management and supply chain. First, a new paradigm for supply chain management to avoid large scale failures such as financial crisis is available to the field, which may be applied by governments or regulatory bodies. Second, a new framework which allows for a quantitative analysis of failures of an entire supply chain network is available to the field, which is easy to be used. Third, a novel application of Petri nets to this new problem in supply chain management is available.
15

A three-dimensional modeling approach to Petri network design and modeling

Dance, Linda Kaye, January 2001 (has links) (PDF)
Thesis (M.E.)--University of Florida, 2001. / Title from first page of PDF file. Document formatted into pages; contains xiii, 103 p.; also contains graphics. Vita. .Avi file containing movie (referred to in abstract) is missing. Includes bibliographical references (p. 101-102).
16

Mobiliosios informavimo sistemos tyrimas / Exploration of mobile information system

Kaškelevičius, Darius 24 May 2005 (has links)
This work is dedicated to the making and research of mobile information system. Following tasks were completed in order to tackle this problem: mobile information system processes analysis; uml modeling analysis; formal modeling methods analysis; composition of system model; system model verification.
17

A study of deadlocks and traps in petri nets

Bagga, Kunwarjit Singh January 1988 (has links)
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
18

Synthesis and axiomatisation for structural equivalences in the Petri Box Calculus

Hesketh, Martin January 1998 (has links)
The Petri Box Calculus (PBC) consists of an algebra of box expressions, and a corresponding algebra of boxes (a class of labelled Petri nets). A compo- sitional semantics provides a translation from box expressions to boxes. The synthesis problem is to provide an algorithmic translation from boxes to box expressions. The axiomatisation problem is to provide a sound and complete axiomatisation for the fragment of the calculus under consideration, which captures a particular notion of equivalence for boxes. There are several alternative ways of defining an equivalence notion for boxes, the strongest one being net isomorphism. In this thesis, the synthesis and axiomatisation problems are investigated for net semantic isomorphism, and a slightly weaker notion of equivalence, called duplication equivalence, which can still be argued to capture a very close structural similarity of con- current systems the boxes are supposed to represent. In this thesis, a structured approach to developing a synthesis algorithm is proposed, and it is shown how this may be used to provide a framework for the production of a sound and complete axiomatisation. This method is used for several different fragments of the Petri Box Calculus, and for gener- ating axiomatisations for both isomorphism and duplication equivalence. In addition, the algorithmic problems of checking equivalence of boxes and box expressions, and generating proofs of equivalence are considered as extensions to the synthesis algorithm.
19

Verifying temporal properties of systems with applications to petri nets

Bradfield, Julian Charles January 1991 (has links)
This thesis provides a powerful general-purpose proof technique for the verification of systems, whether finite or infinite. It extends the idea of finite local model-checking, which was introduced by Stirling and Walker: rather than traversing the entire state space of a model, as is done for model-checking in the sense of Emerson, Clarke et al. (checking whether a (finite) model satisfies a formula), local model-checking asks whether a particular state satisfies a formula, and only explores the nearby states far enough to answer that question. The technique used was a tableau method, constructing a tableau according to the formula and the local structure of the model. This tableau technique is here generalized to the infinite case by considering sets of states, rather than single states; because the logic used, the propositional modal mu-calculus, separates simple modal and boolean connectives from powerful fix-point operators (which make the logic more expressive than many other temporal logics), it is possible to give a relatively straightforward set of rules for constructing a tableau. Much of the subtlety is removed from the tableau itself, and put into a relation on the state space defined by the tableau-the success of the tableau then depends on the well-foundedness of this relation. This development occupies the second and third chapters: the second considers the modal mu-calculus, and explains its power, while the third develops the tableau technique itself The generalized tableau technique is exhibited on Petri nets, and various standard notions from net theory are shown to play a part in the use of the technique on nets-in particular, the invariant calculus has a major role. The requirement for a finite presentation of tableaux for infinite systems raises the question of the expressive power of the mu-calculus. This is studied in some detail, and it is shown that on reasonably powerful models of computation, such as Petri nets, the mu-calculus can express properties that are not merely undecidable, but not even arithmetical. The concluding chapter discusses some of the many questions still to be answered, such as the incorporation of formal reasoning within the tableau system, and the power required of such reasoning.
20

PEM - Modelo de Ejecución Paralela basado en redes de Petri

Wolfmann, Aaron Gustavo Horacio January 2015 (has links)
El objetivo de la tesis es la definición de un modelo de ejecución paralelo, que basado en la representación de un algoritmo paralelo con Redes de Petri, permita a un conjunto flexible de procesadores independientes entre sí, ejecutar el algoritmo en forma asíncrona con altos rendimientos y que el programador tenga capacidad de ajustar los parámetros de ejecución en vista de mejoras de rendimiento. Los fundamentos son claros: se desea contar con una herramienta de ejecución de programas paralelos que permita modelar el algoritmo, y pasar del modelo a la ejecución asíncrona preservando el modelo. Las Redes de Petri son la herramienta básica e indiscutiblemente pertinente para lograr el objetivo. Un desafío es cubrir la brecha o gap existente entre el modelado y una ejecución del programa paralelo de rendimientos aceptables y escalables.Para ello, debe existir una vinculación del modelo con un conjunto de unidades de procesamiento que corran en paralelo.

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