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Analyzing safety and fault tolerance using time Petri nets
The application of time Petri net modelling and analysis techniques to safety-critical real-time systems is explored and procedures described which allow analysis of safety, recoverability, and fault tolerance. These procedures can be used to help determine software requirements, to guide the use of fault detection and recovery procedures, to determine conditions which require immediate miti gating action to prevent accidents, etc. Thus it is possible to establish important properties duing the synthesis of the system and software design instead of using guesswork and costly a posteriori analysis
TIME EXTENSIONS OF PETRI NETS FOR MODELLING AND YERIFICATION OF HARD REAL-TIME SYSTEMS
The main aim ofthepaper is apresentation oftime extensions ofPetri nets appropriate for modelling and analysis o f hard real-time systems. It is assumed, that the extensions must provide a model o f time flow, an ability to force a transition to fire within a stated timing constraint (the so-called the strongfiring rule), and timing constraints represented by inte- rvals. The presented survey includes extensions o f classical Place/Transition Petri nets, as well as the ones applied to high-level Petri nets. An expressiveness o f each time extension is illustrated using simple hard real-time system. The paper includes also a brief description o f analysis and verification methods related to the extensions, and a survey o f software tools supporting modelling and analysis o f the considered Petri nets
Applying Formal Methods to Networking: Theory, Techniques and Applications
Despite its great importance, modern network infrastructure is remarkable for
the lack of rigor in its engineering. The Internet which began as a research
experiment was never designed to handle the users and applications it hosts
today. The lack of formalization of the Internet architecture meant limited
abstractions and modularity, especially for the control and management planes,
thus requiring for every new need a new protocol built from scratch. This led
to an unwieldy ossified Internet architecture resistant to any attempts at
formal verification, and an Internet culture where expediency and pragmatism
are favored over formal correctness. Fortunately, recent work in the space of
clean slate Internet design---especially, the software defined networking (SDN)
paradigm---offers the Internet community another chance to develop the right
kind of architecture and abstractions. This has also led to a great resurgence
in interest of applying formal methods to specification, verification, and
synthesis of networking protocols and applications. In this paper, we present a
self-contained tutorial of the formidable amount of work that has been done in
formal methods, and present a survey of its applications to networking.Comment: 30 pages, submitted to IEEE Communications Surveys and Tutorial
A methodology for complex embedded systems design : Petri nets within a UML approach
This paper focus mainly on the analysis phase, describing a UML-based approach for designing complex embedded systems, and specifically the usefulness of using shobi-PN v2.0 specifications, a Petri net extension, for modelling the dynamic behaviour. A relative complex case study is used to show the usefulness of the suggested specification approach
An evolutionary approach to the use of Petri net based models: from parallel controllers to HW/SW co-design
"A workshop within the 19th International Conference on Applications and Theory of Petri Nets - ICATPN’1998"The main purpose of this article is to present how Petri Nets (PNs) have been used for hardware design at our research laboratory. We describe the use of PN models to specify synchronous parallel controllers and how PN speci cations can be extended to include the behavioural description of the data path, by using object-oriented concepts. Some hierarchical mechanisms which deal with the speci cation of complex digital systems are highlighted. It is described a design flow that includes, among others, the automatic generation of VHDL code to synthesize the control unit of the system. The use of PNs as part of a multiple-view model within an object-oriented methodology for hardware/software codesign is debated. The EDgAR-2 platform is
considered as the recon gurable target architecture for implementing the systems and its main characteristics are shown
An evolutionary approach to the use of petri net based models : from parallel controllers to Hw/Sw codesign
The main purpose of this article is to present how Petri Nets (PNs) have been
used for hardware design at our research laboratory. We describe the use of PN
models to specify synchronous parallel controllers and how PN specifications
can be extended to include the behavioural description of the data path, by using
object-oriented concepts. Some hierarchical mechanisms which deal with the
specification of complex digital systems are highlighted. It is described a design
flow that includes, among others, the automatic generation of VHDL code to synthesize
the control unit of the system. The use of PNs as part of a multiple-view
model within an object-oriented methodology for hardware/software codesign
is debated. The EDgAR-2 platform is considered as the reconfigurable target
architecture for implementing the systems and its main characteristics are shown
A model driven approach to analysis and synthesis of sequence diagrams
Software design is a vital phase in a software development life cycle as it creates a blueprint for the implementation of the software. It is crucial that software designs are error-free since any unresolved design-errors could lead to costly implementation errors. To minimize these errors, the software community adopted the concept of modelling from various other engineering disciplines. Modelling provides a platform to create and share abstract or conceptual representations of the software system – leading to various modelling languages, among them Unified Modelling Language (UML) and Petri Nets. While Petri Nets strong mathematical capability allows various formal analyses to be performed on the models, UMLs user-friendly nature presented a more appealing platform for system designers. Using Multi Paradigm Modelling, this thesis presents an approach where system designers may have the best of both worlds; SD2PN, a model transformation that maps UML Sequence Diagrams into Petri Nets allows system designers to perform modelling in UML while still using Petri Nets to perform the analysis. Multi Paradigm Modelling also provided a platform for a well-established theory in Petri Nets – synthesis to be adopted into Sequence Diagram as a method of putting-together different Sequence Diagrams based on a set of techniques and algorithms
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