The PROTEAN protocol emulation and analysis computer aid is presented. It is based on a formal specification technique called numerical Petri nets (NPNs), and provides both graphical (color) and textual interfaces to the protocol designer. NPN specifications may be created, stored, appended to other NPNs, structured, edited, listed, displayed, and analyzed. Interactive simulation, exhaustive reachability analysis, and several directed graph analysis facilities are described. Specification languages are compared, with concentration on extended finite state machines and high-level Petri nets. Both the NPN and PROTEAN facilities are described and illustrated with a simple example. The application of PROTEAN to complex examples is mentioned briefly. Work towards a comprehensive protocol engineering workstation is also discussed. >

PROTEAN: a high-level Petri net tool for the specification and verification of communication protocols

It is suggested that as rule-based system (RBS) technology gains wider acceptance, the need to create and maintain large knowledge bases will assume greater importance. Demonstrating a rule base to be free from error remains one of the obstacles to the adoption of this technology. An approach to RBS verification in which the system is modeled as a Petri net on which error detection is performed is presented. A set of propositions is formulated to locate errors of redundancy, conflict, circularity, and gaps in domain knowledge. Rigorous proofs of these propositions are provided. Difficulties in implementing a Petri net-based verifier and the potential restrictions of the applicability of this approach are discussed. >

Investigating the applicability of Petri nets for rule-based system verification

This dissertation proposes new methodologies for the supervisory control of concurrent systems. The focus of this work is on discrete-event concurrent systems. However, the extension of the discrete-event methods to concurrent systems with continuous dynamics is also approached. Petri nets are a convenient discrete-event representation of concurrent systems, and are used here for the modeling of concurrent systems. 
Several discrete-event supervisory control problems are approached here. First, the enforcement of specifications described as linear inequalities in terms of three Petri net parameters is considered. Then, the decentralized supervisory control problem is considered for specifications described by linear marking inequalities. The decentralized supervision problem is approached in three settings: no communication, unrestricted communication, and restricted communication. Finally, procedures for deadlock prevention and liveness enforcement are presented. Additionally, new results relating deadlock and liveness to the structure of a Petri net are also presented. The main feature of the supervision methods proposed in this dissertation is that they rely on the structure of the Petri net. This structural approach has computational benefits and allows the supervisor design to be independent of the initial state of the system. The methods are given in a general supervision setting, which makes no assumptions on the structure of the Petri nets and allows partial controllability and partial observability to be present. 
This dissertation addresses also the supervisory control problem in the more general framework of hybrid systems, that is, systems involving both discrete-event and continuous dynamics. A two-level approach is proposed. The lower level design is concerned with the development of controllers for the continuous part of the hybrid systems. The higher level design is concerned with the design of a supervisor coordinating the operation of the lower level controllers, according to given discrete-event specifications. At the higher methodologies can then be applied to design the appropriate supervisor. The discrete-event setting here is extended to model some of the hard constraints arising in the supervision of hybrid systems. Extensions of discrete-event methods to this setting are also approached. Finally, the controller design at the lower level is considered in a discrete-time setting. The controller level. 
This dissertation aims to contribute to the automated design of controllers for complex systems. This work is believed to be relevant for applications in a variety of areas, including automated manufacturing, robotics, computer networks, and traffic control.

Methods for the supervisory control of concurrent systems based on petri net abstractions

The authors propose a protocol synthesis method in which both service and protocol specifications are based on a state-transition model. In particular, they present an algorithm for deriving the protocol specification from a given service specification which is described by a set of directly coupled finite state machines (FSMs). These FSMs together regulate the execution sequence of service primitives intended by the service specification. To complement the protocol derivation algorithm for dealing with error-prone communication medium, the authors also devise a transformation procedure to construct an error-recoverable protocol from its error-free version derived from the proposed algorithm. >

http://ieeexplore.ieee.org/iel2/215/626/00017231.pdf

Protocol synthesis in a state-transition model

This paper presents a method for specifying and analysing communication protocols using Numerical Petri Nets (NPNs). These nets are analysed using PROTEAN — a PROTocol Emulation and ANalysis computer aid which incorporates graphics. NPNs and PROTEAN are described and illustrated by the analysis of an Integrated Services Digital Network access protocol. Results of the application of the method to a number of "real world" protocols are reported.

Protocol analysis using numerical Petri nets

This paper is intended to survey the applicability of Petri nets for protocol, as well as for service specification and validation. At the specification level, different classes of nets are introduced, and emphasis is given to the modular specification of a protocol layer. At the validation level, the analysis techniques implemented in the CAD package OGIVE/OVIDE are presented, and are used in order to prove safety and progress properties of a protocol layer. Finally, the specification and validation of the ISO Transport protocol is chosen as a significant example of the proposed design methodology.

B. Algayres

Papers

Petri nets are good for protocols