2 research outputs found
Petri net modelling of a communications protocol
The Petri net is a formal modelling tool applicable to
distributed systems and communication protocols. Two
methods of analysis are applied to formal models of the
"Alternating Bit Protocol".
(i) A timed Petri net model is simulated
to measure protocol performance.
(ii) A modular numeric Petri net model is validated
by reachability analysis.
The simulation and validation tools are programmed in
(i) "C" language and (ii) Prolog. A specification language
"Needle" is developed. It describes the model system as a
hierarchy of modular state transition networks. The model is
searched for all possible event sequences, and the result
displayed as a reachability tree. The specification language
is capable of describing models which execute backwards in
simulation time. The modular numeric Petri net is the basis
of a powerful computer architecture, capable of parsing its
own specification language to build complex models.
Attention is drawn to the similarities between Petri net
theory and quantum mechanics
Modelling and analysis of parallel information systems.
This thesis presents an investigation of modelling and analysis of parallel information systems. The research was motivated by the recent developments in networks and powerful, low-cost, desk top multiprocessors. An integrated approach for the construction of parallel information systems was developed which focussed on modelling, verification and simulation of such systems. The thesis demonstrates how Petri nets can be used for the modelling and analysis of entity life histories and parallel information systems, place transition nets for the modelling and analysis of entity life histories and coloured Petri nets for the modelling and analysis of complex parallel information systems. These tools were integrated into a comprehensive framework which allowed for the modelling and analysis of complex parallel information systems and the framework was tested using a comprehensive case study. The thesis concludes that Petri nets are an ideal tool for the modelling and analysis of complex parallel systems. Verification is possible with deadlocks and similar properties being easily identified. Further the transformation rules proved to be beneficial to the process of moving from one model to another. Finally simulation of parallel behaviour was possible because the underlying models captured the notion of parallelism