| Summary: | 碩士 === 國立臺灣大學 === 電機工程學系 === 85 === Petri nets, a useful model for concurrent systems, lack the
notion of time which is critical in modeling real-time systems.
Thus, Petri nets, in general, are not appropriate for modeling
systems on which timing constraints are imposed. Several timed
versions of Petri nets have been proposed in theliterature,
incorporating timing information into the Petri net model either
implicitly or explicitly. Among such extended Petri nets,
clocked Petri nets associate each transition with a set of
clockconstraints and/or clock reset operations.After we
associate timing information with the transitions of thePetri
net we can use this enhanced model to effectively model real-
time systems. However,since a system's configuration must now
include timing information, both the state space and the system
complexity increase significantly.To reduce the complexity,
weuse the concept of Stubborn set introduced by Antti Valmari.
The intuition behind stubborn sets is simply that in each of the
reachable states, only portion of the next states will be
explored,resulting in a reduced state space. Aside from the
above analytical aspect of clocked Petri nets,in this thesis we
also implement a Time-Warp distributedsimulator on a distributed
shared memory system for simple timedPetri nets. Our empirical
results reveal how the "partition" issue affects the performance
of our simulation.
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