Information Technology Reference
In-Depth Information
Table 2.1
A Comparison of Basic Petri Nets and Colored Petri Nets
Colored Petri nets
(Definition 2.6)
Petri nets
(Definition 2.1)
Place
Type of tokens
Color set (specifying the
type of tokens that
may reside in a place)
N/A (tokens in all
places are
nondistinguishable)
Initial marking
of a place
A multiset of token
colors
A nonnegative integer
Transition
Firing
conditions
When its guard function
(Boolean expression
containing some
variables) evaluates
to true
N/A (a transition can
fire when its input
places have
sufficient tokens)
Arc
Tokens to
consume and
produce
Arc expression (containing
some variables)
evaluates to a multiset
of token colors
Each arc has a weight
that is a nonnegative
integer
To help understand the enhancement of colored Petri nets over
prior-defined Petri nets, Table 2.1 gives the comparison results for them.
In Chapters 3 and 4 we use colored Petri nets to model different data
types and messages used by service workflows. Other types of Petri net
extensions, such as hierarchical Petri nets, timed Petri nets and stochastic
Petri nets, are also relevant in the analysis of workflow and service
composition. In this topic we do not specifically use them and readers are
referred to References [83-85] for various Petri net extensions.
