An Effective Approach to Model Workflow Process
HaiLan Pan Jian Chen
School of Computer and Information School of Computer and Information
Shanghai Second Polytechnic University Shanghai Second Polytechnic University
Shanghai 201209 China Shanghai 201209 China
panhailan@sspu.cn chenjian@sspu.cn
Abstract—The most important thing to workflow management is
modeling business processes. It can ensure the correctness after
model is put to use only when efficient modeling technology is
used to build complex business processes. On the one hand the
readability of model represented can be improved on the other
hand it is convenient to the model performance analysis. This
paper points out that the strict semantic of Petri net is conducive
to time performance analysis after modeling the process, so Petri
technology is selected to define WF-net and four equivalent
formulas which are sequential, parallel, selection and circulation.
Then the article analyzes process instances in buying a car, and
the Petri net model is established. Finally the paper analyzes its
time performance to prove the rationality and superiority of
modeling based on Petri net technology.
Keywords-E-Commerce; WF-net; Petri net; Routing structure;
Work Flow Model; Time performance analysis
I. INTRODUCTION
Until now, technology of workflow has been used in
many fields and workflow management has brought many
great changes for enterprises’ processes management. But
such as handling abnormal, monitoring processes,
reconstructing process and so on, and all these Technical
difficulties and key points in workflow technology are still
need to be solved and improved, because the establishment of
workflow model is related to those. Petri net defined strictly
and it has the standard model semantic so it is a kind of the
mathematical model and it can build a good model definition.
The enterprise business processes can be handled by computer
only if it can be represented abstractly by Workflow model.
But model performance analysis and evaluation are most
important for enterprises’ processes which decided whether
the model is successful, so Petri net is the best selection.
Workflow response time is one of the most important
performance parameters of the workflow management system,
and it is an important indicator for measuring advantages and
disadvantages of the process. Markov chain analysis process
is the traditional time performance analysis which is too
complicated and its time complexity is index level, so its
practice is difficult [1]. Using fully Petri nets technology can
make formalization definition and realize time performance
analysis, and Workflow-net (WF-net) model combined with
knowledge of probability theory can reduce the time
complexity.
II. WF-
NET MODEL AND ITS PERFORMANCE EQUIVALENT
FORMULA
The performance analysis of WF-net model based on
Petri nets has greatly increased complexity of the time
performance analysis, so the related concepts of will be
introduced at first.
A. WF-net model based on Petri nets
If Place set’s abbreviation is P, Transition set’s
abbreviation is T, and abbreviation of flow relations is F, then
a triple formula PN = (P, T, F) can represent Petri nets, set of
arcs can be said by
()()
PT T P××*
. If in Petri nets |P|
represents the total number of Place, the abbreviation of state
of Petri net is
M
, then in each Place tokens are composed of
|P| dimension vector, and it can be showed by state
M
[2]
.
If state
0M
is defined as the original of workflow, then the
source Place
i must only has one Token whose quantity is
zero in another Place. Assuming that the expression(PN,
0M )
shows Petri nets’ initial state, and the following three
conditions can be realized, WF-net is equals with Petri nets
(PN,
0M ).
a) There is a source Place
i
which is satisfied
i
=
;
b) There is a output Place
o which is satisfied
o
=
;
c) PN is strongly connected only if
*{},*{}toti==
,
the Place
i
and
o
is connected and Transition
t
is
added to PN.
(PN,
0M ) is rational only if it satisfied three conditions in
the following.
a) each original state
0M can reach state
M
, and state
M
to end state Me is an implemented sequence
realization;
b) State
0M can reach State Me which is the sole end
state, and in output Place
o
it only includes one
Token.
c) (PN,
0M ) has no endless Transition.
B. Four model routing structures
Any workflow execution way determines the life cycle of
the case which is described by the related processes, and those
processes point out what tasks need to be carried out and are
execute in what order. Workflow processes are represented by
routings which includes four kinds of basic structures:
sequence, parallel, selection and circulation. Combining with
these four structures can describe all structures of workflow
case. Fig. 1 shows four kinds of control structures based on
Petri nets, and implementation of parallel process combines
AND-split and AND-join, implementation of choice process
combines OR-split and OR-join, symbol " Θ " stands for
Token, symbol "Ϥ" stands for Place, symbol "ϭ" stands for
Transition [3].
2014 Second International Conference on Enterprise Systems
978-1-4799-5554-1/14 $31.00 © 2014 IEEE
DOI 10.1109/ES.2014.64
299
2014 Second International Conference on Enterprise Systems
978-1-4799-5554-1/14 $31.00 © 2014 IEEE
DOI 10.1109/ES.2014.64
301
2014 Second International Conference on Enterprise Systems
978-1-4799-5554-1/14 $31.00 © 2014 IEEE
DOI 10.1109/ES.2014.64
300