Analysis of workflows: Verification, validation, and performance analysis.

1
Analysis of workflows Verification, validation,
and performance analysis.
Wil van der Aalst

• Eindhoven University of Technology
• Faculty of Technology Management
• Department of Information and Technology
• P.O. Box 513
• 5600 MB Eindhoven
• The Netherlands
• w.m.p.v.d.aalst_at_tm.tue.nl

2
Design-time and run-time questions
Run-time
Design-time

• verificationvalidationperformance analysis

• process mining

3
Techniques to analyze workflows (design-time)

• Validation is concerned with the relation between
  the model and reality.
• Verification is typically used to answer
  qualitative questions
• Is there a deadlock possible?
• It is possible to successfully handle a specific
  case?
• Will all cases terminate eventually?
• It is possible to execute two tasks in any order?
• Performance analysis is typically used to answer
  quantitative questions
• How many cases can be handled in one hour?
• What is the average flow time?
• How many extra resources are required?
• How many cases are handled within 2 days?

4
Verification analysis techniques can be used to
avoid logical errors.
c3
check_policy
send_letter
c4
c1
c5
c2
ready
start
register
pay_damage
check_damage
c6
Is this a correct workflow? If not, how to
correct it?
5
It this process correct?
6

7

8
Petri-nets a solver-independent medium
9

10
Reachability analysis
11

• Reachability graph
• Each node corresponds to a reachable state.
• Done by a computer.
• A computer can cope with reachability graphs with
  millions of nodes.

The traffic lights are safe!
12

13

14

15
Exercise construct reachability graph
c3
check_policy
send_letter
c4
c1
c5
c2
ready
start
register
pay_damage
check_damage
c6
16