diagnosis of open workflow nets
DESCRIPTION
Workshop presentation given by Niels Lohmann on August 16, 2007 in Eindhoven, The Netherlands at the Berlin-Eindhoven Service Technology Colloquium 2007 (B.E.S.T. 2007).TRANSCRIPT
Niels Lohmannwww.informatik.hu-berlin.de/~nlohmann
Diagnosis of Open Workflow NetsDiagnosis of Open Workflow Nets
B.E.S.T MeetingAugust 16, 2007
Diagnosis of O
pen Workflow
Nets
2
Controllability
! Definition: existence of a partner s.t. composition is weakly terminating
! Can be constructively decided using the algorithm implemented in the tool Fiona
! Today: acyclic nets
Diagnosis of O
pen Workflow
Nets
3
Interaction Graph
x
b
a
y
p1
p3
p4
p2
Diagnosis of O
pen Workflow
Nets
3
Interaction Graph
x
b
a
y
p1
p3
p4
p2
[p1] (TR)
transientstate
Diagnosis of O
pen Workflow
Nets
3
Interaction Graph
x
b
a
y
p1
p3
p4
p2
[p1] (TR)[p3, a] (eDL)
externaldeadlock
transientstate
Diagnosis of O
pen Workflow
Nets
3
Interaction Graph
x
b
a
y
p1
p3
p4
p2
[p1] (TR)[p3, a] (eDL)
?a
externaldeadlock
transientstate
Diagnosis of O
pen Workflow
Nets
3
Interaction Graph
x
b
a
y
p1
p3
p4
p2
[p1] (TR)[p3, a] (eDL)
[p3] (eDL)
?a
externaldeadlock
transientstate
Diagnosis of O
pen Workflow
Nets
3
Interaction Graph
x
b
a
y
p1
p3
p4
p2
[p1] (TR)[p3, a] (eDL)
[p3] (eDL)
[p3, y] (TR)[p4] (FS)
?a
!y
externaldeadlock
transientstate
finalstate
Diagnosis of O
pen Workflow
Nets
3
Interaction Graph
x
b
a
y
p1
p3
p4
p2
[p1] (TR)[p3, a] (eDL)
[p1, x] (TR)
[p3, a, x] (eDL)
[p2] (TR)[p4, b] (eDL)
[p3] (eDL)
[p3, y] (TR)[p4] (FS)
!x ?a
!y
externaldeadlock
transientstate
finalstate
Diagnosis of O
pen Workflow
Nets
3
Interaction Graph
x
b
a
y
p1
p3
p4
p2
[p1] (TR)[p3, a] (eDL)
[p1, x] (TR)
[p3, a, x] (eDL)
[p2] (TR)[p4, b] (eDL)
[p3] (eDL)
[p3, y] (TR)[p4] (FS)
[p3, x] (eDL)
!x
?a
?a
!y
externaldeadlock
transientstate
finalstate
Diagnosis of O
pen Workflow
Nets
3
Interaction Graph
x
b
a
y
p1
p3
p4
p2
[p1] (TR)[p3, a] (eDL)
[p1, x] (TR)
[p3, a, x] (eDL)
[p2] (TR)[p4, b] (eDL)
[p3] (eDL)
[p3, y] (TR)[p4] (FS)
[p3, x] (eDL)
[p3, x, y] (TR)[p4, x] (iDL)
!x
?a
!y
?a
!y
externaldeadlock
transientstate
finalstate
internaldeadlock
Diagnosis of O
pen Workflow
Nets
4
Interaction Graph (cont.)
x
b
a
y
p1
p3
p4
p2
blue rooted subgraph:net is controllable!
Diagnosis of O
pen Workflow
Nets
4
Interaction Graph (cont.)
x
b
a
y
p1
p3
p4
p2
a
y
x
b
Diagnosis of O
pen Workflow
Nets
5
Uncontrollable Nets
x y
p1
p3
p4
p2
x
b
a
p1
p3
p4
p2
Guess the net’s decision!“non-local choice”
Net can deadlock in [p3].
Diagnosis of O
pen Workflow
Nets
6
Interaction Graphs
What is the problem?
Diagnosis of O
pen Workflow
Nets
7
More Colors = Better
Diagnosis of O
pen Workflow
Nets
7
More Colors = Better
Diagnosis of O
pen Workflow
Nets
7
More Colors = Better
blue node:AF final state
Diagnosis of O
pen Workflow
Nets
7
More Colors = Better
blue node:AF final state
red node:AF deadlock
Diagnosis of O
pen Workflow
Nets
7
More Colors = Better
blue node:AF final state
red node:AF deadlock
yellow node:be careful!
Diagnosis of O
pen Workflow
Nets
7
More Colors = Better
blue node:AF final state
red node:AF deadlock
yellow node:be careful!
green node: nothingbad happened (yet)
Diagnosis of O
pen Workflow
Nets
7
More Colors = Better
blue node:AF final state
red node:AF deadlock
yellow node:be careful!
green node: nothingbad happened (yet)
Diagnosis of O
pen Workflow
Nets
7
More Colors = Better
blue node:AF final state
red node:AF deadlock
yellow node:be careful!
green node: nothingbad happened (yet)
trace to problem states
Diagnosis of O
pen Workflow
Nets
8
Goals of my Thesis
1. Diagnosis: Why is a net uncontrollable?“non-local choice between [p2,p3] and [p1,p4]”
Diagnosis of O
pen Workflow
Nets
8
Goals of my Thesis
1. Diagnosis: Why is a net uncontrollable?“non-local choice between [p2,p3] and [p1,p4]”
2. Error location: Where is the problem?“un-communicated decision between t1 and t2”
Diagnosis of O
pen Workflow
Nets
8
Goals of my Thesis
1. Diagnosis: Why is a net uncontrollable?“non-local choice between [p2,p3] and [p1,p4]”
2. Error location: Where is the problem?“un-communicated decision between t1 and t2”
3. Correction: What to change?“t1 must send a message”
Diagnosis of O
pen Workflow
Nets
8
Goals of my Thesis
1. Diagnosis: Why is a net uncontrollable?“non-local choice between [p2,p3] and [p1,p4]”
2. Error location: Where is the problem?“un-communicated decision between t1 and t2”
3. Correction: What to change?“t1 must send a message”
4. Optimization: Can it be done with less messages?“message x sent by t3 is not necessary”
Diagnosis of O
pen Workflow
Nets
9
Goals of my Thesis (cont.)
Variations of the diagnosis setting:! Structure:
! Cyclic nets:new problems: livelocks, unbounded channels
! Composition of several nets:new question: responsibility for deadlocks
! Property:! Distributed controllability:
stronger criterion! Controllability under constraints:
di!erent/fewer final states
Diagnosis of O
pen Workflow
Nets
10
Questions?
DIAGNOSISOF
OPENWORKFLOW
NETS