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Transcript of Jorge Muñoz-Gama Universitat Politècnica de Catalunya (Barcelona, Spain) Algorithms for Process...
Jorge Muñoz-Gama
Universitat Politècnica de Catalunya
(Barcelona, Spain)
Algorithms for Process Conformance and
Process Refinement
Process Conformance and Refinement
2
Outline
9 Sep 2010
Process Mining , Conformance and Refinement
Process Conformance Related Work and Motivation Approach Implementation and Results Extensions
Process Refinement Breaking Concurrencies Supervisory Control Refinement
Future Work and Conclusions
Process Conformance and Refinement
4
Refinement
Process Conformance and Refinement
9 Sep 2010
Petri Net
A B DA C D
Event Log
MDT
ETC Precision
Metric
Conformance
(Precision)
A D
C
B
AC
BD
Refined Model
Locate the inconsistencies
Measure the inconsistencies
More accurate model
Process Conformance and Refinement
5
Conformance Dimensions
9 Sep 2010
Fitness
Precision
Generalization
Structure
How much of the observed behavior is
captured by the model
Minimal structure which clearly reflect the
behavior
Models with minimal behavior to represent
accurately the log
Overly precise models which overfit the log
Process Conformance and Refinement
6
Outline
9 Sep 2010
Process Mining , Conformance and Refinement
Process Conformance Related Work and Motivation Approach Implementation and Results Extensions
Process Refinement Breaking Concurrencies Supervisory Control Refinement
Future Work and Conclusions
Process Conformance and Refinement
7
Related Work
9 Sep 2010
Precision in the literature Most related work Rozinat et al. Information System 33 (2008) Metric for Precision in Petri Nets Computation of Follows and Precedes relations (Always,
Never, Sometimes) of Model and Log.
Measurement based on discrepancies in Sometimes relations Model relations require a model space state exploration
Coverability
Graph
Process Conformance and Refinement
8
Other Approaches and Motivation
9 Sep 2010
Other approaches as language equivalence or bisimilarity are not suitable for Process Conformance The complete models behavior is required
Goals and Requirements Precision Dimension Petri Nets Avoid the complete state space exploration Effort needed to obtain an accurate model Fine-level precision Locate the precision inconsistencies
Process Conformance and Refinement
9
Outline
9 Sep 2010
Process Mining , Conformance and Refinement
Process Conformance Related Work and Motivation Approach Implementation and Results Extensions
Process Refinement Breaking Concurrencies Supervisory Control Refinement
Future Work and Conclusions
Process Conformance and Refinement
10
General Idea: Escaping Edges
9 Sep 2010
ModelBehavior
LogBehavior
ModelBehaviorEscaping
Edges
Process Conformance and Refinement
11
Conformance Route Map
9 Sep 2010
ModelStates
LogStates
Traversal
MDT
Metric
AC
BD
A B DA C D
Petri Net
Event Log
Process Conformance and Refinement
12
Log and Model States
9 Sep 2010
Log Incorporate state information in the log
(Aalst et al. Software and Systems Modeling, 2009) Past, Unlimited and Sequence
Model Markings of the Petri Net
Process Conformance and Refinement
13
Model States and Mapping
9 Sep 2010
Not all the reachable markings (could be infinite)
Only Markings with a Log State mapped on
Log and Model States Mapping i.e., reached marking after replay state prefix
A E
D
C
Bp1 p2 p3
A B Ep4 s1
p1
s2
p2
s3
p3
s4
p4p5
0 1 0 0 1…
0 1 0 0 n
p1 p2 p3 p4 p5
Markings not explored
Process Conformance and Refinement
14
Traversal
9 Sep 2010
Log-guided Traversal of Model Behavior Allowed Tasks :
i.e., actions enabled in that moment
Reflected Tasks : i.e., actions really executed (thus, annotated in the
log)
A E
D
C
Bp1 p2 p3 p4
A E
D
C
Bp1 p2 p3 p4
A B EA C E
<p2>BCD
A B EA C E
BC
Process Conformance and Refinement
15
Traversal (2)
9 Sep 2010
Escaping Edges : i.e., enabled actions not executed Precision discrepancies
A E
D
C
Bp1 p2 p3 p4
A B EA C E
BCD
BC
D
Process Conformance and Refinement
16
Precision Metric
9 Sep 2010
Take into account the Escaping Edges
Between 0 (imprecise) and 1 (precise) More frequent traces, more weight in the metric Independent of Structural dimension Globally precision Localizability
AP
HZ
Q
IA H I ZA P Q Z
Process Conformance and Refinement
17
Minimal Disconformant Traces (MDT)
9 Sep 2010
Localizability of precision inconsistencies
i.e., Minimal traces indicating where the model starts to deviate from the log
Algorithm to compute all MDT using Escaping Edges
Refinement
AnalysisPrecisionMDT
A EA B E
C D P Q
A D
C
B
Refined Petri Net
Process Conformance and Refinement
18
Outline
9 Sep 2010
Process Mining , Conformance and Refinement
Process Conformance Related Work and Motivation Approach Implementation and Results Extensions
Process Refinement Breaking Concurrencies Supervisory Control Refinement
Future Work and Conclusions
Process Conformance and Refinement
19
Implementation
9 Sep 2010
ProM 6 Framework
ETConformance Plug-In
Process Conformance and Refinement
22
Outline
9 Sep 2010
Process Mining , Conformance and Refinement
Process Conformance Related Work and Motivation Approach Implementation and Results Extensions
Process Refinement Breaking Concurrencies Supervisory Control Refinement
Future Work and Conclusions
Process Conformance and Refinement
23
Invisible Tasks
9 Sep 2010
Enabled Tasks? C ? B and C ?A
A
A
C
Bp3
p4
... A C ...
Which Marking? <p4> ? <p3,p4> ?
INDETERMINISM
(Transitions associated with no event)
Process Conformance and Refinement
24
Invisible Tasks (2)
9 Sep 2010
Invisible Coverability Graph
Solutions Union of
Enabled Lazy Invisibles * One path only Shortest
Invisible Path *
<1, ω, 0>
<0, ω, 1>
<1, 0, 0>
<0, 0, 1>
Inv1
Inv3
Inv2
A,B
A,DC
A,C
A
D
B
X
XC
X
*Rozinat et al. Information System 33 (2008)
Process Conformance and Refinement
25
Duplicate Tasks
9 Sep 2010
Which Task? B ? B ?
INDETERMINISM
Solutions e.g. Look-ahead
AB
B
D
C
... A B C ...
(Several Transitions associated with the same event)
Process Conformance and Refinement
26
Variant: States as Markings
9 Sep 2010
States as Prefix
States as Markings
A
B
CA B C
A
B
CA B C
<p1><p2><p3>
C B
p1 p2 p3
2Escaping Edges
NO Escaping Edges
Process Conformance and Refinement
27
Variant: Non fitting models
9 Sep 2010
Symmetric to the Escaping Edges (Ee) Log Escaping Edges (LEe): The points where
the log deviates from the model
Fitness instead of Precision
ModelBehavio
r
LogBehavio
r
ModelBehavio
r
Escaping
Edges
LogEscapingBehavior
Process Conformance and Refinement
28
Outline
9 Sep 2010
Process Mining , Conformance and Refinement
Process Conformance Related Work and Motivation Approach Implementation and Results Extensions
Process Refinement Breaking Concurrencies Supervisory Control Refinement
Future Work and Conclusions
Process Conformance and Refinement
29
Future Work: Refinement
9 Sep 2010
Refinement can be performed by a Domain Expert
Refinement
Breaking Concurrencie
s
Supervisory Control
AC
BD
Petri Net
Refined Petri Net
A D
C
BEvent Log
A EA B E
MDT
A EA B E
B H J G
Process Conformance and Refinement
30
Many causes for precision inconsistencies
Common one is Concurrency Concurrency in the model allowing several
possibilities But not in the log
Idea is to break the concurrency introducing a new place
We need concurrency relations of the Petri net, the log, and check the results of the new model
Breaking Concurrencies
9 Sep 2010
Process Conformance and Refinement
31
Concurrency: it exists a reachable marking that enables both transitions, and firing one does not disable the other.
Problematic for large nets Structural Concurrency
Best effort overapproximation for general Petri Nets Exact for live and bounded Free Choice systems Polynomial Algorithm
Kovalyov and Esparza , Proc. Intl. Workshop on Discrete Event Sytems, 1996
Breaking Concurrencies: Petri net
9 Sep 2010
A D
C
B
Process Conformance and Refinement
32
Not concurrencies but the absence of them Firing Causality Matrix:
Firing Causality:
Breaking Concurrencies: Log
9 Sep 2010
A B C D
0
Process Conformance and Refinement
33
Break the model concurrency with a place
Breaking Concurrencies
9 Sep 2010
A B C DA D
C
B
Process Conformance and Refinement
34
Supervisory Control
9 Sep 2010
Supervisory Control in Process Mining Santos et al. Supervisory Control Service (2010)
Supervisor
Model
MDT MDT Abstraction
Refined Model
Process Conformance and Refinement
35
Conclusions and Future Work
9 Sep 2010
New technique for precision between Petri nets and Log.
Avoids models state space exploration.
MDT, indicating the points where the model starts to deviates from the log.
Approach implemented as plug-in of ProM 6.
Breaking concurrencies to improve the precision.
Supervisory Control for precision refinement.