Post on 14-Jan-2022
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Ingegneria dei Processi Aziendali
Modulo 1 - Servizi Web
Unità didattica 1 – Protocolli Web
Ernesto Damiani
Università di Milano
Lezione 14 – Model Transformations for BP Analysis and Execution
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Business Process Management (BPM)
Collection of methods and techniques to
design, analyze, execute and monitor business
operations involving humans, software,
information and physical artifacts using
process models.
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OK, so what is a process model?
Collection of inter-dependent activities whose collective performance is intended to achieve a goal such as delivering a product or a service.
E,g. order-to-cash, procure-to-pay, issue-to-resolution
Check
Completeness
Obtain
Additional
Information
Check Credit
History
Check Income
Source(s)
Credit Card
Application
Assess
Application
Make Credit
Offer
Notify
Rejection
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Process models serve many purposes…
Process
Documentation
Workflow
Management
Enterprise
Architecture Document
Management
Knowledge
Management
Process
Improvement
Process Cost
Analysis / Simulation Enterprise
Systems
Compliance /
Risk Management
Software
Evaluation/
Selection
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… they have many faces
Process
Implementation
Process
Analysis & Design
Process
Enactment &
Monitoring
Process
Evaluation
“TO BE”
Process Models
Ex
ec
uta
ble
Pro
ce
ss
Mo
de
ls
Me
as
ure
s f
or
Imp
rov
em
en
t
Process
Metrics
Organizational
Analysis
Ta
rge
t V
alu
es
“AS IS”
Process
Models
Abstract Models
EPC, BPMN
Communication,
simulation, activity-
based costing…
Detailed Models
BPEL, State Machines…
Data types, conditions, data
mappings, fault handling…
Integration, testing,
deployment…
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…and can be seen from many perspectives
Control-flow
Data
Resource
Operational
Sound design
Dialog premix FX premix
Music designComposer
Sound Designer
Editor
V
V
Temp picture cut
Temp picture cut
V
V
V
V
Temp music output
Temp sound output
Effect cues Dialog cues Music cues
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Many in one, or one in many?
“The thing can be many in one sense, but
also can be one in another sense.”
Imam Ghazali
Revival of Religious Sciences
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Process Modelling: Dealing with Multiplicity
Multiple modelling languages (meta-models)
Multiple modelling viewpoints
• Control-flow view vs. data view
• Public views (protocols) vs. private views
Multiple abstraction levels
• High-level: tasks, performance metrics...
• Low-level: data transformations, application bindings...
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Process Modelling Notations
• Business Process Modelling Notation
(BPMN)
• Event-driven Process Chains (EPC)
• Business Process Execution Language
(BPEL)
• State machines and variants (e.g. IBM
Business State Machine, WWF)
• Petri nets (and variants, e.g. YAWL)
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Model transformations
BPMN-to-BPEL
• Purpose: Transform models produced by analysts into models for developers (and vice-versa)
• Commonly supported in commercial tool, but in a limited manner
BPEL-to-Petri nets
• For analysis & verification
BPMN-to-Petri nets
• For analysis & verification (e.g. deadlock-freeness)
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BPMN from 10 000 miles…
Event Task Flow Gateway
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BPMN: A more detailed view
Start EventIntermediate
Message EventIntermediate Timer Event
Task Parallel Fork Gateway
Parallel Join Gateway
End Terminate EventEnd Event
Flow Event-based Decision Gateway
receive
Merge Gateway
Data-based Decision Gateway
c
~c
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Quick BPMN example
Check stock
availability
Reject order
Confirm order
Send invoice
Ship goods
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BPEL from 10 000 miles
Basic activities: <assign>, <invoke>,
<receive>
Sequential flow: <sequence>, <while>,
<switch>
Block-structured parallel flow: <flow>
Graph-oriented (parallel) flow: <link> **
Event-action rules: <onEvent> **
Other constructs not relevant to this talk…
** Only partially supported by some tools
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A quick BPEL example
<sequence>
<invoke “check stock availability” …/>
<switch (…) …/>
<case “reject”> <invoke “order rejection” …/> </case>
<otherwise>
<sequence>
<invoke “order acceptance” … />
<flow> <invoke “invoicing” … />
<invoke “ship goods” … />
</flow>
</sequence> </otherwise> </switch> </sequence>
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BPMN-to-BPEL: Some monsters!
Bounded multiple-
instance task (D)Unstructured loop
LivelockUnbounded multiple-
instance tasks (C)
A B C D
A B C D
A D
A
B
C
D
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BPMN-to-BPEL (from 10 000 miles)
Repeat until reduction to a single node
1. Identify a structured & quasi-structured SESE region
Fold into a BPEL structured activity
2. Identify irreducible SESE regions without parallelism
Apply GotoWhile transformations, repeat from 1
3. Identify acyclic fragments with concurrency
Fold into a BPEL activity with control links
4. Identify minimal unstructured components
BPEL event handlers
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BPMN-BPEL: Structured Components
( a ) SEQUENCE-component
( b ) FLOW-component
<sequence> <invoke name="t1"/> <receive name="e1"/> . . . <invoke name="tn"/></sequence>
tc
<flow> <invoke name="t1"/> <wait name="e2"/> . . . <invoke name="tn"/></flow>
tc
t1
e1
tn
t1
tn
e2
C
C
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BPMN-BPEL: Structured Components
( e ) WHILE-component
( f ) REPEAT-component
<while condition="c1"> <invoke name="t1"/></while>
tc
<sequence> <invoke name="t1"/> <while condition="c1"> <invoke name="t1"/> </while></sequence>
tc
c1
~c1
t1
C
c1
~c1t1
C
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BPMN-BPEL: Structured Components
( c ) SWITCH-component
( d ) PICK-component
<switch> <case condition="c1"> <invoke name="t1"/> </case> <case condition="c2"> <receive name="e1"/> </case> . . . <otherwise> <empty/> </otherwise></switch>
tc
tc
<pick> <onMessage name="e1"/> <invoke name="t1"/> </onMessage> <onAlarm name="e2"> <empty/> </onAlarm> . . . <onMessage name="tr"> <invoke name="tn"/> </onMessage></pick>
tn
t1
tr(receive)
e1
e2
C
t1
c2
default
c1
e1
C
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Example: Only Structured Components
Check stock
availability
Reject order
Confirm order
Send invoice
Ship goods
Flow-component
Switch-component
Sequence-component
Sequence-component
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BPMN-to-BPEL: Acyclic component
T1
T2
T3
T4
T1 T3
T2 T4
Flow-component
AND
BPMN BPEL
Proposition: Every acyclic BPMN component
with a single entry point and a single exit
point that is 1-safe and sound can be
mapped to a BPEL Flow with links
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Example Structured+Acyclic Components
a2
C1
f2
f3
m4
UBL
receive EDI 856
(ASN)
receive EDI 810
(Invoice)
receive
despatch-advice
receive invoice
EDI
send
payment-request
send
fulfillment-notice
a1
a4
a3
a5
a6
d1
m5
j6
tc1 send
fulfillment-notice
a6C2
tc2
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Minimizing the use of control links
a1
a3
a2
a5
a4
a6
a7
a8
fc
jc
g2
g1
g3
g4
g5
t1
a5
a7
t2
t3
g4
jc
fc
[a3, a4]
[a1, a2]
[a6, a8]
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For the rest…
Identify a minimal SESE region that is neither structured nor acyclic
For each action in the component, retrieve:
• All actions that immediately precede it
• All actions that immediately follow it
For each action, code the following behaviour using event-action rules:
• Wait for a suitable combination of predecessors to complete
• Perform action
• Notify completion to all successors
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BPEL-to-Petri net Application to Conformance Checking
Services
Services abstract
BPEL
process
Petri net
model
SOAP
Messages
Event Log
Services
Monitoring /
Correlation
Conformance?
Conformance
Checking!
Translation
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From BPEL to WF-nets
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Petri net-based Conformance Checking
Objectives:
• quantitatively measure conformance
• locate deviations
Conformance?
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Conformance Checking – Fitness
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Conformance Checking – Fitness
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Measuring fitness: Log replay analysis
missing tokens
remaining tokens = 0
= 1
consumed tokens
produced tokens = 0
= 0
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Measuring fitness: Log replay analysis
= 1
= 2
= 0
= 0
missing tokens
remaining tokens
consumed tokens
produced tokens
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Measuring fitness: Log replay analysis
= 2
= 4
= 0
= 0
missing tokens
remaining tokens
consumed tokens
produced tokens
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Measuring fitness: Log replay analysis
= 3
= 5
= 0
= 0
missing tokens
remaining tokens
consumed tokens
produced tokens
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Measuring fitness: Log replay analysis
= 5
= 6
= 0
= 0
missing tokens
remaining tokens
consumed tokens
produced tokens
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Measuring fitness: Log replay analysis
= 6
= 7
= 0
= 0
missing tokens
remaining tokens
consumed tokens
produced tokens
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Measuring fitness: Log replay analysis
= 7
= 7
= 0
= 0
missing tokens
remaining tokens
consumed tokens
produced tokens
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Measuring fitness: Log replay analysis
= 9
= 9
= 0
= 0
missing tokens
remaining tokens
consumed tokens
produced tokens
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Measuring fitness: Log replay analysis
= 9
= 9
= 0
= 0
missing tokens
remaining tokens
consumed tokens
produced tokens
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Measuring fitness: Log replay analysis
= 0
= 1
= 0
= 0
missing tokens
remaining tokens
consumed tokens
produced tokens
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Measuring fitness: Log replay analysis
= 1
= 2
= 0
= 0
missing tokens
remaining tokens
consumed tokens
produced tokens
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Measuring fitness: Log replay analysis
= 2
= 4
= 1
= 0
missing tokens
remaining tokens
consumed tokens
produced tokens
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Measuring fitness: Log replay analysis
= 3
= 5
= 1
= 0
missing tokens
remaining tokens
consumed tokens
produced tokens
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Measuring fitness: Log replay analysis
= 4
= 6
= 1
= 0
missing tokens
remaining tokens
consumed tokens
produced tokens
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Measuring fitness: Log replay analysis
= 6
= 7
= 1
= 0
missing tokens
remaining tokens
consumed tokens
produced tokens
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Measuring fitness: Log replay analysis
= 7
= 8
= 1
= 0
missing tokens
remaining tokens
consumed tokens
produced tokens
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Measuring fitness: Log replay analysis
= 8
= 8
= 1
= 1
missing tokens
remaining tokens
consumed tokens
produced tokens
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Measuring fitness: Log replay analysis
= 8
= 8
= 1
= 1
missing tokens
remaining tokens
consumed tokens
produced tokens
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Measuring fitness: Log replay analysis
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Measuring fitness: Log replay analysis
f = 1.0 f ≈ 0.540 f ≈ 0.955
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Conformance Checking - Appropriateness
100 % fitness
but not sufficiently
specific from
behavioral point of view.
100 % fitness
but not represented in
structurally suitable way.
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Ongoing work
Reversible BPMN ↔ BPEL transformation
Two-way transformation: BPEL ↔ FSM
• Application to automated service composition
• BPEL FSM not too difficult
• FSM BPEL more exciting, e.g.
A
B
B
A
A
BFINE