Lezione 14 Model Transformations for BP Analysis and Execution

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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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( 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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( 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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= 1

= 2

= 0

= 0

missing tokens

remaining tokens

consumed tokens

produced tokens

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= 2

= 4

= 0

= 0

missing tokens

remaining tokens

consumed tokens

produced tokens

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= 3

= 5

= 0

= 0

missing tokens

remaining tokens

consumed tokens

produced tokens

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= 5

= 6

= 0

= 0

missing tokens

remaining tokens

consumed tokens

produced tokens

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= 6

= 7

= 0

= 0

missing tokens

remaining tokens

consumed tokens

produced tokens

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= 7

= 7

= 0

= 0

missing tokens

remaining tokens

consumed tokens

produced tokens

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= 9

= 9

= 0

= 0

missing tokens

remaining tokens

consumed tokens

produced tokens

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= 9

= 9

= 0

= 0

missing tokens

remaining tokens

consumed tokens

produced tokens

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= 0

= 1

= 0

= 0

missing tokens

remaining tokens

consumed tokens

produced tokens

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= 1

= 2

= 0

= 0

missing tokens

remaining tokens

consumed tokens

produced tokens

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= 2

= 4

= 1

= 0

missing tokens

remaining tokens

consumed tokens

produced tokens

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= 3

= 5

= 1

= 0

missing tokens

remaining tokens

consumed tokens

produced tokens

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= 4

= 6

= 1

= 0

missing tokens

remaining tokens

consumed tokens

produced tokens

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= 6

= 7

= 1

= 0

missing tokens

remaining tokens

consumed tokens

produced tokens

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= 7

= 8

= 1

= 0

missing tokens

remaining tokens

consumed tokens

produced tokens

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= 8

= 8

= 1

= 1

missing tokens

remaining tokens

consumed tokens

produced tokens

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= 8

= 8

= 1

= 1

missing tokens

remaining tokens

consumed tokens

produced tokens

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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

Lezione 14 Model Transformations for BP Analysis and Execution

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