Configurable Declare: Designing Customizable Flexible Models

Dennis Schunselaar

Fabrizio Maggi

Natalia Sidorova

Wil van der Aalst

http://www.win.tue.nl/coselog/

Procedural versus Declarative

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Procedural versus Declarative

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Procedural Process Models

• Mainstream notations: BPMN, EPCs, ULM Ads, etc.• Nothing is possible unless explicitly triggered.• Removing model elements yields "less" behavior.• Procedural models become complex when there are

many alternative paths (flexibility implies complexity).

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register request

add extra insurance

check drivers licence

initiate check-in

start

selectcar

charge credit card

initiate check-in

end

register request

add extra insurance

check drivers licence

start

charge credit card

initiate check-in

end

Remark on Petri Nets

• Petri nets are typically classified as procedural, but adding a place can only remove behavior.

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book car

c

add extra insurance

d change booking

e

confirm initiate check-in

j

check driver’s license

k

charge credit card

i

select car

g

supply car

a

b

skip extrainsurance

f

h

add extra insurance

skip extra insurance

l

book car

c

add extra insurance

d change booking

e

confirm initiate check-in

j

check driver’s license

k

charge credit card

i

select car

g

supply car

in

a

b

skip extrainsurance

f

h

add extra insurance

skip extra insurance

l

c5

c6

c7

c9

c10

c11

book car

c

add extra insurance

d change booking

e

confirm initiate check-in

j

check driver’s license

k

charge credit card

i

select car

g

supply car

in

a

b

skip extrainsurance

f

h

add extra insurance

skip extra insurance

l

out

c1 c2

c3

c4

c5

c6

c7

c8

c9

c10

c11

The Declare language

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b

c

a e

non co-existence: activities b and c cannot happen both

response: every occurrence of c should be eventually followed by h

g

h

precedence: every occurrence of c needs to be preceded by a

response

non co-existence

precedence

book car

add extra insurance early

confirm

skip extraInsurance early

add extra insurance late

skip extra insurance late

Basic idea

A B

LTL semantics

Example: "existence response"

• OK:• [ ]• [A,B,C,D,E]• [A,A,A,C,D,E,B,B,B]• [B,B,A,A,C,D,E]• [B,C,D,E]

• NOK• [A]• [A,A,C,D,E]

A B

Example: "response"

• OK:• [ ]• [A,B,C,D,E]• [A,A,A,B,C,D,E]• [B,B,A,A,B,C,D,E]• [B,C,D,E]

• NOK• [A]• [B,B,B,B,A,A]

A B

Example: "precedence"

• OK:• [ ]• [A,B,C,D,E]• [A,A,A,C,D,E,B,B,B]• [A,A,C,D,E]

• NOK• [B]• [B,A,C,D,E]

A B

Non-Configurable versus Configurable models

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Two variants of the same process …

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Configurable Process Model

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Variants of the same process

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aa bb

dd

ee

gg hh

cc

ff

aa bb

dd

gg hh

ff

aa

dd

ee

gg hh

cc

ff

Some quotes from Michelangelo• “Every block of stone has a statue

inside it and it is the task of the sculptor to discover it.”

• “I saw the angel in the marble and carved until I set him free.”

• “Carving is easy, you just go down to the skin and stop.”

Michelangelo's David

Positioning of Configuration

Life is about making choices …

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Configurable Process Models

Purchase order created

Service is accepted

Goods receipt posted

Invoice received

V

V

Process Invoice

XOR

Goods receipts

to be settled automatically

Evaluated Receipt

Settlement (ERS)

Invoicetransmitted for vendor’s

records

Material is released

Invoice postedand blocked for release

Invoicing plans require

settlement

Invoicing Plan Settlement

V

Release Invoice

manually

Payment mustbe effectes

V

GUIDELINEERS = ON, if - long term

contract- goods and

conditions are specified

REQUIRED:IPS = ON

Þ ERS = ON

Consignment/pipeline

liability is created

Consignment/pipeline

liabilities are to be settled

Consignment/ Pipeline

Settlement

V

XOR

V

Consignment/pipeline

settlement document

transmitted

XOR

XOR

Invoice postedand not

blocked for release

Release Invoice

automatically

Purchase order created

Service is accepted

Goods receipt posted

Invoice received

V

V

Process Invoice

Material is released

Invoice postedand blocked for release

Release Invoice

manually

Payment mustbe effectes

V

XOR

XOR

Invoice postedand not

blocked for release

Release Invoice

automatically

Blocking HidingConfiguration

C-EPC

C-Petri Net

C-YAWL

C-BPEL

EPC

Petri Net

YAWL

BPEL

a b

cd e

f g

h i

j

k mn

o p

l

a b

ce

g

i

mn

o p

l

C-LTS

LTS

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a

c

e

i

g

i

Configuration Techniques

b

p

d

f

h

l

m

n

j

k

l

blockblock

o

• Blocking(removing an option)

• Hiding(skipping activities)

a b

c

d e

f g

h i

j

k m

n

o p

l

τ

hidehide

hideBlocking and hiding are the essential concepts of configuration.

“Every block of stone has a statue inside it and it is the task of the sculptor to discover it.”

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Configurable Declare models

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procedural declarative

non-

confi

gurable

confi

gurable

• Subset of activities is "hideable".

• Subset of constraints is "omissible".

• There may be dependencies between the different configuration decisions (meta-constraints)

Configurable Declare

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"hideable" activity "omissible" constraint

meta constraints are not shown graphically

Step 1: Hide subset of hideable activities

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note the implicitly derived constraints

Step 2: select valid subset of constraints (remove some of the omissible constraints)

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Implicit Constraints Made Explicit When Hiding

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Details (see paper)

• Not always possible to have language equivalence: use the closest constraint stronger/weaker than the implicit inexpressible constraint.

• Implicit constraints that are made explicit because of hiding may be omissible.

• Hiding is done iteratively.• Meta constraints need to be updated when hiding

activities, in fact completely new meta constraints may be introduced.

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Example from CoSeLoG project

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Municipality A

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Municipality B

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Municipality C

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Conclusion

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procedural declarative

non-

confi

gurable

confi

gurable

• Configurable Declare shows that a declarative language can indeed be made configurable.

• More case studies are needed.

• Problems: − few existing

declarative process models

− adoption is difficult

procedural declarative

non-

confi

gurable

confi

gurable

Advertisement: Tools supporting Declare and/or Process Configuration

PAGE 30

http://www.win.tue.nl/declare/http://www.processmining.org

discovering

Declare

models

conformance

checking

using Declare

models

enacting

Declare

models configuratio

n

support