Chapter 18 Process Configuration

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Chapter 18Process Configuration

Florian Gottschalk

Marcello La Rosa


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© 2009, www.yawlfoundation.org

Overview

1. Introduction to Configurable Process Models

2. Process Configuration in YAWL

3. Questionnaire-driven Approach for Process Configuration

4. Tool Support

5. Conclusions


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Tape variant Film variant

ConfigurableProcess Model

Prepare footage for edit

Offline edit

NegmatchingOnline edit

Tape Film

What is a configurable process model?

commonality

=variability

+variation point

common practice forTape shooting

Prepare footage for editing

Offlineediting

Onlineediting

Integrated representation of multiple variants of a same process in a given domain, which can be configured for a specific setting, leading to an indivi-dualized process model.

common practice forFilm Shooting

Prepare footage for editing

Offlineediting

Negmatching


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Offline edit

NegmatchingOnline edit

Tape Film

Configurable Process Models in the Process Lifecycle

design configuration individualization implementation execution


Offline edit


Offline edit

Online edit

Prepare footage for edit3

Offline edit3

Online edit3


Offline edit2

Online edit2


Offline edit1

Online edit1

Configurableprocess model

Online edit

Tape

Negmatching

Film

Configured process model(Tape shooting)

Derived model(Tape shooting)

Derived instances(Tape shooting)

configurable model designdiagnosis

configuration and individualization

implementation

execution

design

implementationexecution

diagnosis


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Features of a Configurable Process Model

• should guide the user to a model that fits his requirements

• must be able to generate all possible process variants

• must be a complete, integrated set of all possible process variants

• is the least common multiple of all process variations


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Variant BSuperclassSuperclass Configurable ModelVariant A

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Inheritance Inheritance

Subclass

Configuration Configuration

A Theoretical explanation

Inheritance of workflow behavior:


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• Blocking

• Hiding– also called skipping

Configuration Techniques

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ττhidehide

hide


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Port Configuration

TaskPorts

enabled

blocked

hidden (skipped)


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Port types in YAWL

Flow of tokens is determined by functions assigned to a YAWL task:•join input ports•split output ports•rem cancellation port•nofi multiple instance configuration


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Input ports (inflow)

• XOR-join• Task is enabled if a token arrives from any arc

One input port for each incoming arc

• AND-join• Task is enabled if tokens are arriving from all arcs

One input port for the whole task

• OR-join• Task is enabled if tokens are arriving from all arcs from which

a token can potentially arrive

One input port for the whole task


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Output ports (outflow)

• XOR-split• Task releases one token via one of the arcs

One output port for each outgoing arc

• AND-split• Task releases tokens via all arcs only

One output port for the whole task

• OR-split• Task can release tokens via any combination of outgoing arcs

One output port for every combination of outgoing arcs


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Configuration Example

(A, B, C, E) or (A, B, D, E)(A, B, C, E)(B, C, E)


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Cancellation ports (inflow)

• Cancellation also represents an inflow of tokens, but can also take 0 tokens

• Takes the maximum number of available tokens, similar to the OR-joinOne cancellation port for the whole task

• Hiding of Cancellation ports makes no senseNo skippable action between the activation of the cancellation

port and the outflow of tokens


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Multiple Instance configuration

1. Increase of the minimal number of instances to be started

2. Decrease of the maximal number of instances to be started

3. Increase of the threshold value

4. Restrict dynamic creation of instances to static creation


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[1 , 3 , inf, static]


1. Increase of the minimal number of instances to be started

2. Decrease of the maximal number of instances to be started

create Instances

thresholdInstance

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Instance 1

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1,21,32,3

1,2,3

123

1,21,32,3

1,2,3


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[3, 3, 2 , static]

3. Increase of the threshold value

create Instances

threshold 3

Instance 2

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Instance 1

Instance 3

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threshold 2

threshold 2

threshold 2

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[1 , 3 , inf, dyn]

4. Restrict from dynamic to static instance creation

create Instances

thresholdInstance

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Instance 1

Instance 3

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Transforming a port configuration

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cTask B

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Example 1

Transforming a port configuration: the OR-split


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cTask C

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cTask C

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Example 2



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Example 3



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Questionnaire-driven configuration

• Configuring a process model can be difficult and time-consuming, due to:

– size of the variability space,– complexity of the domain.

• Domain experts usually have little or no knowledge about modeling notations (e.g. in the screen business).

• Need to facilitate the configuration of process models by domain experts, without requiring process modeling knowledge.


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Questionnaire-based approach

• Configuration can be simplified if carried out by answering a set of questions no need to be aware of modeling notations.

• The basic concepts of the approach are questions and domain facts:– a question is composed of a set of domain facts;– a domain fact encodes a business choice and can be set to “true” or “false”.

• Variation points in the process model are mapped to boolean expressions over domain facts.

• Questions may affect one or multiple variation points:

Online cut Negmatching

c2

SEQa SEQbV

a2 b2

2 2

q1: What is the allocated budget for the project?

f1: Low

f2: Medium

f3: High

q4: How is the Picture Cut to be performed?

f12: Negmatching

f11: Online cut


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Domain constraints

• The configuration space of the domain is restricted by a set of propositional logic domain constraints over the domain facts.

• By means of domain constraints, answers to questions may be determined by previous answers.


f12: Negmatching

f11: Online cut

DC10: f11 f12

DC11: f10 ⇒ f12


f12: Negmatching

f11: Online cut

q3: Which shooting media have been used?

f10: Film shooting

f9: Tape shooting

DC10

DC11


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f12: Negmatching

f11: Online

q5: Which are the expected deliverables?

f13: Tape finish

f14: Film finish

f15: New media finish


f1: Low

f2: Medium

f3: High

q2: What are the primary distribution channels?

f4: Cinema

f5: TV

f6: Home

f7: Mobile

f8: Internet


f10: Film shooting

f9: Tape shooting

mapping question-d. fact

domain fact

question

Questionnaire model


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f12: Negmatching

f11: Online


f13: Tape finish

f14: Film finish



f1: Low

f2: Medium

f3: High


f4: Cinema

f5: TV

f6: Home

f7: Mobile

f8: Internet


f10: Film shooting

f9: Tape shooting


domain fact

question

Order dependencies


domain fact

question x y

x y

x partially depends on y

x fully depends on y


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Process ModelQuestionnaire Model

Mapping

Mapping process models to questionnaire models

A mapping links process facts to domain facts:

The mapping ensures domain compliance and process model correctness.

C-EPC

C-YAWL


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Post-production

finished

New mediafinish e

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Filmfinish

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a4

dTapefinish

Telecinetransfer

Record DFM

SEQa4V

SEQb4

Tape finish

Constraints in action

f6: Home

f4: Cinema

f5: TV

f7: Mobile

f8: Internet

q2:What are the primary distribution channels?


f13: Tape finish

f14: Film finishq5: Which are the expected

deliverables?

DC6 DC8

MC22

MC25

PC4

DC6: f5 ⇒ f13

DC8: f8 ⇒ f15

MC22: pON ⇔ f13d

MC25: pON ⇔ f15e

PC4: pON ⇒ pSEQd

c4

b4

Domain constraints Mapping Process constraints

New mediafinish


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=

Application of the approach

Interactive Questionnaire Configurable Process Model

Individualized Model

answers

input to

Questionnaire model Mapping

+q7: What Film format has

been shot?

f19: 16mm film

f20: 35mm film

f21: 65mm film


f12:Negmatching

f11: Online cut


f13: Tape finish

f14: Film finish

f15: New Media finish


f1: Low (≤ 250,000 US)

f2: Medium (> 250,000 US, ≤ 1.5mil US)

f3: High (> 1.5mil US)


f4: Cinema

f5: TV

f6: Home

f7: Mobile

f8: Internet


f10: Film shooting

f9: Tape shooting

q6: What Tape formathas been shot?

f16: Analogue tape

f17: SD digital tape

f18: HD digital tape

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Tape shoot finished

Film shoot finished

Prepare tape for edit

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Offline

Online suite cut

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Film-based cut

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Post-production

finished

Footage preparedfor edit

Edit finished

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Film finishTape finish

Telecine transfer

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Record Digital Film Master

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New media finish

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Tape shoot finished

Prepare tape for edit

Offline edit

Online edit

Post-production

finished

Footage preparedfor edit

Edit finished

New media finish

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1a


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Tool support: Synergia

• Open-source• Modular: 6 standalone applications,• Provides end-to-end support for process model configuration,• Independent of specific modeling notations,• Supports C-EPC and C-YAWL.

Mapping(.cmap)

C-EPC model(.epml)

ConfiguredC-EPC (.epml)

EPC(.epml)

Questionnaire Model (.qml)

ConfiguredC-YAWL (.yawl)

YAWL Engine spec. (.yawl)

C-YAWL model(.yawl)

Quaestio

Mapper ProcessConfigurator

ProcessIndividualizer

C-EPC Designer

Configurationmodel (.cml)

QuestionnaireDesigner


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Discussion

• Is there a need for configurable models?– Do you have the same experience that highly-standardized

processes (such as the Order Fulfillment example) are still adapted to individual needs?

• Is it feasible to create configurable models?– What do you think about how we individualized the Order Fulfillment

model compared to the intended use of your software?

• Are configurable models useful?– Can you imagine that you provide similar models which can be

adapted “without drawing arcs and nodes”?


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Conclusions

• Process Configuration is a viable mechanism to automate the derivation of customized models from a reference model in a specific domain

• Process Configuration in YAWL is grounded in the concept of Inheritance of Workflow Behavior and is achieved via 2 operators: hide, block

• The Questionnaire-based approach facilitates the configuration of (complex) process models such as the Order Fulfillment example by non-modeling experts

• Tool support is available with the Synergia toolset


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For more information…

…visit www.processconfiguration.com

Chapter 18 Process Configuration

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