business process flexibility in service composition

[email protected] IESS’11| 2/17/11 1

Business process flexibility in service composition : an experiment using a PLM-based scenario


Safa HACHANI [email protected]

Grenoble Institute of Technology G-SCOP Laboratory- France

Encadrants : Lilia GZARA (G-SCOP) et Hervé VERJUS (LISTIC) [email protected]

[email protected]



Business process flexibility Requirements

Plan

Evaluating BPEL against the process flexibility requirements

Conclusion

Business Process environment overview

Business process automation & service standards

Evaluating PDDL against the process flexibility requirements




•  « The sequence of steps that govern enterprise solutions operations to achieve business objectives » F.B. Vernadat, 2007

•  Businesses today requires to quickly adapt and change business processes to meet customer needs, market conditions, new operational or organizational requirements

Business Process Definition

Assigning production orders process

BP Environment Overview

Change in assigning production orders process



Business Process Automation

Business Process automation and service standard

•  Business Process Management becomes the enabler of business process automation –  Improve the speediness and quality of a business process –  BPM activities : Modeling, Execution and Monitoring

How does it work? - Storing the input model (process template)

- Executing the process instance - Instantiating the process template

Workflow Management system

Terminology and Glossary, 3rd Edition. Document No WFMC-TC-1011

« Provides procedural automation of a business process by management of the sequence of work activities and the invocation of appropriate human and/or IT resources associated with the various activity steps.»



1

No run time modification

Redefine new template, re-instantiate and rerun

We need a less rigid solution to

Support BP changes

Workaround process definition at run time

Time t0 t1

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3

4

1

2

3 1

2

3

4

Which alternatives for BP Management

Stiffness of workflow system





•  SOA promote the composition of reusable and loosly coupled independent services

•  Service « Provider of reusable functions in an implementation-independent language that is loosely coupled to other functions»

•  SOA provide mechanisms for making process automation more agile

R. Credle, 2008

Business process defined as service composition

•  The survival of process is dependent on how flexible the service compositions are.



Process flexibility Requirements

•  A services composition can be seen as a collection of services Relationships.

•  Process definitions are defined on top of these relationships.

Levels of process flexibility

The flexibility on process definition implies requirements on flexibility of the services relationships

Service based-Process definition: information exchange What? What tasks need to be performed? Which? Which services are involved in the process definition?



Process Flexibility Requirements

Evaluating BPEL against the process flexibility requirements

Conclusion


Business process automation & service standards


Plan




•  Activities-based and goal-based methods •  Traditional orchestration: Activities based methods (BPEL, WS-CDL, BPML, etc.)

Business Process Execution Language (BPEL).

•  Goal based composition methods, Artificial Intelligence planning (CSSL, PDDL, etc.)

Process definition is generated automatically using planners and planning language such as Planning Domain Definition Language (PDDL)

•  Do they really support flexible business processes? •  How can BPEL or PDDL enable business process flexibility achievement?

Service composition methods for process definition



Simple Example: Updating Product Attachment

Updating Product Attachment Process



•  Business Process Execution Language (BPEL) –  Is the standard for specifying service-based business processes –  Process can be specified, using BPEL, as a flow between services’

operations and the process –  specifies an executable process that involves message exchanges with

other partners (other services)

BPEL Process structure Services used to define

the process

Evaluating BPEL against process flexibility requirements

BPEL Process structure

Services used to define the process

Updating Product Attachment process



•  The interaction between partners occurs through service interfaces.

•  This relationship is allowed thanks to partner link type.

–  A partner link type binds a port type the process offers to a partner and a port type the process requires from the corresponding partner.

Partners relationship in BPEL Partner Link Type between ModifProcess and ModificationAttachement service


role names

port type



•  Process definition contains the description of the behavior for handling a modification request

–  Which operations needs to be invoked : Interaction activities ( <invoke>, <receive>, <assign>, etc.)

–  In what order : structured activities ( <sequence>,<switch>, <while>, <scope>, etc.)

BPEL interaction model for the Updating Product Attachment process

Interaction activities: reference a partner link and a port type

operation


Structure of processing section




•  Services relationship flexibility requirement –  Roles used by process are tied to services interfaces by service linkTypes.

No ability to change inter-services relationships

•  Process definition flexibility requirement –  Predefined sequence of activities,

–  The process logic (’what’) directly refer to services’ operations (’which’).

No ability to change service binding or process behavior

How does it

work?




•  Application of AI planning to the service composition problem.

•  Planning Domain Defintion Language (PDDL)

Components of a PDDL; planning problem: • Objects: set of things in the world that interest us.

(Product Reference (Ref), Product Attachment (Doc), etc.) • Predicates: defines properties of objects that we are interested in; can be true or false.

(Updated Doc), etc.

• Initial state: denotes the state of the world that we start in. (Known Ref )(Not (Updated Doc)), etc.

• Goal specification: denotes the goal state of the object the planner attempt to reach (And (IdentifiedAttach Ref Doc)(updated Doc)(chekedIn Doc))

• Actions: are the ones the planners can perform in order to change the state of the world. (searchAttachment, initiateModif, modification and endModif)



•  How can we transform services composition problems into AI planning problems ?


Mapping between services and PDDL models

–  Each service operation can be specified as an action in the planning domain.

Objects and Properties that we are interested in Actions

Objects and Properties that we are interested in Actions

–  Process definition: the initial states of the system under which the process will be executed and the goal states after the execution of the process.




•  Services relationships flexibility –  Problem goal (process logic) is defined on top of predicates and that not refer to the

actions (which): possibility to use any action which offers the needed computation. ability to change inter-services relationships

•  Process definition flexibility

–  Changing the states in the base allow changing the process definition at run time

ability to change service binding or process behavior

How does it

work?

Planner Predicates

Actions

Object

Initial state

Goal

Plan states

•  Every time an action is executed the planner generates again a new plan according to the new states in the base and to the goal specified in the problem

delegate



Conclusion

•  Businesses today requires to quickly adapt and change business processes to satisfy customers and compete in market

To reflect this changes automated support for business process needs to be flexible.

•  Process flexibility Requirements for an effective service-based BP Automation.

–  Process definition flexibility : ability to change service binding

–  Service relationships flexibility : ability to change inter-service relationships

•  Services-based BP Automation needs more investigations for PDDL direction

Interesting : generates process definition automatically, locates the correct services, dynamically changes the process at runtime

BPEL PDDL PLM-based scenario

-  Activities-oriented service composition methods

-  Goal-oriented methods -  Using AI planning languages

Flexible but hard to define and understand the specification by non-technical users

Simplified comprehension of service-based process, results in rigid BP definition.



Thank you for your attention!!

business process flexibility in service composition

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