Post on 08-May-2015
description
i* Modeling of Agent-based RE Processes – A Basic TutorialProcesses – A Basic Tutorial
ROLE PLE Expert WorkshopROLE PLE Expert WorkshopLeicester, July 23, 2009
Ralf Klamma
Ch i f C t S i 5Chair of Computer Science 5,RWTH Aachen University, Germany
© www.role-project.eu
Technical LeaderCommunity Facilitator
Motivation - Traditional RE
• Emphasis on Late Phase RE• Emphasis on Late Phase RE• OO RE (Classes/Objects)• Ill-suited for Socio-Technical Systems
“What“ & “How“ but not “Why“• What & How , but not Why• Neglection of Stakeholder Interestsg• Early Choice between Alternatives
Agent-Oriented RE
© www.role-project.eu
R. Klamma, RWTH Aachen 2
Motivation - Agent-Oriented RE
• Intentional Agents pursuing Goalsg p g• Focus on Early Phase RE
S l R l t H /SW A t• Seamless Replacement Human/SW Agent• Continuous Adaptabilityp y
– New ComponentsNew Requirements– New Requirements
• Flexibility– Alternative Ways towards Goals– Open towards Unknown Components
© www.role-project.eu
Open towards Unknown ComponentsR. Klamma, RWTH Aachen 3
What is an Agent?
• Person, Organisation, Software• BDI: Beliefs – Desires – IntentionsBDI: Beliefs Desires Intentions• Autonomous, Flexible, Social• Goal-Oriented• Partial Description of Human AgentsPartial Description of Human Agents• Full Formal Description of SW Agents
© www.role-project.eu
R. Klamma, RWTH Aachen 4
The i* Modeling Framework
• Developed by Eric Yu• Distributed Intentionality (Actors with Goals) • 2 Model Types• 2 Model Types
– Strategic Dependency (SD)• Intentional, strategic relationships among actors• Actor Diagram
– Strategic Rationale (SR)• Rationale behind dependenciesp• Analysis of alternatives & dependency fulfillment• Goal Diagram
© www.role-project.eu
gR. Klamma, RWTH Aachen 5
i* - Syntax Element Overview
• ActorActor• Actor Associations• Goal, Softgoal, Task, Resource, • Links• Links
– Strategic Dependency (SD)– Strategic Rationale (SR)
• Decomposition• Means-Ends• Contributions
© www.role-project.eu
R. Klamma, RWTH Aachen 6
Actor, Agent, Role, Position
• Actor– Abstract representation for active entity– Carries out actions to reach goals
• Agent– Concrete manifestation of actor
/S f– Human/Software
• RoleDomain specific behaviour of actor– Domain-specific behaviour of actor
– Played by actor
• PositionPosition– Covers set of roles– Occupied by agent
© www.role-project.eu
p y g
R. Klamma, RWTH Aachen 7
SD - Actor Associations
• 6 Types:plays– plays
– occupies– covers– is ais a– is Part Of
is Instance– is Instance
© www.role-project.eu
R. Klamma, RWTH Aachen 8
SD - Strategic Dependencies
Four Dependency Types:Four Dependency Types:• Goal (fulfill) • Task (complete)• Softgoal (fulfill) • Resource (provide)
© www.role-project.eu
R. Klamma, RWTH Aachen 9
SD - Vulnerability
• Vulnerability implied with dependencies• 3 Degrees of strength
– Open: slightly affects dependerOpe s g y a ec s depe de– Committed: causes action in depender – Critical: causes all depender actions to fail
© www.role-project.eu
Critical: causes all depender actions to failR. Klamma, RWTH Aachen 10
SR – Actor Boundaries
• Intentional boundary of actory• Elements within explicitly desired by actor
A t t d d th ’ i t ti• Actor must depend on others’ intentions• Actor is depended upon by others
© www.role-project.eu
R. Klamma, RWTH Aachen 11
p p y
SR – Means-Ends Links
• Relationship between – an endan end– a means for attaining end
E d G l ( h t)• End: Goal (what)• Means: Task (how)
© www.role-project.eu
R. Klamma, RWTH Aachen 12
( )
SR – Decomposition Links
Task Goal Decomposition: Subgoal• Task-Goal Decomposition: Subgoal• Task-Task Decomposition: Subtask• Task-Resource Decomposition: ResourceFor• Task-Softgoal Decomposition: SoftgoalFor
© www.role-project.eu
as So tgoa eco pos t o So tgoa oR. Klamma, RWTH Aachen 13
SR – Contribution Links
• contribution to fulfillment of softgoals• contribution to fulfillment of softgoals• 9 Types:
MakeSome+
BreakSome
UnknownAnd Some+
Help Some- Hurt
And Or
© www.role-project.eu
R. Klamma, RWTH Aachen 14
SJTU Peer Teaching Scenario (SD)
© www.role-project.eu
R. Klamma, RWTH Aachen 15
SJTU Peer Teaching Scenario (SR)
© www.role-project.eu
R. Klamma, RWTH Aachen 16
Further Information – I* Wiki
• Available at http://istar.rwth-aachen.dep• Tutorials & Modeling Guidelines
T l• Tools• Publications categorized by domaing y
– Requirements EngineeringTrust in Multi Agent Systems– Trust in Multi Agent Systems
– Variability and Personalization– Knowledge Management
© www.role-project.eu
R. Klamma, RWTH Aachen 17