i* Modeling of Agent-based RE Processes – A Basic Tutorial ROLE PLE Expert WorkshopLeicester, July 23, 2009 Slides produced by Dominik Renzel

1. i* Modeling of Agent-based RE
Processes – A Basic Tutorial
ROLE PLE Expert Workshop
Leicester, July 23, 2009
Ralf Klamma
Chair f C
Ch i of Computer Science 5,
t S i 5
RWTH Aachen University, Germany
Technical Leader
Community Facilitator
© www.role-project.eu

2. Motivation - Traditional RE
• Emphasis on Late Phase RE
• OO RE (Classes/Objects)
• Ill-suited for Socio-Technical Systems
• “What“ & “How“, but not “Why“
What How Why
• Neglection of Stakeholder Interests
g
• Early Choice between Alternatives
 Agent-Oriented RE
R. Klamma, RWTH Aachen 2
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3. Motivation - Agent-Oriented RE
• Intentional Agents p
g pursuing Goals
g
• Focus on Early Phase RE
• Seamless R l
S l Replacement Ht Human/SW A
/SW Agent
t
• Continuous Adaptability
p y
– New Components
– New Requirements
• Flexibility
– Alternative Ways towards Goals
– Open towards Unknown Components
R. Klamma, RWTH Aachen 3
© www.role-project.eu

4. What is an Agent?
• Person, Organisation, Software
• BDI: Beliefs – Desires – Intentions
• Autonomous, Flexible, Social
• Goal-Oriented
• Partial Description of Human Agents
• Full Formal Description of SW Agents
R. Klamma, RWTH Aachen 4
© www.role-project.eu

5. The i* Modeling Framework
• Developed by Eric Yu
• Distributed Intentionality (Actors with Goals)
• 2 Model Types
– Strategic Dependency (SD)
• Intentional, strategic relationships among actors
• Actor Diagram
– Strategic Rationale (SR)
• Rationale behind dependencies
p
• Analysis of alternatives & dependency fulfillment
g
• Goal Diagram
R. Klamma, RWTH Aachen 5
© www.role-project.eu

6. i* - Syntax Element Overview
• Actor
• Actor Associations
• Goal, Softgoal, Task, Resource,
• Links
– Strategic Dependency (SD)
– Strategic Rationale (SR)
• Decomposition
• Means-Ends
• Contributions
R. Klamma, RWTH Aachen 6
© www.role-project.eu

7. Actor, Agent, Role, Position
• Actor
– Abstract representation for active entity
– Carries out actions to reach goals
• Agent
– Concrete manifestation of actor
– Human/Software
/S f
• Role
– Domain specific behaviour of actor
Domain-specific
– Played by actor
• Position
– Covers set of roles
– Occupied by agent
p y g
R. Klamma, RWTH Aachen 7
© www.role-project.eu

8. SD - Actor Associations
• 6 Types:
– plays
– occupies
– covers
– is a
– is Part Of
– is Instance
R. Klamma, RWTH Aachen 8
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9. SD - Strategic Dependencies
Four Dependency Types:
• Goal (fulfill) • Task (complete)
• Softgoal (fulfill) • Resource (provide)
R. Klamma, RWTH Aachen 9
© www.role-project.eu

10. SD - Vulnerability
• Vulnerability implied with dependencies
• 3 Degrees of strength
– Open: slightly affects depe de
Ope s g y a ec s depender
– Committed: causes action in depender
– Critical: causes all depender actions to fail
R. Klamma, RWTH Aachen 10
© www.role-project.eu

11. SR – Actor Boundaries
• Intentional boundary of actor
y
• Elements within explicitly desired by actor
• Actor
A t must depend on others’ i t ti
td d th ’ intentions
• Actor is depended upon by others
p p y
R. Klamma, RWTH Aachen 11
© www.role-project.eu

12. SR – Means-Ends Links
• Relationship between
– an end
– a means for attaining end
• E d G l ( h t)
End: Goal (what)
• Means: Task (how)
( )
R. Klamma, RWTH Aachen 12
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13. SR – Decomposition Links
• Task-Goal
Task Goal Decomposition: Subgoal
• Task-Task Decomposition: Subtask
• Task-Resource Decomposition: ResourceFor
• Task-Softgoal Decomposition: So tgoa o
as So tgoa eco pos t o SoftgoalFor
R. Klamma, RWTH Aachen 13
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14. SR – Contribution Links
• contribution to fulfillment of softgoals
• 9 Types:
 Make  Break  Unknown
 Some+  Some
Some-  And
 Help  Hurt  Or
R. Klamma, RWTH Aachen 14
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15. SJTU Peer Teaching Scenario (SD)
R. Klamma, RWTH Aachen 15
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16. SJTU Peer Teaching Scenario (SR)
R. Klamma, RWTH Aachen 16
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17. Further Information – I* Wiki
• Available at http://istar.rwth-aachen.de
p
• Tutorials & Modeling Guidelines
• Tools
T l
• Publications categorized by domain
g y
– Requirements Engineering
– Trust in Multi Agent Systems
– Variability and Personalization
– Knowledge Management
R. Klamma, RWTH Aachen 17
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