1. Social Structures in Tropos Manuel KolpPaolo GiorginiJohn Mylopoulos U Louvain U Trento U Toronto U Louvain U Trento U Toronto First Tropos Workshop, Trento, 15-16 November 2001 http://www.cs.toronto.edu/km/tropos

2. Social Structures in Tropos 2 Motivation Narrowing the gap between requirements modeling and system design Narrowing the gap between requirements modeling and system design Same concepts for both phases: Social and intentional structures Same concepts for both phases: Social and intentional structures Coordinated & autonomous with goals & social dependencies Coordinated & autonomous with goals & social dependencies Concepts from organization theory, … and early requirements modeling Concepts from organization theory, … and early requirements modeling Ontology: 3 levels (Macro, micro, atomic) Ontology: 3 levels (Macro, micro, atomic)

3. Social Structures in Tropos 3 Social Ontology 3 Levels 3 Levels 1 Macrolevel : Organizational Styles (Organization Theory) 1 Macrolevel : Organizational Styles (Organization Theory) –Vertical Integration, Pyramid, Joint Venture, Structure in 5, Bidding, Hierarchical Contracting, Co-optation, Takeover 2 Micro level : Social Patterns (Agent, COOPIS Community) 2 Micro level : Social Patterns (Agent, COOPIS Community) –Broker, Matchmaker, Contract-Net, Mediator, Monitor, Embassy, Wrapper, Master-Slave,... 3 Atomic : Social and intentional concepts – i* 3 Atomic : Social and intentional concepts – i* –goals, actors, social dependencies, …

4. Social Structures in Tropos 4 Organization Theory Mintzberg, Scott, Galbraith, … Mintzberg, Scott, Galbraith, … Studies alternatives and models for (business) organizations Studies alternatives and models for (business) organizations Model the coordination of business stakeholders -- individuals, physical or social systems -- to achieve common (business) goals. Model the coordination of business stakeholders -- individuals, physical or social systems -- to achieve common (business) goals.

5. Social Structures in Tropos 5 Structure in 5 Operational core : basic operations -- the input, processing, output associated with running the organization. Operational core : basic operations -- the input, processing, output associated with running the organization. Strategic apex : executive, strategic decisions. Strategic apex : executive, strategic decisions. Support : Assists the operation core for non-operational services outside the basic flow of operational procedures. Support : Assists the operation core for non-operational services outside the basic flow of operational procedures. Technostructure : standardizes the behavior of other components, help the system adapt to its environment. Technostructure : standardizes the behavior of other components, help the system adapt to its environment. Middle line : Actors who join the apex to the core. Middle line : Actors who join the apex to the core.

6. Social Structures in Tropos 6 Structure in 5 and Joint Venture

7. Social Structures in Tropos 7 Bidding and Vertical Integration

8. Social Structures in Tropos 8 Structure in 5 in detail (from Mintzberg)

9. Social Structures in Tropos 9 Formal Analysis Dependency StrategicManagement Type SoftGoal Mode achieve Depender MiddleAgncy Dependee Apex Attribute constant objective : MiddleAgencyObjective Creation condition  objective.strategy condition  objective.strategy trigger Pursue(objective) Fulfillment condition for depender  ma-strategy: MiddleAgencyStrategy  ma-strategy: MiddleAgencyStrategy (  org -strategy: OrgStrategy (objective.strategy=strategy ^ consistent(ma-strategy,org-strategy)) consistent(ma-strategy,org-strategy)) [the StrategicManagement dependency is created when there is no strategy for a given middle agency objective, and it is fulfilled when there exists a middle agency strategy consistent with all the strategies of the organization]

10. Social Structures in Tropos 10 The Mobile Robot Case Study Mobile robot activities: Mobile robot activities: - Acquiring the input from sensors, - Controlling the motion of moveable parts, - Planning its future path. External Factors: External Factors: - Obstacles may block the path, - Sensor inputs may be imperfect, - The robot may run out of power, - Mechanical limitations may restrict accuracy - The robot may manipulate hazardous materials, - Unpredictable events may leave little time for responding.

11. Social Structures in Tropos 11 Conventional Architectures Task Trees : Hierarchies of tasks. Parent tasks initiate child tasks. Temporal dependencies between tasks permit selective concurrency. Layers Control Loop

12. Social Structures in Tropos 12 Organizational Architectures: Structure-in-5

13. Social Structures in Tropos 13 Quality Attributes for Mobile Robots Coordinativity. A mobile robot has to coordinate the actions it undertakes to achieve its objective with the reactions forced on it by the environment. Coordinativity. A mobile robot has to coordinate the actions it undertakes to achieve its objective with the reactions forced on it by the environment. Predictability. For a mobile robot, never will all the circumstances of the operation be fully predictable. The architecture must provide the framework in which the robot can act even when faced with incomplete information. Predictability. For a mobile robot, never will all the circumstances of the operation be fully predictable. The architecture must provide the framework in which the robot can act even when faced with incomplete information. Failability-Tolerance. Must prevent the failure of the robot’s operation and its environment. Local problems like reduced power supply, unexpectedly opening doors should not necessarily imply the failure of the mission. Failability-Tolerance. Must prevent the failure of the robot’s operation and its environment. Local problems like reduced power supply, unexpectedly opening doors should not necessarily imply the failure of the mission. Adaptability. Application for mobile robots frequently requires experimentation and reconfiguration. Changes in assignments require regular modification. Adaptability. Application for mobile robots frequently requires experimentation and reconfiguration. Changes in assignments require regular modification.

14. Social Structures in Tropos 14 Strengths and Weaknesses of Robot Architectures LoopLayers Task Tree S-in-5Joint-Vent. Coordinativity-- + -+ -+ -+ - + ++ ++ ++ + + ++ ++ ++ + Predictability + -+ -+ -+ -+ + -+ -+ -+ -+ + ++ ++ ++ + Failability-Tol.+ + -+ -+ -+ -+++ Adaptability + -+ -+ -+ - + -+ -+ -+ -++ + -+ -+ -+ -

15. Social Structures in Tropos 15 Coordinativity Control loop: Simplicity is a drawback when dealing with complex tasks, no leverage for decomposing the software into more precise components. Control loop: Simplicity is a drawback when dealing with complex tasks, no leverage for decomposing the software into more precise components. Layers: services and requests between adjacent layers. Transactions not always straight-forward. Need to skip layers to coordinate behavior. Layers: services and requests between adjacent layers. Transactions not always straight-forward. Need to skip layers to coordinate behavior. Task trees: clear separation of action and reaction. Allows incorporation of concurrent agents. Components have little interaction with each other. Task trees: clear separation of action and reaction. Allows incorporation of concurrent agents. Components have little interaction with each other. Structure-in-5: separates data (sensor control, interpreted results, world model) from control (motor, navigation, scheduling, planning and user- level) hierarchies Structure-in-5: separates data (sensor control, interpreted results, world model) from control (motor, navigation, scheduling, planning and user- level) hierarchies Joint venture: Components interact via the joint manager for strategic decisions. They indicate their interest, the joint manager returns them such information or mediates the request to other partner component. Joint venture: Components interact via the joint manager for strategic decisions. They indicate their interest, the joint manager returns them such information or mediates the request to other partner component.

16. Social Structures in Tropos 16 NFR Analysis: Selecting Architectures

17. Social Structures in Tropos 17 Mobile Robot Organizational Environment With the Bidding Style 0. task auctionned Issuer Auctioneer Bidder

18. Social Structures in Tropos 18 Using These Social Structures at All Steps Early requirements (organization modeling): stakeholders (people, organizations, systems), goals and dependencies. Early requirements (organization modeling): stakeholders (people, organizations, systems), goals and dependencies. Late requirements, the system-to-be as one or a few social actors (blackbox) participating in the organization model. Late requirements, the system-to-be as one or a few social actors (blackbox) participating in the organization model. Architectural design, the system as an organization of actors Architectural design, the system as an organization of actors Detailed design, system actors transformed into agents by means of social patterns Detailed design, system actors transformed into agents by means of social patterns Implementation: Multi-agent system as societies of individuals to achieve particular, possible common goals. Implementation: Multi-agent system as societies of individuals to achieve particular, possible common goals.

19. Social Structures in Tropos 19 Media Industry: Early Requirements Organization Modeling with the Joint Venture Style

20. Social Structures in Tropos 20 Media Industry: Late Requirements With the Vertical Integration Style With the Bidding Style

21. Social Structures in Tropos 21 Media Industry: Architectural Design E-business styles: on web, protocols, technologies Not on business processes, NFRs No organization of the architecture, conceptual high- level perspective

22. Social Structures in Tropos 22 Social Patterns Embassy Mediator Contract-Net

23. Social Structures in Tropos 23 Detailed Design with Social Patterns

24. Social Structures in Tropos 24 Conclusion System described with concepts from requirements and organization modeling System described with concepts from requirements and organization modeling  Narrows the gap requirements / design  Narrows the gap requirements / design Multi-Agent Architectures as social and intentional structures Multi-Agent Architectures as social and intentional structures Best suited to open, dynamic and distributed applications Best suited to open, dynamic and distributed applications Ontology on 3 levels: Ontology on 3 levels: –Macro: Organization Styles –Micro: Social Patterns –Atomic: i* - goals, actors, social dependencies, …

25. Social Structures in Tropos 25 Discussion: Problems, Suggestions ??? Organization Theory why not Sociology, Group Dynamics, … Organization Theory why not Sociology, Group Dynamics, … Formalization at the metalevel: Makes sense, not too abstract?? Formalization at the metalevel: Makes sense, not too abstract?? Formal result: ex.: sound and complete, instantiation ethics Formal result: ex.: sound and complete, instantiation ethics Convincing real-world size case study: Organization Modeling, Early (Business) Requirements Convincing real-world size case study: Organization Modeling, Early (Business) Requirements Styles vs Patterns Macro level Microlevel Styles vs Patterns Macro level Microlevel Convincing for organization theorists, sociologists, ontologists?? Convincing for organization theorists, sociologists, ontologists?? NFR evaluation: intuitive vs formal for Requirements/Architectures NFR evaluation: intuitive vs formal for Requirements/Architectures WRT Conventional Architectures: pros & cons, reevaluation WRT Conventional Architectures: pros & cons, reevaluation Methodology: Social Structures at all steps makes sense? Methodology: Social Structures at all steps makes sense?