Component-Based Agent Frameworks And SoccerBeans

1. Component-Based Agent Frameworks And SoccerBeans Hrishikesh J. Goradia CSCE 782 Fall 2003 University of South Carolina CSCE 782 – CBAF & SoccerBeans

2. Component-Based Software Engineering Techniques Current Agent Framework Development Techniques Component-Based Agent Framework Component-Based Agent Framework CSCE 782 – CBAF & SoccerBeans

3. Applications Domain specific Agent Framework CBAF specifications Development Environment Component Based Agent Framework Component-Based Agent Framework CSCE 782 – CBAF & SoccerBeans

4. Applications Domain specific Agent Framework CBAF specifications Development Environment Component Based Agent Framework Component-Based Agent Framework • Components encapsulate the underlying complexities of the framework • Designing MAS using CBAF is simple • CBAF is domain-specific CSCE 782 – CBAF & SoccerBeans

5. CBAF Specifications • Agent framework must be designed as a set of independent, self-contained, highly specialized components. • Commonalities of various applications in a domain must be discovered and developed as domain-specific components in the framework. • A component must be interface-centric and architecture-centric. • Components must be designed such that each performs a unique, singular function. Conversely, every function to be performed by an agent in a domain application must be defined as a component in the framework. CSCE 782 – CBAF & SoccerBeans

6. CBAF Specifications • Framework designers must strive for the development of “context-free” components. • The agent framework must provide a look-up service for the agents. Message transport must be facilitated through event triggering. • The framework must facilitate the integration of its components to create different agent plans (also called as activities). It must also provide a way to compose these activities with the individual agents. • Agent framework must include the following types of components: • Agent component(s) • Activity component(s) • Decision components • Behavior components CSCE 782 – CBAF & SoccerBeans

7. Behavior Components Decision Components kick dash spatial location catch AND move OR Activity 2 Activity 1 Activity n . . . Pool of Activities 1 n Agent component Activity component Individual Agent Sample CBAF Implementation (RoboCup domain) CSCE 782 – CBAF & SoccerBeans

8. Behavior Components Decision Components kick dash spatial location catch AND move OR Activity 2 Activity 1 Activity n . . . Pool of Activities 1 n Agent component Activity component Individual Agent Sample CBAF Implementation (RoboCup domain) Behavior components • A behavior component must represent an agent’s action • Each rule set in a plan must be mapped to a behavior component • The framework must provide every possible atomic action for an agent in the particular domain as a behavior component CSCE 782 – CBAF & SoccerBeans

9. Behavior Components Decision Components kick dash spatial location catch AND move OR Activity 2 Activity 1 Activity n . . . Pool of Activities 1 n Agent component Activity component Individual Agent Sample CBAF Implementation (RoboCup domain) Decision components • Represents a rule used during plan generation for an agent • The framework must facilitate the combining of various decision components to define new rules • The framework must include all the decision components to accommodate the creation of any rule for a plan CSCE 782 – CBAF & SoccerBeans

10. Behavior Components Decision Components kick dash spatial location catch AND move OR Activity 2 Activity 1 Activity n . . . Pool of Activities 1 n Agent component Activity component Individual Agent Sample CBAF Implementation (RoboCup domain) Activity component(s) • Agent plans are generated as a concatenation of rules rooted by an Activity component • Interface between an agent component and it’s plans • Fully support the agent component capabilities. CSCE 782 – CBAF & SoccerBeans

11. Behavior Components Decision Components kick dash spatial location catch AND move OR Activity 2 Activity 1 Activity n . . . Pool of Activities 1 n Agent component Activity component Individual Agent Sample CBAF Implementation (RoboCup domain) Agent component(s) • Represents an individual agent in the MAS • Knows how to locate and communicate with other agents in the system. • Defines the scheduling mechanism for handling its plans. • A user has to associate the agent component with plans to complete the agent design • Different agent architectures are represented as separate agent components in the framework CSCE 782 – CBAF & SoccerBeans

12. Challenges for CBAF Design • Which components should we develop in the agent framework for a given domain? • The components have to be functionally independent, but they also rely on each other for accomplishing their tasks and hence should be interactive and cohesive. How do we achieve that? • How do we achieve component integration to create new components? • How do we deploy the whole system with multiple agents? CSCE 782 – CBAF & SoccerBeans

13. RoboCup Domain • Simulated soccer • Based on a client/server architecture • Provides an environment that is • Complex • Distributed • Real-time • Collaborative • Adversarial CSCE 782 – CBAF & SoccerBeans

14. Domain Analysis for CBAF Design (SoccerBeans) • Which components should we develop in the agent framework for a given domain? • All agents created as beans, have a scheduling mechanism that supports both BDI and Subsumption architectures • Agent component: PlayerFoundation bean • Only one architecture to be supported • Activity component: Activity bean • Decision criteria in different agent plans for various soccer teams • Decision components: DBallDistance, DSelfPosition, DClosePlayers, etc. • All agent actions • Behavior components: BDash, BDribble, BShoot, BMove, BTurn, etc. CSCE 782 – CBAF & SoccerBeans

15. Domain Analysis for CBAF Design (SoccerBeans) • The components have to be functionally independent, but they also rely on each other for accomplishing their tasks and hence should be interactive and cohesive. How do we achieve that? • Java’s Delegation Event Model for event handling • Communication between adjacent components only • ActivityEvent event • Agent – Activity component communication • FunctionalityEvent event • Activity – Decision component communication • Activity – Behavior component communication • Decision – Behavior component communication CSCE 782 – CBAF & SoccerBeans

16. Domain Analysis for CBAF Design (SoccerBeans) • How do we achieve component integration to create new components? CSCE 782 – CBAF & SoccerBeans

17. Domain Analysis for CBAF Design (SoccerBeans) • How do we deploy the whole system with multiple agents? • Sun’s Bean Development Kit (BDK) provides a runtime environment for deploying live beans • Distributed programming issues handled by UDP sockets • One JVM per agent CSCE 782 – CBAF & SoccerBeans

18. SoccerBeans – CBAF Implementation for RoboCup Domain • Uses the Sun’s JavaBeans technology • Agent component supports decision-making based on BDI and Subsumption architectures • SoccerBeans components - • Agent component • PlayerFoundation bean • Activity component • Activity bean • Decision components • DBallDistance, DBallPosition, DPlayerPosition, etc. • Behavior components • BDash, BKick, BTurn, BMove, etc. CSCE 782 – CBAF & SoccerBeans

19. Agent and Activity Components for SoccerBeans CSCE 782 – CBAF & SoccerBeans

20. Decision Components for SoccerBeans CSCE 782 – CBAF & SoccerBeans

21. Decision Components for SoccerBeans CSCE 782 – CBAF & SoccerBeans

22. Behavior Components for SoccerBeans CSCE 782 – CBAF & SoccerBeans

23. Behavior Components for SoccerBeans CSCE 782 – CBAF & SoccerBeans

24. A Sample Team CSCE 782 – CBAF & SoccerBeans

25. Common Activities • All 11 players share the Observe and StartPlay activities • Observe incorporates the new sensory information from the server into the player’s world model • StartPlay is for relocating the player to its starting position before kickoff and after a goal CSCE 782 – CBAF & SoccerBeans

26. Goalie • Goalie activities • Observe (5) • StartPlay (8) • Catch (10) • Pass (11) • GoalKick (5) • GotoPosition (9) • Used 50 components to create the goalie CSCE 782 – CBAF & SoccerBeans

27. Goalie Activities • Catch activity for allowing the goalie to catch the ball • Pass allows the goalie to move to a corner on the penalty box after catching the ball, or kick the ball away CSCE 782 – CBAF & SoccerBeans

28. Goalie Activities • GoalKick handles the “goal_kick_*” play mode • GotoPosition positions the goalie to the most appropriate position, based on the ball’s current position CSCE 782 – CBAF & SoccerBeans

29. Defenders • Defender activities • Observe (5) • StartPlay (8) • Pass (8) • GotoPosition (25) • Used 47 components to create each defender CSCE 782 – CBAF & SoccerBeans

30. Defender Activities • Defenders simply shoot the ball away towards the opponent’s half whenever possible through the Pass activity • GotoPosition activity CSCE 782 – CBAF & SoccerBeans

31. Defensive Midfielders • Defensive midfielder activities • Observe (5) • StartPlay (8) • Dribble (6) • Pass (9) • GotoPosition (21) • Used 50 components to create each defensive midfielder CSCE 782 – CBAF & SoccerBeans

32. Defensive Midfielder Activities • Midfielders dribble the ball whenever possible • Pass the ball if dribble is inappropriate CSCE 782 – CBAF & SoccerBeans

33. Defensive Midfielder Activities • GotoPosition activity CSCE 782 – CBAF & SoccerBeans

34. Offensive Players • Offensive player activities • Observe (5) • StartPlay (8) • Dribble (7) • Pass (8) • GotoPosition (13,13,11,15,15) • Used an average of 42 components to create each offensive player CSCE 782 – CBAF & SoccerBeans

35. Offensive Player Activities • Dribble activity • Pass activity CSCE 782 – CBAF & SoccerBeans

36. Offensive Midfielder Activities • GotoPosition activity for offensive midfielders CSCE 782 – CBAF & SoccerBeans

37. Offensive Central Midfielder Activities • GotoPosition activity for offensive midfielders CSCE 782 – CBAF & SoccerBeans

38. Forwards’ Activities • GotoPosition activity for forwards CSCE 782 – CBAF & SoccerBeans

39. Testing and Results • Gamecocks beat Chikomalos 18-0! CSCE 782 – CBAF & SoccerBeans

40. Improving SoccerBeans • SoccerBeans has a lot of scope for improvement • Decision beans concerning locations of other agents on the field • Inter-agent communication – “say” messages • Better dashing – use of “turn_neck” instead of “turn” wherever possible • Better kicking – tighter dribbling, better computation of “kick_power” CSCE 782 – CBAF & SoccerBeans

41. Developing New Beans • Beans are just special Java classes! • Implement Serializable class • Define get/set accessor methods for its properties • All decision and behavior beans have similar structures • Differ only in their instance variables and implementations of decide() or behave() methods • Online references: • http://java.sun.com/docs/books/tutorial/javabeans/index.html • http://developer.java.sun.com/developer/onlineTraining/Beans/ CSCE 782 – CBAF & SoccerBeans

42. Developing New Beans in SoccerBeans • Write the bean code • MyBean.java and MyBeanBeanInfo.java files • Save these files in the $PACKAGE_HOME/soccerbeans folder, $PACKAGE_HOME is where the soccerbeans package is extracted • Compile the complete package with the bean • From $PACKAGE_HOME, say javac soccerbeans/*.java regexp/*.java • Update the manifest file • Add the following to the soccerbeans.mft file Name: MyBean.class Java-Bean: True • Update the soccerbeans package • From $PACKAGE_HOME, say jar cfm soccerbeans.jar soccerbeans.mft soccerbeans/*.class regexp/*.class CSCE 782 – CBAF & SoccerBeans