Design Patterns & Component Frameworks CS67041Spring 2002 Open Agent Architecture (OAA) - Part II -Murali Krishnan

Design Patterns & Component Frameworks CS67042Spring 2002 Interagent Communication Language (ICL) Interface, communication & task coordination language shared by all agents Used by agents to perform queries, execute actions, exchange information, set triggers & manipulate data Includes a conversational layer protocol (events, parameters) & content layer (goals, triggers & data elements) ICL – Unified way of expressing agent functionalities! -Register capability specifications -Request services of agents in community PROLOG is used!

Design Patterns & Component Frameworks CS67043Spring 2002 ICL contd… Platform independent – supports C, C++, VB, Delphi, Java, Prolog, LISP Interagent communication – through events & message passing –ev_post_solve (Goals, Params) ->typical event Agents use ICL to define and publish their capabilities and services provided, to the facilitator Agents capabilities declarations - SOLVABLES

Design Patterns & Component Frameworks CS67044Spring 2002 Solvables: Data solvablesProcedure solvables -perform a test or action -must have a handler declared and defined -Provides access to collection of data -associated with dynamic collection of facts Specification of solvables: solvable ( Goal, Parameters, Permissions ) Examples: solvable (send_message ( , +ToPerson, +Params), [type(procedure), callback (send_mail)], [] ) solvable (last_message ( , -MessageId), [type(data), single_value(true)], [write(true)] )

Design Patterns & Component Frameworks CS67045Spring 2002 Agent library: Provides infrastructure for building new agent-based system Single, unified point of entry for requesting services – library procedure oaa_Solve() Contains many other procedures like: –oaa_declare, oaa_undeclare, oaa_redeclare – regn. with facilitator –oaa_adddata, oaa_removedata, oaa_replacedata – updates to data solvables –oaa_addtrigger, oaa_removetrigger, oaa_replacetrigger – procedures for trigger-related operations Inter-agent and Intra-agent communication

Design Patterns & Component Frameworks CS67046Spring 2002 OAA Triggers: Action fired, when condition met Types: communication, data, task & time When trigger fires, execution of action is delegated to the facilitator oaa_AddTrigger(Type, conditions, action, params) Communication triggers: monitor incoming / outgoing events Data triggers: monitor the state of a data repository Task triggers: test arbitrary conditions after processing event or timeout Time triggers: monitor time related conditions

Design Patterns & Component Frameworks CS67047Spring 2002 Multimodal User Interfaces: User is special member of agent community Agents compete to recognize and act on user actions Natural Language (NL) translation to & from ICL Multiagent cooperation for ambiguity resolution Pen: gesture or handwriting? Reference resolution: “photo of the hotel” - NL Agent: hotel in language context - Gesture Agent: hotel being pointed at - UI Agent: only one hotel visible - Database Agent: “hotel on Smith Street” - Discourse Agent: “the other hotel” -Human User: if still ambiguous, can clarify Cross-modality ambiguities

Design Patterns & Component Frameworks CS67048Spring 2002 Multimodal map --- Example OAA application: Sample Interaction: 2.1 [Speaking] Where is downtown? Map scrolls to appropriate area. 2.2 [Speaking and drawing region] Show me all hotels near here. Icons representing hotels appear. 2.3 [Writes on a hotel] Info? A textual description (price, attributes, etc.) appears. 2.4 [Speaking] I only want hotels with a pool. Some hotels disappear. and so on… Natural interface to distributed (web) data Synergistic combination of handwriting, drawing, speech, direct manipulation

Design Patterns & Component Frameworks CS67049Spring 2002 OAA and Scalability Current Limitations:Facilitator is single point of failure Facilitator is bottleneck for communication Facilitator Multi-Facilitator topologies Distribution of planning & execution functions of Facilitator + peer-to-peer communication Registry & Planner Agent E Replicated Plan + Exe Facilitator Possible Solutions: CMM2

Design Patterns & Component Frameworks CS670410Spring 2002 OAA Characteristics: agents can be created in many languages and interface with existing systems agents can be added or replaced dynamically agents are spread across many computers Parallel execution of subtasks Lightweight interfaces on phone and/or PDA hides software and hardware dependencies handwriting, speech, gestures, and direct manipulation can be combined together Open: Extensible: Distributed: Parallel: Mobile: High-level: Multimodal: CMM2

Design Patterns & Component Frameworks CS670411Spring 2002 References: [CMM1] The Open Agent Architecture: A Framework for Building Distributed Software Systems – David L.Martin, Adam J. Cheyer, Douglas B. Moran, (AI center, SRI International) (Technical paper) [CMM2] The Open Agent Architecture, by the same authors. (PowerPoint presentation) Open Agent Architecture: Technical white paper. See website An Open Agent Architecture, Philip Cohen, Adam Cheyer, Michelle Wang, Soon Cheol Baeg. ( See website