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Communication Model. The Communication Plan Specifying agent-agent transactions Transaction patterns. Role of Communication Model. specifies knowledge/information transfer procedures top-level control over task execution multiple knowledge-intensive tasks additional communication tasks

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Communication model l.jpg

Communication Model

The Communication Plan

Specifying agent-agent transactions

Transaction patterns


Role of communication model l.jpg
Role of Communication Model

  • specifies knowledge/information transfer procedures

  • top-level control over task execution

    • multiple knowledge-intensive tasks

  • additional communication tasks

    • explanation facilities

  • example: basic system-user interaction



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Input for communication modeling

  • Task Model

    • list of leaf tasks carried out by the considered agents

  • Knowledge Model

    • transfer functions

  • Agent Model

    • description of relevant agents: capabilities, responsibilities constraints.


Information systems communication l.jpg
Information systems:communication

More and more, IS are becoming information + communication systems:

  • distributed applications (telematics)

  • virtual organizations

  • CSCW

  • intelligent multi-agent systems

  • workflow management

  • concurrent engineering

  • business chain management and integration


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Communication between actors

  • Information modeling must cover:

    • Organizational/Business analysis

    • Task/Workplace analysis

    • Actor/Agent analysis (both human and system)

  • Usually, several actors cooperate in a business process or task, so

    • Communication model intends to capture agent interactions within a joint task

  • Communication Model = conceptual specification of:

    what kind of information objects are exchanged between agents in cooperating in and carrying out a task, and how?


  • Communication model overview l.jpg
    Communication model:overview

    Focuses on modeling the dialogue between agents

    Structured, semi-formal approach


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    Communication Model:overview

    • Layered approach to Communication Modeling

    • Three levels:

      • 1. The overall communication plan, which governs the full dialogue between two agents

      • 2. The individual transactions that link two (leaf) tasks carried out by two different agents

      • 3. The information exchange specification that details the internal message structure of a transaction

    • Start to construct the global overview, and fill in the details later


    Sample application l.jpg
    Sample application

    • Energy market

      • dynamic pricing of energy

      • enables companies to do load management

      • HOMEBOTS: intelligent electrical agents

      • requires two-way communication system


    Transaction l.jpg
    Transaction

    • key component of Communication Model

    • describes what information objects are exchanged

    • indicates agents and tasks involved

    • go-between of two tasks carried out by different agents

    • building blocks for the full dialogue between two agents

    • transactions have an internal structure

      • example: obtain


    Other cm concepts l.jpg
    Other CM concepts

    • Communication plan

      • governs the full dialogue between the agents

      • organization of transactions

    • Information exchange specification

      • details transaction structure

      • consists of messages

      • only necessary for complex communications


    Communication plan l.jpg
    Communication Plan

    • easiest to begin with the overall communication plan

    • describes full top-level dialogue

    • typical transactions

      • data input

      • asking or answering questions

      • presentation of reasoning results

      • explanation of results


    Communication plan activities l.jpg
    Communication plan activities

    • for each agent: list all tasks

    • for each task: identify set of associated agent-agent transactions

    • results combined in “dialogue diagram"

      • DD depicts transactions between two agents

    • draw a DD for each combination of two agents that exchange a reasonable amount of information

    • specify control over the transactions


    Dialogue diagram general structure l.jpg
    Dialogue Diagram: general structure

    Note: agent's (leaf) tasks are key entry to dialogue diagram construction


    New customer services ict technology l.jpg
    New Customer Services:ICT Technology

    • Through networked microprocessors, devices can 'talk to', 'negotiate', 'make decisions', and 'cooperate' with one another.

      • Smart equipment agents we call homebots (inspired by Star Trek and Asimow's Robot Stories)

  • We use this,e.g., for distributed power load management (Further info: see separate case)

  • Benefits:

    • handles much larger scale

    • higher degree of automation & decentralized flexible approach

    • proactive for the customer


  • Dd for energy market l.jpg
    DD for energy market

    Task and transaction links in power auction are graphically sketched in the dialogue diagram:

    Gives overview of the system's communication plan



    Transactions in the homebots system l.jpg
    Transactions in the Homebots System

    • Transaction list:

      • 1. Kick-off the auction: sends a trigger signal to the customer agents to commence a load management action

      • 2. Submit the bids: transmits the bids from the customer agents to the auctioneer for further processing

      • 3. Present the awarded power allocation: informs the customer agents about the results of the auction

      • 4. Present the associated real-time schedule: provides the customer agents with the calculated schedule that implements the awarded allocation

      • 5. Receive the resulting real-time implementation data: transmits the actual metering data (Needed for billing and for assessing the need for further load management actions)


    Transaction control notations l.jpg
    Transaction control notations

    • state diagrams

    • pseudo-code with special control primitives

      SEND, RECEIVE

      CARRY-OUT (SEND/RECEIVE combination)

      WAIT-until/while

      PROCESS (task)

      ; (sequence)

      REPEAT-until/while, IF THEN ELSE

      & (AND), | (choice), V (OR)



    Communication model middle level l.jpg
    Communication Model:Middle Level

    Specification of individual transactions, structured in a number of components:

    Simple worksheet techniques are helpful here


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    Illustration Middle Level:Homebots System (II)

    • Submit-the-bid transaction description (Worksheet CM-1)

      • Identifier/Name: Transaction 2: Submit-the-bid

      • Information objects: linking Bid and Assess tasks: (1) bid; (2) going price or going allocation (depending on domain theory)

      • Agents involved: (1) customer agents; (2) auctioneer/utility agent

      • Communication plan: Homebots (base version)

      • Constraints: (1) decision procedure for bidding completeness; (2) market convergence postcondition

      • Information Exchange Spec: See Worksheet CM-2

  • Note: this transaction contains more than one message, and so is composite




  • Composite transactions l.jpg
    Composite Transactions

    • "I'm getting cold, so could you please shut the door?''

      • First part is just information: notification message

      • Second part is request for action by the other agent: task delegation message

    • So, within one transaction: two messages differring in both content and intent

  • Transactions not only transmit content, but also an intended relationship between two agents. Both these aspects must be explicitly specified.

    • Compare: "Hey, idiot, shut the door, I'm getting cold!"


  • Speech acts l.jpg
    Speech Acts

    • Agent communication languages often inspired by so-called speech act theory

    • Makes distinctions between:

      • Content ('locutionary nature') of a speech act or message -- what is actually being said --

      • Intended effect ('illocutionary force') on the other agent

      • Actual effect ('perlocutionary force') on the other agent

        • N.B. nice communication modeling exercises:

          • "It's the economy, stupid!''

          • Edward Albee's Who's Afraid of Virginia Woolf?


    Communication model detail level l.jpg
    Communication Model:Detail Level

    • Detailed message specification:

      • 1. Content (locution): by means of a propositional statement

      • 2. Intention (illocution): by means of typing a message

    • Predefined types:

      • Task Delegation: Request; Require; Order; Reject-td

      • Task Adoption: Propose; Offer; Agree; Reject-ta

      • Pure Information Exchange: Ask; Reply; Report; Inform

  • Note: Intention = purpose x commitment

    • Cf. performatives in KQML (DARPA Knowledge Sharing Effort) and esp. COSY (Daimler-Benz)



  • Semantics of communication types l.jpg
    Semantics of Communication Types

    • Request/Propose: potential for cooperation, but agent wishes to negotiate on the terms. Loosely: `I have an interest, but not yet a commitment'.

    • Require/Offer: agent already has made a pre-commitment, and intends to prompt the receiving agent for its commitment. This type thus denotes a conditional commitment.

    • Order/Agree: agent has made a commitment, and thus will act accordingly.

    • Reject-td/ta: denote that the agent does not want to commit or cooperate.

    • Ask/Reply: have as intent a query for information from another agent, and delivery of information in return.

    • Report: types a message sent after an agent has acted towards a (previously) agreed task goal, with the intention to let the other agent know the status of achievement (e.g. success, failure, outcome of the action).

    • Inform: refers to a message type that just delivers information objects to another agent. Indicates an independent informative action: no previous request or agreement involved.


    Typed message patterns l.jpg
    Typed Message Patterns

    Not only typing of single messages possible.

    Also, natural chains of message types can be formed (cf. COSY):

    Communication Patterns


    Worksheet cm 2 information exchange specification l.jpg
    Worksheet CM-2: Information Exchange Specification

    • Only needed for complex communication patterns

      • energy market

    • Worksheet structure

      • Transaction Identifier/Name

      • Agents involved: sender, receiver

      • Information items

      • Message specification

      • Message control


    Transaction submit the bid message specifications l.jpg

    Bid-message

    type:PROPOSE

    content: bid

    from: customer agent

    to: auctioneer

    Opt-out-message

    type: REJECT-TA

    content: no part

    from: customer agent

    to: auctioneer

    Auction-data-message

    type: INFORM

    content: market data

    from: auctioneer

    to: customer agent

    Next-round-message

    type: REQUEST

    content: trigger next round

    from: auctioneer

    to: customer agent

    Transaction “submit-the-bid”:message specifications


    Information items l.jpg
    Information items

    • role:

      • core object

      • support item

        • explanation texts of domain material

          • rock photographs, mineral photographs

        • reasoning traces

        • WHY/HOW explanations

    • syntactic form: data string, diagram, ...

    • medium: pop-up window, command-line interface, human intervention, …

      • cf. Design issues


    Control over messages l.jpg
    Control over messages

    • Refinement of control in communication plan

    • Notations: the same

      • State diagram

      • Pseudo code


    Transaction submit the bid l.jpg
    Transaction: submit-the-bid

    REPEAT WHILE <market convergence condition not satisfied>

    IF <interest in load management>

    THEN PROCESS(bid-task); SEND(BID-MESSAGE)

    ELSE SEND(OPT-OUT-MESSAGE)

    END-IF

    IF <bids received>

    THEN PROCESS(assess-task)

    ELSE PROCESS(decision subprocedure [e.g. WAIT...])

    END-IF

    SEND(AUCTION-DATA-MESSAGE) &

    SEND(NEXT-ROUND-MESSAGE)

    END-REPEAT


    Validation techniques l.jpg
    Validation techniques

    • Communication-plan walk-through

      • adequacy transaction structure

      • completeness list of information items

      • need for help or explanation

    • Wizard-of-Oz technique

      • experimental technique to validate interaction

      • mock-up software


    Nielsen s guidelines for usability engineering l.jpg
    Nielsen's guidelines for usability engineering

    • Present a simple and natural dialogue

    • Speak the user's language

    • Minimize the user's memory load

    • Maintain consistency in terminology

    • Give feedback about what is going on

    • Show clearly marked exits from unwanted states

    • Offer shortcuts for the experienced user

    • …..


    Guidelines for balancing the communication model l.jpg
    Guidelines for balancing the communication model

    • Key inputs:

      • leaf tasks TM

      • transfer function KM

    • Take agent capabilities into account (see AM)

    • syntactic form of media is area of both CM and DM

      • guideline: in CM if conceptual reason

    • Decide here about support information

      • not in design model


    Communication model activities l.jpg
    Communication model activities

    • Identify core information objects to be exchanged between agents

    • Identify associated transactions

    • Draw important dialogue diagrams

    • Combine this to a full communication plan

    • Specify the individual transactions

      • worksheets CM-1 and CM-2

    • Validate and balance the model


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