CommonKADS communication model


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Ch. 9 of the CommonKADS textbook

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CommonKADS communication model

  1. 1. Communication Model The Communication Plan Specifying agent-agent transactions Transaction patterns
  2. 2. Communication Model 2 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
  3. 3. Communication Model 3 Relation to other models organiz ation  model tas k  model agent  model knowledge-­‐ intensive task communication model knowledge model des ign model requirements specification for  interaction  functions requirements specification for  reasoning  functions task  selected  in  feasibility  study and  further  detailed  in   Task  and  Agent  Models
  4. 4. Communication Model 4 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.
  5. 5. Communication Model 5 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
  6. 6. Communication Model 6 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?
  7. 7. Communication Model 7 Communication model: overview Task  Model Tas k I/O  info  objects ..... Agent  Model Ag ent capabilities ..... Trans action identifier/name I/O  info  objects agents  involved communication  plan constraints info  exchange  spec Information E xchang e S pecification C ommunication P lan K nowledge  Model Tas k  s tructure transfer  functions ..... involved-­‐in involved-­‐in involved-­‐in part-­‐of part-­‐of dialogue  diagram transaction  control communication  type message  content message  control info  form/medium Focuses on modeling the dialogue between agents" " " Structured, semi- formal approach"
  8. 8. Communication Model 8 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
  9. 9. Communication Model 9 Sample application ■  Energy market ➤  dynamic pricing of energy ➤  enables companies to do load management ➤  HOMEBOTS: intelligent electrical agents ➤  requires two-way communication system utilityutility customercustomer utilityutility customercustomer kWh & kWh info
  10. 10. Communication Model 10 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
  11. 11. Communication Model 11 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
  12. 12. Communication Model 12 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
  13. 13. Communication Model 13 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
  14. 14. Communication Model 14 Dialogue Diagram: general structure Task  A2 Task  A3 Task  A4 Task  B 2 Task  A5 A g ent  A (e.g .    us er) Task  B 3 A g ent  B (e.g .  s ys tem ) Task  B 4 Task  A1 D ialog ue Transac tion Tr.  1 Transac tion Tr.  2 Transac tion Tr.  3 Task  B 1 Transac tion Tr.  4 Note: agent's (leaf) tasks are key entry to dialogue diagram construction"
  15. 15. Communication Model 15 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
  16. 16. Communication Model 16 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" Announce E xpress P references B id Assess Award S chedule Implement Monitor Monitor C O M M U N I C A T E Utility C us tomer
  17. 17. Communication Model 17 CP for the housing application application assessment waiting  for   case  data application  received/ order  assessment data  needed/ask data  received  /  reply assessment  finished/ report  decision
  18. 18. Communication Model 18 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)
  19. 19. Communication Model 19 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)
  20. 20. Communication Model 20 Homebots Dialogue Control R eduction  need? Auction Running Announce  &  Kick-­‐off Assess Interested?  N Interested?  Y Opt  out E xpress  Prefs. Opted  Out Preferences C alculated Bids  received? Power  need? Bid  &  S ubmit Bid S ubmitted Convergence?  N Convergence?  Y Award  &  Present Next  R ound Auction  C ompleted/ Awards  Distributed Allocation C omputed
  21. 21. Communication Model 21 Communication Model: Middle Level Specification of individual transactions, structured in a number of components:" " " Simple worksheet techniques are helpful here" T R ANS -­‐ AC T ION identifier &  name agents involved communication plan information objects information  exchange specification constraints
  22. 22. Communication Model 22 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
  23. 23. Communication Model 23 Transaction “Housing” (1) Transaction name Order application assessment Information object a residence application Agents involved data entry + knowledge system (+ assigner) Comm. Plan active when application arrives. Constraints Prototyping: interact with user Informtation exchange ransaction is of the “order” type
  24. 24. Communication Model 24 Transaction “Housing” (2) Transaction name Obtain application data Information object Attribute-value pairs of an a applicant and residence Agents involved database + knowledge system Comm. Plan transitions connected to the “waiting for data” state Constraints Ensure mapping of data request onto DB data format Informtation exchange transaction is of the ask-reply type.
  25. 25. Communication Model 25 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!"
  26. 26. Communication Model 26 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?
  27. 27. Communication Model 27 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)
  28. 28. Communication Model 28 Communication types Task delegation Task adoption Information exchange Request Propose Ask Require Offer Reply Order Agree Report Reject-td Reject-ta Inform
  29. 29. Communication Model 29 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.
  30. 30. Communication Model 30 Typed Message Patterns INF ORM AS K C ommunic ation  type  patterns 1) 2) RE P LY 3) ORDE R RE P ORT AGRE E RE P ORT 4) AGRE E 5) RE QUIRE RE J E C T-­‐ta ORDE R 6) OF F E R RE J E C T-­‐td P ROP OS E 7) RE QUE S T OF F E R RE J E C T-­‐ta RE QUE S T 8) P ROP OS E RE QUIRE RE J E C T-­‐td Not only typing of single messages possible. " Also, natural chains of message types can be formed (cf. COSY):" Communication Patterns "
  31. 31. Communication Model 31 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
  32. 32. Communication Model 32 Transaction “submit-the-bid”: message specifications ■  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
  33. 33. Communication Model 33 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
  34. 34. Communication Model 34 Control over messages ■  Refinement of control in communication plan ■  Notations: the same ➤  State diagram ➤  Pseudo code
  35. 35. Communication Model 35 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
  36. 36. Communication Model 36 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
  37. 37. Communication Model 37 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 ■  …..
  38. 38. Communication Model 38 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
  39. 39. Communication Model 39 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