communication model the communication plan specifying agent-agent transactions transaction patterns
TRANSCRIPT
Communication Model
The Communication Plan
Specifying agent-agent transactions
Transaction patterns
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
Communication Model 3
Relation to other models
organization modeltask model
agent model
knowledge-intensive
task
communicationmodel
knowledgemodel
designmodel
requirementsspecification
for interaction functions
requirementsspecification
for reasoning functions
task selected in feasibility studyand further detailed in
Task and Agent Models
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.
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
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?
Communication Model 7
Communication model:overview
Task Model
Task
I/O info objects.....
Agent Model
Agent
capabilities.....
Transaction
identifier/nameI/O info objectsagents involved
communication planconstraints
info exchange spec
InformationExchange
Specification
CommunicationPlan
Knowledge Model
Task structure
transfer functions.....
involved-in involved-in
involved-in
part-of part-of
dialogue diagramtransaction control
communication typemessage contentmessage controlinfo form/medium
Focuses on modeling the dialogue between agents
Structured, semi-formal approach
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
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 customercustomerkWh
&
kWh
info
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
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
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
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
Communication Model 14
Dialogue Diagram: general structure
Task A2
Task A3
Task A4
Task B2
Task A5
Agent A(e.g. user)
Task B3
Agent B(e.g. system)
Task B4
Task A1
Dialogue
TransactionTr. 1
TransactionTr. 2
TransactionTr. 3
Task B1
TransactionTr. 4
Note: agent's (leaf) tasks are key entry to dialogue diagram construction
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
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
AnnounceExpress
Preferences
Bid
Assess
Award
Schedule
Implement
Monitor Monitor
COMMUNICATE
Utility Customer
Communication Model 17
CP for the housing application
applicationassessment
waiting for case data
application received/order assessment
data needed/ask
data received / reply
assessment finished/report decision
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)
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)
Communication Model 20
Homebots Dialogue Control
Reduction need?
AuctionRunning
Announce & Kick-off
Assess
Interested? N Interested? YOpt out Express Prefs.
Opted OutPreferencesCalculated
Bids received?
Power need?Bid & Submit
BidSubmitted
Convergence? NConvergence? Y
Award & PresentNext Round
Auction Completed/Awards Distributed
AllocationComputed
Communication Model 21
Communication Model:Middle Level
Specification of individual transactions, structured in a number of components:
Simple worksheet techniques are helpful here
TRANS-ACTION
identifier& name
agentsinvolved
communicationplan
informationobjects
information exchangespecification
constraints
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
Communication Model 23
Transaction “Housing” (1)
Transaction name Order application assessment
I nformation object a residence application
Agents involved data entry + knowledge system(+ assigner)
Comm. Plan active when application arrives.
Constraints Prototyping: interact with user
I nformtation exchange ransaction is of the “order”type
Communication Model 24
Transaction “Housing” (2)
Transaction name Obtain application data
I nformation object Attribute-value pairs of an aapplicant and residence
Agents involved database + knowledge system
Comm. Plan transitions connected to the“waiting f or data” state
Constraints Ensure mapping of datarequest onto DB data f ormat
I nformtation exchange transaction is of the ask-replytype.
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!"
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?
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)
Communication Model 28
Communication types
Task delegation Task adoption Informationexchange
Request Propose Ask
Require Offer Reply
Order Agree Report
Reject-td Reject-ta Inform
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.
Communication Model 30
Typed Message Patterns
INFORM
ASK
Communication type patterns
1)
2)
REPLY
3)
ORDER
REPORT
AGREE
REPORT
4)
AGREE
5)
REQUIRE
REJ ECT-ta
ORDER
6)
OFFER
REJ ECT-td
PROPOSE
7)
REQUEST
OFFER REJ ECT-ta
REQUEST
8)
PROPOSE
REQUIRE REJ ECT-td
Not only typing of single messages possible. Also, natural chains of message types can be formed (cf. COSY):
Communication Patterns
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
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
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
Communication Model 34
Control over messages
Refinement of control in communication plan Notations: the same
State diagram Pseudo code
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
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
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 …..
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
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