1. Christopher Newport University 2005/07/27Commitment-based Conversations 1 Using a Performative Subsumption Lattice to Support Commitment-based Conversations Rob Kremer University of Calgary Department of Computer Science Calgary, CANADA kremer@cpsc.ucalgary.ca Roberto Flores Christopher Newport University Department of Physics, Computer Science and Engineering Newport News, VA flores@pcs.cnu.edu

2. Christopher Newport University 2005/07/27Commitment-based Conversations2 FIPA Performatives inform cancelrequest query-refcall-for-participation inform-refquery-ifrequest-when request-whenever propose agree subscribe confirm failurenot-understoodreject-proposalrefuse disconfirm accept-proposal proxypropagate

3. Christopher Newport University 2005/07/27Commitment-based Conversations3 FIPA Performatives inform cancelrequest query-refcall-for-participation inform-refquery-ifrequest-when request-whenever propose agree subscribe confirm failurenot-understoodreject-proposalrefuse disconfirm accept-proposal proxypropagate performative ack affirmative-reply reply negative-reply reply-propose-discharge Added catagories

4. Christopher Newport University 2005/07/27Commitment-based Conversations4 FIPA Performatives inform cancelrequest query-refcall-for-participation inform-refquery-ifrequest-when request-whenever propose agree subscribe confirm failurenot-understoodreject-proposalrefuse disconfirm accept-proposal proxypropagate Arranged in a lattice performative ack affirmative-reply reply negative-reply reply-propose-discharge Added catagories

5. Christopher Newport University 2005/07/27Commitment-based Conversations5 Extended FIPA Performatives inform cancelrequest query-refcall-for-participation inform-refquery-ifrequest-when request-whenever propose notifyagree subscribe nack confirm timeoutfailurenot-understoodreject-proposalrefuse disconfirm accept-proposal proxypropagate propose-discharge done Arranged in a lattice performative ack affirmative-reply reply negative-reply reply-propose-discharge Added catagories

6. Christopher Newport University 2005/07/27Commitment-based Conversations6 Policies P-informcommits the addressee to acknowledge P-ackreleases informed agents of the commitment to acknowledge P-requestcommits the proposed agents to reply P-counteroffercommits addressees to reply P-replyreleases proposed agents of the commitment to reply and releases counteroffered agents of the commitment to reply P-agreean acceptance realizes the shared uptake of proposed/counteroffered commitments P-donereleases accepted agents of the commitment earlier agreed to

7. Christopher Newport University 2005/07/27Commitment-based Conversations7 Policies  Commitment Operators Performative Ack Reply Inform Request Agree Confirm Performatives Commitment-operator Operator: add Commitment: (receiver,sender,ack) Commitment-operator Operator: delete Commitment: (receiver,sender,reply) Commitment-operator Operator: delete Commitment: (sender,receiver,ack) Commitment-operator Operator: add Commitment: (reciever,sender,reply) Commitment-operator Operator: add Commitment: (receiver,sender,content) P-inform P-ack P-request P-reply P-agree Commitment-operator Operator: delete Commitment: (receiver,sender,content) P-confirm PoliciesCommitment Operators action reply ack communication-act Unspecified action Social Commitments

8. Christopher Newport University 2005/07/27Commitment-based Conversations8 Example: Informally Alice Bob (performative: request, content: attend(Bob,x)) Can you attend this meeting? (performative: agree, content: request|attend(Bob,x)) Sure... (performative: propose, content: discharge|attend(Bob,x)) I’m here (performative: accept-proposal, content: discharge|attend(Bob,x)) Thanks for coming. (performative: ack, content: agree|request|attend(Bob,x)) (nod) (performative: ack, content: accept-proposal|discharge|attend(Bob,x)) (nod) (performative: ack, content: discharge|attend(Bob,x)) (nod)

9. Christopher Newport University 2005/07/27Commitment-based Conversations9 Example: Perf. Lattice and Commitments reply-propose-discharge(Alice,Bob,x) act(Bob,Alice,x) propose-discharge(Bob,Alice,x) Alice Bob request inform reply agree informack propose/discharge reply informack agree accept-proposal reply informack reply(Bob,Alice,x) ack(Bob,Alice,x) ack ack(Bob,Alice,x) ack ack(Alice,Bob,x) ack ack(Alice,Bob,x) ack

10. Christopher Newport University 2005/07/27Commitment-based Conversations10 Example: Implementation Details reply(Bob,Alice,x) act(Bob,Alice,x) reply-propose-discharge(Alice,Bob,x) propose-discharge(Bob,Alice,x) Alice Bob reply request/* agree/request|* propose/discharge|* agree accept-proposal/propose/discharge|* reply inform evaluate(Alice,Bob,x) decide(Bob,Alice,x)` consider(Alice,Bob,x) accept(Bob,Alice,x) inform ack ack(Bob,Alice,x) ack ack(Bob,Alice,x) ack ack(Alice,Bob,x) ack ack(Alice,Bob,x) ack

11. Christopher Newport University 2005/07/27Commitment-based Conversations11 Conclusions Arranging performatives in a lattice simplifies interpretation Messages (performatives) → policies → commitment operators → shared social commitments Easily observable by 3 rd parties Agents do not have the be implemented in the SC style (eg. could be BDI internally) Turn taking arrises naturally