Christopher Newport University Using a Performative Subsumption Lattice

Christopher Newport University 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 2005/07/27 Roberto Flores Christopher Newport University Department of Physics, Computer Science and Engineering Newport News, VA flores@pcs. cnu. edu Commitment-based Conversations 1

Christopher Newport University Message Format • Envelope – Can be understood by all agents – Tag/value pairs – CASA can use KQML (next slide) or XML syntax • Content – Might only be understood by specific agent – The language tag specifies the format of the content 2005/07/27 Commitment-based Conversations 2

Christopher Newport University Message Format: Envelope : performative : act : to : from : sender : receiver : in-reply-to : reply-with : conversation-id : language-version : content : version : ontology : timeout 2005/07/27 performative act URL URL string string content version-spec ontology-spec time Commitment-based Conversations 3

Christopher Newport University Message Format: XML DDT <!DOCTYPE CASAmessage [ <!ELEMENT CASAmessage (version, performative, act? , sender, receiver, from? , to? , timeout? , reply-with? , in-reply-to? , language-version? , ontology-version? , content? )> <!ELEMENT version (#PCDATA)> <!ELEMENT performative (#PCDATA)> <!ELEMENT act (#PCDATA)> <!ELEMENT sender (#PCDATA)> <!ELEMENT receiver (#PCDATA)> <!ELEMENT from (#PCDATA)> <!ELEMENT to (#PCDATA)> <!ELEMENT timeout (#PCDATA)> <!ELEMENT reply-with (#PCDATA)> <!ELEMENT in-reply-to (#PCDATA)> <!ELEMENT language-version (#PCDATA)> <!ELEMENT ontology-version (#PCDATA)> <!ELEMENT content ANY > ]> 2005/07/27 Commitment-based Conversations 4

Christopher Newport University Message Format: Example : performative request : act invite. To. Join. CD : to casa: //123. 181. 6. 101/Bob : from casa: //123. 181. 6. 65/Alice : receiver casa: //123. 181. 6. 101/CDagent 1 : sender casa: //123. 181. 6. 65/Alice : reply-with casa: //123. 181. 6. 65/Alice$$1453 : language casa. URL : language-version 1. 0 : content casa: //123. 181. 6. 101/CDagent 2 2005/07/27 Commitment-based Conversations 5

Christopher Newport University FIPA Performatives inform proxy propagate request cancel confirm disconfirm inform-ref query-if request-when propose query-ref call-for-participation request-whenever subscribe 2005/07/27 agree accept-proposal failure not-understood reject-proposal refuse Commitment-based Conversations 6

Christopher Newport University FIPA Performatives performative inform Added catagories proxy propagate ack reply request cancel reply-propose-discharge affirmative-reply confirm disconfirm inform-ref query-if request-when propose query-ref call-for-participation request-whenever subscribe 2005/07/27 agree accept-proposal negative-reply failure not-understood reject-proposal refuse Commitment-based Conversations 7

Christopher Newport University FIPA Performatives performative inform Added catagories Arranged in a lattice proxy propagate ack reply request cancel reply-propose-discharge affirmative-reply confirm disconfirm inform-ref query-if request-when propose query-ref call-for-participation request-whenever subscribe 2005/07/27 agree accept-proposal negative-reply failure not-understood reject-proposal refuse Commitment-based Conversations 8

Christopher Newport University FIPA Performatives performative inform proxy propagate ack Added catagories Arranged in a lattice Extended reply request cancel reply-propose-discharge affirmative-reply propose-discharge nack confirm disconfirm done inform-ref query-if request-when propose query-ref call-for-participation request-whenever subscribe 2005/07/27 agree notify accept-proposal negative-reply timeout failure not-understood reject-proposal refuse Commitment-based Conversations 9

Christopher Newport University Policies P-inform commits the addressee to acknowledge P-ack releases informed agents of the commitment to acknowledge P-request commits the proposed agents to reply P-counteroffer commits addressees to reply P-reply releases proposed agents of the commitment to reply and releases counteroffered agents of the commitment to reply P-agree an acceptance realizes the shared uptake of proposed/counteroffered commitments P-done releases accepted agents of the commitment earlier agreed to 2005/07/27 Commitment-based Conversations 10

Christopher Newport University Policies Commitment Operators Performatives Policies Performative P-inform P-ack Inform Ack P-request Reply P-reply Agree P-agree Confirm P-confirm 2005/07/27 Commitment Operators Commitment-operator Operator: add Commitment: (receiver, sender, ack) Commitment-operator Operator: delete Commitment: (sender, receiver, ack) Social Commitments action communication-act Commitment-operator Operator: add Commitment: (reciever, sender, reply) ack Commitment-operator Operator: delete Commitment: (receiver, sender, reply) reply Commitment-operator Operator: add Commitment: (receiver, sender, content) Commitment-operator Operator: delete Commitment: (receiver, sender, content) Commitment-based Conversations Unspecified action 11

Christopher Newport University Example: Informally Alice Can you attend this meeting? (nod) Bob (performative: request, content: attend(Bob, x)) (performative: agree, content: attend(Bob, x)) Sure. . . (performative: ack, content: attend(Bob, x)) I’m here (nod) (performative: inform, content: attend(Bob, x)) (performative: ack, content: attend(Bob, x)) Thanks for coming. (performative: confirm, content: attend(Bob, x)) (nod) (performative: ack, content: attend(Bob, x)) 2005/07/27 Commitment-based Conversations 12

Christopher Newport University Example: Perf. Lattice and Commitments Bob Alice ack(Alice, Bob, x) inform ack(Bob, Alice, x) request ack reply(Bob, Alice, x) inform ack reply agree ack(Alice, Bob, x) act(Bob, Alice, x) inform ack reply-propose-discharge(Alice, Bob, x) propose-discharge(Bob, Alice, x) done ack inform ack(Bob, Alice, x) reply-propose-discharge confirm ack 2005/07/27 Commitment-based Conversations 13

Christopher Newport University Example: Implementation Details Bob Alice inform request ack consider(Alice, Bob, x) inform ack(Alice, Bob, x) reply(Bob, Alice, x) ack reply agree ack evaluate(Alice, Bob, x) ack(Alice, Bob, x) reply-propose-discharge(Alice, Bob, x) decide(Bob, Alice, x)` ack(Bob, Alice, x) act(Bob, Alice, x) inform ack reply propose-discharge(Bob, Alice, x) done ack inform reply accept(Bob, Alice, x) ack(Bob, Alice, x) reply-propose-discharge confirm ack 2005/07/27 Commitment-based Conversations 14

Christopher Newport University 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 2005/07/27 Commitment-based Conversations 15