Information, action and negotiation in dialogue systems Staffan Larsson Kings College, Jan 2001

Overview dialogue modelling the information state approach & TrindiKit GoDiS – a dialogue system action- and information oriented dialogue negotiative dialogue

Dialogue modelling Theoretical motivations –find structure of dialogue –explain structure –relate dialogue structure to informational and intentional structure Practical motivations –build dialogue systems to enable natural human-computer interaction –speech-to-speech translation –...

Informal approaches to dialogue modelling speech act theory (Austin, Searle,...) –utterances are actions –illocutionary acts: ask, assert, instruct etc. discourse analysis (Schegloff, Sacks,...) –turn-taking, pre-sequences etc. dialogue games (Sinclair & Coulthard,...) –structure of dialogue segments (rather than separate utterances) –can e.g. be encoded as regular expressions or finite automata qna-game -> question qna-game* answer

Computational approaches implemented in systems and toolkits finite state automata (CLSU toolkit, Nuance) frame-based (Philips, SpeechWorks) plan-based (TRAINS, Allen, Cohen, Grosz, Sidner,...) general reasoning (Sadek,...) information states (TRINDI: Traum, Bos,...)

Inquiry- vs. action-oriented dialogue Inquiry oriented dialogue (IOD) has the primary goal of exchanging information –regardless of whether and how this information will be used in future actions Action oriented dialogue (AOD) has the primary goal of a participant performing or being obliged to perform an action (or plan, i.e. a complex action)

Inquiry-oriented dialogue utterance types: ask, answer Information-seeking dialogue: one DP asks the questions, the other answers them Information-exchange (information oriented) dialogue: both DPs ask questions and provide answers – can be seen as a sequence of infoseeking dialogues, possibly with embedded subdialogues

Action-oriented dialogue utterance types: request, confirm In simple AOD, only one participant becomes obliged/comitted to some action or plan Actions can either be performed ”online” while the dialogue is happening, or they may be stored as a plan to be performed after the dialogue (”offline”)

Negotiative dialogue utterance types: suggest, accept, reject What is it? –Negotiation is a type of problem-solving –Possible definition of negotiative dialogue: DPs discuss several alternative solutions to a problem before choosing one of them Negotiation does not imply conflicting goals –perhaps not 100% correspondence to everyday use of the word “negotiation”, but useful to keep collaborativity as a separate dimension from negotiation Both AOD and IOD can be negotiative –in a flight information service, the user does not become obliged to fly anywhere; so it’s IOD –but several different flights may be discussed

Negotiation tasks Some factors influencing negotiation –distribution of information between DPs (who knows what) –whether DPs must commit jointly (e.g. Coconut) or one DP can make the comittment (e.g. flight booking) We’re initially trying to model negotiation in flight booking –sample dialouge U: flights to paris on september 13 please S: there is one flight at 07:45 and one at 12:00 U: what airline is the 12:00 one S: the 12:00 flight is an SAS flight U: I’ll take the 12:00 flight please –Sys provides alternatives, User makes the choice –Sys knows timetable, User knows when he wants to travel etc.

Degrees of negotiativity non-negotiative dialogue: only one alternative is discussed semi-negotiative dialogue: a new alternative can be introduced by altering parameters of the previous alternative, but previous alternatives are not retained negotiative dialogue: several alternatives can be introduced, and old alternatives are retained and can be returned to

BDI: agents What is needed for intelligent behaviour? –perception –Beliefs –Desires –planning and decistion making ability (deliberation) –Intentions –ability to act To interact, also need social attitudes –common ground –obligations¨¨¨ –committments –rights

from AI: actions (e.g. buy a ticket) have –preconditions ( seller has ticket, buyer has money) –decomposition ( … ) –effects

BDI and speech acts ”normal” actions affect the external world speech acts affect mental states of agents –i.e. their beliefs, desires, intentions, … so, speech acts can be described in terms of preconditions and effects on mental states ConvinceByInform(S, H, P) [Allen] –roles: S=speaker, H=hearer, P=proposition –precondition: bel(S, P) –effect: bel(H, P)

later developments Traum –incorporate social attitudes –model the fact that utterances are not always successful initiate_assert(S, H, P) –precondition: int( S, mbel( S, H, P ) ) –effect: bel( H, int( S, mbel( S, H, P ) ) ) acknowledge_assert( S, H, P ) –precondition: bel( S, int( H, mbel( S, H, P ))) –effect: mbel( S, H, P )