Interactive Communication Management in an Issue- based Dialogue System DiaBruck 2003 Staffan Larsson Göteborg University, Sweden [email protected].

Interactive Communication Management in an Issue-based Dialogue System

DiaBruck 2003

Staffan LarssonGöteborg University, Sweden

[email protected]

Overview

• Interactive Communication Management (ICM)

• ”Verification” in dialogue systems• Classifying and formalising feedback• Feedback moves for GoDiS• Issue-based grounding• Formalising sequencing moves for

GoDiS• Conclusions & Future work

ICM (Allwood)

• Interactive Communication Management – As opposed to Own Communication Management

(OCM): self-corrections, hesitations, etc.

• Feedback moves– (short) utterances which signal grounding status of

previous utterance (”mm”, ”right”, ”ok”, ”pardon?”, ”huh?” etc.)

• Sequencing moves– utterances which signal dialogue structure (”so”,

”now”, ”right”, ”anyway” etc.)

• Turntaking moves

ICM in current commercial systems

• Usually, limited to ”verification”• Examples (San Segundo et. al. 2001)

– I understood you want to depart from Madrid. Is that correct? [”explicit v.”]

– You leave from Madrid. Where are you arriving at? [”implicit v.”]

• Involves repetition or reformulation • Appears in H-H dialogue, but not very

common

From verification to ICM in dialogue systems

• ”Verification” is just one type of ICM behaviour– Perhaps the one most cruicial in dialogue systems

given poor speech recognition

• Could a wider range of the ICM behaviour occurring in H-H dialogue be useful in dialogue systems?

• We want a typology of ICM moves for H-H dialogue– Feedback and sequencing moves

• We want to formalise it and use it in a system– Still we will implement only a subset

• We want to relate it to grounding in a system

Classifying feedback

• Level of action• Polarity• Eliciting or non-eliciting• Form (syntactic realisation)• Content type (object- or metalevel)

Feedback levels

• Action levels in dialogue (Allwood, Clark, Ginzburg)– Contact: whether a channel of communication is

established– Perception: whether DPs are perciveving each other’s

utterances– Understanding: Whether DPs are understanding each

other’s utterances• Non-contextual (”semantic”) meaning• Contextual (”pragmatic”) meaning

– Acceptance: Whether DPs are accepting each other’s utterances

• The function of feedback is to signal the status of utterance processing on all levels

Feedback polarity

• Polarity (Allwood et.al. 1992)– Positive: indicates contact, perception, understanding,

acceptance– Negative: indicates lack of contact, perception,

understanding, acceptance– We add a ”neutral” or ”checking” polarity – there is one

or more hypotheses, but the DP lacks confidence in them

• Examples – ”I don’t understand”: negative– ”Do you mean that the destination is Paris?”: checking– ”To Paris.”: positive– ”Pardon”: negative

Formalising ICM dialogue moves

• Level– con: contact– per: perception– sem: semantic understanding (no context)– und: pragmatic understanding (relevance in context)– acc: acceptance

• Polarity– pos: positive– neg: negative– chk: checking

Feedback move notation

• icm:Level*Polarity{:Args}• Examples

– icm:per*pos:String – ”I heard you say ’londres’”

– icm:und*neg – ”Sorry, I don’t understand”– icm:und*chk:AltQ – ”Do you mean x or y?”– icm:und*pos:P – ”To Paris.”– icm:acc*neg:Q – ”Sorry, I can’t answer Q”– icm:acc*pos – ”Okay”

GoDiS: an issue-based dialogue system

• Explores and implements Issue-based dialogue management (Larsson 2002)– Based on Ginzburg’s notion of a dialogue

gameboard involving Questions Under Discussion (QUD)

– Uses (mostly pre-scripted) dialogue plans

• Extends theory to more flexible dialogue– Multiple tasks, information sharing between tasks – ICM: feedback and grounding, sequencing– Question accommodation, re-raising, clarification– Inquiry-oriented, action-oriented, negotiative

dialogue

System feedback for user utterances in GoDIS

• contact– negative (”I didn’t hear anything from you.”, ”Hello?”)

[icm:con*neg]

• perception– negative: fb-phrase (”Pardon?”, ”I didn’t hear what you

said”) [icm:per*neg]– positive: repetition (”I heard ’to paris’”)

[icm:per*pos:String]

• semantic understanding:– negative: fb-phrase (”I don’t understand”) [icm:sem*neg]– positive: reformulation (”Paris.”) [icm:sem*pos:Content]

System feedback, cont’d

• pragmatic understanding– negative: fb-phrase (”I don’t quite understand”)

[icm:und*neg]– positive: reformulation (”To Paris.”)

[icm:und*pos:Content]– checking: reformulation (”To Paris, is that correct?”,

”To Paris?”) [icm:und*chk:Content]

• acceptance/integration– negative:fb-phrase with reformulation (”Sorry, I

cannot answer Q”, ”Sorry, Paris is not a valid destination city.”) [icm:acc*neg:Content]

– positive: fb-word (”okay.”) [icm:acc*pos]

Feedback selection

• Feedback polarity selected depending on:1. Contact: Whether any speech is observed 2. Perception: Speech recognition score > threshold3. Semantics: Whether system can find a non-contextual

interpretation4. Pragmatic understanding: Whether system can find a relevant

contextual interpretation– none: extremely high score (certain of interpretation)– Positive: high score (pretty sure of interpretation)– Checking: medium score (not so sure)– Negative: low score (very unsure)

5. Acceptance: Whether system can accept what has been said• General principles

– Produce positive feedback only on highest possible level– When producing negative feedback on level N, produce positive

feedback on level N-1

Feedback on multiple levels

S> Lets see. What can I do for you? U> (mumble mumble)S> Sorry, I didnt hear what you said. What can I do for you?

U> siridusS> I heard you say siridus . Sorry, I dont understand. What can Ido for you?

U> channel oneS> channel one. I dont quite understand. Do you want to add aprogram or change channel?

Negative perception

feeback

Positive perception

Negative understanding

Positive understanding

(word meaning)

Negative understanding

(relevance) (Task clarification)

U> turn on the t vS> turn on the TV… Sorry, I cannot control the TV set. Do you want to

add a program or change channel?”

U> pardonS> Sorry, I cannot control the TV set. Do you want to add a program or

change channel?U> change channelS> Okay.

Rejection(negative

acceptance feedback)

Positiveunderstanding

User negative perception

System repetition

Positiveacceptance

Reactions to positive and checking feedback

• After check feedback, – (e.g., ”channel one, is that correct?”)– positive response is needed, or system will

assume it was wrong

• After positive feedback, – (e.g., ”channel one.”)– if user gives no response or positive response,

system continues to assume it was right;– If user gives negative response, system

assumes it was wrong• correcting the system

Correcting the system

S> Lets see. What can I do for you? U> add programS> Okay. Add a program…S> Lets see. What channel do you want? U> channel sixS> OK, channel five.U> noS> not channel five. So, What channel do you want? U> channel sixS> Okay. channel six.”

Positive feedback

Negative answer to fb.

Issue-based grounding

• Checking feedback on und-level explicitly raises understanding-issue – icm:und*chk:C raises ?und(C)

• ”Is C the meaning of the previous utterance?”– Positive response leads to adding C to shared commitments– Negative or no response leads to no action

• Positive understanding feedback does not raise the understanding-issue explicitly– In fact, tentatively assumes it has been positively resolved – but makes it available for interpretation of short answers

• in this case, ”yes” or ”no”– Negative reponse leads to retracting C– Positive or no response leads to no action

• So far, only implemented for understanding level

ISSUES, QUD and accommdation

• We distinguish QUD and ISSUES:– QUD (local): Questions available for resolution of

short answers– ISSUES (global): Issues/questions that have been

raised but not yet resolved

• QUD-to-ISSUES accommodation– If an answer is given which does not address any

question on ISSUES, – But does address a question Q on QUD– Then, accommodate Q to ISSUES (this amounts to

raising Q)

Feedback, ISSUES and QUD

• Assume previous move had content C• Checking feedback

– Push ?und(C) on ISSUES and QUD• Positive feedback

– Add C to shared commitments– Push ?und(C) on QUD (but not on ISSUES)– ”yes” or ”no” do QUD-to-ISSUES accommodation

• Integrating responses to understanding-issues– Done by a single rule, regardless of how the understanding-

issue was raised– Given that ?und(C) is on ISSUES,– ”yes” add C to shared commitments if not already there– ”no” retract C from shared commitments if it’s there

(actually, backtrack to saved previous shared commitments)

Negative response to positive feedback

S> Lets see. What channel do you want? U> channel six

S> OK, channel five.

channel (5) added to shared commitments;?und(channel (5)) on QUD

U> noQUD-to-ISSUES accommodation

?und(channel (5)) on ISSUESintegrate ”no”

retract channel(5)S> not channel five. So, What channel do you want?

Negative response to cheking feedback

S> Lets see. What can I do for you? U> add programS> Okay. Add a program…S> Lets see. What channel do you want? U> channel six

S> channel five??und(channel (5)) on ISSUES and QUD

U> nointegrate ”no” ( do nothing)

S> So, What channel do you want? U> channel sixS> Okay. channel six.”

Sequencing ICM

• Discourse particles– ”so” may be used to reraise a previously

discussed question– ”right”, ”anyway”, ”let’s see…”

• Verbose sequencing– ”Let’s talk about …”, ”Let’s return to the

issue of …”

• How do we classify these?– We correlate them with updates to the

common ground

Sequencing moves generated by GoDiS

• Formal notation schema:– icm:Type{:Content}

• Loading a dialogue plan– icm:loadplan – ”let’s see.”

• Question accommodation– icm:accommodate – ”alright.”

• Reraising an issue– icm:reraise – ”so, ”– icm:reraise:Q – ”returning to the issue of

…”

Sequencing ICM: reraising issue, loading a plan

S> Welcome to the travel agency! U> price information S> (…) Lets see. How do you want to travel? U> by flightS> (…) What city do you want to go to? U> parisS> (…) What city do you want to go from? U> do I need a visa ?S> (…) Lets see. What country are you from? U> swedenS> Okay. Yes, you need a Visa. S> Returning to the issue of price. Lets see. What city do

you want to go from?

Signals loading a plan

Reraising an issue explicitly

Sequencing ICM: Accommodation

S> Lets see. What can I do for you?U> channel five today

S> Alright. add a program… Lets see. Okay. channel five… today… What time do you want to start recording?

U> from six thirty to seven thirtyS> Okay. from six thirty… to seven thirty… The

program has been added. ”

Signals accommodation

Future work

• Replace current ad-hoc forms based on corpus studies and existing work– ”discourse markers” (Schiffrin)– ”cue phrases” (Grosz & Sidner and others)

• ”Real” generation rather than templates– Integrate ICM with other utterances, rather than just

appending them

• Explore other ways of generating ICM– Intonation, facial expression, etc.

• Extend the range of ICM generated (and interpreted) by the system

• Extend issue-based grounding to all levels

Conclusions• By extending the range of ICM used by

systems, their communication becomes more natural and comprehensive

• We have provided an initial classification of feedback and sequencing ICM useful in a dialogue system, and implemented it

• Issue-based grounding provides mechanisms allowing the user to react to system feedback

• Sequencing moves can be correlated with updates to common ground, and used to signal these updates to the user

Questions?

Relation to Traum’s computational theory of grounding

• Focus on positive feedback and corrections (self and other)– Deals with the question, when does a contribution

end? Related to turntaking.– Focus on self- and other-corrections (not included

here); involves turntaking and OCM, but also feedback– Does not include sequencing ICM– Based on the TRAINS corpus of H-H dialogue ->

(arguably) focus on positive feedback

• Focus on understanding-level– ”grounding” here refers only to the understanding

level – Acceptance and rejection seen as ”core speech acts”

Object- or metalevel content

• Utterances with metalevel content explicitly refer to contact, perception, understanding or acceptance

• Object-level utterances instead refer to the task at hand• Example

– S: What city are you going to?– U: Paris– S(1a): Did you say you’re going to Paris? [meta]– S(1b): Are you going to Paris? [object]– S(2a): Do you mean Paris, France or Paris, Texas?– S(2b): Do you want to go to Paris, France or Paris, Texas?

• This dimension does not apply to all feedback, e.g. ”Paris.”, ”Pardon?”

• (Is 2b feedback or simply an alternative question?)

Realisation of feedback moves

• Syntactic form:– declarative: ”I didn’t hear what you said.”; ”The

destination city is Paris.”– interrogative: ”What did you say?”; ”Do you want to

go to Paris?”– imperative: ”Please repeat your latest utterance!”– elliptical

• interrogative: ”Paris?”, ”To Paris or from Paris?”• declarative: ”To Paris.”

• In general, the exact formulation of ICM phrases may depend on various contextual factors– including activity, noise level, time constraints etc.

Eliciting / nonelciting feedback (Allwood et. al. 1992)

• Eliciting feedback is intended to evoke a response from the user

• Noneliciting feedback is not so intended– But may nevertheless recieve a response

• Rough correspondence / operationalisation– Checking feedback is eliciting; explicitly raises

grounding issue– Positive feedback is noneliciting; may implicitly raise

grounding issue

• What about negative feedback?– ”pardon?”,”huh?”: eliciting?– ”I didn’t hear you”: noneliciting?

Simplifying assumptions regarding feedback

• We only represent action level and polarity• Eliciting/noneliciting dimension implicit

– Negative feedback is eliciting in some sense; since something went wrong, it must be fixed

– Checking feedback is also eliciting, since it poses a question that must be adressed

– Positive feedback is not eliciting (we assume)

• Syntactic form not included in classification; decided by generation module

• Metalevel / object level perhaps not so interesting unless full compositional semantics are used– ”Do you mean that you want to Paris?” vs. ”Do you want

to go to Paris?”

Implicit feedback?• Clark: ”relevant followup” to U counts as positive

feedback– What is relevant?

• simple cases for followups to questions:– answer to question– ”subquestion”– feedback concering question

• Complex cases: all other utterances– In general, complex inference and knowledge may be needed

(implicatures)– Currently, irrelevant followup counts as negative feedback (a

cautious assumption)

• What about no followup at all?– in reaction to ask-move or interrogative feedback, counts as

negative– in reaction to answer or positive feedback, counts as positive

Rejection?

S: ”Where do you want to go?”U1: ”Nowhere”U2: ”I don’t know”

• Should these count as rejections?– U1: negative answer? presupposition

failiure? rejection?– U2: rejection?

• but not as definite as ”No comment!”

Grounding

• ”To ground a thing … is to establish it as part of common ground well enough for current purposes.” (Clark)

• making sure that the participants are percieving, understanding, and accepting each other’s utterances