Post on 21-Dec-2015
transcript
Generating Feedback and Sequencing Moves in a
Dialogue SystemAAAI Spring Symposium 2003
Staffan LarssonGöteborg University, Sweden
Overview
• Interactive Communication Management (ICM)
• ”Verification” in dialogue systems• Classifying and formalising ICM• ICM for a dialogue system• Examples• 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.)– Dialogue structure part of / modeled by common
ground
• Turntaking moves
Grounding and ICM in current commercial systems
• 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, but more than
verification
Classifying feedback
• Level of action• Polarity• Eliciting / noneliciting• 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
• Action levels– con: contact– per: perception– sem: semantic understanding (no context)– und: pragmatic understanding (relevance in context)– acc: acceptance
• Polarity– pos– neg– chk (”int” in paper)
Feedback move notation
• icm:Level*Polarity{:Args}– 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”
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]– checking: reformulation (”Paris, is that correct?”, ”Paris?”)
[icm:sem*chk: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 (for each level respectively):– Contact: Whether any speech is observed – Perception: Speech recognition score– Semantics: Whether system can find a non-
contextual interpretation– Pragmatic understanding: Whether system
can find a relevant contextual interpretation– Acceptance: Whether system can accept
what’s been said
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
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 will correlate them with updates to the
common ground
Sequencing moves generated by GoDiS
• Formal notation schema:– icm:Type{:Content}
• Loading a 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
Conclusions
• Current dialogue systems use only a fraction of the range of ICM used by humans
• 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
• (ICM can be correlated with updates to common ground, and used to signal these updates to the user)
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
Questions?
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.
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.”
(dialog4_edit)
Interrogative feedback
Negative answer to fb.
Signals reraising an issue (Sequencing
ICM)
Reactions to positive and checking feedback
• After positive feedback, system leaves a pause for the user to agree or disagree– if user gives no response, system
assumes it was right
• After check feedback, positive response is needed– or system will assume it was wrong
Implicit feedback?
• Clark: ”relevant followup” to U– 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
• 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!”
Relation to Traum’s computational theory of
grounding• Focus on understanding-level
– ”grounding” here refers only to the understanding level
– Acceptance and rejection seen as ”core speech acts”
• Focus on positive feedback and corrections (self and other)– Based on the TRAINS corpus of H-H dialogue– Deals with the question, when does a contribution
end?– Corrections not included here; involves turntaking
and OCM
• Does not include sequencing ICM
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 – Feedback and grounding– Question accommodation, re-raising, clarification
– …
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
Simplifying assumptions regarding feedback
• We only represent action level and polarity• In polarity, we replace ”neutral” by ”checking”
– We exclude feedback which is neutral but not check-questions
• Eliciting/noneliciting dimension implicit– Negative feedback is eliciting; 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
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