U1, Speech in the interface:2. Dialogue Management1 Module u1: Speech in the Interface 2: Dialogue...

U1, Speech in the interface:2. Dialogue Management 1

Module u1:

Speech in the Interface2: Dialogue Management

Jacques Terken

HG room 2:40tel. (247) 5254

[email protected]


contents

1. Tasks of the dialogue manager

2. Initiative/Control

3. Dialogue structure

4. Dealing with channel and technology limitations


Dialogue phenomena

Natural language phenomena:

User: “a flight from Boston to New York”

System: “7:15 with Continental”

User: “A later one?” [ flight from B. to NY.]


Recognition of user’s dialogue act

U: “I want a flight from Boston to New York”

syntactically: statement

pragmatically: request for information Dealing with recognition errors, misunderstandings and

other communication problems

U: A flight from Boston to New York

…

S; I’ve booked a flight from Houston to Newark …

In addition, users often have problems to know what kind of reaction is expected for successful communication


DM tasks

Interpreting user contribution in dialogue context and situational context– Dealing with natural language phenomena– Recognition of user’s dialogue act– Involves dealing with recognition errors,

misunderstandings and other communication problems

Deciding on next system contribution


Deciding upon next system contribution

Interaction as co-operation – User and system co-operate to achieve a goal– transmission of information across

communication channel may induce distortions

distinction between task-oriented acts and dialogue control acts


Task-oriented dialogue acts– Bring the dialogue purpose closer– WH-question, YN-question, Inform, WH-answer, …

Dialogue control acts – Directed towards keeping dialogue on the track and

prevent and deal with problems , e.g. • Requests for clarification• Verification• Feedback/confirmation• Error recovery strategies• But also greetings, apologies etc.


contents






Initiative

System initiative

S: Where are you travelling to

U: London

S: What day do you wish to travel

U: Friday

S: At what time

U: 9 a.m


User initiative:

U: How many employees living in the London area earn more than 50000 ₤

S: Fifty four

U: How many are female

S: Eleven

U: And managers

S: Nine


Mixed initiative

S: Where are you travelling to

U: I want to fly to London on Friday

S: At what time do you want to fly to London

U: Are there any cheap flights


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Finite-state dialogue grammar

Dialogue structure represented as finite state transition network

Departure town arrival town date time carrier

With repair sub-dialogues:

a b c d

a b c d

r r r r


Destination?

Was that $Destination?

Day?

Was that $Day?

yesno

no yes

London

Friday


Frame-based approach

Dialogue Frame:

Departure airport

Destination airport

Date

Time

Carrier Onset condition: All parameters unknown Condition action pairs produce dialogue structure:

Condition: Origin and destination unknown

Question: Which route do you want to travel


Destination Day Time


Constraint relaxation and narrowing “I want a flight from Boston to New York Friday

morning, leaving between 7:15 and 7:45” If no records are found, ask user to be more

general If many options are found (e.g. ≥ 5), ask user to

be more specific If 1 ≤ number of found options < N (e.g. 5),

generate response that outputs the retrieved records:

“I found the following flights: ….”


Cooperative dialogue Don’t ask user to be more specific or more

general, but propose solutionsE.g. U: Is there a flight from Boston to New York between 7:15 and 7:45?S’: NoS’’: No, but there is a flight at 7:55. Do you want me to book that one?

Requires understanding the user’s intentions and priorities:S’’’: * No but there is a flight to Philadelphia between 7:15 and 7:45


Theoretical frameworks for dialogue management Plan-based approaches

Dialogue as a special instance of rational (goal-directed) behaviour

System job is to discover and react adequately to the speaker’s plan rather than the utterance

Modelling of Beliefs-Desires-Intentions

Adds modeling of assumptions and beliefs that speaker has, in order to identify common ground

Rational agency (dialogue management from first principles)

Agent-based approaches (combination of plan-based approaches and local repair mechanisms with heterogeneous control)


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Technology limitations: speech recognition errors Channel limitations:

– Speech is sequential and volatile Requires feedback at different levels of

communication:– Perception– Interpretation– Evaluation

Grounding theory (Clark): dialogue as joint activity; reaching agreement over what was said and meant


Dialogue strategies

Zooming

Asking general questions first and narrowing down if no adequate response is received

“How may I help you” Adequate prompts are important

– They inform the user about what kind of reply is expected

– Require iterative design in combination with user studies (collecting extensive set of user reactions)


Verification strategies Verification provides feedback and ensures that

both participants stay in agreement about the state of the dialogue (what was said and agreed)

Explicit verification– So you want to go to New York

Implicit verification– What time do you want to arrive in New York

Confidence-based verification– Repeat question with very low confidence– Explicit verification with low to intermediate confidence– Implicit verification with higher confidence– No verification with very high confidence


Project Exercises

– Start from the original pizza application– Implement different verification strategies, both

explicit and implicit– Try the system while simulating speech

recognition errors• Hint: wreck one of the options and run a

scenario Project

– Conduct a task analysis (or construct use cases) and define the basic dialogue structure

U1, Speech in the interface:2. Dialogue Management1 Module u1: Speech in the Interface 2: Dialogue...

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