Information state and dialogue
management in the TRINDI
Dialogue Move Engine Toolkit,
Larsson and Traum 2000
D&QA Reading Group, Feb 20th 2007
Genevieve Gorrell
Information State Approach

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Information state comprises cumulative
additions from previous actions in the dialogue
“Superset” of finite state approaches since the
state can easily be characterised as the
information state but the information state is too
rich to be rendered as a tractable finite state
representation
Richer than structural approaches, more
transparent than plan-based approaches ...
Information state theory of dialogue
comprises
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
Informational components
Formal representation of the informational
components
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Dialogue moves
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Update rules
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Update strategy
Informational Components

Choose your own theory

BDI?

Static/dynamic distinction may prove useful

Dialogue Gameboard (Ginzburg)

Private/shared elements
Formal Representations of
Informational Components


Simple abstract data types, logics, statistical
systems ...
Lists, sets, stacks etc.
Dialogue Moves

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A representation of the input/whatever you are
going to update based on
Abstracts about the meaning/intention of the
input

A variety of taxonomies exist

Logical forms etc.
Update Rules

Formalise information state update

Comprise

applicability conditions

effects
Update Strategy

How to apply the rules?

Take the first rule that applies

Apply each rule (if applicable) in sequence

Apply rules according to class

Choose among applicable rules using probabilistic
information

Present choices to user to decide (for development
modes)
Example
Sys: Where do you want to go?
Usr: Malvern


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
System has agenda item to ask user's destination
This meets conditions for update rule that selects “ask”
move
System asks the question and applies the integrate
rule shown earlier
Rule moves the question from the private agenda to
the shared questions under discussion
What is TRINDIKIT?

TRINDIKIT is a dialogue move engine toolkit

Provides basic architecture

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Provides facilities for implementing theories of
information state
Does not provide:

User interface
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Interpretation

Generation

Control
Example Architecture
Architecture cont.

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Total Information State (TIS)

Information State

Hookups to additional resources
Dialogue Move Engine (DME)

One or more DME modules

DME-external modules

Control module, synchronous or asynchronous
TRINDIKIT also provides ...
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Datatype definitions
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Language and format for TIS update rules
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Methods for accessing the TIS
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Algorithm definition language for DME and control modules

Default modules for input, interpretation, generation and
output

Methods for converting items from one type to another (?)
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Methods for visually inspecting the TIS
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Debugging
GoDiS 1
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Simple grounding phenomena
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Question accommodation
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Task accommodation

8 dialogue move types


ask, answer, repeat, request_repeat, greet,
goodbye, thank, quit
Private, shared distinction in IS

shared information has been explicitly established
in the dialogue
GoDiS 2
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Shared information comprises:

propositions

questions under discussion

latest dialogue move (speaker, move type, content)
Private information comprises

beliefs

agenda

plan (actions that are long term goals, editable during
dialogue. How is this different to the agenda?)

tmp (mirrors shared fields, however information is not yet
grounded)
GoDiS—Accommodation 1
Sys: Welcome to the travel agency!
Usr: flights to paris
Sys: What city do you want to go from?
GoDiS—Accommodation 2

If the answer A is the answer to a question Q
that it is in the plan to raise, then delete that
question from the private plan and add the
question to the shared questions under
discussion (?)
GoDiS Update Algorithm

Rule types comprise refill, grounding, integrate,
accommodate, database and store
EDIS 1
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Information state comprises:

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common ground
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obligations
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social commitments
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dialogue history
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conditional statements
semi-public


grounded discourse units
private

intentions
EDIS 2

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Current and previous discourse units are
included
Ungrounded discourse units feature
EDIS Update Algorithm
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Create new DU, add to UDUs
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Set CDU to the new DU, set PDU to CDU

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Perform updates on the basis of backward
grounding acts
If any other type of act is observed

add to dialogue history

execute appropriate update rule(s)
Apply update rules to all parts of the IS with
newly added acts
Other TRINDIKIT Systems—MIDAS

Discourse Representational Structures

Grounding tracking a la Poesio & Traum
Other TRINDIKIT Systems—
Autoroute (Lewin)

Conversational games formalised as recursive
transition networks
Discussion


How applicable is the accommodation work in
more complex domains?
Would the work port to a conversational
domain?


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what would be the key issues?
In what ways can machine learning be
incorporated?
Is there anything missing?