A Glimpse on Some Dialogue Systems

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A Glimpse on Some Dialogue Systems

• Arthur Chan

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Introduction

• Questions to ponder
• What is a dialogue?
• What is a dialogue system?
• What are the issues of building a dialogue
  system?
• How current dialogue systems address the issues?

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The term dialogue

• From Merriam and Webster
• a a conversation between two or more persons
  also a similar exchange between a person and
  something else (as a computer)
• The term conversation a (1) oral exchange of
  sentiments, observations, opinions, or ideas
• b an exchange of ideas and opinions
• c a discussion between representatives of
  parties to a conflict that is aimed at resolution

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A Dialogue could be

• Two parties or more (Lets call them John and
  Mary)
• John and Mary talk about politics
• Goal an exchange of ideas about something
• John and Mary talk about how to solve a problem.
• Goal try to solve a problem
• John and Mary talk about nothing. A random
  chitchat
• (Actually very common in human dialogue)
• Goal? an exchange of sentiment?, make
  themselves feel better by talking? or even
  there is no goal?

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A Dialogue Systems

• Systems that
• Allow exchange between human and computer
• Simplistic point of view
• 3 components
• Input lt- Could be spoken input, keyboard typing,
  gesture, facial expression, sign language etc.
• Control Unit lt- Process the input and generate
  and output.
• Output lt- Could be spoken output, rendered
  animation

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Outline of this talk

• Focus on Spoken Dialogue System (SDS)
• Presenting 3 papers
• Paper 1 (13 pages)
• Steps toward graceful interaction in spoken and
  written man-machine communication Philip J.
  Hayes and D. Raj Reddy
• Written in 1983
• A paper discusses detail of what issues of
  dialogue system research
• Also outlines a lot of interesting issues in the
  field

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Outline of this talk (cont)

• 2 systems are selected
• Both are representative
• Both are trying to solve real problems
• Both are quite recent (written at 98, 01)
• Paper 2 TRIPS project (previously TRAINS) by
  CISD
• Toward Conversational Human-Computer
  Interaction by James Allen et al. (7 pages)
• Paper 3 CMU Communicator
• Creating Natural Dialogs in the Carnegie Mellon
  Communicator System by A. I. Rudnicky et al. (5
  pages)

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Some Perspectives

• Did recent systems solve what Hayes and Reddy
  raise?
• Are there new issues emerge in recent years?
• System architectures of the two systems are
  different, does it matter?

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Paper 1 Steps toward graceful interaction in
spoken and written man-machine communication
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About Paper I

• Written in 1983
• Most authors of the referred systems become
  professors
• Computation is limited at the time
• Most are discussion
• U will mean user, S will mean system

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Graceful Interaction

• Graceful interaction
• involve dealing appropriately with an anything
  a user happen to say
• Proposed components for graceful interaction
• Robust Communication
• Flexible Parsing
• Domain Knowledge
• Explanation Facilities
• Focus Mechanisms
• Identification from Descriptions
• Generation of Descriptions

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Robust Communication

• Sometimes even humans misunderstand others.
• U Hello! Are you there?
• Implicit Confirmation e.g
• Speaker assume that the information received
  correctly unless the listener state otherwise e.g
  S ltnothinggt
• Implicit Acknowledgement e.g.
• S Yes! Can you hear me?
• Explicit Indication of Incomprehension
• S What did you say?
• Echo S Aha.
• Fragmentary Recognition
• S (If Hello is recognized), Hi.
• S (If Are you there? is recognized), Yes.

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Flexible Parsing

• Human conversation
• Usage of Idioms
• Phrase whose interpretation cannot be obtained
  by using the components of the phrase in the
  usual way
• Fragmentary utterance e.g.
• Alright when give me and the number for Joe
  Smith were recognized out of
• Would you be so kind to give me your listing of
  the number for Joe Smith?
• Not Good in
• I asked you to give me the number for Joe Smith,
  but I meant Fred.

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Flexible Parsing (cont.)

• Omissions, repetitions and noise phrase e.g.
• What is er could er you ggive me the number er
  the extension for Joe Smith?
• Grammatical Errors
• E.g. Just listen to Arthur Chan
• Ellipsis
• Omission of words in a sentence but could be
  obviously understood.
• E.g.
• U What is the number for Mr. Smith?
• S Do you mean Joe Smith or Fred Smith?
• U Joe. (Instead of I mean Joe Smith)

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Flexible Parsing (cont.)

• Standard parsers,
• Fail easily in repetition/omissions
• Pattern matcher could handle idioms
• No easy solution for ellipsis

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Domain Knowledge

• Simple Service
• The customer or client identify certain entities
• The entities could be regarded as parameters.
• Frame-based system (Minsky 75)
• Frames
• A method of knowledge representation
• A frame is a representation of one entity in
  terms of the entities which make its part.
• Frame have already have be used successfully
  in systems

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Explanation Facilities

• Questions about ability indirect speech acts
• Can you swim? (Interpret literally)
• Can you open the window? (Request of an action)
• Questions about ability in a restricted domain
• Can you tell me the number of Joe Smith?
• Event Question
• What did you just say?
• Did you just ask for my name?
• Hypothetical Question
• If , what will happened?

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Goals and Focus

• Human conversation are goal-oriented
• (?)
• Goals in spoken dialogue systems could be
  simplified
• 1, it has no independent goals of its own, its
  only goal is to help the user fulfill his goals.
• 2a, the users goal are either to avail himself
  of the systems highly limited services,
• or 2b, fall into an undistinguished class for
  which the system in unable to help the user.

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Goals and Focus (cont.)

• Goals could be divided to subgoals
• Focus is
• An extension of focus by equating it with the
  currently active subgoal

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Identification from Descriptions

• The identification capability of
• a listener to use a speakers description of a
  previously memorized entity to identify an
  object.
• Systems need to deal with
• Ambiguous Descriptions
• U What is the number for Smith?
• The user may try to change the description when
  being disambiguated What is the number of
  Smythe?
• Unsatisfiable Descriptions, possible response
• S There is no listing for Smith.
• Description and Faulty Comprehension
• U What is the number for ltGARBLEgt Smith?
• S Did you say Jim Smith and Joe Smith?

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Language Generation

• Different ways of saying the same thing could
  mean different
• E.g. U Do you mean Jim Smith or Fred Smith?
• S Jim Smith. or I mean Jim Smith.
• E.g. Restaurant systems was unsure about its
  recognition of seven in
• U Id like a reservation for seven people
• S What time would your party of seven like to
  eat?
• (This provide implicit confirmation.)

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Language Generation (cont.)

• Sometimes systems response could change the
  users response
• U I would like the extension of Mr. Smith
• E.g. if the system dont understand the extension
• (Appropriate) Do you mean Joe Smith or Jim
  Smith?
• (Less appropriate) What is the meaning of
  extension?
• Knowledge of standard transformation and
  conformations plays a role
• Systems should understand distant way to say
  something
• S Would you prefer 7 oclock or 8 oclock?
• U (Acceptable) I prefer 7 oclock
• U (Should also be acceptable(?)) 7 oclock is
  my preference

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Summary of Paper I

• Graceful interaction requires systems to behave
  more intelligently than a simple input/output
  system
• 7 components are discussed.
• Further reading
• Natural Language Understanding by James Allen.

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Discussion
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Paper II Towards Conversational Human-Computer
Interaction
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About Paper II

• Mainly about conversational human-computer
  interaction.
• The Rochester Interactive Planning System (TRIPS)
  
• Mentioned as a practical dialogue system
• We are now back to the modern time

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How the author see SDS

• About System
• Not to engage you in a dialogue
• But to enhances the richness of dialogue
• About Spoken User Interface
• Could be as effective as GUI
• If viewed as mixed-initiative dialogue,
• can be viewed as man-machine interaction after
  human collaborative problem solving

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Dialogue Task Complexity

• Finite-state Script (Least complicated)
• Example Long Distance Dialing
• Dialogue Phenomenon handled
• User answers questions
• Frame-based
• Example Getting trained arrival and departure
  information
• Dialogue Phenomenon handled
• User ask questions, simple clarification by system

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Dialogue Task Complexity (cont.)

• Sets of Contexts
• Example Travel Booking Agent
• Dialogue Phenomenon handled
• Shift between predetermined topics
• Plan-based Models
• Example Kitchen design consultant
• Dialogue Phenomenon handled
• Dynamically generated topic structures,
  collaborative negotiation subdialogues

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Dialogue Task Complexity (cont.)

• Agent-based Task
• Example Disaster Relief Task
• Dialogue Phenomenon handled
• A dynamically changing world
• Different modalities involved
• TRIPS focused on
• primarily interested in design of the last
  two-levels of dialogue systems

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Hypothesis of Dialogue Systems

• The Practical Dialogue Hypothesis
• The conversational competence required for
  practical dialogues, while still complex, is
  significantly simpler to achieve than general
  human conversational competence.
• The Domain-Independence Hypothesis
• Within the genre of practical dialogue, the bulk
  of the complexity in the language interpretation
  and dialogue management is independent of the
  task being performed.

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Four challenge mentioned

• Parsing Language in Practical Dialogues
• Integrating Dialogue and Task Performance
• Intention Recognition
• Mixed-Initiative Dialogue

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Architecture
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Summary of Paper II

• Present a more detailed point of view on
  identifying dialogue complexity.
• New challenges
• System architecture becomes important when agents
  need to work with each other.
• Recognition Intention

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Further Reading

• CISD web page
• http//www.cs.rochester.edu/research/cisd/
• Further Technical Detail of TRIPS
• An Architecture for a Generic Dialogue Shell
• TRAINS
• The Design and Implementation of the TRAINS-96
  System A Prototype Mixed-Initiative Planning
  Assistant

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Paper III Creating Natural Dialogs in the
Carnegie Mellon Communicator System
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About Paper III CMU Communicator

• DARPA Communicator
• Travel Booking application
• Participants MITRE, CSLU, BBN, CMU, SRI (not
  exhaustive)
• Several open systems were created.
• MITRE GalaxyCommunicator
• CMU Communicator.
• From Paper II, it is a set of contexts
  application.

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How the author see

• The travel-planning domain is interesting because
• the sequence of interactions . is not easily
  reduced to a fixed sequence of steps .
• simple form-based approaches (e.g., 6) are
  difficult to adapt to this domain because
• structure of form could be unpredictable.
• The user goal could easily change.

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Task-based Dialog Management

• Task
• Successful completion of a task
• Two parties agree on a particular result (e.g.
  itinerary)
• Some understanding of how to complete a task
• A representation for the domain-specific
  information
• AND A representation captures the structure of
  activity

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Products and Schema

• A product
• Holds the result of the interaction
• A schema
• How element of product could be interacted about

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An itinerary

• An itinerary
• A hierarchical structure
• Essentially are dynamically constructed form
• Tree structure will allow inheritance of
  information.
• Creating an itinerary
• Composition of the structure
• Population of the structure with trip-specific
  information

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System Architecture
Note From MITRE Communicator
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Summary of Paper III

• More stress on how the system could be
  implemented
• Further info
• MITRE Communicator
• http//communicator.sourceforge.net/
• CMU Communicator
• http//www.speech.cs.cmu.edu/Communicator/
• CU Communicator

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Conclusion

• Generally about SDS
• There are still a lot of challenges in dialogue
  syste
• Current practical systems are working on limited
  domain
• Practical system require higher complexity
• System architecture becomes important because
  different agents will need to work with each
  other
• Hayes paper
• Some issue could be greatly simplified in
  practice
• Robust parsing, handling of ellipsis
• Some issue may not be appreciated as much
• Dialogue management.

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QA