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Towards Interactive Question Answering: An Ontology-based Approach Bernardo Magnini, Manuela Speranza Milen Kouylekov and Vikask Kumar Fondazione Bruno Kessler - IRST (Trento - Italy) Outline Question Answering (vs. Information Retrieval)

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towards interactive question answering an ontology based approach

Towards Interactive Question Answering:An Ontology-based Approach

Bernardo Magnini, Manuela Speranza

Milen Kouylekov and Vikask Kumar

Fondazione Bruno Kessler - IRST

(Trento - Italy)

outline
Outline
  • Question Answering (vs. Information Retrieval)
  • an Ontology-based approach towards Interactive Question Answering relying on:
    • Interactive Question Answering (IQA) ontology
    • Dialogue templates based on the IQA ontology which model the interaction with the user
  • Conclusions and future work
question answering
Question Answering
  • Proliferation of digital data raises the need for technologies that allow efficient information access
  • Information Retrieval
    • Search based on keywords
    • Returns whole documents potentially containing the desired information
    • Not suitable for more specific user needs
  • Question Answering (QA)
    • Request expressed in natural language
    • Provides concise answers
    • Can address specific information needs
towards interactive qa
Towards interactive QA
  • Natural interaction with the user
    • Comprehensive and rich answer presentation
    • Provide explanations when no answer can be provided
    • Ask clarification questions for underspecified requests
    • Manage follow-up questions when a single answer does not satisfy the user completely
  • Context-aware Question Answering
  • Adaptation to different presentation scenarios
    • Different media (mobile devices, computer screens, etc.)
    • Different modalities (speech, short text messages, interaction with digital assistants, etc.)
  • Possibility of providing answers in different languages
ontology based approach
Ontology-based Approach
  • Domain and language independent
  • The IQA ontology contains the concepts for defining the structure of interaction turns (i.e. questions and answers)
  • The architecture is based on domain ontologies and on the IQA domain-independent ontology:
    • Binary predicates (RDF triples) are used as basic representation structures for semantic content
    • Concepts and relations of the predicates are defined in the domain ontologies and in the IQA ontology
    • Dialogue templates are used when the intermediate RDF answer is converted into the system’s final output
slide6

Interaction Turn

Question

Answer

Constraints

Justification

CoreInfo

EAT

ContextOf Utterance

ComplInfo

IQA ontology

slide7

IQA ontology

Interaction Turn

Question

Answer

Constraints

Justification

CoreInfo

EAT

ContextOf Utterance

ComplInfo

structure of a question i
Structure of a question (i)

Expected Answer Type(EAT): the category to which the minimal answer to the question (i.e. a simple noun or a short phrase) must belong

Example: Who won the Tour de France? (EAT: Person)

Constraints:make the questiom more specific by restricting the range of elements satisfying the EAT

Examples:

Who won the Tour de France in 2000?

Which American cyclists won the Tour de France?

(constraints: won the Tour de France,in 2000,American)

Context of utterance: the time and place in which the question is uttered (E.g.: Trento March 25th 2010)

structure of a question ii
Structure of a question (ii)

Example from the cinema domain

Which cinema is showing Titanic by Cameron today in Trento?

EAT:Cinema

Constraints:is showing Titanic,by Cameron, today, in Trento

Context of utterance: March 25th, Trento

slide10

IQA ontology

Interaction Turn

Question

Answer

Constraints

Justification

CoreInfo

EAT

ContextOf Utterance

ComplInfo

core information
Core information
  • The minimal acceptable answer to a question (simply a noun or a phrase)
  • Satisfies the EAT of the question
  • Can be null (if the range of elements satisfying the EAT is empty)
  • Examples:
    • Who won the Tour de France in 2000?

Armstrong

    • Where is Titanic showing today in Trento?

Cinema Astra

justification
Justification
  • Justification provides some explanation and contextualization for the core information
    • Direct: shows that the request has been correctly understood (through constraint repetition or rephrasing)

- Where is Titanic showing today in Trento?

- Titanic is showing today at Cinema Astra in Trento

    • Derived (in case of underspecified questions): makes explicit the interpretation given to the question

- Where is Titanic showing in Trento?

- Today at Cinema Astra

- Where is Titanic showing in Trento?

- Tomorrow at Cinema Modena

complementary information
Complementary information
  • Non-mandatory additional (wrt core information and justification) information that can be added if considered useful
  • Examples:
    • Who won the Tour de France in 2000?

The American Armstrong.

    • Where is Titanic showing today in Trento?

At Cinema Astra at 8 PM.

empty answers
Empty Answers
  • Core information is null (nothing available to satisfy the constraints and the EAT)
  • Justification is required to explain the reasons for the null core information
  • Through complementary information it is possible to provide related positive information
  • Possible causes for empty answers:
    • Wrong presupposition: an explicit constraint is not satisfied
    • Missing constraint: a specific interpretation of an underspecified question leads to null core information
examples
Examples
  • Wrong Presupposition
    • Which cinema is showing Titanic by Spielberg today in Trento?
    • There is no movie called Titanic directed by Spielberg

Titanic by Cameron is showing at cinema Astra.

Spielberg directed: E.T., The color purple, etc.

  • Missing Constraint
    • Where is Shrek showing in Trento?
    • No theatre inTrento is showing Shrek today. It is

showing tomorrow at Cinema Astra.

ontology based architecture

Natural language question

IQA ontology

IQA templates

Question analysis

Query

System answer

Answer presentation

Answer extraction

RDF answer

No answer

Modified query

Failure recovery

Domain ontology

Domain templates

Ontology-based Architecture
an answer in rdf example

qmi:Answer

qmi:hasJustification

qmi:hasComplInfo

qmi:hasCoreInfo

qmi:Justification

qmi:CoreInfo

qmi:ComplInfo

qmi:justifiedValue

qmi:complValue

qmi:coreValue

qmd:23/04/2009 qmd:Trento

qmd:Cinema Astra

qmd:3PM qmd:8PM

An Answer in RDF: Example

Q: Where is Titanic showing on April 23rd in Trento?

A:On April 23rd Titanic is showing at cinema Astra in Trento at 3 PM and 8 PM

ontology based architecture18

Natural language question

IQA ontology

IQA templates

Question analysis

Query

System answer

Answer presentation

Answer extraction

RDF answer

No answer

Modified query

Failure recovery

Domain ontology

Domain templates

Ontology-based Architecture
iqa template 2 sms
IQA Template 2: SMS

Template 2

if ((mobile device) && (text))

if (qmi:CoreInformation ≠ NULL)

then set STYLE = ¬VERBOSE

provide qmi:CoreInformation

provide qmi:Justification

If the answer has to be presented in the form of short SMS, then the system provides only Core Information and Justification, leaving out Complementary Information

iqa template 3 empty answer
IQA Template 3: Empty Answer

Template 3

if ((desktop) && (digital assistant) && (speech))

if (qmi:CoreInformation = NULL)

&& (qmi:Constraint ≠ MATCHED))

then set STYLE = VERBOSE

express regret

provide qmi:Justification && qmi:Constraint

In case of empty answer (e.g. Core Information is null) due to wrong presupposition (a constraint is not consistent with the domain ontology) the system expresses regret and provides justification to the null core information by pointing out the constraint that failed to be satisfied.

interaction with the user i
Interaction with the User (i)
  • Interact with the user to deal with under-specified questions (instead of giving an answer with derived justification)
  • Question: Where is Titanic showing in Trento?
  • Answer1: Could you specify to which day your question refers?(Ask to make the missing information explicit)
  • Answer2: Time is not specified in your question. Do you wish to know about today/tomorrow? (Ask to confirm the selected interpretation)
interaction with the user ii
Interaction with the User (ii)
  • Interact with the user in the case of empty answers:
    • Wrong presupposition
  • Question: Where is Titanic by Spielberg showing today in Trento?
  • Answer1: There is no movie called Titanic directed by Spielberg. Are you interested in Titanic by Cameron?
  • Answer2: There is no movie called Titanic directed by Spielberg.Are you interested in movies by Spielberg?
a snippet from the domain ontology
A snippet from the Domain Ontology

Cinema

hasName

hasContact

isinSite

hasPostalAddress

Astra

Contact

hasEvent

hasInfrastructure

PostalAddress

Event

hasEventContent

isInDestination

hasEventContent

Destination

Movie

hasDirector

Movie

hasName

Director

duration

duration

hasDirector

hasName

hasName

Titanic

164 mins

Director

Cameron

E.T.

hasName

194 mins

Spielberg

a snippet from the domain ontology24
A snippet from the Domain Ontology

Cinema

hasName

hasContact

isinSite

hasPostalAddress

Astra

Contact

hasEvent

hasInfrastructure

PostalAddress

Event

hasEventContent

isInDestination

hasEventContent

Destination

Movie

hasDirector

Movie

hasName

Director

duration

duration

hasDirector

hasName

hasName

Titanic

164 mins

Director

Cameron

E.T.

hasName

194 mins

Spielberg

a snippet from the domain ontology25
A snippet from the Domain Ontology

Cinema

hasName

hasContact

isinSite

hasPostalAddress

Astra

Contact

hasEvent

hasInfrastructure

PostalAddress

Event

hasEventContent

isInDestination

hasEventContent

Destination

Movie

hasDirector

Movie

hasName

Director

duration

duration

hasDirector

hasName

hasName

Titanic

164 mins

Director

Cameron

E.T.

hasName

194 mins

Spielberg

interaction with the user iii
Interaction with the User (iii)
  • Interact with the user in the case of empty answers
    • Missing Constraint
  • Question: Where is Titanic showing in Trento?
  • Answer: No theatre in Trento is showing Titanic today. Are you interested in tomorrow’s scheduling?
a snippet from the domain ontology27

Schedule

15:00 hours

03/26/2010

A snippet from the Domain Ontology

Cinema

hasName

hasContact

isinSite

hasPostalAddress

Astra

Contact

hasEvent

hasInfrastructure

PostalAddress

Event

hasEventContent

isInDestination

hasEventSchedule

Destination

Movie

hasDirector

hasName

Director

duration

hasName

Titanic

Cameron

194 mins

a snippet from the domain ontology28

Schedule

15:00 hours

03/26/2010

A snippet from the Domain Ontology

Cinema

hasName

hasContact

isinSite

hasPostalAddress

Astra

Contact

hasEvent

hasInfrastructure

PostalAddress

Event

hasEventContent

isInDestination

hasEventSchedule

Destination

Movie

hasDirector

hasName

Director

duration

hasName

Titanic

Cameron

194 mins

the qall me project
The Qall-Me project

EU funded project QALL-ME: Question Answering Learning Technologies in a multiLingual and Multimodal Environment (http://qallme.fbk.eu/)

Main results: The QALL-ME Framework, the EDITS suite, the QALL-Me Benchmark, the QALL-ME Ontology (all available now from the website)

Objective: To establish a shared infrastructure for multilingual and multimodal open domain Question Answering for mobile phones

Demo for the cinema domain: http://qallmedemo.fbk.eu/tcv5/jsp/cinema.jsp

Magnini, B., Speranza, M. and Kumar, V. Towards Interactive Question Answering: An Ontology-Based Approach In: Proceedings of the Workshop on Semantic Computing and Multimedia Systems at ICSC 2009, Berkeley, California, USA, September 14-16, 2009

conclusions and future work
Conclusions and future work
  • Conclusions
    • An ontology-based approach towards interactive QA
      • IQA Ontology
      • Dialogue Templates
    • Interaction with the user
  • Future work
    • Deal with more complex factoid questions and with follow-up questions
    • Implement more Dialogue Templates
    • Evaluation