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 • 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 • 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 • 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 • 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

Interaction Turn Question Answer Constraints Justification CoreInfo EAT ContextOf Utterance ComplInfo IQA ontology

IQA ontology Interaction Turn Question Answer Constraints Justification CoreInfo EAT ContextOf Utterance ComplInfo

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) 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

IQA ontology Interaction Turn Question Answer Constraints Justification CoreInfo EAT ContextOf Utterance ComplInfo

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 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 • 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 • 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 • 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.

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

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

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 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 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) • 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) • 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 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) • 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?

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 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 • 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

Thank you for your attention

Towards Interactive Question Answering: An Ontology-based Approach