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Question Answering Based on Semantic Graphs
Lorand Dali – [email protected] Rusu – [email protected]ž Fortuna – [email protected] Mladenić – [email protected] Grobelnik – [email protected]
MotivationSystem OverviewQuestion AnsweringDocument Overview
FactsSemantic GraphDocument Summary
Conclusions
Overview
Motivation
Motivation
Triplets
Facts stated in the textThe core of the sentence (subject, verb, object)
System Overview
Extract facts (triplets) from textIndex triplets to enable structured search on themAnalyze questions to obtain the queries for the triplet searchRetrieve the answer and the document containing itBrowse the document overview
Question Answering
Question Answering
Question types:Yes/No questions (Do animals eat fruit?),list questions (What do animals eat?),reason questions (Why do animals eat fruit?),quantity questions (How much fruit do animals eat?),location questions (Where do animals eat?) andtime questions (When do animals eat?).
Question Answering
Analyze the document containing the answer:
Highlight facts described by subject – verb – object triplets (identified in the Penn Treebank parse tree)
Obtain the document semantic graph
View the automatic document summary
Document Overview
Semantic Graph
DocumentPlain text format
Named entity extractionCo-reference resolution
According to traditional Chinese medical belief, mental problems, laziness, malaria, epilepsy, toothache and lack of sexual appetite can be treated with tiger parts, leading to rampant poaching of the animal in Asia , the World Wide Fund ( WWF ) said.
AsiaWorld Wide Fund WWF
Asia - location
World Wide Fund - organization
WWF -organization
Co-reference
S – V – O triplet extraction
Triplet enhancement
Semantic Graph
Document Summary
Feature Extractor
Features:linguisticdocumentgraph
Linear SVM
Linear Model
The Kerinci conservation project, an area of around three million hectares (7. 4 million acres) in west Sumatra, was being supported by funds from the World Bank, Subijanto said. [10.0912]Subijanto, a spokesman for the Forestry Ministry, said Indonesia was commited to protecting the tigers, which live within Sumatra's four designated conservation areas. [9.4155]
Rank
ing
Rank
ing
Document Summary
There are people wanting tiger products who didn't want them before, " Ron Lilley,coordinator for species conservation at the WWF in Jakarta, told Reuters.Subijanto, a spokesman for the Forestry Ministry, said Indonesia was commited to protecting the tigers, which live within Sumatra's four designated conservation areas.The Kerinci conservation project, an area of around three million hectares (7. 4 million acres) in west Sumatra, was being supported by funds from the World Bank, Subijanto said.
Enhanced question answering systemQuestion answering, where the answer is supported by documentsDocument browsing
FactsDocument semantic graphAutomatic document summary
Conclusions
Future workSystem extensions: triplet extraction, named entity recognitionExpand the search to look for answers in ontologiesRelax the requirement that the questions have a predefined formImprove the document overview functionality by integrating external resources
Conclusions
Thank you!
Questions are guaranteed in life, answers aren’t.
Extracted features:
Document Summary
Linguistic Attributes (13) Document Attributes (11)
Graph Attributes (9)
•Logical form tag•Treebank tag•Part of speech tag•Depth of linguistic node•8 semantic tags for named entities
•Sentence related: e.g. – location of sentence within doc•Triplet related: e.g.- frequency of triplet element in sentence, in doc, …
•Authority and Hub weight, Page Rank•Node degree•Size of weakly connected component•Size of max length chain•Frequency of verbs among edges
Document Summary
Rank
(Inf
orm
ation
Gai
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