Textual Entailment (Teza de Doctorat, coordonator: prof.dr. Dan
Cristea)
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ABSTRACT
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Recognising Textual Entailment (RTE) was proposed in 2005 as
a generic task, aimed at building systems capable of capturing
the semantic variability of texts and performing natural language 
inferences.
These systems can be integrated in NLP applications, improving
their performance in fine-grained semantic analysis. This thesis
presents the relevant current work in the field and the author's
contribution regarding the creation of a Textual Entailment system.
Given two text fragments, the task of Textual Entailment answers
the question whether the meaning of one text can be inferred(entailed)
from another text. The second chapter presents an overview of
the main approaches used by systems participating in RTE competitions
from 2005 to 2008, with their strengths and weaknesses. The methods
used for identifying the entailment relation are varied, ranging
from simple methods such word overlap, to complex methods that
use semantic knowledge, logical provers,probabilistic models
or learning models. Since the 2007 edition, the participating
systems demonstrated their maturity and utility in others tracks
such Question Answering and Answer Validation Exercise of CLEF2007. The
author's contribution is outlined in the third and fourth chapters,
where a detailed presentation of the Textual Entailment developed
system is given. The system's performance was high in RTE competitions
and was ranked as one of the top Textual Entailment applications.
In order to improve on the running time, the system architecture
adopted was the peer-to-peer model, and the system behaviour is
similar to that of a computational Grid. Chapter five presents
how the Textual Entailment system was used with success in the QA@CLEF
competition, in order to improve the quality of the Question
Answering system for the Main task and the Answer Validation Exercise.
          
SPEAKER(S)
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Asist.dr. Adrian IFTENE
Universitatea Alexandru Ioan Cuza, Facultatea de Informatica
Iasi
Romania
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