tailieunhanh - Báo cáo khoa học: "Semantic Representation of Negation Using Focus Detection"

Negation is present in all human languages and it is used to reverse the polarity of part of statements that are otherwise affirmative by default. A negated statement often carries positive implicit meaning, but to pinpoint the positive part from the negative part is rather difficult. This paper aims at thoroughly representing the semantics of negation by revealing implicit positive meaning. The proposed representation relies on focus of negation detection. For this, new annotation over PropBank and a learning algorithm are proposed. . | Semantic Representation of Negation Using Focus Detection Eduardo Blanco and Dan Moldovan Human Language Technology Research Institute The University of Texas at Dallas Richardson TX 75080 USA eduardo moldovan @ Abstract Negation is present in all human languages and it is used to reverse the polarity of part of statements that are otherwise affirmative by default. A negated statement often carries positive implicit meaning but to pinpoint the positive part from the negative part is rather difficult. This paper aims at thoroughly representing the semantics of negation by revealing implicit positive meaning. The proposed representation relies on focus of negation detection. For this new annotation over PropBank and a learning algorithm are proposed. 1 Introduction Understanding the meaning of text is a long term goal in the natural language processing community. Whereas philosophers and linguists have proposed several theories along with models to represent the meaning of text the field of computational linguistics is still far from doing this automatically. The ambiguity of language the need to detect implicit knowledge and the demand for commonsense knowledge and reasoning are a few of the difficulties to overcome. Substantial progress has been made though especially on detection of semantic relations ontologies and reasoning methods. Negation is present in all languages and it is always the case that statements are affirmative by default. Negation is marked and it typically signals something unusual or an exception. It may be present in all units of language . words incredible clauses He doesn t have friends . Negation and its correlates truth values lying 581 irony false or contradictory statements are exclusive characteristics of humans Horn 1989 Horn and Kato 2000 . Negation is fairly well-understood in grammars the valid ways to express a negation are documented. However there has not been extensive research on detecting it and more .