INFORMATION EXTRACTION SYSTEM, INFORMATION EXTRACTION METHOD, AND INFORMATION EXTRACTION PROGRAM

摘要

An opinion/emotion word detection unit browses an opinion/emotion dictionary, finds matches, detects opinion/emotion words in an obtained character string, and applies absolute polarity thereto. A term polarity determination unit detects terms on the basis of co-occurrence with opinion/emotion words, and determines the polarity of the terms on the basis of the absolute polarity of the opinion/emotion words. A determination range expansion unit expands word strings including words connected to terms, and determines the polarity of a word string for determination. A series of individual determinations are repeated, and a determination tallying unit tallies the individual determination results for each word string for determination. A consolidated polarity determination unit calculates a ratio (N) on the basis of the number of positive determinations and the number of negative determinations, and makes a consolidated determination. An expression extraction unit extracts the consolidated determination result and outputs same to an expression word string dictionary.

主权项

1. An information extraction system comprising:
an opinion/emotion dictionary that stores opinion/emotion words (or word strings) relevant to absolute positive expressions and opinion/emotion words (or word strings) relevant to absolute negative expressions, the words having a polarity remaining unchanged regardless of a context; a language analysis unit that acquires an optional character string from a text and performs language analysis for the character string to divide the character string into words and provide a prototype and a part of speech for each of the words; an opinion/emotion word detection unit that detects an opinion/emotion word (or a word string) from the acquired character string by preforming a matching between the prototype of each of words as the analysis result by the language analysis unit and an opinion/emotion word (or a word string) in the opinion/emotion dictionary; a declinable word polarity determination unit that determines a polarity of a declinable word based on an absolute polarity of the opinion/emotion word (or the word string) by detecting the declinable word before and after the opinion/emotion word (or the word string) from the acquired character string based on co-occurrence with the opinion/emotion word (or the word string); a determination range expansion unit that determines polarity by expanding a polarity determination range from the declinable word to word strings obtained by linking the declinable word with at least one word before and after the declinable word; a determination number tallying unit that tallies a positive determination number and a negative determination number for each determination target word string by repeating a single determination of polarities of the declinable word and the expanded determination target word strings for another character string included in the text; a consolidated polarity determination unit that performs a consolidated determination whether the determination target word strings are a positive expression or a negative expression based on the positive determination number and the negative determination number; and an expression extraction unit that extracts a word string (or a word) relevant to a positive expression and a word string (or a word) relevant to a negative expression based on the determination result of the consolidated polarity determination unit.