Patent ID: 7840565
Filing Date: 2010-11-23
Classification: G06F,H04N

Abstract:
1. A dictionary creation device that creates a dictionary used for searching, classifying, or filtering information written as text, said device comprising: a keyword extraction unit configured to extract a keyword from a text information group made up of one or more pieces of text information; a keyword statistics unit configured to find statistics regarding an appearance of the keyword within the text information group; a keyword assessment value calculation unit configured to calculate, using a processor, an assessment value for the keyword based on the statistics; a keyword storage unit configured to store a pair made up of the keyword and the assessment value of that keyword, said keyword storage unit being a memory unit; a determination unit configured to determine whether or not to register the keyword in the dictionary, or whether or not to delete the keyword from the dictionary, based on a degree of change between the assessment value newly calculated by said keyword assessment value calculation unit and the assessment value stored in said keyword storage unit; and a dictionary registration and deletion unit configured to register or delete the keyword in the dictionary based on a result of the determination, wherein the assessment value calculated by said keyword assessment value calculation unit is an appearance frequency at which the keyword appears in the text information group, wherein said determination unit is configured to determine to delete the keyword from the dictionary in the case where the keyword is already registered in the dictionary and a degree of change in the appearance frequency is greater than or equal to a predetermined threshold value, the degree of change in the appearance frequency indicating a difference between the appearance frequency and a previously calculated appearance frequency, and wherein the same keyword is used for calculating the appearance frequency and the previously calculated appearance frequency.