Dictionary creation device and dictionary creation method

A dictionary creation method for creating a dictionary used for searching, classifying, or filtering information written as text, said method comprising:

• extracting a keyword from a text information group made up of one or more pieces of text information;
• finding statistics regarding an appearance of the keyword within the text information group;
• calculating an assessment value for the keyword based on the statistics;
• storing, in a keyword storage unit, a pair made up of the keyword and the assessment value of that keyword;
• determining 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 in said calculating and the assessment value stored in said keyword storage unit;
• and
• registering or deleting the keyword in the dictionary based on a result of the determination.

A program for creating a dictionary used for searching, classifying, or filtering information written as text, said program causing a computer to execute the steps of:

• extracting a keyword from a text information group made up of one or more pieces of text information;
• finding statistics regarding an appearance of the keyword within the text information group;
• calculating an assessment value for the keyword based on the statistics;
• storing, in a keyword storage unit, a pair made up of the keyword and the assessment value of that keyword;
• determining 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 in said calculating and the assessment value stored in said keyword storage unit;
• and
• registering or deleting the keyword in the dictionary based on a result of the determination.