NATURAL LANGUAGE SENTENCE RELATION DECIDING DEVICE, NATURAL LANGUAGE SENTENCE RETRIEVING DEVICE, NATURAL LANGUAGE SENTENCE GENERATING DEVICE, FRAMED EXPRESSION OUTPUT DEVICE TO BE USED FOR THE SAME, METHOD THEREFOR AND RECORDING MEDIUM

摘要

PROBLEM TO BE SOLVED: To improve the accuracy of data retrieval using a key sentence by deciding similarity/non-similarity between sentences after considering a difference between the meaning of both the sentences. SOLUTION: A similarity retrieval engine 10A extracts words from an input character string inputted from an external device 90 and the other character string while classifying them into conceptual word, affix, relational expression or postpositional expression (step S130) and discriminates the similarity between the extracted words (inter-word similarity) while referring to a conceptual word thesaurus 36a or functional expression thesaurus 36b (step S140). While using the value of this inter-word similarity between respective words, similarity between each word string of the input character string and the word string of the comparative character string (inter-word string similarity) is successively found (step S150) and the similarity between the word string including all words in the input character string and the word string including all words in the comparative character string is decided as similarity between the input character string and the comparative character string.