INFORMATION SEARCH METHOD, APPARATUS, PROGRAM AND COMPUTER READABLE RECORDING MEDIUM

• US 20100257159A1
• Filed: 09/10/2008
• Published: 10/07/2010
• Est. Priority Date: 11/19/2007
• Status: Active Grant

• Current Assignee: Nippon Telegraph and Telephone Corporation
• Original Assignee: Nippon Telegraph and Telephone Corporation
• Inventors: Kataoka, Ryoji, Uematsu, Yukio, Fujioka, Kengo, Konagai, Syunsuke
• Granted Patent: US 8,909,654 B2
• Time in Patent Office: Days
• US Class Current: 707/723
• CPC Class Codes: G06F 16/313 Selection or weighting of terms for indexing
• CPC Class Codes: G06F 16/316 Indexing structures
• CPC Class Codes: G06F 16/334 Query execution G06F16/335 takes precedence

Abstract

An information search apparatus is provided. The information search apparatus includes: a character string input unit configured to obtain a character string from a client; a character string information search unit configured to obtain information that includes the character string from an index DB; a similarity calculation unit configured to calculate degree of similarity between the character string and searched information; and an output unit configured to output the searched information in descending order of the degree of similarity. In the information search apparatus, the character string information search unit includes a unit configured to, when the input character string contains a plurality of words, search an index DB, based on each word, that stores words and occurrence position information of the words to obtain a distance between occurrence positions of the words, and the similarity calculation unit includes a unit configured to calculate the degree of similarity based on the distance between occurrence positions of the words.

Claims

1. An information search apparatus comprising:

a character string input unit configured to obtain a character string from a client;

a character string information search unit configured to obtain information that includes the character string from an index DB;

a similarity calculation unit configured to calculate degree of similarity between the character string and searched information; and

an output unit configured to output the searched information in descending order of the degree of similarity, wherein

the character string information search unit includes a unit configured to, when the input character string contains a plurality of words, search an index DB, based on each word, that stores words and occurrence position information of the words to obtain a distance between occurrence positions of the words, and

the similarity calculation unit includes a unit configured to calculate the degree of similarity based on the distance between occurrence positions of the words.

2. The information search apparatus as claimed in claim 1, wherein the index DB holds the word and sentence-based occurrence position information of the word'"'"' in the document.

3. The information search apparatus as claimed in claim 1, wherein the index DB holds the word and sentence-based occurrence position information of the word in the document, and the occurrence position information is represented as a bit sequence,

the character string information search unit includes a unit configured to search the index DB to obtain the occurrence position of the word as the bit sequence, and

the similarity calculation unit includes a unit configured to obtain the degree of similarity by performing logical calculation of bits using the bit sequence of the occurrence position information of the index DB.

4. The information search apparatus as claimed in claim 1, further comprising:

a character string selection unit configured, when the input character string is composed of a plurality of words, to refer to a proximity unconsidered word list storing unit that stores words for which proximity is not considered, and to determine that the word is one for which proximity is not considered when the word exists in the proximity unconsidered word list storing unit,

wherein the character string information search unit includes a unit configured to search the index DB assuming that the word exists in every sentence as to the word determined to be one for which proximity is not considered by the character string selection unit.

5. The information search apparatus as claimed in claim 1, the character string information search unit further comprising:

an adjacency check unit configured, when the index DB stores sentence-based occurrence position information of each word, to search the index DB based on a plurality of words obtained from the input character string, detect an ID of a sentence in which the plurality of words exist, and search a document storing DB for the sentence corresponding to the ID, and, output the search result to the similarity calculation unit only when the sentence includes the input character string.

15. An information search program for causing a computer to function as each unit included in the information search apparatus as claimed in any one of claims 1-7.

16. A computer readable recording medium that stores the information search program as claimed in claim 15.

6. An information search apparatus comprising:

a character string input unit configured to obtain a character string from a client;

a character string information search unit configured to obtain information on a document including the character string from an index DB that stores sentence-based word occurrence position information in the document for each word;

a similarity calculation unit configured to calculate degree of similarity between the character string and the document; and

an output unit configured to output information of the document in descending order of the degree of similarity, wherein

the character string information search unit includes a unit configured to, when the input character string includes a plurality of words, search the index DB based on each word to obtain sentence-based occurrence position information of each word for each document, and

the similarity calculation unit includes a unit configured to calculate the degree of similarity between each document and the character string based on degree of sentence-based co-occurrence of the plurality of words in each document.

7. The information search apparatus as claimed in claim 6, wherein the similarity calculation unit obtains, for a document, the number of sentences in which the plurality words co-occur as the degree of the co-occurrence in the document.

8. An information search method in an apparatus for obtaining a character string from a client, obtaining information that includes the character string from an index DB, calculating degree of similarity between the character string and searched information, and outputting the searched information in descending order of the degree of similarity, the information search method comprising:

a character string information search step in which, when the input character string contains a plurality of words, a character string information search unit searches an index DB, based on each word, that stores words and occurrence position information of the words to obtain a distance between occurrence positions of the words, and

a step in which a similarity calculation unit calculates the degree of similarity based on the distance between occurrence positions of the words.

9. The information search method as claimed in claim 8, wherein the index DB holds the word and sentence-based occurrence position information of the word in the document.

10. The information search method as claimed in claim 8, wherein, when the index DB holds the word and sentence-based occurrence position information of the word in the document, and the occurrence position information is represented as a bit sequence,

in the character string information search step, the character string information search unit searches the index DB to obtain the occurrence position information of the word as the bit sequence, and

in the similarity calculation step, the similarity calculation unit obtains the degree of similarity by performing logical calculation of bits using the bit sequence of the occurrence position information of the index DB.

11. The information search method as claimed in claim 8, further comprising:

a character string selection step for, when the input character string is composed of a plurality of words, referring to a proximity unconsidered word list storing unit that stores words for which proximity is not considered to determine that the word is one for which proximity is not considered when the word exists in the proximity unconsidered word list storing unit,

wherein, in the character string information search step, the character string information search unit searches the index DB assuming that the word exists in every sentence as to the word determined to be one for which proximity is not considered in the character string selection step.

12. The information search method as claimed in claim 8, wherein, in the character string information search step,

when the index DB stores sentence-based occurrence position information of each word, the character string information search unit searches the index DB based on a plurality of words obtained from the input character string, detects an ID of a sentence in which the plurality of words exist, and searches a document storing DB for the sentence corresponding to the ID, and, outputs the search result to the similarity calculation unit only when the sentence includes the input character string.

13. An information search method executed by an information search apparatus, the information search apparatus comprising:

a character string input unit configured to obtain a character string from a client;

a character string information search unit configured to obtain information on a document including the character string from an index DB that stores sentence-based word occurrence position information in the document for each word;

a similarity calculation unit configured to calculate degree of similarity between the character string and the document; and

an output unit configured to output searched information of the document in descending order of the degree of similarity, the information search method comprising;

a character string information search step in which, when the input character string includes a plurality of words, the character string information search unit searches the index DB based on each word to obtain sentence-based occurrence position information of each word for each document, and

a similarity calculation step in which the similarity calculation unit calculates the degree of similarity between each document and the character string based on degree of sentence-based co-occurrence of the plurality of words in each document.

14. The information search method as claimed in claim 13, wherein the similarity calculation unit obtains, for a document, the number of sentences in which the plurality words co-occur as the degree of the co-occurrence in the document.