Weighting method for use in information extraction and abstracting, based on the frequency of occurrence of keywords and similarity calculations

• US 20020072895A1
• Filed: 01/03/2001
• Published: 06/13/2002
• Est. Priority Date: 11/18/1994
• Status: Active Grant

• Current Assignee: Mitsuteru Kataoka, Satoshi Matsuura, Takeshi Imanaka
• Original Assignee: Mitsuteru Kataoka, Satoshi Matsuura, Takeshi Imanaka
• Inventors: Matsuura, Satoshi, Kataoka, Mitsuteru, Imanaka, Takeshi
• Granted Patent: US 6,502,065 B2
• Time in Patent Office: Days
• US Class Current: 704/9
• CPC Class Codes: G06F 40/216 using statistical methods
• CPC Class Codes: G06F 40/284 Lexical analysis, e.g. tokenisation or collocates
• CPC Class Codes: G06F 40/30 Semantic analysis
• CPC Class Codes: G06F 40/35 Discourse or dialogue representation
• CPC Class Codes: G06F 40/40 Processing or translation of natural language natural language analysis G06F40/20; semantic analysis G06F40/30
• CPC Class Codes: G06F 40/53 Processing of non-Latin text kana-to-kanji conversion G06F40/129; vowelisation G06F40/232

Abstract

The primary object of the invention is to extract and display keywords as an information abstract that are significant and effective in describing a topic common to a plurality of units, when a large number of character string data sets divided into prescribed units are given. The invention comprises an input section for accepting an input of character string data divided into prescribed units, with each individual character represented by a character code, and an output section for displaying the result of information abstracting. Keywords contained in each of the prescribed units are extracted by a keyword extracting section from the character string data input from the input section, a score is calculated for each keyword by a score calculating section so that a higher score is given to a keyword extracted from a lager number of units, and on the basis of the thus calculated scores, keywords are selected by an abstracting section and are output as an information abstract to the output section.

Claims

1. An information abstracting method comprising the steps of:

accepting an input of character string data divided into prescribed units, with each individual character represented by a character code;

extracting a keyword for each of said prescribed units from said input character string data;

weighting said extracted keyword by taking into account a state of occurrence, in the other prescribed units, of keywords that are identical to said extracted. keyword;

selecting at least one keyword from said extracted keywords on the basis of the weighted result; and

outputting said selected keyword as an information abstract relating to said character string data.

15. An information abstracting method according to claim 1, wherein said extracted keyword is weighted by using at least one of the number of prescribed units from which the keyword to be weighted was extracted, the frequency of occurrence of said keyword in each prescribed unit, and the number of characters of said keyword.

29. An information abstracting method according to claim 1, 5, 15, or 19, wherein

said input character string data is stored in a prescribed work area, and

after outputting said information abstract, when a keyword is designated from among the keywords constituting said information abstract, all or part of said character string data containing said designated keyword is output by using said designated keyword.

38. An information abstracting method according to claim 1, 5, 15, or 19, wherein

an input of an arbitrary keyword is accepted, and

after outputting said information abstract, when data contents of a paragraph in said unit are updated and said input keyword is found in said updated data, then

the whole or part of said data containing said keyword is output or stored, or

information indicating the existence of said data containing said keyword is output or stored.

41. An information abstracting method according to claim 1, 5, 15, or 19, wherein

after outputting said information abstract, a keyword is designated from among the keywords constituting said output information abstract, and

when data contents of a paragraph in said unit are thereafter updated and said designated keyword is found in said updated data, then

the whole or part of said data containing said keyword is output or stored, or

information indicating the existence of said data containing said keyword is output or stored.

2. An information abstracting apparatus comprising:

input means for accepting an input of character string data divided into prescribed units, with each individual character represented by a character code;

keyword extracting means for extracting a keyword for each of said prescribed units from the character string data input from said input means;

weighting means for weighting said extracted keyword by taking into account a state of occurrence, in the other prescribed units, of keywords that are identical to said extracted keyword;

keyword selecting means for selecting at least one keyword from said extracted keywords on the basis of the weighted result; and

output means for outputting said selected keyword as an information abstract relating to said character string data.

16. An information abstracting apparatus according to claim 2, wherein said extracted keyword is weighted by using at least one of the number of prescribed units from which the keyword to be weighted was extracted, the frequency of occurrence of said keyword in each prescribed unit, and the number of characters of said keyword.

3. A weighting method comprising the steps of:

accepting an input of character string data divided into prescribed units, with each individual character represented by a character code;

extracting a keyword for each of said prescribed units from said input character string data; and

weighting said extracted keyword by taking into account the state of occurrence, in the other prescribed units, of keywords that are identical to said extracted keyword.

17. A weighting method according to claim 3, wherein said extracted keyword is weighted by using at least one of the number of prescribed units from which the keyword to be weighted was extracted, the frequency of occurrence of said keyword in each prescribed unit, and the number of characters of said keyword.

4. A teletext broadcast receiving apparatus comprising:

teletext broadcast receiving means for receiving a teletext broadcast;

channel storing means for storing a plurality of channels of prescribed programs;

keyword extracting means for extracting a keyword from each of said prescribed programs received by said teletext broadcast receiving means on said channels stored in said channel storing means;

weighting means for weighting said extracted keyword by taking into account a state of occurrence, in the other prescribed programs, of keywords that are identical to said extracted keyword;

keyword selecting means for selecting keywords from said extracted keywords on the basis of the weighted result; and

display means for displaying all or part of said selected keywords as an information abstract relating to said teletext broadcast.

18. A teletext broadcast receiving apparatus according to claim 4, wherein said extracted keyword is weighted by using at least one of the number of prescribed programs from which the keyword to be weighted was extracted, the frequency of occurrence of said keyword in each prescribed program, and the number of characters of said keyword.

5. An information abstracting method comprising the steps of:

accepting an input of character string data divided into prescribed units each subdivided into prescribed paragraphs, with each individual character represented by a character code;

extracting a keyword for each paragraph in each of said prescribed units from said input character string data;

generating a keyword association by associating one keyword with another among keywords obtained from the same paragraph;

weighting said extracted keyword by taking into account a state of occurrence, in the other prescribed units, of keywords that are identical to said extracted keyword, and also weighting said generated keyword association by taking into account a state of occurrence, in the other prescribed paragraphs, of keyword associations that are identical to said generated keyword association;

selecting keywords and keyword associations from said extracted keywords and said generated keyword associations on the basis of the weighted results; and

outputting said selected keywords and keyword associations as an information abstract relating to said character string data.

19. An information abstracting method according to claim 5, wherein

said extracted keyword is weighted by using at least one of the number of prescribed units from which the keyword to be weighted was extracted, the frequency of occurrence of said keyword in each prescribed unit, and the number of characters of said keyword, and

said generated keyword is weighted by using at least one of the number of prescribed paragraphs from which the keyword association to be weighted was obtained, the frequency of occurrence of keywords constituting said keyword association in each prescribed paragraph, and the number of characters of the keywords constituting said keyword association.

44. An information abstracting method according to claim 5, wherein a plurality of mutually associated keywords are arranged essentially in one cluster and the thus clustered keywords are output as said information abstract.

46. An information abstracting method according to claim 5, wherein a plurality of mutually associated keywords are output as said information abstract for display on said display means in such a manner that, of said plurality of keywords, the first keyword is displayed in a reference position and the subsequent keywords are each displayed on a new line by being displaced by a prescribed number of characters to the right with respect to said reference position, thus displaying said plurality of mutually associated keywords as a cluster when viewed.

6. An information abstracting apparatus comprising:

input means for accepting an input of character string data divided into prescribed units each subdivided into prescribed paragraphs, with each individual character represented by a character code;

keyword extracting means for extracting a keyword for each paragraph in each of said prescribed units from the character string data input from said input means;

keyword associating means for generating a keyword association by associating one keyword with another among keywords obtained from the same paragraph;

weighting means for weighting said extracted keyword by taking into account a state of occurrence, in the other prescribed units, of keywords that are identical to said extracted keyword, and for weighting said generated keyword association by taking into account a state of occurrence, in the other prescribed paragraphs, of keyword associations that are identical to said generated keyword association;

selecting means for selecting keywords and keyword associations from said extracted keywords and said generated keyword associations on the basis of the weighted results; and

output means for outputting said selected keywords and keyword associations as an information abstract relating to said character string data.

20. An information abstracting apparatus according to claim 6, wherein said weighting means weights

said extracted keyword by using at least one of the number of prescribed units from which the keyword to be weighted was extracted, the frequency of occurrence of said keyword in each prescribed unit, and the number of characters of said keyword, and

said generated keyword by using at least one of the number of prescribed paragraphs from which the keyword association to be weighted was obtained, the frequency of occurrence of keywords constituting said keyword association in each prescribed paragraph, and the number of characters of the keywords constituting said keyword association.

7. A weighting method comprising the steps of:

accepting an input of character string data divided into prescribed units each subdivided into prescribed paragraphs, with each individual character represented by a character code;

extracting a keyword for each paragraph in each of said prescribed units from said input character string data;

generating a keyword association by associating one keyword with another among keywords obtained from the same paragraph; and

weighting said extracted keyword by taking into account a state of occurrence, in the other prescribed units, of keywords that are identical to said extracted keyword, and also weighting said generated keyword association by taking into account a state of occurrence, in the other prescribed paragraphs, of keyword associations that are identical to said generated keyword association.

21. A weighting method according to claim 7, wherein

said extracted keyword is weighted by using at least one of the number of prescribed units from which the keyword to be weighted was extracted, the frequency of occurrence of said keyword in each prescribed unit, and the number of characters of said keyword, and

said generated keyword is weighted by using at least one of the number of prescribed paragraphs from which the keyword association to be weighted was obtained, the frequency of occurrence of keywords constituting said keyword association in each prescribed paragraph, and the number of characters of the keywords constituting said keyword association.

8. A teletext broadcast receiving apparatus comprising:

teletext broadcast receiving means for receiving a teletext broadcast;

channel storing means for storing a plurality of channels of prescribed programs;

keyword extracting means for extracting a keyword from each of said prescribed programs received by said teletext broadcast receiving means on said channels stored in said channel storing means;

keyword associating means for generating a keyword association by associating one keyword with another among keywords obtained from the same paragraph in the same program;

weighting means for weighting said extracted keyword by taking into account a state of occurrence, in the other prescribed programs, of keywords that are identical to said extracted keyword, and for weighting said generated keyword association by taking into account a state of occurrence, in the other prescribed paragraphs, of keyword associations that are identical to said generated keyword association;

selecting means for selecting keywords and keyword associations from said extracted keywords and said generated keyword associations on the basis of the weighted results; and

display means for displaying all or part of said selected keywords and keyword associations as an information abstract relating to said teletext broadcast.

22. A teletext broadcast receiving apparatus according to claim 8, wherein said weighting means weights

said extracted keyword by using at least one of the number of prescribed programs from which the keyword to be weighted was extracted, the frequency of occurrence of said keyword in each prescribed program, and the number of characters of said keyword, and

said generated keyword by using at least one of the number of prescribed paragraphs from which the keyword association to be weighted was obtained, the frequency of occurrence of keywords constituting said keyword association in each prescribed paragraph, and the number of characters of the keywords constituting said keyword association.

9. An information abstracting apparatus comprising:

input means for accepting an input of character string data divided into prescribed units, with each individual character represented by a character code;

keyword extracting means for extracting a keyword for each of said prescribed units from said input character string data;

similarity calculating means for calculating similarity between keywords thus extracted;

weighting means for weighting said extracted keyword by taking into account a state of occurrence, in the other prescribed units, of keywords that are identical or similar to said extracted keyword;

keyword selecting means for selecting keywords from said extracted keywords on the basis of the weighted result; and

output means for outputting said selected keywords as an information abstract relating to said character string data.

35. An information abstracting apparatus according to claim 9, wherein said keyword is weighted by using at least one of the number of units from which keywords whose similarity with the keyword to be weighted is greater than a predetermined reference were extracted, the frequency of occurrence in each prescribed unit of keywords whose similarity with said keyword is greater than said predetermined reference, and the number of characters of said keyword.

10. A weighting method comprising the steps of:

accepting an input of character string data divided into prescribed units, with each individual character represented by a character code;

extracting a keyword for each of said prescribed units from said input character string data;

calculating similarity between keywords thus extracted; and

weighting said extracted keyword by taking into account a state of occurrence, in the other prescribed units, of keywords that are identical or similar to said extracted keyword.

36. A weighting method according to claim 10, wherein said keyword is weighted by using at least one of the number of units from which keywords whose similarity with the keyword to be weighted is greater than a predetermined reference were extracted, the frequency of occurrence in each prescribed unit of keywords whose similarity with said keyword is greater than said predetermined reference, and the number of characters of said keyword.

11. A teletext broadcast receiving apparatus comprising:

teletext broadcast receiving means for receiving a teletext broadcast;

channel storing means for storing a plurality of channels of prescribed programs;

keyword extracting means for extracting a keyword from each of said prescribed programs received by said teletext broadcast receiving means on said channels stored in said channel storing means;

similarity calculating mean'"'"'s for calculating similarity between keywords thus extracted;

weighting means for weighting said extracted keyword by taking into account a state of occurrence, in the other prescribed programs, of keywords that are identical or similar to said extracted keyword;

keyword selecting means for selecting keywords from said extracted keywords on the basis of the weighted result; and

display means for displaying all or part of said selected keywords as an information abstract relating to said teletext broadcast.

31. A teletext broadcast receiving apparatus according to claim 4, 8, 11, 14, 18, 22, 25, or 28, further including

keyword designating means for designating a keyword, and

a work area for storing data of said teletext broadcast received by said teletext broadcast receiving means, wherein

after said information abstract is displayed by said display means, when a keyword is designated by said keyword designating means from among the keywords constituting said displayed information abstract, all or part of said teletext broadcast data containing said designated keyword is displayed by said display means by using said designated keyword.

32. An information abstracting apparatus according to claim 12, wherein the larger the number of paragraphs containing said keyword association constituted by the keywords having said larger similarity between the keywords is, the larger the weight which is to be assinged to the keyword association becomes.

33. A weighting method according to claim 13, wherein the larger the number of paragraphs containing said keyword association constituted by the keywords having said larger similarity between the keywords is, the larger the weight which is to be assinged to the keyword association becomes.

34. A teletext broadcast receiving apparatus according to claim 14, wherein the larger the number of paragraphs containing said keyword association constituted by the keywords having said larger similarity between the keywords is, the larger the weight which is to be assinged to the keyword association becomes.

37. A teletext broadcast receiving apparatus according to claim 11, wherein said keyword is weighted by using at least one of the number of units from which keywords whose similarity with the keyword to be weighted is greater than a predetermined reference were extracted, the frequency of occurrence in each prescribed unit of keywords whose similarity with said keyword is greater than said predetermined reference, and the number of characters of said keyword.

40. A teletext broadcast receiving apparatus according to claim 4, 8, 11, 14, 18, 22, 25, or 28, further including

keyword input means for inputting an arbitrary keyword, and

data storing means for storing data, wherein

after said information abstract is displayed by said display means, when data contents of a paragraph in said program are updated and when said input keyword is found in said updated data, then

the whole or part of said data containing said keyword is displayed by said display means or stored in said data storing means, or

information indicating the existence of said data containing said keyword is displayed by said display means or stored in said data storing means.

43. A teletext broadcast receiving apparatus according to claim 4, 8, 11, 14, 18, 22, 25, and 28, further including

keyword designating means for designating a keyword, and

data storing means for storing data, wherein

after said information abstract is displayed by said display means, when a keyword is designated by said keyword designating means from among the keywords constituting said displayed information abstract and when data contents of a paragraph in said program are thereafter updated and said designated keyword is found in said updated data, then

the whole or part of said data containing said keyword is displayed by said display means or stored in said data storing means, or

information indicating the existence of said data containing said keyword is displayed by said display means or stored in said data storing means.

48. An information abstracting apparatus according to claim 12, wherein said keyword is weighted by using at least one of the number of units from which keywords whose similarity with the keyword to be weighted is greater than a predetermined reference were extracted, the frequency of occurrence in each prescribed unit of keywords whose similarity with said keyword is greater than said predetermined reference, and the number of characters of said keyword.

49. A weighting method according to claim 13, wherein said keyword is weighted by using at least one of the number of units from which keywords whose similarity with the keyword to be weighted is greater than a predetermined reference were extracted, the frequency of occurrence in each prescribed unit of keywords whose similarity with said keyword is greater than said predetermined reference, and the number of characters of said keyword.

50. A teletext broadcast receiving apparatus according to claim 14, wherein said keyword is weighted by using at least one of the number of units from which keywords whose similarity with the keyword to be weighted is greater than a predetermined reference were extracted, the frequency of occurrence in each prescribed unit of keywords whose similarity with said keyword is greater than said predetermined reference, and the number of characters of said keyword.

12. An information abstracting apparatus comprising:

input means for accepting an input of character string data divided into prescribed units each subdivided into prescribed paragraphs, with each individual character represented by a character code;

keyword extracting means for extracting a keyword for each paragraph in each of said prescribed units from said character string data input from said input means;

keyword associating means for generating a keyword association by associating one keyword with another among keywords obtained from the same paragraph;

similarity calculating means for calculating similarity between keywords thus extracted, on the basis of a plurality of factors including said keyword association;

weighting means for weighting said extracted keyword by taking into account a state of occurrence, in the other prescribed units, of keywords that are identical or similar to said extracted keyword, and for weighting said generated keyword association by taking into account a state of occurrence, in the other prescribed paragraphs, of keyword associations that are identical to said generated keyword association;

selecting means for selecting keywords and keyword associations from said extracted keywords and said generated keyword associations on the basis of the weighted results; and

outputting said selected keywords and keyword associations as an information abstract relating to said character string data.

30. An information abstracting apparatus according to claim 2, 6, 9, 12, 16, 20, 23, or 26, further including keyword designating means for designating a keyword, and

a work area for storing said character string data input from said input means, wherein

after said information abstract is output to said output means, when a keyword is designated by said keyword designating means from among the keywords constituting said output information abstract, all or part of said character string data containing said designated keyword is output by said output means by using said designated keyword.

39. An information abstracting apparatus according to claim 2, 6, 9, 12, 16, 20, 23, or 26, further including

keyword input means for inputting an arbitrary keyword, and

data storing means for storing data, wherein

after said information abstract is output by said output means, when data contents of a paragraph in said unit are updated and said input keyword is found in said updated data, then

the whole or part of said data containing said keyword is output by said output means or stored in said data storing means, or

information indicating the existence of said data containing said keyword is output by said output means or stored in said data storing means.

42. An information abstracting apparatus according to claim 2, 6, 9, 12, 16, 20, 23, or 26, further including

keyword designating means for designating a keyword, and

data storing means for storing data, wherein

after said information abstract is output by said output means, when a keyword is designated by said keyword designating means from among the keywords constituting said output information abstract and when data contents of a paragraph in said unit are thereafter updated and said designated keyword is found in said updated data, then

the whole or part of said data containing said keyword is output by said output means or stored in said data storing means, or

information indicating the existence of said data containing said keyword is output by said output means or stored in said data storing means.

45. An information abstracting apparatus according to claim 6, 12, 23, or 26, wherein a plurality of mutually associated keywords are arranged essentially in one cluster and the thus clustered keywords are output as said information abstract by said output means.

47. An information abstracting apparatus according to claim 6, 12, 23, or 26, wherein

said output means includes a display section for displaying a plurality of mutually associated keywords as said information abstract, and

a display control section for displaying said plurality of mutually associated keywords as a cluster when viewed, in such a manner that, of said plurality of keywords, the first keyword is displayed in a reference position and the subsequent keywords are each displayed on a new line by being displaced by a prescribed number of characters to the right with respect to said reference position.

13. A weighting method comprising the steps of:

accepting an input of character string data divided into prescribed units each subdivided into prescribed paragraphs, with each individual character represented by a character code;

extracting a keyword for each paragraph in each of said prescribed units from said input character string;

generating a keyword association by associating one keyword with another among keywords obtained from the same paragraph;

calculating similarity between keywords thus extracted, on the basis of a plurality of factors including said keyword association; and

weighting said extracted keyword by taking into account a state of occurrence, in the other prescribed units, of keywords that are identical or similar to said extracted keyword, and also weighting said generated keyword association by taking into account a state of occurrence, in the other prescribed paragraphs, of keyword associations that are identical to said generated keyword association.

14. A teletext broadcast receiving apparatus comprising:

teletext broadcast receiving means for receiving a teletext broadcast;

channel storing means for storing a plurality of channels of prescribed programs;

keyword extracting means for extracting a keyword from each of said prescribed programs received by said teletext broadcast receiving means on said channels stored in said channel storing means;

keyword associating means for generating a keyword association by associating one keyword with another among keywords obtained from the same paragraph in the same program;

similarity calculating means for calculating similarity between keywords thus extracted, on the basis of a plurality of factors including said keyword association;

weighting means for weighting said extracted keyword by taking into account a state of occurrence, in the other prescribed programs, of keywords that are identical or similar to said extracted keyword, and for weighting said generated keyword association by taking into account a state of occurrence, in the other prescribed paragraphs, of keyword associations that are identical to said generated keyword association;

selecting means for selecting keywords and keyword associations from said extracted keywords and said generated keyword associationson the basis of the weighted results; and

display means for displaying all or part of said selected keywords and keyword associations as an information abstract relating to said teletext broadcast.

23. An information abstracting apparatus comprising:

input means for accepting an input of character string data divided into prescribed units each subdivided into prescribed paragraphs, with each individual character represented by a character code;

keyword extracting means for extracting a keyword for each paragraph in each of said prescribed units from the character string data input from said input means;

keyword associating means for generating a keyword association by associating one keyword with another among keywords obtained from the same paragraph;

weighting means for weighting said generated keyword association by taking into account a state of occurrence, in the other prescribed paragraphs, of keyword associations that are identical to said generated keyword association;

selecting means for selecting keyword associations from said generated keyword associations on the basis of the weighted result; and

output means for outputting an information abstract, generated based on the selection results, relating to said character string data.

24. A weighting method comprising the steps of:

accepting an input of character string data divided into prescribed units each subdivided into prescribed paragraphs, with each individual character represented by a character code;

extracting a keyword for each paragraph in each of said prescribed units from said input character string data;

generating a keyword association by associating one keyword with another among keywords obtained from the same paragraph; and

weighting said generated keyword association by taking into account a state of occurrence, in the other prescribed paragraphs, of keyword associations that are identical to said generated keyword association.

25. A teletext broadcast receiving apparatus comprising:

teletext broadcast receiving means for receiving a teletext broadcast;

channel storing means for storing a plurality of channels of prescribed programs;

keyword extracting means for extracting a keyword from each of said prescribed programs received by said teletext broadcast receiving means on said channels stored in said channel storing means;

keyword associating means for generating a keyword association by associating one keyword with another among keywords obtained from the same paragraph in the same program;

weighting means for weighting said generated keyword association by taking into account a state of occurrence, in the other prescribed paragraphs, of keyword associations that are identical to said generated keyword association;

selecting means for selecting keyword associations from said generated keyword associations on the basis of the weighted result; and

display means for displaying an information abstract, generated based on the selection results, relating to said teletext broadcast.

26. An information abstracting apparatus comprising:

input means for accepting an input of character string data divided into prescribed units each subdivided into prescribed paragraphs, with each individual character represented by a character code;

keyword extracting means for extracting a keyword for each paragraph in each of said prescribed units from said character string data input from said input means;

keyword associating means for generating a keyword association by associating one keyword with another among keywords obtained from the same paragraph;

similarity calculating means for calculating similarity between keywords thus extracted;

keyword association/similarity calculating means for, by using said similarity calculated between keywords constituting said generated keyword association and keywords constituting another keyword association, calculating similarity between the keyword associations;

weighting means for weighting said generated keyword association by taking into account a state of occurrence, in the other prescribed paragraphs, of keyword associations that are identical or similar to said generated keyword association;

selecting means for selecting keyword associations from said generated keyword associations on the basis of the weighted result; and

outputting said selected keyword associations as an information abstract relating to said character string data.

27. A weighting method comprising the steps of:

accepting an input of character string data divided into prescribed units each subdivided into prescribed paragraphs, with each individual character represented by a character code;

extracting a keyword for each paragraph in each of said prescribed units from said input character string;

generating a keyword association by associating one keyword with another among keywords obtained from the same paragraph;

calculating similarity between keywords thus extracted;

by using said similarity calculated between keywords constituting said generated keyword association and keywords constituting another keyword association, calculating similarity between the keyword associations; and

weighting said generated keyword association by taking into account a state of occurrence, in the other prescribed paragraphs, of keyword associations that are identical or similar to said generated keyword association.

28. A teletext broadcast receiving apparatus comprising:

teletext broadcast receiving means for receiving a teletext broadcast;

channel storing means for storing a plurality of channels of prescribed programs;

keyword extracting means for extracting a keyword from each of said prescribed programs received by said teletext broadcast receiving means on said channels stored in said channel storing means;

keyword associating means for generating a keyword association by associating one keyword with another among keywords obtained from the same paragraph;

similarity calculating means for calculating similarity between keywords thus extracted;

keyword association/similarity calculating means for, by using said similarity calculated between keywords constituting said generated keyword association and keywords constituting another keyword association, calculating similarity between the keyword associations;

weighting means for weighting said generated keyword association by taking into account a state of occurrence, in the other prescribed paragraphs, of keyword associations that are identical or similar to said generated keyword association;

selecting means for selecting keyword associations from said generated keyword associations on the basis of the weighted result; and

display means for displaying all or part of said selected keyword associations as an information abstract relating to said teletext broadcast.