Similarity calculation device and similarity calculation program

• US 20060294060A1
• Filed: 03/29/2004
• Published: 12/28/2006
• Est. Priority Date: 09/30/2003
• Status: Abandoned Application

• Current Assignee: Intellectual Property Bank Corp.
• Original Assignee: Intellectual Property Bank Corp.
• Inventors: Masuyama, Hiroaki
• Application Number:
  US10/573,778
• Publication Number:
  US 20060294060A1
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 16/3346 using probabilistic model

Abstract

There is provided a similarity calculation device for calculating an index for judging technical similarity between technical document groups consisting of technical documents. The similarity calculation device includes: technical document group input means (365) for inputting a first technical document group and a second technical document group to be compared; technical information input means (371) for inputting technical information; cluster analysis means (380) for searching technical documents contained in the first technical document group and the second technical document group and including the technical information which has been input and decomposing the searched technical documents into a cluster for each technical information; similarity calculation means (380) for calculating the ratio of the number of mixed clusters including the technical documents of both of the first technical document group and the second technical document group against the total number of clusters obtained as the cluster decomposition; and output means (365) for outputting the similarity calculated.

Claims

1. A similarity calculation device, which calculates an index for judging technical similarity between a first technical document group and a second technical document group, each comprising patent documents, technical reports, or other technical documents, characterized in comprising:

technical document group input means for inputting the first technical document group and the second technical document group for comparison;

technical information input means for inputting technical information such as keywords or IPC symbols;

cluster analysis means for retrieving technical documents containing the input technical information from technical documents contained in the first technical document group and the second technical document group, and for clustering the retrieved technical documents by each technical information;

similarity calculation means for calculating, as the similarity, the ratio of the number of intermixed clusters containing technical documents of both the first technical document group and the second technical document group, to the total number of clusters obtained as a result of the cluster analysis; and

,

output means for outputting the calculated similarity to recording means, to display means, or to communication means.

2. A similarity calculation device, which calculates an index for judging technical similarity between a first technical document group and a second technical document group, each comprising patent documents, technical reports, or other technical documents, characterized in comprising:

technical document group input means for inputting the first technical document group and the second technical document group for comparison;

technical information input means for inputting technical information such as keywords or IPC symbols;

cluster analysis means for retrieving technical documents containing the input technical information from technical documents contained in the first technical document group and the second technical document group, and for clustering the retrieved technical documents by each technical information;

similarity calculation means for calculating the total number of clusters obtained as a result of the cluster analysis and the number of intermixed clusters containing technical documents of both the first technical document group and the second technical document group, as well as for calculating the sum, over all intermixed clusters, of the product of a first correction value which takes a value according to the number of technical documents contained in each intermixed cluster and a second correction value which takes a value according to the state of mixing of technical documents of the first technical document group and the technical documents of the second technical document group in each intermixed cluster, and dividing the sum by the calculated total number of clusters to calculate the similarity; and

,

output means for outputting the calculated similarity to recording means, to display means, or to communication means.

3. A similarity calculation device, which calculates an index for judging technical similarity between a first technical document group and a second technical document group, each comprising patent documents, technical reports, or other technical documents, characterized in comprising:

technical document group input means for inputting the first technical document group and the second technical document group for comparison;

technical information input means for inputting technical information such as keywords or IPC symbols;

cluster analysis means for retrieving technical documents containing the input technical information from technical documents contained in the first technical document group and the second technical document group, and for clustering the retrieved technical documents by each technical information;

similarity calculation means for calculating the total number of clusters obtained as a result of the cluster analysis and the number of intermixed clusters containing technical documents of both the first technical document group and the second technical document group, as well as for calculating the sum, over all intermixed clusters, of a correction value proportional to the α

th power (where 0<

α

) of the number of technical documents in each cluster, and dividing the sum by the calculated total number of clusters to calculate the similarity; and

,

output means for outputting the calculated similarity to recording means, to display means, or to communication means.

4. A similarity calculation device, which calculates an index for judging technical similarity between a first technical document group and a second technical document group, each comprising patent documents, technical reports, or other technical documents, characterized in comprising:

technical document group input means for inputting the first technical document group and the second technical document group for comparison;

technical information input means for inputting technical information such as keywords or IPC symbols;

cluster analysis means for retrieving technical documents containing the input technical information from technical documents contained in the first technical document group and the second technical document group, and for clustering the retrieved technical documents by each technical information;

similarity calculation means for calculating the total number of clusters obtained as a result of the cluster analysis and the number of intermixed clusters containing technical documents of both the first technical document group and the second technical document group, as well as for calculating the sum, over all intermixed clusters, of a correction value obtained by dividing the α

th power (where 0<

α

) of the number of technical documents in each cluster by a standardizing factor, and dividing the sum by the calculated total number of clusters to calculate the similarity; and

,

output means for outputting the calculated similarity to recording means, to display means, or to communication means.

5. The similarity calculation device according to claim 4, wherein the standardizing factor is the average value of the number of technical documents in all clusters.

6. A similarity calculation device, which calculates an index for judging technical similarity between a first technical document group and a second technical document group, each comprising patent documents, technical reports, or other technical documents, characterized in comprising:

technical document group input means for inputting the first technical document group and the second technical document group for comparison;

technical information input means for inputting technical information such as keywords or IPC symbols;

cluster analysis means for retrieving technical documents containing the input technical information from technical documents contained in the first technical document group and the second technical document group, and for clustering the retrieved technical documents by each technical information;

similarity calculation means for calculating the total number of clusters obtained as a result of the cluster analysis and the number of intermixed clusters containing technical documents of both the first technical document group and the second technical document group, as well as for calculating the sum, over all intermixed clusters, of a correction value proportional to the γ

th power (where 0<

γ

) of the probability of retrieving the m technical documents from the first technical document group and the n technical documents from the second technical document group, in order to perform correction according to the probability of the number of technical documents of the first technical document group and the second technical document group contained in each intermixed cluster obtained as a result of the cluster analysis, and dividing the sum by the calculated total number of clusters to calculate the similarity; and

,

output means for outputting the calculated similarity to recording means, to display means, or to communication means.

7. A similarity calculation device, which calculates an index for judging technical similarity between a first technical document group and a second technical document group, each comprising patent documents, technical reports, or other technical documents, characterized in comprising:

technical document group input means for inputting the first technical document group and the second technical document group for comparison;

technical information input means for inputting technical information such as keywords or IPC symbols;

cluster analysis means for retrieving technical documents containing the input technical information from technical documents contained in the first technical document group and the second technical document group, and for clustering the retrieved technical documents by each technical information;

similarity calculation means for calculating the total number of clusters obtained as a result of the cluster analysis and the number of intermixed clusters containing technical documents of both the first technical document group and the second technical document group, as well as for calculating the sum, over all intermixed clusters, of a correction value obtained by dividing, by a standardizing factor, the γ

th power (where 0<

γ

) of the probability of retrieving the m technical documents from the first technical document group and the n technical documents from the second technical document group, in order to perform correction according to the probability of the number of technical documents of the first technical document group and the second technical document group contained in each intermixed cluster obtained as a result of the cluster analysis, and dividing the sum by the calculated total number of clusters to calculate the similarity; and

,

output means for outputting the calculated similarity to recording means, to display means, or to communication means.

8. The similarity calculation device according to claim 7, wherein the standardizing factor is the γ

th power (where 0<

γ

) of the maximum value of the probability of retrieving the m technical documents from the first technical document group and the n technical documents from the second technical document group.

9. A similarity calculation device, which calculates an index for judging technical similarity between a first technical document group and a second technical document group, each comprising patent documents, technical reports, or other technical documents, characterized in comprising:

technical document group input means for inputting the first technical document group and the second technical document group for comparison;

technical information input means for inputting technical information such as keywords or IPC symbols;

cluster analysis means for retrieving technical documents containing the input technical information from technical documents contained in the first technical document group and the second technical document group, and for clustering the retrieved technical documents by each technical information;

similarity calculation means for calculating the total number of clusters obtained as a result of the cluster analysis and the number of intermixed clusters containing technical documents of both the first technical document group and the second technical document group, as well as for calculating the sum, over all intermixed clusters, of a correction value proportional to the ζ

th power (where 0<

ζ

) of the ratio of a composition ratio N/M and an intermixing ratio n/m, for the composition ratio N/M of the number of technical documents N contained in the second technical document group to the number of technical documents M contained in the first technical document group and for the intermixing ratio n/m of the number of technical documents n of the second technical document group to the number of technical documents m of the first technical document group contained in each intermixed cluster obtained as a result of the cluster analysis, and dividing the sum by the calculated total number of clusters to calculate the similarity; and

,

output means for outputting the calculated similarity to recording means, to display means, or to communication means.

10. A similarity calculation device, which calculates an index for judging technical similarity between a first technical document group and a second technical document group, each comprising patent documents, technical reports, or other technical documents, characterized in comprising:

technical document group input means for inputting the first technical document group and the second technical document group for comparison;

technical information input means for inputting technical information such as keywords or IPC symbols;

cluster analysis means for retrieving technical documents containing the input technical information from technical documents contained in the first technical document group and the second technical document group, and for clustering the retrieved technical documents by each technical information;

similarity calculation means for calculating the total number of clusters obtained as a result of the cluster analysis and the number of intermixed clusters containing technical documents of both the first technical document group and the second technical document group, and calculating an expectation value for retrieving a technical document of the first technical document group by multiplying the probability of retrieving a technical document of the first technical document group from among a technical document group covering the first technical document group and the second technical document group by the number of technical documents contained in each intermixed cluster, and calculating as an expectation value difference the difference between the expectation value and the number of technical documents of the first technical document group contained in each intermixed cluster, as well as for calculating the sum, over all intermixed clusters, of a correction value obtained by setting the expectation value difference as negative exponent for an arbitrary constant ξ

(where 1<

ξ

), and dividing the sum by the calculated total number of clusters to calculate the similarity; and

output means for outputting the calculated similarity to recording means, to display means, or to communication means.

11. A similarity calculation device, which calculates an index for judging technical similarity between a first technical document group and a second technical document group, each comprising patent documents, technical reports, or other technical documents, characterized in comprising:

technical document group input means for inputting the first technical document group and the second technical document group for comparison;

technical information input means for inputting technical information such as keywords or IPC symbols;

cluster analysis means for retrieving technical documents containing the input technical information from technical documents contained in the first technical document group and the second technical document group, and for clustering the retrieved technical documents by each technical information;

similarity calculation means for calculating the total number of clusters obtained as a result of the cluster analysis and the number of intermixed clusters containing technical documents of both the first technical document group and the second technical document group, and calculating the expectation value for retrieving a technical document of the first technical document group by multiplying the probability of retrieving a technical document of the first technical document group from among a technical document group covering the first technical document group and the second technical document group by the number of technical documents contained in each intermixed cluster, and calculating as an expectation value difference the difference between the expectation value and the number of technical documents of the first technical document group contained in each intermixed cluster, as well as for calculating the sum, over all intermixed clusters, of a correction value obtained by dividing the expectation value difference by the number of technical documents in each intermixed cluster and setting the divided expectation value difference as negative exponent for an arbitrary constant ξ

(where 1<

ξ

), and then dividing the sum by the calculated total number of clusters to calculate the similarity; and

output means for outputting the calculated similarity to recording means, to display means, or to communication means.

12. A similarity calculation program for calculating an index for judging technical similarity between technical document groups, which operates by means of information processing means for a similarity calculation device comprising technical document group input means for inputting the technical document groups, technical information input means for inputting technical information such as keywords, cluster analysis means for performing cluster analysis of the technical document groups by the technical information, similarity calculation means for calculating the total number of clusters and the number of intermixed clusters and calculating the similarity, output means for outputting the calculated similarity, and information processing means capable of controlling the technical document group input means, the technical information input means, the cluster analysis means, the similarity calculation means, and the output means,

characterized in causing the information processing means to achieve:

a function, executed by the technical document group input means, for input of a first technical document group and a second technical document group for comparison;

a function, executed by the technical information input means, for input of the technical information such as keywords or IPC symbols;

a function, executed by the cluster analysis means, for retrieving technical documents containing the input technical information from technical documents contained in the first technical document group and the second technical document group, and for clustering the retrieved technical documents by each technical information;

a function, executed by the similarity calculation means, for calculating the total number of clusters obtained as a result of the cluster analysis and the number of intermixed clusters containing technical documents of both the first technical document group and the second technical document group, and for calculating, as the similarity, the ratio of the number of intermixed clusters, containing technical documents of both the first technical document group and the second technical document group, to the total number of clusters obtained as a result of the cluster analysis; and

a function, executed by the output means, for outputting the calculated similarity to recording means, to display means, or to communication means.

13. A similarity calculation program for calculating an index for judging technical similarity between technical document groups, which operates by means of information processing means for a similarity calculation device comprising technical document group input means for inputting the technical document groups, technical information input means for inputting technical information such as keywords, cluster analysis means for performing cluster analysis of the technical document groups by the technical information, similarity calculation means for calculating the total number of clusters and the number of intermixed clusters and calculating the similarity, output means for outputting the calculated similarity, and information processing means capable of controlling the technical document group input means, the technical information input means, the cluster analysis means, the similarity calculation means, and the output means,

characterized in causing the information processing means to achieve:

a function, executed by the technical document group input means, for input of a first technical document group and a second technical document group for comparison;

a function, executed by the technical information input means, for input of the technical information such as keywords or IPC symbols;

a function, executed by the cluster analysis means, for retrieving technical documents containing the input technical information from technical documents contained in the first technical document group and the second technical document group, and for clustering the retrieved technical documents by each technical information;

a function, executed by the similarity calculation means, for calculating the total number of clusters obtained as a result of the cluster analysis and the number of intermixed clusters containing technical documents of both the first technical document group and the second technical document group, as well as for calculating the sum, over all intermixed clusters, of the product of a first correction value which takes a value according to the number of technical documents contained in each intermixed cluster and a second correction value which takes a value according to the state of mixing of technical documents of the first technical document group and the technical documents of the second technical document group in each intermixed cluster, and dividing the sum by the calculated total number of clusters to calculate the similarity; and

a function, executed by the output means, for outputting the calculated similarity to recording means, to display means, or to communication means.

14. A similarity calculation program for calculating an index for judging technical similarity between technical document groups, which operates by means of information processing means for a similarity calculation device comprising technical document group input means for inputting the technical document groups, technical information input means for inputting technical information such as keywords, cluster analysis means for performing cluster analysis of the technical document groups by the technical information, similarity calculation means for calculating the total number of clusters and the number of intermixed clusters and calculating the similarity, output means for outputting the calculated similarity, and information processing means capable of controlling the technical document group input means, the technical information input means, the cluster analysis means, the similarity calculation means, and the output means,

characterized in causing the information processing means to achieve:

a function, executed by the technical document group input means, for input of a first technical document group and a second technical document group for comparison;

a function, executed by the technical information input means, for input of the technical information such as keywords or IPC symbols;

a function, executed by the cluster analysis means, for retrieving technical documents containing the input technical information from technical documents contained in the first technical document group and the second technical document group, and for clustering the retrieved technical documents by each technical information;

a function, executed by the similarity calculation means, for calculating the total number of clusters obtained as a result of the cluster analysis and the number of intermixed clusters containing technical documents of both the first technical document group and the second technical document group, as well as for calculating the sum, over all intermixed clusters, of a correction value proportional to the α

th power (where 0<

α

) of the number of technical documents in each cluster, and dividing the sum by the calculated total number of clusters to calculate the similarity; and

a function, executed by the output means, for outputting the calculated similarity to recording means, to display means, or to communication means.

15. A similarity calculation program for calculating an index for judging technical similarity between technical document groups, which operates by means of information processing means for a similarity calculation device comprising technical document group input means for inputting the technical document groups, technical information input means for inputting technical information such as keywords, cluster analysis means for performing cluster analysis of the technical document groups by the technical information, similarity calculation means for calculating the total number of clusters and the number of intermixed clusters and calculating the similarity, output means for outputting the calculated similarity, and information processing means capable of controlling the technical document group input means, the technical information input means, the cluster analysis means, the similarity calculation means, and the output means,

characterized in causing the information processing means to achieve:

a function, executed by the technical document group input means, for input of a first technical document group and a second technical document group for comparison;

a function, executed by the technical information input means, for input of the technical information such as keywords or IPC symbols;

a function, executed by the cluster analysis means, for retrieving technical documents containing the input technical information from technical documents contained in the first technical document group and the second technical document group, and for clustering the retrieved technical documents by each technical information;

a function, executed by the similarity calculation means, for calculating the total number of clusters obtained as a result of the cluster analysis and the number of intermixed clusters containing technical documents of both the first technical document group and the second technical document group, as well as for calculating the sum, over all intermixed clusters, of a correction value obtained by dividing the α

th power (where 0<

α

) of the number of technical documents in each cluster by a standardizing factor, and dividing the sum by the calculated total number of clusters to calculate the similarity; and

a function, executed by the output means, for outputting the calculated similarity to recording means, to display means, or to communication means.

16. The similarity calculation program according to claim 15, further causing the information processing means to achieve a function, executed by the similarity calculation means, for using, as the standardizing factor, the average value of the number of technical documents in all clusters.

17. A similarity calculation program for calculating an index for judging technical similarity between technical document groups, which operates by means of information processing means for a similarity calculation device comprising technical document group input means for inputting the technical document groups, technical information input means for inputting technical information such as keywords, cluster analysis means for performing cluster analysis of the technical document groups by the technical information, similarity calculation means for calculating the total number of clusters and the number of intermixed clusters and calculating the similarity, output means for outputting the calculated similarity, and information processing means capable of controlling the technical document group input means, the technical information input means, the cluster analysis means, the similarity calculation means, and the output means,

characterized in causing the information processing means to achieve:

a function, executed by the technical document group input means, for input of a first technical document group and a second technical document group for comparison;

a function, executed by the technical information input means, for input of the technical information such as keywords or IPC symbols;

a function, executed by the cluster analysis means, for retrieving technical documents containing the input technical information from technical documents contained in the first technical document group and the second technical document group, and for clustering the retrieved technical documents by each technical information;

a function, executed by the similarity calculation means, for calculating the total number of clusters obtained as a result of the cluster analysis and the number of intermixed clusters containing technical documents of both the first technical document group and the second technical document group, as well as for calculating the sum, over all intermixed clusters, of a correction value proportional to the γ

th power (where 0<

γ

) of the probability of retrieving the m technical documents from the first technical document group and the n technical documents from the second technical document group, in order to perform correction according to the probability of the number of technical documents of the first technical document group and the second technical document group contained in each intermixed cluster obtained as a result of the cluster analysis, and dividing the sum by the calculated total number of clusters to calculate the similarity; and

a function, executed by the output means, for outputting the calculated similarity to recording means, to display means, or to communication means.

18. A similarity calculation program for calculating an index for judging technical similarity between technical document groups, which operates by means of information processing means for a similarity calculation device comprising technical document group input means for inputting the technical document groups, technical information input means for inputting technical information such as keywords, cluster analysis means for performing cluster analysis of the technical document groups by the technical information, similarity calculation means for calculating the total number of clusters and the number of intermixed clusters and calculating the similarity, output means for outputting the calculated similarity, and information processing means capable of controlling the technical document group input means, the technical information input means, the cluster analysis means, the similarity calculation means, and the output means,

characterized in causing the information processing means to achieve:

a function, executed by the technical document group input means, for input of a first technical document group and a second technical document group for comparison;

a function, executed by the technical information input means, for input of the technical information such as keywords or IPC symbols;

a function, executed by the cluster analysis means, for retrieving technical documents containing the input technical information from technical documents contained in the first technical document group and the second technical document group, and for clustering the retrieved technical documents by each technical information;

a function, executed by the similarity calculation means, for calculating the total number of clusters obtained as a result of the cluster analysis and the number of intermixed clusters containing technical documents of both the first technical document group and the second technical document group, as well as for calculating the sum, over all intermixed clusters, of a correction value obtained by dividing, by a standardizing factor, the γ

th power (where 0<

γ

) of the probability of retrieving the m technical documents from the first technical document group and the n technical documents from the second technical document group, in order to perform correction according to the probability of the number of technical documents of the first technical document group and the second technical document group contained in each intermixed cluster obtained as a result of the cluster analysis, and dividing the sum by the calculated total number of clusters to calculate the similarity; and

a function, executed by the output means, for outputting the calculated similarity to recording means, to display means, or to communication means.

19. The similarity calculation program according to claim 18, further causing the information processing means to achieve a function, executed by the similarity calculation means, for using, as the standardizing factor, the γ

th power (where 0<

γ

) of the maximum value of the probability of retrieving the m technical documents from the first technical document group and the n technical documents from the second technical document group.

20. A similarity calculation program for calculating an index for judging technical similarity between technical document groups, which operates by means of information processing means for a similarity calculation device comprising technical document group input means for inputting the technical document groups, technical information input means for inputting technical information such as keywords, cluster analysis means for performing cluster analysis of the technical document groups by the technical information, similarity calculation means for calculating the total number of clusters and the number of intermixed clusters and calculating the similarity, output means for outputting the calculated similarity, and information processing means capable of controlling the technical document group input means, the technical information input means, the cluster analysis means, the similarity calculation means, and the output means,

characterized in causing the information processing means to achieve:

a function, executed by the technical document group input means, for input of a first technical document group and a second technical document group for comparison;

a function, executed by the technical information input means, for input of the technical information such as keywords or IPC symbols;

a function, executed by the cluster analysis means, for retrieving technical documents containing the input technical information from technical documents contained in the first technical document group and the second technical document group, and for clustering the retrieved technical documents by each technical information;

a function, executed by the similarity calculation means, for calculating the total number of clusters obtained as a result of the cluster analysis and the number of intermixed clusters containing technical documents of both the first technical document group and the second technical document group, as well as for calculating the sum, over all intermixed clusters, of a correction value proportional to the ζ

th power (where 0<

ζ

) of the ratio of a composition ratio N/M and an intermixing ratio n/m, for the composition ratio N/M of the number of technical documents N contained in the second technical document group to the number of technical documents M contained in the first technical document group and for the intermixing ratio n/m of the number of technical documents n of the second technical document group to the number of technical documents m of the first technical document group contained in each intermixed cluster obtained as a result of the cluster analysis, and dividing the sum by the calculated total number of clusters to calculate the similarity; and

a function, executed by the output means, for outputting the calculated similarity to recording means, to display means, or to communication means.

21. A similarity calculation program for calculating an index for judging technical similarity between technical document groups, which operates by means of information processing means for a similarity calculation device comprising technical document group input means for inputting the technical document groups, technical information input means for inputting technical information such as keywords, cluster analysis means for performing cluster analysis of the technical document groups by the technical information, similarity calculation means for calculating the total number of clusters and the number of intermixed clusters and calculating the similarity, output means for outputting the calculated similarity, and information processing means capable of controlling the technical document group input means, the technical information input means, the cluster analysis means, the similarity calculation means, and the output means,

characterized in causing the information processing means to achieve:

a function, executed by the technical document group input means, for input of a first technical document group and a second technical document group for comparison;

a function, executed by the technical information input means, for input of the technical information such as keywords or IPC symbols;

a function, executed by the cluster analysis means, for retrieving technical documents containing the input technical information from technical documents contained in the first technical document group and the second technical document group, and for clustering the retrieved technical documents by each technical information;

a function, executed by the similarity calculation means, for calculating the total number of clusters obtained as a result of the cluster analysis and the number of intermixed clusters containing technical documents of both the first technical document group and the second technical document group, and calculating an expectation value for retrieving a technical document of the first technical document group by multiplying the probability of retrieving a technical document of the first technical document group from among a technical document group covering the first technical document group and the second technical document group by the number of technical documents contained in each intermixed cluster, and calculating as an expectation value difference the difference between the expectation value and the number of technical documents of the first technical document group contained in each intermixed cluster, as well as for calculating the sum, over all intermixed clusters, of a correction value obtained by setting the expectation value difference as negative exponent for an arbitrary constant ξ

(where 1<

ξ

), and dividing the sum by the calculated total number of clusters to calculate the similarity; and

a function, executed by the output means, for outputting the calculated similarity to recording means, to display means, or to communication means.

22. A similarity calculation program for calculating an index for judging technical similarity between technical document groups, which operates by means of information processing means for a similarity calculation device comprising technical document group input means for inputting the technical document groups, technical information input means for inputting technical information such as keywords, cluster analysis means for performing cluster analysis of the technical document groups by the technical information, similarity calculation means for calculating the total number of clusters and the number of intermixed clusters and calculating the similarity, output means for outputting the calculated similarity, and information processing means capable of controlling the technical document group input means, the technical information input means, the cluster analysis means, the similarity calculation means, and the output means,

characterized in causing the information processing means to achieve:

a function, executed by the technical document group input means, for input of a first technical document group and a second technical document group for comparison;

a function, executed by the technical information input means, for input of the technical information such as keywords or IPC symbols;

a function, executed by the cluster analysis means, for retrieving technical documents containing the input technical information from technical documents contained in the first technical document group and the second technical document group, and for clustering the retrieved technical documents by each technical information;

a function, executed by the similarity calculation means, for calculating the total number of clusters obtained as a result of the cluster analysis and the number of intermixed clusters containing technical documents of both the first technical document group and the second technical document group, and calculating the expectation value for retrieving a technical document of the first technical document group by multiplying the probability of retrieving a technical document of the first technical document group from among a technical document group covering the first technical document group and the second technical document group by the number of technical documents contained in each intermixed cluster, and calculating as an expectation value difference the difference between the expectation value and the number of technical documents of the first technical document group contained in each intermixed cluster, as well as for calculating the sum, over all intermixed clusters, of a correction value obtained by dividing the expectation value difference by the number of technical documents in each intermixed cluster and setting the divided expectation value difference as negative exponent for an arbitrary constant ξ

(where 1<

ξ

), and then dividing the sum by the calculated total number of clusters to calculate the similarity; and

a function, executed by the output means, for outputting the calculated similarity to recording means, to display means, or to communication means.

23. A similarity calculation method for calculating an index for judging technical similarity between technical document groups, using a similarity calculation device comprising technical document group input means for inputting the technical document groups, technical information input means for inputting technical information such as keywords, cluster analysis means for performing cluster analysis of the technical document groups by the technical information, similarity calculation means for calculating the total number of clusters and the number of intermixed clusters and calculating the similarity, and output means for outputting the calculated similarity, comprising:

a process, executed by the technical document group input means, of inputting a first technical document group and a second technical document group for comparison;

a process, executed by the technical information input means, of inputting the technical information such as keywords or IPC symbols;

a process, executed by the cluster analysis means, of retrieving technical documents containing the input technical information from technical documents contained in the first technical document group and the second technical document group, and of clustering the retrieved technical documents by each technical information;

a process, executed by the similarity calculation means, of calculating the total number of clusters obtained as a result of the cluster analysis and the number of intermixed clusters containing technical documents of both the first technical document group and the second technical document group, and of calculating, as the similarity, the ratio of the number of intermixed clusters, containing technical documents of both the first technical document group and the second technical document group, to the total number of clusters obtained as a result of the cluster analysis; and

a process, executed by the output means, of outputting the calculated similarity to recording means, to display means, or to communication means.

24. A similarity calculation method for calculating an index for judging technical similarity between technical document groups, using a similarity calculation device comprising technical document group input means for inputting the technical document groups, technical information input means for inputting technical information such as keywords, cluster analysis means for performing cluster analysis of the technical document groups by the technical information, similarity calculation means for calculating the total number of clusters and the number of intermixed clusters and calculating the similarity, and output means for outputting the calculated similarity, comprising:

a process, executed by the technical document group input means, of inputting a first technical document group and a second technical document group for comparison;

a process, executed by the technical information input means, of inputting the technical information such as keywords or IPC symbols;

a process, executed by the cluster analysis means, of retrieving technical documents containing the input technical information from technical documents contained in the first technical document group and the second technical document group, and clustering the retrieved technical documents by each technical information;

a process, executed by the similarity calculation means, of calculating the total number of clusters obtained as a result of the cluster analysis and the number of intermixed clusters containing technical documents of both the first technical document group and the second technical document group, as well as calculating the sum, over all intermixed clusters, of the product of a first correction value which takes a value according to the number of technical documents contained in each intermixed cluster and a second correction value which takes a value according to the state of mixing of technical documents of the first technical document group and the technical documents of the second technical document group in each intermixed cluster, and dividing the sum by the calculated total number of clusters to calculate the similarity; and

a process, executed by the output means, of outputting the calculated similarity to recording means, to display means, or to communication means.

25. A similarity calculation method for calculating an index for judging technical similarity between technical document groups, using a similarity calculation device comprising technical document group input means for inputting the technical document groups, technical information input means for inputting technical information such as keywords, cluster analysis means for performing cluster analysis of the technical document groups by the technical information, similarity calculation means for calculating the total number of clusters and the number of intermixed clusters and calculating the similarity, and output means for outputting the calculated similarity, comprising:

a process, executed by the technical document group input means, of inputting a first technical document group and a second technical document group for comparison;

a process, executed by the technical information input means, of inputting the technical information such as keywords or IPC symbols;

a process, executed by the cluster analysis means, of retrieving technical documents containing the input technical information from technical documents contained in the first technical document group and the second technical document group, and clustering the retrieved technical documents by each technical information;

a process, executed by the similarity calculation means, of calculating the total number of clusters obtained as a result of the cluster analysis and the number of intermixed clusters containing technical documents of both the first technical document group and the second technical document group, as well as calculating the sum, over all intermixed clusters, of a correction value proportional to the α

th power (where 0<

α

) of the number of technical documents in each cluster, and dividing the sum by the calculated total number of clusters to calculate the similarity; and

a process, executed by the output means, of outputting the calculated similarity to recording means, to display means, or to communication means.

26. A similarity calculation method for calculating an index for judging technical similarity between technical document groups, using a similarity calculation device comprising technical document group input means for inputting the technical document groups, technical information input means for inputting technical information such as keywords, cluster analysis means for performing cluster analysis of the technical document groups by the technical information, similarity calculation means for calculating the total number of clusters and the number of intermixed clusters and calculating the similarity, and output means for outputting the calculated similarity, comprising:

a process, executed by the technical document group input means, of inputting a first technical document group and a second technical document group for comparison;

a process, executed by the technical information input means, of inputting the technical information such as keywords or IPC symbols;

a process, executed by the cluster analysis means, of retrieving technical documents containing the input technical information from technical documents contained in the first technical document group and the second technical document group, and clustering the retrieved technical documents by each technical information;

a process, executed by the similarity calculation means, of calculating the total number of clusters obtained as a result of the cluster analysis and the number of intermixed clusters containing technical documents of both the first technical document group and the second technical document group, as well as calculating the sum, over all intermixed clusters, of a correction value obtained by dividing the α

th power (where 0<

α

) of the number of technical documents in each cluster by a standardizing factor, and dividing the sum by the calculated total number of clusters to calculate the similarity; and

a process, executed by the output means, of outputting the calculated similarity to recording means, to display means, or to communication means.

27. The similarity calculation method according to claim 26, wherein the similarity calculation means use, as the standardizing factor, the average value of the number of technical documents in all clusters.

28. A similarity calculation method for calculating an index for judging technical similarity between technical document groups, using a similarity calculation device comprising technical document group input means for inputting the technical document groups, technical information input means for inputting technical information such as keywords, cluster analysis means for performing cluster analysis of the technical document groups by the technical information, similarity calculation means for calculating the total number of clusters and the number of intermixed clusters and calculating the similarity, and output means for outputting the calculated similarity, comprising:

a process, executed by the technical document group input means, of inputting a first technical document group and a second technical document group for comparison;

a process, executed by the technical information input means, of inputting the technical information such as keywords or IPC symbols;

a process, executed by the cluster analysis means, of retrieving technical documents containing the input technical information from technical documents contained in the first technical document group and the second technical document group, and clustering the retrieved technical documents by each technical information;

a process, executed by the similarity calculation means, of calculating the total number of clusters obtained as a result of the cluster analysis and the number of intermixed clusters containing technical documents of both the first technical document group and the second technical document group, as well as calculating the sum, over all intermixed clusters, of a correction value proportional to the γ

th power (where 0<

γ

) of the probability of retrieving the m technical documents from the first technical document group and the n technical documents from the second technical document group, in order to perform correction according to the probability of the number of technical documents of the first technical document group and the second technical document group contained in each intermixed cluster obtained as a result of the cluster analysis, and dividing the sum by the calculated total number of clusters to calculate the similarity; and

a process, executed by the output means, of outputting the calculated similarity to recording means, to display means, or to communication means.

29. A similarity calculation method for calculating an index for judging technical similarity between technical document groups, using a similarity calculation device comprising technical document group input means for inputting the technical document groups, technical information input means for inputting technical information such as keywords, cluster analysis means for performing cluster analysis of the technical document groups by the technical information, similarity calculation means for calculating the total number of clusters and the number of intermixed clusters and calculating the similarity, and output means for outputting the calculated similarity, comprising:

a process, executed by the technical document group input means, of inputting a first technical document group and a second technical document group for comparison;

a process, executed by the technical information input means, of inputting the technical information such as keywords or IPC symbols;

a process, executed by the cluster analysis means, of retrieving technical documents containing the input technical information from technical documents contained in the first technical document group and the second technical document group, and clustering the retrieved technical documents by each technical information;

a process, executed by the similarity calculation means, of calculating the total number of clusters obtained as a result of the cluster analysis and the number of intermixed clusters containing technical documents of both the first technical document group and the second technical document group, as well as calculating the sum, over all intermixed clusters, of a correction value obtained by dividing, by a standardizing factor, the γ

th power (where 0<

γ

) of the probability of retrieving the m technical documents from the first technical document group and the n technical documents from the second technical document group, in order to perform correction according to the probability of the number of technical documents of the first technical document group and the second technical document group contained in each intermixed cluster obtained as a result of the cluster analysis, and dividing the sum by the calculated total number of clusters to calculate the similarity; and

a process, executed by the output means, of outputting the calculated similarity to recording means, to display means, or to communication means.

30. The similarity calculation method according to claim 29, wherein the similarity calculation means use, as the standardizing factor, the γ

th power (where 0<

γ

) of the maximum value of the probability of retrieving the m technical documents from the first technical document group and the n technical documents from the second technical document group.

31. A similarity calculation method for calculating an index for judging technical similarity between technical document groups, using a similarity calculation device comprising technical document group input means for inputting the technical document groups, technical information input means for inputting technical information such as keywords, cluster analysis means for performing cluster analysis of the technical document groups by the technical information, similarity calculation means for calculating the total number of clusters and the number of intermixed clusters and calculating the similarity, and output means for outputting the calculated similarity, comprising:

a process, executed by the technical document group input means, of inputting a first technical document group and a second technical document group for comparison;

a process, executed by the technical information input means, of inputting the technical information such as keywords or IPC symbols;

a process, executed by the cluster analysis means, of retrieving technical documents containing the input technical information from technical documents contained in the first technical document group and the second technical document group, and clustering the retrieved technical documents by each technical information;

a process, executed by the similarity calculation means, of calculating the total number of clusters obtained as a result of the cluster analysis and the number of intermixed clusters containing technical documents of both the first technical document group and the second technical document group, as well as calculating the sum, over all intermixed clusters, of a correction value proportional to the ζ

th power (where 0<

ζ

) of the ratio of a composition ratio N/M and an intermixing ratio n/m, for the composition ratio N/M of the number of technical documents N contained in the second technical document group to the number of technical documents M contained in the first technical document group and for the intermixing ratio n/m of the number of technical documents n of the second technical document group to the number of technical documents m of the first technical document group contained in each intermixed cluster obtained as a result of the cluster analysis, and dividing the sum by the calculated total number of clusters to calculate the similarity; and

a process, executed by the output means, of outputting the calculated similarity to recording means, to display means, or to communication means.

32. A similarity calculation method for calculating an index for judging technical similarity between technical document groups, using a similarity calculation device comprising technical document group input means for inputting the technical document groups, technical information input means for inputting technical information such as keywords, cluster analysis means for performing cluster analysis of the technical document groups by the technical information, similarity calculation means for calculating the total number of clusters and the number of intermixed clusters and calculating the similarity, and output means for outputting the calculated similarity, comprising:

a process, executed by the technical document group input means, of inputting a first technical document group and a second technical document group for comparison;

a process, executed by the technical information input means, of inputting the technical information such as keywords or IPC symbols;

a process, executed by the cluster analysis means, of retrieving technical documents containing the input technical information from technical documents contained in the first technical document group and the second technical document group, and clustering the retrieved technical documents by each technical information;

a process, executed by the similarity calculation means, of calculating the total number of clusters obtained as a result of the cluster analysis and the number of intermixed clusters containing technical documents of both the first technical document group and the second technical document group, and calculating an expectation value for retrieving a technical document of the first technical document group by multiplying the probability of retrieving a technical document of the first technical document group from among a technical document group covering the first technical document group and the second technical document group by the number of technical documents contained in each intermixed cluster, and calculating as an expectation value difference the difference between the expectation value and the number of technical documents of the first technical document group contained in each intermixed cluster, as well as calculating the sum, over all intermixed clusters, of a correction value obtained by setting the expectation value difference as negative exponent for an arbitrary constant ξ

(where 1<

ξ

), and dividing the sum by the calculated total number of clusters to calculate the similarity; and

a process, executed by the output means, of outputting the calculated similarity to recording means, to display means, or to communication means.

33. A similarity calculation method for calculating an index for judging technical similarity between technical document groups, using a similarity calculation device comprising technical document group input means for inputting the technical document groups, technical information input means for inputting technical information such as keywords, cluster analysis means for performing cluster analysis of the technical document groups by the technical information, similarity calculation means for calculating the total number of clusters and the number of intermixed clusters and calculating the similarity, and output means for outputting the calculated similarity, comprising:

a process, executed by the technical document group input means, of inputting a first technical document group and a second technical document group for comparison;

a process, executed by the technical information input means, of inputting the technical information such as keywords or IPC symbols;

a process, executed by the cluster analysis means, of retrieving technical documents containing the input technical information from technical documents contained in the first technical document group and the second technical document group, and clustering the retrieved technical documents by each technical information;

a process, executed by the similarity calculation means, of calculating the total number of clusters obtained as a result of the cluster analysis and the number of intermixed clusters containing technical documents of both the first technical document group and the second technical document group, and calculating the expectation value for retrieving a technical document of the first technical document group by multiplying the probability of retrieving a technical document of the first technical document group from among a technical document group covering the first technical document group and the second technical document group by the number of technical documents contained in each intermixed cluster, and calculating as an expectation value difference the difference between the expectation value and the number of technical documents of the first technical document group contained in each intermixed cluster, as well as calculating the sum, over all intermixed clusters, of a correction value obtained by dividing the expectation value difference by the number of technical documents in each intermixed cluster and setting the divided expectation value difference as negative exponent for an arbitrary constant ξ

(where 1<

ξ

), and then dividing the sum by the calculated total number of clusters to calculate the similarity; and

a process, executed by the output means, of outputting the calculated similarity to recording means, to display means, or to communication means.