Fuzzy inference device

• US 5,434,955 A
• Filed: 04/19/1993
• Issued: 07/18/1995
• Est. Priority Date: 06/28/1990
• Status: Expired due to Fees

• Current Assignee: Omron Corporation
• Original Assignee: Omron Corporation
• Inventors: Kumamoto, Hiroshi
• Primary Examiner(s): Downs, Robert W.
• Application Number:
  US08/047,369
• Time in Patent Office: 820 Days
• Field of Search: 395/3, 395/11, 395/61, 395/900, 395/51
• US Class Current: 706/52
• CPC Class Codes: G06N 7/04 Physical realisation
• CPC Class Codes: Y10S 706/90 Fuzzy logic

Abstract

The present invention is carried out by modifying input data by the degree grade with respect to membership functions. The degree of fit measure is then used to obtain the information amount of each phenomena. A relational coefficient, which indicates the relatedness of a number of phenomena (for example, phenomena linked by an AND), is obtained. The degree of fit, information amount and relational coefficient are then used to determine the possibility of a conclusion. This scheme allows the user to enhance the accuracy of the information amount at the time the data are input. It also enables the user to attain an inference result with high discriminability based upon the relatedness of a number of phenomena with respect to a single conclusion. In another embodiment, the knowledge of expert users expressing the relationships between phenomena and conclusions is stored prior to use of the device. An inference device calculates the possibility of various conclusions and then calculates the clearnesses of the possibilities it has produced. As a result, the device exploits the user'"'"'s knowledge that a single phenomenon for which a single conclusion is to be drawn may have two or more distinct definitions; and these may be conjoined in an OR relationship or conjoined in an AND relationship. The accuracy of inferences is thus improved and the area in which inferences are applied is broadened.

Claims

1. A fuzzy inference apparatus comprising:

an input device for entering input data relating to phenomena;

a storage device for storing knowledge of expert users expressing relationships between phenomena and conclusions as a plurality of membership functions;

a grade calculating device for determining a grade measure for said input date with respect to each of said plurality of membership functions stored in said storage device;

a fuzzy information amount calculating device for calculating a fuzzy information amount for each phenomenon using said grade measures;

a relational coefficient calculating device for calculating a relational coefficient for each conclusion which expresses the relatedness of multiple of said phenomena and said conclusion using said grade measures; and

a possibility calculating device for performing fuzzy inferences on said phenomena to determine a possibility of a conclusion using said grade measures, said fuzzy information amounts and said relational coefficients.

2. A fuzzy inference apparatus, comprising:

an input device for entering input data relating to phenomena;

a storage device for storing knowledge of expert users expressing relationships between phenomena and conclusions as a plurality of membership functions, whereby said relationships can include a case in which a single phenomenon, for which a single conclusion is to be drawn, has two or more separate definitions which are conjoined in an OR relationship, said two or more definitions being represented by at least two membership functions;

a grade calculating device for calculating a grade measure of said input data with respect to each of said plurality of membership functions for a given conclusion, wherein when a single phenomenon, for which a conclusion is to be drawn, has two or more separate definitions which are conjoined in an OR relationship, a grade measure of said input data is produced for each of said two or more of membership functions representing said two or more definitions;

a fuzzy information amount calculating device for calculating a fuzzy information amount for each said phenomenon using said grade measures; and

a possibility calculating device for performing fuzzy inferences to determine a possibility of a conclusion using said grade measures and said fuzzy information amounts.

3. The fuzzy inference apparatus of claim 2, wherein said grade calculation performed by said grade calculation device is a MAX calculation.

4. The fuzzy inference apparatus of claim 3, wherein said plurality of membership functions in said storage device can include relationships in which various multiple phenomena are related to a single conclusion are conjoined in an OR relationship;

wherein said grade calculating device further produces a grade for each group of said phenomena which are conjoined in an OR relationship and wherein said possibility calculating device determines the possibility of a conclusion using said grade measures, said grade for each said group, and said fuzzy information amounts.

5. The fuzzy inference apparatus of claim 2, wherein said knowledge is stored in said storage device in a form which expresses that two or more definitions of said single phenomenon are in an OR relationship.

6. The fuzzy inference apparatus of claim 2, further comprising a clearness calculating means comprising:

a static information amount calculating device for calculating a static information amount for each phenomenon based on said plurality of membership functions;

a static calculating device for calculating the clearness of each phenomenon with respect to each conclusion using said static information amounts;

an adding device for calculating the clearness of each conclusion by adding together the clearnesses of the phenomena relating to said input data for a given conclusion; and

a clearness storage device for storing the clearness calculation.

7. A fuzzy inference apparatus comprising:

an input device for entering input data relating to phenomena;

a storage device for storing knowledge of expert users which expresses relationships between phenomena and conclusions as a plurality of membership functions, wherein said knowledge can include relationships of multiple phenomena to a single conclusion which are conjoined in an OR relationship;

a grade calculating device for determining a grade measure for said input data with respect to each of said plurality of membership functions stored in said storage device and for determining a grade for each group of said phenomena which are conjoined in an OR relationship;

a fuzzy information amount calculating device for calculating a fuzzy information amount for each phenomenon using said grade measures; and

a possibility calculating device for calculating the possibility of a conclusion using said grade measures, said grade for each of said groups, and said fuzzy information amounts.

8. The fuzzy inference apparatus of claim 7, wherein said grade calculating device produces said grade measure using a MAX calculation.

9. The fuzzy inference apparatus of claim 7, wherein said storage device stores said knowledge in a form which expresses that various multiple phenomena about which a single conclusion is to be drawn are in an OR relationship.

10. A fuzzy inference apparatus comprising:

an input device for entering input data related to phenomena;

a storage device for storing knowledge of expert users expressing relationships between phenomena and conclusions as a plurality of membership functions, wherein said relationships include various multiple phenomena about which a single conclusion is to be drawn conjoined in an OR relationship and also include multiple phenomena and conclusions conjoined in an AND relationship;

a grade calculating device for determining a grade measure for said input data with respect to each of said plurality of membership functions, for determining a first grade for a group of phenomena conjoined in an OR relationship, and for determining a second grade for another group of phenomena conjoined in an AND relationship;

a fuzzy information amount calculating device for calculating the fuzzy information amount for each phenomenon using said grade measures; and

a possibility calculating device for calculating the possibility of a conclusion using said grade measures, said first grade, said second grade and said fuzzy information amounts.

11. The fuzzy inference apparatus of claim 10, wherein said grade calculating device determines said first grade for said group of phenomena conjoined in an OR relationship in a MAX calculation and determines said second grade for said group of phenomena conjoined in an AND relationship in a MIN calculation.

12. The fuzzy inference apparatus of claim 10, wherein said storage device stores said knowledge in a form which expresses said phenomena conjoined in an OR relationship and said phenomena conjoined in an AND relationship.

13. The fuzzy inference apparatus of claim 10, further comprising a clearness device which comprises:

a static information amount calculating device for calculating a static information amount for each phenomenon based on said membership functions;

a clearness calculating device for calculating the clearness of each phenomenon with respect to each conclusion using said static information amounts; and

an adding device for calculating a clearness of each said conclusion by adding together said clearnesses of said phenomena relating to said input data for a given conclusion; and

a clearness storage device for storing the clearness calculation.