JPH04241627A - Method for utilizing data base as knowledge base - Google Patents

Abstract

PURPOSE:To shorten the inference time by reducing the modification of the data of a data base after storing the data in a knowledge base or the accessing amount to the data base. CONSTITUTION:A time flag for defining accessing intervals and preceding access time indicating the accessed time are provided as the fact data of a knowledge base. In addition, a means which compares the difference between the preceding accessing time and the current accessing time with the value of the time flag is provided. Then control is made so that the value of the time flag can be utilized and, in addition, the data in a fact memory can be utilized as they are in accordance with the compared result or the data newly fetched by accessing the data base.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of utilizing a database for knowledge using time flags. An expert system is a system that is realized as a knowledge base in a computer owned by an expert in a certain problem area, makes inferences, etc. based on that knowledge, and has problem-solving ability comparable to that of the expert. .

0002

2. Description of the Related Art There are mainly two types of knowledge bases in expert systems. One is the know-how of experts,
Knowledge such as rules of experience is called a rule.
The other is something that everyone recognizes, is well organized,
Systematic knowledge is said to be a fact. In fact, there are many expert systems that use database data. In order to convert the database into knowledge, the data in the database can be stored as facts in a knowledge base before inference is started, or the data in the database can be stored in the knowledge base every time the data in the database is needed during inference, as in Japanese Patent Application Laid-Open No. 1-134628. There are ways to access (acquire and modify data).

0003

[Problem to be Solved by the Invention] However, if database data is stored in a knowledge base as a fact before inference begins, it will not be possible to respond to changes in the database after storage, and each time the database data is needed, When accessing the database, there was a problem in that it took a long time to access and the speed of inference slowed down. The present invention aims to reduce the possibility of database modification after database data is stored in a knowledge base, and to shorten inference time by reducing the amount of access to the database, by using time flags. shall be.

0004

[Means for Solving the Problems] The present invention provides a time flag that defines an access interval and a previous access time that indicates the access time as part of the information expressing the facts of the knowledge base. Furthermore, means is provided for comparing the difference between the previous access time and the current access time with the value of the time flag. Then, depending on the value of the time flag and the result of the size comparison, control is performed to use the data in the actual memory as is or to use data newly fetched by accessing the database.

[0005]

[Operation] According to the present invention, for example, data once imported, such as account numbers in bank files, is used as is, and the inference time is shortened by not accessing the database. In addition, bank account balances and the like are retrieved from the database into the fact memory and used, allowing them to respond to changes in the database.

[0006]

Embodiment FIG. 1 shows an embodiment of an expert system using the present invention. In FIG. 1, 11 is a user interface section for use by a user, 12 is an inference engine that performs inference, and 13 is a knowledge base, which includes a rule memory 14 that stores rules and a fact sheet that stores facts. There is a memory 15. The database-related portion of the fact memory 15 is stored in the database access processing unit 1.
6 to access the database.

FIG. 2 is shown to explain the representation structure in fact memory. There are many ways to express facts, but here we will use a frame as an example of part of a bank's customer file. In FIG. 2, 21 indicates the name of the frame, 22 indicates the account number which is the slot name, and 23 indicates the slot value. 24 and 25 each indicate the attributes of the slot, and include an access method and a time flag. The access method 24 is written in the database, and the database access unit 16 of FIG. 1 accesses the database 17 according to the table regarding customer files and account numbers therein.

[0008] A natural number greater than or equal to 0 is entered in the time flag 25. If it is 0, it indicates that there is no change in the database; for example, the account number is 0 because it is rarely changed. Since the data does not change, there is no need to access the data once imported from the database. Therefore, if the time flag is 0, data once fetched from the database can be used as is. If the time flag is 1 or more, it indicates that the database has been changed. The value of the time flag indicates the data retention time. If the difference between the previous access time 26 and the current access time is smaller than the time flag, the data is used as is; if it is larger than the time flag, the database is deleted. Go to access. Therefore, it can be said that the smaller the time flag value is 1 or more, the more frequently the database is changed. This access time is expressed in units of seconds or internal time units of the machine on which the system is running. For example, the deposit balance in Figure 2 may change frequently,
A time flag value of 1 indicates that the database is accessed every machine internal time.

FIG. 3 is a flowchart showing the functions in FIG. In FIG. 3, when a fact is referenced in the knowledge base 13, it is determined whether the fact is from the database (step 31). If it is not a database fact, normal fact manipulation is performed (step 32). In the case of database facts, if the data is not in the knowledge base 13 (step 33), the data is read from the database 17 (step 35), the previous access time is changed to the current access time (step 36), and the data is stored in the knowledge base 13 (step 33). into the base 13 (step 37) and return the data (step 38). If the data already exists in the knowledge base 13, the difference between the previous access time and the current access time is detected and compared with the time flag (step 34), and if it is smaller than the time flag, the data is left as is. return (step 38). If it is larger than the time flag, read data from the database 17 (step 35).
), changes the previous access time to the current access time (step 36), puts the data into the knowledge base 13 (step 37), and returns the data (step 38).

0010

[Effects of the Invention] In the present invention, by using time flags, data unique to the database that does not change can be read once and the same data will be used thereafter.
Database access time can be reduced and inference time can be shortened. In addition, for data that may change in the database, the timing of accessing the database can be set by specifying a natural number of 1 or more in the time flag, reducing inference time without unnecessary access. and can respond to changes in the database.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an expert system shown to explain one embodiment of the present invention.

FIG. 2 is a diagram showing an example of fact representation shown to explain the representation structure of the fact memory in FIG. 1;

FIG. 3 is a flowchart shown to explain the functions of FIG. 1;

[Explanation of symbols]

11 User interface 12 Inference engine 13 Knowledge base 14 Rule memory 15 Fact memory 16 Database access processing unit 17
database

Claims (1)

[Claims] [Claim 1] Database knowledge in an expert system that realizes knowledge including rules and facts as a knowledge base in a computer, makes inferences based on that knowledge, and has problem-solving ability comparable to that of experts. In this method, a time flag that defines the access interval and a previous access time that indicates the access time are provided as part of the information representing each fact in the fact memory, and the previous access time and current access time are also set. and the value of the time flag, and if there is a reference to a fact in the knowledge base, and the fact belongs to a specific time flag, the fact memory is stored without accessing the database. and if the fact is of any other value of the time flag, the data in the fact memory without accessing the database, depending on the result of comparing said difference in access time with the value of the time flag in question. A method of utilizing a database for knowledge, characterized in that the method returns the data retrieved into the fact memory by accessing the database.