JP2785302B2 - Expert system knowledge base management system. - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Industrial Field of the Invention The present invention relates to an inference data management device in a knowledge base system.

B. Summary of the Invention A time variable frame that manages a buffer and temporarily stores a value is provided in the frame slot type in the knowledge base,
In addition, the buffer is formed in a ring structure and the past data is stored for a certain period of time so that data that changes with time can be handled sufficiently efficiently.

C. Prior Art Expert systems are being popularized, in which a computer is made to have the ability of an expert by using the empirical knowledge of an expert in a specific field. FIG. 3 shows an inference unit in the expert system, wherein 1 is an inference engine, 2 is a knowledge base, and is composed of a rule set and a fact set. The rule set is if A
Knowledge is represented by the production rules of then B, and the fact set is described by frame representation. in this case,
A certain fact is defined by a set of pairs of a slot name, a slot type, and a slot value constituting a frame. Reference numeral 3 denotes an execution unit that executes the matching rules based on the knowledge base and outputs the result.

D. Problems to be Solved by the Invention When new data is substituted for a slot value in a frame, the previously recorded slot value is discarded and new data is rewritten as a slot value. As an application field of the expert system, for example, when considering a supervisory control device, the retention of time-series data and the operation occupy an important position in the knowledge expression handled in this field. There was no way to handle data that changes with time naturally enough efficiently.

Accordingly, it is an object of the present invention to provide an inference data management device capable of retaining data before a certain period of time while maintaining consistency with a conventional frame system.

E. Means for Solving the Problems In the present invention, an inference engine performs inference with reference to a knowledge base, and has a time variable management mechanism unit that is activated at predetermined time intervals. Further, a time variable frame for managing a time variable in a slot of the frame of the knowledge base is provided, and the time variable frame has a circular structure,
The management mechanism comprises a buffer for writing a value and a time.

F. Action The time variable management mechanism is activated at regular intervals and transfers the values and attributes in the current value slot of the frame of the time variable to a predetermined position in the buffer with reference to the buffer management information. At this time, the management mechanism unit advances the current value stored in the buffer unit by one and stores the new data, and also writes the time at that time.

G. Embodiment FIG. 1 is a block diagram showing an embodiment of the present invention, wherein 1 is an inference engine, 3 is a conforming rule execution unit, 20 is a knowledge base,
This knowledge base 20 has a rule set part expressed in knowledge by the production rule of if A then B and a fact set part described in frame expression. Reference numeral 5 denotes an example of a frame of the fact collection part. In the present invention, a time variable is provided in the slot type of this frame. Reference numeral 51 denotes a time variable frame in which a value or the like is written in a slot value of the frame. A buffer management information unit 510 for managing a buffer unit, which will be described later, and a part 511 in which a current value and attributes such as certainty factor and a time tag are stored. And It should be noted that the management information section 510 holds the cycle at which the management mechanism section is started, the size of the buffer section, the current position of data stored in the buffer section, and the like. Reference numeral 4 denotes a management mechanism unit, which is started at regular time intervals to manage time variables. Reference numeral 6 denotes a buffer unit, which has an annular structure in which values, times, and the like are written, and in which n values and the like are written.

The operation of the present invention configured as described above will be described.

The inference engine 1 makes an inference while referring to the knowledge in the knowledge base 20, and the execution unit 3 executes the matching rule and outputs the result. When such an expert system is executing process control, the inference engine 1 converts the detected process value into a predetermined frame 5 of the knowledge base 20.
Assign a value to the slot of.

Now, when the slot type is a time variable, for example, a water level at a certain time, the detected current value is the slot value 51
Current value storage part 511 of the time variable frame referred to by
Is stored in

On the other hand, the management mechanism unit 4 for managing the time variable is started at a certain time T, and at the time of the start, the current value frame is referred to while referring to the information stored in advance in the buffer management information unit 510 of the variable frame. The values and attributes written in 511 are the values 1 and 2 where the latest information of the buffer unit 6 is written.
At the same time as the transfer to the attribute 1 position, the time at that time is written to the time 1 position. At the next time when the management mechanism 4 is activated, the current value, which is the latest information, is written to each of the 2 (not shown) areas of the buffer unit 6, and in the same manner, sequentially from k to n. . When the current position reaches the tail area n, the next position is written to the top area 1 and the old data written to the area 1 is inevitably erased. The positions of these current values are stored in the buffer management information section of the time variable frame each time, and are sequentially advanced by the management mechanism section 4 which refers to this.

Next, a method of calling the value of the designated time using the time series data written in the buffer unit 6 will be described with reference to FIG.

The data value stored in the buffer unit 6 is at time t _n-1
The time of a a _n-1 values, the time t _n in a _n, the time t _{n + 1} in a _{n + 1} ...... discretely collected data with respect to time as it is recorded. Of such data, data that users need, not matching the recorded discrete time, for example, t _n and t _{n + 1} intermediate point is (for example, 10 minutes before the current) t _n 'Data may be required. In this case, the management mechanism unit 4 calculates the neighborhood value of the desired time.
a _n, interpolated reference to a _{n + 1,} to calculate the value a _n at time t _n 'point. In other words, referring to the past discrete data stored in the knowledge base, the knowledge display "measured value 10 minutes before the present,
If more than a certain value ", the rule can be realized.

H. Effects of the Invention According to the present invention as described above, the following effects can be obtained.

(1) While maintaining consistency with the conventional frame system,
The function of the time variable can be easily added.

(2) Time-varying data can be efficiently stored in the knowledge base, and the rule of “if the measured value 10 minutes ago is greater than or equal to a certain value” in the knowledge expression with reference to the stored past data Can be realized.

(3) By adopting the buffer structure, it is possible to obtain an optimum structure for the purpose of use by setting the size and the transfer cycle.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is stored time-series data, and FIG. 3 is a schematic diagram of a conventional expert system. 1 ... inference engine, 4 ... management unit, 5 ... frame, 51 ... time variable frame, 6 ... buffer unit, 20 ...
… Knowledge base.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G06F 9/44

Claims (1)

(57) [Claims] 1. An expert system having a knowledge base expressed as a frame as a knowledge expression and an inference engine for executing inference while securing an area, rules, and the like of the knowledge base, wherein a frame having a slot-type time variable is provided. In order to manage this time variable, the start cycle, the size of the buffer, the buffer management information slot in which the buffer management information holding the current position of the buffer is written, the current process value, and the attribute are stored by the inference engine. A time variable frame having a current value slot to be written; a buffer in which data values, attributes, and times of processes that are formed in a circular fashion and collected discretely are respectively written in predetermined positions as past data; It is provided for the management of A time variable management mechanism for sequentially writing past data in the buffer while referring to buffer management information, and interpolating the discrete-time data value based on a value near a desired time when the time does not match a user request time. An expert system knowledge base management device characterized by the following.