JPH0535482A - Object oriented database for expert system - Google Patents

Abstract

PURPOSE:To easily protect data without fail by adding protection information to a slot, referring to the slot within a succession range and deciding the propriety of the change. CONSTITUTION:Frames C11, I11, and I12 to be a class or an instance of a knowledge base 1A is set up in a hierarchical structure with respective levels. In slots SA to SE, values decided by each level is described by a succession mechanism. In this case, protection information A and B is provided beside the value in the slots SA to SE. This protection information A and B is succeeded by having a succession mechanism like the succession of the slots SA to SE, setting whether the slots SA to SE can be referred to or changed. In short, in the case of updating data, the protection information A and B checks the succession of the data within the range to be succeeded, and prevents the interference from another inference process by adding inhibiting information.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to object-oriented databases in expert systems.

[0002]

2. Description of the Related Art The expert system is basically constructed as shown in FIG. The knowledge of experts in each field is stored in the knowledge base 1, and the inference mechanism 2 obtains an answer to the question from the user by inference using the knowledge of the knowledge base 1.

The inference mechanism 2 performs inference by securing data such as knowledge base areas, rules and facts necessary for the inference work process in the working memory 3. Further, the man-machine interface 4 with the user is provided with an editor function, a debugger function, etc. for accepting questions having an explanation function for inputting / outputting information and inputting / outputting the knowledge base 1.

Known knowledge representations of the knowledge base 1 are a production rule representation in the form of IF <condition part> THEN <execution part>, and a frame representation in which abstract concepts and entities are represented as frames in a hierarchical network. Furthermore, there is also a combination of both.

The knowledge base based on the frame representation has recently been made into an object-oriented data structure, and the data structure and the operations that can be used on it are collectively defined as a data type (frame), and each object is defined by its data type. being classified.

[0006] FIG. 3 shows a database structure for each company. Class definitions are made from the highest class that expresses the abstract concept of a company to the lowest class that expresses industries such as automobiles and electric appliances. Are defined as instances of concrete objects or concepts such as company A and company B, respectively.

Each frame is a method (procedural knowledge)
A set of operations that can be applied to objects of that class called is prepared, and a method inheritance mechanism that allows a method defined in a higher class to be used in a lower class is provided and the method definition is simplified.

For example, if a company class has a slot, the slot value is inherited by classes and instances below the company class. When the company has a slot with the name "purpose", the slot "purpose" is inherited in the hierarchy below the company class, and at the same time, the value is inherited.

[0009]

In the conventional object-oriented database, the data (value) is inherited by the inheritance mechanism, and classes and instances are created and deleted.

This means that the database is valid only for a single inference process, and it is difficult to refer to the same database from multiple inference processes.

For example, if one inference process refers to another process while updating a value, the data may be destroyed. In the case of a class slot, the location where data is stored corresponds to the defined class, but since it can be referenced and updated by instances and classes under that hierarchy, the data is destroyed by the reference and update by multiple processes. .

A protection method may be considered in which the entire database is locked at the time of updating the data, but during that time, reference and change from other inference processes become impossible and the processing efficiency is deteriorated.

It is an object of the present invention to provide an object-oriented database that ensures and facilitates data protection while allowing reference and modification from multiple inference processes.

[0014]

In order to solve the above-mentioned problems, the present invention provides an expert system object-oriented database having a method-inheriting mechanism and a hierarchical frame structure as a knowledge base. The slot is characterized by having protection information for determining whether or not the slot can be referenced or changed by the inference process within the range where the value is inherited.

[0015]

[Operation] When the protection information is added to the slot of each frame and the slot value is changed by the inference process, the protection information is referred to as the prohibition information of the slot within the inheritance range of the slot, and the reference and the change from other inference processes are made. It is prohibited only within the inheritance range. When the change of the slot value is completed, the prohibition information of the inheritance range is released.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a database configuration diagram showing an embodiment of the present invention. Frames C11, I11, I12, which are classes or instances of the knowledge base 1A, have a hierarchical structure having respective levels, and slots SA to SE are described with values determined by the respective levels having an inheritance mechanism.

Here, the slot is provided with protection information A and B in addition to its value. This protection information is inherited with an inheritance mechanism similar to the inheritance of slots, and sets whether or not the slot can be currently referenced or updated. That is, the protection information checks the inheritance of the range in which the data is inherited when updating certain data, and adds prohibition information to prevent interference from other inference processes. This prohibition information is released following the same inheritance when the update is completed.

For example, when updating the value of the slot SA of the class frame C11 by the inference process 2A, the instance frames I11 and I12 are traced and prohibition information is added to the corresponding slots, respectively. During this update, another inference process 2B is executed. References and updates by are prohibited.

Here, since the protected data area is limited to the range which is inherited by tracing the hierarchy of the frame structure,
The protected data area to which prohibited information is applied is minimized,
The protection information can be easily processed, competition with other inference processes can be minimized, and addition of the protection information hardly reduces the access speed of each inference process.

[0020]

As described above, according to the present invention, since the protection information is added to the slot and the protection information determines whether to refer to or change the slot within the inheritance range, other data is updated when the frame data is updated. The reference from the inference process is prohibited to ensure the data protection, and the reference is prohibited within the inheritance range to simplify the processing of the protection information, and the reference by other inference process can be performed outside the inheritance range.

[Brief description of drawings]

FIG. 1 is a database configuration diagram of an embodiment.

FIG. 2 is a basic configuration diagram of an expert system.

FIG. 3 is a frame configuration diagram of an object-oriented database.

[Explanation of symbols]

1 ... Knowledge base, 2 ... Inference mechanism, 3 ... Working memory, 4 ... Man-machine interface, 1A ... Knowledge base, 2A, 2B ... Inference process.

Claims (1)

Claim: What is claimed is: 1. In an object-oriented database of an expert system having a method inheritance mechanism and having a hierarchical frame structure as a knowledge base, a range in which the value is inherited to the slot of each frame. An object-oriented database of an expert system, which has protection information for determining whether or not it can be referenced or changed by an inference process in the database.