JPH02220136A - Inference system - Google Patents

Abstract

PURPOSE:To evade an infinite loop of inference and to improve the description property of the rule knowledge by providing a slot node and a slot deciding means and comparing a token with the slot node. CONSTITUTION:When the rule knowledges (IF A.a1=5, THEN A.a2 10) are carried out, the value '10' is set at a slot a2 of a frame A and a token related to the slot a2 is supplied to an inference network 2. Then the token is supplied to a slot node 4 related to the slot a2. Thus an intra-test is carried out in terms of the slot a2. If the token is supplied to the node 4 related to a slot a1 of the frame A, a slot deciding means 3 recognizes that the token does not belong to the slot a1. Thus no intra-test is carried out in terms of the slot a1. That is, the conditional part of this rule knowledge is not evaluated and therefore an infinite loop is evaded.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an inference method used in knowledge information processing.

[Conventional technology]

Conventionally, in this type of knowledge-based system, the management organization of rules consists of an ordered pair of tags and a list of data elements in a frame, which is a framework for expressing knowledge to be structured, and tokens, which are objects of inference. When flowing on a certain inference network, an infrastructure test is performed on one rule regarding all slots that are constituent elements of that frame and have slot values that are attribute information of that frame. In other words, decisions were not made on a slot-by-slot basis. Conventional technologies include FORGY,
C, L, RETE: Reference can be made to ``First Fist Algorithm for the Many Patterns/Many Object Patterns Matches Proprietary Artificial'' Intelligence, Volume 19, 1982.

[Problem to be solved by the invention]

In such conventional knowledge-based systems, decisions are not made on a slot-by-slot basis, so intra-tests are performed on all slots in the updated frame, which may cause an infinite loop of inference. It had the disadvantage of being high.

Here is an example that causes an infinite loop.

IF A, al=5 THEN A, a:2-
10゜In the above rule knowledge, A is a frame, al and a2 are slots of A, and it expresses "If slot a1 of frame A is 5, set 10 to slot a2 of frame A." . When this rule knowledge is executed, 10 is set in the thrower a2 of frame A. At that time, “Frame A” is displayed on the inference network.
Here, it is necessary to note that the information is not "the thrower a2 of frame A has been updated," but rather the information is "frame A has been updated." At this time, the information passes through class node A on the inference network, and all intra tests under class node A are performed.In other words, intra tests regarding all slots held by class node A are performed. A test regarding a1 will also be conducted, and the conditional part of the rule knowledge will be evaluated, and as a result, the conditional part will be satisfied, so the rule will be executed again.In this way, in the case of the rule knowledge , it will fall into an infinite loop.

[Means to solve the problem]

The method of the present invention comprises: an inference network means (hereinafter referred to as an inference network) that stores information necessary for inference; a knowledge base means (hereinafter referred to as a knowledge base) that stores knowledge including tokens; and tokens to be sent to the inference network. determining whether the token exists in the knowledge base, and setting it in the inference network as a node to which the token should flow if it exists;
An inference means for determining whether or not the set node is a slot node, and in response to the determination of the slot node by the inference means, whether or not the currently flowing token relates to the slot of the target slot node. slot determining means for determining the slot, and in response to the slot determining means determining that the token is not related to the slot, the reasoning means does not perform an infrastructure test using the token.

〔Example〕

Next, one embodiment of the present invention will be described in detail with reference to the drawings.

Referring to FIG. 1, one embodiment of the present invention includes a knowledge base 5 that stores knowledge, an inference network 2 that stores information necessary for inference, and a knowledge base 5 that stores knowledge and the inference network 2. 1, a slot node 4 for performing slot determination processing, and a slot determination means 3 for performing slot determination processing. A feature of one embodiment of the present invention is that, in FIG. 1, a slot determining means 3 and a slot node 4 are provided.

Next, the operation of one embodiment of the present invention will be described in detail with reference to FIGS. 1 and 2.

Referring to FIGS. 1 and 2, first, in step 21, the inference means 1 checks whether there is a token to be inferred that should be sent to the inference network 2. If there is no such token, the reasoner 1 performs step 21
At step 0, it is checked whether there is any rule knowledge to be executed, and if there is no rule knowledge to be executed, the process is terminated. If there is rule knowledge to be executed, the reasoning means 1 selects one rule knowledge to be executed from among the rule knowledge to be executed in step 211. Further, the inference means 1 executes the rule knowledge selected in step 212, and performs the processing from step 21 onwards.

On the other hand, if such a token exists, the reasoning means 1 retrieves the token from the knowledge base 5 in step 22. Next, the inference means 1 sets the node at the highest level of the inference network 2 as the node to which the token is to be passed in step 23 . Next, the inference means 1 checks in step 24 whether or not the node to which the token is currently flowing is the slot node 4, and if it is not the slot node 4;

The inference means 1 performs processing specific to that node in step 28, and performs processing from step 27 onwards. slot node 4
If so, the slot determining means 3 determines in step 25 whether or not the currently flowing token relates to the slot of the target slot node 4. If the token relates to the slot of the slot node 4 in question, the reasoning means 1 performs an intratest using the token in step 26;
Processing from step 27 onwards is performed. If the token is not related to the slot in question, reasoner 1
In step 27, it is checked whether the token that has just been passed needs to be passed to another node on the inference network 2, and if it is not necessary to pass the token that has just been passed, the processing from step 21 onwards is performed. If necessary, the inference means 1 sets the node to be streamed in step 29 to the node that needs to be streamed, and performs the processing from step 24 onwards.

Next, one embodiment of the present invention will be described with a specific example.

The aforementioned rule knowledge IF A, al=5 THEN A, a2←1
Think 0. This rule knowledge causes an infinite loop in conventional technology. First, when this rule knowledge is executed, the value "10" is set in the thrower a2 of frame A. Next, slot a of frame A
2 is passed to the inference network 2.

When the token is streamed to slot node 4 for slot a2 of frame A, an intratest for slot a2 is performed. However, even if the token is passed to the slot node 4 related to slot &1 of frame A, the slot determination means 3 recognizes that the token does not belong to the thrower )al, so the intratest regarding slot a1 is Not done.

In other words, the conditional part of this rule knowledge is not evaluated and its execution is not performed. In this way, the conventional technique that causes an infinite loop can be avoided by the method of this embodiment.

〔Effect of the invention〕

As explained above, the present invention is provided with a slot node and a slot judgment means, and by making a comparative judgment between a token and a slot node, an infinite loop of inference can be avoided, and the descriptive nature of rule knowledge can be improved. It has the effect of being able to

In FIG. 1, 1...inference means, 2...
... Reasoning network, 3 ... Slot judgment means, 4 ... Slot node, Death ... Knowledge base.

Claims (1)

[Scope of Claims] Inference network means for storing information necessary for inference; knowledge base means for storing knowledge including tokens; and whether or not tokens to be sent to the inference network exist in the knowledge base means. an inference means for determining whether or not the set node is a slot node, setting a node to which the token should flow when it exists in the inference network means, and determining whether or not the set node is a slot node, and responding to the determination of the slot node by the inference means; and slot determination means for determining whether or not the currently flowing token relates to the slot of the target slot node, and in response to a determination by the slot determination means that the token does not relate to the slot. and the inference means does not perform an infrastructure test using the token.