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Development of Knowledge Representation Language Based on the Inheritance Hierarchy Prolog

基于继承层次结构的知识表示语言Prolog的开发

基本信息

批准号：
63880005
负责人：
AKAMA Kiyoshi
金额：
$ 2.05万
依托单位：
Hokkaido University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research (B).
财政年份：
1988
资助国家：
日本
起止时间：
1988 至 1989
项目状态：
已结题

项目摘要

In this research we have constructed a knowledge representation system PAL89 which is an extention of pa186, that is, an extended prolog to deal with inheritance hierarchy which is a tree structure formed by the inclusion relation among classes and instances. Pa186 adopts class bound variables (CBVs), which are variables with class constraints. CBVs improve the inferential efficiency greatly by suppressing unnecessary backtracking and exhaustive searches.The characteristics of PAL89 include1. Extended functions of CBVs. (1) Variables can have any constraints which are computed by set operations (difference, union and intersection), which enables the system to provide declarative multiple inheritance representation. (2) A inheritance hierarchy compiler and inheritance hierarchy clause indexing are implemented, which makes the system faster.2. Typed cons patterns. AII objects used in PAL89 can have types. So PAL89 can be regarded as a typed prolog. Types play an important role in partial evaluation, learning and automatic program generation.3. Variables with constraints. Users can introduce new classes of variables with constraints and their unification. Therefore the user can define new objects by variables with constraints and can represent relations between them. This leads us to the concept of "DUAL PROGRAMMING", that is, two step Programming whose first step is defining objects and second step is defining relations.

本研究构造了一个知识表示系统PAL 89，它是PA 186的扩展，即一个扩展的Prolog，用来处理继承层次，继承层次是由类和实例之间的包含关系形成的树结构。Pa186采用类绑定变量（CBV），即具有类约束的变量。CBVs通过抑制不必要的回溯和穷举搜索，大大提高了推理效率。CBV的扩展功能。(1)变量可以有任何由集合运算（差分、联合和交集）计算的约束，这使得系统能够提供声明性的多重继承表示。(2)实现了继承层次编译器和继承层次子句索引，提高了系统的运行速度.类型化的骗局模式。PAL 89中使用的所有对象都可以有类型。所以PAL89可以看作是一个类型化的prolog。类型在部分求值、学习和程序自动生成中起着重要作用.带约束的变量用户可以引入新的变量类的约束和他们的统一。因此，用户可以通过带有约束的变量定义新的对象，并可以表示它们之间的关系。这就引出了“双重编程”的概念，即两步编程，第一步是定义对象，第二步是定义关系。