A Semantics for a Stratified Production System Program

这个项目研究了一些技术，这些技术允许用生产系统（PS）范式编写的程序正确有效地对位于二级存储上的大型数据库进行推理。确定了一类分层的PS程序。对于这类程序，开发了操作语义和模型理论语义。正确的语义确保分层PS程序将对应于一致的理论，程序的执行将不会产生不正确的，不一致的答案，程序的执行将终止。开发了使用关系数据结构和关系查询的分层PS程序的实现技术，以及分层PS程序中并发执行产品的策略。本研究的结果将为专家系统提供基础，将其编写为分层PS程序，以正确有效地对关系数据库中的数据进行推理。

This project investigates techniques that allow programs written in the Production System (PS) paradigm to reason correctly and efficiently with large databases located on secondary storage. A class of stratified PS programs are identified. For this class of programs, an operational semantics and a model theoretic semantics are developed. The correct semantics ensure that a stratified PS program will correspond to a consistent theory, the execution of the program will not produce incorrect, inconsistent answers and execution of the program will terminate. Implementation techniques for stratified PS programs using relational data structures and relational queries are developed as well as strategies for the concurrent execution of productions in stratified PS programs. The results of this research will provide a foundation for expert systems, written as stratified PS programs, to reason correctly and efficiently with data in relational databases.