A REDUCED INSTRUCTION SET MACHINE FOR KNOWLEDGE BASED SYSTEMS

Abstract

This work proposes a system level design of a special purpose RISC architecture for the implementation of Knowledge Based Systems (KBS). The processor implements an Instruction Set Architecture (ISA) derived from the description of the Rete algorithm given in Forgy (1982) - the paper that proposes the algorithm - alongside some general purpose instructions (not described here). It is part of a System-on-a-Chip (SoC) for the  execution of cognitive agents. The computational architecture of this SoC will be presented using the cognitive model of the Concurrent Autonomous Agent (CAA) as a reference, since it has been successfully applied in numerous intelligent robotics applications. The cognitive model of the CAA comprises three levels that run concurrently: the reactive level, which executes the perception-action cycle, the instinctive level, that manages plan execution, and the cognitive level, which performs planning. In the method here proposed, the KBS knowledge base is compiled into a program composed by the application specic instructions and the matching procedure is executed by the processor using this program. To validate the architecture of this processor, some experiments using an example knowledge base will then be presented. The experiments - performed using a system-level simulator written in the Scala language - shown that the simulated architecture reported the expected matches for additions and exclusions of facts from the Rete memories.