A Parallel Backward‐chaining Strategy Based on the Concept of OR‐Node Levels in the AND/OR Tree

Applies a parallel backward‐chaining technique to a rule‐based expert system on a shared‐memory multiprocessor system. The condition for a processor to split up its search tree (task‐node) and generate new OR nodes is based on the level in the goal tree at which the task‐node is found. The results indicate satisfactory speed‐up performance for a small number of processors (< 10) and a reasonably large number of rules.