Howard E. Shrobe

AAAI Conference 1993 Conference Paper

Supporting and Optimizing Full Unification in a Forward Chaining Rule System

• Howard E. Shrobe

The Rete and Treat algorithms are considered the most efficient implementation techniques for Forward Chaining rule systems. These algorithms support a language of limited expressive power. Assertions are not allowed to contain variables, making universal quantification impossible to express except as a rule. In this paper we show how to support full unification in these algorithms. We also show that: Supporting full unification is costly; Full unification is not used frequently; A combination of compile time and run time checks can determine when full unification is not needed. We present data to show that the cost of supporting full unification can be reduced in proportion to the degree that it isn’ t employed and that for many practical systems this cost is negligible.

AAAI Conference 1993 Conference Paper

Understanding Linkages

• Howard E. Shrobe

AAAI Conference 1988 Conference Paper

Towards a Virtual Parallel Inference Engine

• Howard E. Shrobe

Parallel processing systems offer a major improvement in capabilities to AI programmers. However, at the moment, all such systems require the programmer to manage the control of parallelism explicitly, leading to an unfortunate intermixing of knowledge-level and control-level information. Furthermore, parallel processing systems differ radically, making a control regime that is effective in one environment less so in another. We present a means for overcoming these problems within a unifying framework in which 1) Knowledge level information can be expressed effectively 2) Information regarding the control of parallelism can be factored out and 3) Different regimes of parallelism can be efficiently supported without modification of the knowledge-level information. The Protocol of Inference introduced in [Rowley et al. , 19871 forms the basis for our approach.