@TECHREPORT{R-96-35, PSURL = {/publications/cgi-bin/tr-fetch.pl?r-96-35+ps}, NUMBER = {R-96-35}, INSTITUTION = ida, ADDRESS = idaaddr, YEAR = {1996}, AUTHOR = {Lin, Man and Malec, Jacek and Nadjm-Tehrani, Simin}, TITLE = {On Semantics of Reactive Rule-based Systems}, ABSTRACTURL = {/publications/cgi-bin/tr-fetch.pl?r-96-35+abstr}, ABSTRACT = {In this paper we address special issues which arise when the rule-based programming paradigm is emlployed in development of reactive real-time systems. We begin by presenting a rule-based language which has emerged while developing intelligent cruise control systems. We describe a naive operational semantics based on an an implemented inference engine, and explain why the semantics is not appropriate in safety-critical real-time contexts. We then define a number of correctness criteria ensuring termination, consistency and determinism, based on a formal declarative semantics. However, the declarative semantics is non-constructive. In order to be able to build an implementation satisfying the correctness criteria, two alternative approaches are proposed. Both approaches build upon static checks of a rule-based program. In the first approach some correctness criteria are met by accepting only stratified programs after the static checks. In the second approach we accept programs which are correct with respect to a constructive semantics. For both approaches we present the analysis methods and soundness results with respect to the desired declarative semantics. }