Amk. Cheng et al., ANALYSIS OF REAL-TIME RULE-BASED SYSTEMS WITH BEHAVIORAL CONSTRAINT ASSERTIONS SPECIFIED IN ESTELLA, IEEE transactions on software engineering, 19(9), 1993, pp. 863-885
Rule-based expert systems are increasingly used to monitor and control
the operations of complex real-time systems which require intensive k
nowledge-decision processing and human expertise. These embedded AI sy
stems must respond to events in the rapidly changing external environm
ent so that the results of the expert system's computation in each mon
itor-respond cycle are valid in safely operating the real-time system.
Determining how fast an expert system can respond under all possible
situations is a difficult problem. We have developed an efficient anal
ysis methodology for a large class of rule-based EQL programs to deter
mine whether a program in this class has bounded response time. In par
ticular, we have identified several sets of primitive behavioral const
raint assertions: an EQL program which satisfies all constraints in on
e of these sets of assertions is guaranteed to have bounded response t
ime. Here, we enhance the applicability of our analysis technique by i
ntroducing a facility with which the rule-based programmer can specify
application-specific knowledge that is too difficult to be mechanical
ly detected in the new language Estella in order to determine the perf
ormance of an even wider range of programs. We also describe efficient
algorithms for implementing the analysis tools.