“…Our view of control is motivated by the following observations, which are based on analyses of the control strategies of CASNET [Weiss et al, 1977], [Weiss et al, 1978], PIP [Pauker et al, 1976], HEARSAY-II [Erman and Lesser, 1975], [Erman et al, 1980], MUM [Cohen et al, 1987a], MDX [Chandrasekaran et al, 1982], [Chandrasekaran and Mittal, 1983], NEOMYCIN [Clancey, 1986], [Clancey,], DOMINIC and DOMINIc-If [Howe et al, 1986], [Orelup et al, 1988]: 59 Observation-1: The control strategies of many knowledge systems can be viewed as the interaction of a small number of simpler strategies. We call these strategy frames.…”