if then

mostly clear toward midnight becoming cooler overnight low 35 to 40 degrees winds becoming westerly light to moderate snow occasional rain widely scattered showers increasing high cloudiness

-

Mostly clear toward midnight becoming cooler overnight low 35 to 40 degrees winds becoming westerly light to moderate snow occasional rain widely scattered showers increasing high cloudiness

no change some change nothing

dry period dry period ending wet wet period ending stormy period stormy period ending nothing

or (If-earlier-wind-direction east) (if-earlier-wind-direction southeast) (if-earlier-wind-direction south)) (if-current-wind-direction west) THEN (assert (immediate-general-trend (forecast change-in-weather)) (immediate-detailed (forecast dry-period)))

S SW

or (If-current-wind-direction south) (If-current-wind-direction southwest) (current-barometric-pressure ?press) (test (<= 30.00 ?press)) (If-barometric-pressure-trend rising-slowly) THEN (END (immediate-general-trend (forecast change-in-weather)) (immediate-detailed (forecast wet-period-ending)) (immediate-detailed (forecast dry-period)) (future-detailed (forecast dry-period))

DFD

WXSYS

Weather Lore + Fuzzy Logic = Weather Forecasts

© 1997 by Walter Maner and Sean Joyce

Presented at the 1997 CLIPS Virtual Conference

Distributed with Girratano and Riley, Expert Systems Principles and Programming, 3rd edition