Abstract: A method and system for diagnosing the behavior of a machine which performs a discrete event process. A diagnostic engine observes occurrences of discrete events to detect timing patterns. A statistical analysis is performed on repetitions of the timing patterns, thus providing the basis for defining diagnostic rules. The rules are updated in real time and are subject to a rule competition procedure in which only the most precise and efficient rules are selected. Further occurrences of discrete events are evaluated relative to the diagnostic rules to identify and predict malfunctions of the machine.

Abstract: Disclosed is a method for determining the dispersion of a surface acoustic wave in an object, including the steps of generating a broadband acoustic wave in a surface of the object, detecting the wave at first location on the surface, and detecting the wave at a second location on the surface. Fourier transforms of the first and second detected waves are calculated, then the change in phase .DELTA..phi.(f) of the frequency component f of the detected wave, between the first and second locations, is computed from the phase components of the quotient of the two transforms. The dispersion of the wave in the surface is given by the formulav(f)=(2.pi.f .DELTA.l/.DELTA..phi.(f))In a pulse-echo version of the method, the wave is generated and detected at the first location, and generated and detected at the second location, the dispersion then being according to the formulav(f)=4.pi.f .DELTA.l/.DELTA..phi.(f)).

Abstract: Ultrasonic inspection of a structure such as steel tubing is enhanced by moving the ultrasonic wave transmitter and receiver through the pipe and periodically injecting an ultrasonic pulse into the tube. Reflected waves are received during a sample period after each pulse injection. By proper selection of linear displacement between pulses and the sample time interval, the time reference of received signals can be adjusted whereby signals reflected from only one direction are coherently added.