Patent ID: 6421632
Filing Date: 2002-07-16
Classification: G06F,H04L,H04M

Abstract:
A method for performing, in a computer-controlled process, an algorithm-controlled monitoring of disturbances which may occur at random or in bursts in the process, said monitoring using counting values obtained from a counter for counting said disturbances, said method comprising:i) defining an abnormal event regarded to be a disturbance, ii) defining a base against which disturbances are to be counted, comprising determining whether the base should be a unit of time, a base event, or an artificial base, the outcome being a random variable able to take a value indicating normal event or disturbance, iii) defining a unit to be used as a measure of a disturbance frequency, iv) determining values of the disturbance frequency in circumstances that can be expected in operation of a process generating the disturbance to be monitored, said values including a critical value fC of the disturbance frequency where the monitoring nominally issues an alarm, v) determining for the process, at said critical value, a peakedness factor F, being a measure of how bursty the disturbances are, as the ratio of the variance to the mean of occurrences of disturbances in the process, vi) choosing for the algorithm an inertia value J being a measure of how fast or slowly the algorithm is desired to react to changes in the disturbance frequency, so as to achieve an acceptable compromise between speed and reliability of the monitoring, vii) calculating parameters for the monitoring based upon the disturbance frequency value fC, the peakedness factor F and the inertia value J, and using said parameters to calculate according to 1/fC*J*F a threshold value T of the counter considered to be unacceptable, iix) designing the algorithm for the monitoring with said parameters, ix) initiating the monitoring and waiting for results thereof, x) evaluating the results and, if necessary, adjusting the parameters.