Patent ID: 7483934

Claim:
A method for detecting an error operation of physical sensors in a system, the method comprising: defining a first similarity matrix for a target run of data, wherein the target run of data includes data obtained from an N number of physical sensors in the system; defining a second similarity matrix for a reference run of data, wherein the reference run of data includes data obtained from the N number of physical sensors in the system; developing a k-neighborhood graph N i of the i-th node for the target run of data, wherein the k-neighborhood graph of the i-th node is defined as a graph comprising the i-th node and its k-nearest neighbors (NN); developing a k-neighborhood graph N i of the i-th node for the reference run of data; defining a probability distribution p(j/i), wherein p(j/i) is the probability that the j-th node becomes one of the k-NN of the i-th node; summing the probabilities between the i-th node and the neighbors of the i-th node; determining an anomaly score of the i-th node from the sum of the probabilities; wherein the anomaly score is defined as max{|e i (N i )|,|e i ( N i )−ē i ( N i )|}, wherein e i (N i ) is the sum of the probabilities of the target data as a function of the target data, ē i (N i ) is the sum of the probabilities of the reference data as a function of the target data, e i ( N i ) is the sum of the probabilities of the target data as a function of the reference data, and ē i ( N i ) is the sum of the probabilities of the reference data as a function of the reference data; determining whether the target run of data has changed from the reference run of data responsive to determining the anomaly score of the i-th node; comparing the anomaly score of the i-th node with a threshold value to determine whether the anomaly score of the i-th node exceeds the threshold value responsive to determining that the target run of data has changed from the reference run of data; and outputting the anomaly score responsive to determining that the anomaly score of the i-th node exceeds the threshold value, wherein the output anomaly score is indicative of the error operation in the physical sensors of the system.