Monitoring device, method for monitoring target device, and program

A method for monitoring a target device, comprising:

• acquiring, by a monitoring device, measurement values of the target device, the measurement values including at least a temperature and a flow rate of an input fluid to be input to the target device, and a temperature and a flow rate of an output fluid to be output from the target device;
• obtaining, by a monitoring device, correction measurement values in which the measurement values are corrected by using thermal equilibrium calculations based on the measurement values;
• calculating, by a monitoring device, a Mahalanobis distance with a factor of the correction measurement values;
• when the calculated Mahalanobis distance is equal to or larger than a predetermined value, calculating, by a monitoring device, an SN ratio related to the Mahalanobis distance and obtaining, by the monitoring device, likelihoods by calculating a likelihood associated with an occurrence of each of M kinds of phenomena that are liable to occur to the target device based on the SN ratio for each of the phenomena;
• estimating, by the monitoring device, occurrence causes of abnormalities based on a vector including N elements that is obtained by calculation using a vector including the likelihoods as elements and a matrix including values of a table as elements in which each of the M kinds of phenomena and the occurrence causes of N kinds of abnormalities of the target device are associated with one another, wherein a number of the likelihoods is M that is same as a number of the kinds of phenomena;
• and
• outputting the estimated occurrence causes of the abnormalities of the target device to a display screen or printing the estimated occurrence causes of the abnormalities of the target device on a sheet.

A non-transitory computer-readable medium having a program stored thereon, the program causing a computer to execute the following processing:

• acquiring measurement values of the target device, the measurement values including at least a temperature and a flow rate of an input fluid to be input to the target device, and a temperature and a flow rate of an output fluid to be output from the target device;
• obtaining correction measurement values in which the measurement values are corrected by using thermal equilibrium calculations based on the measurement values;
• calculating a Mahalanobis distance with a factor of the correction measurement values;
• when the calculated Mahalanobis distance is equal to or larger than a predetermined value, calculating an SN ratio related to the Mahalanobis distance and obtaining likelihoods by calculating a likelihood associated with an occurrence of each of M kinds of phenomena that are liable to occur to the target device based on the SN ratio for each of the phenomena;
• estimating occurrence causes of abnormalities based on a vector including N elements that is obtained by calculation using a vector including the likelihoods as elements and a matrix including values of the table as elements in which each of the M kinds of phenomena and the occurrence causes of N kinds of abnormalities of the target device are associated with one another, wherein a number of the likelihoods is M that is same as a number of kinds of phenomena;
• and
• outputting the estimated occurrence causes of the abnormalities of the target device to a display screen or printing the estimated occurrence causes of the abnormalities of the target device on a sheet.