Diagnostic device, diagnostic method and program

A diagnostic method comprising:

• an acquisition step of acquiring a plurality of input signals including a target signal to be diagnosed for abnormality;
• and
• a diagnosis step of diagnosing, based on a weighted sum of a first index value and a second index value, whether an abnormality occurs, the weighted sum being calculated using weights corresponding to a correlation between the plurality of input signals, wherein
• the first index value indicates (i) a degree of similarity of a waveform of the target signal to a predetermined reference waveform or (ii) a degree of deviation of the waveform of the target signal from the predetermined reference waveform,
• the second index value is a value that is based on comparison between the target signal and a predetermined pattern and is calculated using values of the plurality of input signals, and
• a weighting coefficient of the first index value that is used to calculate the weighted sum when a degree of correlation between the plurality of input signals is high is smaller than a weighting coefficient that is used to calculate the weighted sum when the degree of correlation between the plurality of input signals is low.

A non-transitory recording medium storing a program causing a computer to implement:

• acquiring a plurality of input signals including a target signal to be diagnosed for abnormality;
• and
• diagnosing, based on a weighted sum of a first index value and a second index value, whether an abnormality occurs, the weighted sum being calculated using weights corresponding to a correlation between the plurality of input signals, wherein
• the first index value indicates (i) a degree of similarity of a waveform of the target signal to a predetermined reference waveform or (ii) a degree of deviation of the waveform of the target signal from the predetermined reference waveform,
• the second index value is a value that is based on comparison between the target signal and a predetermined pattern and is calculated using values of the plurality of input signals, and
• a weighting coefficient of the first index value that is used to calculate the weighted sum when a degree of correlation between the plurality of input signals is high is smaller than a weighting coefficient that is used to calculate the weighted sum when the degree of correlation between the plurality of input signals is low.