Detecting device, detecting method, and detecting program

A detection method, comprising:

• acquiring data output by sensors;
• substituting a prior distribution of an encoder in a generative model including the encoder and a decoder and representing a probability distribution of the data with a marginalized posterior distribution that marginalizes the encoder, approximating a Kullback-Leibler information quantity using a density ratio between a standard Gaussian distribution and the marginalized posterior distribution, and learning the generative model using data;
• and
• estimating a probability distribution of the data using the learned generative model and detecting an event in that an estimated occurrence probability of the data newly acquired is lower than a prescribed threshold as abnormality.

A non-transitory computer readable medium including a detection program for causing a computer to execute:

• acquiring data output by sensors;
• substituting a prior distribution of an encoder in a generative model including the encoder and a decoder and representing a probability distribution of the data with a marginalized posterior distribution that marginalizes the encoder, approximating a Kullback-Leibler information quantity using a density ratio between a standard Gaussian distribution and the marginalized posterior distribution, and learning the generative model using data;
• and
• estimating a probability distribution of the data using the learned generative model and detecting an event in that an estimated occurrence probability of the data newly acquired is lower than a prescribed threshold as abnormality.