Fecha de publicación: 29/12/2022 Fuente: WIPO (eseential oils OR extracts) A learning device includes: a data acquisition unit that acquires time-series data of a normal time; a time frequency analysis unit that analyzes a chronical change of a frequency feature to the time-series data of the normal time acquired by the data acquisition unit; a feature difference emphasis range extraction unit that extracts, from the data that has been analyzed by the time frequency analysis unit, a signal intensity data in a range of a specified frequency band and a specified time period where a feature difference between the normal time and an abnormal time increases; and a model generation unit that uses the signal intensity data extracted by the feature difference emphasis range extraction unit in the range of the specified frequency band and the specified time period to generate a learned model for inferring similarity with the data of the normal time.