Fecha de publicación: 04/01/2023 Fuente: WIPO (eseential oils OR extracts) A waveform of each predetermined series of vibrations included in a vibration waveform is referred to below as an "individual waveform (Wo)". An end determination unit (34) determines an end of each individual waveform (Wo), and thus recognizes a boundary between individual waveforms (Wo). A feature extraction unit (33) extracts features (Ps, Pm, Pe) of each individual waveform (Wo) on the basis of the recognized boundary. A knocking determination unit (35) determines, with respect to each individual waveform (Wo) of which the features have been extracted by the feature extraction unit (33), whether the features are features of a knocking waveform. The knocking determination unit (35) then determines that knocking is present on the condition that the features of one of the individual waveforms (Wo) are determined to be the features of the knocking waveform.