Abstract: This signal processing device comprises: an acquisition unit for acquiring an acoustic signal; a measurement unit for measuring an acoustic level of the acoustic signal for every one of first frequency bands, which are a plurality of frequency bands of a preset first bandwidth; a calculation unit that, on the basis of the plurality of acoustic levels of the first frequency bands, identifies an acoustic feature quantity indicating the separation degree from normal acoustic levels of second frequency bands, which are a plurality of frequency bands of a second bandwidth that is wider than the first bandwidth; a first determination unit for determining whether the acoustic levels measured for every one of the first frequency bands are a first threshold value or greater; and a second determination unit for determining whether the acoustic feature quantity is a second threshold value or greater.

Abstract: Provided is a plant state monitoring method which monitors an operation state of a plant by using the Mahalanobis distance based on the plant state amount. The method creates a first unit space as a set of data used to be a reference when judging whether the plant operation state during a start operation period is normal according to the state amount in the plant start operation period. The method also creates a second unit space as a set of data used to be a reference when judging whether the plant operation state during a load operation period is normal according to the state amount in the plant load operation period.

Abstract: A water quality management device is provided with a water quality index value acquisition unit which acquires water quality index values including a makeup water quality index value indicating water quality of makeup water and a circulating water quality index value indicating water quality of circulating water, and a determining unit which determines an amount of concentration control associated with a concentration rate of a circulating water system based on the water quality index values acquired by the water quality index value acquisition unit.

Abstract: A water quality management device is provided with a water quality index value acquisition unit which acquires water quality index values including a makeup water quality index value indicating water quality of makeup water and a circulating water quality index value indicating water quality of circulating water, and a determining unit which determines an amount of concentration control associated with a concentration rate of a circulating water system based on the water quality index values acquired by the water quality index value acquisition unit.

Abstract: Provided is a plant state monitoring method which monitors an operation state of a plant by using the Mahalanobis distance based on the plant state amount. The method creates a first unit space as a set of data used to be a reference when judging whether the plant operation state during a start operation period is normal according to the state amount in the plant start operation period. The method also creates a second unit space as a set of data used to be a reference when judging whether the plant operation state during a load operation period is normal according to the state amount in the plant load operation period.

Abstract: Provided is a plant state monitoring method which monitors an operation state of a plant by using the Mahalanobis distance based on the plant state amount. The method creates a first unit space as a set of data used to be a reference when judging whether the plant operation state during a start operation period is normal according to the state amount in the plant start operation period. The method also creates a second unit space as a set of data used to be a reference when judging whether the plant operation state during a load operation period is normal according to the state amount in the plant load operation period.