Abstract: A corrosion rate estimation apparatus includes a corrosion rate measurement unit adapted to repeat water supply cycles in which water is supplied to soil in which metal to be evaluated is buried and measure a cycle number of each water supply cycle, one or more time points in each cycle, and a corrosion rate of the metal at the time point(s); a learning unit adapted to find a prediction model by accepting the cycle number, the time point(s) in the cycle, and the corrosion rate(s) as input and using a machine learning algorithm, the prediction model representing a future corrosion rate; and a corrosion rate estimation unit adapted to assign a cycle number and a time point in the cycle at which a corrosion rate is desired to be estimated to the prediction model and estimate a corrosion rate of the metal at the time point.

Abstract: A corrosion amount estimation apparatus includes a soil analysis unit adapted to acquire a particle diameter distribution in soil in each of plural soil samples; a corrosion measurement unit adapted to take electrochemical measurements at plural soil moisture percentage values on an electrode containing the metallic material buried in each of the soil samples; a soil classification unit adapted to classify the soil in each of the soil samples; a corrosion rate calculation unit adapted to calculate a corrosion rate regarding each of the soil samples at each of the soil moisture percentage values and identify a local maximum corrosion rate; a corrosion estimation curve generation unit adapted to generate a corrosion estimation curve; and a corrosion amount estimation unit adapted to acquire the class proportions of actual soil in which the metallic material is buried, acquire the local maximum corrosion rate corresponding to the class proportions from the corrosion estimation curve, and estimate the corrosion a

Abstract: An uninterrupted power supply apparatus includes input lines configured to receive AC power from an AC power supply having a grounded neutral point, a converter configured to convert the AC power of the input lines to DC power for output to intermediate lines, a power storage unit connected to the intermediate lines, an inverter configured to convert DC power of the intermediate lines into AC power for output to output lines, grounding capacitors connected between the input lines and a ground, a phase voltage detecting unit configured to detect phase voltages between the input lines and the ground, and a control unit configured to monitor fluctuations of the phase voltages detected by the phase voltage detecting unit to detect a failure that causes abnormal voltage to the input lines.

Abstract: In an uninterruptible power supply, a signal generator generates a semiconductor switch drive signal for driving a semiconductor switch and continuously generates the semiconductor switch drive signal while AC power is being supplied via a bypass circuit.