受験番号：24IPE014問１）
1. An alternate current arc welding device comprising:a welding controller;a storage unit;
an alternate current frequency setting unit configured to set an alternate
current frequency;
a reverse polarity period setting unit configured to set a reverse polarity period;a calculating unit configured to calculate a straight polarity period and areverse polarity period and output the straight polarity period and the reverse polarity
period to the welding controller; anda selection unit configured to select one of a plurality of outputs from thestorage unit and output the selected output to the calculating unit, wherein
the welding controller is configured to apply a straight polarity base current
that is lower than a peak current of the straight polarity period before polarity
reversion at which the straight polarity period is completed, and apply a reverse
polarity base current that is lower than a peak current of the reverse polarity period
before polarity reversion at which the reverse polarity period is completed,the storage unit is configured to:(a) store a plurality of combinations of a straight polarity base ratio and areverse polarity base ratio, the straight polarity base ratio being a ratio of a period
when the straight polarity base current is applied to the straight polarity period, thereverse polarity base ratio being a ratio of a period when the reverse polarity basecurrent is applied to the reverse polarity period, or(b) store a plurality of combinations of a straight polarity peak period, astraight polarity base period, a reverse polarity peak period, and a reverse polarity baseperiod, the straight polarity peak period being a period when the peak current in thestraight polarity period is applied, the straight polarity base period being a period when
the straight polarity base current is applied, the reverse polarity peak period being aperiod when the peak current in the reverse polarity period is applied, the reverse
polarity base period being a period when the reverse polarity base current is applied,andthe selection unit is configured to select one of the plurality of combinations
stored in the storage unit based on an inductance of a welding load.

問 2)
In a conventional monitoring system with a sensor installed at, for example, agate of a parking lot, the system can detect a motor vehicle at the gate, allow a mobilerobot to get to the gate where the sensor is installed, process images taken on the way to
the gate, determine the body color of the motor vehicle, and send the information to acenter. In this case, the monitoring system preferably takes the images in such a way
as to obtain information useful to identify motor vehicles.
The parking manner of a motor vehicle, however, depends on, for example, thenature of a thief and the circumstances of a parking lot and thus cannot be anticipated.
It may therefore be difficult for the mobile robot to take images of a motor vehicle toidentify the body color of a motor vehicle.
For example, when the system is to take images of a motor vehicle with a color
visible light camera to determine a body color, the color may be different between
images taken in the daytime and image taken in the evening due to influences ofsunlight. A white motor vehicle thus may be determined to be orange when taken in
the evening. Further, unfortunately, even during the night, a color may be different
from a visual impression of humans depending on light components from lighting
devices installed in a parking lot and illuminated advertisement devices installed onouter walls of neighboring commercial facilities.
問 3)
When supercooling cancellation is detected, the food temperature Th_2
immediately after the supercooling cancellation is equivalent to the freezing point of thefood item. Based on this temperature, the target temperature Tc_set in the chilled
room lower container is set to a temperature at which ice crystals can be melted to adegree without cellular damage, e.g., Th_2+2 °C (S9).

A refrigerator setting

temperature that allows ice crystals to melt to a degree without cellular damage isreferred to as an ice crystal melting refrigerator temperature.
Then, when the melting of the ice crystals generated in the food item iscompleted and the food temperature begins to rise, the target temperature Tc_set in thechilled room lower container is maintained at Th_2+2 °C until, for example, the foodtemperature Th rises to a temperature Th_2+1 °C at which whether ice crystals havemelted is determined, the temperature Th_2+1 being lower than the ice crystal melting
refrigerator temperature (S10). In order to create this situation, the temperature in
the chilled room lower container is raised by, for example, keeping a damper fully closed.
When the food temperature Th becomes Th_2+1 °C or more after the supercoolingcancellation, checking for introduction and cancellation of supercooling is continued
with the control of S1-S8 again.