受験番号：24IPE016

問１）

What is claimed is:
1. An alternating-current arc welding apparatus, comprising:a welding control unit;
a storage unit;
an alternating-current frequency setting unit that sets an alternating-current
frequency;
a reverse polarity period setting unit that sets a reverse polarity period;a calculation unit that calculates a normal polarity period and a reverse polarity
period, and outputs the normal polarity period and the reverse polarity period to thewelding control unit; anda selection unit that selects one of a plurality of outputs from the storage unit,
and outputs the one of the plurality of outputs to the calculation unit,
wherein the welding control unit is configured to cause a base current of
normal polarity lower than a peak current of the normal polarity period to flow before
reversal of polarity when the normal polarity period ends, and to cause a base current ofreverse polarity lower than a peak current of the reverse polarity period to flow before
reversal of polarity when the reverse polarity period ends, andwherein the storage unit is configured(a) to store a plurality of combinations of a base ratio of normal polarity, whichis the ratio of a period in which the base current of normal polarity flows in the normal
polarity period, and a base ratio of reverse polarity, which is the ratio of a period inwhich the base current of reverse polarity flows in the reverse polarity period, or(b) to store a plurality of combinations of a peak period of normal polarity,
which is a period in which the peak current in the normal polarity period flows, a baseperiod of normal polarity, which is a period in which the base current of normal polarity
flows, a peak period of reverse polarity, which is a period in which the peak current in
the reverse polarity period flows, and a base period of reverse polarity, which is a period
in which the base current of reverse polarity flows, andwherein the selection unit is configured to select, based on an
welding-load-side inductance, one of the plurality of combinations stored in the storage
unit.

問２）

In conventional monitor systems, for example, when a sensor has been set at agate of a parking lot, a car is detected at the gate, and a movable robot arrives at the gate
where the sensor is set. The robot can identify the color of the body of the car byprocessing images obtained by imaging while moving to the gate, and send information
about the color to a center. In this case, it is preferable that the monitor system performs
imaging so that useful information for identifying the car is obtainable.
However, the method for parking a car depends on the character of a thief, thecondition of a parking lot or the like, and is not predictable. Therefore, in some cases, it
is difficult for the movable robot to image a car so that the color of the body of the car isdistinguishable.
For example, even when a car is imaged by using a visible light camera forcolor imaging to identify the color of the body of the car, the hue of an image obtainedin the daytime and the hue of an image obtained at dusk are different because of theeffect of sun light. Therefore, even if the color of the car is white, if the car is imaged atdusk, the color may be identified as orange. Further, there has been a problem that thehue may give a different impression from a color observed by human eyes also at night
depending on a lighting device set in a parking lot and light components from adecorative advertisement apparatus set on an outer wall of nearby commercial facilities.
問３）
Next, when cancellation of supercooling is detected, temperature Th_2 of thefood immediately after cancellation of supercooling corresponds to the freezing point of
the food. Target temperature Tc_set in a lower container of a chilled room is set, basedon this temperature, at a temperature, e.g., Th_2+2 [°C], at which ice crystals aremeltable in such a manner that cells of the food are not damaged (S9). Here, atemperature set for the inside of the refrigerator so that ice crystals are meltable insuch a manner that cells of the food are not damaged will be referred to as an ice crystal
melt refrigerator inside temperature.
Next, when melt of ice crystals occurred in the food ends and the temperatureof the food starts rising, target temperature Tc_set of the lower container of the chilledroom is maintained at Th_2+2 [°C], for example, until the temperature Th of the foodrises to Th_2+1 [°C], which is lower than the ice crystal melt refrigerator insidetemperature, and at which melt of ice crystals is judged (S10). To form this condition,
the temperature of the lower container of the chilled room is increased, for example, bykeeping a damper in a fully opened state. When the temperature Th of the food aftercancellation of supercooling becomes Th_2+1 [°C] or higher, presence of introduction ofsupercooling and cancellation of supercooling is continuously checked again byperforming control in S1 through S8.