受験番号：24IPE001問１）
1.

An AC arc welding device comprising:a welding control unit;
a memory unit;
an AC frequency setting unit that sets an AC frequency;
a reversed polarity period setting unit that sets a reversed polarity period;a calculation unit that calculates a straight polarity period and a reversed

polarity period and outputs them to the welding control unit; anda selection unit that selects one of a plurality of outputs of the memory unit
and outputs it to the calculation unit,
wherein the welding control unit conducts a straight polarity base current
that is lower than a peak current of the straight polarity period before a polarity
reversal when the straight polarity period finishes, and conducts a reversed polarity
base current that is lower than a peak current of the reversed polarity period beforea polarity reversal when the reversed polarity period finishes,
wherein the memory unit(a) stores a plurality of combinations of a straight polarity base ratio that is aratio of a period during which the straight polarity base current is conducted during
the straight polarity period, and a reversed polarity base ratio that is a ratio of aperiod during which the reversed polarity base current is conducted during thereversed polarity period, or(b) stores a plurality of combinations of a straight polarity peak period that isa period during which the peak current is conducted during the straight polarity
period, a straight polarity base period that is a period during which the straightpolarity base current is conducted, a reversed polarity peak period that is a period
during which the peak current is conducted during the reversed polarity period, anda reversed polarity base period that is a period during which the reversed polarity
base current is conducted, andwherein the selection unit is configured to select one of the plurality of
combinations stored in the memory unit based on an inductance on a welding loadside.

問２）
In a conventional surveillance system where the sensor is installed, for example, at
a gate of a parking lot, when a vehicle is detected at the gate, the mobile robot
arrives at the gate where the sensor is installed. The robot processes thephotographs it has taken on the way, determines the body color of the vehicle, andcan then transmit that information to a control center. In such a case, it is desirable
that the surveillance system can take photographs that provide information usefulin identifying the vehicle.
However, depending on the personality of the thief and state of the parking lot, theway the vehicle will be parked cannot be predicted in advance. It may therefore bedifficult for the mobile robot to photograph the vehicle such that the body color of
the vehicle can be determined.
For example, when photographing a vehicle using a visible light color camera to
determine the body color, its hue may differ between photographs obtained in thedaytime and photographs obtained in the evening due to the influence of thesunlight, such that a white vehicle may appear orange when photographed in theevening. There was also a problem in that during nighttime, light components fromlighting systems installed at the parking lot, electronic billboards installed on thewalls of nearby commercial buildings and the like could cause a hue that looked
different than when observed with the naked eye.

問３）
When supercooling interruption is detected, the food temperature

Th_2

immediately after the supercooling was interrupted corresponds to the freezing
point of the food. Based on this temperature, the target temperature Tc_set in thebottom container of the chilling compartment is set to a temperature capable ofmelting ice crystals without cell damage, for example Th_2 + 2°C (S9). Such a set
temperature of the refrigerator interior capable of melting ice crystals without cell
damage is referred to herein as an ice crystal-melting refrigerator interiortemperature.
Next, when melting of the ice crystals that formed in the food is finished and thefood temperature begins to rise, the target temperature Tc_set of the bottomcontainer of the chilling compartment is maintained at Th_2 + 2°C until for example
the food temperature Th rises to a temperature Th_2 + 1°C which is lower than theice crystal-melting refrigerator interior temperature and at which melting of ice
crystals is determined (S10). To create this state, the temperature in the bottom
container of the chilling compartment is increased, by for example maintaining thedamper in a completely closed state. When the food temperature Th after
supercooling interruption becomes equal to or greater than Th_2 + 1°C,
supercooling introduction and checking for the occurrence of supercoolinginterruption is resumed again by the control process of steps S1 to S8.