受験番号：24IPE006

問１）

1. An alternating-current arc welding device comprising:a welding control unit;
a storage unit;
an alternating-current frequency setting unit which sets
an alternating-current frequency;
a reverse polarity period setting unit which sets areverse polarity period;a calculation unit which calculates and outputs astraight polarity period and the reverse polarity period to thewelding control unit; anda selection unit which selects and outputs one of aplurality of outputs from the storage unit to the calculation
unit,
wherein:the welding control unit is configured to cause a straightpolarity base current smaller than a peak current of thestraight polarity period to flow before polarity reversal when
the straight polarity period is completed, and configured tocause a reverse polarity base current smaller than a peakcurrent of the reverse polarity period to flow before polarity
reversal when the reverse polarity period is completed;the storage unit is configured to store(a) a plurality of combinations of a straight polarity
base ratio which is a ratio of a period in the straight polarity
period in which the straight polarity base current is caused
to flow, and a reverse polarity base ratio which is a ratio ofa period in the reverse polarity period in which the reverse
polarity base current is caused to flow, or(b) a plurality of combinations of a straight polarity
peak period which is a period in the straight polarity period
in which the peak current is caused to flow, a straight polarity
base period which is the period in which the straight polarity
base current is caused to flow, a reverse polarity peak period

which is a period in the reverse polarity period in which thepeak current is caused to flow, and a reverse polarity baseperiod which is the period in which the reverse polarity basecurrent is caused to flow; andthe selection unit is configured to select one of theplurality of combinations stored in the storage unit, based on
an inductance on a welding load side.
問 2）

(A)
In the conventional monitoring system, a sensor may be installedat the parking lot gate. If a vehicle is detected at the gate,
the mobile robot can come to the gate where the sensor isinstalled, process images captured on the way, distinguish thebody color of the vehicle, and transmit the information to acenter.
In this case, the monitoring system preferably
captures images which provide information useful for
identifying the vehicle.
However, the manner in which the vehicle is parked may
differ depending on the character of the thief or the situationof the parking lot, for example, and cannot be predicted.
Accordingly, it may be difficult for the mobile robot to capture
an image of the automobile so that the body color of the vehicle
can be identified.
For example, when the vehicle is captured using a color,visible-light camera to distinguish the body color, an image
captured during daytime and an image obtained in the evening
may have different color tones due to the influence of sunlight.
As a result, a white vehicle may be determined to be orange whenphotographed in the evening. At night time, the captured image
may appear to have a color tone different from the color as viewed
by the human eye, depending on light components fromillumination equipment installed in the parking lot,
advertising illuminations installed on the walls of nearby
commercial facilities, and so on.
(A)’問 3）(B)When a removal of supercooling is detected, the foodtemperature Th_2 immediately after the removal of supercoolingcorresponds to the freezing point of the food. Based on thistemperature, the target temperature Tc_set in the chilledchamber lower container is set to a temperature such that theice crystals can be melted without cell damage, such as to Th_2+ 2[°C](S9). The internal set temperature at which ice crystals
can be melted without cell damage is referred to as the ice
crystal melting internal temperature.
Then, as the melting of ice crystals formed in the foodends and the food temperature begins to increase, the target
temperature Tc_set in the chilled chamber lower container ismaintained at Th_2 + 2[°C](S10) until, e.g., the foodtemperature Th increases to a temperature Th_2 + 1[°C] which
is lower than the ice crystal melting internal temperature andat which the ice crystals are determined to have melted. Inorder to obtain this state, the damper is maintained infull-closed state, for example, so as to increase thetemperature in the chilled chamber lower container. When thefood temperature Th after removal of supercooling becomes Th_2
+ 1[°C] or higher, the confirmation of the presence or absenceof introduction of supercooling or removal of supercooling isagain continued through the control from S1 to S8.
(B’)