受験番号：24IPE003

問１）
What is claimed is:1.

An alternating current arc welding apparatus, comprising:a welding controlling unit;
a memory unit;
an alternating current frequency setting unit that sets an alternating current
frequency;
a negative polarity period setting unit that sets a negative-polarity period;a calculation unit that calculates a positive-polarity period and thenegative-polarityperiod

andoutputs

thepositive-polarity

periodandthenegative-polarity period to the welding controlling unit; anda selection unit that selects one output from outputs of the memory unit andoutputs the one output to the calculation unit,
wherein the welding controlling unit causes a positive-polarity base current
lower than a peak current at the positive-polarity period to flow before polarity reversal
during which the positive-polarity period is finished and causes a negative-polarity basecurrent lower than a peak current at the negative-polarity period to flow before polarity
reversal during which the negative-polarity period is finished,
wherein the memory unit stores (a) a plurality of sets of a positive-polarity baseratio that is a ratio of a period during which the positive-polarity base current flows at
the positive-polarity period and a negative-polarity base ratio that is a ratio of a period
during which the negative-polarity base current flows at the negative-polarity period, orstores (b) a plurality of sets of a positive-polarity peak period that is a period during
which the peak current flows at the positive-polarity period, a positive-polarity baseperiod that is a period during which the positive-polarity base current flows, anegative-polarity peak period that is a period during which the peak current flows at
the negative-polarity period, and a negative-polarity base period that is a period during
which the negative-polarity base current flows, andwherein the selection unit selects one set from the plurality of the sets stored in
the memory unit on the basis of an inductance on a welding load side.
問２）
For example, in the case where a sensor is installed on a gate of a parking lot, it
is possible for a conventional monitoring system to detect an automobile at the gate, toprocess an image captured by a mobile robot until the mobile robot arrives at the gateon which the sensor is installed, to identify the color of the automobile, and to send thisinformation to a center. At this time, the monitoring system preferably captures theimage such that information useful to identify the automobile can be obtained.
However, how to park an automobile depends on, for example, the character ofa thief and the conditions of the parking lot and cannot be expected. Accordingly, insome cases, it is difficult for the mobile robot to capture the image of the automobile
such that the color of the automobile can be identified.
For example, the image of an automobile is captured by using a visible-lightcolor camera to identify the color of the automobile. However, the color is affected by
the sunlight and varies between the case where the image is captured during daytime
and the case where the image is captured during evening, and in the case where theimage is captured during night, there is a possibility that the color is incorrectly
identified to be orange even when the actual color of the automobile is white. In thecase of night, there is a possibility that the color is identified to be different from thecolor perceived by visual observation depending on lighting equipment installed in theparking lot and light components from an illuminated advertisement placed on an outerwall of a neighboring commercial building. There are such problems.
問３）
When the release of the excessive cooling is detected, the temperature Th_2 ofthe food right after the release of the excessive cooling corresponds to the freezing pointof the food. The target temperature Tc_set in the lower container in the chilled room is
set on the basis of this temperature to a temperature at which the ice crystals can bemelted without a cell damage, for example, Th_2 + 2 [°C] (S9).

A predetermined

temperature inside the refrigerator at which the ice crystals can be melted without acell damage is referred to as an ice-crystal melting temperature inside the refrigerator.
Subsequently, when the melting of the ice crystals in the food is finished andthe temperature of the food starts to increase, for example, until the temperature Th ofthe food increases to a temperature of Th_2 + 1 [°C] that is lower than the ice-crystal
melting temperature inside the refrigerator and at which the melting of the ice crystals
is determined, the target temperature Tc_set of the lower container in the chilled room
is maintained at Th_2 + 2 [°C] (S10). To make this state, for example, a state where
the dumper is fully closed is maintained to increase the temperature in the lower
container in the chilled room. After the temperature Th of the food after the release of
the excessive cooling becomes Th_2 + 1 [°C] or more, the control S1 to S8 is continued

again to check the presence or absence of the introduction of the excessive cooling andthe release of the excessive cooling.