A refrigerator includes a heat-insulating housing and at least one heat-insulating door fastened thereto. The semiconductor layer has, in at least the upper portion thereof, highly-resistive regions selectively formed to have a high resistance. Idle counts occurring during execution of code are collected. However, conventional techniques developed for silicon devices are not compatible with processing techniques for Group III-V compound semiconductors, such as gallium arsenide. The second execution unit is configured to perform an operation defined by the instruction and write the result to the register file. The system includes a transmission line structure including three or more elongated transmission elements each having two distal ends.