Abstract: Provided is an air conditioning system which can automatically switch the operating mode of at least one indoor unit based on the difference between a measured indoor temperature provided by an indoor temperature sensor and a predefined set indoor temperature and then set a new set indoor temperature. The air conditioning system does not require a user to manually switch the operating mode of the indoor unit, thereby maximizing user convenience. In addition, the air conditioning system can maintain optimum room temperature.

Abstract: In an air conditioning system, a first controller converts the communication method of an external command inputted into the second controller and transmits the same to an air conditioner. Further, the first controller displays operating information of the air conditioner. Accordingly, the structure of the air conditioning system is simplified, and installation costs are reduced.

Abstract: A semiconductor memory device according to embodiments of the invention includes N channels for interface with an outside. During a test mode where the semiconductor memory device is tested by a tester having M channels, K ones of the N channels of the memory device are connected to the M channels of the tester, N being more than M and M being equal to or more than R*K (where R is an integer).

Abstract: A method of transmitting and receiving a plurality of signals over a single transmission line in a semiconductor device and a semiconductor device are provided. The method includes encoding a plurality of original signals into signals having different pulse widths, combining the plurality of encoded signals into one signal and transmitting the one combined signal over the single transmission line, and receiving the combined signal and decoding the combined signal into the plurality of original signals.

Abstract: A semiconductor memory device according to embodiments of the invention includes N channels for interface with an outside. During a test mode where the semiconductor memory device is tested by a tester having M channels, K ones of the N channels of the memory device are connected to the M channels of the tester, N being more than M and M being equal to or more than R*K (where R is an integer).

Abstract: Provided is a pressure-balanced underwater acoustic transducer. The transducer includes an oscillator unit having an oscillator oscillating by an electrical signal supplied to electrodes, provided on its surface, a sound transmission material for transmitting sound from the oscillator, provided at its periphery, and a transducer housing provided at the exterior of the sound transmission material, a sound reflector positioned over the oscillator unit, for reflecting sound propagated from the oscillator, a water entry layer formed at a space between the oscillator unit and the sound reflector to allow water to enter and exit to the rear window of the oscillator, thereby leading to a balanced state of pressures applied to the front and rear windows of the oscillator, and a phase combiner for combining sound reflected from the sound reflector and straight traveling sound generated from the front window of the oscillator into one single phase.

Abstract: Provided is a pressure-balanced underwater acoustic transducer. The transducer includes an oscillator unit having an oscillator oscillating by an electrical signal supplied to electrodes, provided on its surface, a sound transmission material for transmitting sound from the oscillator, provided at its periphery, and a transducer housing provided at the exterior of the sound transmission material, a sound reflector positioned over the oscillator unit, for reflecting sound propagated from the oscillator, a water entry layer formed at a space between the oscillator unit and the sound reflector to allow water to enter and exit to the rear window of the oscillator, thereby leading to a balanced state of pressures applied to the front and rear windows of the oscillator, and a phase combiner for combining sound reflected from the sound reflector and straight traveling sound generated from the front window of the oscillator into one single phase.