Abstract: A security method and a security apparatus are disclosed which use a self-generated encryption key. The security method includes the steps of: generating an encryption key; decrypting pre-encrypted data using a pre-stored manufacturer key; and re-encrypting the decrypted data using the encryption key. The security method and apparatus minimize external leakage of data by self-generating the unique encryption key. Since the encryption keys are unique in each set, set binding is possible.

Abstract: An audio and video synchronization compensation method and apparatus for smoothly compensating audio and video synchronization in an audio and video system such as a DTV and a DVD player are provided. The apparatus includes a signal decoder unit which extracts time information for reproducing a video and/or audio signal and reference operation time information of a reproduction system from an input compressed stream; a signal synchronization control unit which determines the reproduction state of a signal by comparing reproduction time information of the stream with reference time information of the system, measures the difference between the reproduction time information and the reference time information in the determined signal reproduction state, and adjusts a transition speed used to approach from a signal reproduction interval to a signal synchronization interval according to a reproduction speed value of a pattern corresponding to the difference.

Abstract: An audio system apparatus and method for processing multi-channel audio data are provided. In the audio system, information indicating a correspondence relation between the channels of the multi-channel audio data and speakers installed in an arbitrary space is generated based on selection by a user, and according to the generated information, the channels of the multi-channel audio data are rearranged. By doing so, terminals of the output panel of the audio system and speakers can be connected arbitrarily according to convenience of a user and channels of multi-channel audio data can be set appropriately to the connection status.

Abstract: A cyclone dust collector and a vacuum cleaner having the same. The cyclone dust collector has a cyclone body shaped to have a relatively wider upper portion and a relatively narrower lower portion and also has a suction port and a discharge port, a grill member connected to the discharge port, a dust receptacle connected to the cyclone body, and a blocking member for partially blocking the grill member. Air drawn in through the suction port moves in an increasingly wider radial path as it travels upwardly to the discharge port, increasing the centrifugal force on suspended particles as they travel toward the discharge port. The shape of the cyclone body prevents turbulent flow from being generated. Dust is prevented by the blocking member from attaching to the grill member before being centrifuged, performance of the grill member is enhanced.

Abstract: Disclosed is a method for detecting a fault by using harmonics and a state transition diagram. When the fault occurs on transmission lines, the fault is detected by using harmonics and the state transition diagram. Two logic signals are outputted by using apparent impedance of a steady state characteristic and a sum of harmonics components of a transient state characteristic. Such two logic signals are used as input parameters of the state transition diagram so that the state of an electric power system is presumed based on a state transition of the electric power system. It is possible to prevent a distance relay from being malfunctioned under an increase of load and unstable voltage. The state of the electric power system is presumed by using harmonics and the state transition diagram, and the fault on the transmission line is reliably detected.

Abstract: Disclosed is a method for detecting a fault by using harmonics and a state transition diagram. When the fault occurs on transmission lines, the fault is detected by using harmonics and the state transition diagram. Two logic signals are outputted by using apparent impedance of a steady state characteristic and a sum of harmonics components of a transient state characteristic. Such two logic signals are used as input parameters of the state transition diagram so that the state of an electric power system is presumed based on a state transition of the electric power system. It is possible to prevent a distance relay from being malfunctioned under an increase of load and unstable voltage. The state of the electric power system is presumed by using harmonics and the state transition diagram, and the fault on the transmission line is reliably detected.