Abstract: Provided is a method of transmitting and receiving a message using an encryption/decryption key, by which each of a sender and a recipient can generate an encryption/decryption key and recover a key used for encryption/decryption while transmitting and receiving the message using an electronic device. The method includes: (a) a user generating his/her own private key and a public key, registering the public key with a key recovery agent (KRA), and setting shared secret information; and (b) a sender transmitting the recovery information necessary for decryption of the transmission message to a recipient, and the recipient generating a key necessary for the decryption from the recovery information and decrypting the transmission message. The method may further include the recipient requesting recovery of the session key to the KRA.

Abstract: A network apparatus and packet routing method for ubiquitous computing are provided. In the network apparatus, a movement detection unit detects movement from a first network to a second network, and a movement address setting unit generates care-of-address (CoA) information corresponding to prefix information of the second network. A movement registration unit registers a movement address by transmitting a binding update message containing the generated CoA and home address (HoA) mapping information, to a home agent. A resource setting unit registers information on current terminal apparatuses among network terminal apparatuses on the second network. A packet distribution unit distributes the received packet to a current terminal apparatus corresponding to the application characteristic of the packet received from the home agent based on the information on the current terminal apparatuses.

Abstract: An apparatus for testing a display device includes a display device to display test patterns, a graphic process unit to supply analog mode signals and digital mode signals to the display device, and a control unit to allow test patterns of an analog testing mode and test patterns of a digital testing mode to be sequentially displayed on the display device upon receiving a control signal from the graphic process unit, and to output a control signal to the display device to sequentially change display characteristics of an image according to an on-screen-display mode testing menus.

Abstract: Disclosed is automatic fluid pressure-intensifying apparatus and method of a hydraulic traveling device for increasing a traveling capability or a pulling capability of a heavy equipment by changing a relief pressure in a hydraulic circuit under the state that a working device of the heavy equipment does not operate and a traveling device only operates. In the automatic fluid pressure-intensifying apparatus of the hydraulic traveling device, a first control valve selectively changes a flow direction of a hydraulic fluid being supplied by a hydraulic pump toward a traveling motor of the heavy equipment. Further, a second control valve selectively changes the flow direction of the hydraulic fluid being supplied by the hydraulic pump toward a working device of the heavy equipment. A relief valve restricts an allowable maximum pressure in a hydraulic circuit.

Abstract: Disclosed is an apparatus for increasing the operating capability of a construction machine during a fine operation mode and a method for the same. The apparatus being capable of preventing a merged hydraulic fluid from being supplied into a hydraulic actuator and increasing the pressure of the hydraulic fluid being supplied into the hydraulic actuator during the fine operation mode. The apparatus includes a detector that detects the RPM count of the engine of the construction machine and determines whether the engine is switched into the fine operation mode. A first anti-confluence valve and a second anti-confluence valve prevent a first hydraulic fluid supplied into the first actuator and a second hydraulic fluid supplied into the second actuator from merging while either the first actuator or the second actuator is operating. An anti-confluence relay turns the first anti-confluence valve and the second anti-confluence valve on/off.

Abstract: A device for controlling a breaker in construction vehicles is disclosed. The device includes a control circuit provided with a power supply, a first solenoid valve used for controlling the breaker, and a second solenoid valve used for boosting the relief pressure of the circuit. The device also includes a control switch and a select switch. The control switch is installed in a control lever and is handled by an operator in order to selectively open or close the control circuit. Meanwhile, the select switch is connected between the control switch, power supply and first and second solenoid valves. The select switch selectively connects the power supply to the first or second solenoid valve in order to select either of the breaker and pressure boosting operations, which are commonly controlled by the control switch.

Abstract: A control device for a travelling system in construction vehicles is disclosed. The control device applies the pilot pressure of the pilot pump to the spool of the directional control valve separately from the travelling control pedal, thus automatically controlling operation of the directional control valve. However, the manual control mode performed by the travelling control pedals has priority over the automatic control mode. The control device has a proportional control valve, which applies the pilot pressure of the pilot pump to the spool in response to an input current signal. A pressure sensor checks the pilot pressures, which are generated by both the travelling control pedals and the proportional control valves and act on the spool. A controller receives a signal indicative of the pilot pressures checked by the pressure sensor and outputs the current signal to the proportional control valve.