Korea Railroad Research Institute | Date: 2016-02-23
A charging apparatus for unmanned aerial vehicles and a charging method thereof. The charging apparatus includes: a transmit coil provided to a charging station and generating a magnetic field; a reception coil generating induced electromotive force according to variation of magnetic flux of the transmit coil; a reception coil adjuster adjusting at least one of an inclination and an orientation of the reception coil; and a controller controlling at least one of the inclination and the orientation of the reception coil by controlling the reception coil adjuster according to magnitude of the induced electromotive force generated in the reception coil by the magnetic field generated in the transmit coil.
Korea Railroad Research Institute | Date: 2016-08-11
A method of Mission Critical Push to Talk (MCPTT) service performed by a mobile terminal includes: generating, at the mobile terminal, a group call announcement for off-network Mission Critical Push to Talk (MCPTT) service, the group call announcement for off-network MCPTT service including information of a period of the group call announcement for off-network MCPTT service; controlling a transceiver to periodically transmit, to one or more mobile terminals, the group call announcement for off-network MCPTT service based on the period; in response to the transmitted group call announcement for off-network MCPTT service, receiving a response from the one or more mobile terminals; and establishing, based on the response from the one or more mobile terminals, a group call with the one or more mobile terminals by setting a direct wireless communication with the one or more mobile terminals.
Korea Railroad Research Institute | Date: 2017-03-15
A train scheduling method of an intelligent train scheduling system included obtaining train schedule information which includes train line information and information about operation time of each train; generating a time extension network which includes stations, as nodes, at which the trains included in the train schedule information stop, lines, as edges, between the stations included in the train schedule information, and operation time information of each train included in the train schedule information; and calculating predictive information about a traffic volume in each section and a traffic volume of each train for the train schedule on the basis of the time extension network.
Korea Railroad Research Institute | Date: 2017-01-04
By supporting a space generated by a settlement of the track bed gravel or asphalt roadbed underneath a concrete rail tie with cylindrical rods, and installing the present invention, one each separately, on the left and right sides of the concrete rail tie, recovery from settlements is automatic, and the response to differential settlements of the left and right rails of the track due to the train load can be easily facilitated, and by installing pressure reducing valves on the upper part of the concrete rail ties, pressure can be reduced while maintaining the track system as is without having to dismantle the concrete rail ties, and accordingly the usability of the concrete rail ties can be improved.
Korea Railroad Research Institute | Date: 2017-02-13
A wireless sensor device includes: an energy harvester configured to convert vibration generated from a broadband vibration source into electricity, an elastic member arranged to receive the vibration and a communication unit fixed by the elastic member, supplied with the converted electricity from the energy harvester, and configured to transmit sensing information obtained by sensing a measurement target. The elastic member operates as a mechanical filter configured to limit a frequency range and an acceleration magnitude of the vibration to be transferred to the communication unit for stabilizing the performance of the communication unit, and the communication unit is arranged to receive vibration passing through the elastic member.
Korea Railroad Research Institute | Date: 2016-03-17
Provided is a method for retransmitting received data using index coding and statistical characteristics in a method for transmitting packets, by a transmitter, to at least two receivers in a wireless communication network and retransmitting packets which are not received correctly by each receiver, wherein the transmitter receives a reception acknowledgement response signal for the packets transmitted to the receiver and analyzes received patterns of the reception acknowledgement response signals transmitted from the receiver to differently perform index coding for each received pattern on the packets which are not received correctly by the receiver and retransmit the index-coded packets. According to the exemplary embodiment of the present invention, it is possible to effectively reduce a retransmission frequency of the packets which are not received correctly and a channel use frequency on communications and effectively use limited radio resources.
Korea Railroad Research Institute | Date: 2015-10-30
A railroad vehicle monitoring system installed on a railroad vehicle includes: wireless sensor devices installed at attached equipment of the railroad vehicle, including a sensor that senses statuses of the attached equipment, configured to wirelessly transmit a sensing value sensed by the sensor in real time, and including an energy harvester configured to convert energy generated by running of the railroad vehicle into electric energy, and supply the electric energy as a power source for the sensor, a signal process in the sensing value, and wireless communication of the sensing value; sink node devices configured to wirelessly receive the sensing value and output, in real time, railroad vehicle status information obtained by integrating the received sensing value; and a vehicle status monitoring device configured to receive the railroad vehicle status information, integrate and manage the railroad vehicle status information, and output the integrated railroad vehicle status information in real time.
Korea Railroad Research Institute | Date: 2015-05-06
A cartridge for tunnel blasting is provided. A cartridge for tunnel blasting, which easily breaks a rock, by inserting a cartridge containing water into a bore hole formed in a rock by using a boring device, and injecting liquid nitrogen into the inserted cartridge, so as to induce cracks of the rock by using the characteristic of the water that expands when it is frozen.
Korea Railroad Research Institute | Date: 2015-08-12
The present invention relates to a two-phase, two-column linear pulse motor propulsion system, and more particularly to a two-phase, two-column linear pulse motor propulsion system which can implement high-speed driving, stopping, and switching directions forward/backward through non-adhesive driving characteristics by improving accelerating performance and torque performance. The two-phase, two-column linear pulse motor propulsion system comprises a field unit 121, 122 prepared in two columns in the longitudinal direction under a moving body 110 so as to generate a magnetic field; an armature unit 131, 132 which is prepared on a travelling track, generates a shifting field by the power supplied from a power conversion device, is prepared in two columns so as to correspond to the two-column field unit 121, 122 and generates the propulsion force of the moving body 110 through interaction due to a two-phase synchronous signal. Thus, it can improve propulsion force and acceleration/deceleration performance, compared to a linear propulsion system with one phase.
Korea Railroad Research Institute | Date: 2015-08-19
Disclosed is a bedrock crack apparatus using a powder keg type ice explosive wherein a via hole is formed at a bedrock using a via hole apparatus, and a sealed tube filled with water and a liquid nitrogen is inserted in the interior of the via hole, thus causing cracks in the bedrock based on the principle where volume expands when water is frozen and easily cracking the bedrock. The above bedrock crack apparatus may include a packer which is fixedly inserted in the mouth of a via hole formed at a bedrock; an inner tube which is disposed at the packer and is filled with water; an injection device which is connected to the packer; a nitrogen injection nozzle which is installed at the injection device and passes through the packer; and a supply unit which is connected to the injection device to supply liquid nitrogen.