• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.462-466
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• 2002

This paper describes a low frequency electrical nerve stimulator for muscle care. The developed system consist of 8bit low power consumed MPU, voltage boosting circuit converting 9V input to 120V output, repairing circuit for distorted output pulse, LED and buttons for I/O, and electro-chemical pad. The pulse generation algorithm for the muscle care effect is developed with basic pulses such as a single phase rectangle pulse, symmetric rectangle pulse, and depolarized interrupt pulse.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.05a
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• pp.15-20
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• 1999

In this study, the effects of the maximum grit depth of cut on the grinding characteristics were investigated. And AE signals produced during grinding processes have been studied to find out the appropriate AE parameters for assessing grinding processes. S45C steel has been ground under the conditions yielding removal rate of workpiece, 100, 200, 300 and 400rnm$^3$/min which was achived by altering workpiece velocity($\upsilon$) and apparent depth of cut(Z). According to the experimental results, the value of surface roughness increases but grinding power, energy rate of AE signal(AErms$^2$) and specific grinding energy consumed decrease with increase of the maximum grit depth of cut.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.400-405
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• 2005

The vertical slope of railway track is the differences of attitude for the horizontal distances between two positions of railway. It is better to be small vertical slope for the comfortable of passengers and the operation of railway system. However, the variable vertical slope is required that the simple vertical slope causes the huge quantities of embankment and cutting, the continuous welded rail tunnels, the continuous welded rail bridges, etc,. This research is for the relation between the vertical slopes and the trainset performances. This research shows that the effective vertical slopes for the operation of railway. The velocity of car and operation time and the consumed energy was considered for each vertical slope and type of car power system. The result of suitable vertical slope from this research is to be used for the design of railway plan.

• Proceedings of the KSR Conference
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• 2002.05a
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• pp.399-403
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• 2002

The transmission system of high speed train serve in the severe condition compared with those of other trains, namely, they have to transmit high power to run with high speed and they have to make maximum use of the limited space. To clarify the strength of gear for Korea High-Speed Train, a bending fatigue test of gear specimen is performed and compare with actual gear's. From this result, specimen test is useful to infer S-N curve and endurance limit of actual gear that much time and expense are consumed.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.11
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• pp.1072-1078
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• 2001

The real time optimal control algorithm of the DDC controller for chilled water and supply air temperature set-point of heating, ventilating, air-conditioning and refrigeration systems has been researched for minimization of the total power which is consumed by the chiller, chilled water pump and air handing unit fan. The study has been done by using TRNSYS program in order to analyze the central cooling system in terms of the environmental variables such as indoor cooling lead and wet-bulb temperature. This optimal control alogorithm saves more energy and is suitable for real time on-line control in comparison with conventional method.

• Journal of the Korean Society of Industry Convergence
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• v.22 no.1
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• pp.29-37
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• 2019

A new permanent magnet biased hybrid maglev actuator is developed. Compared to the classical hybrid maglev actuators, the new maglev has unique flux paths such that bias fluxes are separated with control flux paths. The control flux paths have minimum reluctances only developed by air gaps, so the currents to produce control fluxes can be minimized. The consumed power to operate this maglev system can also be minimized. The gravity load can be compensated with the static magnetic forces developed by the permanent magnet bias fluxes while external disturbances are controlled with the bidirectional AC magnetic forces developed by control fluxes by currents. 1-D circuit model is developed for this model such that the flux densities and magnetic forces are extensively analyzed. 3-D finite element model is also developed to analyze the performances of the maglev actuator.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.6
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• pp.131-137
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• 2010

Change of the energy used in a house can be separated from LNG, and electric power. The electric power consumption of a house is more increasing than LNG. The interest for electric houses is rising due to energy saving and low carbon emission. Accordingly, the amount of energies and cost are analyzed consumed in a house using cumulative energy consumption. The result of analysis, amount of electric power, is more increase. In comparison, the use volume of city gas is more decrease. In this paper, the use volume of energy resource is analyzed using historical energy consumption data in the past 25 years. In addition, expected electrical power and heating energy is analysed adopting an Electric Residence.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.298-302
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• 2009

Low power Hall thruster is under development as one of the core technologies for STSAT-3. The Hall thruster has several advantages such as its simple structure, high thrust density and specific impulse etc. Development target values deduced by analyzing requirements are consumed electrical power, thrust, thrust efficiency, and specific impulse of < 300 W, > 10 mN, ~ 35%, and > 1000 s, respectively. In order to achieve the target specifications, two prototype Hall thrusters were developed and compared. To date, thrust and efficiency are 11 mN and 37% under the total power of 290 W with 0.97 mg/s Xe propellent supply.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.2
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• pp.179-184
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• 2016

The electrical load testing system developed from this study was designed to control rated-capacity-testing or variable-load-testing in an active and precise manner and save electric energy during testing, and also to convert the saved electric energy through the electrical load testing system to grid line. As for the device under testing, it was designed to be applied to not only transformer, rectifier, voltage regulator, inverter which require grid voltage source but, also applied to electric power, aerogenerator, photovoltaic, hybrid generator, battery, etc. which do not require grid voltage source. The system was designed to return the power consumed during the testing to the grid line by connecting the synchronizing pwm inverter circuit to the grid voltage source, and was also made to enable the being-tested system from disuse of approximately 93.4% energy when compared to the conventional load testing system which has used the passive resistor.

• Journal of the Korea Society of Computer and Information
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• v.16 no.10
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• pp.197-203
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• 2011

In this paper, a new cluster configuration process is proposed. The energy consumption of sensor nodes is reduced by configuring the initial setup process only once with keeping the initial cluster. Selecting the highest power consumed node of the member nodes within the cluster to the header of next round can distribute power consumption of all nodes in the cluster evenly. With this proposed way, the lifetime of the USN is increased by the reduced energy consumption of all nodes in the cluster. Also, evenly distributed power consumptions of sensors are designed to improve the energy hole problem. The effectiveness of the proposed algorithms is confirmed through simulations.