• The Journal of the Korea Contents Association
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• v.12 no.9
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• pp.408-421
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• 2012

The purpose of this study was to verify differences in changes of physical self-concept between Taekwondo participation group and non Taekwondo participation group in order to meet the needs of the study the limitations of previous studies had to be considered. The participants were elementary students in S city selected by this researcher. 30 students were in the Taekwondo participation group and 40 students were in the non Taekwondo participation group decided by ACSM(15) exercise guide line standard, three times repetition measurements per 12 weeks were executed for $2{\times}3$ mixed design with repeated measure. For this statistic, SPSS 12.0 for windows was used for technical statistic, two-way ANOVA, paired t-test, and independent t-test. The results were as follows; First, there were differences of change pattern in physical self-concept generally between Taekwondo participation group and non Taekwondo participation group. Second, there was a difference between Taekwondo exercise group and non Taekwondo exercise group according to 1st and 2nd, 1st and 3rd measurement point partially. Third, there were differences between the Taekwondo exercise group and non Taekwondo exercise group on the 2nd and 3rd measurement. In conclusion, Taekwondo discipline tended to have a large effect increasing physical self-concept.

• Journal of the Korean Society for Railway
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• v.19 no.1
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• pp.38-45
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• 2016

The power transformation system of High Speed rolling stocks like KTX-Sancheon has shown excellent control capacities in the areas of riding comfortability, switching efficiency, safety and energy consumption due to technical developments in power-electronics, high speed & large scale integrated semiconductors and microprocessors. However, harmonics from IGBT, a high speed switching device used in the Convertor & Invertor equipment of rolling stocks have given rise to various problems in transformer substations, signaling systems, data transmission systems and facility monitoring systems. Especially, TI21 non-insulated track circuits have malfunctioned due to the influence of returning current harmonics which were generated at around of integer times of the number of power transformation equipment in the frequency domain. This paper, measures and analyzes various schemes to analyze the traveling path of the returning current harmonics generated due to the relationship between the rolling stocks and track circuits on site. Ultimately, theseschemes will be used to design high speed rolling stocks, AF track circuits and a common grounding network.

• Korean Journal of Optics and Photonics
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• v.22 no.1
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• pp.46-52
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• 2011

A confocal microscope was developed utilizing a scanning sample stage based on a home-built double-compound flexure guide. A scanning sample stage with nano-scale resolution consisted of a double leaf spring based flexure, a displacement amplifying lever, a Piezo-electric Transducer(PZT) actuator and capacitance sensors. The performance of the two-axis stage was analyzed using a commercial finite element method program prior to the implementation. A single line laser was employed as the light source along with the Photo Multiplier Tube(PMT) that served as the detector. The performance of the developed confocal microscope was evaluated with a mouse ear skin imaging test. The designed scanning stage enabled us to build the confocal microscope without the two optical scanning mirror modules that are essential in the conventional laser scanning confocal microscope. The elimination of the scanning mirror modules makes the optical design of the confocal microscope simpler and more compact than the conventional system.

• Solar Energy
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• v.15 no.3
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• pp.3-14
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• 1995

The Direct Contact heat Exchanger(DCHX) has been widely studied in the chemical industry for many years due to its inherent simplicity as a counter-current divice for heat and mass transfer. In many solar systems, the DCHX unit can be combined with the thermal storage unit, or alternatively, it can be used separately from the storage unit, much like an external(to storage) closed heat exchanger system. In the present work, the spray column type of direct contact heat exchangers are studied extensively to harness the solar energy for hot water and spaced heating. Some of the major considerations that are involved in the design of heat exchangers in this study are that : working fluid is a hydrocaabon(such as Texaterm) or water which is either lighter or heavier than storage medium. The experimental data have revealed some interesting characteristics concerning the application of DCHXs for solar energy utilization. These experiments are carried out in the line of solar heating system, major results are as follows : 1) the flow and aspect of working fluid drop for maxium heat transfer 2) efficiency and volumetric heat transfer coefficient of D.C.H.X with a heavier working fluid are higher than those of D.C.H.X with a lighter working fluid.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.6 s.348
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• pp.47-52
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• 2006

This paper proposes a novel low-power $32bit\times32bit$ multiplier for deep submicron technologies beyond 130nm. As technology becomes small, static power due to leakage current significantly increases, and it becomes comparable to dynamic power. Recently, shutdown method based on MTCMOS is widely used to reduce both dynamic and static power. However, it suffers from severe power line noise when restoring whole large-size functional block. Therefore, the proposed multiplier mitigates this noise by shutting down and waking up sequentially along with pipeline stage. Fabricated chip measurement results in $0.35{\mu}m$ technology and gate-transition-level simulation results in 130nm and 90nm technologies show that it consumes $66{\mu}W,\;13{\mu}W,\;and\;6{\mu}W$ in idle mode, respectively, and it reduces power consumption to $0.04%\sim0.08%$ of active mode. As technology becomes small, power reduction efficiency degrades in the conventional clock gating scheme, but the proposed multiplier does not.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.9
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• pp.1098-1106
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• 2007

This paper presents active antenna diplexers implemented into an ultra-wideband CPW(Coplanar Waveguide) fed monopole antennas. The proposed active antenna diplexer is designed to direct interconnect the output port of a wideband antenna to the input port of two active(HEMT) devices, where the impedance matching conditions of the proposed active integrated antenna are optimized by adjusting CPW(Coplanar Waveguide) feed line to be the length of 1/20 $\lambda_0$(@5.8 GHz) in planar type wideband antenna. The measured bandwidth of the active integrated antenna shows the range from 2.0 GHz to 3.1 GHz and from 5.25 GHz to 5.9 GHz. The measured peak gains are 17.0 dB at 2.4 GHz and 15.0 dB at 5.5 GHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.1
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• pp.1-10
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• 2013

In this paper, a broadband planar monopole antenna for multi-band services is proposed. The physical size of the proposed antenna is miniaturized by folding a rectangular loop. And a resonance point in the 3.9 GHz band is reduced by a coupling phenomenon with the central part of the T-shaped patch and the folded rectangular loop. In addition, the T-shaped patch is inserted to the rectangular shaped monopole antenna due to deriving the broadband frequency characteristics. The frequency characteristic is optimized by adjusting the gap and length of the folded rectangular loops and a transverse diameter of the T-shaped patch. The antenna dimensions including the ground plane are $40{\times}60{\times}1.6mm^3$. It is fabricated on the FR-4 substrate(${\epsilon}_r$=4.4) using a microstrip line of $50{\Omega}$ for impedance matching. In the measured result, the bandwidth corresponding to the VSWR of 2:1 is 162 MHz(815~977 MHz) and 2,530 MHz(1.43~3.96 GHz). For analyzing the human effect by the proposed antenna, 1 g and 10 g averaged SARs are simulated and measured. As the simulated results, 1 g-averaged SAR is 1.044 W/kg, and 10 g-averaged SAR is 0.718 W/kg. This result are satisfied by the SAR guidelines which are 1.6 W/kg(1 g-averaged) and 2.0 W/kg(10 g-averaged).

• Journal of the Korean GEO-environmental Society
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• v.6 no.4
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• pp.47-58
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• 2005

Development of underground space is conducted for various useful facility and underground structures and deep excavation technology for reclaimed area has been researched and developed. The seepage flow and behavior of phreatic line in reclaimed area was predominated by transient flow caused by tidal action. Also the soil-water characteristic relation is most important factor for transient flow analysis, therefore the research about the soil-water characteristic is strongly required. In this paper, laboratory tests (pressure cell, desiccator, and tensiometer test) and theoretical analysis were performed to investigate the soil-water characteristic such as air-entry value, metric suction, and residual water content. And the feasibility of prediction method for soil-water characteristic are presented by transient seepage analysis and comparison between analysis results and in-situ measured seepage flux in LNG TK-00 storage tank. Based on the result of laboratory and theoretical analysis, Fredlund and Xing's method provide to work out well for reclaimed ground soils. Also, the transient analysis result is more reasonable and effective for design of deep excavation work in coastal and reclaimed ground.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.12
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• pp.1327-1336
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• 2012

In this paper, the dual-faced monopole antenna, which is arranged by numerous rectangular ring patches in sequence for the multi-bands is proposed. The ring type structure of the patch can be increased the bandwidth. Therefore the bandwidth and beam width are improved by using multiple arrayed patches. When the ring type patches are inserted serially, the resonance frequencies are occurred by the current flow from the first ring patch. It is possible because the gap between the patches is very narrow. In addition, if the patches are composed on the same plane as the feed-line, fabrication could be very difficult because the gap between the patches is extremely narrow. The thickness and permittivity of the antenna, moreover, are very important parameters because both sides of the substrate are used. We finally found the optimal thickness and permittivity to generate the coupling effect by simulation. All patches are consisted of 4-steps which the patch size was decreased 85 % by each step. In conclusion, the resonant frequency bands are 1.75~2.6 GHz(850 MHz), 3.24~3.46 GHz(220 MHz), 3.8~4.0 GHz(200 MHz), and 4.4~4.9 GHz(500 MHz).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.2
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• pp.821-828
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• 2011

This paper developed the algorithm for improving the performance the auto pilot in the autonomous vehicle system consisting of the Track keeping control, the Automatic steering, and the Automatic mooring control. The automatic steering is the control device that could save the voyage distance and cost of fuel by reducing the unnecessary burden of driving due to the continuous artificial navigation, and avoiding the route deviation. During the step of the ship autonomic navigation control, since the wind power or the tidal force could make the ship deviate from the fixed course, the automatic steering calculates the difference between actual sailing line and the set course to keep the ship sailing in the vicinity of intended course. first, we could get the transfer function for the modeling of ship according to the Nomoto model. Considering the maneuverability, we propose it as linear model with only 4 degree of freedoms to present the heading angle response to the input of rudder angle. In this paper, the model of ship is derived from the simplified Nomoto model. Since the proposed model considers the maximum angle and rudder rate of the ship auto pilot and also designs the Fuzzy controller based on existing PID controller, the performance of the steering machine is well improved.