• Korean Journal of Applied Biomechanics
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• v.33 no.4
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• pp.175-184
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• 2023

Objective: The purpose of this study is to investigate the effects of human motion and javelin kinematics during the energy transfer in javelin throwing on records, and to provide evidence-based training insights for athletes and coaches to enhance records. Method: Three javelin throw athletes (age: 22.67 ± 0.58 years, height: 178.33 ± 7.37 cm, weight: 83.67 ± 1.15 kg) were recruited for this study. Each athlete attempted ten maximum record trials, and the kinematic data from each performance were analyzed to determine their influence on the records. The Theia3d Markerless system was used for motion analysis. Results: Key factors were modeled and identified at each moment. In E1, main variables were COM Y (𝛽 8.162, p<.05) and COM velocity Z (𝛽 -72.489, p<.05); in E2, COM X (𝛽 -17.604, p<.05); in E3, COM X (𝛽 -18.606, p<.05), COM velocity Y (𝛽 38.694, p<.05), and COM velocity X (𝛽 66.323, p<.05). For the javelin throw dynamics in E3, key determinants were Attitude angle and Javelin velocity in the Y-axis. Conclusion: The study reveals that controlled vertical movement, center of mass management during braking, and enhanced pelvic rotation significantly improve javelin throw performance. These kinematic strategies are critical for record enhancement in javelin throwing.

• Proceedings of the SAREK Conference
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• 2006.11a
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• pp.64-64
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• 2006

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1991.04a
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• pp.96-102
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• 1991

절삭가공의 목적은 소재의 불필요한 부분을 chip으로 제거하여 소요의 형상 치수인 새로운 표면을 만들어 내는 것이다. 실제 가공에서 소요되는 동력을 보면 대부분은 chip을 만들어 내는데 소비되기 때문에 chip의 특성은 절삭가공에 있어서 극히 중요한 인자가 되는 것이다. 본 연구에서는 많이 사용되고 있는 throw away 공구에서의 칩 브레이커의 성능을 향상시키기 위하여 실험을 통하여 기존에 사용되고 있는 공구들의 성능을 평가하고 문제점을 제시한다.

• IEIE Transactions on Smart Processing and Computing
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• v.5 no.3
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• pp.164-168
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• 2016

A low insertion-loss, high-isolation switch based on single pole double throw (SPDT) for a 2.4GHz Bluetooth low-energy transceiver is presented in this paper. In order to increase isolation, the body floating technique is implemented. Based on characteristics whereby the ratio of the sizes of the shunt and the series transistors significantly affect the performance of the switches, the device sizes are optimized. A simple matching network is also designed to enhance the insertion loss. Thus, the SPDT switch has high isolation and low insertion loss without increasing the complexity of the circuit. The proposed SPDT is designed and simulated in a complementary metal-oxide semiconductor 65nm process. The switch has a $530{\mu}m{\times}270{\mu}m$ area and achieves 0.9dB, 1.78dB insertion loss and 40dB, 41dB isolation of transmission, reception modes, respectively.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.4
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• pp.155-159
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• 2004

This paper describes the design and the simulation of a single pole double throw(SPDT) FET switch for wireless LAN(IEEE802.11a ＆ IEEE802.11b) applications using drain impedance transformation network with Microstrip transmission line. At the receiving path insertion losses were from 0.8(㏈) to 1.462(㏈) between 2(㎓) and 4(㎓), from l.26(㏈) to 2.3(㏈) between 4.7(㎓) and 6.7(㎓) and the isolations were under 30(㏈) between 2(㎓) and 6.7(㎓). At the transmitting path insertion loss were from 1.18(㏈) to 2.87(㏈) between 2(㎓) and 4(㎓) from 0.625(㏈) to 1.2(㏈) between 4.7(㎓) and 6.7(㎓) and the isolations were under 30(㏈) between 2(㎓) and 6.7(㎓).

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.10 s.101
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• pp.1003-1009
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• 2005

In this paper, small-size high-power single pole double throw(SPDT) switch with defected pound structure(DGS) is presented for wireless broadband internet application. To reduce the circuit size using slow-wave characteristic, the DGS is applied to ${\lambda}/4$ transmission line of the switch and the measured results are compared with them of conventional switch. To secure high degree of isolation, the switch with the DGS is composed of shunt-connected PIN diodes and shows insertion loss of 0.8 dB and isolation more than 50 dB at 2.3 GHz. The size of the switch is reduced about $50\%$ only with the DGS patterns while it has very similar performance to the conventional shunt-type switch.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.9
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• pp.833-839
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• 2011

This paper has suggested a technique for measuring VSWR at 1.8 GHz band for various modulated signals. By using directional coupler the power of incident and reflected wave is measured, and in order to minimize the size and cost of the measuring circuit, a SPDT(Single Pole Double Throw) switch is adopted to realize the circuit with just one detector and one A/D(Analog to Digital) converter. MCU(Micro Control Unit) is used to calculate the voltage reflection coefficient and VSWR, and the measured VSWR error has improved by approximately 0.2 with applying a simple bubble sorting algorithm to reduce the measurement error, the MCU process time and load.

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.958-964
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• 2001

It is difficult to apply a conventional selection guide for diffusers when the diffuser is installed in a perimeter zone, because the ADPI(Air Diffusion Performance Index) vs. T/L(Throw/Length) curve listed in conventional guide does not consider the perimetric heating load. The objective of this study is to evaluate the effect of the perimetric heating load on the ADPI and to propose a selection guide for proper diffuser when perimetric heating load exists. The velocity and temperature distributions and the ADPI value are obtained numerically with various heat load ratios and air flow rates. The ADPI values by numerical result were compared with existing experimental data to verify the method for evaluation of ADPI proposed in present study. In case of a high side wall diffuser, the ADPI decreased with increases of the flow rate on every heat load ratio of present study except 0.75. Also, the ADPI vs. T/L curves have been proposed for the heat load ratios of 0.25, 0.5, 0.75 to guarantee comport thermal environment when diffusers are installed in perimeter zone.

• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.4
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• pp.511-519
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• 2016

This paper proposes a CMOS 6-bit phase shifter with low RMS phase and amplitude errors for an X-band phased array antenna. The phase shifter combines a switched-path topology for coarse phase states and a switch-filter topology for fine phase states. The coarse phase shifter is composed of phase shifting elements, single-pole double-throw (SPDT), and double-pole double-throw (DPDT) switches. The fine phase shifter uses a switched LC filter. The phase coverage is $354.35^{\circ}$ with an LSB of $5.625^{\circ}$. The RMS phase error is < $6^{\circ}$ and the RMS amplitude error is < 0.45 dB at 8-12 GHz. The measured insertion loss is < 15 dB, and the return losses for input and output are > 13 dB at 8-12 GHz. The input P1dB of the phase shifter achieves > 11 dBm at 8-12 GHz. The current consumption is zero with a 1.2-V supply voltage. The chip size is $1.46{\times}0.83mm^2$, including pads.

• Explosives and Blasting
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• v.20 no.2
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• pp.7-19
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• 2002

The cut is placed high up in the section, the 1st sloping holes below the cut, and divided all the holes located below the 1st sloping holes into a certain area with longitudinal section, to lower pollution made from tunnel blasting. With the sequential blasting machine, after I first blasted holes around the cut holes by a pre-splitting method, blasted the cut area and the 1st sloping holes. The 1st and 2nd sloping holes divided areas are initiated gradually to free face upwards made by the cut. Especially, I pre-splinted contour holes previous blast the before sloping holes from the contours. The ground vibration from the earth surface just over the advance face decreased about 42.0% compare with the down blasting method under the condition of equal charge weight per delay. I controlled the crack and over break of the mother rock by pre-splitting contour holes before blast the first sloping holes from the contours. The peak values of noise and air blast by blasting decreased about 10dB more than the down blasting method. the noise and air blast diminished gradually as a round. The throw distance of the fly rock was decreased about 55%.