• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.5
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• pp.1077-1083
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• 2000

With rising demand of Internet Service, the existing communication for users (aced the restricted capability and speed, and also failed to satisfy consumer's desire for providing service-quality to them. It can be accomplished the broad-band on subscribe-line to offer various multimedia service to subscriber. But it takes a lot of times and costs. Consequently, it stands out the most economic subscribe-line for acheving a broadband scheme that new transmission technology can be realized the high-speed data communication as the present telephone-line and telephone by the general public of FTTH(Fiber To The Home). As using the pseudo line, this paper have the result that the mesured speed was improved by connecting a variable resistor on the line.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.311-311
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• 2010

본 논문은 직류전원에 펄스주파수를 인가함으로써 AZO 박막이 미치는 영향에 대해 알아보기 위해 기존과는 다른 형태인 원통형의 회전(Cylindrical rotatable)하는 방식을 가진 DC magnetron sputter를 이용하였다. 인가되는 전력과 압력, 온도 그리고 거리는 각각 고정하였고 펄스 주파수 가변을 통해 박막의 전기적, 광학적, 구조적 그리고 SEM등의 다양한 특성에 대해 확인하였다. 박막의 광학적 특성인 투과도를 알아보기 위해 UV-Vis를 이용하여 측정하였고 가변 범위에 관계없이 550 nm의 파장 길이에서 약 90%의 투과도를 보였다. 그리고 펄스주파수가 증가할수록 XRD의 Intensity는 오히려 감소되는 경향을 보였고, 홀 측정을 통해 비저항의 증가와 전자농도 증가, 감소된 홀 이동도를 통해 증가된 펄스 주파수가 박막의 구조적, 전기적 특성이 얼마나 많은 영향을 끼치는지 또한 알 수 있었다. 그리고 펄스주파수는 면저항과 홀 이동도의 감소 요인이며 이것은 XRD의 결과로 확인하였다. 펄스주파수가 향후 박막 태양전지 및 TFT와 NVM 등의 소자를 적용하는데 있어 중요한 요소 중의 하나로 판단할 수 있다.

• Proceedings of the Korea Information Processing Society Conference
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• 2022.11a
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• pp.997-999
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• 2022

아기의 심장 박동 소리를 듣지 못하는 청각 장애 부모를 위한 태아 초음파 심장박동 촉각 변환 시스템을 개발하고자 하였다. 본 시스템은 아기의 심장박동 소리를 USB 마이크를 이용하여 소릿값을 입력받아 이에 대응하는 값을 진동 모터의 진동 출력 세기와 LED 밝기의 세기로 출력시키도록 하였다. 아기의 심장박동 느낌을 진동으로 표현해 내기 위해 진동의 샘플링 주기를 구체적인 수치로 조절하였고 산모에 따라 진동의 세기와 주변 잡음 제거를 할 수 있도록 조절하는 가변저항 2개를 연결하였다. 그 결과 태아 초음파 심장박동 촉각 변환 시스템을 성공적으로 개발하였으며 장치 체험자들로부터 총 평균 4.63점으로 높은 만족도를 얻었다. 개발 제품은 청각장애 산모들의 모성애를 충족시키고 아기의 심장박동을 느낌으로써 아기의 존재를 느낄 수 있을 것이며, 산부인과의 초음파 영상진단의 확장 신기술로 활용할 수 있을 것으로 기대된다.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.3 no.1
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• pp.7-13
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• 2009

Recently, the interest on walking assistances in order to assist aged people has increased due to the increase of the aged. However, most walking aid systems have a weakness for a slope because they don't have power. So, they have a weak point which makes users difficult to move when they are weak in the legs. That is why the interest on walking assistances with power has increased. The use of the walking aid systems should be easy because most users are old people. Thus, we produce module to grasp walking intent of users by using various sensors such as potentiometer, FSR(Force Sensing Resistance) Sensor and Stretch Sensor and calculate the response time to the module. Firstly, the response time of handlebar which is a kind of potentiometer is 420ms and Resilience of it is 140ms. Secondly, the response time of handlebar which use FSR Sensor is 320ms and Resilience of it is 220ms. Finally, the response time of the Stretch Sensor is 160ms and Resilience of it is 140ms. The performance of Stretch Sensor is the best among the three kind of sensors.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.9
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• pp.813-819
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• 2011

In this paper, a new design method of a tunable oscillator using a suspended-stripline resonator is presented. The negative resistance of an FET mounted on microstrip line(MSL) is combined with a high Q suspended-stripline(SSL) resonator to produce a tunable oscillator with good phase noise. The new MSL-SSL transition facilitates the easy connection between the MSL-based circuits and the SSL module. The proposed oscillator is also frequency-tunable using a tuner located on the top of the SSL housing. The measured phase noise of the implemented oscillator at 3.37 GHz is -108.03 dBc@100 kHz and -135.09 dBc@1 MHz with 50 MHz of frequency tuning.

• Journal of Korean Society of Transportation
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• v.25 no.4
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• pp.99-108
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• 2007

This paper presents an elastic demand stochastic user equilibrium traffic assignment that could not be easily tackled. The elastic demand coupled with a travel performance function is known to converge to a supply-demand equilibrium, where a stochastic user equilibrium (SUE) is obtained. SUE is the state in which all equivalent path costs are equal, and thus no user can reduce his perceived travel cost. The elastic demand SUE traffic assignment can be formulated based on a dynamic system, which is a means of describing how one state develops into another state over the course of time. Traditionally it has been used for control engineering, but it is also useful for transportation problems in that it can describe time-variant traffic movements. Through the Lyapunov Function Theorem, the author proves that the model has a stable solution and confirms it with a numerical example.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.6
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• pp.100-108
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• 2008

The transient ground impedance depending on configuration, size, and material of grounding electrodes as well as the shapes of impulse currents, has a significant affect on the performance of the grounding system. This paper presents experimental results in regard to the analysis method of transient ground impedance using the lightning impulse and variable frequency currents. Also a new estimation method to replace the effective surge impedance for transient ground impedance was proposed. The ground electrodes used in this experiment are virtual ground electrodes including both resistance and inductance components, carbon ground electrode with 1[m] length, copper electrode with 9[m] length and counterpoise with 40[m] length. Ground impedances using the proposed method were measured respectively. Comparing with the ground impedance using variable frequency current the conventional ground impedance($Z_1$) calculated from the peak values of impulse voltage and impulse current is observed more correct method for evaluating the performance of ground electrode than the effective surge impedance.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.10
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• pp.1409-1415
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• 2021

The Gysel divider has the advantage of easily setting the resistor in the circuit. If the line impedance in the Gysel divider is set differently, the input signal can be distributed to the two output ports at various distribution ratios. This paper proposes the Gysel divider that can change the power distribution to 1:3 or 3:1 by changing the line impedance. The impedance change of the line can be implemented by placing a floating copper plate on the bottom of the microstrip-line. When the floating copper plate and the ground plane are connected, the line operates as the microstrip-line, and when the floating copper plate and the ground plane are disconnected, the line operates as the coplanar-line. The proposed Gysel divider was fabricated at the center frequency of 1.5GHz. The fabricated 3:1 Gysel divider has a stable value S₁₁ of below -17dB, S₂₁/S₃₁ of 4.8±0.2dB, S₂₁(to high output port) of -1.39±0.12dB and S₃₁(to low output port) of -6.15±0.08dB over 1.3~1.7GHz.

• Geophysics and Geophysical Exploration
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• v.16 no.4
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• pp.257-267
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• 2013

3-D ore modeling was performed to understand the configuration of ore bodies by integrated analysis of borehole and geophysical data in iron-mine area. Five representative indices of rocks were designated, which were obtained from geological survey and borehole. The five indices of rocks were geostatistically simulated by Sequential Indicator Simulation method to delineate boundary of the ore bodies. And Ordinary Kriging and Sequential Gaussian Simulation was applied to make secondary information using resistivity data from magnetotellurics and DC resistivity survey, and this information was used for simple kriging with local varying means, one of integrated kriging techniques. From the correlation analysis between each properties, it was found that high grade of ore is characterized by increased density, whereas the electrical resistivity decreases. With the integrated results of geophysical and borehole data, it was also found that the real configuration of ore body was similar to the modeled result and information about ore grade in 3-D space was obtained.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.335-336
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• 2009

저가격 고효율 실리콘 태양전지를 구현하기 위하여 핵심적으로 적용되는 공정인 SOD(Spin on Doping) 확산공정 최적화에 관하여 연구하였다. n-type 도핑 물질로는 인(P509)을 사용하였으며, Spinning 속도와 Spinning 시간을 각 3000 rpm, 30 초로 고정하고 급속 열처리로에서 확산 온도와 확산 시간을 $800\;^{\circ}C\;{\sim}\;950\;^{\circ}C$, 2 분에서 20 분까지 가변하며 확산공정을 실시하였다. 4-Point Probe 장비로 에미터 표면 저항을 측정한 결과 확산 온도 $850\;^{\circ}C$에서 5분간 열처리 하여 확산 공정을 하였을 때 저가의 고효율 실리콘 태양전지를 구현하는데 적용 하기위한 $30\;{\sim}\;50\;{\Omega}$-sq의 에미터 표면 저항을 만족 시키는 $36\;{\Omega}$-sq의 값을 얻을 수 있었다.