• Korean Journal of Acupuncture
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• 제27권2호
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• pp.141-157
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• 2010

Objectives : The aim of this study is to examine the effects of acupuncture at PC7(Daereung) on normal human EEG using power spectral analysis. Methods : EEG power spectrum exhibits site-specific and state-related differences in specific frequency bands. In this study, power spectrum was used as a measure of complexity. 30 subjects (16 males and 14 females; averaged age = 23.4 years) were engaged with thirty channel EEG study. Results : In $\alpha$(alpha) band, the power values at Fp1, Fp2, F7, F8 channels(p<0.05) during PC7 treatment were significantly decreased. But, the power values at Fz channel(p<0.05) during non-acupoint treatment was significantly decreased. In $\beta$(beta) band, the power values at Fp1, Fp2 channels(p<0.05) during PC7 treatment were significantly decreased. But, the power values at Fz channel(p<0.05) during non-acupoint treatment was significantly decreased and at F8, TCP2 channels(p<0.05) during non-acupoint treatment were increased. In $\theta$(theta) band, the power values at Fp1, Fp2, F7, F8 channels(p<0.05) during PC7 treatment were significantly decreased. But, the power values at Fz channel(p<0.05) during non-acupoint treatment was significantly decreased. In $\delta$(delta) band, the power values at Fp1, Fp2, F7, Fz, F8 channels (p<0.05) during PC7 treatment were significantly decreased. But, the power values at Fz channel (p<0.05) during non-acupoint treatment was significantly decreased. $\alpha/\beta$ values during PC7 treatment were decreased. $\beta/\theta$ values during PC7 treatment were decreased. Conclusion : These results suggest that acupuncture at PC7 induce the change on $\alpha$(alpha), $\beta$(beta), $\theta$ (theta), $\delta$(delta) wave values being decreased and and bothe $\alpha/\beta$ and $\beta/\theta$ values being decreased respectively. This is considered that acupuncture at PC7 affects the activity of cerebral cortex and endocrine system.

• 한국식생활문화학회지
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• 제4권1호
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• pp.59-69
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• 1989

As for the Japanese dietary style and dietary equipments, many are regarded, with the rice plant imported, as the influence of China and Korea, while traditional culture has recently changed in Japanese and Korean urban lives because of the increase of nuclear families and modernization of lives. Of 1,244 junior high school students of boys and girls in Tokyo and Seoul, we investigated the present situations of the employment of dining equipments October to November, 1987. The results obtained are as follows. More cases that each member of a family had his or her own dining equipment were found in Japan. The frequency of using chopsticks was high in both countries. Korean children, having no struggles, handled chopsticks better than Japanese children. As for the dishing-up of sidedishes, more than half of Japanese used their individual plates, while in Korean families they used whole dishes. As for the employment of dining equipments, Japanese people have established their own style because of the national character of delicacy and finicality. This kind of traditional habits were found much more in extended families than in nuclear families. In Korea, the traditional spirit and the broad-minded characteristics cherished in the continental circumstances were manifested in the employment of dining equipments and their strong national character will not easily accept the wave of modernization.

• 한국전자파학회지:전자파기술
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• 제6권1호
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• pp.37-47
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• 1995

본 논문에서는 기존의 마이크로스트립 안테나가 갖는 협대역 특성과 급전선의 기생방사로 인한 방사패턴의 열화를 개선할 수 있는 슬롯결합 적충 마이크로스트립 안테나의 특성을 해석하고, 중심주파수 l1.5GHz와 12. $\alpha$}Hz에서 독립적인 공진 특성을 갖는 두 패치와 급전 슬롯의 상호결합작용에 의한 이중공진현상으로 인하여 15-20%의 대역폭을 갖는 적충안테나를 설계 제작하여 1.9-2.2GHz의 광대역 특성을 지님을 실험적으로 확인 하였다. 이에 대한 해석은 산란해석방볍을 이용하여 슬롯결합 급전구조에 대한 정확한 해석 모델을 제시하고, 제시된 모델과 함께 스펙트럼 영역에서 Green 함수를 유도하고 Galerkin 방법에 의해 수치적 계산을 하는 Full wave 해석방볍을 적용하였다. 수치해석에 사용된 기저함수는 해의 수렴도, 정확도 및 계산시간을 비교하여 패치는 3 개의 EB 모드, 급전선은5개의 PWS 모드를 사용하였다.

• 한국전자파학회논문지
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• 제21권7호
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• pp.842-849
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• 2010

본 논문에서는 저궤도 위성용 TT&C 안테나로 사용하기 위한 광대역 원형 편파 턴스타일 안테나를 제안한다. 턴스타일 안테나는 신호를 자유 공간으로 방사하기 위한 다이폴 방사부와 원형 편파 발생을 위한 서로 90도 위상차를 가지는 두 신호를 공급하는 전력분배기부로 구성된다. 다이폴 방사부는 발사 및 우주 궤도의 극한 환경에서도 견딜 수 있는 견고한 구조로 고안을 하였으며, 전력분배기부는 광대역 특성을 가지면서 주파수에 대해 평탄한 90도 위상차를 공급할 수 있도록 설계하였다. 제안된 안테나는 저궤도 위성용 TT&C 상 하향 링크를 동시에 만족할 수 있는 광대역 특성을 가지며, 전천후 임무 수행이 가능한 넓은 빔 폭과 개선된 원형 편파 축비 특성을 보인다.

• Journal of electromagnetic engineering and science
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• 제18권2호
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• pp.117-128
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• 2018

In this paper, compact linear dual polarized series-fed $1{\times}2$ linear and $2{\times}2$ planar arrays antennas for airborne SAR applications are proposed. The proposed antenna design consists of a square radiating patch that is placed on top of the substrate, a quarter wave transformer and $50-{\Omega}$ matched transformer. Matching between a radiating patch and the $50-{\Omega}$ microstrip line is accomplished through a direct coupled-feed technique with the help of an impedance inverter (${\lambda}/4$ impedance transformer) placed at both horizontal and vertical planes, in the case of the $2{\times}2$ planar array. The overall size for the prototype-1 and prototype-2 fabricated antennas are $1.9305{\times}0.9652{\times}0.05106{{\lambda}_0}^3$ and $1.9305{\times}1.9305{\times}0.05106{{\lambda}_0}^3$, respectively. The fabricated structure has been tested, and the experimental results are similar to the simulated ones. The CST MWS simulated and vector network analyzer measured reflection coefficient ($S_{11}$) results were compared, and they indicate that the proposed antenna prototype-1 yields the impedance bandwidth >140 MHz (9.56-9.72 GHz) defined by $S_{11}$<-10 dB with 1.43%, and $S_{21}$<-25 dB in the case of prototype-2 (9.58-9.74 GHz, $S_{11}$< -10 dB) >140 MHz for all the individual ports. The surface currents and the E- and H-field distributions were studied for a better understanding of the polarization mechanism. The measured results of the proposed dual polarized antenna were in accordance with the simulated analysis and showed good performance of the S-parameters and radiation patterns (co-pol and cross-pol), gain, efficiency, front-to-back ratio, half-power beam width) at the resonant frequency. With these features and its compact size, the proposed antenna will be suitable for X-band airborne synthetic aperture radar applications.

• Smart Structures and Systems
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• 제4권6호
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• pp.727-740
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• 2008

A down hole vertical seismic array is a sequence of instruments installed at various depths in the earth to record the ground motion at multiple points during an earthquake. Numerous studies demonstrate the unique utility of vertical seismic arrays for studying in situ site response and soil behavior. Examples are given of analyses made at two sites to show the value of data from vertical seismic arrays. The sites examined are the Lotung, Taiwan SMART1 array and a new site installed at Jingliao, Taiwan. Details of the installation of the Jingliao array are given. ARX models are theoretically the correct process models for vertical wave propagation in the layered earth, and are used to linearly map deeper sensor input signals to shallower sensor output signals. An example of Event 16 at the Lotung array is given. This same data, when examined in detail with a Bayesian inference model, can also be explained by nonlinear filters yielding commonly accepted soil degradation curves. Results from applying an ARMAX model to data from the Jingliao vertical seismic array are presented. Estimates of inter-transducer soil increment resonant frequency, shear modulus, and damping ratio are presented. The shear modulus varied from 50 to 150 MPa, and damping ratio between 8% and 15%. A new hardware monitoring system - TerraScope - is an affordable 4-D down-hole seismic monitoring system based on independent, microprocessor-controlled sensor Pods. The Pods are nominally 50 mm in diameter, and about 120 mm long. An internal 16-bit micro-controller oversees all aspects of instrumentation, eight programmable gain amplifiers, and local signal storage.

• 한국통신학회논문지
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• 제24권9B호
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• pp.1668-1675
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• 1999

본 논문에서는 위성통신용 멀티플렉서에 사용 가능한 협대역 대역통과 여파기를 설계하기 위해 협대역 특성을 가지며 삽입 손실 및 소자의 크기를 최소화시킬 수 있는 고온 초전도체를 이용하여 hairpin-line 및 hybrid hairpin-line/parallel-coupled-line 여파기를 설계하고 실험을 통해 그 특성을 고찰하였다. Hairpin-line만으로 설계된 대역통과 여파기는 surface wave에 의한 spurious mode가 발생한다는 단점이 있지만 본 논문에서 제안된 hybrid hairpin-line/parallel-coupled-line 여파기를 사용하여 spurious mode를 줄일 수 있다. 동작 주파수가 14.25 GHz인 협대역 대역통과 여파기는 고온 초전도체를 이용하여 동일한 3극에서 일반금속 마이크로스트립 여파기보다 더 좋은 1%미만의 협대역과 3 dB이상 적은 삽입손실을 갖도록 하였으며 따라서 같은 성능을 보이고자 할 때 그 크기를 최소화시킬 수 있도록 설계하였다.

• 한국통신학회논문지
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• 제18권4호
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• pp.468-480
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• 1993

본 논문에서는 2개의 동일한 1-Port 형 공진기를 병렬로 근접배치시킨 이중모드 SAW 공진기의 설계를 위하여, 우선, 결합 모드이론에 의한 1-Port 형 공진기의 특성을 기초로 하여, 도파로 모델을 적용한 이중모드 SAW 공진기의 특성을 분석하였으며, 이를 이용해서 중심 주파수가 150.15MHz이고 대역폭이 80KHz인 2-Pole 및 4-Pole 협대역 필터를 설계.제작 하였다. 이중모드 SAW 필터를 설계변수를 달리하여 여러 번 제작.실험하여 실험치와 이론치를 비교함으로써, 제품 설계에 사용 가능한 실험적 설계 특성을 얻었으며, 이동통신기기에서 사용될 수 있는 헙대역 통과 필터를 구현하였다. DMS 공진기를 구성한 압전 기판으로는 높은 주파수에서도 온도변화에 의한 주파수 이동 및 물성의 변화가 적은 ST-cut quartz(수정)를 선택하였으며, 필터의 제작은 정확한 전극구조를 얻기 위하여 고해상도 사진 식각법과 전극의 수직식각특성이 우수한 이온반응 식각법(Reactive Ion Etching)을 적용하였다.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제50권12호
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• pp.639-647
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• 2001

We present an integrated optical microswitch, composed of silicon waveguides, gold-coaled silicon micromirrors, and electrostatic contact actuators, for applications to the optical signal transceivers. For a low switching voltage, we modify the conventional curled electrode microactuator into a electrostatic microactuator with touch-down beams. We fabricate the silicon waveguides and the electrostatically actuated micromirrors using the ICP etching process of SOI wafers. We observe the single mode wave propagation through the silicon waveguide with the measured micromirror loss of $4.18\pm0.25dB$. We analyze major source of the micromirror loss, thereby presenting guidelines for low-loss micromirror designs. From the fabricated microswitch, we measure the switching voltage of 31.74V at the resonant frequency of 6.89kHz. Compared to the conventional microactuator, the present contact microactuator achieves 77.4% reduction of the switching voltage. We also discuss a feasible method to reduce the switching voltage to 10V level by using the electrode insulation layers having the residual stress less than 30MPa.

• 한국항공우주학회지
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• 제48권1호
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• pp.63-72
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• 2020

본 연구에서는 위성용 전장품 보드의 성능 요구조건과 설계 복잡도가 높아지면서 증가되는 노이즈 문제를 최소화하기 위해 전원 건전성(Power Integrity) 및 신호 건전성(Signal Integrity)의 설계 분석이 수행되었고 이를 통해 적용된 설계 개선 내용을 기술하였다. 전원 건전성은 정전류 전압강하(DC IR drop) 해석을 통해 정적 전원의 특성을 분석하였고, 각 전원의 임피던스 해석을 통해 동적 전원의 특성을 분석하여 각 분석 결과를 이용한 설계 개선 방안들이 적용되었다. 신호 건전성 측면에서는 주요 데이터버스 신호에 대한 시간영역 파형 분석과 PCB(Printed Circuit Board) 설계 수정을 통해 노이즈가 개선된 결과를 확인하였다. 또한 설계된 PCB 보드의 전원 층에 대한 공진모드를 분석하여 발생된 공진 영역들에 완화 조치를 적용하였고 조치결과를 시뮬레이션을 통해 확인하였다. 최종적으로 분석을 통해 설계 개선이 적용된 유닛에 대해 수정 전과 후의 EMC(Electro Magnetic Compatibility) RE(Radiated Emission) 노이즈 측정결과를 비교함으로써 방사성 노이즈가 감소되었음을 확인하였다.