• 대한인간공학회지
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• 제27권3호
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• pp.7-14
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• 2008

In this study, four alternatives for the arrangement of Korean alphabets on computer keyboards are developed and analyzed to find the better design than the KS(Korean Standard) keyboard. Among the developed four modified models MOD 1 to MOD4, we suggest MOD3 as the best design which incorporates the keys usage frequencies and the compatibility of present standard.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 하계종합학술대회 논문집(1)
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• pp.383-386
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• 2002

The goal of this study is to realize the PBG lowpass filter using novel PBG structure modification both upper layer and ground layer. It has been designed three aperture slots of ground layer for PBG structure which the center slot shape of ground is two type, rectangular and dumbbell. This PBG LPF llas the character of the broader stopband and smaller size than typical LPF. The measurement results have matched the simulated ones. It has the cutoff frequency of each 4.4650Hz and 3.520Hz and at least -2OdB of the signal suppression at the stopband.

• Structural Engineering and Mechanics
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• 제62권1호
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• pp.113-123
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• 2017

The bi-material elastic system consisting of the circular hollow cylinder and the infinite elastic medium surrounding this cylinder is considered and it is assumed that on the inner free face of the cylinder a point-located axisymmetric time harmonic force, with respect to the cylinder's axis and which is uniformly distributed in the circumferential direction, acts. The shear-spring type imperfect contact conditions on the interface between the constituents are satisfied. The mathematical formulation of the problem is made within the scope of the exact equations of linear elastodynamics. The focus is on the frequency-response of the interface normal and shear stresses and the influence of the problem parameters, such as the ratio of modulus of elasticity, the ratio of the cylinder thickness to the cylinder radius, and the shear-spring type parameter which characterizes the degree of the contact imperfectness, on these responses. Corresponding numerical results are presented and discussed. In particular, it is established that the character of the influence of the contact imperfection on the frequency response of the interface stresses depends on the values of the vibration frequency of the external forces.

• 한국가스학회지
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• 제13권1호
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• pp.9-13
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• 2009

가스히터의 가동으로 인하여 발생하는 소음 및 진동의 주 원인은 연소음(combustion roar)과 연소진동음(combustion oscillation)이다. 연소음(combustion roar)의 특징은 음압이 넓은 주파수대에 걸쳐 있고, 크기도 비교적 일정 하다. 반면 연소진동음(combustion oscillation)은 연소실내 기체의 고유진동수에 대하여 버너계가 Positive Feedback을 일으켜 공진할 때 발생되는 소음 및 진동이다. 따라서 소음 및 진동을 해결 할 수 있는 방법은, 공진을 피하는 것이다. 첫 번째, 버너에서 연료와 공기량의 비율을 조절하여 진동수를 변화시키거나, 연소실내에서의 연료와 공기의 혼합속도를 변화시키는 방법이 있다. 두 번째, 연소실의 길이나 이코노마이저(Economizer)의 형상을 바꾸어 고유진동수를 변경시키는 방법이 있다. 본 논문에서는 이코노마이저(Economizer)를 변경하여 공명을 회피하였다.

• 대한전자공학회논문지TC
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• 제47권2호
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• pp.62-66
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• 2010

본 논문은 높은 Q 특성을 갖는 이중 H자 형태의 메타 전자파구조의 공진기를 적용한 발진기를 제안하였다. 제안된 발진기는 고성능의 주파수합성부에 적용하기 위한 것으로 저위상잡음 및 높은 출력 전력을 요구한다. 특히 이중 H자 형태의 메타 전자파구조(DHM)는 전기장의 커플링을 강하게 하여 발진 주파수에서 높은 Q 값을 갖도록 설계되었다. 이러한 특성을 통해 우수한 위상잡음 특성을 얻을 수 있다. 이중 H자 형태의 메타 전자파구조를 이용한 발진기는 레이더 시스템의 주파수 합성부에 적용하기 위한 X 대역 내 발진을 형성하였으며 출력 전력은 4.33 dBm, 위상잡음은 100 kHz 옵셋에서 -108 dBc를 얻을 수 있었다.

• 가정과삶의질연구
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• 제6권1호
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• pp.1-25
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• 1988

The purpose of this study was to classify the communication styles of the husbands and wives in Korea. The instrument of this study was questionnaire which was made through the three times' pre-research by the researcher. In the pre-research, husbands and wives were asked what were the communication styles in their daily life. Among the gathered data 55 items were chosen by the frequency of the communication styles. The subjects were 240 husbands and 264 wives who lives in Seoul. In this study the following questions were examined. 1) What are the communication styles of the husbands? 2) What are the communication styles of the wives? The data were analyzed by the method described below with SAS and SPSS computer programs. 1) To find out general character of the subjects, frequency distribution and frequency percentage should be computed. 2) To analyze items of the scale, mean standard deviation, and relative frequency distribution of the respective items should be computed. 3) To extract factor of the respective group, the procedure of factor analysis should be applied. 4) To verify the reliability of the respective factor, Cronakch's α should be computed. 5) To notice the differences in background variables, the analysis variance should be computed. The conclusions derived from the findings were as follows: 1) The communication styles of the husbands group were categorized into authoritarian style, contactful style, sincere style, speculative, speculative style, other-oriented style. 2) The communication styles of th wives group were categorized into authoritarian style. sincere style, other-oriented style, sacrifice style, speculative style.

• 디지털콘텐츠학회 논문지
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• 제8권3호
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• pp.355-363
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• 2007

학습자의 성격유형에 따른 학습 선호도는 학습 성취의 주요 인자 중의 하나이다. 따라서 학습자는 자신의 성격 유형과 다른 콘텐츠로 학습을 하게 되면 스트레스가 증가하여 혈압이나 심박동수에 변화가 나타나게 된다. 본 연구에서는 학습자의 비선호도를 측정하기 위해서 스트레스 량 측정에 사용되는 주파수 영역 정보를 이용하였다. 먼저, 13명의 유치원 아동들을 MBTI 성격유형의 감각/직관의 두 유형으로 파악하고 이들에게 동일한 학습 콘텐츠를 10분간 제시한 후, 이를 학습하는 동안 측정된 심전도 신호를 심박변동신호(heart rate variability: HRV) 신호로 재구성하였다. 이 HRV 신호를 주파수로 변환한 후에 저주파(LF: low frequency), 중간 주파(MF: middle frequency), 그리고 고주파(HF: high frequency) 영역으로 분할하고, 각 주파수 영역비를 비교하여 학습자의 성격 유형에 따라 학습 콘텐츠에 대한 선호도가 달라지는 지 여부를 알아보았다. 실험 결과는 아동들은 자신의 성격 유형에 따라 각기 다른 학습 콘텐츠를 선호한다는 사실을 보여준다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 학술대회 논문집 전문대학교육위원
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• pp.187-190
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• 2002

In contrast to conventional electromagnetic motor, USM(Ultrasonic Motor), as piezoelectric ceramic applying ultrasonic mechanical vibration and as frictional-movement type motor, get rotational torque by elastic friction between stator and rotator, The USM, which is small motor without iron cores and coil as a simple structure, has little load weight, has character of high torque at low speed, and can apply a direct drive type without deceleration gear as low speed type. A response of USM from control input is satisfactory, and also generates much torque in low speed driving, and holding torque is much without supplying power. In this study, I designed and made Ultrasonic motor-digital multi controller(USM- DMC) using FPGA chip, A54SX72A made in Actel Corporation. By the minute, USM-DMC can control frequency, duty ratio, and phase difference of USM by llbit digital input from Pc. Therefore, when we use this controller, we can apply to typical parameter, frequency, phase difference, and voltage parameter, to control as well as we can do mixing control like phase-frequency, phase-voltage, frequency-voltage, frequency-phase-voltage, What is more, the strongest point is that it can trace frequency based on optimized frequency because we can input optimized resonant frequency while in motoring.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1990년도 추계학술대회 논문집 학회본부
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• pp.263-266
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• 1990

In order to high-respone and high-reliability of devices, it depended upon how we can increase the high-frequency of the Inverter, UPS and it's application. but using high-frequency of self turn-off devices, it is important to reduce switching device loss and spike voltage of turn off. This paper proposed new methode about computer simulation of device loss also experimental results with switching device characteristic are presented.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.611-613
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• 2004

This paper is concerned with the simulation and determination of the input voltage and frequency for the optimal efficiency operation of induction motors. In general, induction motors have a specific character that operation efficiency is dropped sharply at the light roads condition. Consequently, if the induction motor is controlled by high efficiency using the VVVF(variable voltage variable frequency) control methods at optimal values, the entire system can obtain the substantial energy savings from the efficiency improvement in induction motors. In this paper, optimal slip is derived from the modeling of an induction motor and the optimal hybrid-control method is suggested by the simulation of the proposed algorithm for a 3-phase induction motor.