• 한국통신학회논문지
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• 제22권5호
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• pp.974-980
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• 1997

The 23GHz 1-state LNA was designed by using MPIE numerical analysis and conventional design EEsof softwares. The circuit was designed using conventional tools but analyzed and modified by using numerical MPIE tools. he matching sections was designed with parallel coupled filter-type, which gives impedance matching and DC blocking and has small discontinuities. THe FET chip is directly attached to the graound metal. The designed LNA gives 5.8dB gain and 2.5dB noise figure withoug considering the loss and impedance shift of connectors that degenerate the gain and noise figure considerably. this results gives very promising characteristics for our design process and matching schemes and fabrication technologies.

• 대한기계학회논문집B
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• 제30권5호
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• pp.422-429
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• 2006

Resolved simulations are presented fur gravity current flows aiming at studying their spreading rate. The simulations are performed for two extreme configurations such as planar and cylindrical and for 3 different Grashof numbers: $10^5,\;1{\times}10^6\;and\;10^7$. Varying the size of the heavy fluid release, the study is performed for several phases of spreading, namely acceleration, slumping and inertial phases. For the simulations, efficient spectral multi-domain code is used. From the simulations results it is concluded that 2-D results predicts well the mean front velocity during the slumping phase, but fails to predict it during the inertial phase of spreading. It is also observed that the vortex dynamics of the flow is not reproduced well by the 2-D simulation.

• 대한토목학회논문집
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• 제28권1B호
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• pp.115-123
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• 2008

본 연구에서는 파 잠제 해빈의 상호간섭에 의한 파동장 및 흐름장의 변화를 검토하기 위하여, 2기의 잠제와 모래해빈을 설치한 경우를 대상으로 허와 이(2007)에 의해 개발된 모델(LES-WASS-3D)을 이용하여 잠제 주변의 3차원적 흐름특성과 파고분포에 대해 고찰하였다. 그 결과, 잠제단부를 중심으로 회전하는 순환류를 확인할 수 있었으며, 여러 단면의 평균류 및 평균와도를 검토함으로서 잠제주변의 3차원 흐름특성을 고찰하였다. 아울러 잠제 천단상의 쇄파점분포, 잠제주변의 파고분포 및 wave set-up에 대해서도 논의하였다.

• 응용통계연구
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• 제4권2호
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• pp.171-178
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• 1991

고정된 접목점을 갖는 다항 스플라인 회귀모형에 대한 D-최적실험 계획의 성질들이 연구되 었다. 또한 정규화된 B-스플라인을 이용하여 몇가지 경우에 대한 D-최적실험계획을 이론적 으로 구하였다. Kiefer-Wolfowitz 동치정리에 의하여 몇가지 모형에 대한 D-최적실험 계획 이 수리적인 방법에 의해 근사적으로 구하여 졌다.

• 한국전자파학회논문지
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• 제11권3호
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• pp.429-436
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• 2000

본 논문에서는 부분 대역 잡음 재밍이 존재하는 직교성 비동기 FH-BFSK 통신시스댐의 성능을 분석하였다. 그리고 전체 확산대역에서의 재밍대역 비융인 $\rho$값의 변화할 때 처리이득에 따른 비트에러확률을 분석하였다. 분석결과를 수치해석과 SPW를 이용한 컴퓨터 시율레이션을 수행하여 성능을 평가하였다. JSR이 lOdB일 때 시스템의 SNR이 lOdB이하라면 높은 처리이득에서도 error floor가 발생하여 요구하는 성능을 실현할 수 없었으며 SNR이 12 dB이상에서는 $\rho$의 변화에 따라 요구하는 에러확률를 만족하는 처리이득이 달라짐을 알 수 있다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 A
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• pp.518-520
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• 2004

In these days, there is a demand to develop fault current limiters(FCLs) to reduce excessive fault current and protect electrical equipments which are installed in the transmission and distribution power systems. We considered the resistive superconducting FCLs among the various kinds of FCLs. In this study, in order to develop the resistive superconducting FCL of 6.6kV 200A $3\phi$, we designed the new mask pattern for etching YBCO films by means of numerical analysis method, current limiting experiments and visualization of bubbles in films and investigated dielectric performance of the designed mask by using elecrtostatic numerical analysis method and breakdown experiments. We etched YBCO films by using the newly designed mask, connected the etched films in series and in parallel, and designed the 6.6kV resistive SFCL and then we observed the current limiting characteristics of the SFCL.

• 대한기계학회논문집B
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• 제29권1호
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• pp.123-130
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• 2005

A digital in-line holographic particle image velocimetry (HPIV) which can be applied to measure three-dimensional velocity fields of turbulent flows was developed. There are three different implementation methods of HPIV: traditional film-based HPIV, intermediate HPIV and digital HPIV. The traditional film-based HPIV and intermediate HPIV method is rather troublesome to do experiments and takes long calculation time, compared with the digital HPIV, Configuration of the digital in-line HPIV is simple and the data processing routine is similar to conventional 2D PIV methods. The digital HPIV velocity field measurement consists of four steps: recording, numerical reconstruction, particle extraction and velocity extraction. In the velocity extraction process, we improved PTV algorithm to extract the displacement of particle each placed in 3D space. The developed digital in-line HPIV system was applied to a vertical jet flow. The 3D velocity vectors measured by the digital HPIV method in the near field are in a good agreement with 2D PIV results.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2004년도 추계학술발표회 발표논문집
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• pp.305-306
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• 2004

• 한국의류산업학회지
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• 제15권6호
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• pp.963-970
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• 2013

The purpose of this study was to develop torso pattern of underweight female in their 20s~30s by using Clo 3D virtual garment simulation system. The results were as follows; first, as a result of analyzing torso somatotype, underweight women showed lower average than average values of whole women in their twenties and thirties in the items such as length, width, circumference, thickness except for height. Second, by using 3D virtual garment simulation, new torso pattern considered underweight female was development. The basic numerical formula were as follows ; bust girth B/2+3.5, armhole depth B/4+0.5, front waist girth W/4+0.5+0.7, back waist girth W/4+0.5-0.7, front hip girth H/4+1+0.5, back hip girth H/4+1-0.5, chest width B/6+3.1, back width B/6+4.5, neck width B/12+0.2 and neck depth B/12+1.7. Third, by reducing hollowed amount of front, back, and side line, and hollowed amount of back center line, the reduced quantity was included to darts amount. Number of dart was adjusted to two pieces so that darts amount was equally distributed to two darts. Forth, according to the results of the new torso pattern's appearance evaluation, it estimated more highly than existing pattern in silhouette and ease amount, confirming that new torso pattern was appropriate for the underweight women. This study is expected to serve as one of important basic data for ensuing studies that may utilize 3D virtual garment simulation system with 2D patterns, and also for future 3D pattern production program development.

• 대한기계학회논문집B
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• 제37권11호
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• pp.1037-1046
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• 2013

본 연구에서는 측정기준 수립을 위해 실험된 결과를 통계적으로 분석하였다. 측정오차에 미치는 영향력의 크기는 회선 수, 센서의 설치각도 및 직관거리가 심한 영향을 미치며 레이놀즈수가 다음으로 영향을 준다. 2중 곡관하류의 유동패턴을 이해하기 위하여 3D 수치해석을 수행하였다. 수치해석 결과는 1회선에서 센서의 설치각도 $0^{\circ}$와 $45^{\circ}$, $135^{\circ}$의 L/D=3과 5의 경우가 실험과 잘 일치하는 것으로 나타났다. 결과적으로 레이놀즈수 700,000~1,400,000일 때, 1회선 초음파유량계는 센서의 위치를 L/D=3의 $45^{\circ}$에 설치함으로서 오차를 줄일 수 있다.