• 전자공학회논문지B
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• 제30B권5호
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• pp.103-108
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• 1993

An image can be largely corrupted by the ambient illuminant, so that the image enhancement to restory natural color without respect to the ambient illuminant is needed. It this paper, a new color image enhancement technique based on color constancy is proposed. To enhance the image quality, higher volues of contrast and saturation are preferred, but their excessive values make an image unnatural. Since the color constancy processing preserves only hue, while reducing the dynamic range of lightness and saturation,the technique is needed in order to compensate this phenomenon. The proposed method transforms and increases lightness and saturation simultaneously to avoid the complexity in the related transformation by analyzing the relationship between the RGB and modified IHS coordinate system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.1064-1065
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• 2015

단상 계통 연계형 전력 변환기에서 계통과 연계하기 위해서는 계통의 위상 정보를 정확히 측정하여 전력 변환기의 출력 주파수와 위상이 동일한 상태로 전류가 공급 되도록 해야 한다. 본 논문에서는 단상 d-q 좌표 변환 기법을 통한 위상 동기화 기법을 적용하여 왜곡된 계통전압이 d축 전압에 야기 되는 에러 성분을 최소화 하는 보상 기법을 제안한다. 제안된 기법은 동기 d축 전압을 일정한 주기로 적분하여 에러 성분을 최소화 한 후, PI제어를 통해 d축 전압을 0으로 수렴하게 하는 기법이다. 제안된 기법은 추가적인 하드웨어를 요구하지 않는다. 본 논문의 타당성을 검증하기 위해 3[kW]급 단상 계통 연계형 전력변환기 시작품을 제작하고 실험을 통해 증명하였다.

• 한국전산유체공학회지
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• 제5권1호
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• pp.27-32
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• 2000

This study investigates the problem of phase change from liquid to solid in the inviscid stagnation flow. The instantaneous location of the solid-liquid interface is fixed for all times by a coordinate transformation. Finite difference method is used to obtain the solution of the unsteady problem, and the growth rate of solid and the transient heat transfer from the surfaces of solid are investigated. The transient solution is dependent on the three dimensionless parameters, but the final steady state is determined by only one parameter of temperature ratio/conductivity ratio. It is observed that the instantaneous heat flux at the surface of solid can be obtained with sufficient accuracy by measuring the thickness of the solid or vice versa.

• 대한전기학회논문지:시스템및제어부문D
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• 제49권10호
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• pp.563-571
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• 2000

In this paper, a nonlinear adaptive control method for an EMS(Electro-Magnetic Suspension) system with mass uncertainty is proposed. Using the coordinate transformation and feedback linearizing control, EMS system has been transformed into the form of parametric strict-feedback system with unknown virtual control coefficients. With this transformed system, tuning functions approach, which is an advanced from of adaptive backstepping, has been applied in order to stabilize the system against mass uncertainty. Computer simulation is also carried out in order to compare the performance of the proposed controller with that of feedback linerizing controller.

• Tribology and Lubricants
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• 제30권2호
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• pp.86-91
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• 2014

This paper presents a design procedure for a face gear and pinion used in a handpiece with a $160^{\circ}\acute{y}$ contra angle and 1:2 gear ratio. Based on the geometric theory of gearing, the tooth profile of the face gear and pinion is developed. To analyze the contact pressure, the gear profile should be determined before calculating the stress between the two gears. The concept of calculating the face gear profile is that it can be generated by the coordinate transformation of the shaper profiles, which have involute curves, using a simulation method from the gear manufacturing process.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.389-390
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• 2006

The cycloidal reducer is one of the velocity controlling equipments in machinery. It has advantages of the higher reduction ratio, the higher accuracy, the easier adjustment of the transmission ratio and the smaller workspace than any other kinds of the reducers. This paper proposes a simple and exact approach for the lobe profile design of the two teeth difference cycloidal plate gear, which is different from the standard cycloidal reducer, by means of the principle of the instant velocity center in the general contact mechanism and the homogeneous coordinate transformation.

• 한국항공운항학회지
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• 제19권3호
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• pp.16-24
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• 2011

In this research, a cockpit display system using 3 dimensional geographic information was developed. A coordinate transformation method from WGS84 to TM was first studied. Octree data structure was used for efficient 2D and 3D graphic display. Also, a 3D graphic engine was developed for fast display with large amount of geographic data which can be practically used in aircraft onboard computer having low performance. This 3D engine contains additional function such as geographic and object information loading, many kinds of camera mode, aircraft position and rotation control function, character strip display. In the future research, actual GPS signal should be used and additional information that can help pilot's decision should be display.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2011년도 한국컴퓨터종합학술대회논문집 Vol.38 No.1(D)
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• pp.52-53
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• 2011

차세대 위치기반 서비스의 최종 형태는 실내외 구분 없이 서비스를 제공하여야 한다. 그러나 실내에서 정확한 GPS 정보를 얻기 힘들기 때문에 실내와 실외에서 서로 다른 측위방식이 사용되고 있다. 따라서 실내외 연속측위를 수행하기 위해서는 실내좌표의 값을 실외에서 사용하는 GPS 좌표로 변환할 수 있어야 한다. 본 논문에서는 실내측위 시 위치 변화에 GPS 변화율을 적용하여, 실내측위의 변화에 따라 GPS 값의 변화를 주어 실내에서도 GPS정보를 얻을 수 있는 방법을 제안한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 B
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• pp.647-649
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• 1998

This paper describes a robust stabilization of single input nonlinear systems with parametric uncertainty. We first investigate differential flatness of the nominal nonlinear systems. If a single input system is differentially flat, it possesses a flat output. And we define coordinate transformation functions via successively differentiating the flat output, and we also consider the robust fictitious controls at every differentiation of the flat output. In the new coordinates the nonlinear system is transformed into the Brunovsky normal form with matched uncertainty. With a robust control based on the Lyapunov method, the robust stabilization is achieved.

• 한국표면공학회지
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• 제24권3호
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• pp.125-136
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• 1991

a mathematical model is presented to describe the current distribution on a rotaing disk electrode under the galvanostatic pulse conlitions. A numerical technique by finite difference method to the transient convective diffusion equation, coordinate transformation and separation of variables to Laplace equation, and an iterative algorithm to solve the above equations simtltaneously with approximate boundary conditions were developed. An experimental investigated based on copper deposition in a copper sulfate-sulfuric acid system was performed and satisfactory agreement was obtained between expermental and theoretical current distribution. The current distribution of copper deposition is secondary current distribution within the experimental conditions. Dimensionless variables, N and J as well as Wagner number were used to determine the criteria for the uniformity of current distribution.