• 호남수학학술지
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• 제41권4호
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• pp.823-835
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• 2019

A solution for Nevanlinna-Pick interpolation problem with low complexity is constructed via non-recursive method. More precisely, a stable rational function satifying the given interpolation data in the complex right half plane is found by solving a homogeneous interpolation problem related to a minial interpolation problem for the given data in the right half plane together with its mirror-image data.

• ETRI Journal
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• 제31권6호
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• pp.675-679
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• 2009

$Ti_xSi_{1-x}O_y$ (TSO) thin films are fabricated using plasma-enhanced atomic layer deposition. The Ti content in the TSO films is controlled by adjusting the sub-cycle ratio of $TiO_2$ and $SiO_2$. The refractive indices of $SiO_2$ and $TiO_2$ are 1.4 and 2.4, respectively. Hence, tailoring of the refractivity indices from 1.4 to 2.4 is feasible. The controllability of the refractive index and film thickness enables application of an antireflection coating layer to TSO films for use as a thin film solar cell. The TSO coating layer on an Si wafer dramatically reduces reflectivity compared to a bare Si wafer. In the measurement of the current-voltage characteristics, a nonlinear coefficient of 13.6 is obtained in the TSO films.

• 제어로봇시스템학회논문지
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• 제6권6호
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• pp.462-470
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• 2000

This paper proposes a visual servoing method based on QR decomposition and disturbance observer. The QR decomposition factors the image feature Jacobian into a unitary matrix and an upper triangular matrix. And it is shown that several performance indices such as measurement sensitivity of visual features, sensitivity of the control to noise and controllability can be improved for any general image feature Jacobian by QR decomposition and disturbance observer. To show the validity of the proposed approach, visual servoing with stereo vision is carried out for a Samsung FARAMAN 6-axis industrial robot manipulator.

• 대한전기학회논문지:전력기술부문A
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• 제48권10호
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• pp.1311-1316
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• 1999

A visual servoing method has been proposed based on disturbance observer to eliminate the effect of the off-diagonal component of image feature Jacobian, since performance indices such as measurement sensitivity of visual features, sensitivity of the control to noise and controllability could be improved when an image feature Jacobian was given as a block diagonal matrix. In this paper, experimental results of disturbance observer-based visual servoing are discussed where Samsung FARAMAN-AS1 6-axis industrial robot manipulator is employed. Also, the feature saturator is proposed to stabilize the disturbance observer loop by saturating the differential changes of the image features.

• 대한전기학회논문지:전력기술부문A
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• 제49권3호
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• pp.136-141
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• 2000

This paper presents the design of an H$\infty$ based robust Static Synchronous Compensator (STATCOM) supplementary controller to suppress the subsynchronous resonance (SSR) in the series-compensated system. The IEEE second benchmark, System-l model is employed for this study. In order to design the effective controller, the modal controllability and observability indices to the oscillation modes are considered. Comprehensive time domain simulations using a nonlinear system model that the proposed STATCOM supplementary controller can suppress the SSR efficiently in spite of the variations of power system operating conditions.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 G
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• pp.2312-2314
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• 1998

To improve the visual servoing performance, several strategies were proposed in the past such as redundant feature points, using a point with different height and weighted selection of image features. The performance of these visual servoing methods depends on the configuration between the camera and object. And redundant feature points require much computation efforts. This paper proposes the visual servoing m based on the disturbance observer, which compe the upper off-diagonal component of image fe Jacobian to be null. The performance indices su sensitivity for a measure of richness, sensitiv the control to noise, and controllability are sho improved when the image feature Jacobian is giv a block diagonal matrix. Computer simulation carried out for a PUMA560 robot and show results to verify the effectiveness of the pro method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 G
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• pp.3077-3079
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• 1999

A visual servoing method has been proposed based on disturbance observer to eliminate the effect of the off-diagonal component of image feature Jacobian, since performance indices such as measurement sensitivity of visual features, sensitivity of the control to noise and controllability could be improved when an image feature Jacobian was given as a block diagonal matrix. In this paper, experimental results of disturbance observer-based visual servoing are discussed where Samsung FARAMAN-ASl 6-axis industrial robot manipulator is employed. Also, the feature saturator is proposed to stabilized the disturbance observer loop by saturating the differential changes of the image features.

• 한국산학기술학회논문지
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• 제13권2호
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• pp.615-627
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• 2012

스마트폰의 본격적인 보급은 이후 관련 산업 전반에 큰 변화를 가져왔다. 휴대폰 시장은 물론 스마트폰 애플리케이션 시장 역시 급격하게 성장하며 애플리케이션을 개발하는 소규모 개발사들 간의 경쟁이 심화되고 있다. 그러나 경쟁의 심화와 높은 시장진입 비용으로 인해 애플리케이션 개발사들은 사용자 관점에서의 접근을 바탕으로 한 애플리케이션 자체의 품질제고가 필요하다는 주장을 제기하고 있다. 그러나 스마트폰 애플리케이션 사용자 관점에 대한 연구는 아직 초기단계로 다양한 접근에서 이루어지지 못한 실정이다. 이에 따라 본 연구에서는 근거이론의 개방형 코딩방법에 따라 국내 포털사이트의 관련 커뮤니티와 블로그를 대상으로 애플리케이션에 대한 리뷰 데이터 수집을 진행하여 사용자들이 애플리케이션 사용시 중요하게 고려하는 지표들을 도출하였다. 아울러 각 지표들이 노출되는 빈도를 계산하여 지표간의 비교분석을 하였다. 연구결과 사용자들은 애플리케이션 사용시 유희성과 통제가능성, 다양성, 사용용이성 등 총 30개의 하위범주에 속하는 지표들을 중요하게 생각하고 있었으며 하위범주들은 5개의 상위 범주로 분류되었다. 상위범주는 감성, 디자인, 기술, 가격, 사회성의 다섯가지로 구성된다. 본 연구의 결과는 애플리케이션 개발사들에게 사용자 니즈를 바탕으로 개발을 할 수 있는 디자인과 개발의 가이드라인을 제시하고 있으며 추후 심화 연구를 통하여 실제 애플리케이션들의 사용성 평가 도구 개발의 근거로 활용할 수 있을 것이다.