• ETRI Journal
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• 제35권6호
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• pp.1011-1020
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• 2013

In this paper, we present a method for obtaining a high-quality 3D depth. The advantages of active pattern projection and passive stereo matching are combined and a system is established. A diffractive optical element (DOE) is developed to project the active pattern. Cross guidance (CG) and auto guidance (AG) are proposed to perform the passive stereo matching in a stereo image in which a DOE pattern is projected. When obtaining the image, the CG emits a DOE pattern periodically and consecutively receives the original and pattern images. In addition, stereo matching is performed using these images. The AG projects the DOE pattern continuously. It conducts cost aggregation, and the image is restored through the process of removing the pattern from the pattern image. The ground truth is generated to estimate the optimal parameter among various stereo matching algorithms. Using the ground truth, the optimal parameter is estimated and the cost computation and aggregation algorithm are selected. The depth is calculated and bad-pixel errors make up 4.45% of the non-occlusion area.

• 한국CDE학회논문집
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• 제14권1호
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• pp.10-17
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• 2009

Surface detection and parameter estimation in point cloud is a relevant subject in CAD/CAM, reverse engineering, computer vision, coordinate metrology and digital factory. In this paper we present a software for a fully automatic surface detection and parameter estimation in unordered, incomplete and error-contaminated point cloud with a large number of data points. The software consists of three algorithmic modules each for object identification, point segmentation, and model fitting, which work interactively. Our newly developed algorithms for orthogonal distance fitting(ODF) play a fundamental role in each of the three modules. The ODF algorithms estimate the model parameters by minimizing the square sum of the shortest distances between the model feature and the measurement points. We demonstrate the performance of the software on a variety of point clouds generated by laser radar, computer tomography, and stripe-projection method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 전기.전자공학 학술대회 논문집(I)
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• pp.144-147
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• 1987

An adaptive control algorithm for a plant with unmodelled dynamics is proposed. The upper bounds of the output due to the unmodelled dynamics and measurement noise is assumed to be known. Linear programming is used in estimating the bounds of plant parameters. Projection type algorithm is used in estimating the plant parameter with these bounds. This algorithm is nearly the same as those proposed by Kreisselmeier or Middleton except that the bounds are computed by linear programming. The stability of the proposed algorithm Can be proved in nearly the same way as that of Middleton. Simulation results show that the proposed algorithm gives better parameter convergence and smaller overshoot in the plant output than the algorithm without computing the bounds of plant parameters by linear programming.

• 한국농공학회논문집
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• 제54권5호
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• pp.141-153
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• 2012

In this study, we estimated probable precipitation amounts at the target year (2020, 2030, 2040) of 55 weather stations in Korea using the 24 hour annual maximum precipitation data from 1973 through 2009 which should be useful for management of agricultural reservoirs. Not only trend tests but also non-stationary tests were performed and non-stationary frequency analysis were conducted to all of 55 sites. Gumbel distribution was chosen and probability weighted moment method was used to estimate model parameters. The behavior of the mean of extreme precipitation data, scale parameter, and location parameter were analyzed. The probable precipitation amount at the target year was estimated by a non-stationary frequency analysis using the linear regression analysis for the mean of extreme precipitation data, scale parameter, and location parameter. Overall results demonstrated that the probable precipitation amounts using the non-stationary frequency analysis were overestimated. There were large increase of the probable precipitation amounts of middle part of Korea and decrease at several sites in Southern part. The non-stationary frequency analysis using a linear model should be applicable to relatively short projection periods.

• Ecology and Resilient Infrastructure
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• 제10권4호
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• pp.208-216
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• 2023

본 연구의 목표는 실용적인 표면영상유속계를 만들기 위해 가장 적절한 하드웨어와 소프트웨어의 구성을 제시하는 것이다. 실용적인 표면영상유속계 구성을 위해 하드웨어로 CCTV를 선택하고, 2분 간격으로 30초간의 영상을 지속적으로 촬영하는 장비를 구성하였다. 촬영된 동영상을 분석하는 소프트웨어에는 11-변수 투영법을 적용하여 변화하는 수위에 따라 정확한 측정점을 재구성하도록 하였다. 아울러 각 측정점에서 주흐름방향으로 정확한 시공간영상을 작성할 수 있도록 시공간영상 작성법을 제안하였다. 제안된 방법으로 구성된 표면영상유속계를 제작하여 인수천에 시험적용하여 호우 사상에 대해 검토한 결과 정확하고 신속하며 연속적인 유량측정이 가능하였다.

• Journal of the Korean Data and Information Science Society
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• 제26권2호
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• pp.347-354
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• 2015

본 논문은 균형불완비블럭설계 (balanced incomplete block design)의 자료분석에 사영을 이용한 블럭내 분석 (intrablock analysis)방법을 다루고 있다. 블럭내 분석을 위해 단계별 방법 (stepwise procedure)에서 유도되는 분석모형을 이용하고 있다. 단계별 방법의 적용으로 인해 모형행렬로 주어지는 사영공간이 변동요인에 따른 부분공간들로 직교분할됨을 보여주고 있다. 단계별 과정에서 변동요인에 따른 변동량을 구하기 위해 해당하는 효과벡터의 계수행렬에 근거한 사영의 구조적 형태를 기술하고 있으며 상호직교하는 부분공간으로의 사영을 이용하여 블럭효과에 적합된 처리효과의 변동량를 구하는 과정을 구체적으로 다루고 있다. 또한, 사영에 의해 처리효과를 구하는 과정을 제시하고 있으며 단계별로 잔차벡터를 이용하여 모형설정하는 방법과 고유벡터에 의한 추정가능함수의 구성과 추정가능성을 논의하고 있다.

• 한국통신학회논문지
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• 제29권10C호
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• pp.1402-1413
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• 2004

비강체 (non-rigid) 영상 등록에서 추정되는 좌표변환은 가역이어야 함으로 그 변환의 Jacobian 행렬식은 항상 양수 값을 가져야 한다. 본 논문에서는 이러한 가역 조건을 만족하는 좌표변환의 조건을 gradient 크기 제한의 조건으로 구한다. 또한 cubic B-spline을 이용한 변환 모델의 경우, 이 gradient 크기 제한 조건을 만족시키는 인수 집합을 이웃한 두 계수들의 차이가 제한된 인수들의 집합으로 구하였다. 이러한 인수들의 집합은 half space들의 교집합으로 이루어진 convex 집합이다. 본 논문에서는 이 convex 집합에 속하는 인수로 구성되는 좌표변환들 중에서 유사지수 (similarity measure) 를 최대로 만드는 변환을 gradient projection 최적화 기법을 통해 발견하였다. 이론적 분석, 폐 CT (Computed Tomography) 영상을 이용한 시뮬레이션 및 실험을 통하여, 제안된 알고리즘의 성능이 벌칙 함수 penalty function) 를 이용하는 기존의 방법보다 우수함을 증명하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 학술대회 논문집 정보 및 제어부문
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• pp.177-178
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• 2008

An LMI-based method for robust $L_2-L_{\infty}$ filter design is proposed for poly topic uncertain time-delay systems. By using the Projection Lemma and a suitable linearizing transformation, a strict LMI condition for $L_2-L_{\infty}$ filter design is obtained, which does not involve any iterations for design-parameter search, any couplings between the Lyapunov and system matrices, nor any system-dependent filter parameterization. Therefore, the proposed condition enables one to easily adopt, with help of efficient numerical solvers, a parameter-dependent Lyapunov function approach for reducing conservatism, and to design both robust and parameter-dependent filters for uncertain and parameter-dependent time-delay systems, respectively.

• 한국측량학회지
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• 제11권2호
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• pp.27-34
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• 1993

정확하고 경제성 있는 지형정보의 구축은 각종 건설공사를 비롯한 국토종합개발에 기본 요건으로서 그 중요성이 강조되고 있다. 본 연구에서는 남한 지역을 대상으로 하는 광역망과 충남·북 일원의 지역망내, 1, 2 등 삼각점에 대한 GPS 관측을 수행하여 WGS 84 좌표를 조정·산출하고 Bessel 타원체 상의 좌표로 변환하기 위한 변환계수론 Bessel Geoid Undulation을 고려한 7-Parameter 변환기법으로 도출하므로서, GPS에 의한 정밀 3차원 지형정보의 획득은 물론, 순변환된 성과와 역변환된 성과에 각각 T.M. 및 U.T.M 투영도법을 적용하여 정밀 지도제작을 위한 기본 자료의 산출 가능성을 제시코자 한다.

• 대한기계학회논문집B
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• 제29권1호
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• pp.87-94
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• 2005

A computer code for Electrical Capacitance Tomography (ECT) is developed to sense the cross sectional phase distribution of two-phase flow in the rectangular pipe in which the tomography sensor furnished by the insulated wall, electrodes, and electric field screen. The computer code had two steps for the image reconstruction. In the forward projection step, the sensitivity matrix was constructed based on the electric field calculated by the finite difference method. In the backward projection step, the sensitivity matrix and the measured capacitances were used to reconstruct the cross sectional image. Several algorithms including LBP, TR, ITR, and PLI were employed to find the proper one for the two-phase flow analysis. Since the dielectric constant of the water in two-phase flow is sensitive to the thermal parameter such as, temperature and pressure, the developed code was evaluated to find their accuracy, speed of calculation, and sensitivity to the variation of the dielectric constant. It was found that the iterative methods are superior to the direct methods for the image reconstruction, and the PLI method was the best in the variation of the dielectric constants.