• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2005년도 제30회 춘계학술대회
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• pp.79-82
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• 2005

In this study, we have tested the feasibility of the convex non-linear objective model and the line search optimization method for the fluence map optimization (FMO). We've created the convex nonlinear objective function with simple bound constraints and attained the optimal solution using well-known gradient algorithms with an Armijo line search that requires sufficient objective function decrease. The algorithms were applied to 10 head-and-neck cases. The numbers of beamlets were between 900 and 2,100 with a 3 mm isotropic dose grid. Nonlinear optimization methods could efficiently solve the IMRT FMO problem in well under a minute with high quality for clinical cases.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.311-311
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• 2000

We propose a DP-based formulation for matching line patterns by defining a robust and stable geometric representation that is based on the conceptual organizations. Usually, the endpoint proximity and collinearity of image lines, as two main conceptual organization groups, are useful cues to match the model shape in the scene. As the endpoint proximity, we detect junctions from image lines. We then search for junction groups by using geometric constraint between the junctions. A junction chain similar to the model chain is searched in the scene, based on a local comparison. A Dynamic Programming-based search algorithm reduces the time complexity for the search of the model chain in the scene. Our system can find a reasonable matching, although there exist severely distorted objects in the scene. We demonstrate the feasibility of the DP-based matching method using both synthetic and real images.

• 한국정보통신학회논문지
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• 제19권11호
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• pp.2540-2545
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• 2015

본 논문에서는 복부 초음파 영상에서 충수를 추출하는 방법을 제안한다. 제안된 충수 추출 방법은 복부 초음파 영상에서 명암 대비를 강조하기 위해 Ends_in Search Stretching 기법을 적용하고, Max-Min 이진화, 영역 레이블링, 잡음제거, Cubic Spline 보간법을 적용하여 복부 근육의 하단 근막 부분을 추출한다. 그리고 초음파 영상에서 추출된 근막 영역을 제거한 후, ART2 알고리즘을 적용하여 충수를 추출한다. 제안된 방법을 초음파 영상에 적용한 결과, 제안된 충수 추출 방법이 효율적으로 충수가 추출되는 것을 영상의학과 전문의를 통하여 확인하였다.

• 제어로봇시스템학회논문지
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• 제17권2호
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• pp.145-148
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• 2011

In this paper, we proposed a search method for structured light pixels of omnidirectional structured light image. Since the omnidirectional structured light image is composed of several circular arc segments, the proposed algorithm searches the structured light pixels in radial direction rather than horizontal or vertical directions. The proposed search algorithm is based on the well-known Bresenham raster algorithm for line drawing in discrete integer space, thereby computation of the algorithm is very efficient. Comparison results between the proposed search algorithm and the conventional horizontal search are presented in experiments.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2004년도 춘계 종합학술대회 논문집
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• pp.377-384
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• 2004

필드 기반 영상 모핑은 제어선을 지정하는 과정의 대부분을 사용자의 수작업에 의존하기 때문에 작업 시간이 많이 소요될 뿐만 아니라 양질의 결과를 얻기 위해서는 숙련을 요하는 불편함이 있다. 본 논문은 소스 영상과 목표 영상에서 모핑 대상체 쌍의 형상 정보를 획득한 상태에서 사용자가 수동으로 최소한의 특징점 쌍만을 지정하면 이렇게 지정된 특징점 쌍을 기준 삼아 다각형 기반 정점 탐색에 의해 소스 영상파 목표 영상에 상호 대응되는 제어선들을 자동적으로 설정한 후, 제어선 길이의 비율과 제어선으로부터의 이격 거리를 이용하여 영상 모핑을 수행함으로써 영상 모핑의 반자동화를 실현할 수 있는 방법을 제안한다. 제안된 방법에 따르면, 사용자가 제어선을 설정하는 시간을 단축할 수 있고 비숙련자도 최소의 제어선만을 지정하여 자연스러운 로핑 결과를 획득할 수 있는 이점이 있다.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 1992년도 춘계공동학술대회 발표논문 및 초록집; 울산대학교, 울산; 01월 02일 May 1992
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• pp.10-11
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• 1992

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.1237-1240
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• 1996

This paper proposes a heuristic algorithm for performing the line balancing of PCB assembly fine including multiple surface mounters efficiently. We consider a PCB assembly line including the multiple surface mounters arranged serially as a target system. We assume that the number of heads of surface mounters can be changed. Also, the conveyor is assumed to move at a constant speed and have no buffer. Considering the minimum number of machines required for the desired production rate is a discrete nonincreasing function which is inversely proportional to the cycle time, we propose an optimization algorithm for line balancing by using the binary search method. Also we propose an head-changing algorithm. The algorithms are validated through the computer simulation.

• 한국유체기계학회 논문집
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• 제2권1호
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• pp.29-34
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• 1999

To develop the efficient numerical optimization method for the design of an airfoil, an evaluation of various methods coupled with two-dimensional Naviev-Stokes analysis is presented. Simplex method and Hook-Jeeves method we used as direct search methods, and steepest descent method, conjugate gradient method and DFP method are used as indirect search methods and are tested to determine the search direction. To determine the moving distance, the golden section method and cubic interpolation method are tested. The finite volume method is used to discretize two-dimensional Navier-Stokes equations, and SIMPLEC algorithm is used for a velocity-pressure correction method. For the optimal design of two-dimensional airfoil, maximum thickness, maximum ordinate of camber line and chordwise position of maximum ordinate are chosen as design variables, and the ratio of drag coefficient to lift coefficient is selected as an objective function. From the results, it is found that conjugate gradient method and cubic interpolation method are the most efficient for the determination of search direction and the moving distance, respectively.

• Nonlinear Functional Analysis and Applications
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• 제27권2호
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• pp.381-403
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• 2022

The main goal of this research is to solve variational inequalities involving quasimonotone operators in infinite-dimensional real Hilbert spaces numerically. The main advantage of these iterative schemes is the ease with which step size rules can be designed based on an operator explanation rather than the Lipschitz constant or another line search method. The proposed iterative schemes use a monotone and non-monotone step size strategy based on mapping (operator) knowledge as a replacement for the Lipschitz constant or another line search method. The strong convergences have been demonstrated to correspond well to the proposed methods and to settle certain control specification conditions. Finally, we propose some numerical experiments to assess the effectiveness and influence of iterative methods.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 B
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• pp.952-954
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• 2002

The effort for measuring the rotor vibration caused by the short of rotor winding or air-gap eccentricity has been carried on. This paper introduces on-line vibration monitoring technologies using search coils to measure flux for synchronous generators. A 3,300/6,600 (V), 150 [kW] synchronous generator is built, and search coils are designed and inserted in the wedges. Furthermore, air-gap eccentricity is analyzed by finite element method and compared with experiment tests. Induced voltages caused by different air-gap eccentricity on the search coils are compared as well.