• 전자공학회논문지S
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• 제34S권10호
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• pp.120-131
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• 1997

This paper prsents a new method that automatically recognizes the dimension lines (consisting of shape lines, tail lines and extension lines) from the mechanical drawings. In the proposed method, the object and closed-loop symbols are separated from the character-free drawings. Then the object lines and interpretation lines are vectorized by using several techniques such as thinning, line-vectorization, and vector-clustering. Finally, after recognizing arrowheads by using pattern matching, we recognize dimension lines from interpretation lines by using arrohead's directional vector and centroid. By using the methods of geometric modeling and mathematical operation, the proposed method readility recognizes the dimension lines from complex drawings. Experimental resuls are presented, which are obtained by applying the proposed method to drawings drawn in compliance with the KS drafting standard.

• Structural Engineering and Mechanics
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• 제10권2호
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• pp.93-110
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• 2000

An alternative interpretation of the completeness requirements for the higher order elements is presented. Apart from the familiar condition, $\sum_iN_i=1$, some additional conditions to be satisfied by the shape functions of higher order elements are identified. Elements with their geometry in the natural form, i.e., without any geometrical distortion, satisfy most of these additional conditions inherently. However, the geometrically distorted elements satisfy only fewer conditions. The practical implications of the satisfaction or non-satisfaction of these additional conditions are investigated with respect to a 3-node bar element, and 8- and 9-node quadrilateral elements. The results suggest that non-satisfaction of these additional conditions results in poorer performance of the element when the element is geometrically distorted. Based on the new interpretation of completeness requirements, a 3-node element and an 8-node rectangular element that are insensitive to mid-node distortion under a quadratic displacement field have been developed.

• 한국측량학회지
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• 제20권3호
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• pp.235-242
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• 2002

고해상도의 IKONOS 위성 영상데이터로부터 도로 정보를 판독.추출하고 그 정확도를 분석하고자 하였다. RFM을 이용하여 기하보정영상을 생성한 후, 이 영상으로부터 도로를 판독하고 스크린디지타이징 하였다. 도로 판독 및 추출 정확도를 평가하기 위하여 도로 경계선의 위치와 도로 폭을 수치지도와 비교한 결과, 도로 경계선은 $\pm$3.4m, 도로의 폭은 $\pm$1.1m의 정확도로 추출되었다.

• 로봇학회논문지
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• 제11권1호
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• pp.9-18
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• 2016

A rectangle-based relative localization method is proposed for a mobile robot based on a novel geometric formulation. In an artificial environment where a mobile robot navigates, rectangular shapes are ubiquitous. When a scene rectangle is captured using a camera attached to a mobile robot, localization can be performed and described in the relative coordinates of the scene rectangle. Especially, our method works with a single image for a scene rectangle whose aspect ratio is not known. Moreover, a camera calibration is unnecessary with an assumption of the pinhole camera model. The proposed method is largely based on the theory of coupled line cameras (CLC), which provides a basis for efficient computation with analytic solutions and intuitive geometric interpretation. We introduce the fundamentals of CLC and describe the proposed method with some experimental results in simulation environment.

• 대한수학교육학회지:학교수학
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• 제3권2호
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• pp.281-294
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• 2001

As a measure of the center of data, arithmetical mean, median, mode, harmonic mean and geometric mean are generally used. Students must learn qualitative aspect of average values as well as its calculation for its adequate use. As the result of the learning, they should be able to select the appropriate average value according to the characteristic of data and problem context. For this object, the historical origin and visual interpretation of average values were introduced in this paper. And to help teaching several meanings of average values, several examples including context were suggested.

• 한국정밀공학회지
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• 제11권5호
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• pp.88-97
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• 1994

We persent a method for kinematic calibration of open chain mechanisms based on the product of exponentials (POE) formula. The POE formula represents the forward kinematics of an open chain as a product of matrix exponentials, and is based on a modern geometric interpretation of classical screw theory. Unlike the kinematic parameters in the POE formula vary smoothly with changes in the joint axes;ad hoc methods designed to address the inherent singularities in the D-H parameters are therefore are therefore unnecessary. After introducing the POE formula, we derive a least-squares kinematic calibration algorithm for general open chain mechanisms. Simulation results with a 6-axis open chain are presented.

• Communications for Statistical Applications and Methods
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• 제3권1호
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• pp.11-19
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• 1996

Canonical correlation analysis is a multivariate technique for identifying and quantifying the statistical relationship between two sets of variables. Like most multivariate techniques, the main objective of canonical correlation analysis is to reduce the dimensionality of the dataset. It would be particularly useful if high dimensional data can be represented in a low dimensional space. In this study, we will construct statistical graphs for paired sets of multivariate data. Specifically, plots of the observations as well as the variables are proposed. We discuss the geometric interpretation and goodness-of-fit of the proposed plots. We also provide a numerical example.

• 한국수학교육학회지시리즈A:수학교육
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• 제25권3호
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• pp.57-69
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• 1987

A geometric interpretation of t-designs, in the context of posets, is given in the association scheme, not isomorphic with the Hamming scheme H(2,4), but having the same parameters as H(2,4). It is also shown that there is no similar poset which characterizes the designs for ally of the three exceptional association schemes, not isomorphic with the Johnson scheme J(8,2), but having the same parameters as J(8,2).

• 한국HCI학회논문지
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• 제8권1호
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• pp.19-28
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• 2013

문화 자연유산 분야에서 3차원 스캐닝 기술은 아직 기록과 보존, 모니터링의 도구로 활용 폭이 제한되어 있으며, 전문가들에 의해 직접 활용되지 못하고 있다. 스캔 데이터의 정밀한 기하 정보는 효과적인 가시화를 통해 전문가들의 과학적 해석을 가능하게 할 수 있다. 본 연구에서는 이를 위해 스캔 모델로부터 필요한 기하 특성을 가시화하는 렌더링 기법들을 분석하고, 스캔 데이터의 가시화 파이프라인과 렌더링 기법 및 이의 분류 체계를 제시하였다. 또한 사례연구로서, 공룡발자국 분야의 기존 연구 방법을 분석하여 문제점을 도출하고, 이에 따라 스캔 모델을 가시화하여 전문가를 대상으로 테스트를 수행하였으며 이를 통해 효과성을 확인하였다. 본 연구는 3차원 스캔 데이터를 이용하여 문화 및 자연유산을 효과적으로 해석할 수 있는 실용적 방안을 제시하였음에 의의가 있다.

• 해양환경안전학회지
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• 제28권4호
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• pp.499-506
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• 2022

자율운항선박이 상용화되어 연안을 항해하기 위해서는 해상의 장애물을 탐지할 수 있어야 한다. 연안에서 가장 많이 볼 수 있는 장애물 중의 하나는 양식장의 부표이다. 이에 본 연구에서는 YOLO 알고리즘을 이용하여 해상의 부표를 탐지하고, 카메라 영상의 기하학적 해석을 통해 선박으로부터 떨어진 부표의 거리와 방위를 계산하여 장애물을 시각화하는 해상물체탐지시스템을 개발하였다. 1,224장의 양식장 부표 사진으로 해양물체탐지모델을 훈련시킨 결과, 모델의 Precision은 89.0 %, Recall은 95.0 % 그리고 F1-score는 92.0 %이었다. 얻어진 영상좌표를 이용하여 카메라로부터 떨어진 물체의 거리와 방위를 계산하기 위해 카메라 캘리브레이션을 실시하고 해상물체탐지시스템의 성능을 검증하기 위해 Experiment A, B를 설계하였다. 해상물체탐지시스템의 성능을 검증한 결과 해상물체탐지시스템이 레이더보다 근거리 탐지 능력이 뛰어나서 레이더와 더불어 항행보조장비로 사용이 가능할 것으로 판단된다.