• 한국디자인학회:학술대회논문집
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• 한국디자인학회 2002년도 봄 학술발표회 논문집
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• pp.190-191
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• 2002

• 한국정밀공학회지
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• 제3권4호
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• pp.53-63
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• 1986

In this study, the stress distribution of rectangular bar under torsion, when warping of both ends is free or constrained, is investigated. Method of separation of variable and Fourier Series are used for the theoretical analysis, and 3dimensional photoelastic stress-freezing method for experimental analysis. The main results are as follows; 1) In the case of warping-constrained rectangular bar, the normal stresses are negligible because they are less then 0.5% of the shear stresses. The maximum normal stress is placed on the point of y=0.61 b when b/a=1 and it gradually moves to the corner y=b when the value of b/a is increased. 2) According to increase of the value of b/a, on the crossection, the maximum shear stress is placed on the middle point of the long side (x=${\pm}a$, y=0) when warping of both ends is free but the middle of the short side (x=0, y=${\pm} b$) when warping is constrained. The stress distribution is straight line when warping is constrained, namely, the stress distribution is proportional to the distance from the axis of centroid, but parabolic when warping is free. 3) The values of the combined stress of warping-constrained bar, if the influence of the loaded point is neglected, are generally smaller than those of warping-free.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2005년도 가을 학술발표논문집 Vol.32 No.2 (2)
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• pp.952-954
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• 2005

The objective of this paper is to propose the image interpolation method with pseudomedian filter for Field warping and morphing, and to evaluate and analyze its subjective image quality. The Field warping relatively gives rise to more computing overhead, but it can use the control line to control the warping result with more elaboration. Due to the working characteristics of the image warping and morphing process, various complex geometrical transformations occur and a image interpolation technique is needed to effectively process them. Of the various interpolation techniques, bilinear interpolation which shows above average performance is the most widely used. However, this technology has its limits in the reconstructivity of diagonal edges. The proposed interpolation method is to efficiently combine the bilinear interpolation and the pseudomedian filter0based interpolation which shows good performance in the reconstructivity of diagonal edges. According to the proposed interpolation method, we could get more natural warping and morphing results than other interpolation methods.

• 제어로봇시스템학회논문지
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• 제22권8호
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• pp.643-649
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• 2016

This paper presents a new image cache algorithm for real-time implementation of high-resolution color image warping. The cache memory is divided into four cache memory modules for simultaneous readout of four input image pixels in consideration of the color filter array (CFA) pattern of an image sensor and CFA image warping. In addition, a pipeline structure from the cache memory to an interpolator is shown to guarantee the generation of an output image pixel at each system clock cycle. The proposed image cache algorithm is applied to an FPGA-based real-time color image warping, and experimental results are presented to show the validity of the proposed method.

• Kyungpook Mathematical Journal
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• 제55권3호
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• pp.741-752
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• 2015

We introduce the warping crossing polynomial of an oriented knot diagram by using the warping degrees of crossing points of the diagram. Given a closed transversely intersected plane curve, we consider oriented knot diagrams obtained from the plane curve as states to take the sum of the warping crossing polynomials for all the states for the plane curve. As an application, we show that every closed transversely intersected plane curve with even crossing points has two independent canonical orientations and every based closed transversely intersected plane curve with odd crossing points has two independent canonical orientations.

• Structural Engineering and Mechanics
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• 제61권1호
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• pp.31-47
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• 2017

As a relatively new type of multi-layered rubber-based seismic isolators, fiber-reinforced elastomeric isolators (FREIs) are composed of several thin rubber layers reinforced with flexible fiber sheets. Limited analytical studies in literature have pointed out that "warping" (distortion) of reinforcing sheets has significant influence on buckling behavior of FREIs. However, none of these studies, to the best knowledge of authors, has investigated their warping behavior, thoroughly. This study aims to investigate, in detail, the warping behavior of strip-shaped FREIs by deriving advanced analytical solutions without utilizing the commonly used "pressure", incompressibility, inextensibility and the "linear axial displacement variation through the thickness" assumptions. Studies show that the warping behavior of FREIs mainly depends on the (i) aspect ratio (shape factor) of the interior elastomer layers, (ii) Poisson's ratio of the elastomer and (iii) extensibility of the fiber sheets. The basic assumptions of the "pressure" method as well as the commonly used incompressibility assumption are valid only for isolators with relatively large shape factors, strictly incompressible elastomeric material and nearly inextensible fiber reinforcement.

• 한국게임학회 논문지
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• 제14권2호
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• pp.55-66
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• 2014

영상 워핑은 입력 영상을 주어진 조건에 적합하게 변형하는 기술로, 최근 영화나 애니메이션 분야에서 캐릭터의 얼굴 형상을 변형하는데 활용되고 있다. 얼굴 특징을 기반으로 형상을 변형하는 워핑 방법 가운데 하나인 메쉬 워핑은 입력 영상에서 눈, 코, 입 주변의 사각형 모양의 메쉬 그룹을 형성하여 1:1정합시킴으로써 워핑 영상을 생성하는 방법이다. 이는 메쉬 제어점 좌표에 오차가 있거나 작은 면적의 메쉬로 세분화되어 생성된 경우 메쉬들의 경계 선분에서 결과 영상이 일그러지는 문제점이 있다. 본 연구는 얼굴의 자연스러운 워핑 영상을 생성하는 과정에서 오류 발생을 최소로 하며 정확한 결과를 적은 연산량과 시간에 처리하기 위해 삼각형기반의 영상 보간 기법을 제안한다. 우선 얼굴을 대표하는 특징점들을 찾고 이들을 연결하여 기본 삼각형 메쉬를 구성한다. 제안하는 방법은 기존의 메쉬 워핑과 비교하여 연산 처리량과 시간은 단축되면서 워핑 과정에서의 오류 발생을 줄일 수 있음을 실험으로 보인다.

• 대한원격탐사학회지
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• 제26권4호
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• pp.439-449
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• 2010

이 논문에서는 KOMPSAT-2 스테레오 영상의 PAN밴드에 존재하는 미세한 크기의 Y시차가 발생하는 원인을 규명하고 이를 개선하기 위한 일련의 실험 및 분석과정을 보고한다. 분석결과, Y시차가 발생하는 원인이 KOMPSAT-2 영상을 생성할 때 PAN밴드를 MS밴드와 일치하도록 Warping처리하는 과정에서 발생한 Resampling 오차 때문인 것으로 판단할 수 있었다. 또한 엄밀한 PAN밴드의 Warping 방식을 적용하여 Resampling 오차를 제거함으로써 Y 시차문제가 상당부분 개선될 수 있음을 확인하였다. 또한 KOMPSAT-2 영상 PAN밴드에서 관측된 밝기값 밀림현상도 엄밀한 Warping처리를 통해서 개선될 수 있음을 확인하였다. 따라서, 보다 엄밀한 Warping기법이 KOMPSAT-2 영상처리과정에 적용될 수 있다면 KOMPSAT-2 영상의 기하정확도 및 복사정확도가 많이 개선될 수 있을 것으로 기대한다.

• 산업기술연구
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• 제21권A호
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• pp.167-179
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• 2001

This paper discusses an index-based subsequence matching that supports time warping in large sequence databases. Time warping enables finding sequences with similar patterns even when they are of different lengths. In earlier work, we suggested an efficient method for whole matching under time warping. This method constructs a multidimensional index on a set of feature vectors, which are invariant to time warping, from data sequences. For filtering at feature space, it also applies a lower-bound function, which consistently underestimates the time warping distance as well as satisfies the triangular inequality. In this paper, we incorporate the prefix-querying approach based on sliding windows into the earlier approach. For indexing, we extract a feature vector from every subsequence inside a sliding window and construct a multi-dimensional index using a feature vector as indexing attributes. For query precessing, we perform a series of index searches using the feature vectors of qualifying query prefixes. Our approach provides effective and scalable subsequence matching even with a large volume of a database. We also prove that our approach does not incur false dismissal. To verily the superiority of our method, we perform extensive experiments. The results reseal that our method achieves significant speedup with real-world S&P 500 stock data and with very large synthetic data.

• 대한조선학회논문집
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• 제33권1호
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• pp.77-89
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• 1996

Mindlin 판이론에 바탕을 둔 두꺼운 판의 굽힘문제에 대한 유한요소 개발에 많은 연구가 수행되어 왔다. 두꺼운 판의 전단변형을 고려하기 위하여 주로 근사적인 일정전단회전각이론(CSAT)을 사용하여 왔지만, 두께가 두꺼워질수록 단면의 전단변형의 영향을 효과적으로 고려할 수 없을 것이다. 판 단면의 워핑(warping)을 가능한 정확하게 나타내는 것이 바람직할 것이다. 본 논문은 전단변형과 전단워핑의 영향을 고려한 새로운 판의 이론을 전개하고, Mindlin 판이론에 의한 결과와 비교 검토하기 위하여 다양한 파라미터 연구를 수행하여 두꺼운 판에 대한 전단변형과 전단워핑의 영향을 좀 더 깊이 고찰하고자 한다.