• 융합신호처리학회논문지
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• 제13권4호
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• pp.180-186
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• 2012

본 연구에서는 육각형상을 포함하는 잡음이 많은 저 대비 영상으로부터 에지를 검출하는 방법을 제안한다. 이 방법은 라플라시안-가우시안 필터의 조합과 형상에 의존하는 필터의 아이디어에 기초하고 있다. 먼저, 모퉁이에서 특히 육각형의 에지를 검출하기 위한 검출기로서 6 개의 마스크를 갖는 알고리즘을 사용한다. 여기에서 두 개의 삼각화살 모양의 필터는 육각형의 삼각화살 모양의 접속부를 검출하기 위해 사용되고, 나머지 네 개의 마스크는 육각형 에지의 선성분을 강조하기 위해 사용된다. 자연영상으로서 보통 규칙적인 육각형상의 각막 내피 세포를 선택하며, 이 각막 내피 세포내 육각형상의 에지 검출은 임상 진단에 있어서 중요하다. 그 다음, 에지 검출법의 유효성을 평가하기 위해 제안 알고리즘과 기존 방법을 잡음을 포함하는 육각형 영상에 적용한 결과 본 제안 방법이 다른 방법에 비해 신호 대 잡음비와 에지의 일치율 및 검출 정확도에서 잡음에 대한 강인성과 양호한 검출 능력을 나타낸다.

• 한국기계가공학회지
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• 제16권5호
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• pp.63-68
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• 2017

This study determines the selection of an appropriate jig material for the blade edge of the medical sapphire knife. The physical properties of the jig material affects the edge shape and chipping phenomenon in machining of the medical sapphire knife. If a grinding wheel is used, brittle workpieces such as sapphire are easily damaged by the propagation of cracks because the grinding force significantly increases. It is important to constantly maintain the grinding force in the grinding process of the brittle materials. The grinding force can be kept constantly by inducing the elastic deformation of the Jig material because the elastic deformation of brittle work-piece is negligibly low. The chipping phenomenon may be reduced by selecting the proper Jig material. Aluminum, copper, stainless steels and carbon steel were used as Jig materials. The experiment was conducted using a cast iron grinding wheel, which was installed on a conventional grinding machine with the ELID grinding system. The thickness and width of the chipping area were measured using an optical microscope and FE-SEM to analyze the shape of the blade edge. According to the experiment result, the chipping phenomenon decreased, and the sharp edge was formed when the jig materials with low elastic modulus were used.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년 영문 학술대회
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• pp.168-172
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• 2008

Three different geometry shapes of the blade leading edge in a centrifugal compressor were investigated in this paper. Numerical simulation was done to analyze the effect of the leading edge shape on the performance of the centrifugal compressor. The result shows that compared to the blunt leading edge, the circular leading edge will raise the chocking mass flow. The pressure ratio and efficiency will increase obviously. Using elliptical leading edge will get a further improvement on the performance than circular leading edge. The analysis of the flow field shows that the leading edge often causes flow separation near the inlet; using circular leading edge and elliptical leading edge will reduce the separation. What's more, using circular and elliptical leading edge will also reduce the wake loss near the outlet of the impeller. In a centrifugal compressor, using circular or elliptical leading edge on the splitter will improve the pressure loading distribution of main blade near the position of the splitter leading, which will increase the pressure ratio.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2022년도 추계학술대회
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• pp.136-138
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• 2022

에지 검출은 영상에 대하여 물체의 모양, 위치, 크기 및 재질 등과 같은 정보를 포함하고 있으며, 영상의 특징을 분석할 때 매우 중요한 요소이다. 기존의 에지 검출 방법에는 1차 미분을 이용한 소벨 필터(Sobel edge detection filter), 로버츠 필터(Roberts edge detection filter), 프리윗 필터(Prewitt edge detect ion filter) 등이 있으며, 2차 미분을 이용한 LoG(Laplacian of Gaussian) 등이 있다. 하지만 이러한 방법들은 전체 영상 영역에 대해 고정된 가중치 마스크를 적용하기 때문에 에지 검출 결과가 다소 미흡하다는 단점이 있다. 따라서 본 논문에서는 마스크 내의 중심 화소를 고려하여 에지 검출 특성을 높이는 에지 검출 알고리즘을 제안한다. 또한 제안한 에지 검출 성능을 확인하기 위하여 시뮬레이션 결과 영상을 통해 비교하였다.

• 한국정밀공학회지
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• 제16권7호
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• pp.188-195
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• 1999

Cutting edge plays an important role in generating machined surface. In order to consider the geometric effects of the cutting edge on mechanical states, the concept of ploughing force and stagnation point was introduced which explains the generating mechanism of machined surface during cutting. The effects of edge radius and nose radius of cutting tool on the distribution of residual stresses of the machined surface having several hardness were studied. Good machined surface having high compressive residual surface stresses can be achieved if cutting tools having large edge radius and small nose radius are used for cutting work materials having high hardness with high depth of cut. The magnitude of edge radius and the hardness of work material also affected the shape of the chip in orthogonal cutting.

• Steel and Composite Structures
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• 제29권5호
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• pp.681-688
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• 2018

In this paper, buckling load of edge stiffened composite plates is assessed. The effect of stiffener edge size, circular hole, and the fiber orientation angle on buckling behavior of composite plates under uni-axial compressive load is investigated. This paper includes two parts as experimental and numerical studies. L-shape composite plates are manufactured in three different layups. Then the buckling loads are experimentally determined. Subsequently, by using the numerical simulation, the size variation effects of stiffener edge and circular cutout on the plate buckling loads are analyzed in five different layups. The results show that cutout size, stiffener edge height and fiber orientation angle have important effects on buckling load. In addition, there is an optimum height for stiffener edge during different conditions.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.2213-2216
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• 2003

In this paper, we propose the face identification method which is robust for lighting based on the feature points method. First of all, the proposed method extracts an edge of facial feature. Then, by the hough transform, it determines ellipse parameters of each facial feature from the extracted edge. Finally, proposed method performs the face identification by using parameters. Even if face image is taken under various lighting condition, it is easy to extract the facial feature edge. Moreover, it is possible to extract a subject even if the object has not appeared enough because this method extracts approximately the parameters by the hough transformation. Therefore, proposed method is robust for the lighting condition compared with conventional method. In order to show the effectiveness of the proposed method, computer simulations are done by using the real images.

• 대한조선학회논문집
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• 제37권1호
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• pp.60-66
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• 2000

고속 프로펠러를 대상으로 캐비테이션 발생 특성에 가장 큰 영향을 미치는 2차원 날개단면의 앞날 형상에 관한 연구를 수행하였다. 앞날 주위의 유동장을 해석하기 위하여 비압축성 RANS(Reynolds Averaged Navier-Stokes)방정식을 유한체적법(FVM)으로 차분하는 수치해석기법을 사용하였다. 또한 패널법을 이용하여 캐비테이션 발생두께를 예측하였다. 예측된 결과들은 실험결과와 비교해서 타당함을 알 수 있었으며, 이 결과를 이용하여 새로운 단면을 설계하였다.

• 대한기계학회논문집
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• 제6권3호
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• pp.232-238
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• 1982

The behavior of corner crack propagation by unidirectional plane bending fatigue was investigated in the butt welded joints of SS41 and SM50 steel plates including an edge through-thickness notch. The properties of fatigue crack propagation were inspected in the weld metal, heat-affected zone, and base metal of the welded joints. Main results obtained are as follows; (1) When a plate with an edge through-thickness notch is loaded by plane bending fatigue in indirection, the 2 variant corner cracks on the upper and lower edge of the plate are initiated and propagated respectively from the notch. (2) In case of a specimen containing a corner crack, it is more reasonable to estimate the crack propagation rate by area of fracture surface than by crack surface length. (3) The rate of fatigue crack propagation becomes faster in the following order; weld metal, heat-affected zone, and base metal. (4) The specimen including reinforcement shape is rapidly failed throughout bond due to effect of its shape when the repeated load exceeds a certain cycle.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.134-139
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• 2002

We have made known the study of shape development of interference device for vehicle noise control. It's primary object greatly attenuate the noise due to transport vehicle by small products installed on the noise barrier edge. Also, it is able to improve the insertion loss of a noise barrier without increasing the height. The present time, we set up a newly manufactured products on the noise barrier edge and testify to it's the performance make use of an experiment and evaluation for the reduction of highway traffic noise. In this paper the frequency characteristic of interference device of noise barriers with attached newly developed products in terms of shape, absorptive material and split panel, are examined using field test at highway.