• 한국CDE학회논문집
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• 제5권2호
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• pp.196-205
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• 2000

This paper proposes a topology-based algorithm for recognizing the passage features using a concept of multi-face hole loop. The Multi-face hole loop is a concetpual hole loop that is formed over several connected faces. A passage feature is recognized in the proposed approach by two multi-face hole loops that constitute its enterance and exit. The algorithm proposed in this paper checks the connectivity of the two multi-face hole loops to recognize passage features. The total number of passage features in a part is calculated from Euler equation and is compared with the number of found passage features to decide when to terminate. To find all multi-face hole loops in a part, this paper proposes an algorithm for finding all combinations of connected faces. The edge convexity is used to judge the validity of multi-face hole loops. By using the algorithm proposed in this paper, the passage features could be recognized effectively. The approach proposed in this paper is illustrated with several example parts.

• International Journal of Ocean Engineering and Technology Speciallssue:Selected Papers
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• 제3권1호
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• pp.40-48
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• 2000

The term "deep holes" is used to describe the machining of holes with a relatively large length to diameter ratio. The main feature of BTA deep hole drilling is the stabilization of cutting force necessary for the self guidance of the drill head. An additional feature is the cutting tool edges that are unsymmetrically placed on the drill head. There is an increasing necessity to predict the hole geometry and other dynamic stability behavior of deep hole drilling guidance. In this study, the effects of BTA deep hole drilling conditions on the hole profile machined piece are analyzed using domain analysis technique. The profile of deep hole drilled work piece is related to cutting speed, feed rate, chip flow, tool wear, and so on. This study deals with the experimental results obtained during the BTA drilling on SM45C, SM55C carbon steels and SCM440 steels under various cutting conditions, and these results are compared with analytical evaluations.aluations.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 하계종합학술대회 논문집(4)
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• pp.359-362
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• 2002

In this paper, we propose a new feature-based text watermarking for the binary text image. The structure of specific characters from preprocessed text image are modified to embed watermark. Watermark message are embedded and detected by the following method; Hole line disconnect using the connectivity of the character containing a hole, Center line shift using the hole area and Differential encoding using difference of flippable score points. Experimental results show that the proposed method is robust to rotation and scaling distortion.

• Journal of Welding and Joining
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• 제16권5호
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• pp.108-118
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• 1998

This study proposes th analysis and evaluation method of time series ultrasonic signal using the chaos feature extraction for ultrasonic pattern recognition. Features extracted from time series data using the chaos time series signal analyze quantitatively weld defects. For this purpose, analysis objective in this study is fractal dimension and Lyapunov exponent. Trajectory changes in the strange attractor indicated that even same type of defects carried substantial difference in chaosity resulting from distance shifts such as 0.5 and 1.0 skip distance. Such differences in chaosity enables the evaluation of unique features of defects in the weld zone. In quantitative chaos feature extraction, feature values of 4.511 and 0.091 in the case of side hole and 4.539 and 0.115 in the case of vertical hole were proposed on the basis of fractal dimension and Lyapunov exponent. Proposed chaos feature extraction in this study can enhances ultrasonic pattern recognition results from defect signals of weld zone such as side hole and vertical hole.

• 한국철도학회논문집
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• 제2권1호
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• pp.38-46
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• 1999

This study proposes the analysis and evaluation method of time series ultrasonic signal using the attractor analysis. Features extracted from time series signal analyze quantitatively characteristics of weld defects. For this purpose, analysis objective in this study is fractal dimension and attractor quadrant feature. Trajectory changes in the attractor indicated a substantial difference in fractal characteristics resulting from distance shifts such as parts of head and flange even though the types of defects are identified. These differences in characteristics of weld defects enables the evaluation of unique characteristics of defects in the weld zone. In quantitative fractal feature extraction, feature values of 3.848 in the case of part of head(crack) and 4.102 in the case of part of web(side hole) and 3.711 in the case of part of flange(crack) were proposed on the basis of fractal dimensions. Proposed attractor feature extraction in this study can enhance the precision rate of ultrasonic evaluation for defect signals of rail weld zone such as side hole and crack.

• Journal of Welding and Joining
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• 제18권5호
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• pp.77-83
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• 2000

This study proposes the analysis and evaluation method of time series ultrasonic signal using the attractor analysis. Features extracted from time series signal analyze quantitatively characteristics of weld defects. For this purpose, analysis objective in this study is fractal dimension and attractor quadrant feature. Trajectory changes in the attractor indicated a substantial difference in fractal characteristics resulting from distance shifts such as parts of head and flange even though the types of defects are identified. These difference in characteristics of weld defects enables the evaluation of unique characteristics of defects in the weld zone. In quantitative fractal feature extraction, feature values of 3.848 in the case of part of head(crack) and 4.102 in the case of part of web(side hole) and 3.711 in the case of part of flange(crack) were proposed on the basis of fractal dimensions. Proposed attractor analysis and DAC in this study can enhance the precision rate of ultrasonic evaluation for defect signals of rail weld zone such as side hole and crack.

• 대한기계학회논문집A
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• 제36권2호
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• pp.195-201
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• 2012

다양한 소비자의 요구에 따라 가공된 제품을 좀더 신속하고 정확하게 측정할 수 있는 공작기계 내 자동계측장치를 적용하는 사례가 급격히 증가하고 있다. 자동 계측으로 가장 많이 활용되는 접촉식 측정 프로브는 주로 공작물의 가공 원점을 설정하고, 정확한 치수 검사를 통한 불량유무 판정 및 보상가공에 많이 활용된다. 따라서 본 연구에서는 기기상 자동계측장치인 접촉식 측정 프로브를 활용하여 가공된 형상을 신속하고 정확하게 측정하는 방법을 연구하였으며 이를 위하여 가장 많이 활용되는 홀 측정 사이클에 대한 매크로 프로그램을 개발하였다. 또한 측정 시 홀의 진원도 오차에 따라 발생할 수 있는 편심량을 시뮬레이션하여 분석하였으며 본 연구의 신뢰성을 높이기 위하여 기기상에서 개발된 홀 측정 매크로 프로그램을 이용하여 홀플레이트에 대한 측정이 이루어졌으며, 진원도 오차에 따른 편심량을 검증하였다.

• 인지과학
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• 제27권3호
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• pp.355-376
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• 2016

이차원 표면에 난 구멍은 이를 둘러싼 물체에 의해 경계 지워진 빈 배경임에도 불구하고, 구멍의 모양은 다른 물체만큼 쉽게 지각된다. 즉, 구멍은 전경-배경 조직화의 깊이-형태 간 연결 관계(depth-shape coupling)를 예외적으로 위반하여, 깊이 상으로는 배경임에도 불구하고 형태를 갖는 준-전경적(quasi-figural) 사례처럼 보인다. 구멍의 준-전경적 속성을 지지하는 연구들은 구멍과 물체의 재인율이 유사하다는 기억 과제 결과에 주로 의존하고 있으므로, 구멍 모양의 기억이 지각적 처리에 기반하고 있는지는 불분명하다. 본 연구는 재인 과제보다 즉각적인 지각 처리를 반영하는 변화탐지 과제를 이용하여, 구멍을 경계 짓는 물체의 안쪽 윤곽선이 시각 작업기억에 어떻게 표상되는지 알아보았다. 이를 위해, 물체 내부에 다른 물체가 중첩된 접합 물체 조건과 구멍이 있는 물체 조건에서 안쪽 윤곽선과 바깥 영역의 색에 대한 변화탐지 수행을 비교하였다. 시각 작업기억의 선행 연구들은 형태나 방향과 같은 물체의 윤곽선 속성(boundary feature)이 표면 속성(surface feature)과 함께 통합되어 하나의 물체로 저장됨을 시사한다. 만일 구멍의 경계선이 구멍을 둘러싼 물체에 지각적으로 할당된다면, 이 경계선과 물체의 표면색이 통합적으로 부호화되는 물체 중심적 처리 이득으로 인해, 구멍 자극 조건에서 접합 자극 조건보다 높은 변화 탐지 수행이 예측되었다. 두 실험의 결과, 구멍 자극 조건의 변화 탐지 수행은 접합 자극 조건과 다르지 않았다. 이는 물체 내부의 윤곽선(구멍의 경계선) 속성이 물체의 표면 속성과 통합적으로 부호화되지 않으며, 구멍을 둘러싼 물체와 독립적으로 처리됨을 시사한다.

• 소성∙가공
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• 제19권5호
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• pp.320-324
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• 2010

Multi-Layer Ceramic Circuit(MLCC) in the face of thousands of fine pitch multi hole is processed. However, the fine pitch multi hole has a size of only a few micrometers. Therefore, in order to curtail the measurement time and reduce error, the image processing measurement method is required. So, we proposed an image processing measurement algorithm which is required to accurately measure the fine pitch multi hole. The proposed algorithm gets image of the fine pitch multi hole, extracts object from the image by morphological process, and extracts the parameters of its position and feature by edge detecting process. In addition, we have used the sub-pixel algorithm to improve accuracy. As a result, the proposed algorithm shows 97% test-retest measurement reliability within 2 ${\mu}m$. We found that the algorithm was wellsuited for measuring the fine pitch multi hole.

• 한국공작기계학회논문집
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• 제12권3호
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• pp.8-16
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• 2003

Monitoring of the drill wear :md hole quality change is conducted during the drilling process. Cutting force measured by tool dynamometer is a evident feature estimating abnormal state of drilling. One major difficulty in using tool dynamometer is that the work-piece must be mounted on the dynamometer, and thus the machining process is disturbed and discontinuous. Acoustic transducer do not disturb the normal machining process and provide a relatively easy way to monitor a machining process for industrial application. for this advantage, AE signal is used to estimate the abnormal fate. In this study vision system is used to detect flank wear tendency and hole quality, there are many formal factors in hole quality decision circularity, cylindricity, straightness, and so of but these are difficult to measure in on-line monitoring. The movement of hole center and increasement of hole diameter is presented to determine hole quality. As the results of this experiment AE RMS signal and measurements by vision system are shorn the similar tendency as abnormal state of drilling.