• Journal of the Korean Society for Nondestructive Testing
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• v.29 no.1
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• pp.36-42
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• 2009

We have developed software for converting the volumetric voxel data obtained from X-ray computed tomography(CT) into computer-aided design(CAD) data. The developed software can used for non-destructive testing and evaluation, reverse engineering, and rapid prototyping, etc. The main algorithms employed in the software are image reconstruction, volume rendering, segmentation, and mesh data generation. The feasibility of the developed software is demonstrated with the CT data of human maxilla and mandible bones.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.10
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• pp.26-34
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• 2000

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.3
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• pp.443-450
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• 1989

A digital testing method for measurement of radial error motions of a spindle is investigated with special emphasis on developing a computer-aided in-situ inspection for machine tool manufacturing. The method utilizes three non-contact type probes and an optical encoder, based on a special computational algorithm to eliminate undesirable offset and roundness errors of the master spindle. Details of the design of hardware and software required to realize the testing method are described. Finally, advantages and limitations of the method are discussed with several test results.

• Journal of the KSME
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• v.34 no.3
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• pp.177-184
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• 1994

이 글에서는 기하공차의 기본적인 개념들에 대한 설명과 삼차원측정기 응용소프트웨어에서 기하 공차를 평가하기 위한 수학적인 방법들에 대해 소개하였다. 최소영역법은 ISO규격에 의한 공차 평가법이란 점에서 근래의 연구의 대부분을 차지하고 있으나 표준적인 알고리즘이라 할 수 있는 방법은 아직 발표되지 않고 있으며 실용적인 소프트웨어의 경우 최소자승법을 근간으로 하고 있는 실정이다. 최근에는 이러한 형상추출과 기하공차평가를 포함하는 좌표식 측정기 술(coordinate metrology)이 컴퓨터통합생산(computer integrated manufacturing)시스템 구축에 있어서 아킬레스건이라 할 수 있는 컴퓨터원용검사(computer aided quality control)의 핵심적인 기술로 인식되어 선진국에서는 이미 표준기술을 확립하고자 하는 목적으로 체계적인 지원하에 연구를 수행하고 있다. 그러므로 국내에서도 품질보증에 의한 제조업 분야의 생산성 제고를 위 하여 좌표식 측정기술에 대한 연구와 투자가 시급하며 국내의 표준기술 확립이 절실히 요청되고 있다하겠다.

• Transactions of the Korean Society of Automotive Engineers
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• v.3 no.6
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• pp.199-211
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• 1995

As international market pressures increase, product life cycles are becoming shorter at same time requirements for productivity and flexibility are becoming higher. Major improvement in robot programming user interface is central to increasing productivity and flexibility for automatic manufacturing environments. New computer technologies have the potential to accomplish this improvement. In this study we have developed a system which proves that interactive computer graphics and geometric modeling have matured to the point where their artful application into an integrated system can rsult in radically new and powerful user interface for robot programming. With the graphic user interface environment the system efficiently utilizes the existing CAD data and gemetric modeling techniques for off-line programming and simulations. Also the system successfully generates robot control programs performing the desired tasks given through off-line programming.

• Journal of the Microelectronics and Packaging Society
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• v.30 no.4
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• pp.69-78
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• 2023

With the rapid growth of artificial intelligence, the demand for semiconductors is enormously increasing everywhere. To ensure the manufacturing quality and quantity simultaneously, the importance of automatic defect detection during the packaging process has been re-visited by adapting various deep learning-based methodologies into automatic packaging defect inspection. Deep learning (DL) models require a large amount of data for training, but due to the nature of the semiconductor industry where security is important, sharing and labeling of relevant data is challenging, making it difficult for model training. In this study, we propose a new framework for securing sufficient data for DL models with fewer computing resources through a divide-and-conquer approach. The proposed method divides high-resolution images into pre-defined sub-regions and assigns conditional labels to each region, then trains individual sub-regions and boundaries with boundary loss inducing the globally coherent and seamless images. Afterwards, full-size image is reconstructed by combining divided sub-regions. The experimental results show that the images obtained through this research have high efficiency, consistency, quality, and generality.

• Journal of Chest Surgery
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• v.43 no.6
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• pp.648-654
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• 2010

Background: This study assessed the early results of endovascular repair of acute type B aortic dissection and the aortic wall changes following endovascular repair. Material and Method: From July 2008 to May 2009, the preoperative and follow-up computed tomography (CT) scans of 5 patients with acute type B aortic dissection were evaluated, and these patients had underwent stent graft implantation within 13 days of the onset of dissection (mean: 7 days; range: 3~13). The whole lumen (WL), true lumen (TL) and false lumen (FL) diameters were measured at the proximal (p), middle (m) and distal (d) third of the descending thoracic aorta. Result: The study included four men and one woman with an average age of $59.4{\pm}20.1$ years (age range: 37~79 years). The follow-up CT was performed and evaluated at 7 days and 6 months. The primary tear was completely sealed in all the patients. No paraplegia, paresis or peripheral ischemia occurred and none of the patients died. No endoleaks developed in any of the patients during follow-up. The TL diameters increased from 20.4 to 33.5 mm in the proximal third (p/3), from 19.5 to 29.8 mm in the middle third (m/3) and from 15.2 to 23.5 mm in the distal third (d/3). The FL diameters decreased from 18.7 to 0 mm in the p/3, from 15.4 to 0 mm in the m/3 and from 21.4 to 8.7 mm in the d/3. The changes in the TL diameter were statistically significant in the middle and distal aorta, and those changes in the FL diameter were not statistically significant. There was a decrease in the WL after repair, but this was not statistically Significant. In three patients, the false lumen disappeared completely on follow-up CT at 6 months. Two patients had patent false lumens and no thrombosis. Conclusion: The early results showed that endovascular repair was effective in treating acute type B aortic dissection, and endovascular repair promoted positive aortic wall changes.