• The Transactions of the Korean Institute of Power Electronics
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• v.4 no.1
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• pp.66-72
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• 1999

This paper deals with the output characteristics of resonant PWM inverter type X-ray generators connected to different DC power units i.e. a single phase full bridge rectifier, a three phase full bridge rectifier and a power storage unit(PSU). The quality of X-ray beam depends on the pulsating waveforms of DC voltage supplied to the X-ray tube. In a X-ray generator, the waveform of DC output voltage can be affected from affected from harmonic distortion of DC input power. When a tube voltage waveform is distorted, the property of X-ray beam such as reproducibility, linearity and dose can be reduced. Therefore, we compared DC output waveforms and dose with three type of DC power units and show the experimental results in this paper.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.48 no.4
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• pp.94-101
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• 2011

Various kinds of medical imaging devices have been studied to develop periapical radiography. However, there are some problems such as high x-ray exposure rate and pains for patients because of the problems caused by intra-oral sensor based radiography system. In this study, a new concept of periapical radiography, intra oral X-ray tube and detector system, is introduced to solve these problems. This system is made up of miniature X-ray tube based on subminiature thermal electron or cold electron, CMOS based detector, and a body including automatic position and system control devices. In order to confirm the possibility of proposed new concept to periapical radiography, miniature x-ray tube from XOFT corporation is used to develop new x-ray system, and the performance evaluation of this system is performed according to collimator. Also, dental images are compared after acquiring both images from existing system versus new concept of system. As a result, new concept of system showed excellent image. Thus, it is considered that new concept of system will have a significant effect on medical imaging technology.

• Journal of the KSME
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• v.32 no.5
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• pp.410-419
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• 1992

이 글에서는 길이의 정밀 측정에 널리 사용되고 있는 여러 종류의 레이저 간섭계에 대하여 그 작동 원리 및 응용 예를 간략하게 살펴보았다. 아울러, 나노 영역에서의 길이 및 각도를 높은 정확도로 측정할 수 있는 X-선 간섭계의 원리 및 응용에 대하여도 간략히 기술하였는데, 이러한 X-선 간섭계를 이용한 정밀 측정기술은 앞으로도 개발의 여지가 많은 새로운 분야이며, 따라서 그 응용 범위도 점차 널리 확대되리라 예상된다.

• Korean Journal of Optics and Photonics
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• v.3 no.2
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• pp.137-140
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• 1992

레이저 플라즈마에서 방출되는 X-선의 이용이 크게 발전될 것이 예측되나, X-선에 대한 광속의 시준화, beam homogenizing, 광속축소, 광유도 등이 어려워서 예상한 바 큰 발전이 이루어지지 못하고 있다. 이 난제를 해결할 수 있는 가능성이 모세관 광유도광학에서 엿보이기에 여기에 소개하여 광학, 레이저 플라즈마 등을 연구하는 회원들의 관심을 끌고자 한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.9
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• pp.4152-4158
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• 2012

The Stereo X-ray inspection system is designed for effectively providing the additional information of objects than the conventional inspection system that offers only 2D cross-section of objects. We studied the geometric improvement of the stereo X-ray inspection system, the stereo matching algorithm of the single object using the edge and the volume reconstruction method for the inspected object. In this paper, we conduct a matching algorithm to find the correspondences between the images and reconstruct 3-D shapes of real objects using the stereo X-ray images. Also, we apply a new 3D reconstruction algorithm for the discrimination of two objects. For the separation of the overlapping objects, we calculate the vector of the object and divide inner and outer voxel of objects. And for the elimination of the overlapping area, we study the reconstruct 3D shapes using the threshold based Z-axis. The experimental results show that the proposed technique can enhance the accuracy of stereo matching and give more efficient visualization for overlap objects in the restricted environment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.5
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• pp.2298-2304
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• 2012

X-ray fluorescence spectrum analysis method can be applied in many areas, including concentration analysis of RoHS elements and heavy metals etc. and we can get analysis results in a relatively short time. Because X-ray fluorescence spectrum has noises and several artifacts that lowers the accuracy of the analysis. This paper analyzes the characteristics of the noise of the X-ray fluorescence spectrum to increase the accuracy of analysis. X-ray fluorescence spectrum have the characteristics of shot noise (Poisson noise), so the noise size is relatively large in the small signal portion and the noise the size is relatively small in the large part of the signal. Existing methods of analysis and to remove noises is a method for general purposes algorithm. Since these algorithm does not reflect these noise characteristics, we get distorted analysis result. We can design efficient noise remove algorithm based on the accurate noise analysis method, and we expect high accuracy results of the elemental concentration analysis result.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.531-533
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• 2017

본 논문에서는 퍼지 영상처리 기법을 이용하여 손뼈의 X-Ray 영상에서 손뼈의 윤곽선을 추출하는 방법을 제안한다. 제안된 방법에서는 전 처리 단계로써 감마 상관관계를 이용하여 X-Ray 영상에서 손뼈를 제외한 피부층을 제거한다. 피부층이 제거된 영상에서 손뼈를 뚜렷하게 만들기 위해 샤프닝 기법을 사용한다. 샤프닝 기법이 적용된 영상에서 손뼈의 명암대비를 선명하게 하기 위해 사다리꼴 형태의 Fuzzy Stretching 기법을 적용한다. 사다리꼴 형태의 Fuzzy Stretching 기법을 적용한 영상에서 Canny Edge 기법을 적용하여 손뼈의 윤곽선을 추출한다. 제안된 추출 방법을 20개의 실험 영상을 대상으로 실험한 결과, 16개의 실험 영상에서는 손뼈의 윤곽선이 정확히 추출되었고 4개의 실험 영상에서는 손뼈의 윤곽선이 손실된 상태로 추출되었다.

• Applied Microscopy
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• v.38 no.3
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• pp.235-243
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• 2008

A compact soft x-ray microscope operated in the 'water window' wavelength region ($2.3{\sim}4.4nm$) was used for observing cells with nano-scale spatial resolution. To obtain cellular imaging captured with colloidal gold nanoparticles using a compact soft x-ray microscope. The colloidal gold nanoparticles showed higher contrast and lower transmission more than 7 times than that of cellular protein on the soft x-ray wavelength region. The structure and thickness of the cell membrane of the Coscinodiscus oculoides (diatome) and red blood cells were seen clearly. The gold nanoparticles within the HT1080 and MDA-MB 231 cells were seen clearly on the soft x-ray microscopy. The gold nanoparticles were aggregated within vesicles by endocytosis.

• Journal of the Korean Society of Radiology
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• v.15 no.2
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• pp.153-158
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• 2021

X-ray image analysis is a very important field to improve the early diagnosis rate and prediction accuracy of periodontal disease. Research on the development and application of artificial intelligence-based algorithms to improve the quality of such dental X-ray images is being widely conducted worldwide. Thus, the aim of this study was to design a super-resolution algorithm for predicting periodontal disease and to evaluate its applicability in dental X-ray images. The super-resolution algorithm was constructed based on the convolution layer and ReLU, and an image obtained by up-sampling a low-resolution image by 2 times was used as an input data. Also, 1,500 dental X-ray data used for deep learning training were used. Quantitative evaluation of images used root mean square error and structural similarity, which are factors that can measure similarity through comparison of two images. In addition, the recently developed no-reference based natural image quality evaluator and blind/referenceless image spatial quality evaluator were additionally analyzed. According to the results, we confirmed that the average similarity and no-reference-based evaluation values were improved by 1.86 and 2.14 times, respectively, compared to the existing bicubic-based upsampling method when the proposed method was used. In conclusion, the super-resolution algorithm for predicting periodontal disease proved useful in dental X-ray images, and it is expected to be highly applicable in various fields in the future.

• Proceedings of the Ginseng society Conference
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• 1984.09a
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• pp.133-140
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• 1984

인체가 방사선에 의해 손상을 받게 되면, 실제적으로 치료, 회복시킨 수 있는 물질은 아직 발견되지 않았다. 이에 저자는 720R의 X-선을 조사시킨 mice에 Oura 등의 방법에 따라 부분 정제한 인삼 추출물을 투여하여 X-선 손상으로부터의 회복능을 검정하였다. 주사한 인삼 추출물의 용량에 의존적으로 30일간의 생존율이 증가하였다. Saline을 주사한 대조군과 인삼 추출물을 주사한 실험군 사이의 생존율의 차이는, 동물 한 마리당 1.8mg을 투여한 실험에서 조차 통계학적으로 유의성을 보였다. (P<0.001) 550R의 X-선을 조사시킨 mice에 인삼 추출물을 투여하면 적혈구와 혈소판의 양적 회복이 촉진되었다. 또한 인삼 추출물중 열에 안정한 분획이 비장이 비대하여지는 것과 같은 부작용이 없어 방사선의 손상으로부터 보호 효과가 있음을 알았다. 이 분획은 mice뿐만 아니라, 반치사량의 X-선을 조사한 rat, guinea pig와 같은 실험동물에 있어서도 30일간의 생존율이 더 연장되므로서 현저한 효과를 보였다. 혈액상태 특히 혈소판의 양적 회복은 열에 안정한 이 분획에 의해서도 촉진되었다. 열에 안정한 분획을 투여한 mice에 있어서 X-선 조사에 의한 출혈이 방지되는데, 이를 매일 매일의 변에서 잠재혈액을 측정함으로써 정량적으로 관찰하였다. 결론적으로, 인삼 투여로 방사선에 의한 치사율이 감소되는데 이의 기전은 혈소판 생성을 촉진시키며, X-선에 의한 출혈을 감소시키기 때문이다.