• KIPS Transactions on Software and Data Engineering
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• v.12 no.6
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• pp.243-250
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• 2023

Chest X-ray is radiological examination for xeamining the lungs and haert, and is particularly widely used for diagnosing lung disease. Since the quality of these chest X-rays can affect the doctor's diagnosis, the process of evaluating the quality must necessarily go through. This process can involve the subjectivity of radiologists and is manual, so it takes a lot of time and csot. Therefore, in this paper, based on the chest X-ray quality assessment guidelines used in clinical settings, we propose a tool that automates the five quality assessments of artificial shadow, coverage, patient posture, inspiratory level, and permeability. The proposed tool reduces the time and cost required for quality judgment, and can be further utilized in the pre-processing process of selecting high-quality learning data for the development of a learning model for diagnosing chest lesions.

• Journal of the Korean Society of Radiology
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• v.83 no.5
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• pp.1153-1159
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• 2022

Dolichoectasia is an uncommon disorder characterized by the presence of a dilated, elongated, and tortuous cerebral artery. Its main pathologic mechanism is the disruption of the internal elastic lamina. Risk factors for dolichoectasia are advanced age, chronic hypertension, and metabolic disease. It mainly involves the vertebrobasilar vasculature (or "posterior circulation"), but dolichoectasia can also be seen in the anterior circulation, particularly the anterior cerebral artery. There are no reported cases of dolichoectasia involving both anterior and posterior circulation in South Korea. Here we report an unusual case of dolichoectasia involving both anterior and posterior circulation in a young female without any underlying disease on the basis of prominent imaging findings.

• Journal of the Korean earth science society
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• v.36 no.4
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• pp.330-340
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• 2015

For this study, we developed an algorithm to estimate the total amount of clouds using sky image data from the Skyviewer equipped with CCD camera. Total cloud amount is estimated by removing mask areas of RGB (Red Green Blue) images, classifying images according to frequency distribution of GBR (Green Blue Ratio), and extracting cloud pixels from them by deciding RBR (Red Blue Ratio) threshold. Total cloud amount is also estimated by validity checks after removing sunlight area from those classified cloud pixels. In order to verify the accuracy of the algorithm that estimates total cloud amount, the research analyzed Bias, RMSE, and correlation coefficient compared to records of total cloud amount earned by human observation from the Gangwon Regional Meteorological Administration, which is in the closest vicinity of the observation site. The cases are selected four daily data from 0800 LST to 1700 LST for each season. The results of analysis showed that the Bias in total cloud amount estimated by the Skyviewer was an average of -0.8 tenth, and the RMSE was 1.6 tenths, indicating the difference in total cloud amount within 2 tenths. Also, correlation coefficient was very high, marking an average of over 0.91 in all cases, despite the distance between the two observation sites (about 4 km).

• Journal of the Korean earth science society
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• v.34 no.1
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• pp.41-50
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• 2013

To analyze the distribution pattern of flood sediment deposits near the mouth of Chucheoncheon (river), side scan sonar images and seafloor sediment properties were investigated in the offshore area within about 50 m deep in water. Based on the analysis result of the sonar images, the seafloor of the study area is divided into three areas of basement, sandy-mud, and dispersed flood sediment. The colors of sonar images in each area are represented by dark black, light grey, and greyish black, respectively. The sediment composition in the grey black area shows 33.73% of gravel, 62.88% of sand, 3.37% of silt, and 0.02% of clay. On the other hand, the composition of the light grey area is 10.31% of sand, 56.42% of silt, and 33.27% of clay. Especially the sediment of the grey black area contains the considerable amount of burned plant fragments in black color, which could distinctly be differentiated from those in the offshore. The distribution pattern of the flood sediment deposits suggests that the land-originated detrital sediments seem to be transported from the Chucheon river into offshore along the shore rather than transversely. In conclusion, the longshore current of the study area is probably dominant to affect the spatial distribution of bottom features.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.31 no.1
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• pp.8-14
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• 1995

The behaviour of large school of sardine Sardinops melanosticta in and around the set-net were analyzed from sonar image recordings. The survey was conducted at Kishihata set-net in Japan from January 29th to February 22th 1992. The results obtained are summarized as follows ; 1. When large schools of sardine moved along the outside of the set-net. the shape of the school gradually changed, that was the front part extended forward in the direction of movement and the rear part concentrated in the same direction such that the school retained its original shape. 2. When large school of sardine entered the main-net of the set-net. the school was decentralized directly to the slope-net. to the central part. and to the opposite side, and then the fish school was concentrated as it moved directly to the slope-net. 3. When the size of the front part of the fish school enlarged. the maximum recorded moving speeds were 176cm/sec and 277cm/sec for schools inside and outside the set-net, respectively.

• Journal of Biomedical Engineering Research
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• v.25 no.2
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• pp.97-102
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• 2004

We developed an x-ray cone-beam micro computed tomography (micro-CT) system for small-animal imaging. The micro-CT system consists of a 2-D flat-panel x-ray detector with a field-of-view (FOV) of 120${\times}$120 mm2, a micro-focus x-ray source, a scan controller and a parallel image reconstruction system. Imaging performances of the micro-CT system have been evaluated in terms of contrast and spatial resolution. The minimum resolvable contrast has been found to be less than 36 CT numbers at the dose of 95 mGy and the spatial resolution about 14 lp/mm. As small animal imaging results, we present high resolution 3-D images of rat organs including a femur, a heart and vessels. We expected that the developed micro-CT system can be greatly used in biomedical studies using small animals.

• The Optical Journal
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• s.118
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• pp.20-24
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• 2008

폰카메라는 1998년 일본을 시작으로 지금까지 발전하여 왔다. 초기에는 화상통신용 개념으로 시작했지만 디지털카메라가 부각되면서 디지털카메라 대체용으로 폰카메라가 대량생산 되었고 경쟁적인 고화소 경쟁으로 최고 1,400만 화소까지 기획되고 있다. 현재 자동초점 카메라모듈에서 300만 화소 이상이 주류를 이루고 있어 자동초점은 기본 사양이 될 것으로 보인다. 따라서 폰카메라에서의 렌즈도 필름 카메라나 디지털 카메라처럼 actuator가 기본적으로 장착된 제품으로 인식되어 질 것으로 확신한다. 또한 모바일폰의 동영상 기능 강화로 줌 렌즈의 요구는 커질 것으로 보여 2011년 쯤에 보편화가 되지 않을까 기대한다.

• Proceedings of the Korea Multimedia Society Conference
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• 2000.04a
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• pp.149-152
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• 2000

3차원 물체 형상 모델링은 인식에 있어서 중요한 역할을 차지하고 있다. 기존의 픽셀(pixel)기반 영상표현은 물체 고유의 유기적 구조를 반영할 수 없고, 에지(edge)나 기반 물체 표현법은 물체의 자세한 표현이 가능하지만 물체인식을 위해서는 많은 양의 속성들을 만들어내게된다. 따라서 물체인식을 위해서는 물체의 형상특징을 직선적으로 기술할 수 있는 체적소 기반 물체 표현 방법이 필요하다. 본 논문에서는 몇 개의 파리미터를 이용하여 3차원 정보를 효과적으로 얻을 수 있는 superquadric과 이를 기본 단위로 한 CSG(Constructive Solid Geometry) tree를 이용하여 3 차원 물체 형상모델링에 대해서 기술한다.

• Proceedings of the Korea Contents Association Conference
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• 2003.11a
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• pp.253-259
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• 2003

최근 각 이동통신사업별로 기존의 CDMA 방식을 이용하여 IMT-2000의 서비스에 해당되는 대용량 데이터서비스를 제공하고 있다. 그러나 각 사업자 별로 할당된 현재의 주파수대역으로는 영상서비스를 기본으로 하는 대용량 데이터서비스를 제공하기 어려운 상황이며, 새로운 주파수대역의 추가 분배가 필요한 상태이다. 본 논문에서는 ITU-R에서 제시하고 있는 권고안을 기초로 국내 이동통신서비스 확대에 요구되는 추가 스펙트럼 요구량을 산출하였으며, 디지털 이동통신서비스를 위해 필요한 스펙트럼 효율의 정량화 및 추가 소요 주파수 대역을 계산하는 방법을 정량화 하였다.

• Proceedings of the KIEE Conference
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• 2006.11a
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• pp.345-347
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• 2006

신설 선로와 기존 선로와의 계통 연계시 상 배치에 따라 연계 후 발생하는 급격한 영상전류의 증가로 인하여 지락계전기의 동작 같은 계통에 악 영향을 미치는 현상이 일어난다. 이 논문은 송전선로의 연가철탑을 이용한 역상배치 시행여부에 따른 계통 해석과 상시 불평형률을 문경 변전소 신설에 따라 10월 가압 목표로 시공 중인 송전선로의 $1{\pi}$분기와 관련하여 ${\pi}$분기시의 이상적인 송전선로 상 배열을 분석한다.