• Journal of the Korea Society of Computer and Information
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• v.12 no.1 s.45
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• pp.67-72
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• 2007

In this paper, we present a construction method using perspective model which allows for the representation of the motion of a planar surface under perspective projection. The motion parameters are obtained by minimizing a disparity measure between the region in the current frame and the mapped region in the previous frame. The frames are constructed with dynamic panoramic image using a fixed reference or a time varying reference. By experiment, panoramic image proposed in this paper represents contents more efficiently than static image or video, and has a high volume reduction ratio.

• Proceedings of the Korean Information Science Society Conference
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• 2008.06c
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• pp.468-471
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• 2008

이 논문은 응급상황을 인식하기 위하여 어안렌즈를 통해 획득된 영상을 이용하여 기절 동작을 인식하는 방법을 제안한다. 거실의 천장 중앙에 위치한 어안렌즈(fish-eye lens)를 장착한 카메라로부터 화각이 170인 RGB 컬러 모델의 어안 영상을 입력 받은 뒤, 가우시안 혼합 모델 기반의 적응적 배경 모델링 방법을 이용하여 동적으로 배경 영상을 갱신한다. 입력 영상의 평균 밝기를 구하고 평균 밝기가 급격하게 변화하지 않도록 영상 픽셀을 보정한 뒤, 입력 영상과 배경 영상과 차이가 큰 픽셀을 찾음으로써 움직이는 객체를 추출하였다. 그리고 연결되어 있는 전경 픽셀 영역들의 외곽점들을 추적하여 타원으로 매핑하고 움직이는 객체 영역의 형태를 단순화하였다. 이 타원을 추적하면서 어안 렌즈 영상을 투시 영상으로 변환한 다음 타원의 크기 변화, 위치 변화, 이동 속도 정보를 추출하여 이동과 정지 및 움직임이 기절동작과 유사한지를 판단하도록 하였다. 본 논문에서는 실험자로 하여금 기절동작, 걷기 동작, 앉기 동작 등 여러 동작을 취하게 하고 기절 동작 인식을 실험하였다. 실험 결과 어안 렌즈 영상을 그대로 사용하는 것보다 투시 영상으로 변환하여 타원의 크기변화, 위치변화, 이동속도 정보를 이용하는 것이 높은 인식률을 보였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.12
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• pp.8649-8653
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• 2015

A number of video indexing and retrieval algorithms have been proposed to manage large video databases efficiently. The video similarity measure is one of most important technical factor for video content management system. In this paper, we propose the luminance characteristics model to measure the video similarity efficiently. Most algorithms for video indexing have been commonly used histograms, edges, or motion features, whereas in this paper, the proposed algorithm is employed an efficient similarity measure using the luminance projection. To index the video sequences effectively and to reduce the computational complexity, we calculate video similarity using the key frames extracted by the cumulative measure, and compare the set of key frames using the modified Hausdorff distance. Experimental results show that the proposed luminance projection model yields the remarkable improved accuracy and performance than the conventional algorithm such as the histogram comparison method, with the low computational complexity.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.5
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• pp.497-503
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• 2014

Minimally invasive intramedullary nail insertion or plate osteosynthesis has shown good results for the treatment of long bone fractures. However, directly seeing the fracture site is impossible; surgeons can only confirm bone fragments through a fluoroscopic imaging system. The narrow field of view of the equipment causes malalignment of the fracture reduction, and radiation exposure to medical staff is inevitable. This paper suggests two methods to solve these problems: surgical navigation using 3D models reconstructed from computed tomography (CT) images to show the real positions of bone fragments and estimating the rotational angle of proximal bone fragments from 2D fluoroscopic images. The suggested methods were implemented using open-source code or software and evaluated using a model bone. The registration error was about 2 mm with surgical navigation, and the rotation estimation software could discern differences of $2.5^{\circ}$ within a range of $15^{\circ}$ through a comparison with the image of a normal bone.

• Journal of Chest Surgery
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• v.35 no.1
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• pp.60-63
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• 2002

Edwards Duromedics mechanical valve was introduced into clinical use in 1982 and is still being used today after several modifications. Valve-related complications after mechanical valve replacement are thiombo-embolism, endocarditis, valve malfunction, valve leaflet escape and fracture. Incidence of valve leaflet escape is very low. A 40 year-old male patient who had undergone mitral replacement with a 31mm Edwards Duromedics mechanical valve(model

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.134-135
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• 2017

태양광 패널 등가모델을 결합한 태양광 발전 패널 모의 장치(SAS)는 정확도 면에서 많은 장점이 있다. 특히 SAS에서 사용되는 등가회로 모델은 주변 환경에 맞게 빠르게 변하는 I-V 출력특성을 추출하며, 추출시간이 짧다. 이러한 방법을 이용하려면 제어기를 주목해야하는데, 보통 전압 또는 전류 제어기 하나만 사용한다. 하지만 Fill factor가 높은 패널인 경우, 전압 또는 전류제어기 하나만 사용하여서는 제어가 잘 되지 않기 때문에 본 논문에서는 전압과 전류제어기 모두 사용하되, 필요에 따라 스위칭 하여 사용하는 하이브리드 제어기법을 제안한다. 이러한 기법을 통하여 모두 제어가 가능한 기법을 제안한다.

• Journal of the Korea Society of Computer and Information
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• v.13 no.4
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• pp.97-103
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• 2008

This study is to present a fainting motion recognizing method by using fish-eye lens images to sense emergency situations. The camera with fish-eye lens located at the center of the ceiling of the living room sends images, and then the foreground pixels are extracted by means of the adaptive background modeling method based on the Gaussian complex model, which is followed by tracing of outer points in the foreground pixel area and the elliptical mapping. During the elliptical tracing, the fish-eye lens images are converted to fluoroscope images. the size and location changes, and moving speed information are extracted to judge whether the movement, pause, and motion are similar to fainting motion. The results show that compared to using fish-eye lens image, extraction of the size and location changes. and moving speed by means of the conversed fluoroscope images has good recognition rates.

• Journal of the Korean Society of Radiology
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• v.16 no.5
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• pp.559-565
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• 2022

In this study, we intend to develop a granulation tissue formation model. As a pilot experiment, a contrast agent was injected into the pylorus in 3 rats, the normal pylorus lumen size was confirmed, and a stent was placed. Stent migration was confirmed in to the duodenum within 1 week. In this experiment, stent was sutured and fixed to induce granulation tissue formation after gastrostomy under a fluoroscopic guidance. Twenty rats were divided into Healthy Group / Gastrostomy Group. After anesthesia of the Gastrostomy Group, an abdominal incision was performed, and gastrostomy was performed under a fluoroscopic guidance, and a stent was placed into the pylorus. In order to prevent stent migration due to peristalsis, suture between the pylorus and the proximal end of the stent was performed. Postoperative behavior and weight changes were monitored daily. Four weeks after surgery, gastrointestinal fluoroscopy imaging was performed and rats were sacrifices. To evaluate the degree of granulation formation, the stent was sectioned transversely. Gastrostomy group was statistically significantly higher than Healthy Group in granulation area ratio (all p<.001). In conclusion, it is considered that the level of tissue overgrowth formation for preclinical evaluation of the pylorus stricture model through gastrostomy is appropriate as a research evaluation tool.

• Journal of the Korean Society of Radiology
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• v.14 no.4
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• pp.439-445
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• 2020

The purpose of this study was to investigate the feasibility of stent placement and the evaluation of tissue hyperplasia caused by bare metallic stent placement in a mouse colon model. In a pilot study, C57BL/6 mouse were used to verify diameter of colon. Mean diameter size was 4.05 mm. Twenty C57BL/6 mice were divided into two groups to assess differing stent diameters (Group A, 5 mm diameter; Group B. Group B, 4 mm diameter). Follow-up, 1-week fluoroscopic imaging, 4-week endoscopic imaging were obtained. Mice were sacrificed 4-week after stent placement. Microscopic findings were evaluated. Stent placement was technically successful except one mouse in Group A. Data from the mouse was omitted. During follow-up, five mice in Group A died within 7 days after stent placement, and one stent in Group B was migrated into the rectum. The incidence of stent-related complication was 60% and 10% between group A and Group B, respectively. Gross and Endoscopic findings showed tissue hyperplasia through the mesh, and all the stents had become incorporated into the wall of the colon. Microscopic findings were no statistically significant difference. colonic stent placement was technically feasible, and stent-induced tissue hyperplasia was evident in a mouse model. With stent large size, there was the highest incidence of colon perforation.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2003.11b
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• pp.68-69
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• 2003

본 연구에서는 광역적 도시경관을 파악하기 위하여 수치표고모델과 토지이용 데이터를 이용한 CG화상을 작성하고 경관을 유형화하였다. 또한 각 유형의 시점장에서 도시중심에 위치한 봉의산을 시대상으로 하는 가시권 분석을 실시하였다. 춘천시의 도시경관은 3개 유형으로 분류되었다. 유형1은 개발제한구역 중심의 경관, 유형2는 녹지 중심의 경관, 그리고 유형3은 시가지와 수역을 중심으로 한 경관특성을 나타내었다. 가시권 분석의 결과, 유형1은 수역, 유형2와 유형3은 개발제한구역에서 피시빈도가 높았다. 특히. 시가지와 인접한 의암호가 경관상 중요한 곳으로 분석되었다. 또한 토지이용에서 개발제한구역이 경관상 중요한 곳에 분포하여, 개발제한구역의 해제 정도에 따라 대상지의 도시경관이 영향을 받게 될 것으로 사료된다.