효율적인 크기조절 비디오 트랜스코딩을 위한 움직임 벡터 재 산출에 관한 연구

이규찬(Kyuchan Lee),손채봉(Chaebong Sohn),오승준(Seoung-Jun Oh),안창범(Changbeom Ahn) 한국정보과학회 2004 한국정보과학회 학술발표논문집 Vol.31 No.2Ⅲ

본 논문은 움직임 벡터 재 산출 방법에 있어서 제한된 영역 내의 움직임 벡터 재 탐색 과정을 보다 효율적으로 운용함으로써 기존의 방법보다 빠르게 동작하는 크기조절 트랜스코딩 방법을 제안한다. 기존의 크기조절 비디오 트랜스코딩은 크기 조절된 비디오의 정형화된 재 산출 과정을 통해 움직임 벡터를 구하고, 화질 열화의 최소화를 위해 재 산출된 움직임 벡터를 제한된 탐색 영역 내 과정은 많은 계산이 요구되어 속도 저하의 원인이 되며, 비디오의 특성에 따라 움직임 벡터 재 탐색 과정이 불필요한 경우가 발생한다. 따라서, 움직임이 없는 비디오에 대해서는 움직임 벡터 재 탐색 과정을 수행하지 않음으로써 트랜스코딩 과정의 수행 속도를 개선하고, 움직임이 많은 프레임에 대해서는 움직임 벡터 재 탐색을 수행하여 화질 열화를 최소화하는 방법을 제안한다. 제안된 방법을 적용하였을 때, 움직임이 적은 비디오일수록 화질 열화 없이 트랜스코딩 속도가 약 15%의 향상된 성능을 얻었다.

Ⅰ, Ⅱ기 악성 림프종 환자의 방사선 치료 성적

이규찬 (Kyuchan Lee),김철용 (Chul Yong Kim),최명선 (Myung Sun CHoi) 대한방사선종양학회 1993 Radiation Oncology Journal Vol.11 No.1

A retrospective analysis was done for 69 patients with stage Ⅰ and Ⅱ non-Hodgkin's lymphoma who were treated form May 1981 to December 1990, in the Department of Radiadtion Oncology, Korea University Hospital. We used Ann Arbor Staging system and working Formulation for histological classification. Forty-three patients (43/69, 62.3%) were Stage Ⅰ and 26 patients (26/69, 37.7%) were stage Ⅱ, and B symptom was found in 10.1% (7/69). Nodal lymphoma was 21.7% (15/69); 14 patients with supradiaphragmatic disease and 1 patient with infradiaphragmatic disease. Extranodal lymphoma was 78.3% (54/69); 64.8% (35/54) for head and neck, 25.9% (14/54) for gastrointestinal tract. Histologically, low grade consists of 8.7% (6/69), intermediate grade 84.2% (56/69), high grade 10.1% (7/69), and diffuse large cell type was the most frequent form with 36 patients (36/69, 52.2%). Eighteen patients (26.1%) were treated with radiation therapy alone, 20 patients (29.0%) with radiation therapy combined with chemotherapy, 15 patients (21.7%) with radiation therapy combined with surgery and chemotherapy. Median survival duration was 28 months, and the range of survival time was form 1 month to 134 months, overall five-year survival rate for Stage Ⅰ and Ⅱ disease was 54.2%, with 64.5% for Stage Ⅰ and 37.1% for Stage Ⅱ, For nodal lymphoma, 5-year survival rate was 45.9%, and 56.5% for extranodal lymphoma; 60.6% for head and neck, 52.9% for GI track primary disease. Local control rate for all patients was 88.4% (61/69), with 80% (12/15) for nodal lymphoma and 90.7% (49/54) for extranodal lymphoma. The total failure rate was 34.8% (24/69). Five of 24 (20.8%) patients who were failed developed local failure only, 12.5% (3/24) local failure with distant failure, and distant failure only were found in 66.7% (16/24). Between nodal lymphoma and extranodal lymphoma, there was no significant survival difference, but extranodal lymphoma showed higher incidence.

동적신장검사에서 저선량을 사용한 신장검사의 재현성 평가

이재상,이규찬,이승환,배성복,박종엽,Lee, Jaesang,Lee, Kyuchan,Lee, Seunghwan,Bae, Seongbok,Park, Jongyeop 대한핵의학기술학회 2016 핵의학 기술 Vol.20 No.1

동적신장검사는 신장기능을 영상화하는 대표적인 방법이다. 동적신장검사에서 저선량 방사성의약품의 사용으로 기존 동적신장검사와 저선량을 사용한 신장검사의 비교를 통한 동적신장검사의 재현성을 평가해 보기로 했다. 본 비교실험을 통해 재현성이 우수할 경우 환자에 투여하는 방사선량을 줄인 동적신장검사법을 활용하고 환자의 피폭을 줄이고자 한다. 감마카메라 장비로는 Orbiter, SymbiaE (Siemens, Germany)를 사용하였고, 2013년 1월부터 2014년 2월까지 370 Mbq (10mCi)을 사용한 환자와 동일 환자 중 2014년 3월부터 2015년 7월까지 185 Mbq (5 mCi)을 사용한 환자를 대상으로 $^{99m}Tc-DTPA$사용 검사 21명과 $^{99m}Tc-MAG_3$사용 검사 20명 총 41명을 대상으로 데이터를 선별하였다. 결과 영상의 Renogram에서 Peak 지점의 프레임을 선택하여 신장의 관심영역과 배후방사능의 관심영역을 설정하고 K/B ratio를 구하여 비교하였다. $^{99m}Tc-DTPA$를 사용한 검사에서 370 Mbq을 사용하였을 때의 K/B ratio는 평균 $5.67{\pm}0.8$이었고, 185 Mbq을 사용하였을 때는 평균 $5.62{\pm}0.87$로 큰 차이를 보이지 않았다. $^{99m}Tc-MAG_3$를 사용한 검사에서도 신장/배후방사능 비는 370 Mbq을 사용 시 평균 $14.95{\pm}2.58$과 185 Mbq을 사용 시 평균 $14.56{\pm}2.02$로 큰 차이를 보이지 않았다. Paired sample t-test결과 p-value는 $^{99m}Tc-DTPA$ 0.566, $^{99m}Tc-MAG_3$ 0.363로 같은 비교집단 간 차이점이 없음을 확인하였다. 동일 환자를 대상으로 선량을 370 Mbq에서 185 Mbq로 줄였을 때의 동적신장검사의 재현성은 우수한 것으로 확인 되었다. 저선량 동적신장검사는 기존 감마카메라의 성능 개선 없이 재현성이 우수한 결과를 얻을 수 있고 환자의 피폭 또한 줄일 수 있을 것으로 사료된다. Purpose Dynamic kidney scan is a typical imaging technique that visualizes kidney function. Reproducibility of dynamic kidney scans has been evaluated by comparing low-dose kidney scans with low-dose radiopharmaceutical and standard dynamic kidney scan. With this comparative study, if reproducibility is superb, the dynamic kidney scan method with reduced radioactivity to patients is to be utilized and radiation exposure to patient is to be reduced. Materials and Methods For gamma camera, Orbiter, SymbiaE (Siemens, Germany) was used. Among patients who had used 370 Mbq (10 mCi) from January of 2013 to February 2014 and other patients who had used 185 Mbq (5 mCi) from March of 2014 to July of 2015 with identical condition, 21 subjects using DTPA and 20 subjects using $MAG_3$, 41 subjects in total, had been selected as subjects for data. From renogram of the result image, frame of the peak point was selected. Then, region of interest of kidney and background had been selected and Kidney to Background Ratio has been calculated for comparison. Results In tests using DTPA, kidney to background ratio when using 370 Mbq was $5.67{\pm}0.8$ at average while it was $5.62{\pm}0.87$ when using 185 Mbq, which didn't show much difference. Also in the tests using $MAG_3$, kidney to background ratio when using 370 Mbq was $14.95{\pm}2.58$ at average and $14.56{\pm}2.02$ in 185 Mbq, which neither showed much difference. In paired sample t-test, p-value was 0.566 in DTPA and 0.363 in $MAG_3$, which confirmed that there was no difference between the groups. Conclusion In identical patients, when dose was decreased from 370 Mbq to 185 Mbq, reproducibility of dynamic kidney scan was proven to be excellent. Low-dose Dynamic kidney scan can achieve results with fine reproducibility without improvement in performance of gamma camera and is expected to reduce radiation exposure to patient.

Development of 500kW Tidal Current Energy Converter and Uldolmok Field Test

심우승(Sim, Wooseung),최익흥(Choe, Ickhung),이규찬(Lee, Kyuchan),김해욱(Kim, Haiwook),배종국(Bae, Jonggug),민계식(Min, Kehsik) 한국신재생에너지학회 2011 한국신재생에너지학회 학술대회논문집 Vol.2011 No.11

Hyundai Heavy Industries has developed a tidal current energy converter utilizing the accumulated technology as the world largest constructor for ship and offshore structures. The model has two sets of turbines in both ends in order to utilize the bi-directional current flows in flood and ebb tide. The torque produced by turbine in tidal current is directly delivered to generator along the horizontal axis, in which the turbine, gear, generator, gear and turbine are connected successively. The manufactured model for field test has the turbine diameter of 5 meters to produce the maximum power of 500kW at maximum current speed of 5m/s. The technical verification of tidal power converter was performed by means of small scale model test in towing tank as well as field test at the Strait of Uldolmok located in Jindo of Jeollanamdo province. Field test was performed by mounting the tidal current converter on the SEP(Self Elevating Platform) which could lower the 4 vertical legs on the seabed and could elevate platform over the water surface using the hydraulic power for itself. The field test performed for a month shows that power output is similar or larger compared with the expected one in design stage. This paper presents the development of tidal current energy converter and real sea field test by Hyundai Heavy Industries. This project has finished successfully and provided the technical advance toward commercial services for tidal current power generation in the south-west region in Korea.

1MW(500kW×2)급 조류력 발전시스템의 복합재료 터빈 강도 설계 및 평가

박천진(Cheonjin Park),유승재(Seungjae Yoo),신형철(Hyungcheol Shin),최익홍(Ickhung Choi),이규찬(Kyuchan Lee),곽성효(Sunghyo Kwak),김해욱(Haiwook Kim) 한국신재생에너지학회 2012 한국신재생에너지학회 학술대회논문집 Vol.2012 No.11