http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Computed Radiography의 영상특성에 관한 연구
류기현,정재은,Ryu, Ki-Hyun,Jung, Jae-Eun 대한디지털의료영상학회 2008 대한디지털의료영상학회논문지 Vol.10 No.2
Computed radiography(CR) has been widely used in the field of diagnostic radiography since digital X-ray image was introduced. The imaging performance of CR system was studied by analyzing the digital image data of the CR images which are the outcomes of the whole imaging system composed of image plate(IP), laser digitizer, analoge-digital convertor, and a given image processing unit. In this study, we used a conventional CR system made by Agfa. From the flat field image of 150$\times$150 image pixels, signal-to-noise ratio(SNR) was calculated. SNR of the CR image increases in proportion to logarithm value of the X-ray exposure irradiated on the IP. SNR is less than about 6 at the exposure below 0.2mR and is more than 10 at the exposure above 0.54mR. In our study, most of images obtained by the smaller exposures less than 2.0mR can not be readable. In general, the minimum value of the SNR ranges from 3 to 5. We obtained modulation transfer function(MTF) by analyzing the bar pattern image which was made under conditions as follows: X-ray tube potential was 55kVp, the IP exposure was 0.54 mR, and the distance between X-ray source to IP was 2m, where bar pattern was located on the IP. MTF is 23% at 2.5lp/mm spatial frequency. Provided that the MTF of noise equivalent modulation is 10%, the CR system has the limiting spatial resolution of 3.2lp/mm. If the image sharpness is evaluated by the spatial frequency where MTF is 50%. the corresponding spatial frequency is 0.5$\sim$0.75lp/mm. MTFA(Modulation Transfer Function Area) is 1.0lp/mm. Compared with the Fuji CR whose MTFA is 1.1lp/mm, Agfa CR in this study shows almost same MTFA performance.
Ultrastructure of Cymbidium Leaf Tissue Systemically Infected with Odontoglossum Ringspot Virus
류기현,김우갑,박원목,Ryu, Ki-Hyun,Kim, Woo-Kap,Park, Won-Mok Korean Society of Electron Microscopy 1994 Applied microscopy Vol.24 No.3
In ultrathin section of the tissue of odontoglossum ringspot virus (ORSV)-infected Cymbidium goeringii Reichenbach, ORSV particles appeared as bundles of irregular aggregates of various length which were called stacked plates or rounded plates. Virus particles were found in the cytoplasm in electron clear zones and they also found between cell wall and plasma membrane. They mainly clustered in parallel aggregates and sometimes oriented randomly. The X-bodies and paramural bodies were observed near the cell membrane and these contained vacuole-like cavities. The cell wall of infected tissue expanded largely. Some chloroplast in ORSV infected cell was irregular. No virus particle was present in mitochondria, nuclei, vacuoles, vesicles or other organelles. The plasmodesmata slightly enlarged, and virus-associated granules were present around it. 오돈토글로썸 윤문 바이러스(ORSV)에 감염된 한국 자생춘란(Cymbidium goeringii) 초박절편의 전자현미경 관찰에서 ORSV 입자들은 집적되거나 환형상 평면구조로 다양한 크기의 불규칙적인 응집된 다발상들이 관찰되었다. 바이러스 입자들은 원형질체에서 다수 존재하였고, 세포벽과 원형질막 사이에서도 존재하였으며, 이들은 주로 응집된 평행상과 불규칙적인 산재된 형태로 관찰되었다. X-체 및 paramural body는 원형질막 주변에 존재하였고 액포와 유사한 낭상 구조체에 싸여있었다. 바이러스에 감염된 조직의 세포벽은 확장되어 있었다. ORSV에 감염된 세포내 엽록체는 불규칙적인 모습을 보였다. 미토콘드리아, 핵, 액포, 소포 및 기타 세포내 소기관들내에서는 바이러스 입자를 볼 수 없었다. 원형질연락사(plasmodesmata)는 다소 확장되고, 바이러스 입자들이 이들 원형질연락사 주변에 존재하였다.
네트워크 기반 대용량 데이터 분석도구 : 마이크로어레이 데이터
류기현(Ki-Hyun Ryu),박희창(Hee-Chang Park) 한국정보과학회 영남지부 2005 한국정보과학회 영남지부 학술발표논문집 Vol.13 No.1
마이 크로어레이(microarray) 데이터는 다양하고 복잡한 구조의 데이터로 이루어져 있어, 효과적으로 데이터에 접근하고 처리하기 위해 데이터베이스에 저장하는 것이 일반적이다. 그러나 데이터베이스마다 데이터를 저장하는 형식과 구조가 다르고, 데이터베이스의 미개발로 인해 데이터의 저장이 파일로 이루어져 있을 경우에 다양한 형식이 존재하기 때문에 데이터를 분석하고 처리하는데 많은 어려움이 있다. 기존의 마이크로어레이 분석도구들은 복잡한 사용법과 운영체제에 독립적이지 않아 분석 도구를 선택함에 있어서 데이터 형태 이외에도 별도의 사전지식이 필요하고 운영체제를 고려해야 하는 어려움이 있다. 본 논문에서는 유전자 마이크로어레이 데이터로부터 유용한 정보를 얻기 위한 분석도구를 설계하고 구현하였다. 유전자 마이크로어레이 데이터 분석도구를 선택 할 때 고려해야 했던 데이터 형태, 운영체제 그리고 분석도구를 사용하기 전에 알아야하는 전문지식이나 별도의 교육 없이도 효율적으로 데이터를 분석할 수 있도록 하였다.
류기현 ( Ki Hyun Ryu ),허규찬 ( Kyu Chan Huh ) 대한장연구학회 2010 Intestinal Research Vol.8 No.2
Clinicians are frequently challenged to interpret gastrointestinal symptoms in patients with inflammatory disease (IBD). Irritable bowel syndrome (IBS)-like symptoms are common in patients with IBD and the underlying mechanism is likely to be active or occult inflammation of the bowel rather than co-existing IBS. Biopsychosocial construct and mucosal inflammation, stress, alteration of the hypothalamic-pituitary-adrenal axis, and autonomic dysregulation are contributing factors to IBD-IBS. In particular, low-grade inflammation and immune activation are recent topics regarding the underlying mechanism. Some authors have claimed that inflammation could be a common pathophysiologic factor, in which IBS and IBD might represent the two ends of a wide spectrum of chronic inflammatory conditions. Mast cells, enteroendocrine cells, T cells, and B cells are main effector cells in immune responses. Differentiating IBS symptoms from exacerbation of IBD is important, thus preventing the use of excessive IBD medications, with the potential side effects, or narcotics. Medical treatments with anti-diarrheals, anti-spasmodics, anti-depressants, and anxiolytics can be helpful. However, abuse can lead to medication-dependency and bring about side effects. A healthy, balanced lifestyle, including diet and exercise, should be endorsed. (Intest Res 2010;8:95-105)