http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : June Tak Rhee (검색결과 8 건)
- 무료
- 기관 내 무료
- 유료
-
Rhee,June-Tak 建國大學校基礎科學硏究所 1995 理學論集 Vol.20 No.-
BNL(미국 부르크헤이븐 국립가속연구소)와 CERN(유럽공동입자연구소)에서 상대론적 중이온 충돌, 특히 산소와 황에 의한 상호작용(핵자당에너지 14.6, 60 그리고 200GeV)으로부터 다중 강입자 산출에서 "상대적 엔트로피" R이라고 하는 새로운 특성적량이 연구되었다. 더욱이 슈도래피디티 윈도우 갭과 갭이 없는 "상호 인포메이션" I??을 도입하였다. 이러한 방법에 의해서 충돌축에 대하여 전방과 후방의 반구에서 만들어진 강입자 사이의 상관관계가 상호 인포메이션 I??을 이용하여 분석되었다. 전 페이스 공간과 ??<??의 대칭적인 슈도래피디티 윈도우에서 R값은 에너지에 민감하지 않았다. R값은 윈도우 사이즈에 따라 증가하였고 급격히 포화상태에 도달했다. I??(갭이 없을 때)은 빔(Beam)에너지에 따라 증가하고 반면에 I??(갭이 있을 때)은 에너지에 따라 감소하였다. 이 결과는 Lund Monte Carlo 모델 FRITIOF와 잘 일치되었다. From the multihadron production in relativistic heavy ion collisions, especially oxygen and sulphur induced interaction(at 14.6, 60 and 200 GeV per nucleon) from BNL and CERN, a new characteristic quantity called "relative entropy" R is investigated. More-over we employed "mutual information" I?? with and without a pseudorapidity window gap. By means of these, correlations between hadrons produced in the Forward and Back-ward hemispheres with respect to the collision axis have been analyzed using the mutual information. I?? It is found that R both in full phase space and in different symmetric pesudorapidity windows ??<?? is insensitive to energy. R increases with the scaled win-dow size ??=??/?? and rapidly reaches saturation. I??(without gap) increases with beam energy while I??(with gap) decreases with energy. The results are in good agreement with the Lund Monte Carlo model FRITIOF.
-
상대론적 고에너지에서 원자핵-원자핵 충돌시 발생되어진 입자들과 전-후방 상관관계
이준택 ( June Tak Rhee ) 건국대학교 기초과학연구소 1995 理學論集 Vol.20 No.-
BNL(미국 부르크헤이븐 국립가속연구소)와 CERN(유럽공동입자연구소)에서 상대론적 중이온 충돌, 특히 산소와 황에 의한 상호작용(핵자당에너지 14.6, 60 그리고 200 GeV)으로부터 다중 강입자 산출에서 "상대적 엔트로피" R이라고 하는 새로운 특성적량이 연구되었다. 더욱이 슈도래피디티 윈도우 갭과 갭이 없는 "상호 인포메이션" I(r)을 도입하였다. 이러한 방법에 의해서 충돌축에 대하여 전방과 후방의 반구에서 만들어진 강입자 사이의 상관관계가 상호 인포메이션 I(r)을 이용하여 분석되었다. 전 페이스 공간과 |η| < η(c)의 대칭적인 슈도래피디티 윈도우에서 R값은 에너지에 민감하지 않았다. R 값은 윈도우 사이즈에 따라 증가하였고 급격히 포화상태에 도달했다. I(r)(갭이 없을 때)은 빔(Beam) 에너지에 따라 증기하고 반면에 I(r)(갭이 있을 때)은 에너지에 따라 감소하였다 이 결과는 Lund Monte Carlo 모델 FRITIOF와 잘 일치되었다. From the multihadron production in relativistic heavy ion collisions, especially oxygen and sulphur induced interaction(at 14.6, 60 and 200 GeV per nucleon) from BNL and CERN, a new characteristic quantity called "relative entropy" R is investigated. More-over we employed "mutual information" I, with and without a pesudorapidity window gap. By means of these, correlations between hadrons produced in the Forward and Back-ward hemispheres with respect to the collision axis have been analyzed using the mutual information I(r). It is found that R both in full phase space and in different symmetric pseudorapidity windows |η|< η(c) is insensitive to energy. R increases with the scaled win-dow size ξ=η(c)/ η(max) and rapidly reaches saturation. I(r)(without gap) increases with beam energy while I(r)(with gap) decreases with energy. The results are in good agreement with the Lund Monte Carlo model FRITIOF.
-
이제근(Je-Keun Rhee),정제균(Je-Gun Joung),오석준(S. June O),장병탁(Byoung-Tak Zhang) 한국정보과학회 2004 한국정보과학회 학술발표논문집 Vol.31 No.1B
유전자 발현은 다양한 전사 인자들의 상호 작용에 의해서 조절되어진다. 이러한 전사 인자들에 존재하는 모티프는 직접적으로 조절 작용을 위한 기능을 수행한다. 또한 대부분의 경우에서 여러 모티프가 함께 유전자 발현 기작을 위하여 조절 작용을 한다. 따라서 이러한 모티프들이 어떤 조합으로 함께 전사 과정에 관여하는지 여부를 밝히는 작업은 중요한 일이다. 본 논문에서 진화 연산을 응용하여, 다양한 조건 하에 전사 과정에 중요하게 작용하는 모티프들의 조합을 알아보았고, 그 결과를 기본적인 k-Means 알고리즘 등과 비교하여 제안한 방법이 유전자들의 상관관계에 있어서 보다 우수한 결과를 보임을 알 수 있었다.
-
-
Concept Verification of Three-Layer DOI Detectors for Small Animal PET
Hong, Seong Jong,Kwon, Sun Il,Ito, Mikiko,Lee, Geon Song,Sim, Kwang-Souk,Park, Kwang Suk,Rhee, June Tak,Lee, Jae Sung IEEE 2008 IEEE transactions on nuclear science Vol.55 No.3
<P> Improved spatial resolution without sacrificing sensitivity is one of the most challenging developmental goals for small animal PET scanners. The 3-layer configuration that we propose here utilizes relative offsets of half a crystal pitch in x- and y-directions, and pulse shape discrimination to obtain depth of interaction (DOI). Three layers of crystals with a dimension 1.5<TEX>$\,\times\,$</TEX>1.5<TEX>$\,\times\,$</TEX>7.0mm <TEX>$^{3}$</TEX> were composed of a L <TEX>$_{0.2}$</TEX> GSO (Lu<TEX>$_{0.4}$</TEX> Gd<TEX>$_{1.6}$</TEX> SiO<TEX>$_{4}$</TEX>: Ce) crystal layer and a L<TEX>$_{0.9}$</TEX> GSO (Lu<TEX>$_{1.8}$</TEX> Gd <TEX>$_{0.2}$</TEX> SiO<TEX>$_{4}$</TEX> : Ce) crystal layer aligned with each other, and a L <TEX>$_{0.9}$</TEX> GSO crystal layer offset at half a crystal pitch in x- and y-directions. The L<TEX>$_{0.9}$</TEX> GSO crystal layer was attached to a Hamamatsu H9500 flat-panel PMT. The devised small animal PET scanner has a diameter of 84 mm with one detector ring, and can be upgraded to two detector rings. GEANT4 Monte-Carlo simulation was used to estimate sensitivities of <TEX>$\sim 12\hbox{\%}$</TEX> and <TEX>$\sim 20\hbox{\%}$</TEX>, respectively, at the center of one and two PMT ring system with an energy window of 350 <TEX>$\sim$</TEX> 750 keV. We present flood images with peak-to-valley ratios of about 5–6 obtained using <TEX>$^{22}$</TEX> Na and layer identification capability of <TEX>$\sim 99\hbox{\%}$</TEX> with pulse shape analysis, and verified the basic concepts of multi-layer small animal PET. </P>
-
Seong Jong Hong,Chan Mi Kim,Sung Mook Cho,Heon Woo,Guen Bae Ko,Sun Il Kwon,June Tak Rhee,In Chan Song,Jae Sung Lee IEEE 2011 IEEE transactions on nuclear science Vol.58 No.3
<P>Integrated PET/MRI units with simultaneous acquisition capability are set to play an important role in studies of human breast and prostate imaging and brain function. However, to take advantage of existing MRI units in hospitals and institutions, minimally modified combined PET MRI is highly desirable. In addition, the current MRI trend is to utilize powerful body coils to transmit radio-frequency (RF) waves and local RF coils to receive signals. The authors propose a silicon photomultiplier (SiPM) PET equipped with optical fiber bundles that transfer photons from scintillation crystal to SiPM. To investigate the feasibility of SiPM PET using optical fiber bundles, the authors studied the performances of SiPM/scintillator couplings using single optical fibers and a fiber bundle. GEANT4 Monte-Carlo simulation was used to study scintillation photon transfer from scintillation crystals to the SiPM. This simulation showed that light loss, due to the bending of an optical fiber, is not significant for a fiber with a diameter of 2.0 mm and a bending radius of greater than 25 mm. To validate the GEANT4 Monte-Carlo simulation, several simple detectors were assembled and tested. Simulation results agreed reasonably well with experimental results. Two Hamamatsu multi-pixel photon counters (MPPCs) were tested using double clad optical fibers of 1.5 mm and 2.0 mm diameter, and 25 mm and 50 mm bending radius, respectively. When two MPPCs were directly attached to 2.0 × 2.0 × 10.0 mm<SUP>3</SUP> LYSO crystals, a ~14% energy and a ~1.3 ns coincidence timing resolution were obtained at full width half maximum (FWHM). With one of the MPPCs attached to an optical fiber of 1.5 mm diameter, 50 mm bending radius, and length 300 mm, energy and coincidence timing resolutions were 27% and 2.2 ns, respectively. With an optical fiber bundle made of bare fibers with 1.5 mm diameter and length 100 mm, an ~ 26% energy resolution was obtained. Even though the Monte-Carlo simulation showed light loss was not significant for a single 90° turn of bending, the mechanical integrity of the optical fiber, especially the absence of cracks which can be caused by sharp bending, seemed to be a far more important constraint on sharp bending. These initial results are encouraging with respect to the use of combined SiPM PET using optical fibers.</P>
-
A Four-Layer DOI Detector With a Relative Offset for Use in an Animal PET System
Mikiko Ito,Jae Sung Lee,Sun Il Kwon,Geon Song Lee,Byungsik Hong,Kyong Sei Lee,Kwang-Souk Sim,Seok Jae Lee,June Tak Rhee,Seong Jong Hong IEEE 2010 IEEE transactions on nuclear science Vol.57 No.3
<P>For animal PET systems to achieve high sensitivity without adversely affecting spatial resolution, they must have the ability to measure depth-of-interaction (DOI). In this paper, we propose a novel four-layer PET system, and present the performances of modules built to verify the concept of the system. Each layer in the four-layer PET system has a relative offset of half a crystal pitch from other layers. Performances of the four-layer detector were estimated using a GATE Monte Carlo simulation code. The proposed system consists of six H9500 PMTs, each of which contains 3193 crystals. A sensitivity of 11.8% was obtained at the FOV center position of the proposed system. To verify the concept, we tested a PET module constructed using a H9500 flat panel PMT and LYSO crystals of cross-sectional area 1.5 × 1.5 mm<SUP>2</SUP>. The PET module was irradiated with a 1.8 MBq <SUP>22</SUP>Na radiation source from the front or side of the crystals to obtain flood images of each crystal. Collimation for side irradiation was achieved using a pair of lead blocks of dimension 50 × 100 × 200 mm<SUP>3</SUP>. All crystals in the four layers were clearly identified in flood images, thus verifying the DOI capability of the proposed four-layer PET system. We also investigated the optimal combination of crystal lengths in the four-layer PET system using the GATE Monte Carlo simulation code to generate events from simulated radiation sources, and using the ML-EM algorithm to reconstruct simulated radiation sources. The combination of short crystal lengths near radiation sources and long crystal lengths near the PMT provides better spatial resolution than combinations of same crystal lengths in the four-layer PET system.</P>
-
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
