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- 저자 : Song Hankyeol (검색결과 5 건)
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Timing pickoff method for improvement of timing resolution in AGPET
Song Hankyeol,Park Chanwoo,Baek Min Kyu,Lee Seongyeon,Kim Kyu Bom,Chung Yong Hyun 한국물리학회 2023 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.82 No.2
Small-animal positron emission tomography (PET) systems are widely used for pathological and pharmacological studies. For good image quality, the timing resolution should be kept as low as possible, so we proposed a pulse reconstruction method based on curve ftting using a bi-exponential model for digital timing pickof. To evaluate the proposed method, fve diferent digital timing algorithms, leading edge discrimination (LED), digital constant fraction discrimination (DCFD), maximum rising interpolation (MRI), initial rising interpolation (IRI), and pulse reconstruction (PR) were established and compared. A single gamma pulse obtained from the silicon photomultiplier (SiPM) was simulated and the timing resolution was calculated according to the algorithms. Additionally, these methods were applied to the real PET dataset obtained from the AGPET detector and the timing resolution was derived. The simulation results proved that the PR method showed constant timing resolution independent from pulse rise time and sampling rate. In the experimental results, the PR method showed the best timing resolution of 0.9 ns to compare other digital methods. The results demonstrated that the proposed PR method can improve the performance of the small-animal PET with a relatively slow ADC.
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Performance evaluation of an adjustable gantry PET (AGPET) for small animal PET imaging
Song, Hankyeol,Kang, In Soo,Kim, Kyu Bom,Park, Chanwoo,Baek, Min Kyu,Lee, Seongyeon,Chung, Yong Hyun Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.8
A rectangular-shaped PET system with an adjustable gantry (AGPET) has been developed for imaging small animals. The AGPET system employs a new depth of interaction (DOI) method using a depth dependent reflector patterns and a new digital time pickoff method based on the pulse reconstruction method. To evaluate the performance of the AGPET, timing resolution, intrinsic spatial resolution and point source images were acquired. The timing resolution and intrinsic spatial resolution were measured using two detector modules and Na-22 gamma source. The PET images were acquired in two field of view (FOV) sizes, 30 mm and 90 mm, to demonstrate the characteristic of the AGPET. As a result of in the experiment results, the timing resolution was 0.9 ns using the pulse reconstruction method based on the bi-exponential model. The intrinsic spatial resolution was an average of 1.7 mm and the spatial resolution of PET images after DOI correction was 2.08 mm and 2.25 mm at the centers of 30 mm and 90 mm FOV, respectively. The results show that the proposed AGPET system provided higher sensitivity and resolution for small animal imaging.
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문한결(Hankyeol Moon),김성민(Song Min Kim) 한국통신학회 2022 한국통신학회 학술대회논문집 Vol.2022 No.2
본 논문은 정확한 물체의 위치 추정을 위한 밀리미터파 FMCW 레이더 시스템을 구성하고 분석한다. 다양한 위치의 레이더에서 정보를 수집하여 공간적 다양성을 확보함으로써 거리 분해능을 향상시키며, 거리에 따라 성능이 악화되는 방위각 정보를 사용하지 않고 정확한 물체의 위치를 추정하는 것을 목표로 한다. 우리는 밀리미터파 레이더 삼각측량을 이용한 거리 분해능 향상을 달성하였으며, 이를 상용 레이더로 검증하였다. 우리의 방식을 사용하였을 때, 단일 레이더를 사용할 때 보다 약 30%의 성능이 향상하였음 확인하였다.
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RNX-71 추진제 기반 1.5KM 급 저고도 발사체(HELL-2) 설계 및 개발
이겸(Gyeom Lee),김영섭(Yeongseop Kim),오세진(Sejin Oh),조한결(Hankyeol Cho),유숙진(Sukjin Yu),송지민(Jimin Song) 한국추진공학회 2020 한국추진공학회 학술대회논문집 Vol.2020 No.11
지난 2020년 3월 발사되어 약 350m를 비행한 저고도 실증 발사체(HELL-1)의 비행 데이터를 바탕으로 하여 성능이 개량된 실증 발사체 2호기(HELL-2)를 개발하였다. 개량 발사체는 전번보다 향상된 1.5km 고도의 비행 성능을 가지며, 더 넓은 환경 범위에서의 전자장비와 동체 특성을 검증할 수 있도록 설계되었다. 에폭시 기반의 추진제인 RNX-71V 추진제를 기반으로 모터에 대한 내탄도 해석 및 지상 연소 테스트를 수행하였다. 더불어 동체의 공력설계, 외탄도 설계를 통합적으로 진행하였으며 비행궤적을 예측하였다. 이를 기반으로 본 사운딩 로켓은 2020년 9월 초 발사될 계획을 가지고 있다. Based on flight data of HELL-1 rocket which were launched in March 2020 and flew about 350 meters, our team is developing a performance-enhanced demonstration sounding rocket (HELL-2). Improved rocket is designed to fly about 1.5 km of altitude, so that electronic equipment and aerodynamic characteristics can be tested in a wider range of environments. Internal ballistics analysis and static combustion tests for the rocket motor were carried out. In addition, the flight trajectory was predicted based on aerodynamic analysis and exterior ballistics. It will be launched in early September 2020.
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Dong-Hoon Lee,Chanwoo Park,Cheol-Ha Baek,Chaeyeong Lee,Seung-Jae Lee,Hankyeol Song,Yong Hyun Chung Professional Technical Group on Nuclear Science 2017 IEEE transactions on nuclear science Vol.64 No.10
<P>Gamma-ray computed tomography (CT) has widely been used to inspect cracks, obstructions, and fluid flow in pipes. Previous studies have shown that the inspection accuracy is limited when materials in the pipe have a similar density. To overcome this drawback, we investigated a method to discriminate small density differences using a dual-energy gamma-ray CT. In this paper, the performance of a gamma-ray CT system was simulated using Geant4 Application for Tomographic Emission with three types of sources (Am-241, Co-57, and Cs-137). A polyvinyl chloride (PVC) pipe containing oil and sludge was modeled as a phantom. Sparsely acquired data were reconstructed using filtered back-projection and iterative total variation (TV) denoising algorithms. Each material discrimination procedure was performed with a postreconstruction technique. Our results clearly showed that the gamma-ray CT imaging with Am-241 and Co-57 sources and the TV denoising reconstruction algorithm can be used to inspect the internal structures based on discriminated images. The calculated areas of discriminated oil and sludge were within an error margin of 2% (oil: 78.4% and sludge: 21.6%) compared with the simulated phantom (oil: 80% and sludge: 20%). For both gamma sources, the calculated contrast-to-noise ratio (CNR) values with the TV denoising algorithm were the highest values for all structures (Am-241/Co-57: 18.03/28.95 for oil versus sludge, 41.67/31.53 for oil versus PVC pipe, and 23.64/31.53 for sludge versus PVC pipe). The feasibility of our approach and results indicates it usefulness for industrial fields that require structural inspections.</P>
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