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Kwangdon Kim,Hakjae Lee,Jinwook Jang,Yonghyun Chung,Donghoon Lee,Chanwoo Park,Jinhun Joung,Yongkwon Kim,Kisung Lee 대한전자공학회 2017 IEIE Transactions on Smart Processing & Computing Vol.6 No.1
Radioactive materials are used in medicine, non-destructive testing, and nuclear plants. Source localization is especially important during nuclear decommissioning and decontamination because the actual location of the radioactive source within nuclear waste is often unknown. The coded-aperture imaging technique started with space exploration and moved into X-ray and gamma ray imaging, which have imaging process characteristics similar to each other. In this study, we simulated 21x21 and 37x37 coded aperture collimators based on a modified uniformly redundant array (MURA) pattern to make a gamma imaging system that can localize a gamma-ray source. We designed a 21x21 coded aperture collimator that matches our gamma imaging detector and did feasibility experiments with the coded aperture imaging system. We evaluated the performance of each collimator, from 2 mm to 10 mm thicknesses (at 2 mm intervals) using root mean square error (RMSE) and sensitivity in a simulation. . In experimental results, the full width half maximum (FWHM) of the point source was 5.09° at the center and 4.82° at the location of the source was 9°. We will continue to improve the decoding algorithm and optimize the collimator for high-energy gamma rays emitted from a nuclear power plant.
양전자 방출 단층 영상장치의 시스템 구조 및 촬영대상에 특화된 반복적 사이노그램 공백 보간 방법
김광돈(Kwangdon Kim),이기성(Kisung Lee),이학재(Hakjae Lee),정용현(Yonghyun Chung),주성관(Sungkwan Joo) 대한전자공학회 2016 대한전자공학회 학술대회 Vol.2016 No.6
Various geometries have been used to develop the positron emission tomography (PET) scanner in order to improve PET image resolution, and to detect events with higher sensitivity. However, the blind zones or inter-detector gaps for each detector block result in various artifacts and image distortions in reconstruction images. To compensate for this distortion, the literature offers several gap-filling methods, such as linear interpolation methods and iterative gap-filling methods. Uygar Tuna et al. proposed a novel gap-filling algorithm that shows superior gap-filling results, which can be attributed to the PET scanner geometry. However, the algorithm is not dedicated to imaging objects, and should be manually optimized for these objects. We aim to develop a gap-filling algorithm, in particular the filter mask design method of the algorithm, which optimizes the filter to the imaging object by an adaptive and iterative process, rather than by manual means. We generated the data set with two analytic phantom studies, Shepp-Logan and Jaszczak. The proposed algorithm shows results that compare to those of the manually optimized discrete-cosine transform 2 (DCT2) algorithm without perfect or full information of the imaging object, and improve the image quality of the reconstructed image.
Reconstruction of In-beam PET for Carbon therapy with prior-knowledge of carbon beam-track
Kim, Kwangdon,Bae, Seungbin,Lee, Kisung,Chung, Yonghyun,An, Sujung,Joung, Jinhun The Institute of Electronics and Information Engin 2015 IEIE Transactions on Smart Processing & Computing Vol.4 No.6
There are two main artifacts in reconstructed images from in-beam positron emission tomography (PET). Unlike generic PET, in-beam PET uses the annihilation photons that occur during heavy ion therapy. Therefore, the geometry of in-beam PET is not a full ring, but a partial ring that has one or two openings around the rings in order for the hadrons to arrive at the tumor without prevention of detector blocks. This causes truncation in the projection data due to an absence of detector modules in the openings. The other is a ring artifact caused by the gaps between detector modules also found in generic PET. To sum up, in-beam PET has two kinds of gap: openings for hadrons, and gaps between the modules. We acquired three types of simulation results from a PET system: full-ring, C-ring and dual head. In this study, we aim to compensate for the artifacts that come from the two types of gap. In the case of truncation, we propose a method that uses prior knowledge of the location where annihilations occur, and we applied the discrete-cosine transform (DCT) gap-filling method proposed by Tuna et al. for inter-detector gap.
Kim, Kwangdon,Lee, Kisung,Lee, Hakjae,Joo, Sungkwan,Kang, Jungwon Springer-Verlag 2018 Japanese journal of radiology Vol.36 No.1
<P>The proposed algorithm works well for various types of scanning object and shows results that compare to those of the manually optimized DCT2 algorithm without perfect or full information of the imaging object.</P>
Hardware Sizing Method for Information System in Korea
Jonghei Ra,Haeyong Jung,Kwangdon Choi 보안공학연구지원센터 2006 International Journal of Multimedia and Ubiquitous Vol.1 No.4
Accurate system sizing are essential for higher efficiency of investment. Accurate system sizing benefits are generally viewed in terms of the avoidance of excess equipment and lost opportunity costs by not being able to support business needs. We are proposed calculating method for hardware components that is CPU, memory and system, data disk according to the application system types
나종회(Jonghei Ra),최광돈(Kwangdon Choi) 한국IT서비스학회 2009 한국IT서비스학회지 Vol.8 No.3
Hardware sizing is determinated by an increasing rate of operated business and characteristic of adapted technology which are imported systems. Because it is very difficult for intuitive decision of hardware sizing's appropriateness. But in sprite of difficulty, for maximizing the utilization of information resource and the effect of information investment in public sector are need to correctness hardware sizing. In this paper, we proposed hardware sizing method for OLTP server that is make up it's faults of proper proposal method. Our study certainly will act as a catalyst for higher investment-efficiency of future information systems in public sector.
Development of Compact, Cost-effective, FPGA-Based Data Acquisition System for the iPET System
Min, Eungi,Kim, Kwangdon,Lee, Hakjae,Kim, Hyun-Il,Chung, Yong Hyun,Kim, Yongkwon,Joung, Jinhun,Kim, Kyeong Min,Joo, Sung-Kwan,Lee, Kisung Springer-Verlag 2017 Journal of medical and biological engineering Vol.37 No.6
<P>Positron emission tomography (PET) is a nuclear medicine imaging technology used to analyze physiological processes. An in-beam PET is used to verify the delivered dose during ion-beam therapy. Our group investigates the prototype C-shaped PET system, which is called the iPET system. In this study, we develop an expendability-enhanced field-programmable gate array (FPGA)-based data acquisition system for the iPET. We organize this data acquisition (DAQ) system using only one DAQ board, to ensure a compact and cost-effective DAQ system. We design the FPGA using modular functions, which include synchronization, deserialization, pulse height analysis, and data packaging functions. As a result, energy spectra and well-separated 9 x 9 flood images of the entire detector module are achieved. We obtain reconstructed PET images of point source (4 mm diameter), three cylindrical phantoms (3 cm diameter), and four sphere phantoms (3.0, 2.2, 1.3 and 1.0 cm diameter). We achieve approximately 300 kcps of maximum single count rate. The obtained results prove the compactness and cost-effectiveness of the proposed DAQ system.</P>
정보시스템 용량산정방식에 관한 탐색적 연구 : 공공부문 H/W 규모산정을 중심으로
나종회(Jonghei Ra),최광돈(Kwangdon Choi) 한국IT서비스학회 2004 한국IT서비스학회지 Vol.3 No.2
Interest about Information infrastructure construction is enlarged socially according to arrival of information age, and various information systems are constructed for efficient business processing, customer service in public sector. According to subjective method for performance improvement for information system of public sector and engine that propel information system construction because it is no definite hardware sizing guidelines for information system caterer is calculating resource volume of information system. It is situation that problem of excess of scale or reduce sizing is happening and is causing various kind of problems that is waste of information budget and service decline thereby. In this research we proposed hardware sizing framework for information system that is applied to public sector.
나종회(Jonghei Ra),최광돈(Kwangdon Choi),정해용(Haeyong Jung) 한국IT서비스학회 2006 한국IT서비스학회지 Vol.5 No.1
According to the policy for "e-Korea construction" of Korean government, Investment of information system during the past decade are dramatically increasing. More than a half of this investment is cost of hardware infrastructure. So, accurate hardware sizing are essential for higher efficiency of investment. Accurate hardware sizing benefits are generally viewed in terms of the avoidance of excess equipment and lost opportunity costs by not being able to support business needs. Unfortunately, however, little research effort to make the hardware sizing methodology are doing. We propose a sizing method for information system in public sector. This method is determinate empirical study that are gathering and analyzing cases, making method and reviewing expert. Finally we are proposed calculating method for hardware components that is CPU, memory, internal and external disk according to the application system type which is OLTP, Web, WAS. Our study certainly will act as a catalyst for higher investment-efficiency of the future information programs in public sector.