• Journal of the Korean Society of Radiology
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• v.1 no.3
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• pp.11-16
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• 2007

In this study, the potential of a newly developed simulation toolkit, GATE for the simulation of electronic portal imaging devices (EPID) in radiation therapy was evaluated by characterizing the performance of the metal plate/phosphor screen detector for EPID. We compared the performances of the GATE simulator against MCNP4B code and experimental data obtained with the EPID system in order to validate its use for radiation therapy.

• The Korean Journal of Health Service Management
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• v.13 no.3
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• pp.137-147
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• 2019

Objectives: This study aimed to identify the relationship between thoughts and psychological anxiety about nuclear power among Busan residents. Methods: Convenience sampling was used for this cross-sectional survey conducted from February 13 to 14, 2016. A total of 520 residents participated in the study and completed a self-administered questionnaire. Results: We found a significant association between negative thoughts and psychological anxiety about nuclear power. People older than 60 years (odds ratio (OR) 2.53, 95% confidence interval (CI) 1.41-4.54), who feared the possibility of radiation accidents (OR 1.75, 95% CI 1.17-2.62), considered nuclear power plants unsafe (OR 1.94, 95% CI 1.10-3.40), and believed the Gori nuclear power plant in Busan must be shut down (OR 1.84, 95% CI 1.22-2.79), had the highest anxiety about radiation exposure. Conclusions: The authors suggest the need for the formulation of a policy to provide people with precise information on nuclear power to increase their understanding and help eliminate unfounded negative thoughts. Furthermore, policy decisions about nuclear power must be based on social consensus.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.879-882
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• 1998

현재 보안 시스템으로 가장 많이 쓰이고 있는 것 중에 하나가 여러 지역의 카메라로부터 영상 신호를 받아서 하나의 모니터에 여러 영상을 분할 해서 보여주는 시스템이다. 이 시스템의 기능 중에서 가장 중요한 것은 각 지역의 영상을 실시간으로 처리해줄 수 있어야 하는데, 이를 위해서는 영상 데이터를 놓치지 않고 모두 메모리에 저장할 수 있어야 한다. 본 논문에서는 4개의 영상을 하나의 화면으로 4분할 하여 출력하기 위한 시스템을 FPGA를 사용하여 구현했다. 일반적으로 화면 분할하는 시스템은 흑백의 영상만을 출력하는데, 컬러 영상 신호인 RGB 5:6:5모드의 데이터를 사용하여 컬러 영상을 그대로 화면 분할하여 출력하는 시스템을 구성했다. 또한, 화면을 나누기 위한 PIP(Picture In Picture) 등의 전용칩은 분할 화면의 수가 늘어날수록 그 시스템의 크기가 커지므로 순수하게 FPGA를 이용하여 로직을 설계해서 직접 필드 메모리 (FIFO)를 콘트롤 하도록 설계했다. 동기화 되어 있지 않은 메모리에 저장한 각 영상 데이터를 하나의 영상화면에 동기화시키기 위한 방법으로 일정한 타이밍마다 각 영상 데이터를 선택하는 선택 알고리즘(Choice Algorithm)을 제시하여 적용하였다. 선택 알고리즘에 따라서 동기화 되어 있지 않은 메모리에 저장한 각 영상 데이터를 하나의 영상화면에 동기화 시키기위한 방법을 로직으로 구현하여 적용한 시스템을 만들어서 직접 실험 및 테스트를 실행하였다. 로직을 구현하기 위해 사용한 FPGA(Xilinx 5200 Series)는 XC5210-5이고, 비디오 데이터를 저장하기 위한 필드 메모리(FIFO)는 μPD42280-30를 사용하였는데, 좀더 여유 있는 데이터 저장을 통해 선명한 화질을 얻기 위해서는 FPGA와 메모리를 더 빠른 타입으로 사용하는 것이 바람직하다. 내용 전개를 살펴보면 제 1절에서 본 시스템의 필요성 및 개발 동기, 개발 배경등에 대해서 간단히 설명하고 제 2절에서는 전체 시스템의 구조에 대해서 설명하고 제 3절에서는 본 시스템의 구조 중에서 가장 중요한 메모리 컨트롤에 대해서 간단히 설명하고, 제 4절에서는 시스템을 구현시켜 실험 및 결과에 대해서 분석한다. 마직막으로 결론 및 향후 계획에 대해서 기술한다.

• Journal of the Korean Society of Radiology
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• v.12 no.3
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• pp.289-295
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• 2018

Most diagnostic devices in the medical field use X-ray sources, which emit energy spectra. In radiological diagnosis, the quantitative and qualitative analyses of X-rays are essential for maintaining the image quality and minimizing the radiation dose to patients. This work aims to obtain the X-ray energy spectra used in diagnostic imaging by Monte Carlo simulation. Various X-ray spectra are simulated using a Monte Carlo simulation tool. These spectra are then compared to the reference data obtained with a tungsten anode spectral model using the interpolating polynomial (TASMIP) code. The X-ray tube voltages used are 50, 60, 80, 100, and 110 kV, respectively. CdTe and a-Se detector are used as the detectors for obtaining the X-ray spectra. Simulation results demonstrate that the various X-ray spectra are well matched with the reference data. Based on the simulation results, an appropriate X-ray spectrum, in accordance with the tube voltage, can be selected when generating an image for diagnostic imaging. The dose to be delivered to the patient can be predicted prior to examination in the diagnostic field.

• The Journal of the Korea Contents Association
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• v.14 no.2
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• pp.475-481
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• 2014

The aim of this work was to develop the gamma camera system for small animal gamma imaging and environmental radiation monitoring imaging using a parallel hole collimator and pinhole collimator. The small gamma camera system consists of a CsI(Tl) scintillation crystal with 6 mm in thickness and $50{\times}50mm$ in area coupled with a Hamamatsu H8500C PSPMT, are resistive charge divider, pre-amplifiers, charge amplifiers, nuclear instrument modules (NIMs), an analog to digital converter and a computer for control and display. We have developed a radiation monitoring system composed of a combined pinhole gamma camera and a charge-coupled devices (CCD) camera. The results demonstrated that the parallel hole collimator and pinhole collimator gamma camera designed in this study could be utilized to perform small animal imaging and environmental radiation monitoring system. Consequently in this paper, we proved that our gamma detector system is reliable for a gamma camera which can be used as small animal imaging and environmental radiation monitoring system.

• The Journal of the Korea Contents Association
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• v.15 no.4
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• pp.350-356
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• 2015

The aim of this study is to perform simulations to design the detector module with crystal array by Monte Carlo simulation. For this purpose, a small animal PET scanner, employing module with 1~8 crystal array discrimination scheme, was designed. The proposed scanner has an inner diameter of 100 mm with detector modules in crystal array. Each module is composed of a 5.0 mm LSO crystal with a $2.0{\times}2.0mm^2$ sensitive area with a pitch 2.1 mm and 10.0 mm thickness. The LSO crystals are attached to the SiPM which has a dimension of $2.0{\times}2.0mm^2$. The detector module with crystal array of the designed PET detector was simulated using the Monte Carlo code GATE(Geant4 Application for Tomographic Emission). The detector is enough compensation for the loss of data in sinogram due to gaps between modules. The results showed that the high sensitivity and effectively reduced the problem about the missing data were greatly improved by using the detector module with 1 crystal array.

• Journal of the Korean Society of Radiology
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• v.11 no.7
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• pp.655-661
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• 2017

Sparse view CT has been widely used to reduce radiation dose to patient in radiation therapy. In this work, we performed sinogram restoration from sparse sampling data by using inpainting method for simulation and experiment. Sinogram restoration was performed in accordance with sampling angle and restoration method, and their results were validated with root mean square error (RMSE) and image profiles. Simulation and experiment are designed to fan beam scan for various projection angles. Sparse data in sinogram were restored by using linear interpolation and inpainting method. Then, the restored sinogram was reconstructed with filtered backprojection (FBP) algorithm. The results showed that RMSE and image profiles were depended on the projection angles and restoration method. Based on the simulation and experiment, we found that inpainting method could be improved for sinogram restoration in comparison to linear interpolation method for estimating RMSE and image profiles.

• Journal of radiological science and technology
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• v.40 no.1
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• pp.71-78
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• 2017

Scattered radiation is inherent phenomenon of x-ray, which occurs to the subject (or patient). Therefore it cannot be avoidable but also interacts as serious noise factor because the only meaningful information on x-ray radiography is primary x-ray photons. The purpose of this study was to quantify scattered radiation for various shooting parameters and to verify the effect of anti-scatter grid. We employed beam stopper method to characterize scatter to primary ratio. To evaluate effect on the projection images calculated contrast to noise ratio of given shooting parameters. From the experiments, we identified the scattered radiation increases in thicker patient and smaller air gap. Moreover, scattered radiation degraded contrast to noise ratio of the projection images. We find out that the anti-scatter grid rejected scattered radiation effectively, however there were not fewer than 100% of scatter to primary ratio in some shooting parameters. The results demonstrate that the scattered radiation was serious problem of medical x-ray system, we confirmed that the scattered radiation was not considerable factor of dig ital radiog raphy.

• Proceedings of the Korean Society of Computer Information Conference
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• 2014.07a
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• pp.311-314
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• 2014

본 논문은 Unity3D와 게임서버엔진인 ProudNet을 이용해 네트워크 게임을 개발한 방법을 설명하였다. ProudNet 서버를 Unity3D 클라이언트와 연결하여 네트워크 기능을 구현할 때 ProudNet의 어떤 기능을 쓰며 또 서버가 보낸 메시지를 클라이언트가 어떠한 방식을 이용하여 메시지를 처리하게 구현하였는지를 설명하였다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2014.07a
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• pp.495-498
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• 2014

본 논문에서는 2014년도 청강문화산업대학교 게임 전공의 졸업 작품 프로젝트 중 "Majesty on Sword:위대함이 깃든 검"이라는 액션 게임 개발을 정리한 것이다. 이 게임은 기본 게임이 가지고 있는 단점인 수많은 적들을 한꺼번에 사냥하는 과장된 액션의 지루하고 단순한 패턴에서 벗어나 스킬 시스템의 구현과 캐릭터의 사실적인 액션을 강조하여 기존 액션게임과 어떤 차별점을 두고 개발하였는지 기술한 논문이다.