• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.3
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• pp.217-225
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• 2003

In this paper, in order to investigate the near field distribution characteristic of the Loop Antenna we simulated and measured the near field of a Loop Antenna using optical electric-field sensor in a large Chamber(8.5 m x 7 m x 7 m). The simulation methods were used MoM for frequency domain and FDTD for time domain. From the analysis results, it can be seen that the simulation and measurement results are very aggregated, and the optical electric-field sensor is a certificate of validity. In frequency domain, in case of the optical sensor with vertical polarization is located above the near vertical line of the Loop Antenna the signal strength level is more 15 ㏈ than with horizontal polarization. But in case of the optical sensor located above horizontal line of the Loop Antenna, signal strength level is not different. And, in the time domain, although input signal is positive, in the case of the optical sensor with vertical polarization is located above horizontal line of the Loop Antenna, it can be seen that the received pulse shape is negative.

• Journal of the Korean Society of Radiology
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• v.13 no.5
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• pp.773-778
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• 2019

Images using X-rays are essential to diagnosis, but noise is inevitable in the image. To compensate for this, a total variation (TV) algorithm was presented to reduce the patient's exposure dose while increasing the quality of the images. The purpose of this study is to verify the effect on the image quality in radiographic imaging according to the thickness of the additional filtration plate through simulation, and to evaluate the usefulness of the TV algorithm. By using the Geant4 Application for Tomographic Emissions (GATE) simulation image, the actual size, shape and material of the Polymethylmethacrylate (PMMA) phantom were identical, the contrast to noise ratio (CNR) and coefficient of variation (COV) were compared. The results showed that the CNR value was the highest and the COV the lowest when applying the TV algorithm. In addition, we can acquire superior CNR and COV results with 0 mm Al in all algorithm cases.

• Proceedings of the KIPE Conference
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• 2012.11a
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• pp.209-210
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• 2012

본 연구에서는 종전의 X자형 임피던스 망을 갖는 Z-소스 인버터(X-ZSI)에 비해 부스트 성능을 향상시킨 변압기를 이용한 ZSI(X-STZSI)의 임피던스 망을 설계하였다. 사용된 변압기는 이상적인 변압기에 자화 인덕턴스를 고려한 모델을 이용하였다. 따라서 임피던스 망을 구성하는 변압기의 자화 인덕턴스와 커패시터 용량을 산정하는 방법을 함께 설명하고 PSIM 시뮬레이션을 통해 검증하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.11a
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• pp.529-530
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• 2009

웹 브라우저 환경에서 통신 및 화면 갱신 기능을 제공하기 위해서 최근까지 ActiveX를 제공하였다. 하지만 ActiveX 배포에 따른 보안 문제 또는 Spyware 등으로 인한 개인 정보 노출 가능성을 배제할 수 없게 되었다. 따라서 본 논문에서 제안하는 웹 브라우저 환경에서의 통신 모듈 및 화면 갱신 기법을 통해서 ActiveX의 단점을 보완하려 한다. 또한, 여러 분야에서 적용 가능하지만 NMS 원격 감시 모니터링의 시뮬레이션을 통해서 적용 가능성을 검증하였다.

• Proceedings of the KAIS Fall Conference
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• 2009.05a
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• pp.855-858
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• 2009

우리나라 농어촌 지역은 경제 발전과 함께 식생활의 개선 및 주택 개량, 수세식 화장실 보급 확대등으로 생활 오수 발생량이 크게 늘고 있는 실정이다. 이에 1994년부터 정부는 하수도법에 의한 수질개선 대책 사업등으로 마을 하수도 사업이 진행되어 왔으나, 현재 몇몇 농어촌 지역의 마을하수도 시설의 노후화 및 처리용량 부적합 등으로 현재 질소, 인의 처리효율이 방류수 수질기준에 적합하지 못하여 주변 수역의 수질개선을 위한 고도처리개선이 필요한 실정이다. 따라서, 본 연구는 소규모 마을하수도처리시설에 적용하고자 하는 고도처리개선공정을 GPS-X(General Purpose Simulator) 시뮬레이션으로 계획수질을 추정하여 대상시설에 적합한 고도처리개선공정을 설계하였다. 측정결과, 각 반응조별 시뮬레이션에서 혐기조, 무산소조, SBR1, SBR2 모두 일정한 처리형태를 보였으며, 시뮬레이션을 통한 유출수 예측결과, SS의 경우 97.3%, BOD 97.5%, TCOD 87.3%, TP 81.1%, TN 74.5%의 제거효율을 보여, 안정적인 고도처리효과를 나타내는 것으로 판단된다.

• Journal of the Korea Society for Simulation
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• v.22 no.3
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• pp.81-87
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• 2013

This paper is about study how to decrese surge pressure that is occurred in excavator driving motor. We used computer simulation program SimulationX. It is also about the way finding design problem and approaching a solution through interpreting shape design sensitivity analysis. Programmes are below. First of all, finding shape fault by analyzing dynamic behavior of valves installed in hydraulic driving motor which is designed now. And drawing variable which is considered sensitive to improve dynamic efficiency among a lot of shape variables. Then, targeting that variable and examining dynamic efficiency stabilization tendency with controlling it. Finally, suggesting the most effective tuning method through variable combination as there are a lot of sensitive variables.

• Journal of the Korean Society of Radiology
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• v.12 no.7
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• pp.929-934
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• 2018

Studies for counting and detecting X-rays for the improvement of image quality and material analysis are active. In this work, the detector for X-ray photon counting was designed using Multi-pixel photon counter (MPPC) array and the detector characteristics were evaluated through simulation. Geant4 Application for Tomographic Emission (GATE) was used to obtain the position where the X-ray and the scintillation interacted, and this position was used as the light generation position of DETECT2000. 0.5 mm and 1 mm thick Gadolinium Aluminium Gallium Garnet (GAGG) scintillators were used and the light generated through a $4{\times}4$ array of MPPCs was acquired. The spatial resolution of the designed detector was evaluated by reconstructed image using the light signal acquired for each channel. We obtained images of more than 2 lp/mm in both 0.5 mm and 1 mm thick GAGG scintillation. When this detector is used in a X-ray system, a low-cost system capable of photon counting can be made.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.11
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• pp.1112-1120
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• 2008

The real-time distributed simulation at the present age concentrates on the construction of a system development environment in order to accomplish a synthetic battlefield environment connected with Live-Virtual-Constructive simulation and to realize the Simulation Based Acquisition which supports the life cycle of weapon system. Accordingly this paper describes the development environment of the UML modeling and simulation which integrates the system analysis and design methods performed during the conceptual design phase of the reconnaissance UAV system development. An integrated framework linked with the UML simulation and X-plane visualization is suggested to efficiently perform the system analysis and design, and finally the implementation contents, the analysis of experiment results and concluding remarks are described.

• Journal of Korea Game Society
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• v.9 no.5
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• pp.43-52
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• 2009

This paper analyzes the four game physics engines in terms of real time techniques. Real time physics is the technology that simplifies the physics-based simulation to apply for the real time applications such as game. Our study includes two commercial physics engines, Havok's Physics SDK and NVIDIA's PhysX SDK, and two open source projects, Open Dynamics Engine and Bullet physics engine. As a result, most of them covers rigid body dynamics and some include either deformable body simulation or fluids simulation, or both. For real time simulation, they adopt the simplified numerical methods, the effective in collision detection/response, and also use the parallel processing hardwares, i.e., multi core CPU, Physics processing unit(PPU), or graphics processing unit(GPU).

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.2
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• pp.425-432
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• 2019

Molecular dynamics simulations were carried out to analyze the impact on turbine rotational power based on nozzle shapes. y varying two parameters, turbine rotational velocity w and initial velocities ($V_x,V_y$) for generating molecules, turbine rotation velocities of molecules in turbine entrance arc region and turbine exit arc region were calculated. Average momentums were calculated over two regions, respectively and the differences (AMD) were compared and analyzed. The optimal range of w values to enhance AMD was investigated over 4 different nozzle shapes used, and an excellent nozzle shape to achieve more turbine rotational power was drawn.