• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권6호
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• pp.2649-2669
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• 2020

In this paper, we analyze the secrecy performance of single-input multiple-output (SIMO) relay systems over κ-μ shadowed fading channels. Based on considering relay model employing decode-and-forward (DF) protocol, two security evaluation metrics, namely, secure outage probability (SOP) and probability of strictly positive secrecy capacity (SPSC) are studied, for which closed-form analytical expressions are derived. In addition, Monte Carlo results prove the validity of the theoretical derivation. The simulation results confirm that the factors that enhance the security include large ratio of (μ_D, μ_E), (m_D, m_E), (L_D, L_E) and small ratio of (k_D, k_E) under the high signal-to-noise ratio regime.

• Interaction and multiscale mechanics
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• 제3권3호
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• pp.257-266
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• 2010

A novel resonance based proximity DC current sensor is proposed. The sensor consists of a piezo sensed and actuated cantilever beam with a permanent magnet mounted at its free end. When the sensor is placed in proximity to a wire carrying DC current, resonant frequency of the beam changes with change in current. This change in resonant frequency is used to determine the current through the wire. The structure is simulated in micro and meso scale using COMSOL Multi physics software and the sensor is found to be linear with good sensitivity.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1995년도 Proceedings of the Korea Automation Control Conference, 10th (KACC); Seoul, Korea; 23-25 Oct. 1995
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• pp.428-431
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• 1995

In this paper we propose an on-line tuning method by using genetic algorithm for robust minimax I-PD controller based on new criterion. The new criterion is the Integral of Squared Error (ISE) with a penalty of the derivative of manipulated variable. The work focuses on robust tuning of I-PD controller's parameters in the presence of plant parameter uncertainty. The result of several simulation studies are provided to illustrate the performance of this robust tunig method.

• 대한전자공학회논문지
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• 제27권3호
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• pp.79-85
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• 1990

$\Gamma$계곡의 nonparabolicity를 고려하여 $Al_{0.48}\In_{0.52}As/Ga_{0.47}In_{0.53}As$ 변조 도핑 구조에서의 hot-electron 전송을 Monte Carlo 방법으로 연구하였다. 계산결과로부터 nonparabolicity는 2차원 전자의 속도를 크게 감소시킴을 알 수 있었다.

• Nuclear Engineering and Technology
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• 제48권3호
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• pp.795-798
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• 2016

Transmission X-ray tubes based on carbon nanotube have attracted significant attention recently. In most of these tubes, tungsten is used as the target material. In this article, the well-known simulator Geant4 was used to obtain some of the tungsten target parameters. The optimal thickness for maximum production of usable X-rays when the target is exposed to electron beams of different energies was obtained. The linear variation of optimal thickness of the target for different electron energies was also obtained. The data obtained in this study can be used to design X-ray tubes. A beryllium window was considered for the X-ray tube. The X-ray energy spectra at the moment of production and after passing through the target and window for different electron energies in the 30-110 keV range were also obtained. The results obtained show that with a specific thickness, the target material itself can act as filter, which enables generation of X-rays with a limited energy.

• Journal of the Optical Society of Korea
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• 제14권4호
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• pp.383-387
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• 2010

The stereoscopic three-dimensional (3D) display provides a 3D image by inducing binocular disparity for the observers who wear special glasses. With the rapid progress in flat panel display technologies, the stereoscopic 3D display is becoming a new benefit-model of the current display industry, and several kinds of commercial stereoscopic 3D products have been released and are attracting people. Nowadays, the motion picture quality of the 3D image becomes as important as resolution or luminance since most of the commercial 3D products are 3D televisions or 3D monitors which are required to display a clear motion 3D image. In this paper, an analysis and simulation of the motion picture quality of stereoscopic 3D image is proposed, and a comparison of the motion picture performance among the current stereoscopic 3D technologies is also provided.

• 대한방사선기술학회지:방사선기술과학
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• 제25권1호
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• pp.83-88
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• 2002

This work was peformed as a basic research in the application of Monte Carlo methods for planning treatments by electron beams. Depth doses, beam profiles and isodose curves in water phantoms were calculated for monoenergetic electron beams with 6, 9, and 12 MeV. The calculated depth doses and beam profiles are almost consistent with their known values. If allowances are made for distributions in electron beam energies, we are confident that the agreement between our calculations and measured values will significantly improve. In conclusion, our work shows that similar Monte Carlo calculations could be applied for geometries In human body in planning electron beam treatments.

• Journal of international Conference on Electrical Machines and Systems
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• 제3권3호
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• pp.289-297
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• 2014

This paper proposed a novel high performance sensorless control scheme for IPMSM based on an extended nonlinear state observer. The gain-matrix of the observer has been derived by using state linearization method. Steady state errors in estimated rotor position and speed due to parameter inaccuracy have been analyzed, and an equivalent flux error is defined to represent the overall effect of parameter errors contributing to the wrong convergence of the estimated rotor speed as well as rotor position. Then, an online compensation strategy was proposed to limit the estimation errors in rotor position and speed. The effectiveness of the extended nonlinear state observer is validated through simulation and experimental test.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.177-179
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• 2008

This paper, we proposed the theoretical model which includes series resistance $R_s$ and shunt resistance $R_{sh}$ of single-crystalline PV module and used numerical method based on physics. Series resistance $R_s$ was derived from approach for p-n junction diode instead of established form obtained from the simulator with irradiance changes. Electrical output characteristics for PV modules to count the effect of $R_s$ were then studied. Finally simulation results were compared to experimental data leading to good agreement.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 1995년도 창립기념학술대회
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• pp.38-43
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• 1995

Effect of visualization as a tool for the education of fluid dynamics is mainly discussed. Visualized images are much more understandable compared to the explanation using equations and texts. Several examples are presented to clarify this statement. Then, the software system for teaching fluid dynamics using the results by the numerical simulation is discussed. Two important issues on what is needed in the system are given. First, such systems should be capable of animating images. Second, such systems should be interactively used by students. Changing parameters, coefficients, equations, etc. themselves and watching the difference are important for them to understand the nature of physics underlying the equations. The teaching system with visualization is no doubt a good tool for introducing fluid dynamics.