• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(1)
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• pp.193-196
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• 2000

A new medium access control protocol is proposed to support stable wireless Internet services. Using the characteristics of the uplink Internet traffic and a Voice-Packet multi-session mode, the proposed protocol transmits the uplink Internet traffic via the voice traffic channel of silent duration in a multi-session mode. Out simulation results show that the proposed protocol guarantees stable wireless Internet services under heavy loads.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.105.2-105
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• 2002

$\textbullet$ Statically stable walk with COG(center of gravity) $\textbullet$ Dynamically stable walk with ZMP(zero moment point) $\textbullet$ Dynamically adaptational stable walk with FRI(foot ratation indicator) $\textbullet$ Simplified inverted pendulum model approach $\textbullet$ Analysis posture of biped's foot as passive joint $\textbullet$ Stability compensation method of FRI against falling down $\textbullet$ Simulation of ZMP and FRI to real biped robot IWR-III

• Nuclear Engineering and Technology
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• 제52권8호
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• pp.1826-1833
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• 2020

Administration of stable iodine has been considered a best measure to protect the thyroid from internal irradiation by radioiodine intake, and its efficacy on thyroid protection has been quantitatively evaluated in several simulation studies on the basis of simple iodine biokinetic models (i.e., three-compartment model). However, the new iodine biokinetic model adopted by the International Commission on Radiological Protection interprets and expresses the thyroid blocking phenomenon differently. Therefore, in this study, the new model was analyzed in terms of thyroid blocking and implemented to reassess the protective effects and to produce dosimetric data. The biokinetic model calculation was performed using computation modules developed by authors, and the results were compared with those of experimental data and prior simulation studies. The new model predicted protective effects that were generally consistent with those of experimental data, except for those in the range of stable iodine administration -72 h before radioiodine exposure. Additionally, the dosimetric data calculated in this study demonstrates a critical limitation of the three-compartment model in predicting bioassay functions, and indicated that dose assessment 1 d after exposure would result in a similar dose estimate irrespective of the administration time of stable iodine.

• Communications for Statistical Applications and Methods
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• 제8권1호
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• pp.257-269
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• 2001

The simulation is used to estimate an overflow probability in a stable parallel network with coupled inputs. Since the general simulation needs extremely many trials to obtain such a small probability, the fast simulation is proposed to reduce trials instead. By using the Cramer’s theorem, we first obtain an optimally changed measure under which the variance of the estimator is minimized. Then, we use it to derive an importance sampling estimator of the overflow probability which enables us to perform the fast simulation.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2006년도 추계 종합학술대회 논문집
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• pp.264-268
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• 2006

본 논문에서는 안정적 유체 애니메이션 기법을 이용한 불과 연기 애니메이션에 대해서 기술한다. 휴대전화의 연산 성능이 발전하면서 3D 콘텐츠와 고급 어플리케이션의 구현이 가능하게 되었다. 이러한 배경을 활용하여 지금까지 PC 기반에서 주로 개발되었던 유체 시뮬레이션을 모바일 장치에서 구현하였다. 안정적 유체 애니메이션 기법을 사용한 불 시뮬레이션은 실시간 렌더링을 목표로 하였으며 외부환경과 불 시뮬레이션 사이의 상호작용을 구현하였다. 그리고 모바일 3D 게임 콘텐츠에 불 애니메이션을 결합하여 게임의 객체 혹은 배경으로 사용 가능하도록 실용성을 더하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1115-1119
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• 2007

Five control methods (Speed Control, PID Gain Scheduling, Loop Time Control, Simple PID, Switching Control) have been applied to the control of an Inline Co-axial valve by the simulation of AMESim. The simulation results have shown that the speed control method is the most stable and the fastest way to reach to the set point in the simulation of the flow control. Moreover, It has been found that the five control methods have the almost same characteristics in the power consumption, the counter electromotive force, and the motor angular velocity. According to the analysis results, the fast and stable control characteristics of the speed control method is the most suitable for the flow control using a inline co-axial valve with a DC(BLCD) motor.

• 디지털콘텐츠학회 논문지
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• 제19권4호
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• pp.815-819
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• 2018

본 논문에서는 Foot Placement Estimator (FPE)를 사용하여 point foot을 갖는 이족 로봇의 3차원 시뮬레이션을 진행하고 이족로봇의 균형유지를 연구하였다. FPE 방법은 에너지 보존에 근거한 제어 방법으로서 보행 중인 로봇의 모든 에너지가 위치 에너지로 변환되는 지점에 로봇이 발을 디뎌 몸체가 넘어지지 않고 균형을 유지하며 이동하도록 하는 제어방법이다. 본 연구에서는 로봇이 이동하지는 않고 제자리에서 균형을 유지하며 서 있는 시뮬레이션을 진행하였다. 이를 위해 point foot을 갖는 6자유도 이족 로봇을 모델링하였으며 바닥과의 접촉 및 마찰 환경을 구현하였다. 로봇의 무게는 1kg이며 지면과 무게 중심점과의 거리는 1m로, 무게중심점은 로봇 몸체의 정 중앙에 위치하도록 설계하였다. 다음으로 로봇 몸체의 각속도와 직선속도 그리고 무게 중심점의 높이로 부터 FPE 지점을 계산하고 로봇이 해당 지점을 디뎌 균형을 유지하게 끔 하였다. 몸체의 초기 각도를 $5^{\circ}$, $-5^{\circ}$로 변화시키며 시뮬레이션 한 결과, 모든 초기 조건에서 로봇이 쓰러지지 않고 자세의 균형을 유지하며 서 있는 것을 확인할 수 있었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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• pp.119-121
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• 2007

PID control is windely used to control stable processes, however, its application to integrating processes is less common. In this paper, we proposed a simple PID controller tuning method for integrating processes with time delay to meet a sensitive function $M_s$. With the proposed PID tuning method, we can obtain stable integrating processes using PD controller in inner feedback loop and a loop transfer function with desired stable specification. This guarantees both robustness and performance. Simulation examples are given to show the good performance of the proposed tuning method to other methods.

• 전기학회논문지
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• 제56권11호
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• pp.2010-2016
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• 2007

PID control is windely used to control stable processes, However, its application to integrating processes is less common. In this paper, we proposed a stable PID controller tuning method for integrating processes with time delay using model reduction method. For proposed model reduction method, it disconnect an integrating factor from integrating processes and reduces separate process using reduction method. and it connect an integrating factor to reduced model. We can obtain stable integrating processes using P controller in inner feedback loop and PID tuning is then used to cancel the pole of the feedback loop. This guarantees both robustness and performance. Simulation examples are given to show the good performance of the proposed tuning method comparing with other methods.

• 한국수소및신에너지학회논문집
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• 제18권1호
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• pp.12-25
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• 2007

Numerical simulation of the natural gas steam reforming process for on-site hydrogen production in a $H_2$ fueling station was conducted on the basis of process material and heat balances. The effects of reforming parameters on the process efficiency of hydrogen production were investigated, and set-point values of each of the parameters to minimize the sizes of unit process equipments and to secure a stable operability of the reforming process were suggested. S/C ratio of the reforming reactants was found to be a crucial parameter in the reforming process mostly governing both the hydrogen production efficiency and the stable operability of the process. The operation of the process was regarded to be stable if the feed water(WR) as a reforming reactant could evaporate completely to dry steam through HRSG. The optimum S/C ratio was 3.0 where the process efficiency of hydrogen production was maximized and the stable operability of the process was secured. The optimum feed rates of natural gas(NGR) and WR as reforming reactants and natural gas(NGB) as a burner fuel were also determined for the hydrogen production rate of $27\;Nm^3/h$.