• 대한수학회지
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• 제33권2호
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• pp.333-346
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• 1996

Let $A(\zeta, \partial)$ be a second order uniformly elliptic operator $$ A(\zeta, \partial )u = -\sum_{j, k = 1}^{n} \frac{\partial\zeta_i}{\partial}(a_{jk}(\zeta)\frac{\partial\zeta_k}{\partial u}) + \sum_{j = 1}^{n}b_j(\zeta)\frac{\partial\zeta_j}{\partial u} + c(\zeta)u $$ with real, smooth coefficients $a_{j, k}, b_j$, c defined on $\zeta \in \Omega, \Omega$ a bounded domain in $R^n$ with a sufficiently smooth boundary $\Gamma$.

• 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.376-379
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• 1995

To force an aircraft to track the specified path, the generation of the smooth desired trajectory is essential. In this paper, the cubic spline function is used to generate the trajectory which passes through the specified intercept points. The simulation results show that the desired trajectory generated by the spline interpolation is very smooth and the aircraft tracks it with small position errors.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2000년도 가을 학술발표논문집 Vol.27 No.2 (3)
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• pp.322-324
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• 2000

인터넷을 통한 실시간 멀티미디어 전송에 있어서 인터넷이 "Best effort" 서비스이기 때문에 지연과 지연변이 그리고 패킷 손실 등이 발생하게 되어 서비스의 질에 큰 영향을 미치게 된다. 더욱이 멀티미디어 데이터는 시간에 민감하다는 속성 때문에 네트워크상의 지연이나 지연 변이는 클라이언트 측의 재생지연과 버퍼의 Underflow, 미디어간 동기의 어긋남을 발생시킬 수 있다. 본 논문에서는 이를 해결하기 위해서 네트워크나 서버 측에서의 접근이 아닌 클라이언트의 측면에서 접근하였다. 기존 adaptive한 기법[2][3]을 도입, 개선하므로써 클라이언트가 네트워크의 상태에 적응하여 지연과 지연변이의 영향을 최소화시키도록 클라이언트의 버퍼관리와 playback control을 설계하였다.ol을 설계하였다.

• 디지털산업정보학회논문지
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• 제18권4호
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• pp.23-30
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• 2022

Recently, traffic congestion and environmental pollution have occurred due to population concentration and vehicle increase in large cities. Various studies are being conducted to solve these problems. Most of the traffic congestion in cities is caused by traffic signals at intersections. This paper proposes a dynamic traffic light control (DTLC) scheme to support safe vehicle operation and smooth traffic flow using real-time traffic information based on VANET. DTLC receives instantaneous speed and directional information of each vehicle through road side units (RSUs) to obtain the density and average speed of vehicles for each direction. RSUs deliver this information to traffic light controllers (TLCs), which utilize it to dynamically control traffic lights at intersections. To demonstrate the validity of DTLC, simulations were performed on average driving speed and average waiting time using the ns-2 simulator. Simulation results show that DTLC can provide smooth traffic flow by increasing average driving speed at dense intersections and reducing average waiting time.

• 대한의생명과학회지
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• 제11권1호
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• pp.23-29
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• 2005

Molecular imaging with targeted contrast agents enables tissues to be distinguished by detecting specific cell-surface receptors. In the present study, a ligand-targeted acoustic nanoparticle system is used to identify angioplasty-induced expression of tissue factor by smooth muscle cell within carotid arteries. Pig carotid arteries were overstretched with balloon catheters, treated with tissue factor-targeted or a control nanoparticle system, and imaged with intravascular ultrasound before and after treatment. Tissue factor-targeted emulsion bound and increased the echogenicity and gray-scale levels of overstretched smooth muscle cell within the tunica media, versus no change in contralateral control arteries. Expression of stretch-induced tissue factor in carotid artery media was confirmed by immunohistochemistry. The potential for abnormal thrombogenicity of balloon-injured arteries, as reflected by smooth muscle expression of tissue factor, was imaged using a novel, targeted, nanoparticulate ultrasonic contrast agent.

• Journal of Power Electronics
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• 제17권3호
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• pp.733-743
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• 2017

This paper develops a coordinated control strategy of the doubly fed induction generator (DFIG) system based on repetitive control (RC) under generalized harmonic grid voltage conditions. The proposed RC strategy in the rotor side converter (RSC) is capable of ensuring smooth DFIG electromagnetic torque that will enable the possible safe functioning of the mechanical components, such as gear box and bearing. Moreover, the proposed RC strategy in the grid side converter (GSC) aims to achieve sinusoidal overall currents of the DFIG system injected into the network to guarantee satisfactory power quality. The dc-link voltage fluctuation under the proposed control target is theoretically analyzed. Influence of limited converter capacity on the controllable area has also been studied. A laboratory test platform has been constructed, and the experimental results validate the availability of the proposed RC strategy for the DFIG system under generalized harmonic grid voltage conditions.

• 한국동물위생학회지
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• 제31권4호
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• pp.449-456
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• 2008

The differentiation of mouse embryonic stem(ES) cell into smooth muscle cells(SMC) may play a major role in cardiovascular development and under pathophysiological conditions. Therefore, in the present study, we have examined the differentiation of ES cells and its related gene expression. SMC differentiation was indicated by cellular morphology and time-dependent induction of dibutyryl adenosine 3,5-cyclic monophosphate(DBcAMP)and retinoic acid(RA) on smooth muscle ${\alpha}$-actin($SM{\alpha}A$), smooth muscle myosin heavy chain(SMMHC) gene expression. The control was undifferentiated ES cells(protein expressions represent 50-60kDaOct-4). The results of this study show that morphology of embryoid body and confirmation of $SM{\alpha}A$ expression by immunocytochemistry. Moreover, SMMHC and desmin expression was significantly increased by time dependent manner(5, 7, 15 days), in contrast to $SM{\alpha}A$ expression was slightly decreased on 15days. In conclusion, DBcAMP and RA stimulate mouse ES cells differentiation into SMC and enhanced $SM{\alpha}A$, SMMHC and desmin expression.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1418-1423
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• 2003

In this paper, a nonlinear controller based on sliding mode control is applied to a two -wheeled Welding Mobile Robot (WMR) to track a smooth-curved welding path at a constant velocity of the welding point. T he mobile robot is considered in terms of dynamics model in Cartesian coordinates and its parameters are exactly known . To obtain the controller, the tracking errors are defined, and the two sliding surfaces are chosen to guarantee that the errors converge to zero asymptotically. Two cases are to be considered: fixed torch and controllable torch. In addition, a simple way of measuring the errors is introduced using two potentiometers. The simulation results are included to illustrate the performance of the control law.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.99-102
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• 2006

This paper proposes a DITC(Direct Instantaneous Torque Control of SRM (Switched Reluctance Motor) using a novel 4-level converter for smooth torque control and high efficiency. DITC of SRM is very useful for smooth torque control, but the driving efficiency is low due to advanced current that does not produce torque. For the high efficiency control of SRM, fast excitation and demagnetization of phase current are required. A novel 4-level converter and a new control scheme are present to improve the driving efficiency. The proposed DITC of SRM using 4-level converter is verified by computer simulation.

• Journal of Power Electronics
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• 제9권3호
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• pp.491-498
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• 2009

The hydraulic-oil pump is widely used for building machinery, brake systems of vehicles and automatic control systems due to its high dynamic force and smooth linear force control performance. This paper presents a novel direct instantaneous pressure control of the hydraulic pump system with SRM drive. The proposed hydraulic pump system embeds the pressure controller and direct instantaneous torque controller. Due to the proportional relationship between pump pressure and torque, pressure can be controlled by the motor torque directly. The proposed direct torque controller can reduce inherent torque ripple of SRM, and develop a smooth torque, which can increase the stability of the hydraulic pump. The proposed hydraulic pump system has also fast step response and load response. The proposed hydraulic pump system is verified by computer simulation and experimental results.