• Journal of Mechanical Science and Technology
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• 제15권9호
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• pp.1240-1247
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• 2001

A robust control design scheme using well-developed SISO techniques is proposed for maglev vehicles that are inherently unstable MIMO systems. The proposed separate control method has basically two control loops: a stabilizing loop by a pole-placement technique, and a performance loop using a novel optimal LQ loop-shaping technique. This paper shows that the coupling terms involved in maglev vehicles with multimagnets should not be neglected but compensated for their stability and performance robustness. The robustness properties of the proposed control system are then evaluated under variations of vehicle masses and air gaps through a computer simulation. This paper also describes the reason why the proposed control technique can be suggested as a tool using only SISO techniques in controlling unstable MIMO systems such as maglev vehicles.

• 한국전자거래학회지
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• 제15권1호
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• pp.1-16
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• 2010

Confidentiality is one of the most important requirements of information protection systems. The access control technique has been used to provide confidentiality, but it has fundamental problems in that it cannot prevent violations of confidentiality committed by authorized users. Information flow control is a technique introduced to resolve such problems, and many approaches based on programming languages have been proposed. However, it is not easy for a programmer to implement the technique at the source code level. Furthermore, the practicality of information flow control is difficult to demonstrate because it does not provide control over programs that have already been developed. This paper proposes a method that enables a practical information flow control through using a protected area, a separate part of computer system storage. Case studies are given to show its usefulness.

• 한국정보통신학회논문지
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• 제10권1호
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• pp.74-79
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• 2006

본 논문에서는 RMI와 JMF를 이용하여 분산 미디어 객체 실시간 스트리밍을 하기 위한 기법을 제시한다. 즉, 분산 객체의 복잡한 제어를 RMI를 사용하여 간소화 하고 멀티캐스트를 지원하지 않는 네트워크 환경에서 JMF를 사용하여 일대다 실시간 스트리밍을 하기 위한 기법을 다룬다. 자바 기반의 RMI와 JMF를 사용하여 전송과 제어를 분리 할 수 있으며 이를 응용하여 플랫폼에 독립적인 멀티미디어 서비스 애플리케이션의 개발에 사용 가능하다.

• Journal of Power Electronics
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• 제14권1호
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• pp.115-124
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• 2014

This paper presents the implementation of two-arm modulation (TAM) technique for the independent control of a two-induction motor drive fed by a five-leg inverter (FLI). A carrier-based space vector pulse width modulation technique for TAM is proposed to generate switching signals for FLI. Two independent three-phase space vector modulators are utilized to control two motors. The motor drive system applies two separate indirect field-oriented control methods. The stationary voltage outputs from the vector control are synthesized in the three-phase space vector modulator to generate switching signals for FLI. The performance of the independent control of the motors and the voltage utilization factor are likewise analyzed. Simulation and experimental results verify the effectiveness of the proposed method for the independent control of the two-motor drive system. The proposed technique is successfully validated by dSPACE DS1103 experimental work.

• 제어로봇시스템학회논문지
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• 제9권7호
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• pp.536-546
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• 2003

We propose an object extraction technique adequate for the radial shape's radar signal structure for the purpose of implementing ARPA(Automatic Radar Plotting Aid) installed in the vessel. The radar signal data are processed by interpolation and accumulation to acquire a qualified image. The objects of the radar image have characteristics of having different shape and size as it gets far from the center, and it is not adequate for clustering generally. Therefore, this study designs a new vigilance distance model of elliptical shape and adopts this model in the ART2 neural network. We prove that the proposed clustering method makes it possible to extract objects adaptively and to separate the connected objects effectively.

• Journal of Chest Surgery
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• 제25권10호
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• pp.1152-1156
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• 1992

A 64 year-old male patient with annulo-annulo-aortic ectasia[AAE] due to cystic medial necrosis was successfully treated with Cabrol operation with Cabrol trick. The technique consist of implantation of a composite valve graft within the aneurysmal sac with reattachment of the coronary ostia using a separate, small tube graft and creation of a communication between the closed perigraft space and right atrium for bleeding control. The patient had a postoperative gastrointestinal bleeding but successful recovery was achieved eventually.

• 전기학회논문지P
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• 제50권3호
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• pp.117-124
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• 2001

The aim of this paper is to develop a controller of multi-phase bipolar brushless DC (MPB BLDC) motors for an electric bicycle. A MPB BLDC motor has a Permanent magnet rotor in which the magnetic arrangement is radial to the shaft and integral to the rotor laminations. This technique concentrates flux, giving a higher flux density than a surface-mounted PM motor and increases reluctance torque. The stator of MPB BLBC motor has parallel winding, allowing multi-phase separate independent controllability. It gets much more high power than wye-connection at same low voltage. The conventional techniques of exited with modulation(EWM), bidirection control, and partial square wale control are Proposed with one H-bridge and two photo sensors per phase. The Proposed controller is satisfied for the limited speed control and designed for system stability Experimental results show the performance of the proposed controller of MPB BLDC motors for an electric bicycle.

• Journal of information and communication convergence engineering
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• 제15권3호
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• pp.193-198
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• 2017

In this study, we propose a three-dimensional (3D) visualization technique of occluded objects using integral imaging with a plenoptic camera. In previous studies, depth map estimation from elemental images was used to remove occlusion. However, the resolution of these depth maps is low. Thus, the occlusion removal accuracy is not efficient. Therefore, we use a plenoptic camera to obtain a high-resolution depth map. Hence, individual depth map for each elemental image can also be generated. Finally, we can regenerate a more accurate depth map for 3D objects with these separate depth maps, allowing us to remove the occlusion layers more efficiently. We perform optical experiments to prove our proposed technique. Moreover, we use MSE and PSNR as a performance metric to evaluate the quality of the reconstructed image. In conclusion, we enhance the visual quality of the reconstructed image after removing the occlusion layers using the plenoptic camera.

• 대한기계학회논문집
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• 제19권7호
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• pp.1780-1786
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• 1995

The main goal of the present study is to establish the techniques and methodolgies of turbine performance test through evaluating the objective turbine test piece, and checking the reliability of the self-developed test facility by performing a series of turbine tests under ambient temperature condition. A high speed coupling, a lubrication system and a test bed of the test facility were modified through a series of preliminary test in order to reduce the vibration and oil leakage. The flowrate control of the test facility and data acquisition were accomplished by using a software called "Labview" The measurement of shaft horse power and control of rotational speed according to the conditions of turbine rotation were performed by a separate system. The preliminary evaluation of the measured data suggests that the developed test facility and the test technique can be used reliably for the performance test of turbines with the minor improvement.provement.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1694-1700
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• 2004

In this paper, we propose the AWLS/MFT (Adaptive Weighed Least Squares/ Modulation Function Technique) devised by A. E. Pearson et al. for the transfer function estimation of a modal system and investigate the performance of several algorithms, the Gram matrix method, a Luenberger Observer (LO), Least Squares (LS), and Recursive Least Squares (RLS), for the estimation of initial conditions. With the benefit of the Modulation Function Technique (MFT), we can separate the estimation problem into two phases: the transfer function parameters are estimated in the first phase, and the initial conditions are estimated in the second phase. The LO method produces excellent IC estimates in the noise free case, but the other three methods show better performance in the noisy case. Finally, we compared our result with the Prony based method. In the noisy case, the AWLS and one of the three methods - Gram matrix, LS, and RLS- show better performance in the output Signal to Error Ratio (SER) aspect than the Prony based method under the same simulation conditions.