• Journal of Advanced Marine Engineering and Technology
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• v.38 no.6
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• pp.666-673
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• 2014

Finite Element Method(FEM) is the essential tools for analyzing structural and vibration problem. But common commercial program is high-priced and the usage is not easy. Hereby the authors developed FEM program by using Matlab, whose usage is very simple and whose performance is very high. For the convenience of use and calculating efficiency Component Mode Synthesis Method is adopted, which divides a structure by some sub-structures for easy handling, analyzes them by parts and analyzes the structure with encompassing Degrees of Freedom(DOF). And encompassed DOF could be restored to full DOF. To confirm the accuracy the program was applied to a flat plate, and the results were compared to experiment, and good agreements were achieved. The developed program is going to be opened to public.

• The KIPS Transactions:PartB
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• v.10B no.6
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• pp.611-618
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• 2003

In this paper, we describe a fuzzy inference approach for detecting and classifying shot transitions in video sequences. Our approach basically extends FAM (Fuzzy Associative Memory) to detect and classify shot transitions, including cuts, fades and dissolves. We consider a set of feature values that characterize differences between two consecutive frames as input fuzzy sets, and the types of shot transitions as output fuzzy sets. The inference system proposed in this paper is mainly composed of a learning phase and an inferring phase. In the learning phase, the system initializes its basic structure by determining fuzzy membership functions and constructs fuzzy rules. In the inferring phase, the system conducts actual inference using the constructed fuzzy rules. In order to verify the performance of the proposed shot transition detection method experiments have been carried out with a video database that includes news, movies, advertisements, documentaries and music videos.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.10A
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• pp.1072-1077
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• 2007

In this paper, a power amplifier intermodulation distortion has been analyzed to improve linearity and the analysis results are used to minimize the distortion for linear power amplifier design. The proposed design technique is which the intermodulation distortions of the final amplifier are removed by driver intermodulation distortions. This proposed technique is based on AM to AM distortion analysis using power series, and AM to PM distortion analysis results using Bessel function. To verify this technique implement a cellular HPA(High Power Amplifier) 30W. From the results of the implementation and measurement for the linear power amplifier, the spurious characteristic is shown as 50 dBc at 1.98 MHz with 30 W with 20FA. These results show that distortion characteristics are improved as much as 10 dB in spurious characteristic compared with conventional design method.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.2
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• pp.352-359
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• 2008

This paper presents a controller implementation using model based controller design programs-System Identification Toolkit, Control Design Toolkit, Simulation module. This method is easier and simpler than conventional controller design method. To implement speed control system of DC motor, a CompactRIO, Real-Time(RT) cntroller provided by NI(National Instruments), is used as hardware equipment. Firstly transfer function of DC motor drive system, which was a control target plant, can be acquired through System Identification Toolkit by using test input signal applied to motor and output signal from motor. And designing of pole-zero compensator satisfying desired control response performance through Control Design Toolkit, designed speed control response can be tested through Simulation Module. Finally LabVIEW program is converted to real-time program and downloaded to CompactRIO real-time controller Through experimental results to real DC motor drive system, designed speed control response is compared to simulation results.

• Journal of KIISE:Computing Practices and Letters
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• v.5 no.4
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• pp.385-394
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• 1999

제품을 설계하는 디자이너나 엔지니어는 많은 시간과 노력을 들이지 않고서 그들이 설계한 3차원 제품 모델에 대한 사실적인 이미지를 원한다. 디자인 프로세스의 초기인 개념 설계에서부터 설계검증, 그리고 가공 과정에서 사실적인 이미지가 매우 유용하므로, 대부분의 주요 CAD 제작사는 그들의 CAD 소프트웨어에 고급 렌더링 기능을 추가하고 있다. 상용의 CAD/CAM 모델러에서는 NURB 곡면을 기초로 모델링을 수행하므로, NURB 곡면을 렌더링할 수 있는 패키지가 필요하다. VIF(Visual InterFace) 렌더링 라이브러리는 A-buffer 방식과 Ray tracing 방식의 두 가지 고급 렌더링 모드를 제공한다. 다각형은 물론 NURB 곡면을 입력으로 받아 사용자가 설정한 표면의 각종 계수, 원하는 view와 설정된 광원에 따라 이미지를 만들고 다양한 형태로 출력시킬 수 있는 다양한 기능을 제공한다. 본 논문에서는 VIF 렌더링 라이브러리에 대한 구조와 기능별로 분류된 함수에 대하여 설명하며, 실제로 CAD/CAM 시스템과 통합되어 구상설계에서부터 3차원 설계 모델링에 이르기까지의 제조공정에서 설계검증 툴로써 어떻게 활용되고 있는가에 대하여 기술한다.Abstract Engineers and industrial designers want to produce a realistic-looking images of a 3D model without spending a lot of time and money. Photo-realistic images are so useful from the conceptual design, through its verification, to the machining, that most major CAD venders offer built-in as well as add-on photo-realistic rendering capability to their core CAD software. Since 3D model is consists of a set of NURB surfaces in commercial CAD packages, we need a renderer which handles NURB surface as well as other primitives.A new rendering library called VIF (Visual InterFace) provides two photo-realistic rendering modes: A-buffer and Ray tracing. As an input data it takes NURB surfaces as well as polygonal data and produces images in accordance with the surface parameters, view and lights set by user and outputs image with different formats. This paper describes the overall architecture of VIF and its library functions classified by their functionalities, and discusses how VIF is used as a graphical verification tool in manufacturing processes from the conceptual design to 3D modeling.

• Journal of KIISE:Software and Applications
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• v.28 no.10
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• pp.699-705
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• 2001

As it became possible to generate 3D sound on a PC environment due to the advances in computing performance and digital signal processing technology, 3D sound technology gains its focus in the multimedia area Specifically a two-channel based 3D sound technology is being studied by many researchers because of its space efficiency and economical structure. While the positional sound effect is simple in its implementation, the moving sound effect has many problems to be resolved as there are only discrete measured point of HRTF database. In this paper, we propose the method of generating smooth moving sound in a two-channel based 3D sound technique with respect to generating smooth trajectory, and the interpolation method of discrete measured HRTF data. We perform the tests in the PC environment and prove the utility of the proposed method.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.11
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• pp.998-1007
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• 2015

The $H_{\infty}$ control theory using LMI method is applied to design an attitude controller of radial type satellite that has strongly coupled channels due to the large product of inertia. It is observed that the cross-over frequency of open-loop with $H_{\infty}$ controller is lower than that of open-loop without controller, which is not typical phenomenon in an optimal control design result: it is interpreted that due to a large product of inertia, there is certain limit in increasing agility of satellite by just tuning weighting function. ${\mu}$-analysis is performed to verify the stability and performance robustness with the assumption of +/-5% MOI variation. ${\mu}$-analysis result shows that the variation of principal MOI degrades the stability and performance robustness more than the variation of POI does.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.7B
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• pp.695-705
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• 2002

In this paper, we propose a simple open loop transmit diversity (TD) scheme for the wideband code division multiple access (W-CDMA) systems in Rician multipath fading channels such as rural area or satellite channels where line-of-sight (LOS) paths are in presence. The proposed scheme does not require any pre-processing of transmit data, resulting in simpler structure as compared to conventional closed loop transmit adaptive array (TxAA) and open loop space-time transmit diversity (STTD). We analytically derive the probability density function of signal-to-noise ratio at the Rake receiver output and the uncoded bit error rate performance of the proposed scheme. Extensive simulation is Performed to verify the analytical performance of the proposed scheme under typical Rician multipath fading channel environments. Moreover, comparative results with the conventional TxAA and STTD are also provided. Simulation results show that the proposed scheme shows slightly better performance than the conventional open loop STTD under the channels with very weak LOS components, however, it significantly outperforms the STTD under the channels with dominant LOS components, and achieves a close performance of ideal closed loop TxAA.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.3B
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• pp.462-473
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• 2010

The RFID system has the security problem of location tracking and user privacy. In order to solve this problem, the cryptographic access method using hash function is difficult to in real applications. Because there is a limit of computing and storage capacity of Tag, but the safety is proved. The lightweight authentication methods like HB and LMAP guarantee the high efficiency, but the safety is not enough to use. In this paper, we use the AES for RFID Authentication, and solve the problem of using fixed key with key change step by step. The symmetric keys of the tag and server are changed by the random number generated by tag, reader and server successively. This could prevent the key exposure. As a result, the output of the tag and reader always changes. These key changes could make it possible to prevent eavesdropping, replay attack, location tracking and spoofing.

• Journal of the Korean Institute of Intelligent Systems
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• v.15 no.3
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• pp.289-293
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• 2005

Pattern classification extracts various types of pattern information expressing objects in the real world and decides their class. The top priority of pattern classification technologies is to improve the performance of classification and, for this, many researches have tried various approaches for the last 40 years. Classification methods used in pattern classification include base classifier based on the probabilistic inference of patterns, decision tree, method based on distance function, neural network and clustering but they are not efficient in analyzing a large amount of multi-dimensional data. Thus, there are active researches on multiple classifier systems, which improve the performance of classification by combining problems using a number of mutually compensatory classifiers. The present study identifies problems in previous researches on multiple SVM classifiers, and proposes BORSE, a model that, based on 1:M policy in order to expand SVM to a multiple class classifier, regards each SVM output as a signal with non-linear pattern, trains the neural network for the pattern and combine the final results of classification performance.