• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.347-347
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• 2000

Nowadays, the Laser image is used to realize multi-media show for events, an advertising media and 3D simulation, realization of video image and so on. It is a hot issue to realize the laser image like computer graphic image. The image used in laser projector is vector graphic image that is described by linking point to point. A computer makes this continuous vector graphic images so that the image shows as an animation. A control signal converted by a computer makes the laser projector draw image. Two motors and universal joint are used to realize 2D laser image in this study. Developing a controller applied Look-ahead algorithm and software to interface with personal computer, This study is the chief aim of improving difference of moving velocity that is appeared from edge of vector graphic image and disparity of graphic density.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.14 no.2
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• pp.108-120
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• 1989

The paper describes a new algorithm for reducing the edge degradation of a vector quantization(VQ) in low rates. This algorithm exploits several codebooks, one of which is adaptively selected by standard deviation(SD) of the vector currently being coded. Also, SD search method for reducing the complexity of codebook search is proposed. As a result, a proposed VQ has good performance anout 30 dB PSNR in the 0.4-0.7 bpp range.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.4
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• pp.575-581
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• 2000

In this paper, a new active phase shifter is proposed using a vector sum method, and a unique digital phase control method of the circuit is suggested. The proposed scheme was designed and implemented using a Wilkinson power combiner/divider, a branch line 3 dB quadrature hybrid coupler and variable gain amplifiers (VGAs) using gate FETs(DGFETs). Furthermore, it was also shown that the proposed scheme is more efficient and works properly with the digital phase control method.

• Smart Structures and Systems
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• v.17 no.2
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• pp.347-361
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• 2016

A two-stage method for damage detection in truss systems is proposed. In the first stage, a modal residual vector based indicator (MRVBI) is introduced to locate the potentially damaged elements and reduce the damage variables of a truss structure. Then, in the second stage, a differential evolution (DE) based optimization method is implemented to find the actual site and extent of damage in the structure. In order to assess the efficiency of the proposed damage detection method, two numerical examples including a 2D-truss and 3D-truss are considered. Simulation results reveal the high performance of the method for accurately identifying the damage location and severity of trusses with considering the measurement noise.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.9
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• pp.927-938
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• 1992

In 1-D subband coding system, a quadrature mirror filter (QMF) pair can be used to split a signal into two subbands and to reconstruct the original signal. In this paper, a pair of 1-D reconstruction filter for the subband coding system is introduced and a coding technique with classified vector quantization, based on energy distributions, for 16 subband images is presented. As computer simulation results show that the method can give similar perceptual quality with bit rate reduced by $20{\sim}30%$ of that of ordinary vector quantization.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.372-376
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• 2001

Due to several advantages of Pulse Width Modulation(PWM) Converter, such as unity power factor operation, elimination of low-order harmonics and regeneration of motor braking energy to source, the application range of PWM Converter has been rapidly extended in industrial application. Nowadays, vector control algorithm and space vector PWM(SVPWM) method are applied to improve the performances of PWM Converter, but vector control algorithm and SVPWM require to use Microprocessor and other digital devices in hardware, causing costly and somewhat large dimension system. In every practical application of energy conversion equipments, the design and implementation should be carried out considering cost and performance. High performance and low cost is the best choice for energy conversion equipments. So, this paper presents the practical design method and implementation results of 3-phase PWM Converter with analog hysteresis current controller, and verifies the performances of unit power factor operation and energy regeneration operation via experimental results.

• Bulletin of the Korean Mathematical Society
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• v.56 no.5
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• pp.1219-1233
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• 2019

Let $E{\rightarrow}M$ be an arbitrary vector bundle of rank k over a Riemannian manifold M equipped with a fiber metric and a compatible connection $D^E$. R. Albuquerque constructed a general class of (two-weights) spherically symmetric metrics on E. In this paper, we give a characterization of locally symmetric spherically symmetric metrics on E in the case when $D^E$ is flat. We study also the Einstein property on E proving, among other results, that if $k{\geq}2$ and the base manifold is Einstein with positive constant scalar curvature, then there is a 1-parameter family of Einstein spherically symmetric metrics on E, which are not Ricci-flat.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.221-224
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• 2009

본 논문에서는 OpenVG Specification에서 제안한 파이프라인을 기능별, 혹은 연산별로 그룹화 하여 하드웨어 구현에 적합한 새로운 파이프라인을 제안하였다. 래스터라이저에서는 스캔라인 알고리즘과 엣지 플래그 알고리즘의 장점들을 포함하는 스캔라인 엣지 플래그 알고리즘을 구현하여 적용하였으며, Non-Zero 룰을 만족하기 위해 엣지의 방향에 따라 Winding 횟수를 기록하기 위한 추가 버퍼를 이용하였다. 또한, 래스터라이저는 안티 앨리어싱을 위해 슈퍼 샘플링 과정을 수행한다. 액티브 엣지 생성 시 클리핑을 동시에 수행하여 이후 과정에서의 불필요한 연산을 줄였고, 액티브 엣지들의 정렬을 수행하지 않는 방법을 사용하여 처리 속도를 향상 시켰다. 본 연구에서 설계된 OpenVG Rasterizer는 크로노스 그룹에서 제공하는 샘플 이미지들을 사용하여 검증하였다.

• Proceedings of the KIPE Conference
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• 2020.08a
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• pp.330-331
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• 2020

In this paper, we propose a new three-dimension space vector pulse width modulation for three-phase four-wire inverter under line-to-line fault. In order to this method, the processes of selecting of the output voltage vectors and synthesizing the reference voltage vector are discussed. In addition, we deal with the calculation of the duty cycles for each sector. The experiments are provided to validate the effectiveness of the proposed method.

• Proceedings of the Korean Magnestics Society Conference
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• 1996.10a
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• pp.116-117
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• 1996