• Proceedings of the Optical Society of Korea Conference
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• 2001.02a
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• pp.216-217
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• 2001

광섬유와 평면 도파로를 결합한 도파로 구조에서 광 결합 현상은 다양한 응용 가능성 때문에 이론적으로 또는 실험적으로 많은 연구가 되어오고 있다. 광섬유는 단일모드를 이용하고 적당한 곡률이 주어진 블록에 고정한 후 연마하여 클래딩의 일부를 제거하고, 그 상부에 다중모드 평면 도파로(Multi-Mode Overlay Waveguide; MMOW)를 구성한다. 제작된 결합기 구조에서 평면 도파로는 광섬유의 감쇠장 결합(Evanescent field coupling)을 유도하게 되므로, 소자의 특성은 평면 도파로의 구조와 조건에 의해 결정된다. (중략)

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.3
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• pp.563-568
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• 2008

We present a method to implement an $M{\times}N$ switching system by use of an $M{\times}1$ multimode planar waveguide and N hologram filters. The $M{\times}1$ multimode planar waveguide provides the pass of optical signals and changes the output speckle patterns by applying an electrical signal. The complex speckle patterns generated from the multimode planar waveguide are recorded into the N hologram filters and used as the code for destination. The feasibility of our method is experimentally demonstrated.

• Journal for History of Mathematics
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• v.18 no.4
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• pp.125-134
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• 2005

In this paper we introduce the historical development of the theories for the planar domains. Also we deal with the representative domains of the planar domains and study the properties of the new representative domains.

• Proceedings of the KIPE Conference
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• 2019.07a
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• pp.378-379
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• 2019

본 논문은 LCL 필터를 사용하는 3상 계통연계 인버터의 그리드 전류 오차를 개선하고 고조파 왜곡 현상을 억제하기 위해 다중 공진제어 기법을 슬라이딩 평면에 적용한 슬라이딩 제어기(SMC)를 제시한다. 일반적으로 시스템 파라미터가 변경되거나 계통에 외란이 발생할 경우 슬라이딩 평면이 표류하는 현상이 나타나며 이러한 표류 현상은 시스템 정상상태 오차와 시스템에 고조파 왜곡 현상을 일으키고 계통연계 인버터의 전류 품질에 심각한 영향을 미치게 된다. 이러한 현상을 해결하기 위해 적분 함수가 추가된 SMC가 제안되었으나 해당 제어기는 효과적으로 정상상태 오차를 제거하는 반면 슬라이딩 평면의 표류현상을 충분히 줄여주지 못하는 한계를 가지고 있다. 이러한 정상상태 오차와 표류현상을 제거하기 위해 다중 공진제어 조건을 슬라이딩 평면 함수에 추가한 제어기를 제시한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.4
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• pp.388-393
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• 2019

As a fiiting method to data with outliers, RANSAC(RANdom SAmple Consensus) based algorithm is widely used in fitting of line, circle, ellipse, etc. CUDA is currently most widely used GPU with massive parallel processing capability. This paper proposes an efficient CUDA implementation of multiple planes fitting using RANSAC with 3d points data, of which one set of 3d points is used for one plane fitting. The performance of the proposed algorithm is demonstrated compared with CPU implementation using both artificially generated data and real 3d heights data of a PCB. The speed-up of the algorithm over CPU seems to be higher in data with lower inlier ratio, more planes to fit, and more points per plane fitting. This method can be easily applied to a wide variety of other fitting applications.

• Journal of the Korean Institute of Intelligent Systems
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• v.24 no.4
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• pp.385-391
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• 2014

This paper proposes fuzzy disturbance observer based multiple sliding surface control scheme for nonlinear systems with mismatched disturbance. In order to stabilize nonlinear systems with mismatched disturbance, a controller based on multiple sliding surface control scheme is designed. In addition, a fuzzy disturbance observer is used to estimate the disturbance. Using the fuzzy disturbance observer, "explosion of terms" problem and chattering problem were solved. The stability of the proposed control scheme is analyzed by Lyapunov stability theory. For the verification, we apply the proposed method to numerical examples and compare its result with that of the applied nonlinear disturbance observer based sliding mode control.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.6
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• pp.37-44
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• 1999

In this paper, we present a new sliding surface with a time-varying repeated root for fast and robust tracking of higher-order uncertain systems. The repeated root is moved to target one with stabilizing the closed-loop time-varying system in sliding mode. This initial root is obtained so that shifting distance of the surface may be minimized with respect to an initial error, and the intercept is produced so that the surface may pass the initial error. Under the allowable input, fast shifting of the surface and movement of the repeated root enable the error convergence rate to be increased. The proposed sliding mode control makes the error always remain on the surface from the beginning, and therefore, the system is more insensitive to parameter uncertainties and external disturbances. In simulation, the effectiveness of the proposed method is proved by comparison with the conventional one.

• Proceedings of the Korean Society of Computer Information Conference
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• 2021.07a
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• pp.601-604
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• 2021

본 논문에서는 모바일 디바이스의 카메라로부터 얻은 RGB이미지를 분석하여 장애물을 안정적으로 탐지할 수 있는 프레임워크를 제안한다. 본 논문에서는 장애물을 안정적으로 찾기 위해 RANSAC(Random Sample Consensus)기반의 다중 평면 방식을 이용한 위험감지 시스템을 제안한다. 우리의 접근 방식은 RGB영상으로부터 특징점(Feature point)을 추출하고, 특징점을 분석(Feature point analysis)하여 영상내의 평면을 감지한다. 복잡한 지형으로 인해 생성되는 다수의 평면을 RANSAC을 통해 단일 평면으로 정규화하고, 이로부터 특징점을 분류하기 위한 기준점을 계산한다. 모바일 디바이스의 위치와 회전 제약 없이 효과적으로 기준평면(Reference plane)을 탐색할 수 있고, 영상 내 특징점을 실시간으로 계산한다. 다양한 실험을 통해 기준평면과 장애물과의 거리를 파악하여 장애물을 효과적으로 분류하는 결과를 얻었다. 우리의 기법은 실세계에서의 위험요소를 감지하고 모바일 디바이스 사용자의 안전성 확보에 활용할 수 있을 거라 기대한다.

• Journal of IKEEE
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• v.21 no.4
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• pp.412-415
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• 2017

In this paper, we propose a multi license plate recognition system using high resolution $360^{\circ}$ omnidirectional IP camera. The proposed system consists of a planar division part of $360^{\circ}$ circular image and a multi license plate recognition part. The planar division part of the $360^{\circ}$ circular image are divided into a planar image with enhanced image quality through processes such as circular image acquisition, circular image segmentation, conversion to plane image, pixel correction using color interpolation, color correction and edge correction in a high resolution $360^{\circ}$ omnidirectional IP Camera. Multi license plate recognition part is through the multi-plate extraction candidate region, a multi-plate candidate area normalized and restore, multiple license plate number, character recognition using a neural network in the process of recognizing a multi-planar imaging plates. In order to evaluate the multi license plate recognition system using the proposed high resolution $360^{\circ}$ omnidirectional IP camera, we experimented with a specialist in the operation of intelligent parking control system, and 97.8% of high plate recognition rate was confirmed.

• Journal of the Korean Institute of Intelligent Systems
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• v.20 no.2
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• pp.279-284
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• 2010

The plane curve approach which was proposed by Boukharouba et. al. is a multi-threshold selection method through searching peak-valley based on histogram cumulative distribution function. However the method is required to select parameters to compose plane curve, and the shape of plane curve is affected according to parameters. Therefore detection of peak-valley is effected by parameters. In this paper, we propose an entropy maximizing-based method to select optimal plane curve parameters, and propose a multi-thresholding method based on the selected parameters. The effectiveness of the proposed method is demonstrated by multi-thresholding experiments on various images and comparison with other conventional thresholding methods based on histogram.