• The KIPS Transactions:PartB
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• v.15B no.5
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• pp.407-412
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• 2008

Color segmentation is one of the most challenging problems in image processing especially in case of handling the images with cluttered background. Great amount of color segmentation methods have been developed and applied to real problems. In this paper, we suggest a new methodology. Our approach is focused on background extraction, as a complimentary operation to standard foreground object segmentation, using self-organizing feature selective property of unsupervised self-learning paradigm based on the competitive algorithm. The results of our studies show that background segmentation can be achievable in efficient manner.

• Journal of the Korean School Mathematics Society
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• v.12 no.4
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• pp.493-508
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• 2009

This study investigates aspects of the zone of proximal development (ZPD), the distance between the actual development and the potential development. Out of 18 university students taking a geometry course, two students with the same actual developmental level in the van Hiele model in the pre-test and post-test were interviewed for measuring their potential developmental level. Based on the communicational approach to cognition, the characteristics of the two interviewees' discourse on 3D reflective symmetry were identified. There were considerable differences between the two interviewees in terms of their potential developmental level. Methodological implications for how to investigate students' ZPD in mathematics education research were addressed.

• 한국정보교육학회:학술대회논문집
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• 2007.01a
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• pp.173-180
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• 2007

최근 모바일 기기의 활성화에 따라 M-learning (Mobile learning)이 활성화되고 있다. M-learning을 기반으로 한 코스웨어나 모듈 설계 시 학습자의 적극적 참여와 의미 있는 상호작용의 기회 제공과 실제적 환경에서의 교육활동을 지원하는 것에 초점을 맞추어야 한다. 근접발달영역이론 (Zone of Proximal Development : ZPD)이란 독자적으로 문제를 해결함으로써 결정되는 실제적 발달수준과 성인의 안내나 보다 능력 있는 또래들과 협동하여 문제를 해결함으로써 결정되는 잠재적 발달수준간의 거리이다. 한편, 스캐폴딩은 학습자의 근접발달영역을 변화시키며, 학습자가 스스로 학습할 수 있도록 도와주는 구체적인 방식이라 할 수 있다. 또한 스캐폴딩 (Scaffolding)은 학습자가 구조를 조직하고 새로운 지식을 구성하도록 교수자 또는 촉진자가 도와주면서 교수자와 학습자간에 상호작용하는 과정이다. 본 연구에서는 근접발달영역이론을 이용하여 모바일로 교사가 학습자에게 스캐폴딩을 제공하는 수업모형을 제안한다. 본 모형의 특징은 다음과 같다. 첫째, 문제해결을 위한 스캐폴딩만이 아니라 문제 해결 후 격려 스캐폴딩을 제공하여 학습력 강화가 이뤄지도록 하였다. 둘째, 교사와 학습자 사이에 다양한 스캐폴딩을 제공하여 상호작용을 강화하였다. 셋째, 자신에게 맞는 개별학습, 반복 학습이 가능하고 자기 주도적 학습이 강화되도록 하였다.

• The Transactions of the Korean Institute of Power Electronics
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• v.8 no.6
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• pp.496-503
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• 2003

SFC system has come to be used as drive large synchronous machine in many industry applications. Many papers have been presented on the control algorithm of SFC system, not the acceleration and start-up but the rated speed operation with line connection and the braking operation with regeneration which is used in the industry. This paper presents the whole section control algorithm for a large synchronous machine using SFC system. The results of experiment show that the proposed algorithm is proper and effective.

• Journal of the Korean Institute of Intelligent Systems
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• v.19 no.5
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• pp.615-621
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• 2009

TFT-LCD image consists of ununiform background, random noises and target defect signal components. Defects in TFT-LCD have some intensity variations compared to background region. It is sometimes difficult for human inspectors to figure out. In this paper, we propose multi-level threshold scheme for detection of the real defect using probability density function with Parzen Window. The experimental results show that the proposed algorithms produce promising results and can be applied to automated inspection systems for finding defects in the TFT-LCD image.

• Journal of the Korean Society of Propulsion Engineers
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• v.14 no.3
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• pp.39-51
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• 2010

Theoritical principles about the real gas equation of state are investigated and comparisons for the thermophysical properties of oxygen, hydrogen, and methane as the propellants of liquid rocket engine are carried out for the various conditions of pressure and temperature including supercritical conditions. The properties obtained using the real gas equation of state(Soave modification of Redlich-Kwong, Peng-Robinson equation of state, and extended corresponding states principle) have been compared with the results of applying the ideal gas equation of state. Differences of thermophysical properties among the models specifically at the liquid phase regime and their error ranges are addressed.

• Proceedings of the IEEK Conference
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• 2001.09a
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• pp.981-984
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• 2001

본 논문은 이동물체 영역을 신뢰성 있게 분리하는데 기초가 되는 seed를 정확하게 선정하고, 선정된 seed를 중심으로 영역을 확장함으로써 이동물체 영역을 분리하기 위한 방법을 제안한다. 고정된 카메라로부터 입력되는 연속된 영상열로부터 초기의 이동물체가 존재하지 않는 영상을 참고영상으로 하여 입력영상과의 차영상을 구하고 차영상의 히스토그램에서 배경잡음 모델링을 통해 배경잡음을 제거한다. 그리고 배경잡음이 제거된 차영상에서 Local Maxima 들을 이용해 후보 seed를 선정한 후, 이드의 특징값들을 분석하여 이동물체의 seed와 배경의 seed 를 결정하고 이 두 개의 seed를 기반으로 watershed 알고리즘을 적용하여 영역을 확장함으로써 이동물체 영역을 추출한다. 제안된 방법을 실제 상황에서 얻은 다양한 영상열에 적용한 결과, 기존의 영역분리 알고리즘보다 주위 잡음의 영향을 적게 받으며 효과적으로 이동물체를 분리할 수 있음을 확인할 수 있었다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.05a
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• pp.242-246
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• 2000

본 논문은 얼굴을 이용한 인증 단계의 전처리 단계로 복잡한 배경에서 효율적인 얼굴 추출 방법을 제안한다. 먼저 색상정보를 이용하여 얼굴로 추정되는 1차 영역을 찾고 2차로 색상정보와 자기정보를 이용하여 에지 정보를 추출하여 추정된 영역을 분리한다. 3차로 각 분리된 후보 영역에 얼굴 파라미터를 이용하여 후보영역을 합치면서 얼굴 영역을 추출한다. 온라인 인증을 위한 얼굴 영역 추출이기 때문에 인증 받고자 하는 사람의 얼굴은 전체 영역에서 가운데로 치우칠 것이라는 예상과 인증을 하기 위해서는 일정 크기를 가져야 한다는 가정 하에서 얼굴을 추출하였다. 실제 실험을 통하여 본 논문에서 제안하는 방법으로 실험한 결과 유용성을 확인 할 수 있었다.

• Journal of Korea Multimedia Society
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• v.15 no.4
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• pp.439-448
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• 2012

TFT-LCD panel images have non-uniform brightness, noise signal and defect signal. It is hard to divide defect signal because of non-uniform brightness and noise signal, so various divide methods have being developed. In this paper, we suggest method to divide defective regions on TFT-LCD panel image by estimating a menas of two different size of windows, which is suggested by Eikvil et al., and using difference of them. But in this method, the size of detectable defects is restricted by the size of window, hence it has inefficient problem that the size of window have to increase to divide a large defect region. To solve this problem we suggest an algorithm which can divide various size of defects, by using Multi-scale and restrict a detectable size of defects in each scale. To prove an efficiency of suggested algorithm, we show that resulting images of real TFT-LCD panel images and an artificial image with various defects.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.3C
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• pp.158-166
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• 2005

Even though post-processing methods based on projections onto convex sets (POCS) have shown good performance for blocking artifact reduction, it is infeasible to implement POCS for real-time practical applications. This paper proposes DCT domain post-processing method based on POCS. The proposed method shows very similar performance compared to the conventional POCS method, while it reduces tremendously the computational complexity. DCT domain POCS performs the lowpass filtering in the DCT domain, and it removes the inverse DCT and forward DCT modules. Through the investigation of lowpass filtering in the iterative POCS method, we define kth order lowpass filtering which is equivalent to the lowpass filtering in the kth iteration, and the corresponding kth order DCT domain POCS. Simulation results show that the kth order DCT domain POCS without iteration gives very similar performance compared to the conventional POCS with k iterations, while it requires much less computations. Hence the proposed DCT domain POCS method can be used efficiently in the practical post-processing applications with real-time constraints.