• Journal of Advanced Navigation Technology
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• v.15 no.5
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• pp.696-704
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• 2011

In this paper, we propose a mobile robot navigation algorithm using data fusion of a monocular camera and ultrasonic sensors. Threshold values for binary image processing are generated by a fuzzy inference method using image data and data of ultrasonic sensors. Threshold value variations improve obstacle detection for mobile robot to move to the goal under poor illumination environments. Obstacles detected by data fusion of camera and ultrasonic sensors are expressed on the grid map and avoided using the circular planning algorithm. The performance of the proposed method is evaluated by experiments on the Pioneer 2-DX mobile robot in the indoor room with poor lights and a narrow corridor.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.5
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• pp.2291-2297
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• 2012

X-ray fluorescence sprectrum signal include the continuum. XRF analysis the components of material by the amplitude of peaks. XRF remove the noise and background. To remove the noise, we apply the smoothing filter. And background removal methods applied such as SNIP, Morphology, Threshold methods. In this paper, we applied Threshold using DWT. Interval threshold method divide the some blocks in particular levels. We propose the method that is divided the particular level.

• Proceedings of the Korean Society of Computer Information Conference
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• 2023.07a
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• pp.283-285
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• 2023

이상 탐지는 데이터에서 일반적인 범주에서 크게 벗어나는 인스턴스 또는 패턴을 식별하는 중요한 작업이다. 본 연구에서는 시계열 데이터의 특징 추출을 위한 비지도 학습 기반 방법과 정규화 흐름의 결합을 통한 이상 탐지 프레임워크를 제안한다. 특징 추출기는 1차원 합성곱 신경망 기반의 오토인코더로 구성되며, 정상적인 시퀀스로만 구성된 훈련 데이터를 압축하고 복원하는 과정을 통해 최적화된다. 추출된 시계열 데이터의 특징 맵은 가능도를 최대화하도록 훈련된 정규화 흐름의 입력으로 사용된다. 이와 같은 방식으로 훈련된 이상 탐지 시스템은 테스트 샘플에 대한 이상치를 계산하며, 최종적으로 임계값과의 비교를 통해 이상 여부를 예측한다. 성능 평가를 위해 시계열 이상 탐지를 위한 공개 데이터셋을 이용하여 공정하게 이상 탐지 성능을 비교하였으며, 실험 결과는 제안하는 정규화 흐름 기법이 시계열 이상 탐지 시스템에 활용될수 있는 잠재성을 시사한다.

• Journal of the Korean Institute of Intelligent Systems
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• v.11 no.9
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• pp.777-781
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• 2001

This paper presents an image contrast enhancement technique for improving the low contrast images using the improved IAFC(Integrated Adaptive Fuzzy Clustering) model. The low pictorial information of a low contrast image is due to the vagueness or fuzziness of the multivalued levels of brightness rather than randomness. Fuzzy image processing has three main stages, namely, image fuzzification, modification of membership values, and image defuzzification. Using a new model of automatic crossover point selection, optimal crossover point is selected automatically. The problem of crossover point selection can be considered as the two-category classification problem. The improved IAFC model is used to classify the image into two classes. The proposed method is applied to several experimental images with 256 gray levels and the results are compared with those of the histogram equalization technique. We utilized the index of fuzziness as a measure of image quality. The results show that the proposed method is better than the histogram equalization technique.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.11
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• pp.2429-2434
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• 2010

In this paper, we propose a method to extract and analyze palm line with fuzzy method. In order to extract the palm part, we transform the original RGB color space to YCbCr color space and extract sin colors ranging Y:65-255, Cb:25-255, Cr:130-255 and use it as a threshold. Possible noise is removed by 8-directional contour tracking algorithm and morphological characteristic of the palm. Then the edge is extracted from that noise-free image by stretching method and sobel mask Then the fuzzy binarization algorithm is applied to remove any minute noise so that we have only the palm lines and the boundary of the hand. Since the palm line reading is done with major lines, we use the morphological characteristics of the analyzable palm lines and fuzzy inference rules. Experiment verifies that the proposed method is better in visibility and thus more analyzable in palm reading than the old method.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.3
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• pp.549-557
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• 2016

It is important for effective visualization to summarize not only a large amount of debugging information but also the mental models of abstract ideas. This paper presents an abstract visualization tool which provides effective visualization of thread structure and race information for OpenMP programs with critical sections and nested parallelism, using a partial order execution graph which captures logical concurrency among threads. This tool is supported by an on-the-fly trace-filtering technique to reduce space complexity of visualization information, and a graph abstraction technique to reduce visual complexity of nested parallelism and critical sections in the filtered trace. The graph abstraction of partial-order relation and race information is effective for understanding program execution and detecting to eliminate races, because the user can examine control flow of program and locations of races in a structural fashion.

• Tunnel and Underground Space
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• v.19 no.2
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• pp.158-166
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• 2009

As a basic study for investigating the development of the stress-induced crack in Hoek-Brown rock, a homogenization technique of elastic cracks is proposed. The onset of crack is monitored by Hoek-Brown empirical criterion, while the orientation of the crack is determined by the critical plane approach. The concept of volume averaging in stress and strain component was invoked to homogenize the representative rock volume which consists of intact rock and cracks. The formulation results in the constitutive relations for the homogenized equivalent anisotropic material. The homogenization model was implemented in the standard FEM code COSMOSM. The numerical uniaxial tests were performed under plane strain condition to check the validity of the propose numerical model. The effect of friction between the loading plate and the rock sample on the mode of deformation and fracturing was examined by assuming two different contact conditions. The numerical simulation revealed that the homogenized model is able to capture the salient features of deformation and fracturing which are observed commonly in the uniaxial compression test.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.48 no.6
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• pp.82-90
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• 2011

This paper proposes an advanced outdoor localization algorithm of a GPS(global positioning system)-INS(inertial navigation system) integration system. In order to reduce noise from the internal INS sensors, discrete wavelet transform and variable threshold method are utilized. The UPF (unscented particle filter) combines GPS information and INS signals to implement precise outdoor localization algorithm and to reduce noise caused by the acceleration, deceleration, and unexpected slips. The conventional de-noising method is mainly carried out using a low pass filter and a high pass filter which essentially result in signal distortions. This newly proposed system utilizes the vibration information of actuator according to fluctuations of the velocity to minimize signal distortions. The UPF also resolves non-linearities of the actuator and non-normal distributions of noises. Effectiveness of the proposed algorithm has been verified through the real experiments and the results are demonstrated.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.497-498
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• 2017

기존의 영상 복원 방법에서는 영상에 퍼지 스트레칭 기법을 이용하여 명암 대비를 강조하였다. 강조된 영상에서 Max-Min 연산을 위해서 칼라 채널의 최대값을 이용하여 각 픽셀 값을 정규화 하였다. 정규화 된 픽셀 값에 Min 연산을 적용하여 연결 가중치를 계산하여 훼손된 영상의 복원에 적용하였다. 그러나 일부 손실된 영상에서 손실된 부분을 탐색하기 위해 $10{\times}10$을 가진 마스크를 이용하여 훼손된 영역을 탐색한 후, 탐색된 훼손된 영역에 연결 가중치를 적용하여 임계값보다 적은 경우에는 임계값으로 설정하여 손실된 부분을 복원하였으나 원 영상과의 차이가 나는 경우가 자주 발생하여 복원의 정확성이 낮아지는 문제점이 있다. 따라서 본 논문에서는 영상의 복원의 정확성을 높이기 위하여 그레이 영상뿐만 아니라 칼라 영상에서도 복원의 정확성을 높일 수 있는 방법을 제안한다. 제안된 방법을 다양한 칼라 영상을 대상으로 실험한 결과, 제안된 방법이 기존의 방법보다 복원의 정확성이 높아진 것을 확인할 수 있었다.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1998.03a
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• pp.145-148
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• 1998

본 논문은 뉴스 비디오 데이터베이스를 구축하기 위한 장면 분할 기법 중 Color Histogram에서 각각의 RGB를 따로 계산하여 차이값을 세부화하는 장점과, x2 Histogram에서 차이값을 강조하는 장점을 이용하여 NTSC표준에 따른 가중치를 적용한 새로운 장면 분할 방법을 제안하였다. 제안 알고리즘의 성능 평가를 위한 실험 도메인은 국내 KBS, MBC, SBS 방송의 뉴스 비디오와 국외 CNN, NHK의 뉴스 비디오를 택하였다. 주어진 환경내에서 제안한 방법을 기존의 Color Histogram, x2 Histogram, 그리고 Bin to bin difference (B2B)과의 실험결과와 비교하여 효율적임을 보였으며, 임계치의 자동선택 가능성을 제시 하였다.