• 자연과학논문집
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• 제4권
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• pp.191-220
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• 1991

Human Visual System(HVS)의 특성과 image의 textural regions의 roughness을 이용하여 image segmentation을 행하여 high compression에서도 고화질을 나타내는 새로운 image coder를 이 논문에서 논한다. 제안된 image coder는 constant segments를 가진 segmentation-based image coding technique의 문제들을 다음과 같은 방법론을 제안함으로써 해결하였다. Image를 HVS으로 보았을 때 degree of roughness에 관하여 textually homogeneous regions으로 segmentation하였다. Fractal dimension을 roughness of textural regions을 측정하기 위하여 사용하였다. Segmentation은 fractal dimension을 thresholding하여 textural regions이 three texture classes로 분류하였다(perceived constant intensity, smooth texture, and rough texture). High compression을 가지는 고질화의 image coder는 각각의 segment boundary와 각각의 texture class에 효율적인 coding technique를 적용 함으로 얻었다.

• 한국물환경학회지
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• 제26권2호
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• pp.343-348
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• 2010

The objective of this study was to investigate the effects of starvation periods with aerobic or non-aerobic conditions on the organic removal efficiencies and physical characteristics of activated sludge for treating saline and non-saline wastewater. During the experiment, MLSS, MLVSS, sludge volume index (SVI), floc size and fractal dimension, $COD_{Mn}$ removal efficiencies were monitored. The reductions of MLSS, MLVSS and SVI with maintaining the sludge under a non-aerobic condition during starvation periods were smaller than those under a aerobic condition. Floc size, fractal dimension and $COD_{Mn}$ removal efficiencies were less decreased under non-aerobic condition than under aerobic condition. And SVI were strongly correlated with floc size and fractal dimension. Consequently, the result showed that maintaining the activated sludge under non-aerobic starvation conditions was better strategy than that under aerobic starvation conditions as it adapted and resisted to starvation.

• 한국정밀공학회지
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• 제15권12호
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• pp.226-235
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• 1998

This study proposes the analysis and evaluation of method of time series of ultrasonic signal using the chaotic feature extraction for ultrasonic pattern recognition. The features are extracted from time series data for analysis of weld defects quantitatively. For this purpose, analysis objectives in this study are fractal dimension, Lyapunov exponent, and strange attractor on hyperspace. The Lyapunov exponent is a measure of rate in which phase space diverges nearby trajectories. Chaotic trajectories have at least one positive Lyapunov exponent, and the fractal dimension appears as a metric space such as the phase space trajectory of a dynamical system. In experiment, fractal(correlation) dimensions and Lyapunov exponents show the mean value of 4.663, and 0.093 relatively in case of learning, while the mean value of 4.926, and 0.090 in case of testing in slag inclusion(weld defects) are shown. Therefore, the proposed chaotic feature extraction can be enhancement of precision rate for ultrasonic pattern recognition in defecting signals of weld zone, such as slag inclusion.

• 자연과학논문집
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• 제7권
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• pp.67-73
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• 1995

본 논문에서는 인간시각 시스템의 특성을 이용하여 세그멘테이션을 행하는 새로운 텍스처 세그멘테이션 영상코딩 기술을 제안한다. 제안된 방법은 영상을 HVS가 인지한 러프니스 정도에 관하여 영상을 텍스처와 같은 성질의 영역으로 세그멘테이션하는 방법론을 제안하여 상 세그멘트를 갖는 세그멘테이션 영상코딩기술의 문제점을 해결한다. 세그멘테이션은 텍스처 영역을 3 가지의 다른 텍스처 크래스(인간이 인지한 상 인테셔티, 부드러운 텍스처 및 거칠은 텍스처)로 구분하기 위해서 프락탈 디멘션을 임계하여 얻는다. 프락탈 디멘션을 근사하기 위한 적당한 브락 크기를 결정하는 것이 중요하다. 좋은 화질을 갖는 재생 영상은 여러 종류의 영상에 대해서 약 0.1에서 0.25 비트/픽셀에서 얻는다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권12호
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• pp.5955-5977
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• 2018

Performance of the interpolation algorithm used in the technique of bi-dimensional empirical mode decomposition directly affects its popularization and application, so that the researchers pay more attention to the algorithm reasonable, accurate and fast. However, it has been a lack of an adaptive interpolation algorithm that is relatively satisfactory for the bi-dimensional empirical mode decomposition (BEMD) and is derived from the image characteristics. In view of this, this paper proposes an image interpolation algorithm based on the particle swarm and fractal. Its procedure includes: to analyze the given image by using the fractal brown function, to pick up the feature quantity from the image, and then to operate the adaptive image interpolation in terms of the obtained feature quantity. All parameters involved in the interpolation process are determined by using the particle swarm optimization algorithm. The presented interpolation algorithm can solve those problems of low efficiency and poor precision in the interpolation operation of bi-dimensional empirical mode decomposition and can also result in accurate and reliable bi-dimensional intrinsic modal functions with higher speed in the decomposition of the image. It lays the foundation for the further popularization and application of the bi-dimensional empirical mode decomposition algorithm.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 추계학술대회 논문집 전기물성,응용부문
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• pp.25-28
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• 2003

Fractal mathematics is being highlighted as a research method for classification of image. But the application of Fractal dimension(FB) has been required the complicated calculation method because of its complex repetition progressing. In this paper, it has been developed the new approach method to express the Fractal Dimension(FB) for aging level calculation and estimation system of outside insulator using special image processing algorithm. As a result after FD testing, the recognized aging estimation of FD has a very characteristics compared to the conventional visual inspection.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1994년도 추계학술대회
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• pp.169-171
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• 1994

This paper is to find out more reliable analyzing method of heart rate variability. Heart rate variability analysis is to evaluate cardiovascular stability and also have used as an indicator of autonomic nervous system activity. In this study, time domain analysis, spectral analysis and state space analysis method are applied to analyze heart rate variability. Because of nonlinear characteristics of heart rate, we need not only spectral analysis, but also state space analysis. Fractal dimension of spectral estimation is useful indicator of autonomic nervous activity.

• 한국대기환경학회지
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• 제15권2호
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• pp.175-182
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• 1999

Scanning electron microscopy (SEM) has played an important role in receptor modeling area because it is a powerful tool for characterizing individual particles. The purpose of the study was to classify individual diesel particles base on statistical analysis and image analysis by SEM/EDX (energy dispersive x-ray analyser). The diesel particles were sampled by both a modified CVS 75 mode and a high speed mode with a chassis dynamometer. The SEM/EDX system provides various physical parameters including particle's particle diameter and chemical information. Thus density and mass of the diesel particle were estimated cased on its chemical composition and further fractal dimensions of the diesel particle were obtained by the Hurst exponent method. The fractal dimension in the sample of modified CVS 75 mode was higher than the high speed mode. Finally, mass fractions for a diesel vehicle as a source profile were estimated cased on a particle class concept.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.105.6-105
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• 2001

Fish schools behave like a single organism and offer a considerable survival advantage. In our simulations, the fish school is well organized and behaves like a single creature depending solely on the interactions among individuals without having any director fish. This kind of system can be said as the typical one of "Complex Systems". We make clear the validity of fractal analyses to evaluate fish school movements through evaluation of both the simulated movements and the real sardine movements taken by video tape. The analyses showed that we need two kinds of fractal dimensions (D$_1$, D$_2$) to fit to the observations; the one(D$_1$) corresponds to smaller coarsening levels and D$_2$ does to larger coarsening levels. The double linear analyses in ...

• 한국통신학회논문지
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• 제21권3호
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• pp.587-599
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• 1996

In general fractal imge compression, each range block is approximated by a contractive transform of the matching domain block under the mean squared error criterion. In this paper, a distortion measure reflecting the properties of human visual system is defined and applied to a fractal image compression. the perceptual distortion measure is obtained by multiplying the mean square error and the noise sensitivity modeled by using the background brightness and spatial masking. In order to compare the performance of the mean squared error and perceptual distortion measure, a simulation is carried out by using the 512*512 Lena and papper gray image. Compared to the results, 6%-10% compression ratio improvements under improvements under the same image quality are achieved in the perceptual distortion measure.