• Title/Summary/Keyword: Fractal dimension

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The Estimation of the Extent of Weathering using Fractal Dimension through a Comparison with Chemical Characteristic (화학적 특성과의 비교 분석을 통한 프랙탈 차원을 이용한 풍화도 추정)

  • Noh, Soo-Kack;Son, Young-Hwan;Bong, Tae-Ho;Park, Jae-Sung
    • Journal of The Korean Society of Agricultural Engineers
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    • v.54 no.2
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    • pp.127-135
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    • 2012
  • The processes of chemical and physical weathering occur simultaneously. The objective of this study was to estimate the degree weathered using fractal dimension through comparison with chemical characteristic of soil samples from Pohang (PH) and Kimpo (KP). Comparing chemical characteristics with fractal dimension, $SiO_2$, $Na_2O$, $K_2O$ content decreased and loss of ignition increased as fractal dimension increased. And fractal dimension showed high correlation with CWI while ATI, STI CIW, PI, CIA and RR demonstrated different degrees of correlation with fractal dimension. The tendency of the changes in oxide content and chemical weathering index with increasing fractal dimension appeared to be similar with the chemical changes due to weathering. Therefore, fractal dimension could be a good indicator representing the extent of weathering and chemical changes.

Vowel Recognition Using the Fractal Dimensioin (프랙탈 차원을 이용한 모음인식)

  • 최철영
    • Proceedings of the Acoustical Society of Korea Conference
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    • 1994.06c
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    • pp.364-367
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    • 1994
  • In this paper, we carried out some experiments on the Korean vowel recognition using the fractal dimension of the speech signals. We chose the Mincowski-Bouligand dimensioni as the fractal dimension, and computed it using the morphological covering method. For our experiments, we used both the fractal dimension and the LPC cepstrum which is conventionally known to be one of the best parameters for speech recognition, and examined the usefulness of the fractal dimension. From the vowel recognition experiments under various consonant contexts, we achieved the vowel recognition error rats of 5.6% and 3.2% for the case with only LPC cepstrum and that with both LPC cepstrum and the fractal dimension, respectively. The results indicate that the incorporation of the fractal dimension with LPC cepstrum gies more than 40% reduction in recognition errors, and indicates that the fractal dimension is a useful feature parameter for speech recognition.

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Morphological. Analysis of Wear Particles by Fractal Dimension (차원해석에 의한 기계습동재료의 마멸분 형상특징 분석)

  • Won, D. W.;Jun, S. J.;Cho, Y. S.;Kim, D. H.;Park, H. S.
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2001.11a
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    • pp.53-58
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    • 2001
  • Fractal dimension is the method to measure the roughness and the irregularity of something that cannot be defined obviously by Euclidean dimension. And the analysis method of this dimension don't need perfect, accurate boundary and color like analysis lot diameter, perimeter, aspect or reflectivity of wear particles or surface. If we arranged the morphological characteristic of various wear particle by using the characteristic of fractal dimension, it might be very efficient to the diagnosis of driving condition. In order to describe morphology of various wear particle, the wear test was carried out under friction experimental conditions. And fractal descriptors was applied to boundary and surface of wear particle with image processing system. These descriptors to analyze shape and surface wear particle are boundary fractal dimension and surface fractal dimension.

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Estimation of Fractal Dimension According to Stream Order in the leemokjung Subbasin (이목정 소유역의 하천차수를 고려한 프랙탈 차원의 산정)

  • Go, Yeong-Chan
    • Journal of Korea Water Resources Association
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    • v.31 no.5
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    • pp.587-597
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    • 1998
  • Researchers have suggested that the fractal dimension of the stream length is uniform in all the streams of the basin and the estimates of the fractal dimension are in between 1.09 and 1.13 which may be considerably large values. In this study, the fractal dimension for the Ieemokjung subbasin streams in the Pyungchang River basin which is one of the IHP representative basins in Korea are estimated for each stream order using three scale maps of a 1/50,000, 1/25,000, and 1/5,000. As a result, the fractal dimension of the stream length is different by stream order and the fractal dimension of all streams shows a lower value in comparison to that of the previous studies. As a result of the fractal dimension estimation for the Ieemokjung subbasin streams, we found that the fractal dimension of the stream length shows different estimates in stream orders. The fractal dimension of 1st and 2nd order stream is 1.033, and the fractal dimension of 3rd and 4th order stream is 1.014. This result is different from the previous studies that the fractal dimension of the stream length is uniform in all streams of the basin. The fractal dimension for a whole stream length is about 1.027. Therefore, the previous estimates of 1.09 and 1.13 suggested as the fractal dimension of the stream length may be overestimated in comparison with estimated value in this study.

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Vowel Recognition Using the Fractal Dimension (프랙탈 차원을 이용한 모음인식)

  • 최철영;김형순;김재호;손경식
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.19 no.6
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    • pp.1140-1148
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    • 1994
  • In this paper, we carried out some experiments on the Korean vowel recognition using the fractal dimension of the speech signals. We chose the Minkowski-Bouligand dimension as the fractal dimension, and computed it using the morphological covering method. For our experiments, we used both the fractal dimension and the LPC cepstrum which is conventionally known to be one of the best parameters for speech recognition, and examined the usefulness of the fractal dimension. From the vowel recognition experiments under various consonant contexts, we achieved the vowel recognition error rates of 5.6% and 3.2% for the case with only LPC cepstrum and that with both LPC cepstrum and the fractal dimension, respectively. The results indicate that the incorporation of the fractal dimension with LPC cepstrum gives more than 40% reduction in recognition errors, and indicates that the fractal dimension is a useful feature parameter for speech recognition.

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Crack location in beams by data fusion of fractal dimension features of laser-measured operating deflection shapes

  • Bai, R.B.;Song, X.G.;Radzienski, M.;Cao, M.S.;Ostachowicz, W.;Wang, S.S.
    • Smart Structures and Systems
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    • v.13 no.6
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    • pp.975-991
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    • 2014
  • The objective of this study is to develop a reliable method for locating cracks in a beam using data fusion of fractal dimension features of operating deflection shapes. The Katz's fractal dimension curve of an operating deflection shape is used as a basic feature of damage. Like most available damage features, the Katz's fractal dimension curve has a notable limitation in characterizing damage: it is unresponsive to damage near the nodes of structural deformation responses, e.g., operating deflection shapes. To address this limitation, data fusion of Katz's fractal dimension curves of various operating deflection shapes is used to create a sophisticated fractal damage feature, the 'overall Katz's fractal dimension curve'. This overall Katz's fractal dimension curve has the distinctive capability of overcoming the nodal effect of operating deflection shapes so that it maximizes responsiveness to damage and reliability of damage localization. The method is applied to the detection of damage in numerical and experimental cases of cantilever beams with single/multiple cracks, with high-resolution operating deflection shapes acquired by a scanning laser vibrometer. Results show that the overall Katz's fractal dimension curve can locate single/multiple cracks in beams with significantly improved accuracy and reliability in comparison to the existing method. Data fusion of fractal dimension features of operating deflection shapes provides a viable strategy for identifying damage in beam-type structures, with robustness against node effects.

A Study on the Design of Fatigue Strength using Fractal Character of Surface Micro-crack (표면미소균열의 프랙탈 특성을 이용한 피로강도설계에 관한 연구)

  • Cho, Seok-Swoo;Joo, Won-Sik
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.12
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    • pp.143-151
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    • 1999
  • The shape of surface micro-crack is very irregular due to nonhomogeneous microstructure but is very important in respect to qualitative estimation of fatigue life. Fractal geomety can quantify the shape of surface mciro-crack. Fractal dimension is measured for surface micro-cracks with coast line and box counting method and estimates cycle ration in Al 2024-T3. The average fractal dimension $D_{favg}$ of surface micro-cracks has 3-parameter weibull distribution and location parameter is nearly constant but shape parameter decreases as cycle ration increases. The fractal dimension by coast line method is measured for individual surface micro-crack but the fractal dimension by box countin method is measured for all the surface micro-cracks under sampling area. Therefore, This paper shows fractal dimension $D_{fb}$ can predict cycle ratio $N/N_f$ more convenient than fractal dimension $D_{favg}$.

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Application of Fractal Parameter for Morphological Analysis of Wear Particle (마멸입자 형상분석을 위한 프랙탈 파라미터의 적용)

  • 조연상;류미라;김동호;박흥식
    • Tribology and Lubricants
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    • v.18 no.2
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    • pp.147-152
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    • 2002
  • The morphological analysis of wear particle is a very effective means fur machine condition monitoring and fault diagnosis. In order to describe morphology of various wear particle, the wear test was carried out under friction experimental conditions. And fractal descriptors was applied to boundary and surface of wear particle with image processing. These descriptors to analyze shape and surface of wear particle are shape fractal dimension and surface fractal dimension. The boundary fractal dimension can be derived from the boundary profile and surface fractal dimension can be determined by sum of intensity difference of surface pixel. The morphology of wear particles can be effectively obtained by two fractal parameter.

Application of Fractal Parameter for Morphological Analysis of Wear Particle (마멸입자 형상분석을 위한 프랙탈 파라미터의 적용)

  • 원두원;전성재;조연상;박흥식;전태옥
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2001.06a
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    • pp.30-35
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    • 2001
  • The morphological analysis of wear particle is a very effective means for machine condition monitoring and fault diagnosis. In order to describe morphology of various wear particle, the wear test was carried oui under friction experimental conditions. And fractal descriptors was applied to boundary and surface of wear particle with image processing system. These descriptors to analyze shape and surface wear particle are share fractal dimension and surface fractal dimension. The boundry fractal dimension can be derived from the boundary profile and surface fractal dimension can be determined b)r sum of intensity difference of surface pixel. The morphology of wear particles can be effectively obtained by two fractal dimensions.

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Application of Fractal Dimension for Morphological Analysis of Wear Particle (마멸입자 형태해석을 위한 Fractal 차원의 적용)

  • 오동석;조연상;서영백;박흥식;전태옥
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 1998.10a
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    • pp.115-123
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    • 1998
  • The morphological analysis of wear particle is a very effective means for machine condition monitoring and fault diagnosis. In order to describe morphology of various wear particle, the wear test was carried out under different experimental conditions. And fractal descriptors was applied to boundary and surface of wear particle with image processing system. These descriptors to analyze shape and surface wear particle are shape fractal dimension and surface fractal dimension. The shape fractal dimension can be derived from the boundary profile and surface fractal dimension can be determined by sum of intensity difference of surface pixel. The morphology of wear particles can be effectively obtained by two fractal dimensions.

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