• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.08a
• /
• pp.117-120
• /
• 2003

Fractal mathematics is being highlighted as a research method for classification of image. But the application of Fractal dimension(FD) 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(FD) 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.

• Journal of Ocean Engineering and Technology
• /
• v.14 no.1
• /
• pp.29-36
• /
• 2000

Surface micro-crack grows along intergranular or transgranular region of crystal grains. But if it meets the barrier such as sessile dislocation and precipitates it loses straightness and deflects. Investigators had many difficulties in estimating fatigue life of smooth specimen because of the random distribution growth and coalescence of surface micro-cracks. The path of surface micro-crack has irregularity due to nonhomogeneous microstructure. Euclidian geometry can't quantify the shape of surface micro-crack but fractal geometry can. Therefore in this paper fractal dimension is measured at various stage of cycle ratio and estimated cycle ratio in 2024-T3 aluminium, alloy.

• Journal of the Korean GEO-environmental Society
• /
• v.12 no.12
• /
• pp.79-88
• /
• 2011

Adfreeze bond strength develops upon freezing of pore water within soil and at foundation surface. It has been reported that various factors like temperature, soil type, and pile surface roughness affect adfreeze bond strength. Especially, pile surface roughness has been considered as a primary factor to design pile foundation in frozen ground. It has usually been estimated with fixed correction factors for pile materials. However, even if the pile foundation material is the same, the surface roughness could vary depending on the production circumstances. In this study, laboratory test was carried out to quantitatively analyze the effects of surface roughness on the adfreeze bond strength, and fractal dimension was used as a measure for surface roughness. Test results showed that adfreeze bond strength increased with decreasing temperature, increasing vertical stress and surface roughness. The adfreeze bond strength varies sensitively with surface roughness in the early freezing section of $-2^{\circ}C$, but its sensitivity decreased in the temperature ranging between $-2^{\circ}C$ to $-5^{\circ}C$. The results conclude that the roughness highly affects the frictional resistance of pile surface in frozen ground; however, the roughness does not affect considerably when the temperature drops below about $-2^{\circ}C$.

• Korean Journal of Remote Sensing
• /
• v.24 no.2
• /
• pp.125-131
• /
• 2008

Hyperspectral imaging is used in a wide variety of research since the image is obtained with a wider wavelength range and more bands than multispectral imaging. However, there are limitations, namely that each band has a shorter wavelength range, the computation cost is increased in the case of numerous bands, and a high correlation between each band and noise bands exists. The previous analysis method does not produce ideal results due to these limitations. Therefore, in the case of using the hyperspectral image, image analysis after eliminating noise bands is more accurate and efficient. In this study, noise band elimination of the hyperspectral image preprocessing is highlighted, and we use fractal dimension for noise band elimination. The Triangular Prism Method is used, being the typical fractal dimension method of the curved surface. The fractal dimension of each band is calculated. We then apply the Continuum Removal method to normalize. A total of 35 bands are estimated by noise band with a threshold value that is obtained empirically. The hyperion hyperstpectral image collected on the EO-1 satellite is used in this study. The result delineates that noise bands of the hyperion image are able to be eliminated with the fractal dimension and Continuum Removal method.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.16 no.9 s.100
• /
• pp.949-956
• /
• 2005

In this paper, a new CPW-fed cross shape fractal antenna having a self-affinity is presented. This novel configuration, which has anisotropic scaling symmetry, makes smaller profile characteristic compared to the fractal antenna using a self-similarity. Increase of the iteration coefficient, which leads to decrease of the fundamental resonant frequency, shows a good impedance matching condition and multi-band characteristics due to new surface current paths. The radiation patterns are similar to those of monopole antennas. In the K3 stage of iteration, the proposed antenna shows a measured maximum gain 2.27 dBi at 940 MHz. A commercially available software based on the FDTD algorithm has been used to obtain the predicted results. In addition, an RT/Duroid 5880 substrate has been employed for the experimental results.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.13 no.10
• /
• pp.834-839
• /
• 2000

The structural properties that SEM photograph of ZnO varistors surface studied by fractal mathematics program were investigated to verify the relations of electrical characteristics. The SEM photograph of ZnO varistors surface were changed by binary code and the grain shape of that were analyzed by fractal dimension. The void of ZnO varistors surface was found by fractal program. The relation between grain density and electrical properties depend on fractal dimension. The grain size in ZnO varistors surface was decreased by increasing of Sb$_2$O$_3$ addition. The spinel structure was formed by Sb$_2$O$_3$addition and it was depressed the ZnO grain formation. The grain size of ZnO by Sb$_2$O$_3$addition were from 5 to 10[${\mu}{\textrm}{m}$]. Among of ZnO varistors, fractal dimension of ZnO4 was very high as a 1.764. The density of grain boundary in ZnO2 and ZnO3 varistors surface was 15[%] by formed spinal structure. The breakdown electric field of ZnO2 that fractal dimension has 1.752 was very high to be 8.5[kV/cm]. When the fractal dimensin was high, the grain shape of ZnO varistors was complex and the serial layers of ZnO grain was increased.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1995.10a
• /
• pp.251-254
• /
• 1995

The quality and functionality of machined products is determined by surface finish. The surface roughness is characterized by roughness parameters such as R $_{a}$ and R $_{max}$. While such parameters are useful to define the quality of surface, they are nor sufficiently descriptive characteristics of surface. The fractal dimension which can describe characteristics od surface roughness than conventional roughness parameters has been applied. In this work, Relation between fractal dimension and surface roughness will be examined as a means of characterizing surface roughness.s.s.

• Journal of the Korean Applied Science and Technology
• /
• v.34 no.3
• /
• pp.525-535
• /
• 2017

In order to produce hydrophilic coating solution, which has superior antifogging and antifouling effect on the glass surface of solar cell module as well as improving photovoltaic efficiency, nanosilica was dispersed in an aqueous solution of Tween 20 and fluorosurfactant composed of decafluorobutane and polyethylene glycol. The antifogging effect at high temperature was excellent for all the coating solutions containing nanosilica, but the antifouling effect was observed when the content of nanosilica was over 6 wt%. As the content of fluorosurfactant increased, the initial water contact angle slightly increased and the antifogging effect remained well until 500 wiping with wet $Wipeol^{(R)}$. The antifouling effect was also excellent regardless of the content of fluorosurfactant, thus 0.1 wt% of the fluorosurfactant was enough for a coating solution production. From the AFM results, when 0.1 wt% to 0.3 wt% of the fluoro surfactant was added, the fractal structure of the coated glass surface was clearly existed and contributed to the better antifouling effect. The transmittance of coated glass surface was highest in TL-1 coating solution containing 0.1 wt% of fluorosurfactant, and the addition of fluorosurfactant in a larger amount than 0.1 wt% did not improve the transmittance. This result is in good agreement with the previous AFM result which shows a high surface roughness as well as a fractal structure formation for the TL-1 coating solution.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2009.10a
• /
• pp.33-37
• /
• 2009

Finite-element methods are used to study non-adhesive, frictionless rough contact of elastic and plastic solids. Roughness on spherical surfaces is realized by self-affine fractal. True contact area between the rough surfaces and flat rigid surfaces increases with power law under external normal loads. The power exponent is sensitive to surface roughness as well as the curvature of spherical geometry. Surface contact pressures are analyzed and compared for the elastic and plastic solids. Distributions of local contact pressure are shown dependent on the surface roughness and the yield stress of plastic solids.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2002.05b
• /
• pp.107-110
• /
• 2002

The optical memory devices of BST thin films to composite $(Ba_{0.7}\;Sr_{0.3})TiO_{3}$ using sol-gel method were fabricated by changing of the depositing layer number on $Pt/Ti/SiO_{2}/Si$ substrate. The structural properties of optical memory devices to be ferroelectric was investigated by fractal analysis and 3-dimension image processing. The thickness of BST thin films at each coating numbers 3, 4 and 5 times was $2500[\AA]$, $3500[\AA]$ and $3800[\AA]$. BST thin films exhibited the most pronounced grain growth. The surface morphology image was roughness with coating numbers. The thin films increasing with coating numbers shows a more textured and complex configuration.