• Korean Chemical Engineering Research
• /
• v.60 no.2
• /
• pp.260-266
• /
• 2022

Average aggregate size in particulate suspensions is estimated with scaling theories based on fractal concept and elasticity of colloidal gel. The scaling theories are used to determine structure parameters of the aggregates, i.e., fractal dimension and power-law exponent for aggregate size reduction with shear stress using scaling behavior of elastic modulus and shear yield stress as a function of particle concentration. The structure parameters are utilized to predict aggregate size which varies with shear stress through rheological modeling. Experimentally rheological measurement is conducted for aqueous suspension of zinc oxide particles with average diameter of 110 nm. The predicted aggregate size is about 1135 nm at 1 s^-1 and 739 nm at 1000 s^-1 on the average over the particle concentrations. It has been found that the predicted aggregate size near 0.1 s^-1 agrees with that the measured one by a dynamic light scattering analyzer operated un-sheared.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.15 no.7 s.100
• /
• pp.781-787
• /
• 2005

The correlation dimension can provide some intrinsic Information of an underlying dynamic system by reconstructing measured nonlinear time series. The vibration signals measured from a rotor with different clearance sizes between shaft and bushing were analyzed using the correlation dimension. The results showed that the correlation dimension can identify the size of the clearance of a rotor and the lubricating condition, which can not be analyzed by frequency spectrum or wavelet. The magnitude of the correlation dimension became smaller as the clearance larger and as the lubrication condition better.

• Journal of Korean Society on Water Environment
• /
• v.16 no.4
• /
• pp.459-468
• /
• 2000

This study is to investigate the floc structure and removal of turbidity and organic matter by PACI coagulation. The turbidity removal by PACI coagulation was obtained at larger pH range than alum coagulation. And the removal of organic matter was obtained at smaller pH range than that of turbidity. The organic matter was removed by the adsorption of $Al(OH)_3$ precipitates. Floc structure was characterized by measuring fractal dimension and volume diameter using AIA and SALLS. Fractal dimension measured by AIA did not show the different characteristics of floc produced in sweep floe and charge neutralization region. Using SALLS, floes in sweep floc region were found to be larger size and fractal dimension than flocs in charge neutralization region. As pollutant removal increased. larger fractal dimension and size of floc were measured. SALLS method was found to be more useful method to characterize flocs in coagulation than AIA method.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1992.04a
• /
• pp.153-156
• /
• 1992

디지탈 영상처리는 60년대 초부터 사용되어 왔으며 많은 양의 DATA를 처리해야 한다는 점과 일반적으로 적용될 수 있도록 충분히 빠르고 안정된 Algorithm이 요구된다는 점에서 상당히 느리게 발전되어 왔으며, 70년대에 들어서 Computer Vision이라는 학문이 상당한 연구과제로 부각되어 2 Dimension의 해석 및 인식을 위한 Algorithm들이 각종 자료를 통하여 발표되었고 80년대에 들어서부터 3 Dimension의 인식을 위한 Algorithme들이 연구과제로 진행되고 있다. 본 프로잭트는 그동안 국내에서 어려웠던 브라운관의 Crack 및 Size 감지의 경우 99.8%의 자동감지 효과를 구현하였다.

• Journal of Korean Society of Environmental Engineers
• /
• v.22 no.7
• /
• pp.1263-1271
• /
• 2000

This study investigated the floc structure and removal of turbidity and organic matter by alum coagulation. Results of this study indicated that sweep floc and charge neutralization area were shifted to more acidic region than that in the Amirtharajah's diagram. This was caused by organic matter present in the raw water. Removal regions of turbidity and organic matter were generally overlapped. However, organic matters was removed better at lower pH than turbidity. Floc structure was characterized by measuring fractal dimension and volume diameter using AIA and SALLS. SALLS method was found to be more reliable than AIA method. Floes in sweep floc region had larger size and fractal dimension than flocs in charge neutralization region. As pollutant removal increased, larger fractal dimension and size of floc were measured.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.23 no.1
• /
• pp.145-149
• /
• 2023

High-resolution images of surfaces provide detailed information on pores or shapes with specific sizes ranging from nano sizes to micrometers. However, it is not yet clear to determine an efficient association for pores or shapes from high-resolution images of surfaces. For the efficient association of pores and shapes, the surface characteristics of the device were considered as fractal dimensions by taking SEM photographs and binarizing the images. The fractal program was directly coded for surface analysis of the device. The device surface characteristics and electrical characteristics are thought to be related to the fractal dimension. The fractal dimension decreased with an increase in internal pores. The density and grain boundary of particles, which are structural characteristics of the device surface, were related to the fractal dimension. The particle size decreased with an increase in the fractal dimension and was uniformly formed. When the particles were uniformly formed, fewer pores were present and the fractal dimension increased.

• Journal of the Korean Institute of Educational Facilities
• /
• v.10 no.5
• /
• pp.5-14
• /
• 2003

The purpose of this survey study is to analyse the playground dimension of elementary school. To complete this mission, it is necessary to drive out elementary school have a lower dimension standard of playground through literal survey. Then, questionnaire and observation survey have been performed to teachers majored in physical education and these are focused on playground dimensions. The field survey study will provide the basic data for calculating proper playground dimensions and design source for planning space program of the school. The result of this survey study are as follows ; First, The Area of 'Gyo-ghi' is decreasing, and the land area of being used for 'Gyo-sa' is increasing. So the area of playground is decreasing. Second, The respondents require a playground size enough to contain 100m running track for testing the physical ability of students. But it is not possible to do so in current domestic condition, it is necessary to revise of the standard of physical test or enact a new one. Third, to solve the problems deviating from the playground size, the respondent suggests that set up a new gym or variable-size playgrounds rather than a large one Fourth, because playground has so much functions as rest, playing, walking and jogging etc besides physical education, it is necessary to consider the spaces for rest and play, when plan a tower-type school or small school.

• Proceedings of the Korean Institute of Interior Design Conference
• /
• 2006.05a
• /
• pp.229-233
• /
• 2006

The purpose of this study is to propose the standards for dimension system for unit space of the classroom in elementary school. The curriculum of elementary school has changed. It has been reflected the architectural plan of classroom of the nationwide elementary school. However the Ministry of Education repealed the statue about the facilities of the schools on September in 1997 and the new education curriculum -the 7th curriculum- demands various activities in the classroom. So we need to another size of unit space of the classroom in elementary school because the size of unit space will affect the quality of education. This study represents that the size of unit plan is based on the size of human body, education curriculum, established day, the number limit of classroom and teaching tools. In this study, regression analysis is used to find out a part of the body-size of Korean.

• Journal of Institute of Control, Robotics and Systems
• /
• v.22 no.9
• /
• pp.710-715
• /
• 2016

Due to its simplicity and high reliability, the box-counting(BC) method is one of the most frequently used techniques to estimate the fractal dimensions of a binary image with a self-similarity property. The fractal calculation requires data sampling that determines the size of boxes to be sampled from the given image and directly affects the accuracy of the fractal dimension estimation. There are three non-overlapping regular grid methods: geometric-step method, arithmetic-step method and divisor-step method. These methods have some drawbacks when the image size M becomes large. This paper presents a BC algorithm for enhancing the accuracy of the fractal dimension estimation based on a new sampling method. Instead of using the geometric-step method, the new sampling method, called the coverage ratio-step method, selects the number of steps according to the coverage ratio. A set of experiments using well-known fractal images showed that the proposed method outperforms the existing BC method and the triangular BC method.

• The Journal of Natural Sciences
• /
• v.7
• /
• pp.67-73
• /
• 1995

In this paper, a new texture segmentation-based image coding technique which performs segmentation based on properties of the human visual system (HVS) is presented. This method solves the problems of a segmentation-based image coding technique with constant segments by proposing a methodology for segmenting an image into texturally homogeneous regions with respect to the degree of roughness as perceived by the HVS. The segmentation is accomplished by thresholding the fractal dimension so that textural regions are classified into three texture classes; perceived constant intensity, smooth texture, and rough texture. It is very important to determine the proper block size for estimating the fractal dimension. Good quality reconstructed images are obtained with about 0.1 to 0.25 bit per pixel (bpp) for many different types of imagery.