• The Korean Journal of Applied Statistics
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• v.25 no.5
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• pp.733-741
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• 2012

The successful launch of Arirang satellites allow the acquisition of high resolution satellite imagery of Korean territory and enables the transition from the conventional cultivation area survey method to new image based methods adopted in advanced nations. In this study, we suggested reasonable sizes of the primary sampling unit and the secondary sampling unit for the satellite imagery based sampling design in 8 provinces preselected for this research. The PSU size was determined mainly in consideration of intracorrelation that shows the degree of homogeneity within each cluster and the efficiency of the image process. For the SSU size, we considered the relative standard error and the differences between the land cover maps produced by the Ministry of Environment and the satellite imagery processed by the National Statistical Office.

• The Korean Journal of Applied Statistics
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• v.25 no.5
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• pp.707-718
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• 2012

We propose a semi-parametric model to analyze clustered and interval-censored data; in addition, we plugged-in a gamma frailty to the model to measure the association of members within the same cluster. We propose an estimation procedure based on EM algorithm. Simulation results showed that our estimation procedure may result in unbiased estimates. The standard error is smaller than expected and provides conservative results to estimate the coverage rate; however, this trend gradually disappeared as the number of members in the same cluster increased. In addition, our proposed method was illustrated with data taken from diabetic retinopathy studies to evaluate the effectiveness of laser photocoagulation in delaying or preventing the onset of blindness in individuals with diabetic retinopathy.

• Rapid Communication in Photoscience
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• v.2 no.3
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• pp.72-75
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• 2013

Bulk nanobubble is one of the nanoscopic gaseous state found in the solution. We measured transient absorption spectra of eosin Y in the excited triplet state ($^3EY^{2-*}$) to elucidate differences in the dissipation process of the bulk nanobubble of oxygen molecule at air pressure. The time dependence of the oxygen dissipation process was classified three time domains (P1, P2 and P3). The comparison of ordinary bubbling method gave different results at P3 in contrast to similar results at P1 and P2, indicating the existence of characteristic dissolving state in the case of nanobubble.

• Journal of the Korean Society of Clothing and Textiles
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• v.26 no.11
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• pp.1638-1648
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• 2002

In this study, we classified adjectives to represent the image of clothing materials as the fundamental process for evaluation of the images on various fabrics and reviewed hierarchy and evaluation dimensions regarding the image of clothing materials. The adjectives to express the image of clothing materials were extracted from Fashion Magazine and Fashion Trend Book The similarity among adjectives was measured by pair-wise comparison without showing fabrics. From the result of the cluster analysis, 87 adjectives were finally extracted through the integrated processing of the adjectives with similar meaning and a close distance. Through the cluster analysis, the hierarchy of the clothing material images was examined. The clothing material images were classified into 12 primary sub-clusters such as ‘feminine', ‘warm', ‘neat', ‘classical', ‘pastoral.' ‘casual', ‘modern'. ‘ambiguous', ‘primitive', masculine', ‘abundant', and ‘arranged'. The dimensions evaluating the clothing material images were also developed using the multi-dimensional scaling method. A 4-dimensions and 8-axes system was established, which is composed of ‘masculine-feminine', ‘new-old', ‘casual-classical', and ‘ambiguous-arranged' images.

• Journal of Magnetics
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• v.18 no.2
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• pp.202-206
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• 2013

In this paper, the MFL (magnetic flux leakage) signals of complex defects on the underground gas pipeline are analyzed and their depths are estimated. Since closely-located defects (complex defects) affect each other, accelerate the progress of defection, and are finally combined to one (cluster), it's meaningful to differentiate complex defects from single defects by analyzing their characteristics. Various types of complex defects are characterized and analyzed by defining the safety distance for interference. 26 artificial defects are carved on the pipeline simulation facility (PSF) to analyze the characteristics of complex defect and demonstrate the accuracy of the proposed complex defect estimation. The proposed method shows average length error of 5.8 mm, average width error of 15.55 mm, and average depth error of 8.59%, respectively.

• Journal of The Korean Astronomical Society
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• v.31 no.2
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• pp.105-108
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• 1998

We have found that the two-point correlation function of the APM clusters of galaxies has an amplitude much higher than that claimed by the APM group. As the richness limit increases from R = 53 to 80, the correlation length increases from 17.5 to 28.9 $h^{-1}Mpc$. This indicates that the richness dependence of the APM cluster correlation function is also much stronger than what the APM group has reported. The richness dependence can be represented by a fitting formula ro = 0.53dc + 0.01, which is consistent with the Bahcall's formula ro = 0.4dc. We have tried to find the possible reason for discrepancies. However, our estimates for the APM cluster correlation function are found to be robust against variation of the method of calculation and of sample definition.

• Macromolecular Research
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• v.8 no.6
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• pp.292-297
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• 2000

The theoretical synthesis of the isotactic and syndiotactic poly(methyl methacrylate) were carried out as a model for real polymerization reactions following the normal chain reaction processes by repeating the uniform localization of wave functions with inclusion of the interaction between the end group of the cluster and an attaching molecule by the elongation method, and then, the calculated value was compared with the usual PM$_3$ calculation. The results revealed that a reaction of cluster with monomer molecules has made it possible to calculate the electronic structure and total energy of polymer with nearly infinite length and a matrix of constant dimension. The isotactic poly(methyl methacrylate) is more stable than syndiotactic one. The same tendency have been found between the experimentally measured properties and a calculated total energy to explain the chain motion in isotatic and syndiotactic poly(methyl methacrylate).

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.67 no.1
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• pp.47-51
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• 2018

This paper is concerned with an optimization design of Incremental Granular Model(IGM) based Genetic Algorithm (GA) as an evolutionary approach. The performance of IGM has been successfully demonstrated to various examples. However, the problem of IGM is that the same number of cluster in each context is determined. Also, fuzzification factor is set as typical value. In order to solve these problems, we develop a design method for optimizing the IGM to optimize the number of cluster centers in each context and the fuzzification factor. We perform energy analysis using 12 different building shapes simulated in Ecotect. The experimental results on energy efficiency data set of building revealed that the proposed GA-based IGM showed good performance in comparison with LR and IGM.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.1
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• pp.42.1-42.1
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• 2014

A gravitational weak-lensing map provides a weighted "picture" of the projected surface mass density and is to be an important tool for identifying "mass-selected" clusters of galaxies. However, weak-lensing maps have a limitation due to the projection of large-sclae structure along the line-of-sight. Geller et al. (2010) and Kurtz et al. (2012) compared massive clusters identified in a dense redshift survey with significant weak-lensing map convergence peaks. Both assessments of the efficiency of weak-lensing map for cluster identification did not draw a general conclusion, because the sample is so small. Thus, we additionally perform deep imaging observations of fields in a dense galaxy redshift survey that contain galaxy clusters at z~0.2-0.5, using CFHT Megacam. Our study will provide an important opportunity to examine the efficiency and completeness of a weak-lensing selection, and further to improve the method of cluster identification in future weak-lensing surveys.

• Journal of the Korean Data and Information Science Society
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• v.16 no.2
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• pp.217-226
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• 2005

Cluster analysis has been widely used in many applications, such as data analysis, pattern recognition, image processing, etc. But clustering requires many hours to get clusters that we want, because it is more primitive, explorative and we make many data an object of cluster analysis. In this paper we propose a new clustering method, 'Clustering algorithm using a center of gravity for grid-based sample'. It reduces running time by using grid-based sample and keeps accuracy by using representative point, a center of gravity.