• Journal of the Korea Furniture Society
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• v.21 no.6
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• pp.449-458
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• 2010

This study attempted to investigate the effect of panel thickness on the horizontal density distribution (HDD) of medium density fiberboard (MDF) in a destructive way. Full size MDF panels with five different thicknesses such as 2 mm, 4.5 mm, 9 mm, 18 mm and 30 mm were cut into two different specimen sizes, i.e., $500{\times}500\;mm$ and $120{\times}120\;mm$ to measure the HDD. In general, the overall density of MDF panel diminished as the thickness increased, showing the highest density for the thinnest MDF panels. The HDD variation was significant for the samples of smaller specimen size ($120{\times}120\;mm$). MDF panel thickness significantly influenced to the HDD, which increased as the thickness decreased. In addition, the thinner panels showed much wider range in the HDD than those of thicker panels. The coefficient of variation (COV) of HDD also followed a similar trend to the panel density as the thickness increased. In summary, MDF panel thickness had a significant impact on the HDD within a panel. The sample size also showed a considerable effect to the HDD of MDF panels.

• Journal of The Geomorphological Association of Korea
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• v.18 no.4
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• pp.213-221
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• 2011

The purpose of this study is to clarify the characteristics of forms and distributions of Gapyoungchon potholes. Different sizes of 153 potholes were distributed in the upper stream marginal area that was 30×25m, and over 70 percent among them were egg-shaped potholes. A development of joint in pothole was not important to make potholes in the stream but the mean size of potholes with joint was larger than without joint. Moreover, the schistosity structure of the bedrock was more important factor to develop potholes in this area. Finally, four cross sectional faces were found in this study area. From the reason, Gapyoungchon potholes are distributed on the rock terraces.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.13 no.3
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• pp.204-215
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• 1988

This paper deals with the adaptive state estimation which is designed specially for a tracking system containing unknown and/or radomly varying hybride noises to provide an accurate estimate of the system state. The range of discrete vectyor v in finite numbers(N) for this adaptive estimator span the entire possible range of impulse noise levels such as the binomial, the edge, the Tchebyscheff, the binomal-edge and the Tchbyscheff-edge distribution. A feed forward path consisting of zero detector and data selector is incoporated with the conventional adaptive state estimator so as to provide accurate estimations. Despite the large and randomly varying hybrid noises, results of computer simulations for the various discrete vector levels show that this adptive state estimator is turned out to be a good system with relatively small implse errors.

• Korean Journal of Ecology and Environment
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• v.37 no.3 s.108
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• pp.297-303
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• 2004

Two dimensional cellular automaton (CA) models were developed to investigate growth of biofilms in aquatic ecosystems. Simple local rules on CA were applied to governing growth of bacterial populations in relation to different nutrient concentrations. Initial bacterial distribution played an important role in determining population size and morphology of biofilm at low concentrations of nutrition. With clumped distribution, population size increased slowly compared with uniform and random distributions, while the porosity tented to be higher with uniform distribution compared with other initial distributions.

• The Korean Journal of Applied Statistics
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• v.28 no.3
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• pp.573-581
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• 2015

We study problems of sample size determination for one-sample location tests. A simulation study shows that sample size calculations based on approximated distribution do not achieve the nominal level of power. We investigate sample size determinations based on exact distribution and with a power that attains the nominal level.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2001.11a
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• pp.435-436
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• 2001

대기 중 에어로졸 입자의 크기 분포를 측정하는 기기 중 광학적 입자 계수기(Optical Particle Counter)는 0.3$\mu\textrm{m}$에서 25$\mu\textrm{m}$ 사이의 입자의 크기를 개개의 입자에 대한 산란광의 강도를 측정하여 그 강도와 미리 정해진 강도와의 관계에 의해 입자의 크기를 추정한다(Chun et al., 2001). 본 연구에서는 2001년 4월 제주 고산에서 실시된 ACE-Asia(Asian Pacific Regional Aerosol Characterization Experiment) 집중 관측 기간 중 광학적 입자 계수기(Optical Particle Counter; HIAC/ROYCO 5230)를 이용하여 측정한 이 기간 중 에어로졸 입자의 크기 분포의 특성을 황사시와 비황사시, 그리고 강수시와 비강수시로 나누고 그 특징을 비교하여 보았다. (중략)

• Korean Journal of Optics and Photonics
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• v.19 no.1
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• pp.43-47
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• 2008

Nowadays, the pattern size of BLU (Back Light Unit) adopted in TFT-LCD (Thin Film Transistor Liquid Crystal Display) is typically a few tens of micrometers. However, recently, researches on the TFT-LCD output characteristics depending on various types of BLU patterns are being performed in order to improve the output and uniformity. In this study, we analyzed the influence of pattern size, distribution, and areal ratio on the output characteristics.

• Journal of Life Science
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• v.7 no.4
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• pp.355-357
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• 1997

Seed size is a important yield components in soybean (Glycine max L.). The seed size frequency distributions in the mating between two G. max parents possessing quite different seed size exhibited a continuous distribution in the F$_{2}$ and F$_{3}$ generations. A progeny seed size equal to that of either parent was not observed in either generation. The population mean seed size in each generation was less than the mid-parent, with the distribution of lines skewed toward the small seeded parent.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10a
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• pp.109-111
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• 2001

공간데이터베이스에서 공간 질의를 최적화하기 위해서는 질의 결과 크기를 계산하는 것이 필수적이다. 그러나 공간 데이터베이스의 크기는 매우 방대하여 질의 결과 크기를 계산하는데 비용이 많이 든다. 이러한 문제를 해결하기 위해서는 실제 공간 데이터의 분포와 특성에 근접하도록 공간 데이터의 분포를 요약하여 이를 토대로 질의 결과 크기를 추정하는 것이 효과적이라 할 수 있다. 공간 분할 방법에는 균등분할 방법과 비균등 분할 방법이 있으면, 본 논문에서 제안한 방법은 1차원 데이터에 대한 선택률 추정기법 중에서 그 성능이 가장 우수하다고 평가된 바 있는 최대 면적 차이 분말을 공간 데이터베이스에 적용하여 공간 분할하는 것이다. 공간 데이터베이스에서 선택을 추정 방법은 공간 분할 방법에 따라 성능상의 차이가 있으며 본 논문은 기존의 방법과 제안한 방법을 실험을 통하여 선택률 추정의 정확성을 비교, 평가하여 제안한 방법이 우수함을 보였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.4
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• pp.319-324
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• 2016

Soils with various particle sizes generally show good shear strength. Some soils have a relatively strong resistance to shear failure in spite of narrow particle distribution, such as gap grading. Based on this example, it can be inferred that appropriate arrangements of particle size in soils might result in an increase in shear strength. This study investigates the strength variation of soils with respect to the particle size distribution. Gap, well, and uniform graded soils were prepared with a desired ratio, and a wide range of direct shear tests were done using the prepared samples. The test results show that there is a strong relationship between the particle size ratio and internal frictional angle. Gap graded soil has a greater frictional angle than a well-graded sample, even when specimens have the same maximum particle size, which is also the case for the uniform grade specimen. The results have potential for developing a methodology for stronger soils through a simple manipulation of particle size distribution.