• Journal of the Korean Electrochemical Society
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• v.13 no.1
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• pp.40-44
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• 2010

In this work, highly uniform size-controlled $Cu_2O$ nanocubes can be successfully formed by means of pulse electrodeposition. The size distribution, crystal structure, and chemical state of deposited $Cu_2O$ nanocubes are characterized using scanning electron microscopy, transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The phase transition from $Cu_2O$ to Cu can be controlled by constant current electrodeposition as a function of deposition time. In particular, the size of the $Cu_2O$ nanocubes can be controlled using pulse electrodeposition as a function of applied current density.

• Journal of the Korean Data and Information Science Society
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• v.21 no.1
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• pp.51-59
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• 2010

In the case that the regression function has a discontinuity point in generalized linear model, Huh (2009) estimated the location and jump size using the log-likelihood weighted the one-sided kernel function. In this paper, we consider estimation of the unknown number of the discontinuity points in the regression function. The proposed algorithm is based on testing of the existence of a discontinuity point coming from the asymptotic distribution of the estimated jump size described in Huh (2009). The finite sample performance is illustrated by simulated example.

• Communications for Statistical Applications and Methods
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• v.15 no.5
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• pp.709-717
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• 2008

The difference of two one-sided kernel estimators is usually used to detect the location of the discontinuity points of regression function. The large absolute value of the statistic imply discontinuity of regression function, so we may use the difference of two one-sided kernel estimators as the test statistic for testing null hypothesis of a smooth regression function. The problem is, however, we only know the asymptotic distribution of the test statistic under $H_0$ and we hardly expect the good performance of test if we rely solely on the asymptotic distribution for determining the critical points. In this paper, we show that if we adjust the bias of test statistic properly, the asymptotic rules hold for even small sample size situation.

• Structural Engineering and Mechanics
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• v.69 no.6
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• pp.637-649
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• 2019

In the current research paper, a quasi-3D beam theory is developed for free vibration analysis of functionally graded microbeams. The volume fractions of metal and ceramic are assumed to be distributed through a beam thickness by three functions, power function, symmetric power function and sigmoid law distribution. The modified coupled stress theory is used to incorporate size dependency of micobeam. The equation of motion is derived by using Hamilton's principle, however, Navier type solution method is used to obtain frequencies. Numerical results show the effects of the function distribution, power index and material scale parameter on fundamental frequencies of microbeams. This model provides designers with guidance to select the proper distributions and functions.

• Journal of the Korean Applied Science and Technology
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• v.23 no.1
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• pp.1-11
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• 2006

The W/O emulsion was formed by mixing hydrophobic nonion surfactants of span 80 and tween 60 with kerosine, and by adding sodium silicate aqueous solution. Precipitating the W/O emulsion by sodium bicarbonate resulted in spherical silica particles. Shape and size distribution of silica particles were observed. The particles were spherical and they have narrow size distribution. Particle sizes were 9.29, 7.39 and $5.73\;{\mu}m$ at homogenizer speed of 2500, 3000, and 3500 rpm, respectively. The particle size was decreased by increasing agitation speed due to the formation of emulsion droplet. At fixed agitation speed, absorbed paraffin oil weight were measured and the $SiO_2/Na_2O$ mole ratio effects on particle size were investigated. Particle size was decreased by increasing the mole ratio of $SiO_2/Na_2O$.

• Journal of the Korean Vacuum Society
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• v.10 no.2
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• pp.275-281
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• 2001

We used the discrete-sectional model to analyze the particle growth by coagulation of particles in silane plasma reactor, considering the Gaussian distribution function for particle charges. The effects of process conditions such as monomer size and mass generation rate of monomers on particle growth in plasma reactor were analyzed theoretically/ Based on the Gaussian distribution function of particle charges, the large particles of more than 40 nm in size are almost found to be charged negatively, but some fractions of small, tiny particles are in neutral state or even charged positively. As the particle size and surface area increase with time by particle coagulation, the number of charges per particle increases with time. As the large particles are generated by particle coagulation, the particle size distribution become bimodal. The results of discrete-sectional model for the particle growth in silane plasma reactor were in close agreement with the experimental results by Shiratani et al. [3] for the same plasma conditions. We believe the model equations for the particle charge distribution and coagulation between particles can be applied to understand the nano-sized particle growth in plasma reactor.

• Journal of Korean Society for Atmospheric Environment
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• v.17 no.E1
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• pp.1-7
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• 2001

The elemental characteristics of atmospheric aerosols were investigated as a function of particle size and water solubility. The aerosol particles were samples at 12 individual size ranges between 0.01 and 30㎛. Collected aerosol particles were separated into both soluble and insoluble components. The concentrations of 15 elements in both components were determined by a PIXE analysis using a 2.0 MeV-proton beam. In general, the mass size distribution of particulate matter was represented as a bimodal distribution. The maximum rations of S in July and December were 5.5 and 3.8 %, and they appeared in the size range of 0.47∼1.17㎛(stage No. 6 or 7) . The ratios of a S at non-separated size were 3.1 and 2.2 % in July and December, respectively, On the other hand, the maximum rations of Si in July and December were 7.0 and 5.4% and they appeared in the size range of 5.1∼30㎛(stage No. 0∼2). The ratios of Si at the non-separated size were 2.1 and 1.8% in July and December, respectively, The mass diameter of 12 elements ranged between 0.59㎛ of S and 3.20 of Fe. More than 90% of atmospheric aerosols consisted of the light elements such as C, N, O, H and Al. The soluble component was dominant in the smaller size range and the insoluble component in the larger size range. Large portions of Si. Ti and Fe existed in insoluble state. By contrast, S, Cl, Ca, Zn and Br were dissolved in water.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 1995.04a
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• pp.37-37
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• 1995

• Journal of the Korea Society of Computer and Information
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• v.25 no.6
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• pp.119-129
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• 2020

Software development activities are influenced by stochastic theory rather than deterministic one due to having process variability. Stochastic methods factor in the uncertainties associated with project activities and provides insight into the expected project outputs as probability distributions rather than as deterministic approximations. Thus, successful software projects systematically manage and balance five objectives based on historical probability: scope, size, cost, effort, schedule, and quality. Although software size estimation having much uncertainty in initial development has traditionally performed using deterministic methods: LOC(Lines Of Code), COCOMO(COnsructive COst MOdel), FP(Function Point), SLIM(Software LIfecycle Management). This research aims to present a function point method based on stochastic distribution and a case study based on Monte Carlo Simulation applying on an automotive electrical and electronics system software development. It is expected that the result of this paper is used as guidance for establishing of function point method in organizations and tools for helping project managers make decisions correctly.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1493-1510
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• 2000

Theoretical models that can be used to predict the range of main lobe widths and the probability distribution of the peak sidelobe levels of two-dimensionally sparse arrays are presented here. The arrays are considered to comprise microphones that are randomly positioned on a segmented grid of a given size. First, approximate expressions for the expected squared magnitude of the aperture smoothing function and the variance of the squared magnitude of the aperture smoothing function about this mean are formulated for the random arrays considered in the present study. By using the variance function, the mean value and the lower end of the range i.e., the first I percent of the mainlobe distribution can be predicted with reasonable accuracy. To predict the probability distribution of the peak sidelobe levels, distributions of levels are modeled by a Weibull distribution at each peak in the sidelobe region of the expected squared magnitude of the aperture smoothing function. The two parameters of the Weibull distribution are estimated from the means and variances of the levels at the corresponding locations. Next, the probability distribution of the peak sidelobe levels are assumed to be determined by a procedure in which the peak sidelobe level is determined as the maximum among a finite number of independent random sidelobe levels. It is found that the model obtained from the above approach predicts the probability density function of the peak sidelobe level distribution reasonably well for the various combinations of two different numbers of microphones and grid sizes tested in the present study. The application of these models to the design of random, sparse arrays having specified performance levels is also discussed.