• 동굴
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• 제71호
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• pp.5-11
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• 2006

A theoretical investigation of the solid phase mechanochemical synthesis of nano sized target product on the basis of dilution of the initial powdered reagent mixture by another product of an exchange reaction is presented. On the basis of the proposed 3 mode particle size distribution in mechanically activated mixture, optimal molar ratios of the components in mixture are calculated, providing the occurrence of impact friction contacts of reagent particles and excluding aggregation of the nanosized particles of the target reaction product. Derivation of kinetic equations for mechanochemical synthesis of nanoscale particles by the final product dilution method in the systems of exchange reactions is submitted. On the basis of obtained equations the necessary times of mechanical activation for complete course of mechanochemical reactions are designed. Kinetics of solid phase mechanosynthesis of nano TlCl by dilution of initial (2NaCl+$Tl_2SO_4$) mixture with the exchange reaction product (diluent,$zNa_2SO_4$, z=z*=11.25) was studied experimentally. Some peculiar features of the reaction mechanism were found. Parameters of the kinetic curve of nano TlCl obtained experimentally were compared with those for the model reaction KBr+TlCl+zKCl=(z+1) KCl+TlBr (z=z1*=13.5), and for the first time the value of mass transfer coefficient in a mechanochemical reactor with mobile milling balls was evaluated. Dynamics of the size change was followed for nanoparticle reaction product as a function of mechanical activation time.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.405-406
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• 2005

A theoretical investigation of the solid-phase mechanochemical synthesis of nano-sized target product on the basis of dilution of the initial powdered reagent mixture by another product of an exchange reaction is presented. On the basis of the proposed 3-mode particle size distribution in mechanically activated mixture, optimal molar ratios of the components in mixture are calculated, providing the occurrence of impact-friction contacts of reagent particles and excluding aggregation of the nanosized particles of the target reaction product. Derivation of kinetic equations for mechanochemical synthesis of nanoscale particles by the final product dilution method in the systems of exchange reactions is submitted. On the basis of obtained equations the necessary times of mechanical activation for complete course of mechanochemical reactions are designed. Kinetics of solid phase mechanosynthesis of nano-TlCl by dilution of initial (2NaCl + $Tl_2SO_4$) mixture with the exchange reaction product (diluent, $zNa_2SO_4$, $z=z^*=11.25$) was studied experimentally. Some peculiar features of the reaction mechanism were found. Parameters of the kinetic curve of nano-TlCl obtained experimentally were compared with those for the model reaction KBr + TlCl + zKCl = (z + 1) KCl + TlBr ($z=z_l^*=13.5$), and for the first time the value of mass transfer coefficient in a mechanochemical reactor with mobile milling balls was evaluated. Dynamics of the size change was followed for nanoparticle reaction product as a function of mechanical activation time.

• 응용통계연구
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• 제17권3호
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• pp.489-498
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• 2004

이 논문에서는 일반화가중선형모형이라는 새로운 형태의 선형모형을 제시한다. 일반화가중선형모형은 설명변수와 반응변수의 관계를 설명분포함수의 선형결합이 반응변수의 평균에 대한 연결분포함수를 통해 모형화 되는 형태를 가지는 것으로 가정한다. 이모형은 일반화선형 모형에서 연결함수를 선택할 때 발생할 수 있는 모수공간과 선형 예측값의 공간이 일치하지 않을 수 있다는 문제가 발생하지 않고 모수에 대한 해석이 용이하다는 장점이 있다. 이 논문에서는 설명분포함수와 연결분포함수를 선택하는데 있어 발생할 수 있는 문제와 해결책에 대해 알아본다. 또한 모형에 포함되어 있는 모수를 추정하는데 고려해야 할 주의 사항과 이 사항들을 고려한 최대가능도추정법과 재표집 방법을 이용한 구간추정과 가설검정에 대해 알아본다.

• 대한수학회논문집
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• 제14권2호
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• pp.405-423
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• 1999

We consider a statistical multiplexer model with finite buffer capacity and finite number of independent identical 3-state bursty voice sources. The burstiness of the sources is modeled by describing both two different active periods (at the rate of one packet perslot) and the passive periods during which no packets are generated. Assuming a mixture of two geometric distributions for active period and a geometric distribution for passive period and geometric distribution for passive period, we derive the recursive algorithm for the probability mass function of the buffer contents (in packets). We also obtain loss probability and the distribution of packet delay. Numerical results show that the system performance deteriorates considerably as the variance of the active period increases. Also, we see that the loss probability of 2-state Markov models is less than that of 3-state Markov models.

• 한국방재안전학회논문집
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• 제13권4호
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• pp.25-36
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• 2020

기후변화로 인해 다양한 자연재해의 발생빈도 및 강도가 증가하고 있으며, 이를 대비하기 위하여 행정안전부에서 가뭄과 대설까지 포함한 자연재해저감 종합계획을 발표하였다. 강설량은 기온과 지형적 요인의 영향을 크게 받는다. 산악지형이 많은 강원도는 강설량이 많아 큰 적설량이 관측되지만, 겨울철 평균 온도가 상대적으로 높은 남부지방은 적설량이 작다. 무강설과 결측으로 인해 관측값에 0이 포함된 경우가 존재한다. 자료에 포함된 0은 통계적으로 민감하게 작용하며, 최적 확률분포 선정과 매개변수 추정이 어려워지는 문제점이 발생한다. 본 연구에서는 창원, 통영, 진주 관측소의 최심신적설에 대해 혼합분포를 적용하여 0을 구분하였고, 0에 근사한 값을 나누는 기준인 임계값을 매개변수 𝛿로 가정함으로써 무적설 기준을 자동으로 모형에서 추정하도록 하였다. Bayesian기법 활용하여 혼합분포모형의 매개변수를 추정하였고, 산정된 빈도별 확률적설심의 불확실성을 정량화하였다. 대관령 지점과 비교한 결과, 본 연구의 혼합분포모형은 적설량이 적은 지점에 대해 적용성이 우수한 것으로 평가되었다.

• Communications for Statistical Applications and Methods
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• 제10권2호
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• pp.607-617
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• 2003

This paper offers a practical comparison of efficiency between local likelihood approach and conventional kernel approach in density estimation. The local likelihood estimation procedure maximizes a kernel smoothed log-likelihood function with respect to a polynomial approximation of the log likelihood function. We use two types of data driven bandwidths for each method and compare the mean integrated squares for several densities. Numerical results reveal that local log-linear approach with simple plug-in bandwidth shows better performance comparing to the standard kernel approach in heavy tailed distribution. For normal mixture density cases, standard kernel estimator with the bandwidth in Sheather and Jones(1991) dominates the others in moderately large sample size.

• Bulletin of the Korean Chemical Society
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• 제21권11호
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• pp.1133-1137
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• 2000

Gibbs ensemble Monte Carlo simulations were performed to calculate the vapor- liquid coexistence properties for the binary mixtures $CO_2/C_3H8$, $CO_2/CH_3OCH_3$, and $CO_2/CH_3COCH_3.$ For all the molecules the potential between sites in different molecules was simply calculated by the Lennard-Jones potential. Density of the mixture, composition of the mixture, the pressure-composition diagram, the chemical potential of component, and the radial distribution function were calculated at vapor- liquid equilibrium. The composition and the density of both vapor and liquid from simulation agreed considerably well with the experimental values over a wide range of pressures. The radial distribution functions in the liquid mixtures showed that $CO_2$ molecules tended to form cluster with each other and $C_3H8$ molecules also aggregated each other due to the weak interaction between $CO_3$ and $C_3H8$ molecule. However the interaction potentials between the same components were similar to those between the different components in the liquid mixtures $CO_2/CH_3OCH_3$ and $CO_2/CH_3COCH_3$.

• Water Engineering Research
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• 제1권1호
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• pp.49-61
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• 2000

Magnitude-frequency relationships are used in the design of dams, highway bridges, culverts, water supply systems, and flood control structures. In this paper, possible techniques for analyzing flood frequency at a site are presented. A currently used approach to flood frequency analysis is based on the concept of parametric statistical inference. In this analysis, the assumption is make that the distribution function describing flood data in known. However, such an assumption is not always justified. Even though many people have shown that the nonparametric method provides a better fit to the data than the parometric method and gives more reliable flood estimates. the noparpmetric method implies a small probability in extrapolation beyond the highest observed data in the sample. Therefore, a remedy is presented in this paper by introducing an estimator which mixes parametric and nonparametric density estimate.

• 국제초고층학회논문집
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• 제3권3호
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• pp.191-198
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• 2014

The tall building and super tall building has been a common building type in China, with multiple functions and complex geometry. Composite construction is broadly used in tall building structures and constitutes the mixed structure together with concrete and steel constructions. The mixture of the constructions is purposely designed for specific area based on the analysis results to achieve the best cost-effectiveness. New types of composite construction are conceived of by engineers for columns and walls. Material distribution is more flexible and innovative in the structural level and member level. However the reliability of computer model analysis should be verified carefully. Further researches in the design and build of composite construction are necessary to ensure the success of its application. Composite or Mixture Index is suggested to be used as a performance benchmark.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 추계학술대회 논문집
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• pp.165-168
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• 1999

The electron transport coefficients in mixture gas includes SF/sub 6/ is analysed in range of E/N values from 60∼800(Td) by the Boltzmann method that using a set of electron collision crass sections determined by the researchers. Swarm parameters in the Boltzmann method simulation such as electron drift velocity, ionization and electron attachment coefficients is in nearly agreement with the respective experimental and theoretical for a range of E/N.