• 응용통계연구
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• 제30권5호
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• pp.793-808
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• 2017

본 논문에서는 초고차원 자료의 다항분류를 위한 변수선별 방법에 대해 비교 연구를 진행하였다. 다항분류를 위한 변수선별 방법에는 일대일 혹은 일대다 비교를 통해 이항분류를 위한 방법을 확장시켜 적용하는 방법과 다항 반응 변수에 직접 적용할 수 있는 방법이 있다. 다항분류를 위한 변수선별 성능을 확인하기 위하여 여러가지 상황-설명변수의 꼬리가 두꺼운 경우, 신호변수와 잡음변수가 서로 연관된 경우, 결합분포상으로 연관되어 있지만 주변분포 상으로는 연관되어 있지 않은 경우, 다범주 반응변수의 분포가 불균형인 경우-을 가정하고 모의실험을 진행하였고, 실제 자료에도 적용해 보았다. 그 결과, 모형 가정을 필요로 하지 않는 방법들이 안정적인 성능을 보이는 것을 확인하였다.

• Korean Chemical Engineering Research
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• 제56권5호
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• pp.663-678
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• 2018

Refractive index and speeds of sound for the binary mixture of isomer of butanol (1) + cyclohexane, benzene and toluene (2) were measured at 308.15 K. The measured data were used to calculate deviation in refractive index ${\Delta}n$, ultrasonic speed ${\Delta}u$, isentropic compressibility $K_s^E$, available volume $V_a$, excess intermolecular free length $L_f$ and molecular association $M_A$. All the derived properties were correlated with polynomial equation. Ultrasonic speed data were predicted using various empirical correlations like Nomoto, van Dael, impedance dependence and theoretically with Schaaff's collision factor theory (CFT). Jacobson free length theory (FLT) was used to calculate $L_f$. The measured refractive index was also correlated with various mixing rules. The deviation in refractive index Δn and ultrasonic speed ${\Delta}u$ was used to determine the intermolecular interactions.

• Korean Chemical Engineering Research
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• 제58권2호
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• pp.257-265
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• 2020

Densities (ρ) for binary mixtures of ethanol (1) + diisopropyl ether (DIPE) or cyclohexane or alkane (C₆-C₉) (2) were measured at 298.15 K, 308.15 K and 318.15 K. The excess molar volume (V^E_m) of binary mixtures was calculated using ρ data and correlated with Redlich-Kister polynomial equation. The V^E_m values for binary mixtures of ethanol (1) + cyclohexane or n-alkane (C₆-C₉) (2) were positive, whereas for ethanol (1) + DIPE (2) these were negative. The magnitude of V^E_m values follows the order: cyclohexane > n-nonane > n-octane > n-heptane > n-hexane > DIPE. The V^E_m values have been interpreted qualitatively and also quantitatively in terms of Flory-Treszczanowicz-Benson (FTB) model and Prigogine-Flory-Patterson (PFP) theory. The values V^E_m predicted using FTB model agree well with experimental V^E_m values at all mole fractions. But the PFP theory describes well V^E_m data in ethanol-rich region (x₁ > 0.5) for all binary mixtures and is able to predict the sign of V^E_m vs x₁ curve for ethanol-lean region (x₁ < 0.5) except for ethanol (1) + nonane (2) mixtures.

• 에너지공학
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• 제2권3호
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• pp.308-314
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• 1993

15mbar 정합하에서 n.dodecane-1.decanol-1.dodecanol 혼합물의 삼성분계 및 각 이성분계의 기액평형 데이타와 비점을 측정하였다. 측정된 기액평형 데이타는 g$^{E}$ 모델식 인 Margules, van Laar, Wilson, NRTL, UNIQA 식에 의해 상관관계를 알아보았다. 이성분계 데이타는 Redlich-Kister의 적분법에 의해 열역학적으로 검토하였으며, 삼성분계 데이터 역시 McDermott-Ellis에 의한 two-point consistency test에 의해 질적으로 검토되었다. 이성분계의 기액평형 데이타 중에 n.dodecane-1.decanol계 만이 공비점을 보였다.

• 대한화학회지
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• 제56권4호
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• pp.424-430
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• 2012

Densities, viscosities, refractive indices and speed of sounds of the binary mixtures of Acetophenone with Ethylchloroacetate were measured over the entire mole fractions at (303.15, 313.15 and 323.15) K. From these experimental results, excess molar volume $V^E$, viscosity deviation ${\Delta}{\eta}$, refractive index deviation ${\Delta}n_D$, deviations in speed of sound ${\Delta}u$, deviations in isentropic compressibility ${\Delta}k_s$ and excess intermolecular free length ${\Delta}L_f$ were calculated. The viscosity data have been correlated with the equations of Grunberg and Nissan, Hind et al., Tamura and Kurata, Katti and Chaudri, Sedgwick, Krishnan-Laddha and McAllister. The thermo physical properties under study were fit to the Jouyban-Acree model. The excess values were correlated using Redlich-Kister polynomial equation to obtain their coefficients and standard deviations. It was found that in all cases, the data obtained fitted with the values correlated by the corresponding models very well. The results are interpreted in terms of molecular interactions occurring in the solution.

• 공업화학
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• 제21권3호
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• pp.295-300
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• 2010

1-propanol과 bromochloromethane 혼합물은 공비점의 형성이나 큰 휘발성 차이 때문에 실제 증류탑이나 흡수탑 등의 단위 공정에서 효율적이고 경제적인 운전이 쉽지 않다. 이처럼 비이상성이 큰 혼합물을 효과적으로 다루기 위해서는 혼합물에 대한 기-액 평형 등의 열역학적인 정보가 필수적이다. 본 연구에서는 재순환 기-액 평형장치를 이용하여 일정 압력 하에서 30 kPa에서 70 kPa까지 1-propanol과 bromochloromethane 혼합물의 기-액 평형을 측정하였으며 얻어진 실험 데이터를 UNIQUAC과 NRTL 모델식을 이용하여 상관하였고 과잉 Gibbs 에너지와 활동도 계수를 추산하였다. 또한 Gibbs/Duhem식에 근거한 열역학적 건전성 테스트를 수행하였고 진동 밀도계를 사용하여 이성분계의 과잉 몰부피를 측정하였으며 그 결과를 Redlich-Kister다항식으로 상관하였다.

• 설비공학논문집
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• 제12권11호
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• pp.1031-1037
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• 2000

Isothermal vapor-liquid equilibrium(VLE) data have been obtained for the systems of propane(R290)+1,1,1,2-tetrafluoroethane(R134a) and 1,1,1,2-tetrafluoroethane(R134a)+isobutane(R60A) in the temperature range of 253.15 to 323.15K. Experiments were performed in a circulation type apparatus by injecting vapor through liquid pool using a magnetic pump. Both systems form azeotropes in the temperature range of this study. The experimental results were estimated with the Peng-Robinson equation of state. When the temperature-dependent binary interaction parameter was used in the Peng-Robinson equation of state, the absolute average deviation of the measured bubble point pressures from the values correlated by the Peng-Robinson equation was 0.65% and 0.78% for R290+R134a and R134a+600a, respectively. Azeotropic compositions for both systems were presented.

• 한국지반공학회지:지반
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• 제9권3호
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• pp.61-66
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• 1993

본 논문에서는 암반 분류를 위해 물리탐사 결과나 그동안 축적된 시공경험 등의 정성적 자료의 사용을 고려하였다. 터널 설계를 위한 요소(parameter)들이 공간적 상관관계를 갖기 때문에 지구 통계학(Geostatistics)을 이용하였으며, 특히, 비모수적 (non-parametric)방법 중의 하나인 지시 크리깅(indicator kriging) 기법을 사용했다. 최적 분류를 위한 선택 기준으로는 오차에 대응하는 비용(the cost of errors)을 사용했으며, 암반분류는 이분적 분류에 한정하였다. 앞으로, 정량적 데이타가 절대적으로 부족한 터널공사등에서 비교적 많은 양이 존재하는 정성적 데이타의 이용은 절실하며, 이러한 점에서 본 연구가 가지는 의미는 크다.

• Bulletin of the Korean Chemical Society
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• 제33권5호
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• pp.1686-1692
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• 2012

Densities (${\rho}$), Viscosities (${\eta}$) and ultrasonic speeds (u) of pure acetophenone (AP), propiophenone (PP), $p$-methyl acetophenone ($p$-MeAP), $p$-chloroacetophenone ($p$-ClAP) and those of their binary mixtures with $N$-ethyl aniline ($N$-EA) as a common component, were measured at 303.15 K over the entire composition range. These experimental data were used to calculate the excess volume $V^E$, deviation in ultrasonic speeds ${\Delta}u$, isentropic compressibility $K_s$, intermolecular free length $L_f$, acoustic impedance Z, deviations in isentropic compressibility ${\Delta}K_s$, deviation in viscosity ${\Delta}{\eta}$ and excess Gibbs free energy of activation of viscous flow ($G^{*E}$) at all mole fractions of $N$-ethyl aniline. These parameters, especially excess functions, are found to be quite sensitive towards the intermolecular interactions between component molecules. Theoretical values of viscosity of the binary mixtures were calculated using different empirical relations and theories. The relative merits of these relations and theories were discussed. The experimental results were correlated by using the polynomial proposed by Redlich-Kister equation.

• 대한기계학회논문집B
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• 제24권9호
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• pp.1239-1246
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• 2000

The objective of this work is to measure space and time resolved wall heat fluxes during nucleate pool boiling of R113/R11 mixtures using a microscale heater array in conjunction with a high speed CCD. The microscale heater array is constructed using VLSI techniques, and consists of 96 serpentine platinum resistance heaters on a transparent quartz substrate. Electronic feedback circuits are used to keep the temperature of each heater at a specified temperature and the variation in heating power required to keep the temperature constant is measured. Heat flux data around an isolated bubble are obtained with triggered CCD images. CCD images are obtained at a rate of 1000frames/second. The heat transfer variation vs. time on the heaters directly around the nucleation site is plotted and correlated with images of the bubble obtainedby using the high speed CCD. For both of the mixture(R11/R113) and pure system(pure R11, pure R113), the wall heat fluxes are presented and compared to find out the qualitative difference between pure and binary mixture nucleate boiling.