• Communications for Statistical Applications and Methods
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• v.2 no.2
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• pp.296-302
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• 1995

When heteroscedasticity occurs in random effects linear model, the error variance may depend on the values of one or more of the explanatory variables or on other relevant quantities such as time or spatial ordering. In this paper we derive a score test as a diagnostic tool for detecting non-constant error variance in random effefts linear model based on the model expansion on error variance. This score test is compared to loglikelihood ratio test.

• YAKHAK HOEJI
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• v.20 no.1
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• pp.41-43
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• 1976

The dissociation constant of phenol red indicator in mixed solvents was studied. Methanol and ethanol were employed as solvents and studied the changes of pK values of indicator according to the kind and concentration of organic solvent which is mixed into water solution. The effect of methanol solvent on pK is negligible at 40%, 60% and 80% mixing. While in the case of ethanol, the effect of above 40% mixing is not negligible.

• Journal of the Korean Society of Tobacco Science
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• v.3 no.1
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• pp.30-40
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• 1981

The moisture sorption and desorption isotherms of various tobaccos were obtained over a relative humidity range from 0 to 90% at $20^{\circ}C$ and $30^{\circ}C$. The hysteresis effect, constant and rate of moisture sorption and desorption, monomolecular-layer moisture content, and specific surface area were analyzed from the obtained data. The moisture sorption and desorption isotherms showed a different characteristics for different tobacco varieties. At a lower humidity range below 50% RH, Burley tobacco had higher moisture sorption and desorption figures than Hicks and Basma, while, at a higher humidity range above 50% RH, Hicks had higher values than the others. The hysteresis effect of tobacco were greater in an intermediate humidity range (40-70% RN), and Basma showed a greater effect than the others. The sorption and desorption constant (K) increased with temperature, but decreased with RH, and Burley tobacco had larger K values, while Hicks had smaller K values than others. The sorption and desorption rate of Burley tobacco were greater than the other tobaccos. The monomolecular-layer moisture was 27.8 and 51.4mg/g, and the specific surface was 101 and $186m^2/g$, for Basma and Burley, respectively.

• Journal of the Korean Chemical Society
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• v.3 no.1
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• pp.23-27
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• 1954

The relation between the height of ascending solvents and its velocity were studied with strips of Toyo No. 50 filter paper. The filter paper strip of 3cm width and cat 30 cm length is hooked down or fixed between two sheets of glass plates inside a cylinder containing the solvent, in which the lower end of the strip is dipped. As the solvents, acetone, hydrochloric acid, water or mixtures of these are used. For short time intervals, Ostwald's folmula $h = Kt^n$ was found to be most suitable to express the relation between the height of the solvent front, h, and time, t. For longer time intervals, results will be discussed in the next paper. The mean values of the constant m in the above formula for pure acetone and pure water were 0.44 and 0.485, respectively, and that of K were 0.05 and 2.4, respectively. The time interval whose the above formula applies, for each solvent was 2 hours for the former, and a half hour for the later, respectively. The movement of solutes, such as $Cu^{++}$ and $Fe^{++}$ showed that the Rf values of solutes become constant values after a long periods; e.g., ca. 6 hours with 10N-HCl-Acetone (1 : 9) solvent.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.135-135
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• 2022

In this study, we evaluated uncertainties in baseflow separation filter methods focusing on changes in recession constant (𝛼) values, which include Lynie & Holick (LH) algorithm, Chapman algorithm, Eckhardt filter, and EWMA filter. Here, we analyzed daily streamflow data at 14 stations in the Urmia Lake basin, Iran, from 2015 to 2019. The 𝛼 values were computed using three different approaches from calculating the slope of a recession curve by averaging the flow over all seasons, a correlation method, and a mean value of the ratio of Q_t+1 to Q_t. In addition to the 𝛼 values, the BFImax (maximum value of the baseflow index (BFI)) was determined for the Eckhardt filter through the backward filter method. As results, it indicates that the estimated baseflow is dependent upon the selection of filter methods, their parameters, and catchment characteristics at different stations. In particular, the EWMA filter showed the least changes in estimating the baseflow value by changing the 𝛼 value, and the Eckhardt filter and LH algorithm showed the highest sensitivity to this parameter at different stations.

• Progress in Superconductivity and Cryogenics
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• v.26 no.1
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• pp.14-19
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• 2024

In this study, we explore the anisotropy of electron-phonon coupling (EPC) constant in epitaxially grown MgB₂ films on c-axis oriented Al₂O₃, examining its correlation with the critical temperature (T_c) and local structural disorder assessed through polarized Raman scattering. Analysis of the polarized Raman spectra reveals angle-dependent variations in the intensity of the phonon spectra. The Raman active mode originating from the boron plane, along with two additional phonon modes from the phonon density of states (PDOS) induced by lattice distortion, was distinctly observed. Persistent impurity scattering, likely attributed to oxygen diffusion, was noted at consistent frequencies across all measurement angles. The EPC values derived from the primary Raman active phonon do not significantly vary with changing observation angles, followed by that the T_c values calculated using the Allen and Dynes formula remain relatively constant across all polarization angles. Although the E_2g phonon mode plays a crucial role in the EPC mechanism, the determination of T_c values in MgB₂ involves not only electron-E_2g coupling but also contributions from other phonon modes.

• Bulletin of the Korean Chemical Society
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• v.6 no.1
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• pp.37-40
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• 1985

The electrical conductance and UV absorbance of 4,N-dimethyl Pridinium Iodide (NDMPI) were measured in the ethanol volume percentage, 95, 90, 80 and 60 of an ethanol-water mixture at 15, 25, 35 and $45^{\circ}C$. Ionic association constants(K) of NDMPI were evaluated in accordance with a combined method of conductance UV absorbance. The ion size parameter (${\gamma}_{\pm}$) and dipole momemt (${\mu}_{A+D-}$) of NDMPI were obtained from the values of K and dielectric constant. The ${\mu}_{A+D-}$- values were in good agreement with the values of transition moment(${\mu}_{mn}$) which is calculated form the UV peak values. The large negative values of the electrical enthalpy (${\Delta}H_{el}^{\circ}$) and entropy (${\Delta}H_{el}^{\circ}$ ) have proved that NDMPI had a positive hydration. The positive values of entropy (${\Delta}S^{\circ}$) means the formation of NDMPI ion goes with dehydration.

• Environmental Engineering Research
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• v.22 no.4
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• pp.339-346
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• 2017

The objective of this study is the evaluation of the performance of a large-scale respirometer (LSR) of 17.7 L in the determination of the methane generation rate constant (k) values. To achieve this objective, a comparison between anaerobic (GB21) and LSR tests was conducted. The data were modeled using a linear function, and the resulting correlation coefficient ($R^2$) of the linear regression is 0.91. This result shows that despite the aerobic conditions, the biodegradability values that were obtained from the LSR test produced results that are similar to those from the GB21 test. In this respect, the LSR test can be an indicator of the anaerobic biodegradability for landfill waste. In addition, the results show the high repeatability of the tests with an average coefficient of variance (CV) that is lower than 10%; furthermore, the CV for the LSR is lower than that of the GB21, which indicates that the LSR-test method could provide a better representation of waste samples. Therefore, the LSR method allows for both the prediction of the long-term biodegradation potential in a shorter length of time and the reduction of the sampling errors that are caused by the heterogeneity of waste samples. The k values are $0.156y^{-1}$ and $0.127y^{-1}$ for the cumulative biogas production (GB21) and the cumulative oxygen uptake for the LSR, respectively.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.4
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• pp.127-133
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• 2013

This paper compare the performance of CCA (Compact Constellation Algorithm) adaptive equalization algorithm by effect of the compact slice weighting value for minimization of the intersymbol interference in the communication channel. The CCA combines the conventional DDA and RCA algorithm, it uses the constant modulus of the transmission signal and the considering the output of decision device by the power of compact slice weighting value in order to improving the initial convergence characteristics and the equalization noise by misadjustment in the steady state. In this process, it is confirmed by computer simulation that the compact slice weight affects the performance of CCA adaptive equalization algorithm. The performance index includes the output signal constellation, the residual isi and maximum distortion and MSE that is for the convergence characteristics, the SER according to the signal and noise power ratio at the channel is used. As a result of computer, it shows that the large weighting value gives more good in every performance index. But in SER performance, it is known that the small values gives more good in low SNR and the large values gives more good in high SNR.

• Journal of KIISE
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• v.43 no.1
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• pp.34-39
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• 2016

JavaScript is widely used in web pages with HTML. Many JavaScript engines adopt Just-in-time compilers to accelerate the execution of JavaScript programs. Recently, many newly introduced devices are adopting 64-bit CPUs instead of 32-bit and Just-in-time compilers for 64-bit CPU are slowly being introduced in JavaScript engines. However, there are many inefficiencies in the currently available Just-in-time compilers for 64-bit devices. Especially, the size of code is significantly increased compared to 32-bit devices, mainly due to 64-bit wide addresses in 64-bit devices. In this paper, we are going to address the inefficiencies introduced by 64-bit wide addresses and values in the Just-in-time compiler for the V8 JavaScript engine and propose more efficient ways of generating constant values and addresses to reduce the size of code. We implemented the proposed optimization in the V8 JavaScript engine and measured the size of code as well as performance improvements with Octane and SunSpider benchmarks. We observed a 3.6% performance gain and 0.7% code size reduction in Octane and a 0.32% performance gain and 2.8% code size reduction in SunSpider.