• Magazine of the Korean Society of Agricultural Engineers
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• v.38 no.4
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• pp.110-124
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• 1996

This study was conducted to simulate long seres of synthetic monthly flows by multi-season first order Markov model with selection of best fitting frequency distribution, harmonic synthetic and harmonic regression models and to make a comparison of statistical parameters between observes and synthetic flows of five watersheds in Geum river system. The results obtained through this study can be summarized as follow. 1. Both gamma and two parameter lognormal distributions were found to be suitable ones for monthly flows in all watersheds by Kolmogorov-Smirnov test. 2. It was found that arithmetic mean values of synthetic monthly flows simulated by multi-season first order Markov model with gamma distribution are much closer to the results of the observed data in comparison with those of the other models in the applied watersheds. 3. The coefficients of variation, index of fluctuation for monthly flows simulated by multi-season first order Markov model with gamma distribution are appeared closer to those of the observed data in comparison with those of the other models in Geum river system. 4. Synthetic monthly flows were simulated over 100 years by multi-season first order Markov model with gamma distribution which is acknowledged as a suitable simulation modal in this study.

• Nuclear Engineering and Technology
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• v.48 no.1
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• pp.64-71
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• 2016

Void fraction is an important parameter in the oil industry. This quantity is necessary for volume rate measurement in multiphase flows. In this study, the void fraction percentage was estimated precisely, independent of the flow regime in gas-liquid two-phase flows by using ${\gamma}-ray$ attenuation and a multilayer perceptron neural network. In all previous studies that implemented a multibeam ${\gamma}-ray$ attenuation technique to determine void fraction independent of the flow regime in two-phase flows, three or more detectors were used while in this study just two NaI detectors were used. Using fewer detectors is of advantage in industrial nuclear gauges because of reduced expense and improved simplicity. In this work, an artificial neural network is also implemented to predict the void fraction percentage independent of the flow regime. To do this, a multilayer perceptron neural network is used for developing the artificial neural network model in MATLAB. The required data for training and testing the network in three different regimes (annular, stratified, and bubbly) were obtained using an experimental setup. Using the technique developed in this work, void fraction percentages were predicted with mean relative error of <1.4%.

• Journal of the Korean Institute of Intelligent Systems
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• v.14 no.3
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• pp.316-323
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• 2004

This paper deals with an $H_{\infty}$ output feedback controller design for singularly perturbed T-S fuzzy systems. It is shown that the $H_{\infty}$ norm of the singularly perturbed T-S fuzzy system is less than ${\gamma}$ for a sufficiently small ${\varepsilon}$>0 if the $H_{\infty}$ norms of both the slow and fast subsystem are less than ${\gamma}$. Using this fact, we develop a linear matrix inequality based design method which is independent of the singular perturbation parameter ${\varepsilon}$. A numerical example is provided to demonstrate the efficacy of the proposed design method.

• Journal of the Korean Society for Heat Treatment
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• v.14 no.1
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• pp.8-16
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• 2001

The effects of gas composition, pressure, temperature and time on the case thickness, hardness and nitride formation in the surface of tool steels(STD11 and STD61) have been studied by micro-pulse plasma nitriding. External compound layer and internal diffusion layer and the diffusion layer were observed in the nitrided case of tool steels. The relative amounts and kind of phases formed in the nitrided case changed with the change of nitriding conditions. Generally, only nitride phases such as ${\gamma}(Fe_4N)$, ${\varepsilon}(Fe_{2-3}N)$, or $Cr_{1.75}V_{0.25}N_2$ phases were detected in the compound layer, while nitride and carbide phases such as ${\varepsilon}-nitride(Fe_{2-3}N)$, $(Cr,Fe)_{\gamma}C_3$ or $Fe_3C$ were detected in the diffusion layer by XRD analysis. The thickness of compound layer increased with the increase of nitrogen content in the gas composition. Maximum case depth was obtained at gas pressure of 200Pa.

• Journal of the Korean Data and Information Science Society
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• v.24 no.5
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• pp.999-1011
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• 2013

In this research, we propose a document recommendation method which can find documents that are relatively important to a specific document based on citation information. The key idea is parameter tuning in the Neumann kernal which is an intermediate between a measure of importance (HITS) and of relatedness (co-citation). Our method properly selects the tuning parameter ${\gamma}$ in the Neumann kernal minimizing the prediction error in future citation. We also discuss some comutational issues needed for analysing large citation data. Finally, results of analyzing patents data from the US Patent Office are given.

• Journal of the Korean Chemical Society
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• v.20 no.3
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• pp.198-205
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• 1976

The integral Hellmann-Feynman Theorem of Parr is generalized to give a full significance to the off-diagonal form, and certain aspects of it are discussed. By use of the generalized form of the theorem, effects of configuration interaction to the crystal field theory are examined, taking perturbation energies of all order collectively into account. Thus, it is shown that there do not exist, especially when the field is strong, the radial integral which is common to all states characterized by ${\Gamma}$, S and m, and could be parametrized. If, however, one restricts the perturbing excited states only to those angularly undistorted and radially equally distorted, there results simple scaling of the crystal field parameter 10 Dq and Condon-Slater parameter $F^n$ defined within the framework of the classical crystal field theory.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.5
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• pp.1082-1086
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• 1999

Dried vegetables, white ginseng and spices, which were exposed to gamma and electron beam irradiation, were used in a detection study by measuring their starch content and viscosity change. The samples tested showed different levels of starch content(15.64~60.86%), which was not directly proportional to the viscosity of the samples. The correlation coefficients between irradiation dose and viscosity change were lower in the samples, such as cabbage, carrot, clean vegetable(chunggyungchae), garlic, mushroom, green onion, and red pepper, while some higher coefficients were found in ginger(R2=0.9271), white ginseng (R2=0.6223) and onion (R2=0.7909). Thus, dried ginger and white ginseng were selected to be used for a detection of irradiated samples using specific parameters(threshold values). Specific parameter for the nonirradiated ginger and ginseng were 13.31 and 13.93, respectively. On the other hand, gamma and electron beam irradiated samples at 2.5 kGy, the lowest dose for a commercial purpose, showed decreased values, 11.92 and 11.15 in ginger, and moreover 4.40 and 5.10 in ginseng. It is expected that a proportional decrease in a specific parameter with the absorbed doses will be a potentially useful index for detecting whether starchy foods have been irradiated or not.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.3
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• pp.63-71
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• 1990

The hydrodynamic model parameters for the submicron GaAs simulation are calculated using the Monte Carlo method. $\Gamma$, L-, and X-valleys are included in the conduction band of GaAs, and polar optic phonon, acoustic phonon, equivalent intervalley, non-equivalent intervalley, ionized impurity, and piezoelectric scattering are taken into account. The velocity-electric field strength curve obtained in this paper is in good agreement with experimental one. We present the results in tabular form so that other participants can make use of them to simulate the submicron GaAs devices by the hydrodynamic model.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.8
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• pp.1051-1056
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• 2001

Data for teat number for Landrace (L), Yorkshire (Y), crossbred of Landrace and Yorkshire (LY), and crossbred of Landrace, Yorkshire and Chinese indigenous Min Pig (LYM) were analyzed using Gibbs sampling. In Bayesian inference, flat priors and some informative priors were used to examine their influence on posterior estimates. The posterior mean estimates of heritabilities with flat priors were $0.661{\pm}0.035$ for L, $0.540{\pm}0.072$ for Y, $0.789{\pm}0.074$ for LY, and $0.577{\pm}0.058$ for LYM, and they did not differ (p>0.05) from their corresponding estimates of REML. When inverse Gamma densities for variance components were used as priors with the shape parameter of 4, the posterior estimates were still corresponding (p>0.05) to REML estimates and mean estimates using Gibbs sampling with flat priors. However, when the inverse Gamma densities with the shape parameter of 10 were utilized, some posterior estimates differed (p<0.10) from REML estimates and/or from other Gibbs mean estimates. The use of moderate degree of belief was influential to the posterior estimates, especially for Y and for LY where data sizes were small. When the data size is small, REML estimates of variance components have unknown distributions. On the other hand, Bayesian approach gives exact posterior densities of variance components. However, when the data size is small and prior knowledge is lacked, researchers should be careful with even moderate priors.

• Nuclear Engineering and Technology
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• v.6 no.2
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• pp.89-96
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• 1974

The cross-section ratios of the nuclear isomeric pairs $^{80}$ B $r^{m, g}$, sup 81/S $e^{m, g}$, $^{104}$ R $h^{m, g}$, $^{116}$ I $n^{m, g}$ and $^{134}$ C $s^{m, g}$ through the radiative thermal neutron capture process have been studied. The experimental values of these ratios obtained by the activation method have been compared with the calculated ones deduced from the modified Huizenga-Vandenbosch method. Agreement between these values within 30% could be attained by controlling the spin cut-off parameter and gamma-ray multiplicity.