• The Korean Journal of Food And Nutrition
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• v.9 no.1
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• pp.29-36
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• 1996

Naengmyon is a Korean buckwheat noodle with chilld broth, and the juice of dongchimi, a Korean radish pickle fermented with wild lactic acid bacteria, has been used as the broth for naengmyon traditionally. The purpose of this study was to demonstrate the inhibitory effect of dongchimi-juice against coliform bacteria in model system of naengmyon-broth. Dongchimi-juice was made from radish juice by the cultivation of lactic acid bacteria which had been isolated from kimchi. Three types of naengmyon-broth, beef-broth type, dongchimi-juice type and the mixed type, were made as model systems, and then the changes in viable cell counts of seven coliform bacteria, Klebsiella planticola Bo2, X. terrigena CO8, K. pneumoniae DOI, K. ozaenae DO4, Enterobacter sp. AO2, Enterobacter sp. CO7, Citrobacter sp. BO7 and Escherichia sp. DO3, which had been added to each type of naengmyon-broth in advance, were investigated during storage at 3$0^{\circ}C$ All coliforms grew rapidly in naengmyon-broth of beef-broth type, while none grew in dongchimi-juice type or in the mixed type. All coliforms died out far more rapidly in dongchimi-juice type than in mixed type. The decreasing slopes of Citrobacter sp. Bo7, K. planticola BO2, X. terrigena CO8 and K. ozaenae DO4 were more steep than those of the rest. It was thought that the preparation method of Korean traditional naengmyon such as dongchimi-naengmyon or Pyongyang style-naengmyon, which uses oxy dongchimi-) juice or the mixture of dongchimi-juice and beef-broth, would be very effective for preventing the growth of coliform bacteria from naengmyon.

• Fire Science and Engineering
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• v.13 no.1
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• pp.11-19
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• 1999

The flash point is generally used as a hazardous index of fire and explosion of a flammable liquid. A classification of the flash points is important for the safe handling of flammable liquids such as solvent mixtures. The flash points of pure substances and solvent mixtures can be c calculated with the appropriate use of the fundamental laws of Raoult, Dalton, Le Chatelier and a activity coefficient models. In this study, experimentally determined lower and upper flash points w were compared with the calculated values by using Raoult's law and van Laar equation. The flash points of pure substances were in agreement with the calculated values by vapor pressure and e explosive limits. Also, the lower flash points of M.E.K(methylethylketone)-toluene system were i in agreement with the predicted values by Raoult’s law, and the upper flash points were in a agreement with the predicted values by van Laar equation. By means of this methodology, it is possible to evaluate reliability of expermental data of the flash points of the flammable mixtures.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.11
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• pp.3253-3259
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• 2009

In this study, a computer simulation has been performed for the refrigeration cycle using mixed refrigerants in order to decrease the process stream temperature to $-20^{\circ}C$. Refrigerant supply temperature was assumed to be $-30^{\circ}C$ considering the temperature difference as $10^{\circ}C$ with process stream. Peng-Robinson equation of state model was selected for the computer simulation. A new alpha function proposed by Twu et al was used for an accurate prediction of pure component vapor pressure experimental data. One fluid mixing rules were used for the estimation of mixture vapor-liquid equilibria calculations. A commercial process simulator, PRO/II with PROVISION was utilized for the simulation of the overall refrigeration process. In order to minimize the compressor power consumption, we have optimized the two-stage compression system by varying the first stage compressor outlet pressure. Finally, we could obtain the minimum total power 755.7kW at the first stage compressor outlet pressure, 6 bar.

• Applied Chemistry for Engineering
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• v.9 no.4
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• pp.469-474
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• 1998

Poly (vinyl alcohol) (PVA) membranes crosslinked with poly (styrene-co-maleic anhydride) (PSMAn) have been prepared by the solution method. To investigate the separation behavior of the crosslinked PVA/PSMAn membranes in the pervaporation process, the selective sorption experiment and swelling measurements of the membranes in ethanol-water mixtures of 30~90 wt % ethanol contents were conducted with equipment that was able to measure the concentration and amount of the liquid absorbed in the membranes. The membranes prepared in this study exhibited good selectivity toward water component in sorption and permeation. Also, in the feed containing ethanol more than 50 wt %, the permeation selectivity of the membrane showed better correlation with the sorption selectivity than that with the swelling ratio changing toward the crosslinking content. This behavior was consistence with a solution-diffusion model correlating permeation and sorption selectivity, and led to the conclusion that the permeation selectivity was determined by sorption step rather than by diffusion step in the membrane.

• Journal of the Korea Institute of Building Construction
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• v.11 no.4
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• pp.371-378
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• 2011

Concrete is affected by various deterioration factors, such as $CO_2$ and chloride ions from the sea, which cause carbonation and salt attack on concrete. These deterioration phenomena cause steel corrosion in RC structures. Although a great deal of research has been carried out in this area thus far, it is difficult to know the point at which corrosion will occur to a reinforced bar. As the diffusion of deterioration factors depends on the water content in concrete, it is imperative to assess the condition of absorbed water content. A mass measuring method was applied to calculate the absorbed water diffusion coefficient, as well as non-linear finite element method(FEM) analysis. As a result, it was found that W/C and unit water content in concrete mixture affect the diffusion coefficient decision.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.2C
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• pp.181-187
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• 2012

Millimeter wave (MMW) readily penetrates fabrics, thus it can be used to detect objects concealed under clothing. A passive MMW imaging system can operate as a stand-off type sensor that scans people in both indoors and outdoors. However, because of the diffraction limit and low signal level, the imaging system often suffers from low image quality. Therefore, suitable statistical analysis and computational processing would be required for automatic analysis of the images. In this paper, a real-time concealed object detection is addressed by means of the multi-level segmentation. The histogram of the image is modeled with a Gaussian mixture distribution, and hidden object areas are segmented by a multi-level scheme involving $k$-means, the expectation-maximization algorithm, and a decision rule. The complete algorithm has been implemented in C++ environments on a standard computer for a real-time process. Experimental and simulation results confirm that the implemented system can achieve the real-time detection of concealed objects.

• The Korea Journal of Herbology
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• v.23 no.1
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• pp.53-61
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• 2008

Objectives : The aim of this study was to investigative the effects of Gagambojungikgi-tang (GBT), a Korean herbal medicine, on the immune mediators, T cell proliferation and wound healing in the recombinant Sj26 (rSj26) antigen induced atopic dermatitis(AD) model mice. Methods : GBT is the water extracts prepared from mixture of Ginseng Radix, Astragali Radix, Angelicae gigantis Radix, Atractylodes Rhizoma alba, Aurantii nobilis Pericarpium, Glycyrrhizae Radix, Artemisia iwayomogi Herba, Scutellaria Radix, Lonicera japonica Flos. This is a modified prescription of Bojungikgi-tang, which has been used for the treatment of indigestion, and immunological disease in east-asian countries. GBT was orally administered or externally applied at difference doses. The levels of immune mediators [(IgE, IgG1, prostaglandin E2 (PGE2), Th1/Th2 cytokines], T cell proliferation, and wound healing in the rSj26 or chemical antigen induced AD model BALB/c were investigated. Results : GBT dose-dependently suppressed the release of TNF-${\alpha}$, IL-$1{\beta}$ (Th1 cytokines), IL-4, IL-10 (Th2 cytokines), PGE2 (inflammatory mediators) and T cell proliferation. But GBT increased the production of IFN-${\gamma}$ (Th1 cytokine). Furthermore, A wound healing effect of GBT was similar to external application of dexamethasone. Conclusions : These results suggest that GBT suppresses the inflammatory mediators and regulates the Thl/Th2 cytokines, and promotes the wound healing. Therefore, these properties may contribute to the strong anti-AD effect of GBT.

• The Journal of the Acoustical Society of Korea
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• v.24 no.3
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• pp.150-159
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• 2005

This paper addresses a voice personality transformation algorithm which makes one person's voices sound as if another person's voices. In the proposed method, one person's voices are represented by LPC cepstrum, pitch period and speaking rate, the appropriate transformation rules for each Parameter are constructed. The Gaussian Mixture Model (GMM) is used to model one speaker's LPC cepstrums and conditional probability is used to model the relationship between two speaker's LPC cepstrums. To obtain the parameters representing each probabilistic model. a Maximum Likelihood (ML) estimation method is employed. The transformed LPC cepstrums are obtained by using a Minimum Mean Square Error (MMSE) criterion. Pitch period and speaking rate are used as the parameters for prosody transformation, which is implemented by using the ratio of the average values. The proposed method reveals the superior performance to the previous VQ-based method in subjective measures including average cepstrum distance reduction ratio and likelihood increasing ratio. In subjective test. we obtained almost the same correct identification ratio as the previous method and we also confirmed that high qualify transformed speech is obtained, which is due to the smoothly evolving spectral contours over time.

• Membrane Journal
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• v.9 no.1
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• pp.25-35
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• 1999

The sorption and permeation experiments with $O_2$ and $N_2$ were performed with poly sulfone hollow-fiber membrane to obtain oxygen-enriched air. Sorption of $O_2$ on poly sulfone membrane was 1.5'||'&'||'not;2.0 times higher than that of N2. Sorption of oxygen and nitrogen in poly sulfone membrane was described satisfactorily with "dual-mode sorption model". In the low pressure range below 3kgr!cm', about 85% of total sorption was Langmuir-type sorption and only 15% was Henry-type sorption. In the higher pressure above 3kgf/${cm}^2$, Langmuir sorption sites became almost saturated and reached asymptote, and the increase in total sorption with pressurizing might be due to the Henry~type sorption. The ideal separation factor ( P $O_2$/ P $N_2$) was in the range of 2~4, while the actual separation factor for the mixture was reduced to the value of 1.7~2.2.2.2.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1404-1414
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• 2008

In the mechanistic-empirical trackbed design of railways, the resilient modulus is the key input parameter. This study focused on the resilient modulus prediction model, which is the functions of mean effective principal stress and axial strain, for three types of railroad trackbed materials such as crushed stone, weathered soil, and crushed-rock soil mixture. The model is composed with the maximum Young's modulus and nonlinear values for higher strain in parallel with dynamic shear modulus. The maximum values is modeled by model parameters, $A_E$ and the power of mean effective principal stress, $n_E$. The nonlinear portion is represented by modified hyperbolic model, with the model parameters of reference strain, ${\varepsilon}_r$ and curvature coefficient, a. To assess the performance of the prediction models proposed herein, the elastic response of a test trackbed near PyeongTaek, Korea was evaluated using a 3-D nonlinear elastic computer program (GEOTRACK) and compared with measured elastic vertical displacement during the passages of freight and passenger trains. The material types of sub-ballasts are crushed stone and weathered granite soil, respectively. The calculated vertical displacements within the sub-ballasts are within the order of 0.6mm, and agree well with measured values with the reasonable margin. The prediction models are thus concluded to work properly in the preliminary investigation.