• Journal of Korean Society of Coastal and Ocean Engineers
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• v.32 no.5
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• pp.296-306
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• 2020

It has been reported that the wave heights measured by Wave and Tide gauges (WTG) have been underestimated, and thus it is important to improve its measuring accuracy for enhancing estimation of harbor tranquility. In this study, the significant wave heights from WTG were calibrated using measured data from AWAC and Waverider buoys moored at the same four locations with the WTG. It was observed that the product of significant wave height and peak wave period, HT, was not underestimated but linearly proportional between the measurements by two instruments. This linearity was applied to develop 3^rd order polynomial functions that best represented the relationship between HT and significant wave heights measured by WTG. These functions were then applied to calibrate the WTG significant wave heights that were lower than 0.7 m, the critical value established for the low waves in this study. The results showed that the linearity between the AWAC (or Waverider buoy) and calibrated wave heights were improved, and the magnitude of underestimated WTG wave heights were increased to be more realistic. The results of this study are expected to be effectively applied for other data sets obtained by WTG only, to increase the observation accuracy of WTG and to improve the estimation of harbor tranquility.

• Journal of Biosystems Engineering
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• v.20 no.2
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• pp.162-172
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• 1995

The ventilation in greenhouse have been important for such as adjustment of temperature, supplying of the oxygen, prevention of the overhumidity, density adjustment of $CO_2$, discharge of harmfulness gas, etc. However, the general ventilation which had been used the quantitative control method in discharge of a property of air mechanism in greenhouse, and caused mainly in waste of the heating energy and growth obstacle of the vegetable. Therefore, this study was peformed to obtain more scientific ventilation method using by analysis and measurement of the isothermal lines according to opening of window ventilation in greenhouse, and the results are summarized as follows. 1. The ventilating amount was more influenced by rather opening amount of window than the ventilating time. 2. In window ventilation, the temperature in greenhouse was mostly changed within 5 minutes after ventilating not regard to the spot of opening, after about 10 minutes temperature became to equilibrium state under the respective ventilating conditions. 3. In opening of the skylight only, isothermal lines were complicated, therefore, a tall vegetable may be possible to damage by a cold-weather from the lower central port in greenhouse. 4. Isothermal lines were a tendency to simply in opening of a side window that may be more effective ventilation in kinds of the short vegetable. 5. In conditions of internal temperature>setting temperature>external temperature, a skylight can be suitable to open 10~20cm in order to the optimum ventilation in greenhouse. 6. In conditions of internal temperature>external temperature>setting temperature, opening of all the windows or both the side windows that can be suitable in order to obtain the optimum ventilation in greenhouse. 7. An effect of ventilation was the most excellent to open of all the windows or both the side windows, and it were also found orderly excellent to open of the side window and the skylight or the skylight only, to open of the side window only. 8. Temperature was varied as the equation of T=Tc+ (To-Tc)e-at, and the ranges of (a) values were limited within 0.34~0.68. 9. A variations of humidity were similar to that of temperature, s.

• Journal of Adhesion and Interface
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• v.16 no.2
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• pp.69-75
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• 2015

Stone board for the rock bed was needed to reduce weight using thin thickness and reinforced materials. In this work, stone/wood board for rock bed was studied. Stone and wood were attached to reduce total weight of stone for rock bed. For reinforcing wood heat treatment method was used to change surface and mechanical properties. Mechanical strength of heat treated wood increased more than neat condition. The optimum heat treatment condition was set on $100^{\circ}C$ under tensile, flexural loads whereas surface energy was also obtained by contact angle measurement. Optimum adhesive condition was to get the maximum adhesion between stone and wood. Lap shear test was performed for stone/wood board with different adhesives such as amine type epoxy, polyurethane, chloro-rubber and vinyl chloride acetate type. Fracture surface of lap shear test was shown at wood fracture part on stone using amine type epoxy adhesive. It was found that for high adhesion between stone and wood the optimum adhesive was epoxy type for the rock bed.

• Journal of the East Asian Society of Dietary Life
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• v.15 no.6
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• pp.663-674
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• 2005

The factors for the childhood onset obesity were assessed to provide informations for the nutrition education program targeting the primary school children. The subjects of this study were 529 primary school children in Iksan City, Jeon-buk Province. Children were classified into obese(236) and control(293) groups by the obesity index. Anthropometric measurement dietary intake through 24-hour recall method, blood analysis and questionnaire response including nutritional knowledge and attitude, body image recognition and eating habits were conducted The mean age of subject was 12.0 years. The average body weight(p<0.001), BMI(p<0.001), and obesity index(p<0.001) in obese group were significantly different from those in control group; their values in the former were 26.5 kg/m2 and $37.7\%$ and 43.0 kg, 19.8 kg/m2 and $3.2\%$ in the latter, respectively. The average scores of self-satisfaction were significantly different in two groups (p<0.001), 31.2, and 34.1, respectively. Among the obese subjects, $60.6\%$ were unsatisfied or very unsatisfied with their body image, and $76.5\%$ had experiences of weight control and $67.5\%$ took diet control as a weight control method Among mothers of obese subjects, $89.1\%$ were unsatisfied with their children's body image. $64.4\%$ of obese subjects had obese parents. Average intake of energy were $76.7\%$ of RDA in obese group and $74.9\%$ of RDA in control group. Average intake of cereals(p<0.01), potatoes & starch(p<0.01) and eggs(p<0.01) between obese and control subjects were significantly different; 295.4g, 76.2g, 55.6g in the former and 277.9g, 38.1g, 45.6g in the latter, respectively. The mean serum triglyceride(p<0.05), GPT(p<0.05), hemoglobin(p<0.001) concentration of the obses and control subjects were significantly different; in the former, 103.6mg/dL, 24.6U/L, 13.4g/dL, and in the latter, 93.7mg/dL, 19.9U/L, 13.1g/dL, respectively, The results suggest that practical nutrition education for the prevention of childhood onset obese should be provided to primary school children.

• Journal of the Korean Chemical Society
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• v.7 no.2
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• pp.91-95
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• 1963

The basic studies of adsorption characteristics of collector on monazite were made by electrophoretic measurement and by determination of the adsorption of some typical flotation collectors. By above measurements made on monazite, it is concluded that $H^+\;and\;OH^-$ are identified to act as potential determining ions and thus the electrical properties of monazite is controlled by the pH of the solution. Therefore, anionic collectors are adsorbed on positively charged surfaces and cationic collectors on negatively charged surfaces, which in turn controls the effective flotation condition with respective collectors for this mineral. These results have been correlated with its flotation behavior obtained by Hallimond tube test.

• Clean Technology
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• v.17 no.3
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• pp.215-224
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• 2011

It is an important issue to develop quality assessing system for biofuel for the purpose of accelerating the mass production of biofuel. It is particularly challenging to conduct testing method in the mass production of bioethanol while meeting quality specifications such as ASTM (American Society for Testing & Materials) D4806-10. In order to address this challenge, this paper proposes on-line spectroscopic quality assesment system based on Near Infrared spectrum and Partial Least Squares method in Chemometrics. As a result of testing a number of preprocessing methods and Partial Least Squares, it was found out that Savitzky-Golay method showed the best performance in terms of spectrum correction, noise reduction, and model maintenance. The proposed system allows us to assess multiple quality components continuously using spectroscopic facilities with the cheap cost. Since the value of R2 is more than 0.99, it is possible to replace the laboratory analysis.

• Nuclear Engineering and Technology
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• v.4 no.4
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• pp.306-321
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• 1972

Molecular reorientation in (NH$_4$)$_2$SO$_4$, has been studied by cold neutron scattering. For T=300$^{\circ}$K data, the isolated quasielastic spectra and form-factors at various scattering angles are compared with four reorientational models based on SKOLD theory. Front these, it is concluded that the NH$_4$ions are performing either 3-fold four axes or 2-fold three axes reorientation with $\tau$$_{c}$=2.0$\times$10$^{-11}$ sec. The temperature dependence of f. is studied over 100$^{\circ}$K-413$^{\circ}$K and for the high-temperature phase, the widths of composite spectra are compared with the results from NMR relaxation measurements. All the results have shown that the neutron scattering method is capable of giving detalis of the reorientational modes in solids and therefore some discussions are given on the application of this method. A study of the form-factor is applied for NH$_4$I (Phase I) by comparing the measurement with the calculation based on free rotation approximation and proposed a reorientation model of NH$_4$ ions in the octahedral potential cage with $\tau$$_{c}$$\leq$10$^{-12}$ sec. Also a brief theoretical prediction for the effect of reorientational motions on the inelastic spectrum is discussed.sed.

• Journal of Korea Water Resources Association
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• v.46 no.12
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• pp.1249-1263
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• 2013

In order to minimize the damages caused by long-term drought, appropriate drought management plans of the basin should be established with the drought forecasting technology. Further, in order to build reasonable adaptive measurement for future drought, the duration and severity of drought must be predicted quantitatively in advance. Thus, this study, attempts to forecast drought in Korea by using an Artificial Neural Network Model, and drought index, which are the representative statistical approach most frequently used for hydrological time series forecasting. SPI (Standardized Precipitation Index) for major weather stations in Korea, estimated using observed historical precipitation, was used as input variables to the MLP (Multi Layer Perceptron) Neural Network model. Data set from 1976 to 2000 was selected as the training period for the parameter calibration and data from 2001 to 2010 was set as the validation period for the drought forecast. The optimal model for drought forecast determined by training process was applied to drought forecast using SPI (3), SPI (6) and SPI (12) over different forecasting lead time (1 to 6 months). Drought forecast with SPI (3) shows good result only in case of 1 month forecast lead time, SPI (6) shows good accordance with observed data for 1-3 months forecast lead time and SPI (12) shows relatively good results in case of up to 1~5 months forecast lead time. The analysis of this study shows that SPI (3) can be used for only 1-month short-term drought forecast. SPI (6) and SPI (12) have advantage over long-term drought forecast for 3~5 months lead time.

• Journal of the Mineralogical Society of Korea
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• v.23 no.3
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• pp.199-209
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• 2010

Coal gasification technology in the sector of domestic clean coal technologies is being into the limelight since recent dramatic rise of international oil price. In this study, we used a low rank coal from Inner Mongolia, China as a starting material for gasification. Various properties including optical, mineralogical, X-ray spectroscopic, X-ray diffraction, and drying property were measured and tested in order to estimate the suitability of the coal to gasification. The coal was identified as a brown coal of lignite group from the measurement of vitrinite reflectance. The coal has very low slagging and fouling potentials, and the ignition temperature is about $250^{\circ}C$. The major impurities consist of quartz, siderite, and clay minerals. Additionally, the coal had moisture content above 28%. Tests for finding effective drying method showed that the microwave drying is more effective than thermal drying.

• The Journal of the Korea Contents Association
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• v.12 no.6
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• pp.353-360
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• 2012

The purpose of this study was to determine whether there are relationships between radiologic parameters for osteoporosis by the proximal femur radiograhps and bone mineral density, as assessed by Dual Energy X-ray Absorptiometry(DEXA). Proximal femur anterior-posterior projection were taken from 112 individuals who undergoing DEXA. Radiographic parameters including canal-to-calcar ratio(CCR) and cortical thickness indices(CTI) were measured and compared with bone mineral density($g/cm^2$), T-score. The intramedullary femoral canal width(FW) and calcar width(CW) at osteoporosis group was significantly larger than that of control group. The CCR were correlated negatively with bone mineral density($g/cm^2$)(r=-0.340, p<0.01), and the CTI were correlated positively(r=0.624). The diagnostic accuracy of CCR for osteoporosis was 63.4%, and kappa value was 0.271. And the accuracy of CTI was 67.0%, and kappa value was the level of fair agreement(${\kappa}$=0.258). The proximal femur with large CCR and small CTI had lower T-scores. When evaluating proximal femur anterior-posterior radiographs, those patients with the thinnest femur diaphyseal cortices should be referred for further osteoporosis investigation.