• Journal of Distribution Science
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• v.11 no.10
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• pp.63-72
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• 2013

Purpose - This study analyzes the relationship and dynamic interactions between stock price index, interest rate, price index, and housing price indices using Korean monthly data from 2000 to 2013, based on a VAR model. This study also examines Granger causal relationships among these variables in order to determine whether the time series of one is useful in forecasting another, or to infer certain types of causal dependency between stochastic variables. Research design, data, and methodology - We used Korean monthly data for all variables from 2000: M1 to 2013: M3. First, we checked the correlations among different variables. Second, we conducted the Augmented Dickey-Fuller (ADF) test and the co-integration test using the VAR model. Third, we employed Granger Causality tests to quantify the causal effect from time series observations. Fourth, we used the impulse response function and variance decomposition based on the VAR model to examine the dynamic relationships among the variables. Results - First, stock price Granger affects interest rate and all housing price indices. Price index Granger, in turn, affects the stock price and six metropolitan housing price indices. However, none of the Granger variables affect the price index. Therefore, it is the stock markets (and not the housing market) that affects the housing prices. Second, the impulse response tests show that maximum influence on stock price is its own, and though it is influenced a little by interest rate, price index affects it negatively. One standard deviation (S.D.) shock to stock price increases the housing price by 0.08 units after two months, whereas an impulse shock to the interest rate negatively impacts the housing price. Third, the variance decomposition results report that the shock to the stock price accounts for 96% of the variation in the stock price, and the shock to the price index accounts for 2.8% after two periods. In contrast, the shock to the interest rate accounts for 80% of the variation in the interest rate after ten periods; the shock to the stock price accounts for 19% of the variation; however, shock to the price index does not affect the interest rate. The housing price index in 10 periods is explained up to 96.7% by itself, 2.62% by stock price, 0.68% by price index, and 0.04% by interest rate. Therefore, the housing market is explained most by its own variation, whereas the interest rate has little impact on housing price. Conclusions - The results of the study elucidate the relationship and dynamic interactions among stock price index, interest rate, price index, and housing price indices using VAR model. This study could help form the basis for more appropriate economic policies in the future. As the housing market is very important in Korean economy, any changes in house price affect the other markets, thereby resulting in a shock to the entire economy. Therefore, the analysis on the dynamic relationships between the housing market and economic variables will help with the decision making regarding the housing market policy.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.60 no.1
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• pp.85-90
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• 2015

The objective of this study was comparison of seed yields according to different seeding rates, seeding time and application of chemical fertilizations in Yanji region of China. The experiment was conducted on commercial farmland at Yanji region in 2013. All the experimental fields were designed following randomized block design with 3 replicates. The plant spacing was applied as $65{\times}1cm$ distance. To check the effect of seeding rate, two different seeding rate, 0.2 kg/0.1ha and 0.5 kg/0.1ha were applied. The higher seed yield was observed in low seeding rate (0.2 kg/0.1ha). The application of fertilizer (mixture of N and P) showed different results following different experimental fields. However, there were little positive effects following fertilizer application into commercial farmland. When we compare seed yields between two different seeding dates, $4^{th}$ May and $29^{th}$ May, the earlier seeding date ($4^{th}$ May) showed higher seed yields. In considering these results, low seeding rate and early seeding time is important for getting high camelina seed yields.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.04a
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• pp.835-841
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• 2013

Modern solid-state gyroscopes (HRG) with hemispherical resonators from high-purity quartz glass and special surface superfinishing and ultrathin gold coating become the best instruments for precise-grade inertial reference units (IRU) targeting long-term space missions. Designing of these sensors could be a notable contribution into development of Korea as a space nation. In participial, 40mm diameter thin-shell resonator from high-purity fused quartz, fabricated as a single-piece with its supporting stem has been designed, machined, etched, tuned, tested, and delivered by STM Co. (ATS of Ukraine) several years ago; an extremely-high Q-factor (upto 10~20 millions) has been shown. Understanding of the best way how to match such a unique sensor with inner glass assembly of the gyro means how to use the high potential in a maximal extent; and this has become the urgent task. Inner quartz glass assembly has a very thin indium (In) layer soldered the resonator and its silica base (case), but effects of internal resonances between operational modal pair of the shell-cup and its side (parasitic) modes can notable degrade the potential of the sensor as a whole, instead of so low level of resonator's intrinsic losses. Unfortunately, there are special combinations of dimensions of the parts (so-called, "resonant sizes"), when intensive losses of energy occurs. The authors proposed to use the length of stem's fixture as an additional design parameter to avoid such cases. So-called, a cyclic scheme of finite element method (FEM) and ANSYS software were employed to estimate different combinations of gyro assembly parameters. This variant has no mismatches of numerical origin due to FEM's discrete mesh. The optimum length and dangerous "resonant lengths" have been found. The special attention has been paid to analyses of 3D effects in a cup-stem transient zone, including determination of a difference between the positions of geometrical Pole of the resonant hemisphere and of its "dynamical Pole", i.e., its real zone of oscillation node. Boundary effects between the shell (cup) and 3D short "beams" (inner and outer stems) have been ranged. The results of the numerical experiments have been compared with the classic model of a quasi-hemispherical shell band with inextensional midsurface, and the solution using Rayleigh's functions of the $1^{st}$ and $2^{nd}$ kinds. To guarantee the truth of the recommended sizes to a designer of the real device, the analytical and FEM results have been compared with experimental data for a party of real resonators. The consistency of the results obtained by different means has been shown with errors less than 5%. The results notably differ from the data published earlier by different researchers.

• Korean Journal of Food Science and Technology
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• v.41 no.3
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• pp.245-250
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• 2009

This study examined the optimization of alcohol extraction conditions for maximizing the total polyphenols derived from apple pomace, by response surface methodology (RSM). The effects of four independent variables, including $X_1$ (ratio of solvent to sample content), $X_2$ (dipping time), $X_3$ (extraction time), and $X_4$(extraction temperature), were investigated at five levels using central composite design (CCD). $Y_1$ (yield) and $Y_2$ (total polyphenols) were chosen as dependent variables. The coefficients of determination, $R^2$, were greater than 0.900 (0.9042 and 0.9555). The results showed that the model fit was very significant (p<0.001). The optimum extraction conditions were as follows: 13.00 mL/g for the ratio of solvent to sample content, 89.02 min for dipping time, 180 min for extraction time, and $70^{\circ}C$ for extraction temperature. At these conditions, the predicted total polyphenol content was 29.68 mg catechin equiv./g.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.36 no.4
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• pp.329-336
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• 2000

Welding is a important technological method in mechanical engineering. $CO_2$MAG(metal active gas) welding means that metal part in double capstan drum for the inshore and costal vessels are joined by melting(with or without a filler material) or that new material is added to a metal part by melting. The thermal stresses appear due to a non-uniform temperature field, inhomogeneous material properties, external restraint and volume changes during phase transformations. In this study analysis the elasto-plastic thermal stresses distribution of welding part in double capstan drum for the inshore and costal vessels using finite element method (FBM). Therefore it calculates the numerical value that can be applied to the optimum design of welding parts and the shapes. The significant results obtained in this study are summarized as fellows. At early stage of the cooling after welding process, the abrupt thermal stresses gradient has been shown in the vicinity of welding part. In the thermal stresses analysis due to temperature gradient and heat shocking maximum stress was occurred of welding part and stresses were distributed from 54MPa~48MPa.

• International Journal of Highway Engineering
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• v.17 no.3
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• pp.49-58
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• 2015

PURPOSES : The use of environmentally friendly construction methods has been recently encouraged to reduce fuel consumption and the effects of global warming. For this purpose, the roller compacted concrete pavement (RCCP) construction method has been developed. RCCP is more environmentally friendly and economically efficient than general concrete by reducing the amount of CO2 generated through the application of a smaller amount of cement. RCCP has a number of advantages such as an easy construction method, low cost, high structural hydration performance, and aggregate interlocking. However, mix design standards and construction guidelines of RCCP are required for domestic application. In addition, a study on aggregate selection, which has an effect on the characteristics of RCCP, is necessary owing to a limited number of researches. Thus, the aggregate effect on the performance of RCCP in securing the required strength and workability was evaluated in consideration of domestic construction. METHODS : Sand and coarse aggregates of both 19mm and 13mm in maximum size were used in this study. Four types of aggregate gradations (s/a = 30%, 58%, and 70% for the sand and coarse aggregate of 19mm in maximum size, and s/a = 50% for a combination of the three types of aggregates) were set up to investigate the effects of the PCA band on the RCC characteristics. The conditions of s/a = 30% and 70% were evaluated to check the gradation effect outside of the recommended band. The conditions of s/a = 58% and 50% were used because they are the optimum combination of the two and three types of aggregates, respectively. RCCP gradation band was suggested gradation with a proper construction method of RCCP by synthetically comparing and analyzing the correlation of optimum water content, maximum dry density, and strength of requirements through its consistency and compaction test. RESULTS : The lower and upper limit lines are insufficient to secure a relatively strong development and workability compared to an aggregate gradation in the RCCP gradation band region. On the other hand, the line in the RCCP gradation band and the 0.45 power curve in the RCCP gradation band region were satisfactory, ensuring the required strength and workability. CONCLUSIONS : The suitable aggregate gradation on RCCP process should meet the RCCP gradation band area; however, fine particles passing through a #60 sieve do not need to be within the recommended gradation band because the influence of this region on such fine particles is small.

• Water for future
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• v.29 no.2
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• pp.249-260
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• 1996

There have been easily found a number of examples that misleading or unreasonable measuring data set of physical variables are often produced in the field and the laboratory. The primary reason is that the specific requirements of civil engineers are initially disregarded in designing the experimental apparatus. It results from a lack of mutual understanding and co-operating between the user group and the maker. Therefore, their fundamental knowledge and apprehension become indispensible in order to obtain measuring data with high confidence and good quality In this study it is shortly explained the basic structure and the operation system of the experimental equipments commonly used at the present. A simple measuring set is developed which is quite easy for a general civil engineer to design and operate without any other specialty of mostly electricity electronics. Based upon this requirement, one of data logger named PPDL8 is newly designed by making use of the parallel port in the personal computer, consisting of multi-channels able to measure 8 different point values simultaneously. It can also use many valuable sub-programs existing in PC because the user makes his own programs necessary for measurement, by himself. Of all things, it has a great advantage to increase the applicability of field measurements much larger when adopting the notebook computer to operate with small battery only. In addition this study gives, in fact, the excellent agreements of in-situ field variables by showing their measuring results of temperature, distance and turbidity.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.434-435
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• 2012

Plasma enhanced chemical vapor deposition (PECVD) silicon dioxide thin films have many applications in semiconductor manufacturing such as inter-level dielectric and gate dielectric metal oxide semiconductor field effect transistors (MOSFETs). Fundamental chemical reaction for the formation of SiO2 includes SiH4 and O2, but mixture of SiH4 and N2O is preferable because of lower hydrogen concentration in the deposited film [1]. It is also known that binding energy of N-N is higher than that of N-O, so the particle generation by molecular reaction can be reduced by reducing reactive nitrogen during the deposition process. However, nitrous oxide (N2O) gives rise to nitric oxide (NO) on reaction with oxygen atoms, which in turn reacts with ozone. NO became a greenhouse gas which is naturally occurred regulating of stratospheric ozone. In fact, it takes global warming effect about 300 times higher than carbon dioxide (CO2). Industries regard that N2O is inevitable for their device fabrication; however, it is worthwhile to develop a marginable nitrous oxide free process for university lab classes considering educational and environmental purpose. In this paper, we developed environmental friendly and material cost efficient SiO2 deposition process by substituting N2O with O2 targeting university hands-on laboratory course. Experiment was performed by two level statistical design of experiment (DOE) with three process parameters including RF power, susceptor temperature, and oxygen gas flow. Responses of interests to optimize the process were deposition rate, film uniformity, surface roughness, and electrical dielectric property. We observed some power like particle formation on wafer in some experiment, and we postulate that the thermal and electrical energy to dissociate gas molecule was relatively lower than other runs. However, we were able to find a marginable process region with less than 3% uniformity requirement in our process optimization goal. Surface roughness measured by atomic force microscopy (AFM) presented some evidence of the agglomeration of silane related particles, and the result was still satisfactory for the purpose of this research. This newly developed SiO2 deposition process is currently under verification with repeated experimental run on 4 inches wafer, and it will be adopted to Semiconductor Material and Process course offered in the Department of Electronic Engineering at Myongji University from spring semester in 2012.

• Journal of Animal Science and Technology
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• v.54 no.3
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• pp.175-183
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• 2012

The present study was conducted to investigate the relationships of muscle fiber characteristics to dietary energy density [3.0(Low-E) vs. 3.2 (Med-E) Mcal DE/kg)] and slaughter weight [SW; 110, 125, and 138 kg] in finishing pigs (gilt vs. barrow) using a $2{\times}3{\times}2$ factorial treatment design. Forty-one longissimus dorsi muscle (LM) samples were analyzed histochemically, with growth performance and physicochemical data for the 41 animals and their LM out of 192 animals and 72 LM used in a previous study retrospectively included. The ADG was less (P<0.01) in the Low-E than in the Med-E group (0.93 vs. 0.73 kg) whereas lightness ($L^*$) and redness ($a^*$) of LM were greater in the Low-E group SW did not influence these variables. The diameter and perimeter of the type I (slow-oxidative), type IIA (fast oxido-glycolytic) and type IIB (fast glycolytic) fibers increased with increasing SW whereas densities of the fibers decreased. However, the number and area percentages of the fiber types were not influenced by SW or dietary energy density. The percentage and per-$mm^2$ density of type IIB fibers were negatively correlated with SW (r = -0.33 and -0.57, with P<0.05 and <0.01, respectively), whereas type I fiber number percentage was positively correlated with SW (r = 0.31; P<0.05). Marbling score was negatively correlated (P<0.05) with type I (r = -0.36) and type IIB (r = -0.39) fiber densities. The $a^*$ was correlated (P<0.01) with both type I and type IIB fiber number percentages in the opposite way (r = 0.42 and -0.47, respectively). However, $L^*$ (lightness), drip loss and $pH_{24h}$ were not correlated with the fiber number percentage or density of any fiber type. Collectively, results indicate that muscle fibers grow by hypertrophy during the late finishing period, but that fiber characteristics other than the size are not significantly influenced by dietary energy density or SW.

• Journal of Pharmaceutical Investigation
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• v.37 no.5
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• pp.315-321
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• 2007

The purpose of the present study was to evaluate the bioequivalence of two lercanidipine hydrochloride tablets, Zanidip tablet (LG Life Sciences Ltd., Korea, reference drug) and Samchundang Lercanidipine tablet 10 mg (Sam Chun Dang Pharm. Co. Ltd., Korea, test drug), according to the guidelines of Korea Food and Drug Administration (KFDA). After adding an internal standard (amlodipine maleate) to human serum, serum samples were extracted using hexan-isoamyl alcohol (100:1, v/v). Compounds were analyzed by liquid chromatography/tandem mass spectrometry. This method showed linear response over the concentration range of 0.05-20 ng/mL with correlation coefficient of 0.9999. The lower limit of quantitation using 0.5 mL of serum was 0.05 ng/mL which was sensitive enough for pharmacokinetic studies. Thirty healthy male Korean volunteers received each medicine at the lercanidipine hydrochloride dose of 20 mg in a $2\;{\times}\;2$ crossover study. There was a one-week washout period between the doses. Serum concentrations of lercanidipine were monitored by an LC/MS/MS fer over a period of 24 hr after the administration. $AUC_t$ (the area under the serum concentration-time curve from time 0 to 24 hr) was calculated by the linear trapezoidal rule method. $C_{max}$ (the maximum serum drug concentration) and $T_{max}$ (the time to reach $C_{max}$) were compiled from the serum concentration-time data. Analysis of variance was carried out using logarithmically transformed $AUC_t$ and $C_{max}$. No significant sequence effect was found for all of the bioavailability parameters, indicating that the crossover design was properly performed. The 90% confidence intervals of the $AUC_t$ ratio and the $C_{max}$ ratio for Samchundang Lercanidipine/Zanidip were log 0.9505-log 1.2258 and log 0.9987-log 1.2013, respectively. These values were within the acceptable bioequivalence intervals of log 0.80-log 1.25. Thus, the criteria of the KFDA guidelines for the bioequivalence was satisfied, indicating Samchundang Lercanidipine tablet 10 mg and Zanidip tablet are bioequivalent.