• International Journal of Reliability and Applications
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• v.10 no.1
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• pp.43-57
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• 2009

In this article, we study the reliability equivalence factor of a series system. The failure rates of the system components are functions of time t. we study two cases of non-constat failure rates (i) weibull distribution (ii) linear increasing failure rate distribution. There are two methods are used to improve the given system. Two types of reliability equivalence factors are discussed. Numerical examples are presented to interpret how one can utilize the obtained results.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.930-932
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• 2007

In order to understand the doping control for the belt source evaporation, the Alq3 and NPB were codeposited on the Ta plate to re-sublimate. The very slow heating $(0.1^{\circ}C/s)$ of the Ta plate shows the separated rate signals of Alq3 and NPB sublimated from the Alq3-mixed NPB organic film on Ta plate. The ratio of the vapor rates of Alq3 and NPB was measured as same as that of each sublimation rates. Therefore, the doping control of the belt source evaporation is of the ratio of the vaporization rates of host and dopants.

• Journal of the Chungcheong Mathematical Society
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• v.33 no.1
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• pp.19-32
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• 2020

We discuss the coexistence of positive solutions to certain strongly-coupled predator-prey elliptic systems under the homogeneous Dirichlet boundary conditions. The sufficient condition for the existence of positive solutions is expressed in terms of the spectral property of differential operators of nonlinear Schrödinger type which reflects the influence of the domain and nonlinearity in the system. Furthermore, applying the obtained results, we investigate the sufficient conditions for the existence of positive solutions of a predator-prey system with degenerate diffusion rates.

• Journal of the Korean Ceramic Society
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• v.27 no.5
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• pp.693-697
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• 1990

TIACA has two different side groups(ligands) as iso-propoxy groups and acetylacetonate groups. These two side groups have different hydrolysis rates. The two different rates of hydrolysis confer unique properties on TIACA, which are stability in aqueous solution and easy preparation of TiO2 and its multi components gels without precipitation. Their hydrolysis rates were monitored with I.R. and U.V. spectrophotometer.

• Communications for Statistical Applications and Methods
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• v.11 no.3
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• pp.495-501
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• 2004

HJM representation of the term structure of interest rates sometimes produces the negative interest rates with positive probability. This paper shows that the condition of positive interest rates can be derived from the jump diffusion process, if a proper positive martingale process with the compensated jump process is chosen. As in Flesaker and Hughston, the condition is incorporated into the bond price process.

• Journal of the Chungcheong Mathematical Society
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• v.34 no.2
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• pp.157-168
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• 2021

This study uses the benchmark interest rate of the Federal Open Market Committee (FOMC) to predict gold futures prices. For the predictions, we used the support vector machine (SVM) (a machine-learning model) and the long short-term memory (LSTM) deep-learning model. We found that the LSTM method is more accurate than the SVM method. Moreover, we applied the Boruta algorithm to demonstrate that the FOMC benchmark interest rates correlate with gold futures.

• Korean Journal of Agricultural Science
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• v.38 no.1
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• pp.129-143
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• 2011

In this study, to select the incoming solar radiation equation which is most suitable for the estimation of Penman evaporation, 12 incoming solar radiation equations were selected. The Penman evaporation rates were estimated using 12 selected incoming solar radiation equations, and the estimated Penman evaporation rates were compared with measured pan evaporation rates. The monthly average daily meteorological data measured from 17 meteorological stations (춘천, 강능, 서울, 인천, 수원, 서산, 청주, 대전, 추풍령, 포항, 대구, 전주, 광주, 부산, 목포, 제주, 진주) were used for this study. To evaluate the reliability of estimated evaporation rates, mean absolute bias error(MABE), root mean square error(RMSE), mean percentage error(MPE) and Nash-Sutcliffe equation were applied. The study results indicate that to estimate pan evaporation using Penman evaporation equation, incoming solar radiation equation using meteorological data such as precipitation, minimum air temperature, sunshine duration, possible duration of sunshine, and extraterrestrial radiation are most suitable for 11 study stations out of 17 study stations.

• Journal of Ecology and Environment
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• v.37 no.3
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• pp.139-145
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• 2014

Denitrification permanently removes nitrate from aquatic ecosystems, so construction of denitrification walls to enhance denitrification activity is often suggested to reduce the nitrate levels from tributary ecosystems. However, little information is available to guide the choice of appropriate organic materials for increasing denitrification rates in the walls. This study investigated how differences in organic substrates originating from litter and organic materials affected denitrification and carbon mineralization rates in riparian sediments. Potential denitrification rates were highest in riparian sediments that contained large quantities of extractable organic carbon (Ext. Org C) and that had high anaerobic carbon mineralization rates, but they were negatively correlated with C:N ratios. Therefore, this research suggested that the both carbon quantity and quality should be considered when assessing the efficiency of organic substrates to remove nitrate from tributary ecosystems.

• English Language & Literature Teaching
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• v.18 no.1
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• pp.69-89
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• 2012

This paper explored the effects of extensive reading (ER) on Korean university students' L2 reading proficiency and reading rates. This study also illustrated how ER can be integrated into a university English reading class. Seventeen students who took a summer reading course participated in this study. Data were gathered through pre- and post- tests in terms of participants' reading comprehension proficiency and reading rates and post- questionnaire with regard to their attitudes toward L2 storybook reading after they have experienced it. The analysis was carried out using the Paired Samples t-test. It was revealed that ER has a positive effect on the enhancement of the participants' reading comprehension and reading rates. The participants showed their continued intention to read in English and a strong belief that persistent reading in English in the long run will help improve their English. The results of this study confirm the educational values of incorporating ER into university English reading classes. The pedagogical implications for EFL instructors are described.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.552-555
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• 2002

Wideband CDMA is one of the radio access technologies for the third generation in which voice is the basic service. There has been lot of research work in order to find out the suitable transmission scheme to meet the requirement of accommodating variable type of services in Wideband-CDMA. This paper studies the behavior of different services using different transmission schemes in Wideband CDU and compares their performance in terms of BER. Different transmission schemes are found to be suitable for different services. Transmission schemes used are- fixed processing gain scheme also called as variable bandwidth scheme, single code transmission and multicode transmission. It is found that fixed processing gain scheme is suitable fur high data rates. Single code transmission is suitable fer low data rates where as multicode transmission is suitable for low and medium data rates.