• Journal of Environmental Science International
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• v.27 no.12
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• pp.1169-1178
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• 2018

Two man-made carbon emissions, fossil fuel emissions and land use emissions, have been perturbing naturally occurring global carbon cycle. These emitted carbons will eventually be deposited into the atmosphere, the terrestrial biosphere, the soil, and the ocean. In this study, Simple Global Carbon Model (SGCM) was used to simulate global carbon cycle and to estimate global carbon budget. For the model input, fossil fuel emissions and land use emissions were taken from the literature. Unlike fossil fuel use, land use emissions were highly uncertain. Therefore land use emission inputs were adjusted within an uncertainty range suggested in the literature. Simulated atmospheric $CO_2$ concentrations were well fitted to observations with a standard error of 0.06 ppm. Moreover, simulated carbon budgets in the ocean and terrestrial biosphere were shown to be reasonable compared to the literature values, which have considerable uncertainties. Simulation results show that with increasing fossil fuel emissions, the ratios of carbon partitioning to the atmosphere and the terrestrial biosphere have increased from 42% and 24% in the year 1958 to 50% and 30% in the year 2016 respectively, while that to the ocean has decreased from 34% in the year 1958 to 20% in the year 2016. This finding indicates that if the current emission trend continues, the atmospheric carbon partitioning ratio might be continuously increasing and thereby the atmospheric $CO_2$ concentrations might be increasing much faster. Among the total emissions of 399 gigatons of carbon (GtC) from fossil fuel use and land use during the simulation period (between 1960 and 2016), 189 GtC were reallocated to the atmosphere (47%), 107 GtC to the terrestrial biosphere (27%), and 103GtC to the ocean (26%). The net terrestrial biospheric carbon accumulation (terrestrial biospheric allocations minus land use emissions) showed positive 46 GtC. In other words, the terrestrial biosphere has been accumulating carbon, although land use emission has been depleting carbon in the terrestrial biosphere.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.408-412
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• 2009

In this paper, a new efficient algorithm for global motion estimation is proposed. This algorithm uses a previous 4-parameter model based global motion estimation algorithm and M-estimator for improving the accuracy and robustness of the estimate. The first algorithm uses the block based motion vector fields and which generates a coarse global motion parameters. And second algorithm is M-estimator technique for getting precise global motion parameters. This technique does not increase the computational complexity significantly, while providing good results in terms of estimation accuracy. In this work, an initial estimation for the global motion parameters is obtained using simple 4-parameter global motion estimation approach. The parameters are then refined using M-estimator technique. This combined algorithm shows significant reduction in mean compensation error and shows performance improvement over simple 4-parameter global motion estimation approach.

• International Commerce and Information Review
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• v.14 no.4
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• pp.153-174
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• 2012

The purpose of this study is to analyse factors affecting performance of Global Outsourcing of the Korean Export-Importing Companies. This study aims to confirm the cause and effect relationship between independent variables; Organization Competency, Flexibility, Information Sharing and Partnership and dependent variable; the performance of Global Outsourcing. Also, another objective of this study is to discover affecting levels for the performance and activation factors of global outsourcing and to contribute to diffusion of global sourcing. This paper examined the concept and features of global sourcing and the present situation of global outsourcing at the level of domestic and overseas. From precedent studies that based on empirical studies about the transaction theory and the resource-based theory, we have derived a model with hypothesis and scale items then we conducted a survey of the Korean Export-Importing companies and empirically analysed the data. Before hypothesis testing, we conducted a basic information analysis in order to discover implication level of Global Soucring and also did reliability analysis and exploratory factor analysis using SPSS 18.0. Finally, the four hypothesis for the performance of Global Sourcing were tested with a regression model.

• International conference on construction engineering and project management
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• 2017.10a
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• pp.1-7
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• 2017

Korea's domestic construction market and overseas construction order environment are experiencing a decreasing trend, and this trend is expected to continue. Therefore, domestic construction companies are seeking to enter the global construction market. This study analyzes the global construction market and the global competitiveness for global construction companies and provides the results. To this end, this study has developed a model to evaluate the global construction competitiveness level and to evaluated global construction competitiveness in 2016. The evaluation of global construction competitiveness was analyzed based on the competitiveness of construction infrastructure by country, and the evaluation results of competitiveness of construction companies. These assessments were based on 20 detailed international statistics (ENR, Global Insight, Compass, etc.). The evaluation results are as follows. First, in regard to the comprehensive global construction competitiveness by country, America ranked first among 20 countries, followed by China. European countries like Spain, Germany and the Netherlands ranked third to fifth, respectively. Korea ranked sixth, one rank higher than that of the previous year. America and European countries remain strong. Second, in regard to the comprehensive building infrastructure competitiveness by country, America ranked first followed by Germany. Korea ranked twelfth, which is the same rank as that of the previous year. When it comes to stability in the construction market, China ranked first and Korea eighth. For construction systems, Sweden ranked first and Korea thirteenth, and for infrastructure, Japan ranked first and Korea tenth. Third, according to the construction company's capability evaluation by country, America ranked first followed by China. Korea ranked fourth, two ranks higher than that of the previous year because of its building competitiveness (fifth → fourth) and design competitiveness (eleventh → eighth) which has improved. When it comes to building competitiveness, China ranked first and Korea fourth. For design competitiveness, America ranked first and Korea eighth, and for price competitiveness, India ranked first and Korea seventh. However, Korea is still in the middle of the pack rank among the 20 countries considered when it comes to design competitiveness. It is ranked eleventh for design productivity and thirteenth for foreign sales against the total sales (internationalization). Thus, Korea needs to improve technical power and tap into new markets for improved competitiveness, including increased productivity. To do so, more R&D investment is required.

• Journal of applied mathematics & informatics
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• v.25 no.1_2
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• pp.363-374
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• 2007

In this paper, we consider the discrete nonlinear delay model which describe the control of a single population of cells. We establish a sufficient condition for oscillation of all positive solutions about the positive equilibrium point and give a sufficient condition for the global attractivity of the equilibrium point. The oscillation condition guarantees the prevalence of the population about the positive steady sate and the global attractivity condition guarantees the nonexistence of dynamical diseases on the population.

• Journal of applied mathematics & informatics
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• v.7 no.3
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• pp.925-940
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• 2000

The spatial spread of a disease in an SIRS epidemic model with immunity imparted by subclinical infection on a population has been considered. The incidence rate of infection and the rate of immunization are both of nonlinear type. The dynamics of the infectious disease and its endemicity in local and global sense have been investigated.

• Journal of applied mathematics & informatics
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• v.27 no.5_6
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• pp.1097-1107
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• 2009

In this paper, three species stage-structured predator-prey model with time delayed and periodic constant impulsive perturbations of predator at fixed times is proposed and investigated. We show that the conditions for the global attractivity of prey(pest)-extinction periodic solution and permanence of the system. Our model exhibits a new modelling method which is applied to investigate impulsive delay differential equations. Our results give some reasonable suggestions for pest management.

• Journal of applied mathematics & informatics
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• v.28 no.5_6
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• pp.1089-1099
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• 2010

An SIR epidemic model with pulse vaccination and time delay describing infection period is investigated. The global attractiveness of the infection-free periodic solution is discussed, and sufficient condition is obtained for the permanence of the system. Our results indicate that a large vaccination rate or a short period of pulsing leads to the eradication of the disease.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.475-478
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• 2015

The objective of this study is to apply a hybrid model for estimating solar radiation and investigate their accuracy. A hybrid model is wavelet-based support vector machines (WSVMs). Wavelet decomposition is employed to decompose the solar radiation time series into approximation and detail components. These decomposed time series are then used as inputs of support vector machines (SVMs) modules in the WSVMs model. Results obtained indicate that WSVMs can successfully be used for the estimation of daily global solar radiation at Champaign and Springfield stations in Illinois.

• Journal of the Korean earth science society
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• v.38 no.2
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• pp.129-140
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• 2017

Global solar radiation was calculated in this research using ground-base measurement data, meteorological satellite data, and GWNU (Gangneung-Wonju National University) solar radiation model. We also analyzed the accuracy of the GWNU model by comparing the observed solar radiation according to the total cloud cover. Our research was based on the global solar radiation of the GWNU radiation site in 2012, observation data such as temperature and pressure, humidity, aerosol, total ozone amount data from the Ozone Monitoring Instrument (OMI) sensor, and Skyview data used for evaluation of cloud mask and total cloud cover. On a clear day when the total cloud cover was 0 tenth, the calculated global solar radiations using the GWNU model had a high correlation coefficient of 0.98 compared with the observed solar radiation, but root mean square error (RMSE) was relatively high, i.e., $36.62Wm^{-2}$. The Skyview equipment was unable to determine the meteorological condition such as thin clouds, mist, and haze. On a cloudy day, regression equations were used for the radiation model to correct the effect of clouds. The correlation coefficient was 0.92, but the RMSE was high, i.e., $99.50Wm^{-2}$. For more accurate analysis, additional analysis of various elements including shielding of the direct radiation component and cloud optical thickness is required. The results of this study can be useful in the area where the global solar radiation is not observed by calculating the global solar radiation per minute or time.