• Journal of Environmental Science International
• /
• v.1 no.1
• /
• pp.35-43
• /
• 1992

Handling the emergency problems such as Chemobyl accident require real time prediction of pollutants dispersion. One-point real time sounding at pollutant source and simple model including turbulent-radiation process are very important to predict dispersion at real time. The stability categories obtained by one-dimensional numerical model (including PBL dynamics and radiative process) are good agreement with observational data (Golder, 1972). Therefore, the meteorological parameters (thermal, moisture and momentum fluxes; sensible and latent heat; Monin-Obukhov length and bulk Richardson number; vertical diffusion coefficient and TKE; mixing height) calculated by this model will be useful to understand the structure of stable boundary layer and to handling the emergency problems such as dangerous gasses accident. Especially, this simple model has strong merit for practical dispersion models which require turbulence process but does not takes long time to real predictions. According to the results of this model, the urban area has stronger vertical dispersion and weaker horizontal dispersion than rural area during daytime in summer season. The maximum stability class of urban area and rural area are "A" and "B" at 14 LST, respectively. After 20 LST, both urban and rural area have weak vertical dispersion, but they have strong horizontal dispersion. Generally, the urban area have larger radius of horizontal dispersion than rural area. Considering the resolution and time consuming problems of three dimensional grid model, one-dimensional model with one-point real sounding have strong merit for practical dispersion model.al dispersion model.

• Journal of Environmental Science International
• /
• v.11 no.7
• /
• pp.663-667
• /
• 2002

The aerodynamic resistance($R_a$) to vertical transfer in the surface boundary layer can be formulated in terms of the friction velocity, height of observation, vertical heat flux and surface roughness. Unlike previous studies which focused on the role of $R_c$, present study perform additional tests using a variety of $R_a$ formulae. Several $R_a$ formulations available in the literature, suitable for unstable conditions, were tested for their influence on the dry deposition velocity. The canopy resistance($R_c$) determines the shape of the diurnal pattern, while a small amplitude diurnal cycle in $V_d$ was attributed to the aerodynamic resistance. The aerodynamic resistance is the major contributor to the formation of spikes in nighttime and $R_a$ is relatively important at night because the canopy resistance is smaller. All formulations show similar diurnal cycle and yield good agreement with the observations. Although present $V_d$ formulations are suitable for numerical air qualify models, the research must continue for further improvements in resistance parametrizations.

• Journal of Environmental Science International
• /
• v.12 no.9
• /
• pp.957-966
• /
• 2003

Gunsan coastal area is one of region increasing pollution problems. To improve water quality, the reduction of these nutrients loads should be indispensible. In this study, the three-dimensional numerical hydrodynamic and ecosystem model were applied to analyze the processes affecting the eutrophication. In field survey, the average concentrations of dissolved inorganic nitrogen (DIN) and dissolved inorganic phosphorus(DIP) at surface waters were found to be 0.43mg/$\ell$ and 0.03mg/$\ell$ respectively, which were exceeding second grade of water quality criteria. In hydrodynamic modelling, the comparison between the simulated and observed tidal ellipses showed fairly good agreement. The ecosystem model was calibrated with the observed data in study area. The simulated results of DIN were fairly good coincided with the observed values within relative error of 32.39%, correlation coefficient(r) of 0.99. In the case of DIP, the simulated results were fairly good coincided with the observed values within relative error of 24.26%, correlation coefficient(r) of 0.82. The simulations of DIN and DIP concentrations using ecosystem model were performed under the conditions of 20∼80% reductions for pollutant loading. At simulation results, concentration of DIN and DIP were reduced to 20∼80% and under 10% in case of the 80% reduction of pollutant loading, respectively.

• Journal of Environmental Science International
• /
• v.27 no.7
• /
• pp.531-541
• /
• 2018

Road freezing caused by snowfall during wintertime causes traffic congestion and many accidents. To prevent such problems, we developed, in this study, a system to predict road freezing based on weather forecast data and the freezing generation modules. The weather forecast data were obtained from a high-resolution model with 1 km resolution for Jeju Island from 00:00 KST on December 1, 2017, to 23:00 KST on February 28, 2018. The results of the weather forecast data show that index of agreement (IOA) temperature was higher than 0.85 at all points, and that for wind speed was higher than 0.7 except in Seogwipo city. In order to evaluate the results of the freezing predictions, we used model evaluation metrics obtained from a confusion matrix. These metrics revealed that, the Imacho module showed good performance in precision and accuracy and that the Karlsson module showed good performance in specificity and FP rate. In particular, Cohen's kappa value was shown to be excellent for both modules, demonstrating that the algorithm is reliable. The superiority of both the modules shows that the new system can prevent traffic problems related to road freezing in the Jeju area during wintertime.

• Journal of Environmental Science International
• /
• v.31 no.7
• /
• pp.617-635
• /
• 2022

The effect of coupled data assimilation (DA) on the meteorological prediction in the west coastal region of Korea was evaluated using a coupled atmosphere-ocean model (e.g., COAWST) in the spring (March 17-26) of 2019. We performed two sets of simulation experiments: (1) with the coupled DA (i.e., COAWST_DA) and (2) without the coupled DA (i.e., COAWST_BASE). Overall, compared with the COAWST_BASE simulation, the COAWST_DA simulation showed good agreement in the spatial and temporal variations of meteorological variables (sea surface temperature, air temperature, wind speed, and relative humidity) with those of the observations. In particular, the effect of the coupled DA on wind speed was greatly improved. This might be primarily due to the prediction improvement of the sea surface temperature resulting from the coupled DA in the study area. In addition, the improvement of meteorological prediction in COAWST_DA simulation was also confirmed by the comparative analysis between SST and other meteorological variables (sea surface wind speed and pressure variation).

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.19 no.2
• /
• pp.186-192
• /
• 2013

Because of the shallow depth of 44 m and large area of wetland in Korea and China, the class I productivity of Yellow Sea is very high (>300 $gC/m^2/year$), which is supporting substantial populations of fish, invertebrates, marine mammals and seabirds. However, the Yellow Sea is a large marine ecosystem which is enclosed by mainland of China and Korean peninsula, so it is vulnerable to external stress such as environmental degradation and overfishing. Recently, since the Fisheries Agreement between Korea and China, overfishing and illegal fishing of China and environmental degradation caused by coastal development in Korea and China have given much stress to the marine ecosystem of Yellow Sea. This article suggests that the major factors of governance are ineffectively responding to the growing demand for exploitation of the Yellow Sea and the international cooperation for establishing network of Yellow Sea governance is urgent.

• 한국정보교육학회:학술대회논문집
• /
• 2011.01a
• /
• pp.211-217
• /
• 2011

Recent IT (information technology) environmental changes, such as emerging social network services or increasing user participation in multimedia environment, have made it necessary for e-learning systems to undergo changes in various ways. Metadata is an agreement for interoperability between different systems. The standardization of metadata for e-learning system has been driven by some domestic and international organizations, but applying diverse environmental changes into the design of e-learning metadata is in dire need. In this paper, we present a methodology for the analysis and design of modeling e-learning metadata and elicit the design requirements, on the basis of the metadata standard KEM 3.0, about the elements that are expected to be needed in future e-learning systems. Based on the requirements from the analysis, we present the three-layer model for classifying the requirements by the importance of metadata elements per Kana Model. An intelligent e-learning system is to be developed based on the proposed modeling design, which we hope to influence the development of an international standard in the future.

• Management & Information Systems Review
• /
• v.4
• /
• pp.29-66
• /
• 2000

The current economic environmental changes such as globalization, information and opening of the market is calling for or needing the more rapid change of management and/or marketing strategies of the company than they did before to survive in tile borderless international competition. Under this situation, this study focuses on the correspondence strategies of Electronic Commerce which is one of the key elements to overcome or lead the above demands through seeking the problems of the current EC acception and application specially in Chollabuk Do province. For the above purpose, this study surveys the questionary with business firms of above area and figures out what is the correlation between business form and size and EC acception and application and what is the problems on it. And than provides several counter strategies which are following based on the survey to keep this area companies from out of business and lead the above economic environmental changes. To expand the adoption and application of EC to this area, firstly, top managers of the company must recognize the necessity and importance of EC compared with traditional commerce and change their perception and attitude concerning EC positively, and than try to accept it as soon as possible. Secondly, the company need the retained earning to invest to EC and educate their managers and employees with total participation. Thirdly, local government has to improve its attention to EC as a best way or opportunity to reduce and overcome the economical gap and development its economy because EC can remove the physical time or distance and space, scale and capital limitations. Finally, government has to expand and establish information infrastructure such as technical infrastructure(communication and security technology), Functional infrastructure like standard protocol, Organizational infrastructure(interchange agreement, relative law) and social infrastructure to improve efficient electronic transaction which can Increase the company' international compatitiveness under the current economy trend.

• Atmosphere
• /
• v.32 no.4
• /
• pp.323-340
• /
• 2022

We analyzed the high-resolution wind data of Aircraft-Based Observation from the Mode-Selective Enhanced Surveillance (Mode-S EHS) data in Korea. For assessment of its quality, the Mode-S wind data was compared with the ECMWF ReAnalysis 5 (ERA5) reanalysis and Aircraft Meteorological Data Relay (AMDAR) data for more than 3-months from 7 May 2021 to 24 August 2021 near Incheon International Airport, Korea. Considering that the AMDAR reports are not provided by all commercial aircraft, total number of the Mode-S derived wind data with a second sampling rate was about twice larger than that of available AMDAR wind data. After the quality control procedures by removing erroneous samples, it was found that the root mean square errors (RMSEs) of the Mode-S retrieved winds are similar to that from the AMDAR winds. In particular, between 550 and 650 hPa levels, RMSE of the Mode-S (AMDAR) zonal wind against ERA5 data was about 2.3 m s^-1 (1.9 m s^-1), and those increased to 3.3 m s^-1 (2.4 m s^-1) in 200~500 hPa levels. A similar trend was found in the meridional wind, but a distinct positive mean bias of 2.16 m s^-1 was observed between 875 and 1,000 hPa levels. Winds retrieved from the Mode-S also showed a good agreement directly with AMDAR data. As the Mode-S provides a large amount of data with a reliable quality, it can be useful for both data assimilation in the numerical weather prediction model and situational awareness of wind and turbulence for aviation safety in Korea.

• Economic and Environmental Geology
• /
• v.42 no.6
• /
• pp.645-654
• /
• 2009

Recently there have been increasing consumers' interests in the geographical origin of foods, due to the FTA (Free Trade Agreement) in the global market. Especially, in Korea, in relation to BSE (bovine spongiform encephalopathy), it is considered to be urgent to develop analytical techniques for distinguishing the geographical origin of beef. Korea is facing conclusion of FTA with many countries, and there is a deep national concern about the distinction of the geographical origin of food. Diverse analytical techniques have been used in many of recent researches to obtain data for distinguishing the geographical origin of foods produced in various countries. In this paper, we reviewed national and international researches about tracing of geographical origin and food authentication using stable isotopes. Improvement of the isotopic techniques and their numerous application have been provided useful information of their geographical origin in food products. Furthermore, we expect that this study could be detecting of many frauds and illegal transaction of food products. We look forward to active progressing research of detecting food origin using isotope analysis and numerous application about imported food products.