• Korean Journal of Ecology and Environment
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• v.46 no.4
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• pp.488-498
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• 2013

A three-dimensional hydrodynamic model was applied to the Lake Euiam. The lake has three inflows, of which Gongji Stream has the smallest flow rate and poorest water. The dam-storage volume, watershed area, lake shape and discharge type of the Chuncheon Dam and the Soyang Dam are different. Therefore, it is difficult to analyze the water plume and mixing pattern due to the difference of the two dams regarding the amount of outflow and water temperature. In this study, we analyzed the effects of different characteristics on temperature and conductivity using the model appropriate for the Lake Euiam. We selected an integrated system supporting 3-D time varying modeling (GEMSS) to represent large temporal and spatial variations in hydrodynamics and transport of the Lake Euiam. The model represents the water temperature and hydrodynamics in the lake reasonably well. We examined residence time and spreading patterns of the incoming flows in the lake based on the results of the validated model. The results of the water temperature and conductivity distribution indicated that characteristics of upstream dams greatly influence Lake Euiam. In this study, the three-dimensional time variable water quality model successfully simulated the temporal and spatial variations of the hydrodynamics in the Lake Euiam. The model may be used for efficient water quality management.

• Korean Chemical Engineering Research
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• v.58 no.2
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• pp.197-208
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• 2020

This study was carried out to analyze spatial and temporal incidence characteristics of scrub typhus and predict the future incidence of scrub typhus since the incidences of scrub typhus have been rapidly increased among vector-borne diseases. A maximum entropy (MaxEnt) ecological model was implemented to predict spatial distribution and incidence rate of scrub typhus using spatial data sets on environmental and social variables. Additionally, relationships between the incidence of scrub typhus and critical spatial data were analyzed. Elevation and temperature were analyzed as dominant spatial factors which influenced the growth environment of Leptotrombidium scutellare (L. scutellare) which is the primary vector of scrub typhus. A temporal number of diseases by scrub typhus was predicted by a deep neural network (DNN). The model considered the time-lagged effect of scrub typhus. The DNN-based prediction model showed that temperature, precipitation, and humidity in summer had significant influence factors on the activity of L. scutellare and the number of diseases at fall. Moreover, the DNN-based prediction model had superior performance compared to a conventional statistical prediction model. Finally, the spatial and temporal models were used under climate change scenario. The future characteristics of scrub typhus showed that the maximum incidence rate would increase by 8%, areas of the high potential of incidence rate would increase by 9%, and disease occurrence duration would expand by 2 months. The results would contribute to the disease management and prediction for the health of residents in terms of public health.

• Korean Journal of Agricultural and Forest Meteorology
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• v.10 no.4
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• pp.158-166
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• 2008

The pumpkin fruit fly, Bactrocera depressa (Tephritidae: Diptera), is one of the most important pests in Cucurbitaceae plants. This study was conducted to investigate the basic ecology of B. depressa, and to develop a forecasting model for predicting the time of adult emergence in early season. In green pumpkin producing farms, the oviposition punctures caused by the oviposition of B. depressa occurred first between mid- and late July, peaked in late August, and then decreased in mid-September followed by disappearance of the symptoms in late September, during which oviposition activity of B. depressa is considered active. In full-ripened pumpkin producing farms, damaged fruits abruptly increased from early Auguest, because the decay of pumpkins caused by larval development began from that time. B. depressa produced a mean oviposition puncture of 2.2 per fruit and total 28.8-29.8 eggs per fruit. Adult emergence from overwintering pupae, which was monitored using a ground emergence trap, was first observed between mid- and late May, and peaked during late May to early June. The development times from overwintering pupae to adult emergence decreased with increasing temperature: 59.0 days at $15^{\circ}C$, 39.3 days at $20^{\circ}C$, 25.8 days at$25^{\circ}C$ and 21.4 days at $30^{\circ}C$. The pupae did not develop to adult at $35^{\circ}C$. The lower developmental threshold temperature was calculated as $6.8^{\circ}C$ by linear regression. The thermal constant was 482.3 degree-days. The non-linear model of Gaussian equation well explained the relationship between the development rate and temperature. The Weibull function provided a good fit for the distribution of development times of overwintering pupae. The predicted date of 50% adult emergence by a degree-day model showed one day deviation from the observed actual date. Also, the output estimated by rate summation model, which was consisted of the developmental model and the Weibull function, well pursued the actual pattern of cumulative frequency curve of B. depressa adult emergence. Consequently, it is expected that the present results could be used to establish the management strategy of B. depressa.

• Health Policy and Management
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• v.28 no.3
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• pp.240-250
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• 2018

By the end of 2017, in a world of 7.6 billion people, there were inequalities in healthcare indices both within and between nations, and this gap continues to increase. Therefore, this study aims to understand the current status of regional inequalities in healthcare indices and to find an action plan to tackle regional health inequality through a geo-economic review in Korea. Since 2008, there was great inequality in life expectancy and healthy life expectancy by region in not only metropolitan cities but also districts in Korea. While the community health statistics from 2008-2017 show a continuous increase of inequality during the last 10 years in most healthcare indices related to noncommunicable diseases (except for some, like smoking), the inequality has doubled in 254 districts. Furthermore, health inequality intensified as the gap between urban (metropolitan cities) and rural regions (counties) for rates of obesity (self-reported), sufficient walking practices, and healthy lifestyle practices increased from twofold to fivefold. However, regionalism and uneven development are natural consequences of the spatial perspective caused by state-lead developmentalism as Korea has fixed the accumulation strategy as its model for growth with the background of export-led industrialization in the 1960s and heavy and chemical industrialization in the 1970s, although the Constitution of the Republic of Korea recognizes the legal value of balanced development within the regions by specifying "the balanced development of the state" or "ensuring the balanced development of all regions." In addition, the danger of a 30% decline or extinction of local government nationwide is expected by 2040 as we face not only a decline in general and ageing populations but also the era of the demographic cliff. Thus, the government should continuously operate the "Special Committee on Regional Balanced Development" with a government-wide effort until 2030 to prevent disparities in the health conditions of local residents, which is the responsibility of the nation in terms of strengthening governance. To address the regional inequalities of rural and urban regions, it is necessary to re-adjust the basic subsidy and cost-sharing rates with local governments of current national subsidies based mainly on population scale, financial independence of local government, or distribution of healthcare resources and healthcare indices (showing high inequalities) overall.

• Journal of KIISE:Information Networking
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• v.29 no.3
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• pp.253-264
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• 2002

Recently, hierarchical architectures of databases for location management have been proposed in order to accommodate the increase in user population in future personal communication systems. In particular, a 3-level hierarchical database architecture is compatible with current cellular mobile systems. In the architecture, a newly developed additional databases, regional location database(RLR), are positioned between HLR and VLRs. We propose an efficient cache scheme, called the Double T-thresholds Location Cache Scheme. The cache scheme extends the existing T-threshold location cache scheme which is competent only under 2-level architecture of location databases currently adopted by IS-41 and GSM. The idea behind our scheme is to use two pieces of cache information, VLR and RLR serving called portables. The two pieces are required in order to exploit root only locality of registration area(RA) but also locality of regional registration area(RRA) which is the wide area covered by RLR. We also use two threshold values in order to determine whether the two pieces are obsolete. In order to model the RRA residence time, the branching Eralng-$\infty$ distribution is introduced. Our minute cost analysis shows that the double T-threshold location cache scheme yields significant reduction of network and database costs for molt patterns of portables.

• Health Policy and Management
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• v.21 no.2
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• pp.329-348
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• 2011

This research analyzed 168,010 cases of death of the aged over 65 from 244,867cases of death excluding 7 unknown age cases from 244,874 all age cases of death by using the death data of the National Statistical Office for 2007 to figure out factors affecting the quality of causes of death statistics of the aged and to suggest the ways of improving the quality of death statistics of the aged in korea. This research tried to derive factors affecting ill-defined cause of death category in acordance with WHO's guidelines and to find causes of lowering the accuracy of causes of death statistics of the aged. This research identified the problems of causes of death statistics of the aged by using both demographic characteristics such as sex, age, marital status, educational attainment, residential region, region size and factors of death items as independent variable to find causes of ill-defined cause of death of the aged. Logistic regression analysis was executed to calculate the hazard ratio about the ill-defined causes of death of the aged and multiple regression analysis was conducted to derive factors affecting the ill-defined cause of death by regional groups through using these independent variables such as the component ratio of over age 65, female death rates, doctors insitutions rate, medical institutions rate, attaching rates of death certificate by neighborhood. As a results of this research, R-code was the highest of ill-defined causes of death, accounting for 82.1%, and senility death(R54) of R-code was the highest, accounting for 91.2%. through subdivided order distribution of the ill-defined causes of death of the aged. As ill-defined causes of death by regional groups, attaching rates of death certificate by neighborhood was the most important factor(p<0.05) and also showed regression model's description with 83.8% ($R^2$=83.8%). Furthermore, Jeon-nam was the highest in the regional groups and these regions such as Je-ju, Jeon-buk, Chung-nam were not only attaching the death certificate by neighborhood but also were high at the rate of ill-defined causes of death. Therefore, this research found that both reconsideration about death certificate by neighborhood and education for doctors who write death certificate were needed the most.

• Management & Information Systems Review
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• v.37 no.3
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• pp.65-81
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• 2018

This study estimated the long-run and the short-run price and income elasticity of crude oil demand by using the ARDL model in Korea. First, the long-run cointegration relationship existed between crude oil demand and price or income in the ARDL-bounds tests. Second, the long-run own price, the cross price elasticity and the income elasticity were both statistically significant elastic and sensitive in the ARDL. Third, there was autocorrelation of the residuals, but no misspecification errors and heteroscedasticity, and then the residuals showed a normal distribution. And the CUSUM & CUSUMSQ tests showed that the coefficients were stable. Fourth, the short-run own price, the cross price elasticity and the income elasticity were both statistically significant elastic and sensitive in the ARDL-RECM. The ECM with the short-run dynamics showed rapid adjustments in the long-run equilibrium of oil demand after the economic crisis. In the short-run, the sensitivity of crude oil demand to price and income changes has moved in the same direction as the long-run case. Korea, depending too much on foreign crude oil, is vulnerable to the shocks of oil prices, so rising oil prices can certainly have a negative impact on Korea's trade balance. And the elasticity of long-run oil prices may help to control and manage Korea's oil demand. The government needs to strengthen monitoring of the country's policies and market trends related to crude oil, establish strategies to customize national policies and market conditions, and strengthen active market dominance efforts through pioneering new market and diversification.

• Journal of Korea Water Resources Association
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• v.49 no.9
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• pp.761-771
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• 2016

The GloSea5 (Global Seasonal forecasting system version 5) is provided and operated by the KMA (Korea Meteorological Administration). GloSea5 provides Forecast (FCST) and Hindcast (HCST) data and its horizontal resolution is about 60km ($0.83^{\circ}{\times}0.56^{\circ}$) in the mid-latitudes. In order to use this data in watershed-scale water management, GloSea5 needs spatial-temporal downscaling. As such, statistical downscaling was used to correct for systematic biases of variables and to improve data reliability. HCST data is provided in ensemble format, and the highest statistical correlation ($R^2=0.60$, RMSE = 88.92, NSE = 0.57) of ensemble precipitation was reported for the Yongdam Dam watershed on the #6 grid. Additionally, the original GloSea5 (600.1 mm) showed the greatest difference (-26.5%) compared to observations (816.1 mm) during the summer flood season. However, downscaled GloSea5 was shown to have only a -3.1% error rate. Most of the underestimated results corresponded to precipitation levels during the flood season and the downscaled GloSea5 showed important results of restoration in precipitation levels. Per the analysis results of spatial autocorrelation using seasonal Moran's I, the spatial distribution was shown to be statistically significant. These results can improve the uncertainty of original GloSea5 and substantiate its spatial-temporal accuracy and validity. The spatial-temporal reproducibility assessment will play a very important role as basic data for watershed-scale water management.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.8
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• pp.181-189
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• 2017

This study examines whether the variables used in the Unified Theory of Acceptance and Use of Technology(performance expectancy, effort expectancy, social influence, and facilitating conditions) is applicable to continuous usage of uTradeHub at a time of expansion in the use of uTradeHub. In addition, the role of user satisfaction(mediating effect) and CEO support(interaction effect) in the relationship is identified attempting to provide basic data to help uTradeHub management strategy establishment. A total of 101 valid responses collected through questionnaires were used for empirical analysis(using SPSS 24.0), and the results are as follows. First, for the effect of the integration technology acceptance factor on user satisfaction(H1), only performance expectancy, effort expectancy, and social influence were significant, but facilitating conditions was not significant. Second, for the effect of user satisfaction on the continued use of uTradeHub(H2), there was a significant result. Third, the mediation effect on verification of user satisfaction(H3) was full where performance expectancy, effort expectancy, and social influence prompted continuous usage through user satisfaction. Fourth, for interactive effect verification of CEO support(H4), an interaction effect was shown only in the influence relationship of performance expectancy and social influence on user satisfaction.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.21 no.6
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• pp.95-113
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• 2018

We studied the change of wetland vegetation structure to understand ecological restoration process of wetlands through the field survey of ecological restoration projects in Incheon, Iksan and Busan. We compared the vegetation plan at the time of planted with the results of the vegetation monitoring in 2018, and analyzed the changes in wetland vegetation structure. Based on results, we attempted to understand the restoration process of those wetlands and discuss the management measures for sustainable wetland restoration. As a result, in the Incheon Yeonhee restoration wetland, the number of plant species was increased, from 18 species in 2016 to 29 in 2018. The dominant species, Myriophyllum verticillatum, covered the wetland most and its occupied area was increased. On the other hand, the distribution area of the planted emergent hydrophytes was reduced. The area of open water decreased from 71.7% in 2016 to 48.8% in 2018. In Busan Igidae restoration wetland, the number of plant species was increased, from 6 species in 2014 to 31 in 2018. The dominant species was Myriophyllum verticillatum and its occupied area was increased. The area of floating plant communities that planned has decreased. The open water area decreased from 83.9% in 2014 to 31.8% in 2018. In Iksan Sorasan restoration wetland, the number of plant species was increased, from 13 species in 2016 to 36 in 2018. The dominant species was Phragmites communis Trin. and its occupied area was increased. The other planted species showed a tendency to be decreased by Phragmites communis Trin. and its terrestrialization. The open water area decreased from 86.6% in 2016 to 6.7% in 2018. These results suggest that wetlands should be managed by considering the change of vegetation structure and open water areas based on the following succession process, because it affects the habitat suitability of wetland organisms and biodiversity as well. Thus, the continuous monitoring for the ecological structure of restored wetland is important, and it could be possible step to develop sustainable wetland ecological restoration model.