• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.8
• /
• pp.3726-3734
• /
• 2012

This study evaluated the behavior of pollutants based on the seasonal change by selecting the branch river's factors that influence the outflow of pollutants in Soyang lake basin. The analysis method was the factor analysis that classified the factors of the drainage area influencing the outflow of pollutants, and evaluated selected representative factors. As a result of the study, SS and T-P factors should be classified as similar factors to the storm water runoff, and the improvement of water must be strived through managing source of pollution at the time of no rain. Second, as the result of the influence from the factors, spring and winter seasons usually exert 36% influence and summer and fall exert over 90% significant influence that the improvement of water through managing source of water seems possible. At last, the prediction about delivery pollution load considering the outflow characteristic of pollutants at the drainage area based on seasonal change by regarding selected factors as independent variables is possible.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.31 no.4
• /
• pp.535-544
• /
• 1998

Seasonal variation of the crab community in the eelgrass (Zostera marina) bed in Kwangyang Bay was studied based on the monthly collections through a year of 1994. The crab community in the eelgrass bed was composed of 21 species representing 12 families. The community was dominated by Charybdis Japonica, Telmessus acutidens, Hemigrapsus penicillatus, and Pugettia quadridens. Crabs collected in the study area were primarily small-sized species or early juveniles of large crab species. Most individuals had carapace width smaller than 25 mm except C. japonica and T. acutidens which had maximum carapace width over 85 mm. More than 5 species were collected every month except January and February (4 and 3 species, respectively). The peak abundance occurred in August and low abundances in autumn and winter. Species diversity indices showed that more diverse crabs were collected In spring and summer, and lesser ones in autumn and winter. The crabs in the study area can be grouped into three groups on the basis of their occurrence patterns: resident species, seasonal species, and temporary species. More abundant and more diverse crabs were collected during nighttime than daytime.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.26 no.1
• /
• pp.58-63
• /
• 2022

The daily number of confirmed cases of Coronavirus disease 2019(COVID-19) ranges between 1,000 and 2,000. Despite higher vaccination rates, the number of confirmed cases continues to increase. The Mu variant of COVID-19 reported in some countries by WHO has been identified in Korea. In this study, we predicted the number of confirmed COVID-19 cases in Korea using the SARIMA for the Covid-19 prevention strategy. Trends and seasonality were observed in the data, and the ADF Test and KPSS Test was used accordingly. Order determination of the SARIMA(p,d,q)(P, D, Q, S) model helped in extracting the values of p, d, q, P, D, and Q parameters. After deducing the p and q parameters using ACF and PACF, the data were transformed and schematized into stationary forms through difference, log transformation, and seasonality removal. If seasonality appears, first determine S, then SARIMA P, D, Q, and finally determine ARIMA p, d, q using ACF and PACF for the order excluding seasonality.

• Environmental and Resource Economics Review
• /
• v.31 no.3
• /
• pp.343-365
• /
• 2022

This paper tries to identify the effect of reducing PM2.5 concentration of the First Seasonal Management Policy implemented by Korean government by using statistical method. In particular, this paper tests the hypothesis that this policy effect may differ by region (west-coast, south-coast, and east-coast). To this end, this paper analyzed only pure policy effects by removing temporal abnormalities such as COVID-19, warm winter temperature during the policy implementation period (December 2019 to March 2020) by using the difference-in-difference method (DID). As a result of the analysis, this policy had the effect of reducing PM2.5, but the effect is not homogenous by region. In particular, PM2.5 reducing effect is the largest in west-coast region and south-coast region folllows, but its effect is not statistically significant in the east-cost region. In conclusion, this paper drew implications that the current Seasonal mamangement policy which is implemented regardless of the regional difference needs to be changed.

• Journal of Korea Port Economic Association
• /
• v.31 no.1
• /
• pp.69-84
• /
• 2015

The purpose of this study is to forecast the seaborne trade volume during January 1994 to December 2014 using the multiplicative seasonal autoregressive integrated moving average (ARIMA) along with intervention factors and an artificial neural network (ANN) model. Diagnostic checks of the ARIMA model were conducted using the Ljung-Box Q and Jarque-Bera statistics. All types of ARIMA process satisfied the basic assumption of residuals. The ARIMA(2,1,0) $(1,0,1)_{12}$ model showed the lowest forecast error. In addition, the prediction error of the artificial neural network indicated a level of 5.9% on hidden layer 5, which suggests a relatively accurate forecasts. Furthermore, the ex-ante predicted values based on the ARIMA model and ANN model are presented. The result shows that the seaborne trade volume increases very slowly.

• Journal of Soil and Groundwater Environment
• /
• v.8 no.1
• /
• pp.68-74
• /
• 2003

SHARP numerical model was used to estimate the interface, ranges and seasonal variations of seawater intrusion. The interface obtained from the SHARP model represented more sensitive to seasonal variations than that estimated from the monitoring wells. When TDS and groundwater velocity vector distributions generated by SUTRA simulations are compared to the interfaces obtained from SHARP simulation, the difference of the range on seawater intrusion is less than 50 m, and the range of seawater intrusion from seasonal variations has the difference of about 12 m. These differences are small for the numerical simulation of the coastal aquifer at regional scale. Therefore, the model with sharp interface is very useful to estimate the interface at this study site, where is regional aquifer system in the scale of seawater infusion. However the SHARP model have some limitations in simulating the range of seawater intrusion, when the hydrodynamic dispersion is significant for seawater intrusion at local aquifer system.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.29 no.4
• /
• pp.691-700
• /
• 2000

The purpose of this study was to estimate food intakes of the long-lived elderly and to obtain the data for establishing dietary guidelines that may be recommended for the general population for the sake of longvity. The subjects of the study were 224 elderly people of age over 85 years living in Kyungpook Sung-Ju area who have no problem in daily living. The food consumption survey was carried out seasonally by the repeated 24-hr recall method for one year. The subject group for this study was composed of 58 males and 166 females, the average age being 87 years old. Food intakes of the winter were more than any other seasons. The mean daily total food intake per capita was 594.4g, 513.5 g (86.4%) from plant foods and 79.3 g(13.3%) from animal foods. The sequence of high intakes of food groups were cereals, vegetables, fruits, fishes, legumes and meats. Boiled white rice, beef soup, soybean paste soup, soybean paste stew, broiled yellow croaker, kimchi, ra myon and broiled noodles were consumed most frequently. In conclusion, the subjects consumed much more plants foods than animal foods and consumed more natural and seasonal foods than processed foods and also showed food habits of eating small meals. Dietary habits of eating small meals containing abundant amount of fresh plant foods might partially contribute to the longevity of the subjects.

• Journal of the Korean Society of Earth Science Education
• /
• v.13 no.1
• /
• pp.74-89
• /
• 2020

The purpose of this study was to develop a concept test tool for seasonal change with reliability and validity, and to objectively observe and analyze sub-concepts and misconceptions related to the concept of seasonal change to explain the relationship between variables. The development process of the conceptual change concept inspection tool consisted of the development of the inspection tool development plan, the development of the inspection tool draft, the modification of the preliminary inspection and inspection tools, the development of the final inspection tool, and the implementation of this inspection. The developed test tool can be used to provide students with appropriate learning and help by examining students' degree of seasonal change concept formation and analyzing the cause of the difficulty in concept formation. As a result of regression analysis of 198 students in 6th grade using the developed test tool, it was found that the understanding of pre-learning concept and correction of misconception had a statistically significant effect on the concept learned in the seasonal change unit, and misconception had greater effect. Correction of misconceptions had a significant effect on students above the average score among the two sections created and cut based on the average score, and on the students below the average score, the understanding of pre-learning concept had a significant effect.

• Journal of the Korean earth science society
• /
• v.31 no.4
• /
• pp.335-347
• /
• 2010

The statistical characteristics of Cloud-to-Ground (CG) lightning data, observed by the total lightning detection system (TLDS) of KMA during the recent seven years (2002-2008), have been analyzed. Lightning frequency shows a strong interannual, seasonal and diurnal variations without regard to the polarity. The 74% and 0.6% of the total lightning occurred during the summer and winter, respectively. And it has a bimodal diurnal variation with two peaks (dawn: 0500-0700 LST, mid-afternoon: 1500-1600 LST). The ratio of positive flashes to negative ones also has a strong seasonal variation with the maximum and minimum during winter (62.5%) and summer (7.3%), respectively. Unlike the lightning frequency, the lightning intensity of negative flashes shows a weak interannual, seasonal and diurnal variations. However, the lightning intensity of positive flashes exhibits an inverse seasonal variation to that of lightning frequency, with the minimum and maximum during summer and winter, respectively. The lightning density is greatly higher in the western inland areas and the West/South Sea than in the eastern part and the East Sea. In general, the lightning intensity is stronger in the ocean, especially in the East Sea than in the inland area, regardless of the polarity.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.16 no.3
• /
• pp.213-218
• /
• 2014

Effects of elevated $CO_2$ on leaf phenology of Quercus acutissima were examined using open-top chambers, which had ambient and elevated $CO_2$ concentrations (ambient ${\times}1.4$, ambient ${\times}1.8$). To analyze the effect of chamber, non-treatment block was established near outside of the chambers. In 2013, budburst, leaf unfolding, coloring, and shedding were surveyed, and spring phenology was surveyed in 2014. Thermal sum (base temperature $+5^{\circ}C$) of each phenological event occurred was recorded. In addition, bud samples were collected and analyzed for carbohydrate contents in March 2014. Elevated $CO_2$ concentration advanced budburst and leaf unfolding, and delayed shedding in 2013. However, in 2014, the temperature of the spring season was high, and there was no significant effect of elevated $CO_2$ concentration on spring phenology. Carbohydrates content, such as starch, total non-structural carbohydrate and total soluble sugar, were significantly increased in response to elevated $CO_2$ concentration. It has been proposed that elevated $CO_2$ concentration could extend the growing season of temperate species with increased possibility of frost damage due to early bud opening and leaf unfolding. However, our analysis showed that the increased carbohydrate concentration in bud under elevated $CO_2$ would reduce the possibility of early spring frost damage by acting as cryoprotectant.