• Proceedings of the Korea Air Pollution Research Association Conference
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• 2002.11a
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• pp.429-429
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• 2002

This study examines the influence of long-range transport of dust particles and air pollutants on photochemistry of OH and NO$_3$ at Jeju Island (33.17$^{\circ}$ N, 126.10$^{\circ}$ E) during the Asian dust-storm (ADS) period in April 2001. The atmospheric concentrations of criteria pollutants (O$_3$, NO$_2$, CO) and sulfur species were measured at a ground station on Jeju Island, Korea as part of the ACE-Asia intensive operation. Three ADS events were observed during the periods of 10-12, 13-14, and 25-26 April, respectively. The concentrations of the criteria pollutants (i.e., $O_3$, NO$_2$, and SO$_2$) were not significantly different from those during the non-Asian-dust-storm (NADS) period. Average OH and NO$_3$ levels at Jeju Island during the study period (ADS and NADS) were estimated to be 4-10 $\times$ 10$^{5}$ moleculescm$^{-3}$ and 2-4 pptv, respectively. Two main sources of OH radical were the primary production from the reaction of water vapor ($H_2O$) and O(1D) radicals and the reaction of HO$_2$ with NO. CO was a dominant sink of OH during the ADS period: whereas NO$_2$ was the most important during the NADS period. for NO$_3$ radical, a reaction of NO$_2$ with $O_3$ was the most important atmospheric source; while $N_2$O$_{5}$ uptake on dust particles was the most dominant sink during the ADS period.

• Journal of Korea Water Resources Association
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• v.37 no.7
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• pp.553-567
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• 2004

This study proposes a modified standardized precipitation index (MSPI) which was developed to make up for the weakness of the SPI. Both MSPI and SPI are applied to the monthly rainfall at the Seoul station for the drought analysis. The MSPI proposed is nothing but the SPI for the normalized monthly rainfall, that is, an extra step for normalizing the monthly rainfall is included before driving the SPI. Thus, the MSPI has a structure to transfer the relative amount of rainfall to the next months, but the SPI the absolute amount of rainfall. The monthly rainfall data at the Seoul station used in this study are those collected from 1777 to 1996. The rainfall data collected before and after the long dry period around 1900 were also analyzed separately for the comparison. The results derived are as follows. (1) The MSPI was found to be more practical compared to the SPI. This was assured by comparing the analysis results of the data including and excluding the long dry period around 1900. (2) The MSPI is found to be less sensitive than the SPI to the extreme rainfall events. For the MSPI, the occurrence probabilities of moderate drought before and after the long dry period are similar, but those for the extreme drought becomes slightly decreased after the long dry period (from about 18 years of return period before the long dry period to the 16 years after the long dry period). However, the duration becomes longer after the long dry period (the duration for the extreme drought has been increased from 2 to 2.5 months after the long dry period). This results can also be compared with a rather unreasonable result derived by applying the SPI (for the extreme drought the return period has been decreased to be from 25 to 10 years after the long dry period, on the other hand the duration has been increased from 1.5 months to 3.5 months). So, we man conclude that the MSPI is more practical for the drought analysis that the SPI.

• Journal of the Korean Society of Food Science and Nutrition
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• v.18 no.4
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• pp.375-388
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• 1989

The study was designed to examine the of effects of level of protein intake on Cu metabolism in 6 healthy young adult women. The subjects were given 4 levels of protein diet, 0.45g (period I), 0.60g (period III), 0.75g (period II) and 0.90g (period IV) of protein per Kg of body weight and 0.86mg 0.70mg, 1.86mg and 2.34mg of Cu per day for 5 days respectively. During the experimental period, urine sample were collected everyday and fecal sample were collected for last 2 days of each dietary period. The samples were analyzed for Cu contents. Mean daily urinary Cu excretion were $0.12{\pm}0.03mg$ for period I, $0.16{\pm}0.02mg$ for period III, $0.35{\pm}0.08mg$ for period II and $0.11{\pm}0.02mg$ for period IV, and the mean daily urinary excretion of Cu was not affected significant difference by the level of protein intake. Mean daily fecal Cu excretion were $0.12{\pm}0.03mg$ for period I, $0.16{\pm}0.02mg$ for period III, $0.35{\pm}0.08mg$ for period II and $0.11{\pm}0.02mg$ for period IV, and the mean daily urinary excretion of Cu was not affected significant difference by the level of protein intake. Mean dailey Mean dailey fecal Cu excretion were $1.23{\pm}0.16mg$ for period I, $1.28{\pm}0.25mg$ for period III, $0.99{\pm}0.01mg$ for period II and $1.85{\pm}0.19mg$ for period IV, and the difference of the 2 periods I vs IV was significant(p<0.05). Mean dailey cu balance were $0.48{\pm}0.14mg$ for period I, $0.74{\pm}0.26mg$ for period III, $0.52{\pm}0.12mg$ for period II and $0.38{\pm}0.20mg$ for period IV, and the difference of the 2 periods I vs IV was significant(p<0.05).

• Economic and Environmental Geology
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• v.52 no.4
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• pp.299-312
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• 2019

This study analyzed variation of tidal channels associated with Shihwa reclamation project for corresponding observation period based on remote sensing approaches. The project period was subdivided to developing period, closed period, and open period based on developing and management plan of Shiwa lake, and number, length, width, and direction of tidal channels for each period were analyzed using CORONA, Landsat 5 TM, Landsat 7 ETM+, and orthorectified aerial photographs. Number of tidal channels decreased from developing to opening period while $3^{rd}$ order channles did not show noticeable changes. The length of tidal channels decreased during developing to closed period, and increasing trend of $2^{nd}$ and $3^{rd}$ order channels was observed for the opening period. The average widtrh of $2^{nd}$ and $3^{rd}$ order channels decreased from developing to closed period, and increased during open period. The direction of tidal channels showed NW and NE direction in general, while the rose diagram showed deacrased frequency of NE direction and increased frequency of NW direction during the open period. These variations in tidal channels are considered to be related to changes in tidal energy environment, where stable energy environment before the project was changed to disconnection of tidal energy by closed environment, and re-connection of the energy during the open period.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.260-260
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• 2011

SWAT is semi-distributed and continuous-time distributed simulation watershed model, which can simulate point and nonpoint source pollutants as well as hydrology and water quality. It was developed to predict the effects of alternative management decisions on water, sediment, and chemical yields with reasonable accuracy. It is able to predict and manage hydrology, sediments, nutrients, and pesticides with Best Management Practices (BMPs) in a watershed. SWAT model also has potential for use in ungauged basins to predict streamflow and baseflow from saturated source area in watersheds. According to various cultivation practices and climate change, SWAT model is available to analyze relative change in hydrology and water quality. In order to establish optimum management of water quality, both monitering and modeling have been conducted actively using SWAT model. As SWAT model is computer program to simulate a lot of natural phenomena, it has limitation to predict and reflect them with on hundred percent accuracy. Thus, it is possible to analyze the effect of BMPs in the watershed where users want to simulate hydrology and water quality only if model accuracy and applicability are assessed first of all and the result of it is well for the study watershed. For assessment of SWAT applicability, most researchers have used $R^2$ and Nash and Sutcliffe Efficiency (NSE). $R^2$ and NSE are likely to show different results according to a warm up period and sometimes its results are very different. There have been hardly any studies of whether warm up period can affect simulation results in SWAT model. In this study, how warm up period has a effect on SWAT results was analyzed and a appropriate warm up period was suggested. Lots of SWAT results were compared after using measured data of Soyanggang-dam watershed and applying various warm up period (0 ~ 10 year(s)). As a result of this study, when there was no warm up period, $R^2$ and NSE were 0.645, 0.602 respectively, when warm up period was 2 years, $R^2$ and NSE were 0.648, 0.632, and when warm up period was 4 years, $R^2$ and NSE were 0.663, 0.652 separately. Through this study, sensitive analysis of warm up period in SWAT model was conducted, and this study could give a guideline able to simulate hydrology and water quality for more accuracy than before as users change a lot of warm up periods as well as any simulation parameters.

• Journal of Bio-Environment Control
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• v.12 no.1
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• pp.1-6
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• 2003

This study was conducted under the condition of greenhouse to investigate the relationships between the period of long day (LD) treatment before short day treatment, the dry matter production and flower quality of cut chrysanthemum (Indicum group) cv. Reagan Improved at Wagenigen University in the Netherlands. Rooted cuttings of chrysanthemum (Indicum group) cv. Reagan Improved were transplanted on 6th, 13th, loth of September and all of them were treated with short-days (SD) on 21th September. The periods from planting until final harvest were 70, 77, 84 days after being planted for 1, 2, and 3 week-LD period, respectively. The time of flower initiation was similar in all treatments. The number of flowers per plant was greater in the plot of 3 week-LD period than that in the plot of 1 or 2 week-LD period. The fresh weight and dry weight of flowers also increased more in the plot of 3 week-LD period than that in the 1 week-LD period by 4g and 0.4g, respectively. The final dry matter production ($g{\cdot}m$^{-2}$ ) was greater in the treatment of 3 week-LD period than 1 or 2week-LD period. In this study, LD period before short day treatment did not affect the time of flower initiation and flower quality. As a result, 3 week-LD period before short day treatment was strongly recommanded for producing high quality cut flowers of greenhouse-grown chrysanthemum.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.6
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• pp.1421-1424
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• 2006

By extending the Mandelbrot set for the complex polynomial $$M={c\in C\;:\; _{k\rightarrow\infty}^{lim}P_c^k(0)\;{\neq}\;{\infty}$$ we define the degree-n bifurcation set. In this paper, we formulate the boundary equation of a period-2 component on the main component in the degree-9 bifurcation set by parameterizing its image. We establish an algorithm constructing a period-2 component in the degree-9 bifurcation set and the typical implementations show the satisfactory result with Mathematica codes grounded on the analysis.

• English Language & Literature Teaching
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• v.16 no.4
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• pp.107-131
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• 2010

The goals of the present study are two-fold: 1) to examine NNS teachers' needs for training period in improving their general communicative competence and classroom communicative competence, and 2) to explore the relationships of teachers' needs for the training period, and their current levels of general/classroom communicative competence and other background variables. Data was collected from seventy primary and secondary school English teachers (N=70) who participated in the six-month intensive teacher training program in South Korea. The teacher trainees responded to four questionnaires of 1) the self-diagnosis of their current levels of four language skills (L/S/R/W) in both general/classroom communicative competence, 2) the training period required to improve their general/classroom communicative competence for teaching both English and other subjects through English, 3) the period of their English teaching, and 4) the proportion of their English use in class. The data analysis has shown that there were the strong relationships between trainee needs for the training period and their teaching period, and the proportion of their English use in class. In terms of trainees' communicative competence, the significant relations of both their general/classroom communicative competence and their needs for the training period were found. Implications of the findings are discussed.

• Journal of the Society of Naval Architects of Korea
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• v.52 no.2
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• pp.135-142
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• 2015

The Anti-Rolling Tank(ART) has an advantage over the other roll stabilizing devices, when ship is staying and working at one site of sea. An important design point of ART is the tank tuning, that is, matching the tank natural period to the ship's roll natural period. Since the load condition and consequently the roll natural period of ship is to be changed widely, the natural period of ART also has to be changed widely. In case of the existing U-tube type ART with a single layer duct, the tank natural period can be changed in a relatively narrow range. This paper suggests a new U-tube type ART system using a double layer duct to enable wide change of ART natural period. Through the roll experiments performed in regular beam waves for a box-type model ship, it is shown that the double layer duct ART has about two times wider period range and a better reducing effect of roll magnitude than the single layer duct ART.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.31 no.2
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• pp.137-142
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• 2005

To analyze the developmental changes in soma diameters of digastric motoneurons, wheat-germ agglutinin conjugated horseradish peroxidase (WGA-HRP) was injected into the digastric muscle and visualized the retrogradely HRP-labeled motoneurons through tungstate/tetramethylbenzidine (TMB) and following diaminobenzidine (DAB) reactions. The results obtained from Sprague-Dawley rats at postnatal days 1 (P1), 10 (P10) and 30 (P30) indicated as follows: firstly, soma diameters of digastric motoneurons showed unimodal distribution in all postnatal days examined; secondly, the period of P1 to P10 (period 1) showed about 2 times faster growth rate than that of P10 to P30 (period 2); thirdly, the smallest soma examined in each postnatal day exhibited slower growth rate with that of the largest one (increase ratio in soma diameters from P1 to P30, smallest vs. largest = 1.62 : 1.93); Finally, relative growth rates a day showed again that period 1 had faster growth rate than that of period 2. Consequently, developmental changes in soma diameters of digastric motoneurons resulted in very different growth rates between both periods. This implies that the growth of the soma is almost completing within P10 and thereafter growing slowly. The period 1 and 2 are corresponding to sucking and sucking/masticatory period, respectively. Therefore present study providing morphological changes in soma diameters of digastric motoneurons suggests that both periods and their different growth rates of the motoneurons in each period may closely be related with each other.