• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.39 no.1
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• pp.44-49
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• 2003

Masan Bay is one of the most heavily polluted bay in Korea owing to the large industrial complex and urban area. Water transparency, Secchi depth in meter, was observed 33 times totally at four sites during 1995 through 2002 and analysed statistically. The range was 0.2∼7.2m, mean 204m, and variation coefficient 60% in totally. Roughly speaking, monthly mean showed lower value April or July than other months. Seasonal mean showed lower in spring or summer than other seasons. Yearly mean was lowest in '95 and '98 during 7 years. Each sampling site showed a different patterns by the monthly, seasonal or yearly transparencies. Inner bay area, S1 site, showed lowest transparency and highest variation coefficient owing to the streamlets and urban area. And it was supposed that one of the important factor affecting different transparency distribution of most seaward site, S4 site, among four sites in the Masan Bay may be the underwater effluents of urban sewage water treated.

• Journal of Korea Water Resources Association
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• v.48 no.6
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• pp.425-438
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• 2015

The objective of this study was to evaluate simulation of agricultural water supply considering yearly variation of irrigation efficiency. The water supply data of the Idong reservoir from 2001 through 2009 was collected and used for this study. Total 6 parameters including irrigation efficiency (Es), drainage outlet height, and infiltration, were used for sensitivity analysis, calibration, and validation. Among the parameters, the Es appeared to be the most sensitivity parameter. The Es was calibrated on a yearly basis considering sensitivity and time-varying characteristic, while other parameters were set to fixed values. The statistics of percent bias (PBLAS), Nash-Sutcliffe efficiency (NSE), and root means square error to the standard deviation of measured data (RSR) for a monthly step were 2.7%, 0.93, and 0.26 for the calibration, and 3.9%, 0.89, and 0.32 for the validation, correspondently. The results showed a good agreement with the observations. This implies that the modeling only with appropriate parameter values, apart from modeling approaches, can simulate the real supply operation reasonably well. However, the simulations with uncalibrated parameters from previous studies produced poor results. Thus, it is important to use calibrated values, and especially, we suggest the Es's yearly calibration for simulating agricultural water supply.

• The Korean Journal of Zoology
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• v.8 no.2
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• pp.51-54
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• 1965

Present author observed the variation in color and pattern and also those of geographical distribution of Graphosoma rubrolineatum WESTWOOD.And the variations were also studied in relation to the temperature and the humidity . The results are as follows . 1. The variations in color and pattern of G.rubrolineatum were gradually changed into black ones, and so they showed polymorphic. 2. Their colors and patterns were not variated in inland at all, while those variations in island increased according to the distance from the inland. 3. The red color of the patterns appeared the yellowish-red in inland, the blackish -red in island. 4. The variation in color and pattern of G.rubrolineatum occure in the region of the temperature below 22.8$^{\circ}C$ (mean temperaturrre of June, July and August)and the humidity above 72%(yearly average).

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.2
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• pp.142-149
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• 1995

This study was conducted to investigate the relationships between yearly variation of climatic components and yearly variations of productivity in monoculture cotton. In addition, correlation coefficients among yield and yield components were estimated. The data of yield and yield components from the four varieties(Kinggus, Yongdang local. 113-4, 380) were collected from 1978 to 1992 in Mokpo area. The meteorological data gathered at the Mokpo Weather Station for the same period were used to find out the relationships between climatic components and productivity. Yearly variation of the amount of precipitation and number of stormy days in July are large with coefficients of the variations(C.V)84.89 and 97.05%, respectively, while yearly variation, of the average temperature, maximum temperature, minimum temperature from May to Sep. are relatively small. Seed cotton yield before frost in Sep. and Oct. very greatly with C.V. of 68.77, 78.52%, respectively. Number of boll bearing branches and lint percentage show more or less small in C.V. with 11.77 and 19.13%, respectively and flowering date and boll opening date show still less variation. Correlation coefficients between precipitation in May and number of boll bearing branches, duration of sunshine in July and number of bolls per plant, maximum temperature in July and total seed cotton before the frost in Sep., Oct., and Nov. evaporation in Aug. are positively sig-nificant at the 1% level. There are highly significantly positive correlated relationships among yield(total seed cotton) and yield components. Total seed cotton yield(Y) can be predicted by multiple regression equation with independent variables of climatic factors in July such as monthly averages of average temperature($X_1$), maximum temperature($X_2$) and minimum temperature($X_3$), monthly amount of precipitation ($X_4$), evaporation($X_5$), monthly average of relative humidity($X_6$), monthly hours with sunshine($X_7$) and number of rainy days($X_8$). The equation is estimatedas Y =-1080.8515 + 144.7133$X_1$+15.8722$X_2$ + 164.9367$X_3$ + 0.0802$X_4$ + 0.5932$X_5$ + 11.3373$X_6$ + 3.4683$X_7$- 9.0846$X_8$. Also, total seed cotton yield(Y) can be predicted by the same method with climatic components in Aug., Y =2835.2497 + 57.9134$X_1$ - 46.9055$X_2$ - 41.5886X$_3$ + 1.2559$X_5$ - 21.9687$X_6$ - 3.3763$X_7$- 4.1080$X_8$- 17.5586$X_9$. And the error between observed and theoretical yield were less with approached linear regression.

• Proceedings of the Korean Society of Crop Science Conference
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• 2000.04a
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• pp.90-91
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• 2000

• Korean Journal of Fisheries and Aquatic Sciences
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• v.41 no.2
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• pp.134-139
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• 2008

To improve the oxygen-deficient water mass (ODW), the spatial and temporal variation in the water quality and characteristic of ODW occurrence were analyzed using yearly water quality data from 1989 to 2006 in Jinhae Bay, Korea. In addition, we estimated $ODW_{area},\;ODW_{vol.}$ and $ODW_R$ for Jinhae Bay. The overall water quality improved during the 2000s, based the annual variation in dissolved oxygen, chemical oxygen demand, etc. A cluster analysis classified Jinhae Bay into the southwestern, central, northern, and eastern regions. ODW occurred throughout the southwestern region in 1993 and 2002-2004, and the estimated $ODW_{vol.}$ was about $1.92km^3$. ODW did not occur in the eastern region because circulating seawater was exchanged in that part of Jinhae Bay. As ODW was generated every year in the southwestern region, this is the most polluted area in Jinhae Bay. The ODWR decreased in the northern region, showing that the water quality there has improved since a wastewater treatment plant began operating in 1994.

• Journal of Astronomy and Space Sciences
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• v.29 no.2
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• pp.97-101
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• 2012

Monitoring sunspots consistently is the most basic step required to study various aspects of solar activity. To achieve this goal, the observers must regularly calculate their own correction factor $k$ and keep it stable. Relatively recently, two observing teams in South Korea have presented interesting papers which claim that revisions that take the yearly-basis $k$ into account lead to a better agreement with the international relative sunspot number $R_i$, and that yearly $k$ apparently varies with the solar cycle. In this paper, using artificial data sets we have modeled the sunspot numbers as a superposition of random noise and a slowly varying background function, and attempted to investigate whether the variation in the correction factor is coupled with the solar cycle. Regardless of the statistical distributions of the random noise, we have found the correction factor increases as sunspot numbers increase, as claimed in the reports mentioned above. The degree of dependence of correction factor $k$ on the sunspot number is subject to the signal-to-noise ratio. Therefore, we conclude that apparent dependence of the value of the correction factor $k$ on the phase of the solar cycle is not due to a physical property, but a statistical property of the data.

• Korean Journal of Medicinal Crop Science
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• v.11 no.1
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• pp.71-75
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• 2003

To know the varietal difference and yearly changes of lignan contents in the fruits of collected lines of Schizandra chinensis Baillon, three lignan compounds, schizandrin, gomisin A, and gomisin N, were quantitatively analyzed using High Performance liquid Chromatography. The average contents of schizandrin, gomisin A, and gomisin N, showed 0.78%, 0.25%, and 0.63% in the 6-year-old fruits of 24 lines harvested in 1996, and 0.72%, 0.22%, and 0.63% in the 7-year-old ones of 59 lines harvested in 1997. There were the wide range of coefficient of variation (CV) values, the significant differences by the lines and harvest years, and the significant interaction between line and year for lignan contents. Schizandrin contents during 3 years, $1995{\sim}1997$, showed relatively higher amounts more than 0.9% in Chungju 143, Chungju 453, and Chungju 532. Among 23 lines analyzed from 1995 to 1997, Chungju 542, Chungju 547, and Chungju 580 contained continuously higher amounts more than 0.8% of schizandrin and had lower CV values of lignan contents by the harvest years than the other lines. There were a highly significant and negative correlation between fruit weight and lignan contents, and a positive correlation among contents of schizandrin, gomisin A, gomisin N, and total lignan.

• Journal of The Korean Astronomical Society
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• v.36 no.spc1
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• pp.93-99
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• 2003

Various attempts have been made to explain the: pronounced seasonal and universal time (UT) variations of geomagnetic indices. As one of such attempts, we analyze the hourly-averaged auroral electroject indices obtained during the past 20 years. The AU and AL indices maximize during summer and equinoctial months, respectively. By normalizing the contribution of the solar conductivity enhancement to the AU index, or to the eastward electrojet, it is found that the AU also follows the same semiannual variation pattern of the AL index, suggesting that the electric field is the main modulator of the semiannual magnetic variation. The fact that the variation pattern of the yearly-mean AU index follows the mirror image of the AL index provides another indication that the electric field is the main modulator of magnetic disturbance. The pronounced UT variations of the auroral electrojet indices are also noted. To determine the magnetic activity dependence, the probability of recording a given activity level of AU and AL during each UT is examined. The UT variation of the AL index, thus obtained, shows a maximum at around 1200-1800 UT and a minimum around 0000-0800 UT particularly during winter. It is closely associated with the rotation of the geomagnetic pole around the rotational axis, which results in the change of the solar-originated ionospheric conductivity distribution over the polar region. On the other hand the UT variation is prominent during disturbed periods, indicating that the latitudinal mismatch between the AE stations and the auroral electrojet belt is responsible for it. Although not as prominent as the AL index, the probability distribution of the AU also shows two UT peaks. We confirm that the Dst index shows more prominent seasonal variation than the AE indices. However, the UT variation of the Dst index is only noticeable during the main phase of a magnetic storm. It is a combined result of the uneven distribution of the Dst stations and frequent developments of the partial ring current and substorm wedge current preferentially during the main phase.

• Journal of Distribution Science
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• v.16 no.9
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• pp.53-58
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• 2018

Purpose - This study aims to examine how the time variations of customer satisfaction influence retail firms' performance. Research design, data, and methodology - The study employs yearly time series customer satisfaction data of Korean retail secured from the National Customer Satisfaction Index(NCSI) for the 2011~2016 period. Our data includes a total of 90 observations of 15 retail firms in 5 different sector(department store, filling station, large discount store, open market, TV home shopping). We obtained the firm performance data from the KIS Value database. The variables for financial performance include sales and net profit. Results - The results show that customer satisfaction has dynamic effects on retail firms' performance. More specifically, the time variation of customer satisfaction has the moderating effect on the linkage between customer satisfaction and financial performance as well as direct effects on the firms' financial performance. Conclusions - Customer satisfaction has the current effect lasting over time on firm performance and changes of customer satisfaction in positive direction also impact on firm performance. Retail firms need to not only focus on improving customer satisfaction in the current term, but make efforts to continuously enhance customer satisfaction in the long term.