• Water for future
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• v.28 no.6
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• pp.217-228
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• 1995

For optimal reservoir operation during flood period, a general and systematic policy is suggested to make balance of the conflicting purposes between water conservation and flood control. The purpose of this study is to decide the restricted water level of the reservoir during flood period specially to meet water demand in non-flood period. The optimal policy is derived by reallocation of storage capacity through the application of variable restricted water level(VRWL) and minimum required water level(MRWL) for shorter intervals. This study also suggests water level dconditions to secure conservation storage capacity at the end of the flood period estimated by reservoir operation study. This paper illustrates an application of the Daecheong Dam and Chungju Dam respectively during flood and the results are reviewed.

• Journal of the Korean Operations Research and Management Science Society
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• v.24 no.3
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• pp.63-72
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• 1999

Recent studies on the Constant Bit Rate and Variable Bit Rate transmissions have mainly focused on the frame by frame encoder rate control based on the quantization parameter. With the existing approaches it is difficult to guarantee a consistent video quality. Also, the rate control overhead is too high for the real-time video sources. In this paper, a channel rate allocation scheme based on the control period is proposed to transmit a real-time video, in which the control period is defined by a pre-specified number of frames or group of pictures. At each control period, video traffic information is collected to determine the channel rate at the next control period. The channel rate is allocated to satisfy various channel rate constraints such that the buffer occupancy at the decoder is maintained at a target level. If the allocated channel rate approaches the level at which the negotiated traffic descriptions may be violated, the encoder rate is decreased through adjusting quantization parameters in the MPEG encoder. In the experimental results, the video quality and the overflow and underflow probabilities at the buffer are compared at different control periods. Experiments show that the video quality and the utilization of network bandwidth resources can be optimized through the suitable selection of the control period.

• Journal of Korean Society for Atmospheric Environment
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• v.19 no.5
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• pp.469-490
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• 2003

Atmospheric concentrations of persistent organic pollutants (POPs) were measured at Gosan, Jeju in November 2001 and spring 2002, each time for two weeks. Primary target pollutants were organochlorine pesticides, coplanar polychlorinated biphenyls (co- PCBs), and dioxin/furans listed in the Stockholm Convention adopted in May 2001. Polycyclic aromatic hydrocarbons (PAHs) were also measured in order to understand the overall characteristics of the POPs distribution as well as PM$_{2.5}$, a potent carrier of POPs. In the latter part of the measurement period of November 2001, almost every pollutant of combustion origin including dioxin/furans went high probably due to influence of emissions in the nearby area. The characteristics of atmospheric environment at Gosan in this period were rather close to urban areas far from those of a background area. A severe dust storm swept for three days at the end of the measurement period of spring 2002. However, changes in pollutant concentrations were relatively small except PM$_{10}$. Nevertheless, increases in particulate PAHs and OCDD (octachlorinated dibenzo-p-dioxins), mostly present in fine particles, were observed. Trends in organochlorine pesticide variations were mixed although possible volatilization of DDT residues from soil was inferred from the measurements of spring 2002.2.2.

• Earthquakes and Structures
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• v.11 no.4
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• pp.539-561
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• 2016

The rate of occurrence of intraplate earthquake events has been surveyed around the globe to ascertain the average level of intraplate seismic activities on land. Elastic response spectra corresponding to various levels of averaged (uniform) seismicity for a return period of 2475 years have then been derived along with modifying factors that can be used to infer ground motion and spectral response parameters for other return period values. Estimates derived from the assumption of uniform seismicity are intended to identify the minimum level of design seismic hazard in intraplate regions. The probabilistic seismic hazard assessment presented in the paper involved the use of ground motion models that have been developed for regions of different tectonic and crustal classifications. The proposed minimum earthquake loading model is illustrated by the case study of Peninsular Malaysia which has been identified with a minimum effective peak ground acceleration (EPGA) of 0.1 g for a return period of 2475 years, or 0.07 g for a notional return period of 475 years.

• Journal of Applied Reliability
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• v.16 no.2
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• pp.78-89
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• 2016

Purpose: In this paper, we investigate whether the endeavors for Six Sigma quality management by a firm have positive effects on its financial performance and the length of Six Sigma implemented period affects its financial status. We find a relationship between Six Sigma implemented period and several financial performance index using a smoothing spline function. Methods: A smoothing spline function is used in order to analyze the relationship between efforts for quality management and financial performance. Specifically, the return on assets, return on equity, sales cost and business fee are investigated as dependent variables and the efforts for quality management as independent variable. Results: As a result of the analysis, the indication is that companies that put effects into the Six Sigma quality management have a positive result in its financial status. In detail, the efforts for Six Sigma quality management have positive effects on total asset turnover ratio and Six Sigma implemented period on net income to net sales ratio. Additionally, companies with longer (shorter) period of Six Sigma program have more (less) improvement in its financial status. Conclusion: It can be concluded that the company's efforts for quality management positively influence financial performance.

• Journal of Korean Society for Atmospheric Environment
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• v.15 no.2
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• pp.79-87
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• 1999

$^{239+240}Pu$ concentrations in precipitation were determined for the period of May 1994 to August 1996 in oder to describe current $^{239+240}Pu$ deposition at the mid-western coat of Korea (Ansan, 37$^{\circ}$17'N, $126^{\circ}$50'E). $^{239+240}Pu$ concentration in daily precipitation varied from 0.05 to 131$\mu$Bq $kg^{-1}$ with a geometric mean of $1.26\mu$Bq $kg^{-1}$. The concentration was high in the period of Yellow Sand Storm in spring and low in wet summer monsoon. The specific $^{239+240}Pu$ concentration in daily precipitation appears to be controlled by the $^{239+240}Pu$ input to the atmosphere in spring and washout effects by precipitation in the wet summer monsoon. Wet depositional flux of $^{239+240}Pu$ varied from 4 to 123$\mu$Bq $m^{-2}d^{-1}$ with a geometric mean of $33.8\mu$Bq $m^{-2}d^{-1}$ and with a maximum in the period of Yellow Sand Storm and a minimum in the period of wet summer monsoon. $^{238}Pu$/$^{239+240}Pu$ activity raios(0.04~0.31) in precipitation for March-June period suggested that one of the major sources of Pu isotopes falling in Ansan area is the arid region of the Chinese continent.

• Environmental Analysis Health and Toxicology
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• v.6 no.1_2
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• pp.7-23
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• 1991

The present study was undertaken to examine the effect of butylhydroxyanisole (BHA) on the lead poisoning in Wister female rats. All experimental rats except normal group were fed with diets formulated by adding BHA in a range of 0.1% to 3.2% and aqueous solution of 1% lead acetate ad libitum through the experimental period. The results obtained are summarized as follows: 1) Lead sedimentation in kidney tissue was decreased with increasing experimental period and BHA level of lead plus BHA-treated groups in comparison with that of lead-treated control group. 2) The weights of lung, spleen and left/right (L/R) kidney were significantly decreased in comparison with those of lead-treated control group after 2 weeks of experimental period, but no difference was shown with those of normal group. 3) The weights of lung, spleen and L/R kidney were increased in lead-treated control group as compared with normal group after 2 weeks of experimental period, but no difference was shown with increasing experimental period. 4) Water intake was remarkably decreased in lead-treated control group as compared with normal group, but water intake by increasing BHA level of lead plus BHA-treated groups showed no significant difference from that of normal group. 5) These results suggest that BHA is effective for reducing the toxic effect of lead in rats.

• Journal of Korean Medical classics
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• v.27 no.4
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• pp.39-53
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• 2014

Objectives : Hajae's Diary(荷齋日記) is a personal diary written by Gyu-Sik Ji(池圭植) between 1891 and 1911. He had a strong interest in medicine and maintained the belief that diseases could be cured by medicine. He recorded in significant detail the subject individuals, symptoms, name of prescription, price, the date of exchange and place of purchase in his diary. Methods : His study classifies the era during which Western medicine was introduced to the general public and became popularized in the late Chosun dynasty period based on articles related to medicine in Hajae's Diary. Results : It could be identified that, as of the Gabo Reform(甲午更張) in 1894, Western medicine was introduced into the traditional medicine life and, starting from the Eulsa Treaty(乙巳條約) of 1905, Western medicine became popularized. Conclusions : During the "traditional medicine period", traditional medicine was used for all medicinal activities. However, during the "Western medicine introduction period", Western medicine was used for only specific diseases. In the period during which Western medicine became popular, traditional medicine continued to be used. However, Western medicine was widely used for various diseases.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.19 no.2
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• pp.202-211
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• 2006

Objectives : This study is designed to evaluate correlation between the data of D.I.T,I examination in Bell's palsy and the improving period. Methods : This study researched into the clinical statistics for 50 patients who are in Bell's palsy and they are treated with oriental medical care of Dongshin university during 18months from January 1, 2005 to June 1, 2006. The data which examinated by D.I.T.I, are the thermal difference of normal and abnormal site of acupuncture int Gl4 BL2 GB3 S3 S4 S6 TE17 in Bell's palsy. Result : There was statistic significance between thermal difference of normal, abnormal site and the improving period. The period was shorter in normal thermal pattern than hypothermal pattern, hyperthermal pattern. Conclusion : According to the result, there was a statistic significance that more thermal difference and more difficult to recover in Bell's palsy.

• Korean Journal of Veterinary Research
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• v.57 no.3
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• pp.189-195
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• 2017

The isolation rate of Escherichia (E.) coli in poultry litter was investigated at 44 broiler farms, 20 that used fresh litter and 24 that used recycled litter. The patterns of resistance to antibiotics of the E. coli isolates were compared. In litter sampled before the rearing period, the isolation rate of E. coli was higher at farms that used fresh litter; E. coli was present in the litter in 94.5% (35 out of 37 flocks tested) of the farms that used fresh litter vs. 51.2% (21 out of 41 flocks) of the farms that used recycled litter. The susceptibility of the 93 isolates of E. coli to 13 antibiotics was studied. Before the rearing period, E. coli isolates from the farms that recycled litter showed higher resistance rates than isolates from farms that replaced litter with fresh litter. Comparing the antibiotic resistance patterns of isolates from litter sampled before and at the end of the rearing period, the antibiotic resistance rates at the end of the rearing period increased dramatically compared with rates before the rearing period.