• Journal of Environmental Health Sciences
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• v.47 no.4
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• pp.356-365
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• 2021

Background: Concerns have been raised regarding the criteria of groundwater, in particular in Gwangwon-do Province where many residents drink groundwater due to the poor supply of tap water and a high nonconformity rate with water quality criteria nationwide. Objectives: Water quality monitoring and risk assessment were conducted for groundwater in Hoengseong, Gangwon-do Province. Methods: A total of 46 items required for meeting drinking water criteria were analyzed from 258 samples collected from March 2017 through August 2018 (152 sites in 2017 and 106 sites in 2018). Risk assessment was conducted for two non-carcinogens (F^- and NO₃-N), and one carcinogen (i.e., arsenic) based on their high nonconformity to water quality criteria. Results: Water quality analysis revealed that the total proportion of nonconformities was determined to be 27.9%. The nonconformity rate for each content item is as follows: total colony counts (1.6%), total coliform (6.2%), Escherichia coli (1.2%), F^- (8.1%), arsenic (4.7%), NO₃-N (8.1%), pH (1.2%), manganese (0.4%), and turbidity (5.8%). Risk assessment indicated that fluoride induced a hazard quotient greater than 1 with the 95% UCL (Upper Confidence Limit) concentration of the total 258 sites and average, median, and 95% UCL concentrations of nonconformity sites. For NO₃-N, there was no human health risk. For arsenic, the excess cancer risk exceeded the acceptable cancer risk of 1×10^-6 with the average and 95% UCL concentrations of total 258 sites and average, median, and 95% UCL concentrations of nonconformity sites. Conclusions: This study suggests that it is necessary to expand water quality monitoring of groundwater and conduct a more detailed risk assessment in order to establish a health care plan for the residents of Hoengseong, Gangwon-do Province.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.3B
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• pp.291-300
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• 2006

In this study a statistical water quality monitoring network design of Kyung-An stream is proposed. Water quality data for the design is obtained by QUAL2E model simulation. The observed monthly average water quality data from March to November in Kyung-An stream has been applied to this study. HEC-RAS model is also used for QUAL2E hydrauric parameter estimation. Before QUAL2E water quality parameter estimation, FORA is performed to reduce the number of parameters to be estimated, and then water quality parameters are calibrated with a observed monthly average data. Using these simulated water quality data, the number of gage station and its location are estimated by kriging theory and branch & boundary method. Such a network design is based on two case; average flow and low flow case, respectively. Next, proportional sampling method is applied to estimate the sampling frequency.

• Proceedings of the Korean Society for Quality Management Conference
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• 2004.04a
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• pp.64-69
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• 2004

This research investigates statistical characteristics of variable sampling size & interval(VSSI) X charts under two assignable causes. Algorithms for calculating the average run length(ARL) and average time to signal(ATS) of the VSSI X chart are proposed by employing Markov chain method. Extensive sensitivity analysis shows that the VSSI. X chart is superior to the VSS or VSI X chart as well as to the Shewhart X chart in statistical sense, even under two assignable causes.

• Magazine of the Korean Society of Agricultural Engineers
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• v.39 no.4
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• pp.55-63
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• 1997

Constructed wetland system which can be applied to the rural wastewater treatment system was examined by pilot plant in Kon-Kuk University. Hydraulic loading rate of wastewater was about 0.16m$^3$/m$^2$. day and theoretical detention time in the system was 1.38 days. The effluent of the septic tank for the school building was applied as inflow to the system. The influent concentration of DO was zero but effluent was up to 4.37mg/${\ell}$ which implies that oxygen was supplied enough from atmosphere by reaeration to support biological activity of the system. Average influent concentration of BOD was 104mg/${\ell}$ and effluent was 24mg/${\ell}$ with average removal rate of 76%. Average influent concentration of COD was 215mg/${\ell}$ and effluent was 63mg/${\ell}$ with average removal rate of 70 % . Average influent concentration of SS was 78mg/${\ell}$ and effluent was 10mg/${\ell}$ with average removal rate of 87%. Two components, BOD and SS, are regulated by law to keep maximum water quality standard of 80mg/${\ell}$ when daily outflow rate is less than 100$m^3$/day which is the case of most rural communities. Therefore, the results from the experiment showed that constructed wetland system can meet the water quality standard easily. Average influent concentration of total nitrogen was 165mg/lwhich is relatively higher than normal wastewater, and effluent was about 156mg/${\ell}$ with average removal rate of only 6%. Average influent concentration of total phosphorus was 41 mg/${\ell}$ and effluent was 6mg/${\ell}$ with average removal rate of 87%. Overall, constructed wetland system was thought to be effective to treat wastewater if nitrogen removal mechanism is improved. Considering low cost, less maintenance, and high treatability, this system can be a practical alternative for the wastewater treatment in rural area The experiment was performed during the summer and fall season, and treatment efficiency of the system is expected to decrease in low temperature. therefore, further study including temperature is required to evaluate feasibility of the system more in detail.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.6 no.2
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• pp.11-20
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• 2003

This research was conducted to investigate the influences of the solifluction soil and amount of flow on the stream water quality of the Bukhansan National Park from March to october, 2002. The average pH of stream water was higher than that caused by solifluction soil. The average electrical conductivity of upstream water was about 2.1~2.8 times lower than that of downstream water. Linear regression analysis showed that pH and amount of anion($Cl^-$, ${NO_3}^-$, ${SO_4}^{2-}$) of stream water were very significantly correlated with those at the caused by solifluction soil. Structures for erosion control along both sides of stream channel should be designed in order not to influence upon solifluction soil and stream water quality.

• Korean Journal of Child Studies
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• v.27 no.4
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• pp.265-278
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• 2006

This study examined the relationship of children's quality of friendship, conflict resolution strategies, and conflict outcomes by peer status. Thirty-four elementary school 5th grade dyads were selected by peer status and friendship status. The major results were that (1) popular children perceived more help and less conflict and rivalry from friends than rejected children. (2) Popular children used more compromising/integrating and less dominating strategies than rejected children to resolve conflicts. Conflicts between popular-average pairs resulted in equal outcomes more often and unresolved outcomes less often than rejected-average pairs. (3) There were significant correlations between friendship quality, conflict resolution strategies, and conflict outcomes by peer status.

• Journal of Korean Society for Quality Management
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• v.26 no.1
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• pp.108-125
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• 1998

The EWMA(Exponentially Weighted Moving Average) has recently received a great deal of attention in the quality control literature as a process monitoring tool on the shop floor of manufacturing industires, since it is easy to plot, to interpret, and its control limits are easy to obtain. Most a, pp.ications of the EWMA for process monitoring have concentrated on the problem of detecting shifts of a process mean and a process standard deviation with ARL(Average Run Length) properties. But there may be the necessity of controlling linearity on product quality such as the correlation coefficient to the process operator. Control managers may want to protect the increase of a process correlation coefficient value, such as 0, between two variables of interest. However, there are few studies concerned on this part. Therefore, we propose EWMA models for a process correlation coefficient using two transformed statistics, T-statistic and (Fisher's) Z-statistic. We also present some results of simulation by SAS/IML and compare two models.

• Journal of Korea Multimedia Society
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• v.22 no.8
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• pp.860-873
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• 2019

LCD backlight boosting and the integration of boosting and dimming are proposed based on image analysis to maximize perceptual image qualities and to reduce display system power. Based on the histogram of the image data, methods for selecting an image suitable for boosting and for adjusting the optimum backlight brightness are proposed. A comprehensive combined optimization method of LCD backlight boosting, dimming and bypass based on image characteristics is also described. Perceptual image quality enhancement and power consumption are evaluated based on well known image databases. Average subjective image quality is improved by 24.8%, RMS contrast is improved more than 20%, and average power consumption is reduced by 15.94% compared to conventional uniform boosting.

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

The quality of water in Kyungan stream was analyzed in three different areas between season of irrigation on May and of nonirrigation on august in 1990. The results of Water quality from this study were summarized as follows: 1. The quality of water is season of irrigation containing metal ions, such as Cu and Zn as well as TN was exceeded standard levels of quality of agricultural water However, in season of nonirrigation, the quality of water in Kyungan stream was not suitable for using agricultural water due to over standard levels of containing ions of Cu and Zn or DO, COD and TN. 2. The correlation of water quality exception of pH was shown a reliance when p values were greater than 0.01 for containing ions such as Cu and Zn with the DO, COD and TN. 3. The comparison of water qualities for pH between season of irrigation and season of nonirrigation in Kyungan stream was a considerable significance property when p values were less than 0.05. The water quality containing ions of Cu and Zn with DO, COD, TN and SS also indicated a significant property when p values were less than 0.01. 4. The average water qualities of a year in three different areas for pH have shown a significant property when p values are less than 0.01. The average water qualities of a year containing DO have also shown a significant property having p values of less than 0.05. But other constituents have shown no significant property in the above three different areas.

• The Korean Journal of Emergency Medical Services
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• v.23 no.3
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• pp.83-96
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• 2019

Purpose: This study was conducted to provide fundamental resource in improving the quality of life and stress by understanding the influence of egoresilience and social support by paramedic students during field practice. Methods: The measurement instrument consisted of 100 questions on the general characteristics, egoresilience, social support, stress, and quality of life of the participants. Frequency and descriptive analysis, t-test, ANOVA, correlation analysis, and multiple regression analysis were performed. Results: The average scores for egoresilience, social support, and stress were 3.00, 3.14, and 1.68 out of 4.00, respectively. The degree of stress was high enough to be statistically significant in the case of women compared to men, and if unsatisfied with one's major. The average quality of life score was 4.50. The degree of quality of life was high enough to be statistically significant in the case of men compared to women, smokers, drinkers, and if content with one's major. Conclusion: It is suggested that colleges develop programs to increase the satisfaction rate of the students and improve their egoresilience and social support. Such programs would improve the quality of life and address the stress experienced by emergency medical technology students.