• Journal of Wetlands Research
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• v.19 no.4
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• pp.491-500
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• 2017

Stream water quantity is the most basic, fundamental and important element for stream water quality and for conservation of ecological environment. This study aims to analyze causes of changes in stream water quantity based on the percentage of impervious surface area (%ISA) in urban streams of Gyeonggi-do, and also to present a method to secure water quantity of urban streams in Gyeonggi-do and data to be applied to River Management Policy. For this purpose, the Anyangcheon watershed, the Tancheon watershed, and the Osancheon watershed were selected as samples of the urban streams. In addition, the stream water quantity and the changes in stream water quality which were based on the amount of ISA, and methods to directly and indirectly secure stream water quantity were investigated. The results are as follows. The amounts of ISA of the Anyangcheon watershed, of the Tancheon watershed, and of the Osancheon watershed showed a 5.32%, 6.32%, and 7.22% increase, respectively, from 2014 which was approximately 10 years ago. The runoff coefficient generally increased as the amount of ISA was increased. Water reuse quantity of stream in the Tanchon watershed had a positive effect on securing stream water quantity, but both in the Anyangcheon watershed and in the Osancheon watershed, it did not have a positive effect on that. However, water reuse quantity of stream improved the water quality of each stream.

• Journal of Korean Society on Water Environment
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• v.33 no.2
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• pp.140-148
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• 2017

An important factor in determining the design and treatment efficiency of wastewater treatment plants (WWTPs) is the quantity and quality of influent. These detailed and accurate information is essential for process control, diagnosis and operation, as well as the basis in designing the plant, selecting the process and determining the optimal capacity of each bioreactor. Probabilistic models are used to predict the wastewater quantity and quality of WWTPs, which are widely used to improve the design and operation of WWTPs. In this study, the optimal probability distribution of time series influent data was derived for predicting water quantity and quality, and wastewater influent data were generated using the Monte Carlo simulation analysis. In addition, we estimated various alternatives for the improvement of bioreactor operations based on present operation condition using the generated influent data and activated sludge model, and suggested the alternative that can operate the most effectively. Thus, the influent quantity and quality are highly correlated with the actual operation data, so that the actual WWTPs influent characteristics were well reproduced. Using this will improve the operating conditions of WWTPs, and a proposed improvement plan for the current TMS (Tele Monitoring System) effluent quality standards can be made.

• Journal of Families and Better Life
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• v.22 no.2
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• pp.23-35
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• 2004

The purpose of this study is to evaluate child - care effects on young child's aggression in ecological context. For this, main effects, interaction effects and cumulative effects between child care experiences(quantity, quality, age of entry and stability) and maternal behavior as well as characteristics of child(sex, age and temperament) were examined. A total of 62 young children(34 boys and 28 girls) enrolled in child - care center were observed, and mothers and caregivers completed questionnaires. Data was analysed by three - way ANOVA, logistic regression and crosstabs. As result, first, main effects of quantity, rejective and regulative mothering on children's aggression were found. Second, there were significant interaction effects between both quality and quantity of day-care and rejective mothering. In particular, the interaction effects provided evidence that high - quality child - care served a compensatory function for extensive care and rejective mothering. Third, logistic regression analysis revealed risk factors for child's aggression and the effects of these risk factors were cumulative. Interaction effects of day-care quality and cumulative effects of day-care, characteristics of child and maternal behavior on child aggression were discussed.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1996.04a
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• pp.298-301
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• 1996

This paper addresses the effects of an imperfect production process on the optimal production quantity and quality inspection policies. The system is assumed to deteriorate during the production process. The results are either defective products or machine breakdown whether multiple quality inspection is worth or not. Furthermore, when multiple inspection policy is adopted, the optimal inspection schedule is shown to be equally spaced throughout the production cycle. Exact solution and approximation of the optimal production quantity and approximation of the optimal number of inspection are provided. Finally, to better understand the model of this paper, comparisons between this model and classical EMQ model are provided.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1999.10c
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• pp.550-555
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• 1999

yongdam multipurpose is under construction to divert a part fo Geum riverlfow to Mankyung watershed and to supply the domestic water to the Chunju region and produce the hydro-electricity. Generally construction of dam by the method of inther-region water transfer affects the quantity and quality of water inthe down streams and reservoirs. The impact of operation plan of Yondgam dam on the quantity and quality of water in the Guem river and Daechung dam was investigated .It was recommended that the discharge of water transfer from one watershed to another should be minimized as much as possible.

• Industrial Engineering and Management Systems
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• v.6 no.2
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• pp.136-145
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• 2007

The selection of suppliers and the determination of order quantities to be placed with those suppliers are important decisions in a supply chain. In this research, a non-linear mixed integer programming model is presented to select suppliers and determine the order quantities. The model considers the purchasing cost which takes into account quantity discount, the cost of transportation, the fixed cost for establishing suppliers, the cost for holding inventory, and the cost of receiving poor quality parts. The capacity constraints for suppliers, quality and lead-time requirements for the parts are also taken into account in the model. Since the purchasing cost, which is a decreasing step function of order quantities, introduces discontinuities to the non-linear objective function, it is not easy to employ traditional optimization methods. Thus, a heuristic algorithm, called particle swarm optimization (PSO), is used to find the (near) optimal solution. However, PSO usually generates initial solutions randomly. To improve the PSO solution quality, a heuristic procedure is proposed to find an initial solution based on the average unit cost including transportation, purchasing, inventory, and poor quality part cost. The results show that PSO with the proposed initial solution heuristic provides better solutions than those with PSO algorithm only.

• Water Engineering Research
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• v.2 no.2
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• pp.103-112
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• 2001

Issues and problems in formulating South Korea's water resources policy are discussed in terms of water quantity and quality. South Korean needs both water conservation and water supply capability for the growing population and economic activities. The government has attempted to build more large-scale dams to store and supply water for residential, farming and industrial uses, but the environmentalists who emphasize conservation and environmental protection oppose the government. The environmentalists are popular among the general public. Water quality has been deteriorating from point- ad non-point sources. urban and farm runoffs are serious pollutants. All want by preserve water quality. There is no dispute on this matter between the government and the environmentalists. Money is hard to come by to preserve water quality. Economic and financial crises and no self-sufficient local governments' revenue structure are pessimistic. Basic survey on water resources, hydrology and hydraulic is badly needed for the future water resources planning.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.10 no.15
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• pp.39-44
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• 1987

A model for obtaining optimal target value and optimal production quantity of the process is described when the mean quality characteristic decreases according to the increase of production quantity. Two different cases are considered where defective items can be either sold at a reduced unit price or discarded. Some numerical examples are also given.

• Korean Journal of Radiology
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• v.22 no.11
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• pp.1909-1917
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• 2021

Objective: Muscle quantity and quality can be measured with an automated system on CT. However, the effects of contrast phases on the muscle measurements have not been established, which we aimed to investigate in this study. Materials and Methods: Muscle quantity was measured according to the skeletal muscle area (SMA) measured by a convolutional neural network-based automated system at the L3 level in 89 subjects undergoing multiphasic abdominal CT comprising unenhanced phase, arterial phase, portal venous phase (PVP), or delayed phase imaging. Muscle quality was analyzed using the mean muscle density and the muscle quality map, which comprises normal and low-attenuation muscle areas (NAMA and LAMA, respectively) based on the muscle attenuation threshold. The SMA, mean muscle density, NAMA, and LAMA were compared between PVP and other phases using paired t tests. Bland-Altman analysis was used to evaluate the inter-phase variability between PVP and other phases. Based on the cutoffs for low muscle quantity and quality, the counts of individuals who scored lower than the cutoff values were compared between PVP and other phases. Results: All indices showed significant differences between PVP and other phases (p < 0.001 for all). The SMA, mean muscle density, and NAMA increased during the later phases, whereas LAMA decreased during the later phases. Bland-Altman analysis showed that the mean differences between PVP and other phases ranged -2.1 to 0.3 cm² for SMA, -12.0 to 2.6 cm² for NAMA, and -2.2 to 9.9 cm² for LAMA.The number of patients who were categorized as low muscle quantity did not significant differ between PVP and other phases (p ≥ 0.5), whereas the number of patients with low muscle quality significantly differed (p ≤ 0.002). Conclusion: SMA was less affected by the contrast phases. However, the muscle quality measurements changed with the contrast phases to greater extents and would require a standardization of the contrast phase for reliable measurement.

• The Journal of Pediatrics of Korean Medicine
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• v.25 no.3
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• pp.57-69
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• 2011

Objectives: Purpose of this study is to analyze and to estimate which and how much genetic and environmental factors have affected on growth. Also, a method of final height prediction can be developed from this study results. Methods: Correlation analysis and categorical regression analysis were conducted between genetic and environmental factors correlated with the final adult height, through survey from 171 male. Results: Mid parental height, neonatal body weight, intake frequency of beef, chicken, milk, fruits and coffee, sleep quantity and quality during the elementary school and sleep quantity during the middle school have affected on the final adult height. And a regression equation with 0.494 for coefficient of determination was obtained. Conclusions: Mid-parental-height has the most affected on the final adult height. Among environmental factors, food and sleep have significantly affected, but exercise doesn't. Among foods, meal, beef, and milk intake have remarkably affected on the final height, and chicken and fruit also have affected in some degree, but coffee has affected badly. Among sleep habits, sleep quantity during the elementary school has the most affected, sleep quality during the elementary school and sleep quantity during the middle school also have affected in some degree on final height. The younger the age is, the more sleep have affected and sleep quantity have more affected than sleep quality. Neonatal weight also has remarkably affected on the final height. Through this analysis, the final adult height can be predicted using regression equation which covers 49.4% of genetic and environmental factors.