• Journal of Korea Water Resources Association
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• v.40 no.5
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• pp.397-407
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• 2007

The deposition of sewer solids during dry weather in combined sewer systems results in a loss of flow capacity that may restrict flow and cause a local flooding and enhanced solids deposition. In order to solve these problems and to manage sewer systems efficiently, development of estimation equations for solid sediments In sewer systems is needed. However, estimation of solid sediments has performed using specific methods such as computer model before the development of estimation equations. In this study, solid sediments in sewer systems were estimated using MOUSE model for Gunja drainage basin in Korea and the estimated results were verified using estimation equations developed by the U.S. Environmental Protection Agency. As results, the estimated values using MOUSE model are smaller than that of equations developed in 1977 but greater than that of equations developed in 1984. Although the comparison between simulated and measured solid deposition is difficult due to the absent of measurement data, the estimated values using MOUSE model is reliable and can be used to develop estimation equations for solid sediment in Gunja drainage basin.

• Journal of Korea Water Resources Association
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• v.42 no.11
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• pp.1017-1028
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• 2009

NSRPM (Neyman-Scott Rectangular Pulse Model) is one of the common model for generating future precipitation time series in stochastical hydrology. There are 5 parameters to compose the NSRPM model for generating precipitation time series. Generally parameter estimation using moment has some problems related with increased objective functions and shows different results in accordance with random variable generating models. In this study, direct parameter estimation method was proposed to cover with disadvantages of parameter estimation using moment. To apply the direct parameter estimation, generating stochastical data variance in accordance with numbers of precipitation events of NSRPM was done. Both kinds of methods were applied at the Cheongju gauge station data. Precipitation time series were generated using 4 different random variable generator, and compared with observed time series to check the accuracies. As a results, direct method showed more stable and better results.

• Water for future
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• v.50 no.1
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• pp.18-25
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• 2017

• Water for future
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• v.45 no.4
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• pp.52-58
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• 2012

• Water for future
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• v.22 no.4
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• pp.409-410
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• 1989

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1456-1461
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• 2004

Companies of Build-to-Order(BTO) strive to achieve customer responsiveness and cost efficiency simultaneously. The success of BTO depends upon the high volume production based on product plat form and delayed differentiation principle on the one hand, and upon the rapid estimation of delivery and cost for the customer orders on the other hand. Expeditious processing of a specific order requires the rearrangement of production resources and the schedule, which results in increased cost. This paper describes a cost estimation method using activity-based costing depending on the schedule change caused by urgent customer orders.

• International Journal of Internet, Broadcasting and Communication
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• v.12 no.2
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• pp.21-29
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• 2020

This paper presents an effective single image haze removal using edge-preserving and adaptive transmission estimation to enhance the visibility of outdoor images vulnerable to weather and environmental conditions with computational complexity reduction. The conventional methods involve the time-consuming refinement process. The proposed transmission estimation however does not require the refinement, since it preserves the edges effectively, which selects one between the pixel-based dark channel and the patch-based dark channel in the vicinity of edges. Moreover, we propose an adaptive transmission estimation to improve the visual quality particularly in bright areas like sky. Experimental results with various hazy images represent that the proposed method is superior to the conventional methods in both subjective visual quality and computational complexity. The proposed method can be adopted to compose a haze removal module for realtime devices such as mobile devices, digital cameras, autonomous vehicles, and so on as well as PCs that have enough processing resources.

• Journal of Soil and Groundwater Environment
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• v.17 no.2
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• pp.1-6
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• 2012

Total Economic Value (TEV) provides a framework to estimate the economic value of water resources including groundwater with multiple applications to natural resource economics and environmental economics. Crucial to the application of economic analysis to natural resources are techniques to value the resources as an economic value that is expressed in monetary terms. On the other hand, the aim of TEV estimation is to determine the economic value of water resources including 'use' with production and recreation and 'non-use' such as existence values. TEV is used to assess the economic value of water resources for the multiple goods, and environmental 'services' that are provided by a water resource and also used to assess options for water use, for example balancing production values provided by water resource use against the cost of resource degradation by that use. The value of TEV can be assessed over time where pollution or unsustainable use may reduce the economic value of an environmental asset. Therefore, values are used to assess options of resource use, sometimes leading to policies on resource conservation or allocation. In conclusion, the application of TEV would be well adjusted over Jeju Island where groundwater resources account for more than 98% water resources and the budget of water demand/supply shows disparity over the Island.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.75-81
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• 2008

The water shortage in mega cities in Asia, which face a rapid growth in urban population, is an outstanding problem. It is important, therefore, to accurately estimate the water balance in each city in order to use the limited water resources effectively. In this study, we estimated the potential water resources in し sixteen mega cities in Asia. The target cities were Delhi and Calcutta, India; Colombo, Sri Lanka; Dhaka, Bangladesh; Yangon, Myanmar; Bangkok, Thailand; Kuala Lumpur, Malaysia; Singapore; Jakarta, Indonesia; Hanoi, Vietnam; Beijing and Hong Kong, the People's Republic of China; Seoul, the People's Republic of Korea; Manila, the Philippines, and Sapporo and Tokyo, Japan. The potential water resources were estimated by subtracting the actual evaporation from the amount of rainfall. The actual evaporation was estimated using the potential evaporation obtained by Hamon's equation which requires the air temperature and the possible hours of sunshine. When the results of Hamon's and Penman's evaporation equations were compared, a considerable error appeared in the low latitude region. The estimation using Hamon's equation was corrected with the linear regression line of Hamon's and Penman's equations. A classification of the land cover was carried out based on satellite photographs of the target cities, and the volume of surface runoff for each city was obtained using the runoff ratios which depended on the land cover. As a result, the potential water resources in the above mega cities in Asia were found to be greater than the world average. However, the actual water resources which are available for one person to use are probably very limited.

• Journal of Korea Society of Waste Management
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• v.35 no.8
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• pp.770-776
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• 2018

This study measured the energy recovery rate of each municipal waste incineration facility according to the revised energy recovery rate estimation method, which targeted four municipal waste incineration facilities (Unit No. 7). The results calculated by the measuring instruments were used for each factor to estimate the recovery rate, and the available potential of available energy was examined by analyzing the energy production and valid consumption. As a result of the low heating value, 2,540 kcal/kg was calculated on average when the LHVw formula was applied, which is approximately 116 kcal/kg higher than the average design standard of 2,424 kcal/kg. The energy recovery rate was calculated as 96.9% on average based on production and 67.5% based on effective consumption, and the analysis shows that approximately 29.4% energy can be used.