• Solar Energy
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• v.20 no.1
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• pp.97-108
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• 2000

The purpose of this study is to minimize the heat transfer surface area and cold fluid exit temperature of heat exchanger which applied to the refrigeration and air-conditioning system by utilizing the thermoelectric principle. Both uniform and non-uniform current distribution methods which applied to the analysis of the TE elements that incorporates heat exchanger were investigated. The non-uniform current distribution method had the better coefficient of performance and had the lower cold fluid exit temperature of the TE cooling system than the uniform current distribution method. It was found that if a TE cooling system incorporates a heat exchanger, a non-uniform current distribution should guarantee to the lowest cold fluid exit temperature. Also, the hybrid method (combination of the uniform and non-uniform current distribution method) is investigated to achieve the best results by combining the uniform and non-uniform current distributions. The results show that it can lower the cold fluid exit temperature and reduce the heat transfer surface area for the parallel flow arrangement if we apply the constant current in some entry region and the non-uniform increasing current in the direction of the cold fluid flow afterwards.

• Journal of Korean Society of Water and Wastewater
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• v.28 no.3
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• pp.345-358
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• 2014

For introducing the groundwater quality assessment using background concentration of groundwater, several methods had been studied to estimate the background concentration of groundwater and to suggest the background concentration of study area. Some methods such as Box whisker plot, Percentile and Cumulative probability distribution had been adopted to estimate background concentration, and it was evaluated that the Cumulative probability distribution method presents more reasonable background concentration because it can consider the data distribution. So we estimated the background concentration of study area using cumulative probability distribution method. We suggested the background concentration for each hydrogeology respectively in case hydrogeological water quality similarity is very low.

• Proceedings of the KIEE Conference
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• 1999.07c
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• pp.1481-1483
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• 1999

Power distribution system planning for maximum customer satisfaction and system efficiency requires accurate forecast of future demand in service area. Spatial load forecasting method provides a more accurate estimation of both magnitudes and location of future electrical load. This method considers the causes of load growth due to addition of customers and per capita consumption among customers by land use (residential, commercial and industrial). So the land-use study and it's preference for small area is quite important. This paper proposes land-use preference estimation method based on fuzzy logic. Fuzzy logic is applied to computing preference scores for each land-use and by these scores the customer growth is allocated in service area. An simulation example is used to illustrate the proposed method.

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.1495-1498
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• 2002

The constrained average method is one of dither methods which combines edge emphasis and grayscale rendition to provide legibility of textual region and proper quality of continuous tone region. How-ever, image quality of continuous tone region is insufficient compared to other dither methods, such as ordered dither methods or the error diffusion method. The constrained average method uses a uniform distribution function to decide number of lit pixels related to the average intensity in a picture area. However, actual distribution of continuous tone region is closer to the Laplacian distribution or triangle distribution. In this paper, we introduce various probability distributions and the actual luminance distribution to decide the threshold value of the constrained average method in order to improve image quality of dithered image.

• Journal of Environmental Health Sciences
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• v.27 no.2
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• pp.100-107
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• 2001

On the planning for the systematic management and control of the air pollution display methods were used to evaluate the spatial pollutant concentration status. This study were conducted to investigate the practical using of Geographic Information System(GIS) technology on the air pollution control and management which were computer-based systems that were used to store and manipulate geographic information in the macro city. In this study 137 samples were corrected by passive samplers and analysed by GC/MSD for 16 VOCs in Seoul (25 distincts) distributed by TM-coordinate(2 km$\times$2km), and finally displayed by Arciew program(version 3.2, ESRI Inc, USA) for windows. The concentration of benzene and toluene showed high level in whole area of seoul area of Seoul and distribution of butylbenzen, trothroloetylene, stylen showed high level in whole area of Seoul except a few distincts and the distribution of isopropylbenzene, 1,2-dichroloethane showed higher level in core area than that of Kangnam and Kangbuk area. In conclusion, products of this study of using GIS technology apply on the spatial distribution of VOCs concentration was very effective than that of other methods(e.g., contouring concentration method, pie or column chart, graduated symbols), especially in mapping and symbolization of pollution status evaluation.

• Journal of Distribution Science
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• v.10 no.12
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• pp.5-11
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• 2012

Purpose - This paper proposes measurement models to evaluate the management performance of small and medium-sized retail businesses on the basis of a trading area analysis that compares their proposed revenue to actual revenue in the trading area. Research design, data, methodology - The study proposes measurement models consisting of five stages, namely: (1) district background survey, (2) customer survey, (3) competitor survey, (4) business district survey, and (5) business performance analysis. Results - To identify business districts easily, this study preferred a minor-adjusted method based on the Euclidean distance, as it is simple to employ for the small and medium-sized businesses. This model was applied to select coffee shops in Daejeon. Results indicated that although the targeted shop was not located in an appropriate location, actual sales were higher than expected. Conclusions - Small- or medium-sized retail businesses face difficulties regarding the economies of scale and brand recognition and must choose an appropriate location to ensure management stability. However, such businesses will find it difficult to evaluate their competitive edge accurately using a trading area analysis.

• Journal of Korean Society of Water and Wastewater
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• v.33 no.4
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• pp.299-309
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• 2019

Waterworks facilities inevitably experience some amount of leakage even if there is a lot of investment or state-of-the-art technology that is applied such as DMA(District Metered Area) system construction, leakage detection, repair, pipe rehabilitation, etc. The primary reason is the leakage is naturally restored over time. In the UK, this restoration characteristic is defined as NRR(Natural rate of rise of leakage) and used to decision making for prioritizing active leakage control of DMAs. However, this restoration characteristic is well recognized, but researches on NRR in the water distribution system are insufficient in Korea. In this study, the estimation method of NRR was developed suitable for applicating in Korea considering of SCADA data, water infrastructure, and water usage patterns by modification of the UK's NRR method. The proposed method was applied to 9 DMAs and verified it's applicability by comparing with the other water loss performance indicators. It is expected that the proposed method can be used to support decision making for sustainable NRW(Nor-revenue water) management in the water distribution system.

• Journal of the Korean Solar Energy Society
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• v.23 no.4
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• pp.71-80
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• 2003

The purpose of this study is to analyze the window area ratio distribution of building facade in Tokyo metropolitan area. The survey was carried out in Marunouchi, Kanda, Kasai and Todoriki district. The results of this study were as follows; to propose of window area ratio production method, analyzed and surveyed window area ratio of each district building-used and to compared every wall window area ratio of building. Every wall window area ratio of office district is $20\sim40%$, ones of non-office district is 15% or 35%. Residential area results are every wall window area ratio of apartment is 35%, ones of a house is 15%. To increase of office building to appear that Kanda, Kasai added window area ratio. But, Marunouchi, Todoriki wad not this tendency. Above mentioned results are made out database.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2000.02a
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• pp.22-25
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• 2000

To improve the performance of high temperature superconducting current leads, variable cross-sectional area is considered. The cross-sectional area is varied as a function of current density to fix the safety factor along lead length. New integration method is devised to find optimum cross-sectional area distribution. New design of current lead has low heat leak into cryostat and less material than constant cross-sectional area leads. Conduction cooled lead is considered. The developed method is applied to Bi2223 current leads sheathed Ag-Au alloy.

• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.5
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• pp.49-58
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• 2013

Appropriate random variables and probability density functions based on statistical analysis should be defined to execute reliability analysis. Most studies have focused on only normal distributions or assumed that the variables showing non-normal characteristics follow the normal distributions. In this study, the reliability problem with non-normal probability distribution was dealt with using the convolution method in the case that the integration domains of variables are limited to a finite range. The results were compared with the traditional method (linear transformation of normal distribution) and Monte Carlo simulation method to verify that the application was in good agreement with the characteristics of probability density functions with peak shapes. However it was observed that the reproducibility was slightly reduced down in the tail parts of density function.