• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.235-237
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• 1996

This paper shows a reasonable power demand method and load characteristics in underground streets, that was made by the systematic and statistical way considering actual conditions, such as investigated electric equipment capacity, electric power consumption, load characteristics, etc for 13 underground streets.

• Korean Management Science Review
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• v.12 no.3
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• pp.163-175
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• 1995

The future demand of the satellite broadcasting service is analyzed through the competitive diffusion model. Diffusion rates of the satellite broadcasting service in the case that the decreasing effect due to the cable TV service is considered are smaller than those in the independent case. Diffusion rates of the satellite broadcasting service are shown to become different according to environmental conditions.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.67-74
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• 2008

The regional-scale transient groundwater-river interaction model is developed to gain a better understanding of the regional-scale relationships and interactions between groundwater and river system and quantify the residual river flow after groundwater abstraction from the aquifers with climate variability in the Waimea Plains, New Zealand. The effect of groundwater abstraction and climate variability on river flows is evaluated by calculating river flows at the downstream area for three different drought years (a 1 in 10 drought year, 1 in 20 drought year, and 1 in 24 drought year) and an average year with metered water abstraction data. The effect of future water demand (50 year projection) on river flows is also evaluated. A significant increase in the occurrence of zero flow, or very low flow of 100 L/sec at the downstream area is predicted due to large groundwater abstraction increase with climate variability. Modeling results shows the necessity of establishing dynamic cutback scenarios of water usage to users over the period of drought conditions considering different climate variability from current allocation limit to reduce the occurrence of low flow conditions at the downstream area.

• Structural Engineering and Mechanics
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• v.31 no.1
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• pp.93-112
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• 2009

In this study seismic analyses of steel structures were carried out to examine the effect of ground motion characteristics and structural properties on energy demands using 100 earthquake ground motions recorded in different soil conditions, and the results were compared with those of previous works. Analysis results show that ductility ratios and the site conditions have significant influence on input energy. The ratio of hysteretic to input energy is considerably influenced by the ductility ratio and the strong motion duration. It is also observed that as the predominant periods of the input energy spectra are significantly larger than those of acceleration response spectra used in the strength design, the strength demand on a structure designed based on energy should be checked especially in short period structures. For that reason framed structures with buckling-restrained-braces (BRBs) were designed in such a way that all the input energy was dissipated by the hysteretic energy of the BRBs, and the results were compared with those designed by conventional strength-based design procedure.

• Journal of the Korean Society of School Health
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• v.19 no.2
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• pp.1-12
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• 2006

Purpose： The purpose of this study was to investigate the current conditions and to analysis the needs of health education contents in school nurses and elementary school children. Methods : The survey was conducted through the questionnaire with school nurses and students. Subjects were 60 school nurse and 1483 elementary school children. Data was collected based on the from Mar to Apr. 2004. Finally, data was analyzed using mean, SD, and t-test. Results : The students need the health education related safety, oral hygiene, visual promotion, scoliosis prevention, cyber addiction prevention, anti-bullying and school violence prevention. School nurses suggest the contents of health education such as sex education, drug misuse and overuse prevention. There was also a difference in the need of health education among the school nurse and students. Conclusion：I suggest that health education should be conducted taking students' demand in each grade into consideration. School nurses need to positively improve the priorities of health education based on the students' demand.

• Industrial Engineering and Management Systems
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• v.1 no.1
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• pp.29-45
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• 2002

In this study, we consider infinite supply of raw materials and backlogged demands as given two boundary conditions. And we need not make any specific assumptions about the inter-arrival of external demand and service time distributions. We propose a numeric model and an algorithm in order to compute the first two moments of inter-departure process. Entropy enables us to examine the convergence of this process and to derive measurable relations of this process. Also, lower bound on the variance of inter-departure process plays an important role in proving the existence and uniqueness of an optimal solution for a numeric model and deriving the convergence order of augmented Lagrange multipliers method applied to a numeric model. Through these works, we confirm some structural properties and numeric examples how the validity and applicability of our study.

• Journal of Korean Society of Transportation
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• v.10 no.3
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• pp.21-42
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• 1992

As for the travel demand analysis of the past, forcasting has been conducted by the use of revealed preference(RP) informations about actual or observed choices made by individuals. Forcasting method using RP data needs implicit assumptions that there will be no remarkable changes in existing transport conditions. However in case of occuring the great changes in existing conditions or adding a new choice-set of hypothetical options, it is very difficult to predict future travel demand. Fortunately in recent years, especially in the mode choice analysis, it has been perceived that the importance of individual performance data using stated preference(SP) experiments as well as RP data. But the research reports has not been reported sufficiently from models estimated using SP data. Under this background, we analyze the factors affecting the mode choice behavior as a fundamental study against the modelling task with SP choice data. For this analysis, we assumed subway operations in the secondary cities where there are no subway lines until now, and set up a choice-set of hypothetical options based on Experimental Design Method.

• Journal of the Korean Society for Railway
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• v.16 no.5
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• pp.372-378
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• 2013

This paper presents an approximate model for computing the peak demand power in a metro railway system. The peak demand of substations can be calculated using the current vector iteration method. But the existing method requires many repeated calculations to determine the peak demand power, which makes it difficult to apply to the real-time peak power control problem. In this paper, we assume that none of the conditions vary except source impedance and make an approximate model for rapid calculation based on changes in the impedance of the power substation. The proposed model result is approximately the same as the existing model, which is demonstrated through simulation.

• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.2
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• pp.15-26
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• 2012

For stable and sustainable crop production, understanding the effects of climate changes on agricultural water resources is necessary to minimize the negative effects which might occur due to shifting weather conditions. Although various studies have been carried out in Korea concerning changes in evapotranspiration and irrigation water requirement, the findings are still difficult to utilize fordesigning the demand and unit duty of water, which are the design criteria of irrigation systems. In this study, the impact analysis of climate changes on the paddy water demand and unit duty of water was analyzed based on the high resolution climate change scenarios (specifically under the A1B scenario) provided by the Korea Meteorological Administration. The result of the study indicated that average changes in the paddy water demand in eight irrigation districts were estimated as -2.4 % (2025s), -0.2 % (2055s), and 3.2 % (2085s). The unit duty of water was estimated to increase on an average within 2 % during paddy transplanting season and within 5 % during growing season after transplanting. This result could be utilized for irrigation system design, agricultural water resource development, and rice paddy cultivation policy-making in South Korea.

• Journal of the Korean Regional Science Association
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• v.6 no.1
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• pp.39-55
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• 1990

The principal measure of housing demand is income and the preferences expressed by households through their respective indifference curves. In this context, housing essentially becomes a derived demand, i.e., the household consumes land and a location (or distance-in time and money costs), according to its relative preferences for space, accessibility, and all other nonhousing goods. This paper attempts to deal with both aspects of housing (apartment) demand and household mobility in the Seoul Metropolitan Areas. Housing services will be measured using hedonic regression technique. From observations on the market prices of dwelling units and on the underlying characteristics of housing, one can estimte the relationships between the two empirically. In predicting the probability of the future moves into new towns in the Seoul Metropolitan areas, the best predictors of the future moves into new best predictors are found to be the degree of satisfaction not only with the current residence as a whole, but with some of the major amenities, accessibility and child education. The reasons for moving into new towns are diverse depending on the households' current situation; the most frequently cited is "improvement of housing conditions," followed by "improvement of living environment," "asset improvement" and "home ownership". It appears that people move houses because of a dissatisfaction with their current housing status, relative their income or needs, or a desire to improve their housing and neighborhood amenities, or both. On the other hand, it is clear that the development of new towns in the Seoul Metropolitan Areas should be based on the analysis of housing demand and the pattern of household mobility in Seoul housing market.sehold mobility in Seoul housing market.