• Journal of Korea Water Resources Association
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• v.38 no.3 s.152
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• pp.213-222
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• 2005

This study is a sensitivity analysis of the parameters which affect the simulation results under various design rainfall conditions, using the SWMM model, for three selected basins in urban areas. The sensitivity of the peak flow rate is defined by $S_Q$ (=1.0 - (min. ratio of peak flow rate/max. ratio of peak flow rate)), and the rainfall conditions are classified in terms of design rainfall frequency, duration, and distribution. The simulation results show that in most conditions the parameters - the impermeable area ratio, the sewer slope, and the initial infiltration capacity - have more significant effects on the results than other parameters. As the design rainfall frequency increases, the sensitivity of the sewer slope and sewer roughness increases, while the parameters related with the surface runoff decrease. When the rainfall duration increases, the sensitivities of most parameters of surface runoff and sewer flow decrease. Also, at the 1st quarterly Huff rainfall distribution condition, the impermeable area ratio has high sensitivity, but at the 4th quarterly condition the parameters related with sewer flow show higher sensitivities. These tendencies can be explained by considering the procedure for computing the effective rainfall and kinematic wave on the surface and sewer flow.

• Journal of Korea Water Resources Association
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• v.31 no.3
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• pp.253-267
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• 1998

In this study, ILLUDAS and SWMM were applied for Dongsucheon basin, Incheon and Test basin, Cheongju. The main parameters (II, IA, IS, SI, SR, SS) which are included in those of each model depending on runoff results were determined, and sensitivity ratios were estimated in order to evaluate and compare the characteristics of each modEL. Total runoff ratio for almost parameters turned out to have a linear relation to the rainfall durations and the scale of basin area but have nothing to do with rainfall distributions. Sensitivity ratios turned out to have a linear relation for the infiltration and soil parameters of ILLUDAS as well as all parameters of SWMM. ronoff sensitivity ratios for almost parameters were smaller than 1.0 because the impacts of total runoff were bigger than those of peak runoff. And runoff sensitivity ratio was equal to 1.0 for the roughness coefficient of SWMM. Total runoff ratio, peak runoff ratio and runoff sensitivity ratio for the selected parameters of those models were presented asthe tables and figures according to the scale of basin area, rainfall durations such as 60, 120, and 180 minutes and Huff's 4th quartiles rainfall distributions. Keywords : ILLUDAS, SWMM, parameter, sensitivity analysis, sensitivity ratio.

• Journal of Korea Water Resources Association
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• v.40 no.1 s.174
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• pp.25-38
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• 2007

A grid-based urban surface runoff model for simulating the temporal variation and spatial distribution of overland flow in a drainage area was developed. The process of routing of overland flow is modeled by the nonlinear storage equation which is composed of the continuity equation and the Manning's equation. For model operation, the drainage area is divided into grid areas, and spatially distributed topographical and hydrological information for model inputs is provided. Then overland flow is routed for each of the discretized cells of the area. In order to test the applicability of this model, temporal variations and spatial distributions of flow depth and overland flow was simulated in a fictitious and a real urbanized Kunja drainage area. Results indicate that the model can simulate reasonably well the urban runoff hydrograph.

• Water for future
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• v.29 no.6
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• pp.189-201
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• 1996

The main objective of this study is to determine the time distribution models of rainfall in Korea for estimating design floods and to suggest new runoff model(Geomorphologic Instantaneous Unit Hydrograph; GIUH) in order to be easily use the rainfall-runoff model put rainfall models practice to be suitable for the regional characteristics of hydrologic situation by practicing engineers. As a result, the reappearance of triangular hyetograph and GIUH runoff model showed promising. The historical data from about 13,000 event-rainfalls and 73 rainfall-runoff measuring data during 12 years in International Hydrological Program (IHP) basins have been used to determine the statistical factors of the time distribution for rainfalls by the Yen-Chow, Huff, Pilgrim-Cordery and Mononobe models. The Rational, Kajiyama, Nakayasu and Clark model and GIUH model that this study runoff model were used for the purpose of application limit for basin area against design concept by the estimation of flood runoff and the derivation of empirical equations to estimate the parameters for ungaged basins.

• Journal of Korea Port Economic Association
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• v.38 no.3
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• pp.105-131
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• 2022

Even after the improvement in 2019, UNCTAD's Liner Shipping Connectivity Index (LSCI), which evaluates the performance of the global container port market, has limited use. In particular, since the liner shipping connectivity index evaluates the performance based only on the distance of the relationship, the performance index combining the port attractiveness of calling would be more efficient. This study used the modified Huff model, the hub-authority algorithm and the eigenvector centrality of social network analysis, and correlation analysis for 2007, 2017, and 2019 data of Ocean-Commerce, Japan. The findings are as follows: Firstly, the port attractiveness of calling and the overall performance of the port did not always match. However, according to the analysis of the attractiveness of a port calling, Busan remained within the top 10. Still, the attractiveness among other Korean ports improved slowly from the low level during the study period. Secondly, Global container ports are generally specialized for long-term specialized inbound and outbound ports by the route and grow while maintaining professionalism throughout the entire period. The Korean ports continue to change roles from analysis period to period. Lastly, the volume of cargo by period and the extended port connectivity index (EPCI) presented in this study showed a correlation from 0.77 to 0.85. Even though the Atlantic data is excluded from the analysis and the ship's operable capacity is used instead of the port throughput volume, it shows a high correlation. The study result would help evaluate and analyze global ports. According to the study, Korean ports need a long-term strategy to improve performance while maintaining professionalism. In order to maintain and develop the port's desirable role, it is necessary to utilize cooperation and partnerships with the complimentary port and attract shipping companies' services calling to the complementary port. Although this study carried out a complex analysis using a lot of data and methodologies for an extended period, it is necessary to conduct a study covering ports around the world, a long-term panel analysis, and a scientific parameter estimation study of the attractiveness analysis.

• Journal of Korea Water Resources Association
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• v.30 no.2
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• pp.177-191
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• 1997

The influences of the space allocation of design rainfall and partition of the subbasin on the characteristics of urban storm runoff was investigated for the 6 drainage basins by applying SWMM model. It show the deviation of -54.68∼18.77% in the peak discharge when we applied the composed JUFF quantiles to the two zones which are divided by upper and lower region of the basin. Then it is compared with the value for the case of using uniform rainfall distribution all over the drainage. Therefore, it would be helpful to decrease the flood risk when we adopt the space distribution of the design rainfall. The effects of the partitioning the drainage on the computing result shows various responses because of the surface characteristics of the each basin such as slope, imperviousness ratio, buy we can get closer result to the measured value as we make the subbasin detailed. If we use the concept of the skewness and area ratio when we determine the width of subbasin, we can improve the computed result even with fewer number of subbasins. We expect reasonable results which close into the measured results in the range of relative error, 25%, when we divide the basin into more than 3 subbasins and the total urban drainage area is less than 10$\textrm{km}^2$.

• Korean Journal of Hydrosciences
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• v.5
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• pp.33-43
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• 1994

This study is to determine the critical duration of design rainfall and to utilize it for the design of detention pond with pump station. To examine the effect of the duration and temporal distribytion of the design rainfall, Huff's quartile method is used for the 9 cases of durations (ranges from 20 to 240 minutes) with ten years return period, and the ILLUDAS model is used for runoff analysis. The storage ratio, which is the ratio of maximum storage amounts to total runoff volume, is introduced to determine the criticalduration of design rainfall. The duration which maximizes the storage ratio is adopted as the critical duration. This study is applied to 18 urban drainage watercheds with pump station in Seoul, of which the range of watershed area is 0.24~12.70$km^2$. The result of simulation shows that the duration which maximizes storage ratio is 30 and 60 minutes on the whole. It is also shown that the storage ratios of 2nd - and 3rd-quartile pattern are larger than those of 1st- and 4th-quartile pattern of temporal distribution. A simplified empirical formula for Seoul area is suggested by the regression analysis between the maximum storage ratio and the peak ratio. This formula can be utilized for the preliminary design and planning of detention pond with pump station.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.6B
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• pp.503-512
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• 2009

Watershed models, which are a tool for water cycle mechanism, are classified as the distributed model and the lumped model. Currently, the distributed models have been more widely used than lumped model for many researches and applications. The lumped model estimates the parameters in the conceptual and empirical sense, on the other hand, in the case of distributed model the first-guess value is estimated from the grid-based watershed characteristics and rainfall data. Therefore, the distributed model needs more detailed parameter adjustment in its calibration and also one should precisely understand the model parameters' characteristics and sensitivity. This study uses Jungnang basin as a study area and $Vflo^{TM}$ model, which is a physics-based distributed hydrologic model, is used to analyze its parameters' sensitivity. To begin with, 100 years frequency-design rainfall is derived from Huff's method for rainfall duration of 6 hours, then the discharge is simulated using the calibrated parameters of $Vflo^{TM}$ model. As a result, hydraulic conductivity and overland's roughness have an effect on runoff depth and peak discharge, respectively, while channel's roughness have influence on travel time and peak discharge.

• Journal of Distribution Science
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• v.7 no.3
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• pp.5-24
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• 2009

In the retail management, store location has an important influence like business skills. The reason for failure to selecting location is that the market analysis model is not popular in business field. It gets worse in supermarket industry. Currently, store developers are relying on simple statistics and the sixth sense as market analysis techniques. lt proves that the market analysis model is not distributed well in the field. This market analysis model can apply to medium and small business market using an existing market analysis model, broad market model. And its study outcome can be theorized as a result. Converse's new retail model can be used as to analyze junction market. Pareto_Huff model can also be used to compute shopping probability. To do so, this study can be divided into walking distance market and driving distance market as a model market. Also it examines industry type such as SM and SSM. By taking consumer survey, condition of consumers to select store will be counted in shopping probability so that it improves the objectivity and reliability. Through this process, derived study outcome can be a new estimated revenue model for practical application of selecting store location in large and medium-sized supermarket.

• KCID journal
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• v.18 no.2
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• pp.87-100
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• 2011

This study is to delineate the watershed hydrological parameters such as area, slope, rain gauge weight, NRCS-CN and time of concentration (Tc) by using the Geographic Information Sytem (GIS) technique, and estimation of design flood for an ungauged watershed. Especially, we attempted to determine the Tc of ungauged watershed and develop simple program using the cell-based algorithm to calculates upstream or downstream flow time along a flow path for each cell. For a $19km^2$ watershed of tributary of Nakdong river (Seupmoon), the parameters including flow direction, flow accumulation, watershed boundary, stream network and Tc map were extracted from 30m Agreeburn DEM (Digital Elevation Model) and landcover map. And NRCS-CN was extracted from 30m landcover map and soil map. Design rainfall estimation for two rainfall gauge which are Sunsan and Jangcheon using FARD2006 that developed by National Institute for Disaster Prevention (NIDP). Using the parameters as input data of HEC-l model, the design flood was estimated by applying Clark unit hydrograph method. The results showed that the design flood of 50 year frequency of this study was $8m^3/sec$ less than that of the previous fundamental plan in 1994. The value difference came from the different application of watershed parameter, different rainfall distribution (Huff quartile vs. Mononobe) and critical durations. We could infer that the GIS-based parameter preparation is more reasonable than the previous hand-made extraction of watershed parameters.