• Journal of Preventive Medicine and Public Health
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• v.23 no.3 s.31
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• pp.285-295
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• 1990

The utilization of medical care services has been partly regionalized with the implementation of referral requirement by the government since July 1, 1989 when the health insurance coverage was extended to all the people. For the purpose of regionalization, the whole country has been primarily divided into tertiary care regions, and each of them again into secondary care regions. This study investigates the self-sufficiency for in-patient care services of secondary care regions focusing on why it varies among the regions. In doing so, analysis is performed to examine a model which embodies three sets of hypotheses as follows : 1) The regional self-sufficiency for medical care services would be subject to direct influences of regional characteristics, amount of available services and structural properties of regional medical care system ; 2) The regional characteristics would have indirect effects on the self-sufficiency which are mediated by medical care services ; and 3) The amount of available services would indirectly affect the self-sufficiency by influencing the structure of regional medical care system. The results of analysis were generally consistent with the model. The findings have some practical implications. The regional self-sufficiency for medical care services partly depends upon basic properties of each region which cannot be changed in a short period of time. Thus the self-sufficiency for medical care services can be improved mainly by health policy measures. In some of the regions the self-sufficiency for in-patient care services was much higher or lower than can be predicted from the bed-population ratio. Indication is that the allocation of health resources should be made considering a variety of factors bearing upon the supply of and demand for health care ; not on the basis of just a single criterion like the availability. The self-sufficiency of a certain region is related to not only its own characterstics but also the characteristics of neighboring regions. Therefore, attention should be also directed to the inter-regional relationships in health care when the needs for investment of health resources in a region are assessed. However, it should be noted that this study used the data collected before the referral requirement was imposed. A replication of this analysis using recent data would provide an evaluation of the impact on the self-sufficiency of the referral requirement as well as a confirmation of the findings of this study.

• Health Policy and Management
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• v.18 no.4
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• pp.66-84
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• 2008

Objectives: This study aimed to. offer some fundamental evidences for the stroke management policy by investigating the trends of medical care utilization and regionalization in stroke inpatients. Methods: We used the National Health Insurance claims and registry data for stroke inpatients from 1998 to 2005. Among all stroke inpatient claims data, self-employed insured and their dependents were only included in this study. The classification of stroke was based on ICD-10(I60-I69) and its subtype was divided by hemorrhage(I60-I62) and infarction(I63-I64) type. To evaluate regionalization of medical care utilization, relevance index was calculated by regions. The regions were classified 8 large catchment areas and 163 self authorized areas. Results: The overall medical care utilization rate of stroke inpatient has been increased, especially infarction subtype. Among medical care institutions, the utilization of hospital has been the most rapidly increased. Although considered annual rate of interest, total medical cost of stroke inpatients has been increased, Totally, more than 84% of stroke inpatient were admitted to medical care institutions in their own large catchment area during 1998-2005. The relevance indices in their own large catchment area (self sufficiency rates) were more than 70% in most areas regardless of stroke subtype except Chungbuk catchment area. Self sufficiency rates of stroke inpatients among 163 self authorized areas in 1998 and 2005 were 84.2% and 83.1% in metropolitan, 46.7% and 45.5% in urban, and 19.5% and 22.6% in rural areas, respectively. Conclusion: Stroke management policy for improvement of distribution at the district level, especially in rural areas, may be helpful for reducing regional inequality in stroke.

• Journal of Korea Water Resources Association
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• v.48 no.10
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• pp.793-806
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• 2015

The simulation of natural streamflow at ungauged basins is one of the fundamental challenges in hydrology community. The key to runoff simulation in ungauged basins is generally involved with a reliable parameter estimation in a rainfall-runoff model. However, the parameter estimation of the rainfall-runoff model is a complex issue due to an insufficient hydrologic data. This study aims to regionalize the parameters of a continuous rainfall-runoff model in conjunction with a Bayesian statistical technique to consider uncertainty more precisely associated with the parameters. First, this study employed Bayesian Markov Chain Monte Carlo scheme for the estimation of the Sacramento rainfall-runoff model. The Sacramento model is calibrated against observed daily runoff data, and finally, the posterior density function of the parameters is derived. Second, we applied a multiple linear regression model to the set of the parameters with watershed characteristics, to obtain a functional relationship between pairs of variables. The proposed model was also validated with gauged watersheds in accordance with the efficiency criteria such as the Nash-Sutcliffe efficiency, index of agreement and the coefficient of correlation.

• Journal of Korea Water Resources Association
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• v.48 no.6
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• pp.511-522
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• 2015

This study assessed the impact of uncertainties in flood data on the results of flood frequency analysis for Han river basin. To meet this aim, this study quantified assessment focused on the index flood and quantile by regional flood frequency analysis using the flood data from 17 water level gauges in Han river basin. We analysed the results categorized by three cases according to the characteristics of the measured data. Firstly, we analyzed the regional flood frequency for the water level gauge in the Pyungchang river basin to investigate the impact of water level data. The results has the error of 0.240 with respect to the mean flood. Secondly, we examined the impact of uncertainty in measurement data generated by the application of rating on the results of regional flood frequency analysis. We have compared the results by applying the rating estimated for each year to the one by the recently estimated rating. The results showed that the mean error has 0.246 in terms of the mean flood. Finally, we have inferred the regional flood frequency analysis results with the regulated flow in the downstream area of dams. The regulated specific discharge in the downstream area of dams controlled by dam operation showed a large difference to the estimated specific discharge in the downstream area of dams by extension of the natural specific discharge in the upstream area using the regionalization method.

• Journal of Korea Water Resources Association
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• v.40 no.2 s.175
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• pp.147-158
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• 2007

This study attempted to determine a suitable hydrologic model for assessing the impact of climate change on water resources, and to assess the accuracy of streamflow scenarios simulated by the selected hydrologic model using the meteorological scenarios of the Seoul National University Regional Climate Model(SNURCM). Comparison of four water balance models and two daily conceptual rainfall-runoff models for the simulation capability of the Daecheong Dam inflow indicated that the abcd model performs the best among the tested water balance models and performs as well as SSARR that is popular as a daily rainfall-runoff model in Korea. Parameters of the abcd model were then estimated for 12 ungauged subbasins of the Geum River by the regionalization method. The model parameters were first calibrated at nine multi-purpose dams and were then regionalized using catchment characteristics for another four multi-purpose dams, which were assumed to be ungauged sites. The model efficiency(ME) coefficients of the simulated inflows for these four dams were at least 87%. The MEs of the hindcasted meteorological rainfall scenarios of the 12 subbasins of the Geum River were more than 60%. Moreover, the ME of the Daecheong Dam inflow simulated by the abcd model using the SNURCM rainfall scenarios was more than 80%. Therefore, this research concluded that the abcd model coupled with the SNU-RCM meteorological scenarios can be used for impact assessment studies of climate change on water resources.

• Journal of Korea Water Resources Association
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• v.54 no.12
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• pp.1295-1304
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• 2021

For the efficient use and management of water resources, a reliable rainfall-runoff analysis is necessary. Still, continuous hydrological data and rainfall-runoff data are insufficient to secure through measurements and models. In particular, as part of the reasonable improvement of a rainfall-runoff model in the case of an ungauged watershed, regionalization is being used to transfer the parameters necessary for the model application to the ungauged watershed. In this study, the GR4J model was selected, and the SCEM-UA method was used to optimize parameters. The rainfall-runoff model for the analysis of the correlation between watershed characteristics and parameters obtained through the model was regionalized by the Copula function, and rainfall-runoff analysis with the regionalized parameters was performed on the ungauged watershed. In the process, the intermediate state variables of the rainfall-runoff model were extracted, and the correlation analysis between water level and the ground water level was investigated. Furthermore, in the process of rainfall-runoff analysis, the Standardized State variable Drought Index (SSDI) was calculated by calculating and indexing the state variables of the GR4J model. and the calculated SSDI was compared with the standardized Precipitation index (SPI), and the hydrological suitability evaluation of the drought index was performed to confirm the possibility of drought monitoring and application in the ungauged watershed.

• Journal of Korea Water Resources Association
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• v.56 no.9
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• pp.563-574
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• 2023

Recently, climate change has affected functional responses of river basins to meteorological variables, emphasizing the importance of rainfall-runoff simulation research. Simultaneously, the growing interest in machine learning has led to its increased application in hydrological studies. However, it is not yet clear whether machine learning models are more advantageous than the conventional conceptual models. In this study, we compared the performance of the conventional GR6J model with the machine learning-based Random Forest model across 38 basins in Korea using both gauged and ungauged basin prediction methods. For gauged basin predictions, each model was calibrated or trained using observed daily runoff data, and their performance was evaluted over a separate validation period. Subsequently, ungauged basin simulations were evaluated using proximity-based parameter regionalization with Leave-One-Out Cross-Validation (LOOCV). In gauged basins, the Random Forest consistently outperformed the GR6J, exhibiting superiority across basins regardless of whether they had strong or weak rainfall-runoff correlations. This suggest that the inherent data-driven training structures of machine learning models, in contrast to the conceptual models, offer distinct advantages in data-rich scenarios. However, the advantages of the machine-learning algorithm were not replicated in ungauged basin predictions, resulting in a lower performance than that of the GR6J. In conclusion, this study suggests that while the Random Forest model showed enhanced performance in trained locations, the existing GR6J model may be a better choice for prediction in ungagued basins.

• Journal of Preventive Medicine and Public Health
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• v.27 no.4 s.48
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• pp.793-805
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• 1994

Investigating the existence of volume-outcome relationships for specific disease groups relates directly to the policy issue of whether, and how, specific inpatient services should be regionalized. This study examined whether medical costs and lengths of stay as outcomes were affected by changes in volume within hospitals. Based on the claims data obtained from National Federation of Medical Associations, each six disease categories from medical and surgical conditions were selected and 29,720 cases from 1,266 hospitals were analyzed. Main findings of the research can be summarized as follows: 1. Analyzing volume and cost per case relationship, tonsillectomy class 1, hernia procedure class 0, appendectomy and cesarean section class 0,1 in surgical conditions showed negative relationship significantly. In cases of medical conditions, costs per case in respiratory neoplasm class 2, COPD class 1, 2, digestive malignancy were also related to volume negtively. 2. Comparing volume with length of stay per case, lens procedure class 0, hernia procedure class 0, appendectomy class 0,1, cesarean section class 1 in surgical conditions showed negative relationships significantly. In medical conditions, volume of respiratory neoplasm class 2, COPD class 1,2, digestive malignancy class 0 were associated with negatively. 3. Within same disease categories, changes in cost and length of stay per case to volume were more remarkable in severe cases. These results suggested a significant inverse relationship between disease cases and cost, length of stay per case as outcome variables.

• Korean Management Science Review
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• v.11 no.3
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• pp.129-151
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• 1994

This paper focuses on method of setting priorities for telecommunications Standardization in which usually includes prioritization, resource allocation, standardization schedule for each SWA is based on prioritization of SWAs. We mainly used the Analytic Hierarchy Process(AHP) and a modified Delphi technique as a method for planning process. Recently, rapid technology evolution in telecommunications fields increases the necessity of developing more and more new standards. Also increased complexity of technologies makes standards more complicated, more specified and more thick than the past ones. As a result, the number of SWAa(Standardization Work Areas) and SWIs(Standardization Work Iterms) is being increased continuously. Furthermore, rapid telecommunication environment changes such as deregulation, liberalization, privatization, regionalization, and globalization surrounding telecommunications standardization grows increasingly important. To cope with these challenges and to make the more efficient use of the limited standardization resources, i.e., time, financial, personal resources, we will suggest logical and rational approach that is a backbone of strategic plan for telecommunication standardization. The telecommunication standardization planning process involves a MCDM(Multi-Criteria Decision Making) process. The Analytic Hierarchy Process(AHP) is a kind of MCDM approach. Our method is based on a combination of a modified Delphi technique and an application of AHP(spreadsheet model). Analyzed data from Delphi technique is used as inputs to AHP. In addition we also focus on the technique how to combine group judgments and to handle a large number of comparisons.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2001.10a
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• pp.319-323
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• 2001

This study was conducted to derive the regional design rainfall by the regional frequency analysis based on the regionalization of the precipitation. Using the L-moment ratios and Kolmogorov-Smirnov test, the underlying regional probability distribution was identified to be the Generalized extreme value distribution among apt]lied distributions. regional and at-site parameters of the Generalized extreme value distribution were estimated by the method of L-moment. The regional and at-site analysis for the design rainfall were tested by Monte Carlo simulation. Relative root-mean-square error(RRMSE), relative bias(RBIAS) and relative reduction(RR) in RRMSE were computed and compared with those resulting from at-site Monte Carlo simulation. All show that the regional analysis procedure can substantially reduce the RRMSE, RBIAS and RR in RRMSE in the prediction of design rainfall. Consequently, optimal design rainfalls following the regions and consecutive durations were derived by the regional frequency analysis.