• Clinical and Experimental Pediatrics
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• v.51 no.9
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• pp.977-986
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• 2008

Purpose : This study aims to estimate the financial cost of rotavirus infection in Korea in the year of 2005. Methods : The incidence rates used were from the epidemiological profile at Jeoungeub District (5.8 cases/1,000 children <5 years old for inpatients, and 22.65 cases/1,000 children <5 years old for outpatients, per year). The health care cost per capita of rotavirus infection (ICD code: A08.0) was extracted from the Health Insurance Review and Assessment Service database in Korea. The patient survey was conducted to capture information about non-medical costs and associated productivity loss incurred by adult caregivers. Results : The number of annual national cases among children <5 years old with rotavirus infection was estimated to be 69,122 (i.e., 55,030 outpatients and 14,092 inpatients). The total cost of rotavirus infection was estimated at 13.3 billion Korean won, comprising 11 billion Korean won (82.7%) of direct medical costs, 1.6 billion Korean won (12.0%) of direct non-medical costs (e.g., transportation and supplies), and 0.68 billion Korean won (5.1%) of productivity lost by adult caregivers. Conclusion : Rotavirus infection carries not only medical costs but also non-medical and indirect costs; together, these costs incur a significant burden on South Korean society. The impact of rotavirus on quality of life and health among patient caregivers was not considered in this study, but it does merit further research.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.28 no.4
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• pp.191-201
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• 2016

A stochastic process has been used to develop a condition-based model for preventive maintenance of armor units of rubble-mound breakwaters that can make a decision the optimal interval at which some repair actions should be performed under the perfect maintenance. The proposed cost model in this paper based on renewal reward process can take account of the interest rate, also consider the unplanned maintenance cost which has been treated like a constant in the previous studies to be a time-dependent random variable. A function for the unplanned maintenance cost has been mathematically proposed so that the cumulative damage, serviceability limit and importance of structure can be taken into account, by which a age-based maintenance can be extended to a condition-based maintenance straightforwardly. The coefficients involved in the function can also be properly estimated using a method expressed in this paper. Two stochastic processes, Wiener process and gamma process have been applied to armor stones of rubble-mound breakwaters. By evaluating the expected total cost rate as a function of time for various serviceability limits, interest rates and importances of structure, the optimal period of preventive maintenance can easily determined through the minimization of the expected total cost rate. For a fixed serviceability limit, it shows that the optimal period has been delayed while the interest rate increases, so that the expected total cost rate has become lower. In addition, the gamma process tends to estimate the optimal period more conservatively than the Wiener process. Finally, it is found that the more crucial the level of importance of structure becomes, the more often preventive maintenances should be carried out.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.2B
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• pp.199-213
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• 2008

The goal of this research is to develop and apply the integrational operation method (IOM) for the modeling of the monthly pan evaporation (PE) and the alfalfa reference evapotranspiration ($ET_r$). Since the observed data of the alfalfa $ET_r$ using lysimeter have not been measured for a long time in Republic of Korea, Penman-Monteith (PM) method is used to estimate the observed alfalfa $ET_r$. The IOM consists of the application of the stochastic and neural networks models, respectively. The stochastic model is applied to generate the training dataset for the monthly PE and the alfalfa $ET_r$, and the neural networks models are applied to calculate the observed test dataset reasonably. Among the considered six training patterns, 1,000/PARMA(1,1)/GRNNM-GA training pattern can evaluate the suggested climatic variables very well and also construct the reliable data for the monthly PE and the alfalfa $ET_r$. Uncertainty analysis is used to eliminate the climatic variables of input nodes from 1,000/PARMA(1,1)/GRNNM-GA training pattern. The sensitive and insensitive climatic variables are chosen from the uncertainty analysis of the input nodes. Finally, it can be to model the monthly PE and the alfalfa $ET_r$ simultaneously with the least cost and endeavor using the IOM.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.1
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• pp.231-243
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• 1994

A stochastic programming model for river water quality management was developed. River water quality, river flow, quality and flowrate of the wastewater treatment plant inflow were treated as random variables in the model. Withdrawal for water supply and submerged weir reaeration were included in the model itself. A probabilistic model was formulated to compute the expectation and variance of water quality using Streeter-Phelps equation. Chance constraints of the optimization problem were converted to deterministic equivalents by chance constrained method. Objective function was total annual treatment cost of all wastewater treatment plants in the region. Construction cost function and O & M cost function were derived in the form of nonlinear equations that are functions of treatment efficiency and capacity of treatment plant. The optimization problem was solved by nonlinear programming. This model was applied to the lower Han River. The results show that the reliability to meet the DO standards of the year 1996 is about 50% when the treatment level of four wastewater treatment plants in Seoul is secondary treatment, and BOD load from the tributary inflows is the same as present time. And when BOD load from Tanchon, Jungrangchon, and Anyangchon is decreased to 50%, the reliability to meet the DO standards of the year 1996 is above 60%. This results indicated that for the sake of the water quality conservation of the lower Han River, water quality of the tributaries must be improved, and at least secondary level of treatment is required in the wastewater treatment plants.

• The Journal of the Korea Contents Association
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• v.22 no.2
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• pp.782-793
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• 2022

The rise in chronic disease not only has a negative effect on people's lives, but it also increases the cost of medical care owing to the increased usage of medical care as health and medical technology improves, life expectancy rises, and rapid population ageing. In such context, this study examined the difference in the disease cost of hypertension according to demographic information and the effect of the initial diagnosis age and treatment period on the cost. This study used the Korean Health Panel Survey from 2010 to 2017, and selected subjects based on health insurance beneficiaries between the ages of 30 and under 80. With the selected data, the direct and indirect costs of disease loss were calculated according to the cost of illness approach, and we constructed a disease-loss ratio cohort considering the age of diagnosis and time of treatment for hypertension. From the results of the study, the annual cost of disease loss for hypertensive patients differed by gender by 110,107 won, and it was found that the cost increased by 1.8 times as the treatment time increased. In addition, when comparing disease loss ratios between the same age groups, it was found that the disease loss ratios between those in their 60s and 70s were affected by treatment time. This study confirmed that hypertension significantly affects the cost of the disease, and not only requires early diagnosis and management, but also preventive efforts to lower the incidence of hypertensive disease must be strengthened.

• KIEAE Journal
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• v.16 no.3
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• pp.137-143
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• 2016

Purpose: Apartment housing should conduct a cyclic repair to keep and maintain the building performance since they are constructed. Therefore, the repair plan would be provided for long term period which explains the repair time, items and repair cost. Residents of apartment housing are responsible to pay for the repair activities. For repair cost, residents would reserve the money for repair little by little continuously until the required repair time because the repair cost takes a big burden for residents and lots of money a time. But, there is no systematic approach to provide the long term repair cost because it is no proper forecast of the repair cost to the upcoming repair time. In this study, it aimed at providing the monthly accumulation of the long term repair cost with the survey data in Seoul. Method: For these, the surveyed data are classified into 6 categories and number of data are 1,918. In addition, it developed the repair cost model for the 24 repair works and the cumulation function which is reflected with the each cost model. Result: This study are shown as follows : First, among the various estimation for the repair cost, the power function has a goodness of fit in statistics. Second, the monthly accumulation would be 12,840 won/household in size of $100,000m^2$ management area and $81.7won/m^2$ in size of the 1,000 household number during 40 years.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.11a
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• pp.4.2-4.2
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• 2009

10년 후면 영어와 한국어가 실시간으로 자동 통역되는 통역기가등장하며, 컴퓨터의 키보드 나 마우스 등은 음성으로 대체되며, 인간과대화를 나누는 로봇이 등장하여 대부분의 인간 허드렛일을 대행 할 것으로 예상된다. 이러한 인공 지능형기기를 구현하기 위해서는 현재보다 1천배 이상의 성능을 보이는 즉, 테라급의 CPU와 메모리가 필요하다. 현재 반도체소자의 주류를 이루고 있는실리콘 트랜지스터는 무어 법칙에 따라 매18개월마다 2 배씩트랜지스터 집적도가 증가되어 왔으며 현재 32nm가 시장 출시를 앞두고 있으나 2016년 이후 22nm 이하는 특성 불균일/열 발생 과 같은 기술적 한계와 천문학적으로 늘어나는 칩 제조비용 때문에 제품 출시가 매우 어려울 것으로 여겨진다. 교육과학기술부는 이러한 한계 극복을 위해 21세기 Frontier 프로그램으로 테라급나노소자개발사업단을 2000년 7월 발족 하였으며 본 사업단은 테라급의 성능과 메모리 집적도를 갖는 나노소자개발을 최종목표로 출범 하였다. 프론티어사업은 10년 이상의 장기적인 개발기간이 필요한 'High Risk, High Return'의 특성을 갖고 있다. 본사업단은 이러한 프론티어사업의 취지에 따라 철저한 사전기획과 기술 환경변화에 따른 신속한 대응력, 철저한현장 중심적 사업관리를 해왔다. 본 재료학회 추계학술대회에서는 본 사업단이 이룩한 성과와 미래의 나노소자들을 소개할 예정이다.

• Journal of Preventive Medicine and Public Health
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• v.39 no.6
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• pp.499-504
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• 2006

Objectives : The aim of the study was to estimate the annual socioeconomic cost of diseases in Korea. Methods : We estimate both the direct and indirect costs of diseases in Korea during 2003 using a prevalence-based approach. The direct cost estimates included medical expenditures, traffic costs and caregiver's cost, and the indirect costs, representing the loss of production, included lost workdays due to illness and lost earnings due to premature death, which were estimated based on the human capital theory. The cost estimates were reported at three different discount rates (0, 3 and 5%). Results : The cost of diseases in Korea during 2003 was 38.4 trillion won based on 0% discount rate. This estimate represents approximately 5.3% of GDP The direct and indirect costs were estimated to be 22.5 trillion (58.5% of total cost) and 15.9 trillion won (41.5%), respectively. It was also found that the cost for those aged $40\sim49$ accounted for the largest proportion (21.7%) in relation to age groups. The cost of diseases for males was 23.5% higher than that for females. For major diseases, the total socioeconomic costs were 16.0, 13.4, 11.3 and 11.19% for neoplasms, and diseases of the digestive, respiratory and circulatory systems, respectively. Conclusions : This study can be expected to provide valuable information for determining intervention and funding priorities, and for planning health policies.

• Journal of Preventive Medicine and Public Health
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• v.43 no.4
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• pp.341-351
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• 2010

The purpose of this study was to estimate the socioeconomic costs resulting from alcohol drinking among adolescents as of 2006 from a societal perspective. Methods: The costs were classified into direct costs, indirect costs, and other costs. The direct costs consisted of direct medical costs and direct non-medical costs. The indirect costs were computed by future income losses from premature death, productivity losses from using medical services and reduction of productivity from drinking and hangover. The other costs consisted of property damage, public administrative expenses, and traffic accident compensation. Results: The socioeconomic costs of alcohol drinking among adolescents as of 2006 were estimated to be 387.5 billion won (0.05% of GDP). In the case of the former, the amount included 48.25% for reduction of productivity from drinking and hangover, 39.38% for future income losses from premature death, and 6.71% for hangover costs. Conclusions: The results showed that the socioeconomic costs of alcohol drinking among adolescents in Korea were a serious as compared with that of the United States. Therefore, the active interventions such as a surveillance system and a prevention program to control adolescents drinking by government and preventive medicine specialist are needed.

• Journal of Korea Water Resources Association
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• v.31 no.1
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• pp.59-69
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• 1998

A regression model with basin physiographic characteristics as independent variables was calibrated for regional flood frequency analysis. In case that high correlations existing among the independent variables the ridge regression has been known to have capability of overcoming the problems of multicollinearity. To optimize the ridge regression model the cost function including regularization parameter must be minimized. In this research the genetic algorithm was applied on this optimization problem. The genetic algorithm is a stochastic search method that mimic the metaphor of natural biological heredity. Using this method the regression model could have optimized and stable weights of variables.