• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.6 s.52
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• pp.47-56
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• 2006

A method is presented for evaluating the economic efficiency of a semi-active magneto-rheological (MR) damper system for cable-stayed bridges under earthquake loadings. An optimal MR damper capacity maximizing the cost-effectiveness is estimated for various seismic characteristics of ground motion. The economic efficiency of MR damper system is addressed by introducing the life-cycle cost concept. To evaluate the expected damage cost, the probability of failure is estimated. The cost-effectiveness index is defined as the ratio of the sums of the expected damage costs and each device cost between a bridge structure with the MR damper system and a bridge structure with elastic bearings. In the evaluation of cost-effectiveness, the scale of damage cost is adopted as parametric variables. The results of the evaluation show that the MR damper system can be a cost-effective design alternative. The optical capacity of MR damper is increased as the seismic hazard becomes severe.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.6-6
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• 2018

최근 집중 호우로 인한 내수침수 피해가 도시화와 기후변화로 늘어나고 있다. 내수침수 피해로 인한 복구비용과 시간이 증가하고 있으며 향후에는 이보다 더 크게 늘어날 것으로 예상된다. 이러한 문제를 해결하기 위하여 충분한 선행시간을 가지고 내수 침수 구역을 제시할 수 있어야 한다. 기존의 물리적 모델은 정확하고 정교한 결과를 제공하지만, 시뮬레이션을 준비하고 마치는 데에 시간이 많이 소요된다. 그 이유로서는 강우량, 지형적 특성, 배수관망 시스템, 수문학적 매개변수 등의 다양한 데이터도 필요하기 때문이다. 이는 도시유역에 대한 내수침수의 실시간 예측이 어렵게 되었으며, 충분한 선행시간을 확보하지 못하는 원인이 되었다. 본 연구에서는 이 문제에 대한 해결책으로 결정론적 방법과 확률론적 방법을 자료지향형 모형으로 결합하여 해결책을 제시하고자 하며, 특정 강우 조건하에 도시유역에서의 내수침수에 영향을 미치는 맨홀에 대한 정보를 제공하고자 한다. 위와 같은 과정을 수행하기 위하여 입력자료 조합에 대한 비선형 분석을 실시하였으며, 그 결과로 특정 강우 조건에 대하여 각 맨홀에 대한 누적월류량을 예측할 수 있는 비선형 인공신경망을 구축할 수 있었다. 본 연구에서 제시된 방법론은 국내의 강남 배수분구에 대하여 적용이 되었으며, 내수침수 예측결과와 2차원 해석결과를 비교하고자 하였다. 본 연구에서는 위 과정을 통하여 1차원 도시유출해석을 위한 입력 자료를 준비하는 시간을 절약하고, 다양한 강우 조건과 내수침수지도 사이의 연관성을 학습하는 예측 모형을 이용하여 도시유역의 내수침수에 대한 충분한 선행시간을 확보하고자 한다. 결론적으로, 이 연구의 결과는 도시유역에 대한 비구조적 대책 수립에 도움을 줄 것으로 확인이 되며 도시 유역 내에 맨홀 위치들을 고려한 위험지구를 파악하는 데에 유용할 것으로 판단된다.

• Journal of Labour Economics
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• v.29 no.1
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• pp.41-73
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• 2006

Using 1998~2003 data of the Korea Labor and Income Panel Survey, we analyze the scale, characteristics, and dynamic transition of working poors. The result shows that more than half of the poor families are working poors and that a considerable portion of economically active households is in poverty. However, compare to other kinds of poor families, working poors can easily escape from poverty once after they entered into poverty. When household head is elderly and less educated, the risk of working poor is relatively high. Also, self-employed households have high risk of working poor compare to households having wage worker(s). To ease the problem of working poor, creation of decent jobs and human resource development for vulnerable groups are important. Especially, the creation of decent jobs will do critical roles not only in solving employment issues but also in moderating income inequality among families. Policy development for self-employed in the brink of poverty and establishment of a solid social security system for working poors are also recommended.

• Journal of the Korea Convergence Society
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• v.8 no.10
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• pp.273-279
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• 2017

Purpose: This study was conducted to identify factors associated with cataract and age-related macular degeneration in elders. Methods: In total, 341,588 men(44.18%,) and women(61.887%), aged over 60, were recruited from Korean National Health Insurance Service-Senior(2002-2013). We also analysed the factors which determine the prevalence of contract (ICD-10: H25) and age-related macular degeneration(ICD-10: H353) using Cox proportional hazard regression model Results: The subjects who were women, in older age, the group of higher income level, with hypertension, with heart disease, and with diabetes, the prevalence of both contract and age-related macular were increased(p<0.0001). Conclusion: The prevalence of contract and age-related macular degeneration were higher in old age of Korean who has chronic diseases such as hypertension, heart disease, and diabetes. The management of chronic diseases are essentially required in elderly for more healthy eye in aged society.

• Journal of Korea Water Resources Association
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• v.55 no.9
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• pp.657-668
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• 2022

With the occurrence of localized heavy rain while river flow has increased, both flow and rainfall cause riverside flood damages. As the degree of damage varies according to the level of social and economic impact, it is required to secure sufficient forecast lead time for flood response in areas with high population and asset density. In this study, the author established a flood risk matrix using ensemble rainfall runoff modeling and evaluated its applicability in order to increase the damage reduction effect by securing the time required for flood response. The flood risk matrix constructs the flood damage impact level (X-axis) using flood damage data and predicts the likelihood of flood occurrence (Y-axis) according to the result of ensemble rainfall runoff modeling using LENS rainfall data and as well as probabilistic forecasting. Therefore, the author introduced a method for determining the impact level of flood damage using historical flood damage data and quantitative flood damage assessment methods. It was compared with the existing flood warning data and the damage situation at the flood warning points in the Taehwa River Basin and the Hyeongsan River Basin in the Nakdong River Region. As a result, the analysis showed that it was possible to predict the time and degree of flood risk from up to three days in advance. Hence, it will be helpful for damage reduction activities by securing the lead time for flood response.

• Journal of the Korean Association of Geographic Information Studies
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• v.22 no.4
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• pp.116-130
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• 2019

In South Korea, forest fire occurrences are increasing in size and duration due to various factors such as the increase in fuel materials and frequent drying conditions in forests. Therefore, it is necessary to minimize the damage caused by forest fires by appropriately providing the probability of forest fire risk. The purpose of this study is to improve the Daily Weather Index(DWI) provided by the current forest fire forecasting system in South Korea. A new Fire Risk Index(FRI) is proposed in this study, which is provided in a 5km grid through the synergistic use of numerical weather forecast data, satellite-based drought indices, and forest fire-prone areas. The FRI is calculated based on the product of the Fine Fuel Moisture Code(FFMC) optimized for Korea, an integrated drought index, and spatio-temporal weighting approaches. In order to improve the temporal accuracy of forest fire risk, monthly weights were applied based on the forest fire occurrences by month. Similarly, spatial weights were applied using the forest fire density information to improve the spatial accuracy of forest fire risk. In the time series analysis of the number of monthly forest fires and the FRI, the relationship between the two were well simulated. In addition, it was possible to provide more spatially detailed information on forest fire risk when using FRI in the 5km grid than DWI based on administrative units. The research findings from this study can help make appropriate decisions before and after forest fire occurrences.

• 한국산학경영학회:학술대회논문집
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• 2004.11a
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• pp.73-100
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• 2004

본 연구는 기업은행은 1999년${\sim}$2003년 중소기업 대출 자료로 바젤2 자산상관계수 계산공식의 현실성을 검토하였다. 실증분석 결과에 따르면, 자산상관계수는 매출규모와는 양(+)의 관계를, 신용등급과는 음(-)의 관계를 갖는 것으로 나타나 바젤2 계산공식이 상정하고 있는 자산상관계수 패턴이 국내에서도 현실성이 있었다. 이는 자산상관계수가 매출규모와 음(-)의 관계를 보이는 것으로 보고한 Kim-Park(2004)과 상반되는 결과이다. 또한, 바젤2에서는 60억원 이하의 매출규모에 대해서는 60억원으로 간주하고 있지만, 매출규모 60억원 이하에서도 자산상관계수가 매출규모와 양(+)의 관계를 갖는 것으로 나타났다. 바젤2 계산공식에 의해 산출된 자산상관계수는 자료로 추정한 자산상관계수가 비해 1.3배${\sim}$19.2배 높으며, 이러한 차이는 통계적으로 유의할 뿐 만 아니라 경제적으로도 유의하다. 회귀분석 결과에 의하면, 바젤2 자산상관계수의 상향편의는 주로 계산공식에서 절편을 과도하게 높게 설정하였기 때문에 발생한 것으로 나타났으며, 바젤2에서는 매출규모와 자산상관계수간의 관계를 선형으로 설정하였지만, 로그선형이 실제 자료를 더 잘 적합시키는 것으로 나타났다. 이상의 결과로 보건대, 바젤2의 자산상관계수 계산공식은 비교적 현실적으로 고아된어져 있지만, 국내의 실정에 맞게 조정하기 위해서 보다 광범위한 실증분석이 필요한 것으로 판단된다.

• Korean Journal of Social Welfare
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• v.68 no.2
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• pp.107-130
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• 2016

This study is aimed at the exploratory research on the influence of the obligation of extension of the retirement age on the baby boom generation. The basic question of this study is about which of the baby boom generation can get how much benefit according as the extension of the retirement age becomes compulsory. The extension of the retirement age is the system that can be applied to regular full-time workers. Accordingly, this study is intending to analyze the characteristics of the workers having a high likelihood for benefits from extension of the retirement age by tracing the economic activity state and labor history of the baby boomers. For this purpose, this study looked into the change of the economic activity state by age cohort of the male baby boomers based on the data for the Korea Labor Panel's 4th(2001) & 17th(2014)year. Using Survival analysis, this study also analyzed who will continue to remain as a regular full-time wage earner. As the result of the analysis, it was found that the more the cohort ages of baby boomers increased, the smaller the probability of remaining as a regular full-time wage earner, and the group who can get benefits from extension of the retirement age was predicted to account for only 11.4% level among the baby boomers. In addition, the result showed that there was a high likelihood of getting more benefits from extension of the retirement age when the baby boomers worked for the government-invested institution, corporate bodies, and government organizations rather than working for private enterprises. Thus, it can be safely said that there might appear a generational conflict due to extension of the retirement age in that such jobs coincide with the ones favored by the rising generation.

• Journal of the Korean Data and Information Science Society
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• v.27 no.1
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• pp.1-8
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• 2016

In the recently, violent crime and accidental crime has been generated continuously. Consequently, people anxiety has been heightened. The Closed Circuit Television (CCTV) has been used to ensure the security and evidence for the crimes. However, the video captured from CCTV has being used in the post-processing to apply to the evidence. In this paper, we propose a flexible multi-level models for estimating whether dangerous behavior and the environment and context for pedestrians. The situation analysis builds the knowledge for the pedestrians tracking. Finally, the decision step decides and notifies the threat situation when the behavior observed object is determined to abnormal behavior. Thereby, tracking the behavior of objects in a multi-region, it can be seen that the risk of the object behavior. It can be predicted by the behavior prediction of crime.

• Journal of the military operations research society of Korea
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• v.32 no.1
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• pp.73-89
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• 2006

In this paper, EVMS procedure for KHP program is presented. Research and development of a defense system as a long lead program has a high probability of cost growth due to the uncertainty and risk. Therefore, meeting schedule, technical performance and preventing excessive cost overrun are the main concerning point to successful research and development program. EVMS(Earned Value Management System) is a program management system using earned value to control cost, schedule and technical performance. In order to control cost and schedule and to meet technical performance requirements of the KHP research and development program, it is necessary for us to adapt EVMS to the program.