• Journal of the Korean Geotechnical Society
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• v.34 no.6
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• pp.25-36
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• 2018

Soil liquefaction is one of the types of major seismic damage. Soil liquefaction is a phenomenon that can cause enormous human and economic damages, and it must be examined before designing geotechnical structures. In this study, we proposed a practical method of developing a multi-hazard fragility surface for liquefaction of levee considering earthquake magnitude and water level. Limit state for liquefaction of levee was defined by liquefaction potential index (LPI), which is frequently used to assess the liquefaction susceptibility of soils. In order to consider the uncertainty of soil properties, Monte Carlo Simulation based probabilistic analysis was performed. Based on the analysis results, a 3D fragility surface representing the probability of failure by soil liquefaction as a function of the ground motion and water level has been established. The prepared multi-hazard fragility surface can be used to evaluate the safety of levees against liquefaction and to assess the risk in earthquake and flood prone areas.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.5
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• pp.325-331
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• 2016

This research developed a flood fragility curve of bridges considering the debris impacts. Damage and failures of civil infrastructure due to natural disasters can cause casualties as well as social and economic losses. Fragility analysis is an effective tool to help better understand the vulnerability of a structure to possible extreme events, such as earthquakes and floods. In particular, flood-induced failures of bridges are relatively common in Korea, because of the mountainous regions and summer concentrated rainfall. The main failure reasons during floods are reported to be debris impact and scour; however, research regarding debris impacts is considered challenging due to various uncertainties that affect the failure probability. This study introduces a fragility analysis methodology for evaluating the structural vulnerability due to debris impacts during floods. The proposed method describes how the essential components in fragility analysis are considered, including limit-state function, intensity measure of the debris impact, and finite element model. A numerical example of the proposed fragility analysis is presented using a bridge pier system under a debris impact.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.431-431
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• 2021

4차 산업혁명의 도래로 사회기반시설물의 계획 및 운영관리에 있어 데이터 분석을 통한 가치추출에 대한 관심은 매우 높은 상황이다. 데이터의 가용성과 접근성, 정부 지원 등을 평가하는 공공데이터 개방지수에서 한국은 1점 만점에 0.93점을 획득하여 경제협력개발기구 회원국 중 1위(2019년 기준)를 할 정도로 매우 높은 수준(평균 0.60점)이다. 그러나 공식적으로 발표 및 배포되는 사회기반시설물 관련 정보와 심도 있는 연구 분석이 필요한 정보는 접근이 여전히 제한적이라 할 수 있다. 특히 대표적인 사회기반시설물인 상수도시스템은 대부분 국가중요시설로 지정되어 있어 다양한 정보를 획득하고 분석하는데 제약이 존재하며, 관련 국가통계인 상수도통계에서는 누수사고 등과 같은 비정상적 상황에 대한 사고지점, 원인 등과 같은 세부정보는 제공하고 있지 않다. 본 연구에서는 웹크롤링 및 빅데이터 분석기술을 활용하여 과거 일정기간 발생한 지자체의 상수도 누수사고 관련 뉴스를 전수조사하고 도출된 사고건수를 국가 공인 정보인 상수도통계자료와 비교·분석하였다. 독립적인 누수사고 기사를 추출하기 위해서 중복기사의 제거, 누수 관련 키워드 정립, 상수도분야 이외의 관련기사 제거 등의 절차가 필요하며, 이와 같은 기법은 R프로그래밍을 통해 구현되었다. 추가적으로 뉴스기사의 자연어 처리기반 정보추출기법을 통해 누수사고 건수 뿐만 아니라 사고발생일, 위치, 원인, 피해정도, 그리고 대상 관로의 크기 등을 획득하여 상수도 통계에서 제시하고 있는 정보보다 많은 가치를 추출하여 연계할 수 있는 방안을 제시하였다. 제시된 방법론을 국내 A광역시에 적용하여 누수사고 건수를 비교한 결과 상수도통계에서 제시하고 있는 누수발생건수와 유사한 규모의 사고건수를 뉴스기사분석을 통해 도출할 수 있었다. 제안된 방법론은 추가적인 정보의 추출이 가능하다는 점에서 향후 활용성이 높을 것으로 기대된다.

• Journal of agricultural medicine and community health
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• v.39 no.4
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• pp.240-255
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• 2014

Objective: The purpose of this study was to identify the correlates of bone mineral density of Korean adults. Methods: This study was based on the data from the 2010-2011 Korean National Health and Nutrition Examination Survey (KNHANES, 2010~2011) V. Among 8,473 subjects of the survey, who were adults 19 years old or over with bone mineral density data, the current study excluded those whose data include a missing study variable or the response of 'I don't know', and finally analyzed the data of 5,986 subjects (2,692 males and 3,294 females). This study employed the following statistical methods of analysis: t-test, analysis of variance (ANOVA), and hierarchical multivariate linear regression analysis. Results: In multivariate analysis, in the case of men, the significant associated factors in bone mineral density were age, education level, body mass index (BMI), waist circumference, total muscle mass, exercise, and weight control; in the case of women, the significant associated factors in bone mineral density were age, education level, economic activity, BMI, total muscle mass, exercise, weight control. fat intake, uptake female hormone, menopause, and age of menarche. Conclusion: For both sexes, the strongest modifiable factor in influencing bone mineral density was total muscle mass. Therefore, to prevent osteoporosis and promote health, active health education and interventions such as regular exercise for total muscle mass increase should be implemented from an early growth period.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.11
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• pp.884-891
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• 2020

The collapse of bridges can cause massive casualties and economic losses. Therefore, it is thus essential to evaluate the structural safety of bridges. For this task, structural reliability analysis, considering various bridge-related uncertainty factors, is often used. This paper proposes a new computational platform to perform structural reliability analysis for bridges and evaluate their structural safety under various loading conditions. For this purpose, a software package of reliability analysis, Finite Element Reliability Using MATLAB (FERUM), was integrated with MIDAS/CIVIL, which is a widely-used commercial software package specialized for bridges. Furthermore, a graphical user interface (GUI) control module has been added to FERUM to overcome the limitations of software operation. In this study, the proposed platform was applied to a simple frame structure, and the analysis results of the FORM (First-Order Reliability Method) and MCS (Monte Carlo simulation), which are representative reliability analysis methods, were compared. The proposed platform was verified by confirming that the calculated failure probability difference was less than 5%. In addition, the structural safety of a pre-stressed concrete (PSC) bridge was evaluated considering the KL-510 vehicle model. The proposed new structural reliability analysis platform is expected to enable an effective reliability-based safety evaluation of bridges.

• Journal of the Korean GEO-environmental Society
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• v.13 no.1
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• pp.31-36
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• 2012

Recently, industrial by-products are exponentially growing because energy consumption is increasing due to rapid industrial development and improved living standards. The purpose of this study is to determine the proper mixing ratio to meet the liner conditions(must be less than $1{\times}10^{-7}$cm/sec), using pond ash and bentonite as liner. As the result of the compaction test, depending on the increase mixing ratio of bentonite, the maximum dry unit weight was decreased but the optimum moisture content was tended to be increased at the compaction curve. As the result of the permeability test, depending on the increase mixing ratio of bentonite, the coefficient of permeability showed tendency to be decreased in the form of index and the tendency was caused by the hydration reactions filling the void of the pond ash. When the mixing ratio of bentonite was approximately over 15%, it was satisfied with the land fill liner conditions. In other words, it is necessary to consider other mixtures containing the cement or another material in the economical aspect for application of the pond ash.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.12
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• pp.371-380
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• 2016

The purpose of this study was to investigate the caregiving stress and depression of spouses who support adults with physical disabilities, calculate the activity of daily living (ADL) of the disabled and determine the correlation of each area and the influence of their ADL on the caregiving stress and depression of spouses. This study was performed on 86 spouses of the disabled who were receiving rehabilitation treatment in two hospitals located in S and K cities from July to August 2016. According to the results, the total caregiving stress scores were $71.43{\pm}17.78$ and the economic and psychological stresses among low items were higher than the other items. The total depression score was $50.34{\pm}26.41$, which was slightly higher than the average of normal adults. The caregiving stress and depression were high for aged women, for cases of high caregiving expense and time, for young disabled and for stroke disease. Factors that affected the caregiving stress were the age of the disabled and the duration of their disability; their ADL had no influence on the caregiving stress. The result showed that the depression affected their age, disabled type and grade, and ADL. Actual policy support capable of giving economic, physical, and psychological assistance should be prepared to reduce caregiving stress and depression.

• Korean Journal of Social Welfare
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• v.38
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• pp.309-335
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• 1999

The purpose of this study is to classify welfare regimes using the method of qualitative comparative analysis(QCA). By formalizing the logic of qualitative analysis, QCA makes it possible to bring the logic and empirical intensity of qualitative approaches to studies that normally call for the use of quantitative methods. In QCA each case is conceived holistically, as a configuration of conditions, not a collection of scores on variables. Major findings of this study are as follows. Firstly, major explanations for welfare state differences are partly supported. Indicators relevant to each explanation can appear to be important only if other causal conditions are considered. For example, in the interventionist welfare states, high GDP per capita must be combined with the weakness of the Right and ethnic homogeneity. Otherwise, it can't discern interventionist from liberalist welfare states. Secondly, the equation for the interventionist welfare states includes multiple causal conjunctures. Many studies of welfare state find the same results. The third main finding is that IDV(individualism index) which is proxy for the weakness of informal network matters. Combining with other variables, IDV seems to be important in explaining the emergence of Confucian welfare states.

• Journal of the Korean Institute of Intelligent Systems
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• v.9 no.4
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• pp.420-425
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• 1999

The maximum demand controller is an electrical equipment installed at the consumer side of power system for monitoring the electrical energy consumed during every integrating period and preventing the target maximum demand (MD) being exceeded by disconnecting sheddable loads. By avoiding the peak loads and spreading the energy requirement the controller contributes to maximizing the utility factor of the generator systems. It results in not only saving the energy but also reducing the budget for constructing the natural base facilities by keeping thc number of generating plants ~ninimumT. he conventional MD controllers often bring about the large number of control actions during the every inteyating period and/or undesirable loaddisconnecting operations during the beginning stage of the integrating period. These make the users aviod the MD controllers. In this paper. fuzzy control technique is used to get around the disadvantages of the conventional MD control system. The proposed MD controller consists of the predictor module and the fuzzy MD control module. The proposed forecasting method uses the SOFM neural network model, differently from time series analysis, and thus it has inherent advantages of neural network such as parallel processing, generalization and robustness. The MD fuzzy controller determines the sensitivity of control action based on the time closed to the end of the integrating period and the urgency of the load interrupting action along the predicted demand reaching the target. The experimental results show that the proposed method has more accurate forecastinglcontrol performance than the previous methods.

• Journal of Korea Port Economic Association
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• v.38 no.4
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• pp.139-169
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• 2022

This study derived determinants of 'Decent Work' in the logistics industry and aims to use the analysis results as basic data for policymaking related to labor in the logistics industry and to prepare policies suitable for the characteristics of the logistics industry. As the dependent variable of the model, the Decent Job derived from the first study was used, and the target model was derived from panel data of whole industries to understand the unique characteristics of logistics industry jobs and applied to the logistics industry model. This study found that in the logistics industry, developing the expertise of the logistics industry through "vocational training" compared to whole industries is an important factor rather than raising the "academic level" through the regular curriculum. This seems to reflect the characteristics of the logistics industry as specialized vocational training is required in the case of "railway transportation", "inland water and port transportation", and "air cargo transportation", which have a high proportion of decent job workers among the detailed logistics industries analyzed in this study. Therefore, developing job expertise through additional manpower training programs such as vocational training as well as academic fields learned through regular curriculum is a very important factor in engaging in "Decent Work" not only in the logistics industry but also in other industries.