• The Korean Journal of Health Service Management
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• v.5 no.2
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• pp.77-89
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• 2011

This study conducted a secondary analysis by using original data of performed by Korea Institute for Health and Social Affairs to know factors affecting determinants of health using Lalonde model for the adults aged over 19 years living in Korea. The survey was conducted in 2009 and it evaluated finally 5,867 cases by excluding cases with no answer or a wrong answer. This study model adopted two categories of instrument measure health were objective (Average remaining lifetime) and subjective(EQ-5D) health status. The health determinants included in this study could be divided in to four categories, which were human biology, environment, lifestyle, and health care organization. The results were as follows. In the factors affecting average remaining lifetime, human biology were sex, ages, BMI, showed statistically significant difference, environment category were merry status, education showed statistically significant difference, lifestyle category were exercise, drunks showed statistically significant difference and health care organization category were vaccination, health screening showed statistically significant difference. In the factors affecting EQ-5D, human biology category and health care organization category showed with same average remaining lifetime, environment category were merry status, education, income showed statistically significant difference and lifestyle category were exercise, drunks, stress showed statistically significant difference. The results demonstrated that the best powerful factor was life style category and environment category, the least factor was health care organization category. So lifestyle style and environment category should be considered for the future health plan, budget allocation and the priority in the health care.

• Journal of the Korean Dietetic Association
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• v.25 no.2
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• pp.142-155
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• 2019

The aim of this study was to construct and test a structural equation model for the risk factors of metabolic syndrome in Korean adults. The structural equation model hypothesizes that eating alone and feeling depressed is a risk factor for metabolic syndrome. The data of this study were obtained from the Sixth Korea National Health and Nutrition Examination Survey which was cross-sectional data from the representative national survey. A total of 4,013 subjects replied to the survey item of lifestyle and completed the physical examinations among adults aged 19 years or older in South Korea was in 2015. The structural model in this study was composed of four latent variables: eating alone, depression, negative health behavior, and metabolic syndrome. Two variables, the rate of eating alone and depression, were exogenous variables. Negative health behavior was both a mediating variable and endogenous variable, and metabolic syndrome was the final endogenous variable. The data were analyzed using the Maximum Likelihood method and bootstrapping. The structural model was appropriate for the data based on the model fit indices. The results of this study can be summarized as follows: Eating alone is a direct risk factor of metabolic syndrome in Korean women. Depression can mediate metabolic syndrome through negative health behaviors. Negative health behavior had a direct impact on metabolic syndrome in both men and women. This study may be a guideline for interventions and strategies to reduce the incidence of metabolic syndrome in Korean adults.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.7-13
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• 2018

The strength of concrete is affected significantly not only by the internal influence factors of cement, water, sand, aggregate, and admixture, but also by the external influence factors of concrete placement delay and curing temperature. The objective of this research was to predict the concrete strength considering both the internal and external influence factors when concrete is placed at the construction site. In this study, a concrete strength test was conducted on the 24 combinations of internal and external influence factors, and a neural network model was constructed using the test data. This neural network model can predict the concrete strength considering the external influence factors of the concrete placement delay and curing temperature when concrete is placed at the construction site. Contractors can use the concrete strength prediction neural network model to make concrete more robust to external influence factors during concrete placement at a construction site.

• Journal of the Korea Institute of Building Construction
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• v.21 no.5
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• pp.495-506
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• 2021

A Conceptual cost estimate, which is computed in the preliminary step of a project, is important for decision-making by a contractor in terms of the project budget, economic feasibility and validity analysis, and alternative comparisons. Therefore, a high error rate of a prediction model for a conceptual cost estimate can lead to various problems including excessive project expenditures and a delayed break-even point. this study proposed optimal impact factors by configuring quantitative impact factors computable in a preliminary step in various cases(combinations of impact factors). subsequently, the accuracy of different cases was comparatively analyzed by using the cases as input values of a prediction model using regression analysis. when the optimal combination of impact factors proposed in this study and other combination of impact factors were applied to the prediction model, the regression analysis-based prediction model exhibited 0.2-4.7% improvements in accuracy, respectively. the optimal combination of impact factors proposed in this study improved the accuracy of the prediction model of a conceptual cost estimate by removing unnecessary impact factor.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.34 no.6
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• pp.3-14
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• 2018

The aim of this study is to propose a method for calculating the weight of walking energy in ERAM model by calculating it for the analysis of vertical and horizontal spaces in a building. Conventional theories on the space analysis in the field of architectural planning predict the pedestrian volume of network spaces in urban street or in two-dimensional plane within a building, however, for vertical and horizontal spaces in a building, estimates of the pedestrian volume by those theories are limited. Because in the spatial syntax and ERAM model have been applied weights such as the spatial depth, adjacent angles, and physical distances available only to the two-dimensional same layer or plane. Therefore, the following basic assumptions and analysis conditions in this study were established for deriving a predictor of pedestrian volume in vertical and horizontal spaces of a building. The basic premise of space analysis is not to address the relationship between the pedestrian volume and the spatial structure itself but to the properties of spatial structure connection that human beings experience. The analysis conditions in three-dimensional spaces are as follows : 1) Measurement units should be standardized on the same scale, and 2) The connection characteristics between spaces should influence the accessibility of human beings. In this regard, a factor of walking energy has the attributes to analyze the connection of vertical and horizontal spaces and satisfies the analysis conditions presented in this study. This study has two implications. First, this study has shown how to quantitatively calculate the walking energy after a factor of walking energy was derived to predict the pedestrian volume in vertical and horizontal spaces. Second, the method of calculating the walking energy can be applied to the weights of the ERAM model, which provided the theoretical basis for future studies to predict the pedestrian volume of vertical and horizontal spaces in a building.

• International Area Studies Review
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• v.13 no.2
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• pp.505-523
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• 2009

We study the cost of capital of Islamic enterprise using the Capital Asset Pricing Model(CAPM). When there exists no risk-free interest rate, the security market line(SML) of Islamic enterprise shows an upward slope starting from the origin. The slope is bigger than that of SML with risk-free interest rate. This is because the cost of capital of Islamic enterprise is higher than that of western firms for the same level of systematic risk. When the effect of zakat is considered, the risk-free interest rate is replaced by minimum required rate of return. The SML of Islamic enterprise reveals an upward slope but it does not pass through the origin. This is because Islamic enterprise cannot invest on risk-free asset. In order to overcome the theoretic limits of CAPM, we propose to use multi-factor approach such as arbitrage pricing model instead of single-factor model for future study.

• Journal of Ocean Engineering and Technology
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• v.36 no.1
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• pp.1-10
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• 2022

Recently, as the offshore structures are operated in the deep-sea oil fields, interest in the analysis of relative wave elevation around platforms is increased. In this study, it is examined how the analysis results differ depending on the characteristics of the wave probe when interpreting the relative wave elevation in the model test. First, by conducting the wave probe comparison experiment in the two-dimensional wave tank, it is confirmed how the measured values differ according to the type of wave probe for the same physical phenomenon. Two types of wave probe are selected, the resistance type and the capacitance type, and the causes of the difference in measured values is studied. After that, the model test of the semi-submersible platform is conducted to investigate the relative wave elevation. Relative wave elevation is measured with the wave probes used in the wave probe comparison experiment and analyzed to estimate the asymmetric factor and the extreme upwell. The results between the two types of wave probes are compared, and qualitative study for the cause of the difference is conducted by photographing the physical phenomenon using a high-speed camera. Through the above study, it is confirmed that the capacitance type wave probe shows a larger measured value than the resistance type under the breaking-wave condition, and the same results are obtained for the asymmetric factor and the extreme upwell. These results is thought to be due to the difference in the measurement principle between wave probes, which is whether or not they measured water bubbles. This implies that the model test should be conducted using appropriate wave probes by considering the physical phenomenon to be analyzed.

• Progress in Medical Physics
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• v.32 no.4
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• pp.137-144
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• 2021

Purpose: This study aimed to investigate the accuracy of head scatter factor (S_c) by applying a developed multi-leaf collimator (MLC) scatter source model for an unflattened photon beam. Methods: Sets of S_c values were measured for various jaw-defined square and rectangular fields and MLC-defined square fields for developing dual-source model (DSM) and MLC scatter model. A 6 MV unflattened photon beam has been used. Measurements were performed using a 0.125 cm³ cylindrical ionization chamber and a mini phantom. Then, the parameters of both models have been optimized, and S_c has been calculated. The DSM and MLC scatter models have been verified by comparing the calculated values to the three S_c set measurement values of the jaw-defined field and the two S_c set measurement values of MLC-defined fields used in the existing modeling, respectively. Results: For jaw-defined fields, the calculated S_c using the DSM was consistent with the measured S_c value. This demonstrates that the DSM was properly optimized and modeled for the measured values. For the MLC-defined fields, the accuracy between the calculated and measured S_c values with the addition of the MLC scatter source appeared to be high, but the only use of the DSM resulted in a significantly bigger differences. Conclusions: Both the DSM and MLC models could also be applied to an unflattened beam. When considering scattered radiation from the MLC by adding an MLC scatter source model, it showed a higher degree of agreement with the actual measured S_c value than when using only DSM in the same way as in previous studies.

• Journal of Korean Society for Quality Management
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• v.50 no.1
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• pp.125-138
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• 2022

Purpose: Failure Mode and Effect Analysis (FMEA) is a widely utilized technique to measure product reliability by identifying potential failure modes. Even though FMEA techniques have been studied, the form of Risk Priority Number (RPN) used to evaluate risk priority in FMEA is still questionable because of its shortcomings. In this study, we suggest common RPN(cRPN) to resolve shortcomings of the traditional RPN and show the extensibility of cRPN. Methods: We suggest cRPN which is based on Cobb-Douglas production function, and represent the various application on weighting risk factors, weighted RPN in a mathematical way, and show the possibility of statistical approach. We also conduct numerical study to examine the difference of the traditional RPN and cRPN as well as the potential application from the analysis on marginal effects of each risk factor. Results: cRPN successfully integrates previously suggested approaches especially on the relative importance of risk factors and weighting RPN. Moreover, we analyze the effect of corrective actions in terms of econometric analysis using cRPN. Since cRPN is rely on the reliable mathematical model, there would be numerous applications using cRPN such as smart factory based on A.I. techniques. Conclusion: We propose a reliable mathematical model of RPN based on Cobb-Douglas production function. Our suggested model, cRPN, resolves various shortcomings such as consideration of the relative importance, the effect of combinations among risk factors. In addition, by adopting a reliable mathematical model, quantitative approaches are expected to be applied using cRPN. We find that cRPN can be utilized to the field of industry because it is able to be applied without modifying the entire systems or the conventional actions.

• Journal of the Korean Geotechnical Society
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• v.19 no.6
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• pp.151-160
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• 2003

The stability of the designed rock slope is analysed based on two kinds of shear strength model. Besides the deterministic analysis, a probabilistic approach on Monte Carlo simulation is proposed to deal with the uncertain characteristics of the discontinuity and the results obtained from two models are compared to each other. To carry out the research of characteristics of the discontinuity, BIPS, DOM Scanline survey data and direct shear test data are used, and chi-square test is used for determining the probability distribution function. The rock slope is evaluated to be stable in the deterministic analysis, but in the probabilistic analysis, the probability of failure is more than 5%, so, it is considered that the rock slope is unstable. In the shear strength models, the probability of the failure based on the Mohr-Coulomb model(linear model) is higher than that of the Barton model. It is supported by the fact that the Mohr-Coulomb model is more sensitive to block size than the Barton model. In fact, there is no reliable way to estimate the unit cohesion of the Mohr-Coulomb model except f3r back analysis and in the case of small block failure in the slope, Mohr-Coulomb model may excessively evaluate the factor of the safety. So, the Barton model of which parameters are easily acquired using the geological survey is more reasonable for the stability of the studied slope. Also, the selection of the proper shear strength model is an important factor for slope failure analysis.