• Proceedings of the Computational Structural Engineering Institute Conference
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• 1998.10a
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• pp.151-158
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• 1998

This paper presents an optimal decision model for minimizing the life-cycle cost of steel box girder bridges. The point is that it takes into account service life process as a whole, and the life-cycle costs include initial (design, testing, and construction) costs, maintenance costs and expected failure costs. The problem is formulated as that of minimization of expected total life-cycle cost with respect to the design variables. The optimal solution identifies those values of the decision variables that result in minimum expected total cost. The performance constraints in the form of flexural failure and shear failure are those specified in the design code. Based on extensive numerical investigations, it may be positively stated that the optimum design of steel box girder bridges based on life-cycle cost approach proposed in this study provides a lot more rational and economical design, and thus the proposed approach will propose the development of new concepts and design methodologies that may have important implications in the next generation performance-based design codes and standards.

• Journal of Families and Better Life
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• v.23 no.3 s.75
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• pp.217-230
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• 2005

The purpose of this study was to examine factors related to the purchase of cash-value life insurance of households. Based on human capital and bequest motive theories of the demand for life insurance, this study developed a conceptual model of the demand for life insurance of households. In addition, in order to capture the beneficiaries' preference and expected lifetime utility, expected future financial needs were included in the conceptual model. Using Heckit analysis, the model was estimated by two stages. The results supported that human capital, bequest motives and expected future financial needs were significant factors on both decision to have insurance and the mont of insurance. Specifically, if the household's head expected to have a higher potential in the future, the household was more likely to have insurance. If a household had dependents, the household was more likely to have insurance. As income or monthly expenditure increased, the probability of haying insurance and the amount of the insurance increased However, savings or social insurance were positively related to the purchase of insurance.

• KEPCO Journal on Electric Power and Energy
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• v.8 no.2
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• pp.79-86
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• 2022

Recently, the amount of maintenance is increasing due to the aging of power facilities, but the budget is constrained. Therefore, the importance of asset management that selects replacement priorities based on the failure probability and enhances investment effects is increasing. Because the number of distribution transformers is very large, the proportion of investment cost is very high. Therefore, it is important to select the investment priority by evaluating the reliable remaining life based on the failure probability. This paper evaluates the statistical expected life using the failure data of distribution transformers for the last 11 years and the current operation data. The hazard rate of distribution transformer and MV cable was compared with each other and the adequacy of early failure removal was reviewed and the statistical expected life corresponding to the cumulative failure probability B3% was calculated.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2000.10a
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• pp.109-114
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• 2000

In this paper, an optimum design model for minimizing the life-cycle cost (LCC) of high-speed railway steel bridges is proposed The point is that it takes into account service life process as a whole, and thus the life-cycle costs include initial (design, testing, and construction) costs, maintenance costs, expected strength failure costs and expected serviceability failure costs. The problem is formulated as that of minimization of expected total life-cycle cost with respect to the design variables. By processing the optimum LCC design the effective and rational basis is proposed for calculating the total LCC and the sensitivity analysis of LCC is peformed. Based on a numerical example, it may be positively stated that the optimum LCC design of high-speed railway steel bridges proposed in this study provides a lot more rational and economical design, and thus the proposed approach will expedite the development of new concepts and design methodologies that may have important implications in the next generation performance-based design codes and standards.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.4
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• pp.102-110
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• 2010

The reliability evaluation may be a efficient method for estimating of the quantitative structural safety considering the effect of uncertainties included in high-speed railway bridges. The expected life-cycle cost(LCC) based upon the reliability evaluation will reasonably offer the safety level and design criteria of high-speed railway bridges. Therefore, this study determined the expected life-cycle cost and optimal design method of high-speed railway bridges on the basis of the result of the numerical analysis and reliability evaluation. For this, after creating various design method based upon the standard design of high-speed railway bridges, the numerical analysis is conducted on each of the alternative design methods. The reliability evaluation by the design strength limit state function is conducted considering the effect of external uncertainties on the basis of the numerical analysis result. The expected life-cycle cost of high-speed railway bridges is calculated on the basis of the reliability evaluation result by each of the alternative design methods. Also, the optimal design method is determined using the calculated expected life-cycle cost. In addition, The result of reliability evaluation and expected life-cycle cost of optimal design method are examined considering the effect of internal uncertainties. It is expected that the result of this study can be used as a basic information for the systematic safety evaluation and optimal structure design of high-speed railway bridges.

• Journal of Applied Reliability
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• v.16 no.4
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• pp.280-286
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• 2016

Purpose: Recently, Jiang defines the tradeoff B life to minimize a sum of life lost by preventive maintenance (PM) and corrective maintenance (CM) contribution parts and sets up an optimal replacement age of age replacement policy as this tradeoff life. In this paper, Jiang's model only considering the known lifetime distribution is extended by assigning different weights to two parts of PM and CM in order to reflect the practical maintenance situations in application. Methods: The new age replacement model is formulated and the meaning of a weight factor is expressed with the implied cost of failure under asymptotic expected cost model and also discussed with one-cycle expected cost criterion. Results: The proposed model is applied to Weibull and lognormal lifetime distributions and optimum PM replacement ages are derived with corresponding implied cost of failure. Conclusion: The new age replacement policy to escape the estimation of cost of failure in classical asymptotic expected cost criterion based on the renewal process is provided.

• Journal of the Korean Data and Information Science Society
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• v.21 no.1
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• pp.71-86
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• 2010

In life insurance, the net premium is derived based on the expected life time distribution and expected interest rate. The losses or risks of the insurer are significantly affected by the obtained net premium. Thus, in life insurance, these two factors, the life time distribution and expected interest rate, are considered as important influential factors. In this paper, we investigate the effect of these influential factors on the net premiums, management risks, and the probability of losses. Furthermore, relative influence of these factors is also studied.

• Journal of Families and Better Life
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• v.30 no.4
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• pp.25-35
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• 2012

The purpose of this study is to find out influence the difference between expected marital life and actual martial life and communication between husband and wife have on their quality of life among couples who have less than 5 years of their married life. 276 questionnaires were used for 138 couples who have less than 5 years of marital life living in D city. Technical statistic analysis, t-test, correlation analysis, and regression analysis were conducted to analyze the data using SPSS WIN 18.0. The research results are as the followings. Verbal communication showed to have influence on husband's quality of life whereas difference between expected marital life and actual martial life as well as verbal communication have influence on wife's quality of life. Therefore, it is recommended that a program needs to be developed to promote efficient communication between husband and wife raising their quality of life and they should not expect unrealistic marital life and think about the meaning of marriage deeply before getting married.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1158-1164
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• 2007

Recently, the demand on the practical application of life-cycle cost effectiveness for design and rehabilitation of civil infrastructure is rapidly growing unprecedentedly in civil engineering practice. Accordingly, it is expected that the life-cycle cost in the 21st century will become a new paradigm for all engineering decision problems in practice. However, in spite of impressive progress in the researches on the LCC, so far, most researches in Koreahave only focused on roadway bridges, which are not applicable to railway bridges. Thus, this paper presents the formulation models and methods for uncertainty-based LCCA for railroad bridges consideringboth objective statistical data available in the agency database of railroad bridges management and subjective data obtained form interviews with experts of the railway agency, which are used to anew uncertainty-based expected maintenance/repair costs including lifetime indirect costs. For reliable assessment of the life-cycle maintenance/repair costs, statistical analysis considering maintenance history data and survey data including the subjective judgments of railway experts on maintenance/management of railroad bridges, are performed to categorize critical maintenance items and associated expected costs and uncertainty-based deterioration models are developed. Finally, the formulation for simulation-based LCC analysis of railway bridges with uncertainty-based deterioration models are applied to the design-decision problem, which is to select an optimal bridge type having minimum Life-Cycle cost among various railway bridges types such as steel plate girder bridge, and prestressed concrete girder bridge in the basic design phase.

• Fashion & Textile Research Journal
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• v.26 no.1
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• pp.15-24
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• 2024

At a time when the direction of the middle and high school curriculum is being discussed in line with the change in the future education paradigm to the 4th industrial revolution and the post-COVID-19 era, this study attempted to establish the identity of middle and high school clothing life education by exploring the clothing life contents with content analysis method and analyzing the 'clothing life industry' related educational content of the curriculum revision period. Following the revision of the curriculum, the contents related to the middle and high school 'clothing life industry' were not systematic. In the 2022 revised curriculum, the 'clothing life industry' and the digital fashion industry are presented as content related to the 'clothing life industry', so it is expected that the textbooks implemented in the educational field in the future will mention specific content about this. In addition, research on the direction of sustainable clothing life is also needed because the 'clothing life industry' can be an important cause of environmental pollution from production to consumption. Above all, it is expected that follow-up studies will be conducted to enhance the value of clothing life education in the future in the reality that the awareness of middle and high school clothing life education is low.