• Smart Structures and Systems
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• v.4 no.5
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• pp.641-653
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• 2008

This paper proposes a practical and realistic method to establish an optimal lifetime maintenance strategy for deteriorating bridges by considering the life-cycle performance as well as the life-cycle cost. The proposed method offers a set of optimal tradeoff maintenance scenarios among other conflicting objectives, such as minimizing cost and maximizing performance. A genetic algorithm is used to generate a set of maintenance scenarios that is a multi-objective combinatorial optimization problem related to the lifetime performance and the life-cycle cost as separate objective functions. A computer program, which generates optimal maintenance scenarios, was developed based on the proposed method using the life-cycle costs and the performance of bridges. The subordinate relation between bridge members has been considered to decide optimal maintenance sequence and a corresponding algorithm has been implemented into the program. The developed program has been used to present a procedure for finding an optimal maintenance scenario for steel-girder bridges on the Korean National Road. Through this bridge maintenance scenario analysis, it is expected that the developed method and program can be effectively used to allow bridge managers an optimal maintenance strategy satisfying various constraints and requirements.

• Women's Health Nursing
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• v.21 no.1
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• pp.43-54
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• 2015

Purpose: This study was conducted to identify the problem of bone health and potential influencing factors of bone mineral density (BMD) for women across the life cycle of menopause. Methods: Complex sampling design data analysis was performed on the fifth Korea National Health and Nutrition Examination Survey 2010 in order to identify the problems with bone health, BMD and its influencing factors in 3,499 women who answered the menopausal status. Women's life cycle was categorized by premenopausal, postmenopausal, and elderly. Results: 35.1% of premenopausal women, 73.3% of postmenopausal women, and 96.0% of elderly women had problems with bone health that were related to low BMD. Influencing factors of BMD were residential area, alcohol drinking, and body mass index (BMI) for premenopausal women; age, residential area, education, marital status, income, and BMI for postmenopausal women; and age, education, and BMI for elderly women. Conclusion: Problems with bone health required to be considered as a major health problem in all women regardless their life cycle. Interventions to maximize BMD need to be developed by considering its influencingfactors across the women's life cycle.

• 한국태양에너지학회:학술대회논문집
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• 2009.11a
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• pp.394-399
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• 2009

Since some decades ago, there has been a concern for resource depletion and environmental pollution associated with building properties. In addressing such impact of the built environment, there is a recognition of the existence of alternative building materials, fuels for energy supply as well as technologies for waste handling and disposal. Nevertheless, for long time, the choice between such alternatives was dictated by factors such as differences in prices and aesthetic values. A new important dimension in discriminating between different options is the environmental dimension. This aspect is important since buildings are one of the spatially big new additions to the natural environment that consume a lot of materials and energy during their long lifetime. Thus, with the environmental dimension kept in mind, a existing cost estimation needs to be changed. A new cost assessment method, Life Cycle Cost, should calculate overall costs with dimensional factors: investment and utility costs as well as maintenance costs over the lifetime of the building. Aiming to give an overview of the present status of Building Life Cycle Assessment(LCA) tools as a basis for further research and development including economic performance, this paper describes and compares 3 different tools for Life Cycle Assessment(LCA) and economic analysis of the green buildings. This paper compared these approaches based on various aspects. These include economic analysis method, evaluation duration, data of results(index). Use of the comparison analysis is to produce a better picture and indicate profits and shortcomings for the tools as a group; thus providing important direction improvement of LCA tool as well as further research and development of this group of tools.

• Journal of Korea Water Resources Association
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• v.36 no.5
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• pp.715-724
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• 2003

It is true that SOC facilities, such as dams, need long life cycles since more time has to be invested for the phases of planning, examination, feasibility study, design, contract, construction, and maintenance. This longer life cycle is easily exposed to the risk. And thus, brings additional cost by the delayed project, convenient loss according to the additional run of use, and benefit lose of not to using the facilities. So, the purpose of this study is to try to find a solution to reduce these time consuming problems which could diminish the whole national competition. Hence, this study is to show efficient, systematical project performance and network model by using reciprocal analyses between the construction period and cost based on economical analysis of each phase of life cycles. In addition, on the basis of these outputs, the Fast Track Method is suggested as an alternative solution as a new Approach in Life Cycle's Analysis.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.12
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• pp.1830-1835
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• 2017

8200 Series Electric Locomotives are mostly imported from overseas due to aging and uncertainty of source technology, and it's the maintenance cost is increasing. We are analyzed life cycle costs based on international standards such as IEC 60300-3-3 and IEC62278. The main conversion system of the 8200 series electric locomotive is closely related to vehicle operation and is one of the subsystems requiring frequent maintenance. In this paper, the life cycle cost of the main conversion unit in 8200 series electric locomotive is analyzed based on the maintenance manual. As a result of analysis, maintenance cost of GTO module and control device is relatively high, and it is confirmed that the cost increases according to the useful life.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1123-1128
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• 2011

Generally, there are many types of data, such as wear data or irregularity data, are detected for analyzing railway performance. The analysis of railroad wear or irregularity data is most effective method for the efficient railway maintenance. Especially, the track damaged directly by train, have as important position with the inspection data. This study suggest the Life-Cycle performance analysis method and process of railroad by analyzing two types of data, wear data and irregularity data. This analysis methods can be applied to suggest the Life-Cycle performance of railroad based on environmental factors or design factors, such as sleeper type, roadbed type, cant, the radius of curvature, speed, maintenance history and so on.

• Steel and Composite Structures
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• v.29 no.3
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• pp.287-299
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• 2018

The purpose of this study is to investigate the effectiveness of damped cable systems (DCS) to mitigate the earthquake-induced responses of a building frame structure. The seismic performance of the DCS is investigated using the fragility analysis and life cycle cost evaluation of an existing building retrofitted with the DCS, and the results are compared with the structure retrofitted with conventional fluid viscous dampers. The comparison of the analysis results reveals that, due to the self-centering capability of the DCS, residual displacement approximately reaches to zero for the structure retrofitted with the DCS. The fragility analysis shows that the structure retrofitted with the DCS has the least probability of reaching the specific limit states compared to the bare structure and the structure with the conventional fluid viscous damper (VD), especially under the severe ground motions. It is also observed that both the initial and the life cycle costs of the DCS seismic retrofitting technique is lesser compare to the structure retrofitted with the VD.

• Journal of the Korean Society of Clothing and Textiles
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• v.33 no.7
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• pp.1050-1060
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• 2009

This study develops a scale for consumer clothing satisfaction based on Lee et al. 's (2002) five stages of the consumer life cycle (acquisition, possession, consumption, maintenance, and disposal). Data were gathered by surveying college students using convenience sampling, and 419 questionnaires were used in the statistical analysis. In analyzing the data, an exploratory factor analysis and a confirmatory factor analysis using a structural equation modeling were conducted. The proposed scale, which identified various sources of satisfaction and dissatisfaction associated with the 5 consumption cycles of clothing, suggests some guidelines for marketers in enhancing consumer clothing satisfaction across consumption stages. The model test for the scale also identified that consumption satisfaction had the greatest effect on consumer clothing satisfaction showing the strongest loading and squared multiple correlation.

• Journal of Korean Society of Water and Wastewater
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• v.11 no.2
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• pp.50-64
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• 1997

Life cycle assessment (LCA) on total sewage sludge treatment system from thickening to incineration and melting was performed for estimating global environmental impact as $CO_2$. In general, the life cycles of actual treatment facilities consist of construction, operation and dismantlement. In this study, the amount of $CO_2$ produced from both whole and each life cycle step of currently used unit sludge treatment processes were calculated by inventory analysis. In addition, in the all processes investigated in this study, individual $CO_2$ production unit (CPU), i.e. total produced $CO_2$ by treating a unit weight of sludge was also calculated. By using the CPU matrix of the unit processes, it was possible to simulate the $CO_2$ production for any type of complex-system as well as to trace a dominant cause of $CO_2$ production in each process. Four selected alternatives examined here, each involve the same disposal way but differ substantially in the $CO_2$ exhaust.

• 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.