• Proceedings of the Computational Structural Engineering Institute Conference
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• 2003.10a
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• pp.103-114
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• 2003

This paper aims to propose a method that helps maintenance engineers to evaluate the damage states of bridge structure systems by using a Fuzzy Fault Tree Analysis. It may be stated that Fuzzy Fault Tree Analysis may be very useful for the systematic and rational fuzzy reliability assessment for real bridge structure systems problems because the approach is able to effectively deal with all the related bridge structural element damages in terms of the linguistic variables that incorporate systematically experts experiences and subjective judgement. This paper considers these uncertainties by providing a fuzzy reliability-based framework and shows that the identification of the optimum maintenance scenario is a straightforward process. This is achieved by using a computer program for LIFETIME. This program can consider the effects of various types of actions on the fuzzy reliability index profile of a deteriorating structures. Only the effect of maintenance interventions is considered in this study. However. any environmental or mechanical action affecting the fuzzy reliability index profile can be considered in LIFETIME. Numerical examples of deteriorating bridges are presented to illustrate the capability of the proposed approach. Further development and implementation of this approach are recommended for future research.

• Journal of Korean Library and Information Science Society
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• v.43 no.1
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• pp.261-285
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• 2012

The purpose of this study is to confirm that the user benefit criteria can be applied as the user benefit criteria of children's libraries by examining the theoretical validity of the user benefit criteria and furthermore, by clarifying and verifying the mutual relation between the user benefit criteria and the child development area. For such a purpose, this study collected data from 247 users of children's libraries in the country and collected data was analyzed using the structural equation modeling. The result of analysis is as follows. First, the relation between physical development and behavioral facilitation, emotional development and physiological maintenance, cognitive development and perceptual maintenance, and the development of social skills and social facilitation was appropriate. Second, usability, safety and diversity was valid as an index of behavioral facilitation, self-esteem, amenity and peacefulness was valid as an index of physiological maintenance, esthetic sense, dynamics and flexibility was valid as an index of perceptual maintenance, and leisure, communication and territoriality was valid as an index of social facilitation. Third, children who prefer physical development prefer the benefit of behavioral facilitation, children who prefer emotional development prefer the benefit of physiological maintenance, children who prefer cognitive development prefer the benefit of perceptual maintenance and children who prefer the development of social skills prefer the benefit of social facilitation.

• Korean Journal of Child Studies
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• v.31 no.1
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• pp.163-177
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• 2010

The purpose of this study was to examine the maintenance of an evaluation accreditation indicator according to child care center teachers' participation in decision making. The subjects of this study were 139 teachers from 12 accredited national, public, private, and corporate child care centers in Seoul and North Gyeongsang Province. The TIP-2 (Teacher Involvement and Participation Scale V.2) and Accreditation Indicator for Child Care Centers were used to measure teachers' participation in decision making and accreditation indicator maintenance. Frequency, mean, standard deviation, one-way ANOVA and scheffe test were used for data analyses. The results revealed that the teachers who rated middle and high level in terms of their participation in decision-making showed higher levels of maintenance of the evaluation accreditation indicator than those with low levels of participation. This finding suggests that teachers' participation in decision making is an important factor for maintaining the quality of child care centers.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.3
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• pp.1-11
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• 2023

After the collapse of the Seongsu Bridge in the 1990s in Korea, attention was focused on the maintenance of facilities. The government has established various policies since the enactment of the Act in 1995 until recently. In general, safety inspections are performed to evaluate the safety grade of facilities, and facilities are maintained and managed by performing repairs and reinforcements for defects. However, since the budget is limited, it is impossible to carry out repair and reinforcement projects for all defects. It is necessary to prioritize repair and reinforcement measures. Then, the priority index (PI) is presented considering the importance of members, the seriousness of defects, and economic feasibility. In this index, the degree of influence can be adjusted within the range of 50 to 100% according to the expert's subjective judgment, and the same weight is set for some specific members. Also, the effect through repair and reinforcement is not taken into account decisively, and most of them have a limit in which priority is determined by economic feasibility. Therefore, in this study, through several case studies, problems with the priority index were reviewed and an equation was presented to improve them.

• Korean Journal of Construction Engineering and Management
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• v.19 no.1
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• pp.32-42
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• 2018

The importance of facility maintenance management cannot be overemphasized in that not only the value but also the performance of the facility is determined by the level of maintenance. The maintenance cost of the facility ranges from 3 to 10 times the initial construction cost depending the type and use of the facility over the life span. This maintenance importance is increased for the group of facilities and even more critical when the facilities compete for the limited budget with the limited resources such as manpower and equipment. This study analyzed sixteen public facility management corporations primarily for three items: 1) facility management system, 2) long-term rehabilitation plan, 3) the rehabilitation selection system. This paper provides and recommends the key elements of the facility maintenance management system based on the analysis of the sixteen corporations.

• 한국태양에너지학회:학술대회논문집
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• 2008.11a
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• pp.112-119
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• 2008

In order to ensure building energy management at an appropriate level continuously, it is necessary to define clearly service work of energy management and to suggest evaluation index whether energy management in buildings is fit and improvement is needed or not. But, evaluation index of energy management level in buildings is not suggested yet in Korea. So, the purpose of this paper is to suggest evaluation index of energy management level in buildings, investigate the present state of Korean buildings and evaluate energy management levels. As a result of surveys of evaluation index of energy management, it is found that portion of level 1, which is the best level, is higher than any other level, level 2, level 3. And, throughout analysis, it is found that as total floor area is larger, evaluation index of energy management level is better, and, in order to increase energy management level, first of all, there is necessary for building's users to change understanding about energy saving and make a reform of national policy of energy management in buildings. Because there is rich relationship between items among evaluation index of this stuff and result value of evaluation index, evaluation index of energy management suggested in this study is available to evaluate energy management level in buildings.

• Journal of the Korea institute for structural maintenance and inspection
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• v.9 no.2
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• pp.121-128
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• 2005

This study focuses on evaluating the reliability index of a deck of RC slab having chloride contamination and studying the relation of grades of rebar corrosion and the reliability index of a bridge deck For this purpose, first, the failure probability related to flexural strength was calculated using a model for deterioration, which contains the application of deicing salts that usually causes significant long-term deterioration and reduction in the structural safety for strength of structure. And also, according to the depth of covering, the chloride contents depending on time due to depths of RC slab deck, the appearance time for initial corrosion of rebar and the occurrence time for split of covering were investigated using a MCS method.

• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.5
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• pp.179-189
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• 2008

The object of this study is to develope a program with proposed numerical techniques for an optimal seismic control of structures using active tendon systems. Ricatti closed-loop algorithm has been applied to control the active tendon systems with time-delay problem. The optimal control is formulated as an optimization problem which is finding optimal weighting matrices by minimizing the quadratic performance index by SUMT. In order to find the optimal location of active tendons in structures, controllability index has been introduced. From numerical examples, the current optimal control technique with optimal location of tendons was suitable to control the seismic response of structures.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.4
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• pp.23-30
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• 2013

Reliability Centered Maintenance(RCM) is one of most widely used methods in the modern power system to schedule a maintenance cycle and determine the priority of inspection. A precedence study for the new structure of rearranged system should be performed due to introduction of additional installation. This paper proposes a new method to evaluate the priority of maintenance and inspection of the power system facilities. In order to calculate that risk index, it is required that the reliability block diagram should be analyzed for the power system. Additionally, a fault cause analysis is also performed through the event-tree analysis.

• International Journal of Railway
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• v.7 no.1
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• pp.8-15
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• 2014

Recently, in the total railroad construction field, concrete slab tracks have been adapted in place of ballast tracks. Because ballast tracks need frequent maintenance and are difficult to handle due to increasing maintenance costs, eventually concrete slab tracks were selected as an alternative. However, owing to the hydration heat reactions and temperature-affected shrinkage of the concrete, a variety of studies to solve maintenance problems related to concrete slab tracks are underway. This study analyzed characteristics of TQI values evaluating track irregularity, investigated the relationship between crack progress and TQI, and then evaluated the correlation between the two values. Through our analysis, we found that there is a need to supplement the problems of the current method and develop a track evaluation index which takes cracking into account. We also concluded that TQI is the main decision-making tool in track maintenance.