• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.1
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• pp.226-234
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• 2011

The service life of concrete structures exposed to a marine environment can be extended by controlling the amount of chloride in cover concrete. Patching is one of the appropriate maintenance techniques for chloride contamination. Chloride-contaminated cover concrete is removed and replaced with sound one. It can provide less risk of corrosion of steel, so that the structure can be maintained for required service life. In this study, a quantitative assessment of the service life subjected to the chloride attack is proposed to determine the effective repair options such as repair depth, repair material and timing of repair. The Crank-Nicolson based finite difference formulation from Fick's second law is proposed to predict the profiles of chloride ion in a repaired concrete structure, considering ingress of chloride from outer and redistribution of residual chloride from the substrate concrete. Therefore, the repair application times and maintenance cost for the target service life can be estimated. Finally, the numerical examples are presented to ensure its applicability.

• Journal of the Korean Home Economics Association
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• v.49 no.7
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• pp.1-11
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• 2011

This study identified the use types of a home help service and the level of service quality and reviewed the extent of their effects on consumer satisfaction. As a result of measuring the service quality in terms of support, assurance, reliability, empathy and responsiveness, a high overall reliability was demonstrated in the service. The consumer satisfaction with the home help service was discovered as being high, in general. Meanwhile, with the female research participants, the lower the service fee was perceived to be, the higher the consumer satisfaction. The quality assessment items concerning support and reliability were found to be important variables which were influential on consumer satisfaction. Therefore, it has been shown to be imperative to prepare political alternatives regarding the development of the service standard in order to protect user's rights, offer relevant information, and ensure reliability in the home help service.

• Membrane and Water Treatment
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• v.11 no.3
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• pp.173-177
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• 2020

Wastewater treatment plants (WWTPs) have been recognized as one of the significant greenhouse gas (GHG) generators, due to the complex biochemical reaction and huge consumption of energy and materials. Recently, WWTPs have been built underground and they will be confronted with the challenges of mitigating GHG emissions and improving the quality of treated wastewater. Here, we focus on estimating GHG emissions to set up effective management plans for a WWTP built underground. First, we apply the process-based life cycle assessment (LCA) with an inventory database of the underground WWTP for a case study. Then, we identify significant factors affecting GHG emissions during service life using sensitivity analysis and suggest the proper tactics that could properly reduce GHG emissions from the WWTP.

• Journal of Drive and Control
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• v.15 no.4
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• pp.48-54
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• 2018

The hydraulic servo actuator has always operated very precisely with high frequency and small displacement, and is used continuously for a long time. The hydraulic servo actuator of the test equipment used in the accelerated life test in order to guarantee the service life of the automotive parts failed earlier than the products before finishing the test. This study performed an analysis on the cause of the failure of the hydraulic servo actuator used in the test equipment, changed the design of the actuator to solve the root cause of the main failure mode, and developed the improved servo actuator. Based on above process, this study established a better performances and longer lifetime of the servo actuator after testing.

• Korean Journal of Community Nutrition
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• v.18 no.2
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• pp.142-153
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• 2013

The purpose of the study was to examine nutritional management and nutritional care demands of home-visit care service and the nutritional status of serviced elderly. The survey was carried out from $5^{th}$ to $21^{st}$ of January, 2011 among 37 In-Home Service institutions. The number of elderly surveyed by 143 care helpers was 281. Analysis was performed for 203 subjects (male: 44, female: 159). The age distribution was from 50 to 99 years. The grading by long-term care insuranceshowed 18,2% on level 1 and 2, and 81.8% on level 3. For the disease treatment, the proportion of implementing diet treatment turned out to be very low. The proportion of subjects living with their children was 45.3%, and living alone was 29.1%. The proportion of home-visit care among types of In-Home Service was 70%. Subjects who needed additional necessary diet management service turned out to be 40.9%. Diet management was the most necessary services from all levels. MNA (specifiy MNA) scores were significantly (p < 0.001) associated with BMI, mid-arm circumference (MAC), calf circumference (CC), intake problems, and weight loss during the last 3 months. For studied elderly, 45.3% were malnourished, and 46.8% were at the risk of malnutrition by MNA score. Based on the result of this survey, the nutritional care was not systematic on the In-Home Service. Prevention and management of the disease was much better than the treatment to improve the quality of life. We conclude that nutrition management is necessary for the elderly. To improve nutritional status of elderly in home care services, systematic nutrition management should be implemented.

• Journal of Environmental Impact Assessment
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• v.4 no.2
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• pp.123-130
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• 1995

The equipment composed of many complicated electronic stuffs undergoes diverse stresses caused by mechanical vibrations during its service. Thus, to ensure its proper operation in the field a simulated vibration test has to be carried out in the laboratory with the Vibration Qualification Level, the test specification, which can include the real environment. In this paper we intent to deal with method and procedure for determining the Vibration Qualification Level so as to estimate the vibration-endurance for the equipment precisely.

• Journal of the Korean Institute of Gas
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• v.25 no.5
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• pp.30-36
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• 2021

Residual life assessment of reformer tubes of mod HP steel used in the refinery and petrochemical industry were investigated by quantitative metallographic evaluation method. Area fractions of precipitated carbides were measured by using surface replication and its relationship with the remaining life of the tube was investigated. The microstructures of the virgin and other tubes were examined using optical microscopy (OM) for service periods of 1.8, 6.0, 7.2, 8.5, 9.7, and 16.2 years at 950 ℃ and the area fractions of the precipitates were measured by image analysis using ImageJ software. As the area fraction of the precipitates increased, the residual life was decreased accordingly. The results showed that the LMP was the highest in the virgin and the LMP decreased as the service time increased and the residual life decreased. A regressional equation showing the relation between the area fraction of carbides and LMP was experimentally derived. The obtained relationship can be used with the surface replication method for on-site residual life assessment.

• Journal of Construction Engineering and Project Management
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• v.4 no.3
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• pp.47-52
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• 2014

In the last decades, Facility Management (FM) has established itself as a key building service factor.FM includes supporting services and organizing functions essential for maintaining, operating and managing physical component and material. The purpose of the paper is to develop an economical analysis for building facilities management during its service life based on limited cost. This method helps to facilities managers and engineers to make better decisions for reducing of facilities assessment costs and increasing the facilities' service life. This paper presents the preliminary development of a model involves three stages process namely data collection, economic computation and economic process optimization. This process was tested for fiberglass doors example in a building interior and exterior system. If executives can manage essential points effectively and make decisions according to a key performance index, cost can be optimized and safety can be enhanced for installation building.

• Journal of Korean Academic Society of Home Health Care Nursing
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• v.12 no.1
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• pp.136-154
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• 2005

Purpose : This study purposed to conduct a comprehensive survey of home care nursing clients' quality of life based on the PRECEDE model. Method : This study selected 74 home care nursing clients registered at a university hospital in Incheon and performed face-to-face interviews by structured questionnaire. The research period was two months from the $2^{nd}$ of February to the $30^{th}$ of March in 2004. Result : According to the result of assessment at each stage of the PRECEDE model, home care nursing clients' quality of life was 13.88 out of 25 points, health level 15.22 out of 21, abilities to perform activities of daily living 29.26 out of 100, cognitive abilities 16.00 out of 30, social support 13.68 out of 20, and satisfaction with home care nursing service 33.26 out of 40. According to the result of stepwise regression in order to identify factors influencing home care nursing clients' quality of life, social support and abilities of daily living were found to be significant variables among the characteristics of each assessment stage. Conclusion : It is necessary to develop nursing intervention strategies for strengthening social support and enhancing abilities to perform activities of daily living in order to improve home nursing clients' quality of life.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2007.04a
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• pp.3-17
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• 2007

This paper provides an introduction to life-span simulation and numerical approach to support the performance design processes of reinforced concrete structures. An integrated computational system is proposed for life-span simulation of reinforced concrete. Conservation of moisture, carbon dioxide, oxygen, chloride, calcium and momentum is solved with hydration, carbonation, corrosion, ion dissolution. damage evolution and their thermodynamic/mechanical equilibrium. Coupled analysis of mass transport and damage mechanics associated with steel corrosion is presented for structural performance assessment of reinforced concrete. Multi-scale modeling of micro-pore formation and transport phenomena of moisture and ions are mutually linked for predicting the corrosion of reinforcement and volumetric changes. The interaction of crack propagation with corroded gel migration can also be simulated. Two finite element codes. multi-chemo physical simulation code (DuCOM) and nonlinear dynamic code of structural reinforced concrete (COM3) were combined together to form the integrated simulation system. This computational system was verified by the laboratory scale and large scale experiments of damaged reinforced concrete members under static loads, and has been applied to safety and serviceability assessment of existing structures. Based on the damage details predicted by the nonlinear finite element analytical system, the life-span-cost of RC structures including the original construction costs and the repairing costs for possible damage during the service life can be evaluated for design purpose.