• Advances in concrete construction
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• v.8 no.1
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• pp.55-64
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• 2019

Chloride corrosion has become the main factor of reducing the service life of reinforced concrete structures. The object of this paper is to propose a theoretical model that predicts the service life of chloride-corrosive concrete under fatigue load. In the process of modeling, the concrete is divided into two parts, microcrack and matrix. Taking the variation of mcirocrack area caused by fatigue load into account, an equation of chloride diffusion coefficient under fatigue load is established, and then the predictive model is developed based on Fick's second law. This model has an analytic solution and is reasonable in comparison to previous studies. Finally, some factors (chloride diffusion coefficient, surface chloride concentration and fatigue parameter) are analyzed to further investigate this model. The results indicate: the time to pit-to-crack transition and time to crack growth should not be neglected when predicting service life of concrete in strong corrosive condition; the type of fatigue loads also has a great impact on lifetime of concrete. In generally, this model is convenient to predict service life of chloride-corrosive concrete with different water to cement ratio, under different corrosive condition and under different types of fatigue load.

• International Journal of Advanced Culture Technology
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• v.9 no.4
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• pp.18-28
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• 2021

This study surveyed how retirees' evaluation of starting food service business affects the effectiveness their new business and quality of life, based on personal factors such as entrepreneurship and business-starting capability and environmental factors by using questionnaires. Bootstrapping was carried out in order to find out factors affecting rapidly changing new business environments and retirees' initial intent to start a business so as to verify basic hypothesis about relation between retirees' evaluation of starting food service business (social, economic, and psychological effects) and the effectiveness of their new business and quality of life and confirm whether the effectiveness of the new business acts as a medium between the evaluation of starting food service business and quality of life. In addition, PLS-MGA was performed in order to verify whether the correlations among test factors can be varied according to the kind of job the target retirees had. Having examined the basic thesis, it was found that social and economic factors had significant positive effect on the effectiveness of the new business, and social and psychological factors had significant positive effect on the quality of life. Having analyzed whether the effectiveness of new business acted as a media between evaluation of starting food service business and quality of life, there was no significant effect as a medium. Having studied whether the kind of job of the retirees controlled or affected the relations among evaluation of starting food service business, effectiveness of new business and quality of life, the results were as follows: in the office job retiree group, the greater economic factor led to increase of effectiveness of new business, while social and psychological factors influenced the quality of life; In the physical labor group, the higher social factor resulted in higher effectiveness of new business, which showed significant positive effect on the quality of life. Having researched about which element is considered to be most important in starting food service business, the most important element was found to be dish/menu, followed by staff management, accounting management, business management, and service education. Having analyzed relation between accomplishment and important consideration for starting food service business, "managers with entrepreneurship," "appropriate distribution of time to prepare for starting business," and "operation of practical field education programs" showed higher importance compared to the degree of satisfaction, so it is needed to more concentrate on the above matters. This study intends to raise retirees' awareness of starting business and help them live better life based on the analysis results, and further suggest detailed mechanism and specific operations of factors affecting retirees' decision making on starting business, such that they can use the information as basic materials to make better choices that can lead to successful business.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.163-167
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• 2017

The service life extension of the missile can reduce the replacement cost of the missile, maintain the combat power, and consist of the lifetime assessment of the shelf-life(energetic) items, the maintenance of the missile and upgrade of the related components. This technology should be developed together with the missile system and advanced sustainedly. It is a converging technology that combines various fields of expertise and long-term experiences and databases.

• Journal of Korea Water Resources Association
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• v.50 no.10
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• pp.673-679
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• 2017

In this paper a method for estimating the 'service life' and 'residual life' of a water pipe based on the Water Pipe Network Performance Evaluation(WPNPE) results of Water Supply Technical Diagnosis was developed for efficient maintenance of water pipes. The residual life of a pipe was defined as the difference between the service life and elapsed time since installation. The service life was defined as the time when a pipe reaches the reference score for determining deteriorated pipes that was used in the WPNPE. The pipe evaluation criteria and deterioration scores used in the WPNPE for the case study area were considered as independent variables in the multiple regression model for estimating the service life and residual life of the pipes in the area. To estimate the service life for the pipes the reference scores for determining deteriorated pipes were used as the values of the variables that represent the deterioration scores in the constructed regression models. Subsequently, the statistics of the service life and residual life of the pipes in the case study area were presented and analyzed in comparison with the service life defined by the Local Public Enterprizes Act.

• Journal of the Korean Wood Science and Technology
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• v.43 no.5
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• pp.641-651
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• 2015

The aim of this study was to estimate the service life of alkaline copper quaternary (ACQ)-treated wood. The service life of preservative-treated wood was estimated by comparing a residual quantity of ACQ in wood with toxic threshold to fungi. Indoor and outdoor leaching tests were carried out in order to predict residual ACQ quantity within wood. As a result, the leaching ratio of ACQ from treated wood above ground via precipitation was 18.1% for 50 years. When the H4 treated wood, which is traditionally used in contact with the ground and fresh water, is used above-ground, the leaching ratio of ACQ for 50 years is 18.1% and the residual quantity of ACQ is $4.2kg/m^3$, which is higher than the toxic threshold of ACQ. Thus, the H4 treated wood used above-ground will be resistant to biodeterioration for at least 50 years.

• Journal of Distribution Science
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• v.16 no.6
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• pp.85-96
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• 2018

Purpose - There are many antecedences and consequences of the positive emotions of customers. The purpose of this research is to examine how Chinese service companies improve not only the positive emotions of customers but also the quality of life through effective verbal and nonverbal communication. Furthermore, we tried to analyze the moderating role of negative expectancy disconfirmation perceived by customers in those causal relationships among the variables. Research design, data, and methodology - The eight hypotheses were proposed and we tested them empirically in this research. Four hypotheses were about the relationship among communication, positive emotion, trust and quality of life. The other four hypotheses were about the moderating effect of negative expectancy disconfirmation in the causal relationships among four variables such as communication, positive emotion, trust and quality of life. A total of 356 samples who had visited the service companies in China were surveyed and 8 hypotheses were tested by empirical analysis using SPSS and AMOS. Results - The results of this research are as follows. First, positive verbal communication and nonverbal communication of employees in the service company have a positive effects on the positive emotions of customers. Second, positive emotion has a positive effect on the overall quality of life on the customer side as well as the trust on the corporate side. Third, negative expectancy disconfirmation perceived by customers has negative moderating effect in the causal relationship between employees' positive verbal communication and customers' positive emotion, and it also has a negative moderating role in the causal relationship between customers' positive emotion and overall quality of life. Conclusions - Based on these results, there can be such implications as follows. First, managers and employees of service companies can induce positive emotion of customers through effective communication. Second, service companies should try to improve not only the corporate-side performance like trust but also the customer-side performance like quality of life. Third, it will be significant for them to lower the level of negative expectancy disconfirmation for the purpose of improving not only the positive emotions of customers but also the quality of customers' life.

• Journal of Families and Better Life
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• v.23 no.4 s.76
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• pp.1-15
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• 2005

Korean society is experiencing rapid changes which are certain to shape the lives of the older people and their families. So, the purpose of this study was to improve the quality of the elderly welfare service in Korea. Even though the interest about the elderly welfare in Korea is rapidly on the increase, the reality of Korean Society still leaves much to be desired, quantitatively as well as qualitatively. Pay attent to this point, now going to grasp the situation of not the handicapped elder people but the general elder people actual life condition and demand for welfare. So this study focused on the demand of not out-of home service but in-home care service. It was based on the data from by Korea National Statistical Office, having observed 6,139 elderly people. The results were as follows. They hope to get the elderly welfare services about health examination service, nursing survice, supporting service for household. That was, the most of them wanted in-home care service than out-of home care service. To ensure effective care to the elderly, it needed development and settlement of welfare service in face of their daily living. And, even though they recognized that they should cover the elderly life expenses themselves, the rate was hit that indicated their adult children as a parents supporter. This means that we should consider not only to the elder people but also to the family which contained the old people as the elderly welfare service. As a remedy, we can find the cooperation between elder welfare service at the social welfare organization and counsel, education at the family strengthen center. To improve the quality of the elderly welfare service in Korea, the elderly welfare service should focus not only on the physical and spiritual health maintenance but also active understanding living environment and growing ability to arbitrate between individual and living.

• Journal of Families and Better Life
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• v.24 no.6 s.84
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• pp.47-60
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• 2006

The purpose of this study was to find out which factors can affect customer satisfaction in the life insurance industry. Specifically, it was designed to investigate whether there were significant differences in the perceived service quality according to demographic characteristics to investigate whether there was a significant relationship between each service quality type and consumer satisfaction and to investigate whether the location in demographic characteristics serves to moderate the links between the perceived service quality and customer satisfaction. Data were collected from insurance subscribers living in Seoul and the Gyeonggi-do area and 364 questionnaires were taken into account in the analysis. Major findings of this study were as follows: First, there were significant differences in the perceived service quality according to demographic characteristics. Second, there were significant differences in customer satisfaction according toeach service quality type. Finally, the location in demographic characteristics did serve to moderate the links between the perception of service quality and customer satisfaction.

• Journal of Fisheries and Marine Sciences Education
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• v.29 no.3
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• pp.719-731
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• 2017

The aim of this study was to analyze a group of pre-service elementary teachers experience on the cognitive terms of biology inquiry subjects, and experience on living materials related with the domain of life in the Korea elementary school science textbook. Firstly, elementary school pre-service teachers had the confidence of inquiry subjects related with the domain of life such as 'when we take breath what will happen in human body?' and 'Can we make the model of human body?' But they did have the most diffidence of 'The search for pieris rapae, a cabbage butterfly's life', 'Can we grow the little creature?' The reason why pre-service elementary teachers had diffidence of comprehending experiment procedure and planning ability was that 'they focused on understanding the scientific concepts instead of planning experiments by themselves', and 'they carried out the least amount of experiments' Secondly, elementary school pre-service teachers had never experienced biology materials related with the domain of life in the Korea elementary school biology science textbook such as 'tradescantia reflexa', 'Caddis larva', 'hydrilla verticillata', and 'Plantain lily.' According to the findings obtained from the study, the reason why they had never seen the biology materials was that they had the least opportunity of immediately observing life creatures due to memorization-intensive classes.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10b
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• pp.1255-1260
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• 2000

The service life is defined as the period of the period of time, until repair becomes necessary to maintain the serviceability of structures. It is getting more common to specify the service life of a structure, particularly structures exposed to de-icing salt water. To accomplish this study, pier in the harbor was chosen as a experimental area. The service life of decks in marine environment was calculated as sum of three period ; initiation period, propagation period and cracking period. The object of this study is to indicate where and how measures can be adopted for checking relevant service lifes.