• Molecules and Cells
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• v.38 no.8
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• pp.729-733
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• 2015

C. elegans has two functional peroxidasins (PXN), PXN-1 and PXN-2. PXN-2 is essential to consolidate the extracellular matrix during development and is suggested to interact with PXN-1 antagonistically. pxn-1 is involved in neuronal development and possibly maintenance; therefore, we investigated the relationship between pxn-1 and pxn-2 in neuronal development and in aging. During neuronal development, defects caused by pxn-1 overexpression were suppressed by overexpression of both pxn-1 and pxn-2. In neuronal aging process, pxn-1 mutants showed less age-related neuronal defects, such as neuronal outgrowth, neuronal wavy processes, and enhanced short-term memory performance. In addition, pxn-2 overexpressing animals retained an intact neuronal morphology when compared with age-matched controls. Consistent with these results, overexpression of both pxn-1 and pxn-2 restored the severe neuronal defects present with pxn-1 overexpression. These results implied that there is a negative relationship between pxn-1 and pxn-2 via pxn-1 regulating pxn-2. Therefore, pxn-1 may function in neuronal development and age-related neuronal maintenance through pxn-2.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.6
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• pp.191-197
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• 2006

This study is to establish a standardization of injection system by inorganic material for crack repair of tunnel concrete structures. For this various surveys and experiments were carried out as followed. The first we surveyed capability of injection and crack pattern of concrete structures in site. and second we analyzed the relationship between crack width and volume of injection, and decided pressure and volume of injection. Finally we evaluated the relationship between crack width and volume of injection with kind of concrete structures, and between required time for injection and crack width with thickness of structure. From these surveys and experiments, we cleared the relationship between crack patterns and injection technologies such as volume, pressure of injection and required time for injection with kind of structure.

• Journal of the Ergonomics Society of Korea
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• v.36 no.5
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• pp.559-568
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• 2017

Objective: The aim of this study is to investigate the effective managerial factors influencing dose reduction of the nozzle dam installation and removal tasks ranking within top 3 in viewpoint of average collective dose of nuclear power plant maintenance job. Background: International Commission on Radiation Protection (ICRP) recommended to reduce unnecessary dose and to minimize the necessary dose on the participants of maintenance job in radiation fields. Method: Seven sessions of nozzle dam installation and removal task logs yielded a multiple regression model with collective dose as a dependent variable and work time, number of participants, space doses before and after shield as independent variables. From the sessions in which a significant reduction in collective dose occurred, the effective managerial factors were elicited. Results: Work time was the most important factor contributing to collective dose reduction of nozzle dam installation and removal task. Introduction of new technology in nozzle dam design or maintenance job is the most important factor for work time reduction. Conclusion: With extended task logs and big data processing technique, the more accurate prediction model illustrating the relationship between collective dose reduction and effective managerial factors would be developed. Application: The effective managerial factors will be useful to reduce collective dose of decommissioning tasks as well as regular preventive maintenance tasks for a nuclear power plant.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.8
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• pp.1-7
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• 2010

The reliability of a power system has close relationship with the maintenance of the distribution systems. This paper presents the method of the maintenance planning of the distribution systems by minimizing the interruption cost. The interruption cost for the equipment failures is formulated using time varying failure rate and minimized by optimization of the object function. The proposed method provides the priority list for the investment of the maintenance subject to the limited investment budget by the economic analysis. In order to test the proposed method, the modified distribution system of a rural area is introduced for the testing system. Test results show that the proposed method is good enough by evaluating the improvement of the reliability of the power system.

• Journal of Korean Society of Transportation
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• v.21 no.3
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• pp.23-35
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• 2003

This paper investigates the effectiveness of flight operation between airplane maintenance engineers and pilots who work together. The developed model is to identify the relationship between the attitudes of airplane maintenance engineers and pilots and the effectiveness of flight operation. The results indicate that the shared values and balanced power between airplane maintenance engineers and pilots are positively related with trust and job satisfaction, but conflict is negatively related. Further, trust and job satisfaction positively affect the effectiveness of flight operation. These findings suggest that the improvements of the relationships between airplane maintenance engineers and pilots need more efforts to ensure the aviation safety and efficient flights.

• International conference on construction engineering and project management
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• 2007.03a
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• pp.186-195
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• 2007

Key Performance Indicators (KPIs) are the criteria of measuring project performance in order to attain construction excellence. Previous researchers have examined the abstract concept of success for general new construction and identified its relationship with the factors of success. In fact, most buildings exist to satisfy the needs of people. With the passing of time and change in technology, buildings have to be maintained and renovated in order to continue functioning properly for the benefits of users. Therefore, criteria and factors of success have increasingly attracted the attention of both researchers and practitioners, especially in cities where buildings become ageing. However, the topic of project success for maintenance projects is less discussed in previous research, and project participants, including maintenance surveyors should be able to identify the success measurement and its associated factors for performance improvement. This study fills the research gap by investigating the criteria and factors of success for maintenance projects. It first provides a summary of the literature review on the criteria and factors of success for construction projects. An empirical study has also been carried out with ten practitioners in Hong Kong to further identify the criteria and factors critical for the success of maintenance projects in practice. While most criteria and factors of success for new construction projects are also applicable to maintenance projects, participants in maintenance projects believe that effective communication is in particular important to provide quality service to the end-users.

• Management & Information Systems Review
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• v.30 no.4
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• pp.415-440
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• 2011

Purposes of this paper are to find out the implementation strategy of TPM activities for SMEs through the analysis which examine the relationship between key activity factors and business performance. TPM activity has been playing a important role to strengthen the competitive power of the enterprises through the optimization of equipment management and maintenance. This study has been conducted using the data collected from 124 SMEs propelling TPM activity. By analyses of the questionnaires, empirical results shows that TPM activities has positive effect on business performance. The contribution of this study is that it provides a conceptual framework and empirical evidence of the causal relationship between key activity factors and business performance. The result of this study can be used for selection of the performance measurement indicators for target achievement in TPM activity. And it will contribute for objectivity of activity performance in case of displaying measurement indicator showing the performance of TPM activity.

• Journal of Fashion Business
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• v.11 no.2
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• pp.1-13
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• 2007

The purpose of this study is to confirm Customer Voluntary Performance as a new strategy that contributes to Service Quality and maintains customer Relationship, and to understand how Service Quality and Relationship Benefits on Customer Voluntary Performance. To pursue the above purposes, the experimental model showing the working process was designed like this: Service quality - Relationship Benefits - Customer Satisfaction - Relationship Quality - Customer Voluntary Performance. To accomplish the experimental study, questionnaire method was chosen and targeted women living seoul. 721 questionnaires were used in last analysis. SPSS 8.0 was used in analysis of data. The results show that (1)Customer satisfaction was affected by Service Quality and Relationship Benefits affirmatively; (2)Relationship Quality was affected by Customer Satisfaction, Service Quality, Relationship Benefit; (3)Customer Voluntary Performance was affected by Relationship Quality and Customer Satisfaction; (4)Service Quality and Relationship Benefits influenced on Customer Voluntary Performance. This study has a important meaning that it provides marketing strategy on satisfied relationship maintenance and customer satisfaction creation.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.177-183
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• 2009

This paper deals with the topical problems of the Life Cycle Costs in connection with the rolling stocks. the LCC philosophy has already entered the third decade. this philosophy contributed towards the new relationship's comprehension between railway vehicle producers' and railway vehicle users' sphere. this leads together to the technical-economical solution convenient for the both sides. In the point of manufacturer, It is said that low operational costs could be reached using a well-designed and structured maintenance program. this is due to the proper technical analysis of critical components that leads to low costs of maintenance and a superior reliability without increasing the capital investment. but, This paper presents both topical experiences with the LCC models for the railways vehicles and also procedures during Life Cycle Costs calculations. In conclusion I want to introduce how to calculate LCC & what kinds of softwares are used based on VVVF EMU vehicle

• Journal of the Korean housing association
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• v.14 no.4
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• pp.11-19
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• 2003

This study intends to predict prospective defects and establish the plan of Preventive Maintenance through research and analysis of defect occurrences and their repair costs in the public equipment of ‘H’ apartment house from 1998 to 2001. According to results of the analysis, more than 90% of defects and their repair costs for 4 years of the building have occurred in heating, hot water and water supply equipments. In case of specific classification in each equipment, more than 60% of defects were found at hot water pipes and heating pipes, and their repair costs covered more than 60% of the total defect costs. After two repairs by ‘Preventive Maintenance’ had been performed in the year 1998, total defects and defects of each equipment each yew have increased in number from 1999 to 2001. But total repair costs and repair costs of each equipment have not increased as time has gone by, because repair costs have relationship with the price of materials and labor, the part of defect and the scale of repair.