• Plant Journal
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• v.12 no.2
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• pp.31-35
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• 2016

A method of failure data management for Reliability-Centered Maintenance was shown for a boiler feedwater pump of a power plant. The major part of it is an analysis of failure mode, failure cause, and failure effects, which is the main component of a failure data base like OREDA(Offshore Reliability Data). Case study shows main element of the preventive maintenance planning such as the maintenance period can be statistically determined from the failure data.

• Journal of Korean Clinical Nursing Research
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• v.27 no.1
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• pp.85-97
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• 2021

Purpose: The purpose of this study was to develop a video education program (VEP) for the caregivers and to verify its effectiveness on the maintenance of a peripheral intravenous catheter (PIVC) among hospitalized children. Methods: The VEP was developed through a literature review, educational need assessment of caregivers, and interviews with pediatric nurses, and validation of an expert group. The effectiveness of the VEP was tested on 102 caregivers and their children in a children's hospital at D city. A nonequivalent control group pretest-posttest design was used in which different types of intervention were given to caregivers in intervention group (n=51) and control group (n=51). All caregivers received brief verbal information about the PIVC maintenance. The intervention group was additionally provided with VEP using a smartphone. Data were analyzed using SPSS/Win 21.0 program. Results: The caregivers' knowledge score on PIVC maintenance in the intervention group was significantly higher than that of the control group. The numbers of flushing in case of blockage of PIVC and gauze dressing change of the intervention group was significantly lower than those of the control group. Conclusion: These results suggest that the VEP developed in this study can be useful for the maintenance of PIVC among hospitalized children.

• International Journal of Railway
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• v.2 no.2
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• pp.60-69
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• 2009

In recent years, technology developments in different countries, especially in newly industrialized countries, are extremely indebted to appropriate technology transfer by these countries. Nevertheless the technology transfer process in the present situation is complex, and its success is related to the coordination rate with the political, economic, social, and environmental objectives of countries. Today debates related to the transfer of the technical know how accompanied by equipment hardware has found remarkable importance such that countries seek increasing comprehensive capabilities in the field of transferred technology for which Preventive Maintenance (PM) is one of the aspects. This research with the purpose to determine the technological capability level and to study the role of PM in the effective & appropriate technology transfer in subway industry is carried out for presenting a suitable model for the technology transfer in this industry with an attitude towards the effects of principal PM factors. For this purpose, after the study of different and relevant models existing in the field of suitable methods for technology transfer, some equipment PM theories and models were selected as the base for the compilation of the questionnaire. With the help of questionnaire, main PM factors that are effective in the field of technology transfer were extracted, and finally, their effects on technology transfer were analyzed, identified and a comprehensive model suggested in this connection.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.1
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• pp.70-76
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• 2012

The purpose of this study is to analyze of the operating characteristics of the Gas engine driven Heat Pump(GHP) and to reduce maintenance costs through the most Economical plan. As the zoning modifications that have economic effects were confirmed. Applications should be made with a similar purpose of the space. The combination of a modified space has led to reduced operating hours of the outdoor unit. The reduction of the outdoor unit operating hours, reducing maintenance costs accordingly. When analyzed at six years have elapsed, the amount of savings through zoning modifications is more than an additional construction cost. During the design phase, cost-effective operation of the GHP is required for the proper zoning plan.

• Geomechanics and Engineering
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• v.14 no.6
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• pp.563-570
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• 2018

Ballast layer has an important role in vertical stiffness and stability of railway track. In most of the Middle East countries and some of the Asian ones, significant parts of railway lines pass through desert areas where the track (particularly ballast layer) is contaminated with sands. Despite considerable number of derailments reported in the sand contaminated tracks, there is a lack of sufficient studies on the influences of sand contamination on the ballast vertical stiffness as the main indicator of track stability. Addressing this limitation, the effects of sand contamination on the mechanical behavior of ballast were experimentally investigated. For this purpose, laboratory tests (plate load test) on ballast samples with different levels of sand contamination were carried out. The results obtained were analyzed leading to derive mathematical expressions for the strain modulus ($E_V$) as a function of the ballast level of contamination. The $E_V$ was used as an index for evaluation of the load-deformation characteristics and bearing capacity of track substructure. The critical limit of sand contamination, after which the $E_V$ of the ballast reduces drastically, was obtained. It was shown that the obtained research results improve the current track maintenance approach by providing key guides for the optimization of ballast maintenance planning (the timing of ballast cleaning or renewal).

• Journal of Korean Critical Care Nursing
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• v.11 no.1
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• pp.79-88
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• 2018

Purpose : This study was performed to evaluate the effects of a prolonged a $30^{\circ}$ side-lying position on comfort and skin condition by applying the trunk maintenance repositioning method, which can keep the $30^{\circ}$ side-lying position effective for preventing pressure ulcers. Method : Fifty-four healthy nurses working at a general hospital in Seoul were randomly assigned to an experimental group (n=27) or a control group (n=27) and assumed a position of lying on their right or left side for two hours. The trunk maintenance repositioning method was applied to the experimental group using the pillow made by the researcher, while the original repositioning method was applied to the control group using the regular pillow from the subject hospital. Participants' posture angles, comfort, and skin condition were measured at the time of the intervention, as well as at one and two hours after the intervention. Results : There was no statistically significant difference in position angle, comfort, skin condition change, or sacrum and greater trochanter pressure change between the two groups over time. Conclusion : It is necessary to review the method and frequency of change of position in each hospital. In addition, a proper position changing pillow should be developed in consideration of patients' various body shapes.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.11
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• pp.591-598
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• 2009

The service quality with the various building equipments tends to depend on the individual superintendent's capability and efforts generally and this often lead to poor maintenances and managements of them. N-BMS(Networked Building Management System), proposed in this study, is a new type of building management method, which links principal equipments within many buildings into a communication network and carries out several significant missions such as fault detection, deterioration diagnosis and control the equipments and so on, as well as monitoring which is the main and unique purpose of the conventional BMS. How to construct the N-BMS was considered to keep performance of equipments high and thus to save energy and resource. LCC(Life Cycle Cost) based analysis was also performed in order to verify the effects of some maintenance and management works for the building HVAC systems.

• Structural Monitoring and Maintenance
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• v.6 no.2
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• pp.85-101
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• 2019

The effects of foundation scour depth and riverbed condition on the natural frequencies of a typical cross-river integral abutment bridge have been studied. The conventional operational modal analysis technique has been employed in order to extract the modal properties of the bridge and the results have been used in the Finite Element (FE) model updating procedure. Two tests have been carried out in two different levels of water and wet condition of the riverbed. In the first test, the riverbed was in dry condition for two subsequent years and the level of water was 10 meter lower than the natural riverbed. In the second test, the river was opened to water flow from the upstream dam and the level of water was 2 meter higher than the natural riverbed. The results of these two tests have also been used in order to find to what extend the presence of water flow in the river and saturation of the surrounding soil affect the bridge natural frequencies. Finally, the updated FE model of the bridge has been applied in a series of parametric analyses incorporating the effect of piles' relative scour depth on the bridge natural frequency of the first four vibration modes.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.5
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• pp.36-47
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• 2010

The Korean Railroad Research Institute (KRRI) has developed the rubber tired AGT system (Model: K-AGT) between 1999 and 2005. The K-AGT is a light rail transit system does not require a driver and generally operates on an elevated railroad for transporting passengers. Accidents caused by driverless vehicles can severely affect social confidence, safety and economy therefore, it is very important to minimize the occurrences of such faults, and to accurately perform detailed maintenance tasks and thoroughly investigate the cause of any repeated failures. This research develops the web-based Preventive Maintenance (PM) system for the KAGT train system. The framework of the PM system is based on performing a reliability analysis and a failure mode effects analyses (FMEA) procedure on all the sub-systems in the K-AGT system. Out of the devices that have a low reliability, the high failure ranked devices are included high in the list for performing the overall maintenance plans. Through registration of historical failure data, the reliability indexes can be updated. Such a process is repeated continuously and can achieve very accurate predictions for device operational life times and failure rates. Therefore, this research describes the development of the overall PM system consists of a reliability analysis module, a failure mode effect analysis module, and maintenance request module.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.1
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• pp.48-55
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• 2016

The assessment and prediction of service life of a structure are usually under uncertainty so that rational probabilistic concepts and methods have to be applied. Based on these rational assessment and prediction, optimum maintenance strategies to minimize the life-cycle cost and/or maximize the structural safety can be established. The service life assessment and prediction considering maintenance actions generally includes effects of maintenance types and times of the structural components on the service life extensions of structural system. Existing researches on the service life management have revealed the appropriate system modeling considering the correlation among the components is required for system reliability analysis and probabilistic service life estimation. However, the study on correlation among the maintenance actions is still required. This paper deals with such a study for more effective and efficient service life management. In this paper, both the preventive and essential maintenances are considered for the extended service life estimation and management.