• Korean Journal of Digital Imaging in Medicine
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• v.16 no.1
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• pp.61-67
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• 2014

The demand of cyclotron for PET (positron emission tomography) has rapidly grown as the more use of PET or PET-CT equipment requires the increased amount of radioactive isotopes for clinical positron emission. While research on failure statistics of medical equipment used in medical centers has continued to be done, the analysis and study on failure statistics of cyclotron have rarely been conducted. However, the growing demand shows the urgency of systematical management guideline and countermeasures for device failure to minimize any supply delay of radiopharmaceuticals occurred by such failure and complains from waiting patients for PET-CT diagnosis. Therefore, this study aims to analyze the failure report from Minitrace equipped in cyclotron which is owned by the department of nuclear medicine at Yeungnam University Medical Center and draws on the data to build effective management system for cyclotron.

• Proceedings of the KIEE Conference
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• 2003.11a
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• pp.272-274
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• 2003

Distribution system reliability evaluation estimates by approach methods such as Makove modelling or Monte Carlo simulation, equation of state and failure rate that is on one basic data used to these assessment technique is described as probability of average value. because average failure rate equipment device is aged as time goes by but there is shortcoming that such used failure rate does not evaluate thing which is correct in reliability change hereafter. In this paper, failure rate displayed that apply aging to basis equipment device by passing time using Weibull distribution one of life evaluation method and for express aging of component from utility's failure database.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.717-723
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• 2011

When the Balise(the device to transmit information between the on-board equipment and the wayside equipment) failure occurs, it may not be able to transmit data(Telegram) required for the train running. And in some cases, it may be able to cause an accident. Therefore, both the Balise failure affecting train safety running and the hazard in accordance with Balise failure require some activities to establish them. General failure mode & hazard analysis associated with the Balise are described in UNISIG SUBSET-036 spec & UNISIG SUBSET-088 spec. And, with reference to these specifications, safety activities are being performed. In recent domestic railway, the train control system applying ETCS(European Train Control System) Level 1, 2 is being serviced and is being planned, and as part of this system, the Balise is being applied. The design-method of the Balise device for each manufacturer are different, therefore the Balise failure mode & failure rate are different, either. But the functionalities & transmission-data format(Telegram) of the Balise in ETCS Level 1, 2 application for each manufacturer are identical. Accordingly, the hazard caused by function-fail can be identical, either. In order to establish these hazard, in this paper, we analyzed the detailed functions of the Balise. And we analyzed the Balise failure types & failure effects in accordance with the detailed functions.

• Journal of Electrical Engineering and Technology
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• v.4 no.1
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• pp.43-48
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• 2009

The purpose of the this paper is to make decision of the maintenance priority of power distribution system using Time-Varying Failure Rate(TVFR) with interruption cost. This paper emphasizes the practical use of the reliability indices and interruption cost. To make a decision of maintenance priority on power distribution system equipment, the quantification of the reliability level should be represented as a cost. In this paper, the TVFR of power distribution system equipment applied in this paper utilizes analytic method to use the historical data of KEPCO. From this result, the sensitivity analysis on TVFR of equipment was done for the priority, which represents that high priority of the equipment has more effect on system reliability, such as SAIDI or SAIFI, than other equipment. By this priority, the investment plan is established. In this result, customer interruption cost(CIC) could be extracted, and CIC is used as weighting factor to consider a importance of customer. After that, the result calculated the proposal method in this paper is compared with other priority method, such as lifetime, failure rate or only sensitivity.

• Journal of the Korean Institute of Gas
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• v.26 no.4
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• pp.18-26
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• 2022

The Korean government is conducting heat-using equipment(industrial boiler) inspection in accordance with the Energy Use Rationalization Act because of the heat-using equipment(industrial boiler)'s risks such as explosion and fire, and safe use and management. This paper aimed to setup the safe and performance vulnerabilities from database based on the inspection results for heat-using equipment(industrial boiler). This study surveyed the inspection results of 1,249 heat-using equipment(industrial boiler) which were failed inspection of heat-using equipment(industrial boiler) from january 2016 to december 2020. And the analysis method is to inform safety and performance vulnerability categories of heat-using equipment(industrial boiler) by statistically analyzing the failure reasons of boiler type and inspection type which are high variance in failure rate. The safety and performance vulnerability categories was abbreviated into 18 cases. And each catagory's main reason for failure was suggested by additional analyzing the opinions of inspectors. This paper would be the basic source and the comprehensive information dealing with the safety and performance vulnerability of heat-using equipment(industrial boiler).

• Journal of the Korean Institute of Gas
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• v.21 no.4
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• pp.16-20
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• 2017

Current maintenance system are unable to suggest solid basis of maintenance for roating and static equipment. When a filure occurs, replacement or repair without proper process of failure cause analysis would often result in even greater risk. Therefore in this study, a procedure of Reliability Centred Maintenance is develped in order to perform maintenance in preventive mainer (PM), and to effectively manage risk of any equipment based on failure types and respective rates of failure. Ultimately an equipment with higher risk will be monitored which will lead to effectively prevent and manage any major accident.

• Journal of the Earthquake Engineering Society of Korea
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• v.24 no.3
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• pp.141-148
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• 2020

For the important safety system, two or more units of identical equipment or redundant components with similar function were installed to prevent abnormal failure. If the failure probability of such equipment is independent, this redundancy could increase the system safety remarkably. However, if the failure of each component is highly correlated by installing in a structure or experiencing an earthquake event, the expected redundancy effect will decrease. Therefore, the seismic correlation of the equipment should be evaluated quantitatively for the seismic probabilistic safety assessment. The correlation effect can be explained in the procedure of constructing fragility curves. In this study, several methodologies to quantify the seismic correlation in the failure probability calculation for multiple components were reviewed and two possible ways considering the realistic situation were selected. Simple examples were tested to check the applicability of these methods. The conversion method between these two methods was suggested to render the evaluation using the advantages of each method possible.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.4
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• pp.358-363
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• 2012

The simulation investigation on the availability of LNG plant with scenario of failure events and failure rate has been carried out. This study focuses on the availability, productivity, criticality induced by failure rate of major equipment. The methodologies for simulation such as the equipment classification of LNG plant and failure type and event schematic are established. The availability and mean time to repair have second order function profile in the all cases except general equipment, but these profiles have different inclination. The production and criticality of the specified LNG plant, simulated by Monte-Carlo algorithm, is located in the range of P = 86~92% and PL = 6~13%.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.9
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• pp.1325-1330
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• 2010

The breakdown of any critical component of a turbine results in the outage of power plants. Unexpected failure decreases equipment utilization and causes enormous economic losses. Currently, we conduct conservative preventive maintenance for a maintenance period that is proposed by a vendor. In the rapidly changing business environment, reliability-based maintenance is required in order to remain competitive and reduce maintenance costs while maintaining the reliability of equipment. In order to determine an appropriate maintenance period for guaranteeing reliability, we must determine the failure probability by carefully analyzing the failure history of the equipment. In this study, we created a database of failure history for power-plant turbines, predicted the best repair time using the Weibull function, and investigated how the appropriate maintenance cycle can be determined.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2006.06b
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• pp.363-366
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• 2006

In the port, Yard Crane is very important. If container crane or transfer crane broke down, it costs much money for delaying of work during the period of repair or reorder. But, we can not have enough spare parts for its high cost. It is necessary for having the reliability of crane through the effective preventive maintenance and failure analysis. In this paper, we analysed the system's function and failure mechanism of transfer crane which is main equipment in the yard. Also, we standardized the failure and maintenance work using the historical data of failure and maintenance. This study which is the basic work for IT of equipment operation and maintenance is going to be new attempt for optimal design of next generation equipment and operation policy of equipment.