• Journal of the Korean Society for Aviation and Aeronautics
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• v.24 no.4
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• pp.1-5
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• 2016

As a dependency on Global Navigation Satellite System (GNSS) becomes increase in various applications, its reliability has been very important. However, in South Korea, Global Positioning System (GPS) jamming incident happened four times since 2010. GNSS signal is so weak that it is highly susceptible to all types of the jamming. GNSS jamming can cause serious damage in the safety-critical applications based on the GNSS. In this paper, we present the GNSS jamming signal propagation prediction simulator based on ITU-R P.1546 model. This simulator is developed for preventing or reducing the damage from the GNSS jamming attack by predicting the jamming propagation strength based on the geographical information in Korean peninsula.

• Proceedings of the KIEE Conference
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• 2008.04b
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• pp.96-99
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• 2008

On-line condition monitoring is a useful tool for maintaining and extending the longevity of power transformers. An intelligent diagnostic system is desirable for operational safety and reliability. Bringing these concepts together results in a powerful support tool for engineers, reducing the volume of data to deal with, and making the data more meaningful. This paper describes how a multi-agent system for diagnosing the cause of transformer partial discharge activity was coupled with a method of UHF partial discharge monitoring, creating an on-line condition monitoring system. The challenges presented by the on-site environment are discussed, along with the implications for the complete system.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.23 no.1
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• pp.120-125
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• 2015

Passengers and Airlines wish neither delay nor cancellation due to aircraft defects. However, about 1 delay or cancellation case occurs out of 100 departures worldwide whereas 1 quarter case does in Korean domestic industry. Independent LCC carriers in Korea have almost double case. Most cases are recovered by replacing aircraft components. Airlines have prepared the spare components based on the reliability data by manufacturers to rectify defects or perform preventive maintenances. The total value for initial spares including engine is 40% of the aircraft price when they operate less than 5 aircraft. The more airlines operate the aircraft, the less the ratio of the investment for spares reflecting the economy of scale. This study intends to suggest how to improve the efficiencies as well as the safety of LCC throughout parts pooling including engines.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.1260-1262
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• 2001

The rubber type AGT system is operated by driverless that signaling is CBTC type. The system function is acomplished exactly to obtain the safety and reliability of system and the system is designed to minimize risk. In order to design the system, the functional analysis is performed. Recently functional analysis is performed by RDD-100 which is used and verified by aerospace, military, etc. Therefore The design tool RDD-100 is used to perform functional analysis in AGT system development project.

• Proceedings of the KIEE Conference
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• 2005.11b
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• pp.35-38
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• 2005

This paper suggests the method that forecast Dynamic Line Rating (DLR). Thermal Overload Risk (TOR) of next time is forecasted based on current weather condition and DLR value by Monte Carlo Simulation (MCS). To model weather element of transmission line for MCS, we will propose the use of weather forecast system and statistical models that time series law is applied. Also, through case study, forecasted TOR probability confirmed can utilize by standard that decide DLR of next time. In short, proposed method may be used usefully to keep safety of transmission line and reliability of supply of electric Power by forecasting transmission capacity of next time.

• Nuclear Engineering and Technology
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• v.19 no.4
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• pp.266-278
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• 1987

This paper addresses the issues in setting performance criteria for safety regulation of nuclear power plants. Since setting criteria at the low level is a much more difficult task than it is at the top level, the low-level performance criteria should be derived consistently from the more easily determinable top-level performance criteria. The paper also proposes several approaches to characterizing uncertainties in performance criteria, by extending the reliability allocation methodology that is based on the mean-to-mean mapping to a stochastic multi-objective optimization problem where the state variables are uncertain.

• Proceedings of the Korean Society for Quality Management Conference
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• 2010.04a
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• pp.254-261
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• 2010

The increase in hazard level is attributed to the industrial hazard environment; complete national environmental hazards to human health include climate change. The damage level in Korea from 1993 to 2009 has exceeded the Increase In adverse environmental conditions. Priority areas of concern will include those risks that are most likely to occur and are expensive when they do take place such as accident or injury at a community pool. Therefore, in this paper, we suggest the System Engineering method for application to the railway RAMS. Recently, the requirement of high-integrity level of infrastructure has been deemed important. The systems level approach is defined through the assessment of the RAMS interactions between elements of complex system applications.

• 한국태양에너지학회:학술대회논문집
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• 2012.03a
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• pp.433-438
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• 2012

LED is expected as an environmentally friendly next generation light source with its good reliability and long lifetime. In this paper, we propose the PV-Battery Driven LED Security Lighting using the LabVIEW program. The remote monitoring is a program for monitoring the voltage and current that made from PV-Battery Driven LED security lighting in remote area. The main subject of this paper is about making the more useful monitoring program to get and save the data from LED Security Lighting. We develop a prototype of the proposed system.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.14-19
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• 2005

An accelerated life test (ALT) is used to estimate the reliability of machinery parts and system with a design specification as soon as possible. However, accelerated life test results with simple and severe conditions are inconsistent with physical phenomena in real service condition. Therefore, to assure the safety of the machinery system, it is necessary to establish the appropriate test condition of the ALT of machinery element. In this study, fatigue analysis of the spur gear as a part of the gear box system in the rolling stock was performed. Moreover, based on the results, appropriate test condition of the ALT is developed using both the probabilistic model of the linear damage rule and accelerated durability analysis simulation.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.266-271
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• 2007

In these days, private investment for railway business has been expended and the importance of asset management arose. Especially new concept and effective management for the maintenance of railway have been developed. RCM(Reliability Centered Maintenance) is suggested to optimize the maintenance task and the proper maintenance decision logic for each system has been needed. But there are a lot of difficulties to apply the maintenance decision logic which has been developed in Aviation fields to railway. In this paper, the study on the development of the maintenance decision logic will be introduced through the risk analysis which has been applied to analyze the safety of railway.