• Journal of the Institute of Convergence Signal Processing
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• v.16 no.3
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• pp.115-121
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• 2015

A device which could cut off the consumption of standby power by electric or electronic devices at homes and offices while waiting for a command to carry out the main functions from the inside or the outside was developed at a low price. Efforts to save standby power have been made on a global scale as well as by advanced countries. The consumption of standby power in South Korea is also increasing gradually due to increasing trend in the number of electronic and electric devices per household, becoming a major factor for waste of electric energy. The previous standby power cutoff devices themselves have high electric energy consumption and complicated structures, making the purpose less meaningful. Therefore, a low-priced standby power cutoff device is suggested in this study, which compensates such problems and cuts off the consumption of standby power completely. The circuit of the suggested standby power cutoff device was designed and implemented by applying it to an earth leakage breaker and an (electrical) outlet. Experimental results show its superiority.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.39
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• pp.87-103
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• 2008

Two kinds of security devices such as independent guarantees and standby letters of credit have been widely used in the international transactions. These devices design to protect one of the parties from a breach by its counter-party. Main uses of these guarantees and standby letters of credit are as follows : bid guarantee, performance guarantee, advance payment guarantee, payment guarantee, retention guarantee, etc. The standby letters of credit were first invented in the U.S.A. and have been widely used in the international and domestic contracts in the U.S.A. But the practical use of these credits is very unsatisfactory in Korea. The purpose of this study is to serve the increase of practical use of the standby letters of credit in Korea through the comparison study on the practical use of the credits between Korea and the U.S.A. Both devices are very similar in function, but they are very different in forms. The one has the form of letter of credits but the other has the form of guarantee. The letter of credit has the stability of governing rule, the legal certainty, and the preference in the field of the trade community comparing to the guarantee. I recommend to use standby letter of credit instead of bank guarantee in international transactions because of the merits of the credit aforesaid.

• Journal of Applied Reliability
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• v.15 no.4
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• pp.233-240
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• 2015

We analyse reliability of multi-state UH-60 helicopter hydraulic pump system with a multi-functional standby component using Markov analysis method. The system consists of seven components: 2 main pumps, 1 standby pump, 2 primary servos, and 2 tail rotor servos. The standby pump can take over when one more than components fail. Therefore the standby pump is multi-functional standby component. The system has four states: good, deteriorated, dangerous, and failed. The components have 2 states: working and failed. We assume the system is unrepairable when the components fail. We estimate failure distributions and rates using collected failure time data in field. And we classify multi-state of the system according to emergency procedure of UH-60A student handout. We obtain the reliabilities of multi-state system using Visual Basic program because the differential equations is extremely complicated and tedious to solve.

• Journal of the Korea Safety Management & Science
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• v.15 no.1
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• pp.161-167
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• 2013

The purpose of this study was to assess power loss in the computer and office automation equipment and identified a way to save power consumptions through field measurement. In this study, the meaning of standby power was to consume power while waiting for the use of any electronic equipment. This standby consumption was about 11% of total power consumption even though we did not seriously realize it. Therefore, it was very important to measure accurate power consumption at the standby status of electronic equipment. In addition, it also helped to reduce potential risks of electricity associated disasters. This study proposed the way to reduce power losses through automatic turn off switches for power outlets and switches. Finally, this study can evaluate power consumption patterns that can reduce power consumptions and potential risks of power related disasters. This also can achieve the goals of sustainability that can reduce environmental impacts by lowering energy consumptions and greenhouse gas emissions.

• Communications for Statistical Applications and Methods
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• v.8 no.2
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• pp.435-442
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• 2001

Bayes estimators and generalized ML estimators for reliability of a k-unit hot standby system with the perfect switch based upon a complete sample of failure times observed from an exponential distribution using noninformative, generalized uniform, and gamma priors for the failure rate are proposed, and MSE's of proposed several estimators for the standby system reliability are compared numerically each other through the Monte Carlo simulation.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.13 no.22
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• pp.59-64
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• 1990

This paper is aimed to study the standby redundant system with the relay of parallel structure, by making use of the character of standby system, which reliability is higher than parallel system's if the relay has higher reliability than a certain level. By assigning the low-priced relay to the subsystem, this method increases the relay reliability, optimizes the standby redundant system reliability without violating the restrictions, and consequently reduces the cost.

• Proceedings of the KAIS Fall Conference
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• 2010.05a
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• pp.330-332
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• 2010

이동통신시스템에서 Warm standby sharing에 비하여 Hot standby sharing은 데이터 손실이 없고 오류 데이터가 확산되지 않는 등의 다수의 장점을 갖지만 동기화 문제로 인하여 이를 시스템에 실제로 구현하는 것은 어렵다. 따라서 본 연구에서는 Hot standby sharing에 비하여 기존의 Warm standby sharing이 갖는 동기화의 장점에 데이터 손실 및 거짓 데이터의 확산 문제를 개선할 수 있는 이중화 프로세서에 대한 마코프 모델을 설계하고자 한다.

• Journal of Korea Society of Industrial Information Systems
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• v.20 no.4
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• pp.75-87
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• 2015

A redundant structure typically consists of primary component and standby component taking over the function of the primary component when the primary component fails. In this research, we consider a redundant structure in which a standby component can take over the function of more than one primary component when primary components fail. And we assume that the system has multi-state according to the states of components while all components have two states. This system is called as the multi-state redundant system with a multi-functional standby component. This type of redundant structure is frequently adapted by the system such as an aircraft in which the weight is an important design factor. In this paper, we propose new reliability model for this multi-state redundant system with a multi-functional standby component in order for evaluating the reliability of the system. Under the assumption that all components have constant failure rate, we evaluate the reliability of the system by applying Markov analysis method. And we investigate the effect of the multi-functional standby component by comparing reliabilities of the parallel system with multi-functional standby component and a simple parallel system and a parallel system with redundant structure.

• Journal of Korean Institute of Industrial Engineers
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• v.39 no.2
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• pp.90-98
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• 2013

The k-out-of-n system with mixed redundancy is defined as k-out-of-n system which both includes warm-standby and cold-standby components. In case that operating components in the system fail and the system needs quick transition of standby components to operation state, the k-out-of-n system with mixed redundancy is useful for decreasing system failure rate and operational cost. Reliability-Redundancy Optimization Problem (RROP) involves selection of components with multiple choices and redundancy levels for maximizing system reliability with constraints such as cost, weight, etc. A solution methodology by using harmony search algorithm for RROP of the k-out-of-n system with mixed redundancy to maximize system reliability was suggested in this study.

• Journal of the Korean Society for Railway
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• v.9 no.6 s.37
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• pp.725-731
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• 2006

Hot Standby sparing system detecting faults by using software, and being tolerant any faults by using Hardware Redundancy is difficult to perform quantitative reliability prediction and to detect real time faults. Therefore, this paper designs Hot Standby sparing system using hardware basis self checking logic in order to overcome this problem. It also performs failure mode analysis of Hot Standby sparing system with designed self checking logic by using FMEA (Failure Mode Effect Analysis), and identifies reliability assessment of the controller designed by quantifying the numbers of failure development by using FTA (Fault Tree Analysis)