• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2009년도 제33회 추계학술대회논문집
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• pp.15-18
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• 2009

우주발사체 개발을 위한 75톤급 액체로켓엔진 개발에 앞서 선행개발을 통해 습득한 30톤급 액체로켓 엔진 기술을 토대로 75톤급 액체로켓엔진 연소기 기술 검증에 착수하였다. 이를 위하여 국내 연소시험 설비 여건을 고려한 기술검증 계획을 수립하고 기술검증시제를 제작하여 제한된 조건에서 성능평가시험을 수행하였다. 본 논문은 75톤급 액체로켓 연소기 기술검증을 위한 계획과 현황에 대하여 소개한다.

• 신재생에너지
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• 제10권3호
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• pp.22-30
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• 2014

The isolated self-generating electricity with diesel engine generator has been used in islands far away from main land. It costs high because of increasing oil price, and unsafe to have supplying oil and its related components by ship due to unexpectable marine conditions. Therefore there is the need for the hybrid system of renewable energy like wind or solar energy systems with oil engine generator, which can reduce oil use and extend oil supplying period. In this study, the feasibility of such hybrid system with smart micro grid on the eight islands of Jeon-nam province is surveyed to find good place for the demonstration test of the hybrid system. In each island, 3 wind turbine systems of 10 kW and photovoltaic of 20 kW are tested with already installed diesel engine. The performance and costs of the hybrid system in each island are compared in the given conditions of solar and wind energy potential. As a result of the study, Jung-ma island is recommended for the optimum place to make real field demonstration test of isolated hybrid generating and smart grid systems.

• 한국신뢰성학회지:신뢰성응용연구
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• 제15권3호
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• pp.170-175
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• 2015

Reliability demonstration tests (RDT's) are widely employed in design verification and process validation stages of industry. New mixed attribute-variable RDT plans that compromise demerits of the corresponding zero and zero or one failure plans which are common in practice are developed for the exponential distribution. The proposed mixed plans are compared with the typical RDT plans in terms of probability of acceptance and expected test termination time. A numerical example is provided to illustrate the mixed plans and a procedure to extend these plans to the Weibull distribution with known shape parameter is also presented.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2022년도 춘계학술대회
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• pp.218-219
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• 2022

한국산업기술진흥원과 울산정보산업진흥원은 첨단 기술이 집약된 ICT융합 전기 추진 스마트 선박을 건조중이며 2022년 실증을 앞두고 있다. 선내 장비 실증을 위해 실증대상장비를 도출하였으며 실증시험 절차서 개발을 위해 우선적으로 선정된 대상장비는 전자해도표시시스템, 선박용 레이더 시스템, 항해기록장치, 선박에너지효율모니터링시스템이다. 본 논문에서는 우선 선정된 실증대상장비 4종에 대해 장비 표준에 기반한 실증절차와 실증시험 체크리스트 및 템플릿에 대해 소개한다.

• 한국IT서비스학회지
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• 제7권2호
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• pp.113-125
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• 2008

To test if the developed ubiquitous health care devices working well and vital information could be collected and monitored systematically through internet and to test if the devices and services could be used further. Kyungwon University, KT Co., Gil Medical Center, LIG Nex1 Co., and Sujeong Health Center conducted an ubiquitous health care demonstration project in Sujeong-Gu, Sungnam, Korea from Mar. 5 to May 16. We developed and applied several medical devices to monitor health of the elderly in their houses through internet. The devices were sphygmomanometer, glucometer, body fat scale, Health Pad, and activity sensor. We distributed the devices to 20 recipients of home care and 7 diabetes patients. After received the devices and were explained how to use them, they used the devices in their houses. The vital signs of the residents were monitored through internet. A nurse monitored and consulted their vital signs in the monitoring center in Kyungwon University during the demonstration period. The consultant called them and consulted on their blood pressure, blood sugar level, and body fat after a few seconds they used the devices as well as provision of recommended contents such as diets and activities through Health Pad. To investigate cognition and satisfaction of the participants for the devices, we surveyed the participants at the end of the demonstration period. For the change in blood pressure, blood sugar level, and activities, we conducted statistical test. After the demonstration period. cognition and satisfaction for the devices and change in blood pressure, blood sugar level, and activities were evaluated. Most of the participants were acknowledged how to use the device and satisfied with the use of the devices. The internet monitoring and services are considered to be promising because most of the participants were satisfied especially because somebody was monitoring their health status. However some weaknesses such as short battery life of the activity sensor, lack of connection of consultations with hospitals, and low understanding on usage of some of the devices need to be complemented.

• Journal of the Korean Data and Information Science Society
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• 제27권4호
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• pp.1067-1074
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• 2016

A start-up demonstration test is a mechanism that is usually used to determine the reliability of equipment, for example water pumps, car batteries and power generators. The simplest and oldest start-up demonstration tests are called CS (consecutive successes) which have been studied by Hahn and Gage (1983), Viveros and Balakrishnan (1993).At first Hahn and Gage (1983) discussed the start-up demonstration test. I was based on i.i.d (independently and identically distributed) binary outcomes with the specified number of consecutive successful start-ups. Oh (2016) studied CSNCF (consecutive successful, but not consecutive failures). In this paper, we investigated the CS and CSNCF models, also their applications to start-up demonstration tests. The numerical results showed that the expectations and variances of the total number of attempted start-ups until the acceptance of the unit are gradually increasing in all of the specified number of successes as the p (probability of a successful start-up in an single trial) decreases from 0.99 to 0.90. The difference between means of the CS mode and CSNCF model is small, but variances of the CS and CSNCF are big.

• 한국신뢰성학회지:신뢰성응용연구
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• 제14권1호
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• pp.1-9
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• 2014

One important measure of performance for a repairable system is steady-state availability. In this paper, a method to estimate and establish confidence interval for the steady-state availability under Weibull lifetime and lognormal repair time distributions is proposed. Also, bias and mean squared error of a point estimator for an availability are investigated. In addition, a procedure to derive the sample size and critical value for availability demonstration test is presented and illustrated with a numerical example.

• 산업경영시스템학회지
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• 제35권2호
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• pp.98-105
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• 2012

This paper describes the Bayesian approach for reliability demonstration test based on the samples from a finite population. The Bayesian approach involves the technical method about how to combine the prior distribution and the likelihood function to produce the posterior distribution. In this paper, the hypergeometric distribution is adopted as a likelihood function for a finite population. The conjugacy of the beta-binomial distribution and the hypergeometric distribution is shown and is used to make a decision about whether to accept or reject the finite population judging from a viewpoint of faulty goods. A numerical example is also given.

• 비파괴검사학회지
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• 제24권4호
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• pp.378-383
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• 2004

국내 원자력발전소의 Class1과 Class2 배관검사에 적용할 수 있는 초음파탐상 검사자, 장비 그리고 절차서에 대한 한국형 기량검증(KPD) 시스템을 구축하였다. PD 방법을 적용한 검사결과와 전통적인 dB-drop 방법을 이용한 검사결과를 상호 비교하기 위하여 Round Robin Test(RRT)를 수행하였다. RRT 결과는 PD 방법의 신뢰성이 dB Drop 방법보다 우수한 것으로 나타났다. 이러한 결과로부터 원자력발전소 가동중검사에 PD 방법을 적용함으로써 초음파탐상검사 결과의 신뢰성이 더욱 향상될 것으로 기대된다.

• 품질경영학회지
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• 제34권1호
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• pp.20-26
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• 2006

In the fields of mechanical reliability application, "zero" or "zero or one" failure tests are most commonly used for demonstrating reliability of a product since they reduce test duration and/or sample size compared to other test methods that guarantees the same reliability of a product with a given confidence level or consumer's risk. The test duration of the "zero or one" failure test is longer than that of "zero" failure test but it has advantage of smaller producer's risk. In this paper a two-stage test is developed that compromises the "zero" and "zero or one" failure tests. The properties of the proposed two-stage test are investigated and the three test methods are compared using a numerical example.