• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.15-18
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• 2009

Technology demonstration for the development of a 75-tonf liquid rocket engine(LRE) thrust chamber for a space launch vehicle has been started on the basis of the previously acquired 30-tonf LRE technologies. For this purpose, a technology demonstration plan was established upon considering the currently available firing test facility in Korea and performance evaluation firing tests were performed on technology demonstration model thrust chambers under a restricted test condition. This paper describes the plan and current status of technology demonstration for a 75-tonf LRE thrust chamber.

• New & Renewable Energy
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• v.10 no.3
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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.

• Journal of Applied Reliability
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• v.15 no.3
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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.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.06a
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• pp.218-219
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• 2022

The Korea Institute for Advancement of Technology and the Ulsan ICT Promotion Agency are building an electric smart ship using a full range of ICT with advanced technology, and are expected to demonstrate it in 2022. For the demonstration of onboard ship equipment, it needs to develop a demonstration procedure. There are 4 types of onboard equipment preferentially selected for the development of the demonstration test procedure which are an electronic chart display and information system, a ship RADAR system, a voyage data recorder, and a ship energy efficiency monitoring system. This paper describes the demonstration procedure based on the equipment standard for the electronic chart display and information system among 4 selected types of demonstration equipment, and also the verification test checklist and template is introduced.

• Journal of Information Technology Services
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• v.7 no.2
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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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• v.27 no.4
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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.

• Journal of Applied Reliability
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• v.14 no.1
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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.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.35 no.2
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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.

• Journal of the Korean Society for Nondestructive Testing
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• v.24 no.4
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• pp.378-383
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• 2004

The Korean Performance Demonstration(KPD) System for the ultrasonic testing personnel, equipments and procedures applicable to the Class 1 and 2 piping examination for nuclear power plant in Korea has been established. A round robin test was conducted in order to compare the examination results by the method of Performance Demonstration(PD) with the traditional dB-drop method. The round robin test shows that the reliability of the PD method is better than that of the dB-drop method. As a result, adoption of the PD method to the in-service inspection of the nuclear power plants will improve the reliability of the ultrasonic test results.

• Journal of Korean Society for Quality Management
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• v.34 no.1
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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.