• Journal of Aerospace System Engineering
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• v.10 no.1
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• pp.51-58
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• 2016

In this paper, we present some results on No-failure accelerated life test of aerial vehicle for reliability demonstration. The design of general accelerated life test consists of the three phases: 1) Estimating normal life test time of a single product from Weibull distribution model; 2) Determining the acceleration factor (AF) by utilizing the relation between the life of mechanical components and the applied torque; 3) Calculating the accelerated life test time, which comes from dividing the estimated normal life test time into AF. Then, we applied the calculated life test time to the real reliability test of the flap actuating system, while considering the requirement specification for mechanical components and operating environment of the actuation system. Real experimental processes and results are presented to validate the theory.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.78.1-78.1
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• 2010

Recently, as much supplied with new-renewable energy, as much invested in PV system. PV system consists of PV module, PCS and Monitering system, and also could be classified into the type and the capacity by installation method and cost etc. When various systems are installed in the field, it is needed to research for applying in the field and establish infrastructure in order to ensure stable efficiency and reliability. In this study, as the basic design of the demonstration test facility, it is designed the basic PV systems for each capacity to test each PCS. In addition, It is drew the climatic conditions such as insolation, temperature and the design parameters such as installation angle, shades for the local demonstration project and expected the generation of each PV system.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.71-74
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• 2010

Using the technology demonstration model of 75-tonf-class combustor which is expected to be used to the rocket engine of a korean space launch vehicle, 2 times of firing tests were carried out. Firing tests were done at 50% of the nominal flow rate because of incapability of the test facility and limit of the test bed strength. Through the low pressure firing tests of 75-tonf-class channel cooling thrust chamber, reliability and stability at the ignition and combustion phases were confirmed. Additionally it was foreseen that the 75-tonf-class thrust chamber would satisfy the performance requirements.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.597-601
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• 2006

The advantages of solar energy are that it is renewable, infinite supplied and environmentally safe energy source. However, solar energy related products have the problems such as the limitation for installation, problems in maintenance and insufficient reliability which have been the barrier to consumers to satisfy the purchase need for solar heat related products. In this regard, in order to support the solar energy related companies the necessity for various technical information required for the commercialization of new products such as various performance test necessary for the certification of solar energy system, standardization for facilities and products, performance evaluation method and the measurement of performance is suggested. The purpose of this paper is to design the monitoring system for positive tests of system linked household hot water system using solar heat out of various solar energy systems, to establish an analysis and monitoring system for performance maintenance and operation technique, and to configure the centralized detection network by utilizing remote monitoring system. This research also aims at conducting monitoring for operation and performance evaluation in relation to database establishment and analytical evaluation and at describing the method of enhancing the reliability of solar energy system through the development of performance evaluation program.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.4
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• pp.165-170
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• 2020

In the rapidly growing new and renewable ESS parts and materials market, there is a limit for domestic SMEs to cope with the rapidly changing global new and renewable ESS market. There is a growing need to build a new and renewable ESS convergence commercialization support center. Therefore, through the establishment of a new and renewable ESS convergence professional evaluation center base, performance evaluation and standardization of new and renewable ESS products enhance product reliability. And By securing the reliability of new and renewable ESS, it is possible to promote domestic supply business and export activation. In addition, by supporting domestic research institutes and manufacturers to enhance their development capabilities and strengthen their competitiveness, and shortening the test cost and testing period according to the total-test evaluation system, it is possible anti-spill effect can be expected. Therefore, in this paper, we intend to study the establishment of a test certification center beyond the level of developed countries that can establish standardization for performance evaluation and demonstration.

• Journal of Korean Elementary Science Education
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• v.18 no.2
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• pp.21-33
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• 1999

The purpose of this study was to develop an Instrument for the Measurement of Cognitive Conflict Levels of students who confronted with an anomalous situation in science teaming. Anomalous situation is generated when students' prediction is disconsistent with the observed fact. In this study, the researchers identified 4 components of cognitive conflict and developed three items for each component. The items were developed and revised by four pilot tests. In the first pilot test, 55 elementary school students participated in the test In the second pilot test, 88 students of the 5th and 6th grader participated in the test. The instrument of measuring cognitive conflict levels was given to the subjects right after demonstrating anomalous situation. For the demonstration, two different problem situations were developed: one was a pulley problem and the other was electric bulbs in parallel. Answered reasons for each items were analyzed to assess students' understanding on each items. In third pilot test, 125 elementary school students participated in the test. A factor analysis of the responses was carried out and reliability of the test was assessed by calculating internal consistency values. The items were finalized by three pilot tests. After 1 month after the third pilot test, researchers conducted the finalized test items to 323 students of the 5th and 6th grader. The final instrument showed moderate reliability (Cronbach-α 0.82∼0.87) and good content validity(0.93). A factor analysis of the response was carried out. 4 main factors completely coincided with 4 components that we supposed to be the conducts of cognitive conflict. The instrument can provide a means for both teachers and researchers to assess the cognitive conflict of a large number of students within a single class period. The results can be used by teachers to better understand the process of conceptual change of their students and to match instruction and materials accordingly.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.403-407
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• 2005

Objective of the research is to demonstrate solar thermal space and ground heating system which is integrated to a greenhouse culture facility for reducing heating cost, increasing the value of product by environment control, and developing advanced culture technology by deploying solar thermal system. Field test for the demonstration was carried out in horticulture complex in Jeju Island. Medium scale solar hot water system was installed in a ground heating culture facility. Reliability and economic aspect of the system which was operated complementary with thermal storage and solar hot water generation were analyzed by investigating collector efficiency, operation performance, and control features. Short term day test on element performance and Long term test of the whole system were carried out. Optimum operating condition and its characteristics were closely investigated by changing the control condition based on the temperature difference which is the most important operating parameter. For establishing more reliable and optimal design data regarding system scale and operation condition, continuous operation and monitoring on the system need to be further carried out. However, it is expected that, in high-insolation areas where large-scale ground storage is adaptable, solar system demonstrated in the research could be economically competitive and promisingly disseminate over various application areas.

• New & Renewable Energy
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• v.1 no.2 s.2
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• pp.53-59
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• 2005

Objective of the research is to demonstrate solar thermal space and ground heating system which is integrated to a green-house culture facility for reducing healing cost, Increasing the value of product by environment control, and developing advanced culture technology by deploying solar thermal system. Field test for the demonstration was carried out in horticulture complex In Jeju Island. Medium scale solar hot water system was installed in a ground heating culture facility. Reliability and economic aspect of the system which was operated complementary with thermal storage and solar hot water generation were analyzed by investigating collector efficiency, operation performance, and control features. Short term day test on element performance and Long term test of the whole system were carried out. Optimum operating condition and its characteristics were closely Investigated by changing the control condition based on the temperature difference which Is the most important operating parameter For establishing more reliable and optimal design data regarding system scale and operation condition, continuous operation and monitoring on the system need to be further carried out. However, It is expected that, in high-insolation areas where large-scale ground storage is adaptable, solar system demonstrated in the research could be economically competitive and promisingly disseminate over various application areas.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.5B no.1
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• pp.57-62
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• 2005

Grid-connected photovoltaic (PV) systems were installed and monitored at the field demonstration test center (FDTC) in Korea in October 2002. Before long-term field testing of installed PV systems, the performances of PV components were evaluated and compared through short-term performance tests of each of the PV system components such as power conditioning system and PV module under standard test conditions. A data acquisition system has been constructed for measuring and analyzing the performance of PV systems to observe the overall effect of environmental conditions on their operation characteristics. Performances of PV systems have been evaluated and analyzed not only for component perspective (PV array, power conditioning unit) but also for global perspective (system efficiency, capacity factor, electrical power energy) by review of the field test and loss factors of the systems. These results indicate that it is highly imperative to develop an optimum design technology of grid connected PV systems. The objective of this paper is not only to evaluate and analyze the performance of domestic PV systems application through long-term field testing at FDTC but also to develop evaluation, analysis and optimum technology for long-term stability and reliability of grid-connected PV systems in Korea.

• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.245-248
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• 2000

This paper presents the test and operation results of the domestic demonstration of the reactive power compensation device called STATCOM (STATic COMpensator). The object of the paper is to describe the reliability of the unit based on the extensive operation databases. By controlling reactive power, the technology offers utilities the opportunity for increased efficiency and their capabilities will permit transmission planners make the best use of their existing transmission resources STATCOM is a custom power device in a way and can be used in a similar way for the dynamic compensation of power transmission systems, mitigation of voltage flicker and improving the power factor. It is shown that the STATCOM has clear advantages in areas such as: mitigation of voltage flicker and improving power factor.