• New & Renewable Energy
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• v.19 no.4
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• pp.72-83
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• 2023

Only ground source heat pump units certified according to the regulations in Korea can be adopted in ground source heat pump systems. In this study, domestic and international standards and regulations for ground source heat pump units were investigated. Unlike ISO 13256-1~2, which is the international standard, KS B 8292~8294 for ground source heat pump unit only included rated test conditions. Therefore, it is necessary to supplement various test conditions to the KS B series, because its performance data, which is required to calculate the system's design capacity, is dependent on the change in entering water temperature. The difference between the coefficient of performance of the certified ground source heat pump units and the certified criteria changed significantly according to the operating mode, heat source, and load type, because the criteria increased by about 5% for all. Thus, it is highly suggested that the certification standards be revised while considering the product performance level and various conditions.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.18 no.1
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• pp.25-32
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• 2000

These days, the quantitative analysis of digital image by on-line image analysis system is being progressed actively, so the application of digital image is being groped in the safe test of construction. In this study, the synchronized 3D image acquisition and the system for processing that were established for analyzing the deflection of construction by using the acquired image from CCD camera. The reliability and the possibility of this established system are presented by deriving the accuracy of image analysis and the deflection of object through concrete loading test.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.11
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• pp.1413-1420
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• 2012

To predict the dynamics behavior, running stability, etc. of a railway vehicle and to understand its physical characteristics, analytical methods are used for the testing and manufacturing of a scale model along with numerical simulations in developed countries (England, France, Japan, etc.). The test of the dynamics characteristics of full-scale models is problematic in that it is expensive and time-consuming because an entire large-scale test plant needs to be constructed, difficulties are involved in the test configuration, etc. To overcome these problems, an analytical study involving dynamics tests and computer simulations using a scaled bogie model that applies the laws of similarity was carried out. In this study, we performed stability analysis on a 1/5 small scaled bogie for parameters such as the running speed and carbody weight by using an analysis model. Furthermore, we verified the reliability by using a small-scaled derailment simulator and examined the dynamic characteristic of the 1/5 small scaled bogie.

• Nuclear Engineering and Technology
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• v.27 no.5
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• pp.760-766
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• 1995

A general method is proposed for elastic stiffness analysis of the leaf type holddown springs using only the geometric data and Young's modulus of the springs. In this method, an engineering beam theory and Castigliano's theory are applied to elastic stiff analysis of the leaf type holddown springs. To show reliability and effectiveness of this method, the elastic stiffness from the proposed method is compared with test result and from the comparison, the unposed method has been proven to be effective for estimating the elastic stiffness of the leaf springs.

• Journal of Energy Engineering
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• v.21 no.1
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• pp.26-32
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• 2012

This study has been performed Thermal Shock test for analyze the cause of Power drop in PV(Photovoltaic) Module. Thermal Shock test condition was performed with temperature range from $-40^{\circ}C{\sim}85^{\circ}C$. One cycle time is 30min. which are consist of low and high temperature 15min. each other. The test was performed with total 500cycles. EL, I-V were conducted every 100cycle up to 500cycles. Mono Cell resulted in 8% Power drop rates in Bare Cell and 9% in Solar Cell. In the case of Multi Cell resulted in 6% Power drop rates in Bare Cell and 13% in Solar Cell. After Thermal Shock test, Solar Cell's Power drop resulted from surface damages, but in the case of Bare Cell's Power drop had no surface damages. Therefore, Bare Cell's Power drop was confirmed as according to leakage current increase by analysis of Fill Factor after Thermal Shock test. Also, Solar Cell's Power drop rates are higher than that of Bare Cell because of surface damages and consuming electric power increase. From now on, it should be considered that analyzed the reasons of Fill Factor decrease and irregular Power drop in PV module and Cell level using cross section, various conditions and test methods.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.1
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• pp.32-39
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• 2011

The purpose of VDR capsule is to maintain a stored information securely and retrievably in the extreme environment like voyage incident. This study shows the modellings, the analyses and the experiments of the survivability test of penetration, high and low temperature fire. The capsule housing is used to protect capsule against penetration and the influences of its thickness are studied by the modelling and analysis of penetration using LS-DYNA. The phase change material and thermal insulation material are used to protect capsule against high and low temperature fire test. The thermal characteristics of various volume ratios of phase change material to thermal insulation material were conducted. Also the tests were conducted to confirm the structural and thermal reliability.

• Journal of the Korea Institute of Military Science and Technology
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• v.7 no.4 s.19
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• pp.26-35
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• 2004

The ASTP is the standard of the assessment ASRP that is monitoring the performance, reliability and safety characteristics of the ammunition items. The ASTP used in domestic now has applied to US Army's grade system and grading criteria so that it cause some problems. To resolve these problems of ASTP, we surveyed both the quality level of production and the field management of ammunition, which compared with grade system and classification criteria. As a result of study, we changed grade system from four steps to three steps and applied the Korean Military Specifications and the Malfunction Criteria to the classification criteria of grades. We are looking forward to improving the reliability and effectiveness of ASRP assessment by simplifying grade system and generalizing grading criteria of ASTP.

• Journal of Ocean Engineering and Technology
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• v.14 no.4
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• pp.73-78
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• 2000

Presented are the estimation of the probability distribution of fatigue crack growth life and reliability assessment of structures by simulating material resistance to fatigue crack growth along a crack path. The material resistance is treated as a Weibull stochastic process. A non-Gaussian stochastic fields simulation method proposed by shimozuka, et al is applied with the statistical data obtained experimentally. Test results are obtained for $\delta K$ constant amplitude load in tension with stress ratio of R=0.2 and three specimen thicknesses of 6,12 and 18mm. This simulation method is useful to estimate the probability distribution of fatigue crack growth life and the smallest life.

• Fire Science and Engineering
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• v.14 no.2
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• pp.33-38
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• 2000

Flux, essentially used in soldering process of PCB (Printed Circuit Board) in electronics industry, contains IPA (Isopropyl alcohol) and methanol, which are highly inflammable and explosive. Hazard Chemical Controlling Law classified methanol as toxic material and Environmental Law classified methanol as VOC (Volatile Organic Compound). So there have been pressing needs of developing substitutes for the existing Flux. New solvent which is non-flammable and main component is DCP having same specific character of the existing Flux. It's been combirated with proper composition ratio adding stabilizer. As a result, it relieved working Environment Allowance thickness 200 ppm to 470 ppm, chance of not been soldered 0.083% to 0%, spread 85% to 87%, power saving resistance 1.0$\times$$10^{12}$$\Omega$ to 6.9$\times$$10^{12}$$\Omega$, which means a lot better than the existing Flux. Therefore, Flux confirmed the chance of improving productivity, safety, environment safety and quality. Also, Flux got a satisfied result after product quality test and product reliability test.

• Journal of the Korea Society of Computer and Information
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• v.25 no.2
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• pp.133-140
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• 2020

The IISS(Integrated Interface Storage System) software uses communication methods such as DSS(Data Sharing Service), UDP to perform the function of sending all messages from the Combat Management System to the analytical computer. Because IISS software handles all message used in the Combat Management System, the source code is large and has a highly dependent feature on message changes. Modification of software is a task that requires a lot of labor, such as series of software reliability test. so research has been conducted to reduce software development costs, including minimizing software modifications. In this paper, We study the method of messages receiving and architectural structure improvement to minimize reliance on message changes in the Combat Management System and improve the modifiability. Reduced message dependency by changing the way DSS and UDP protocols are communicated to Packet Sniffing. In addition, Factory Method Pattern were applied to improve the software design. Test comparing existing software and development elements have confirmed that the software has improved its modifiability and reuse.