• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.8
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• pp.115-122
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• 2020

This study aimed to improve the reliability of the assurance pressure of a gun barrel due to the difference between the US Standard and Korean Standard. In addition, the reliability was found to differ according to the maximum pressure of the Ammunition, so restrictions are expected. During the development of the new bullet, the maximum pressure of the bullet was approximately 3,000 psi higher than the assurance pressure of the gun barrel. To solve this problem, the reliability of the cannon was analyzed when the assurance pressure of the gun barrel increased. First of all, the technical data from overseas were reviewed to check for cases of increased assurance pressure, and tests were performed to determine if it could withstand high pressure through a verification firing test. Finally, the simulation analyzed the stability of the recoil buffer. The study found no abnormal results in all items, suggesting that an increase in the assurance pressure for a gun barrel was possible. This study is expected to be used as basic data for future reliability studies of similar equipment.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.206-212
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• 2004

This paper is application of System Assurance(SA) for the rolling stock. As railway systems become more complex, design teams are increasingly under pressure to deliver, design solutions, which integrate both technical and Systems Assurance(SA). Systems Assurance is the application of management methods and analysis techniques to ensure that a design meets Reliability, Availability, Maintainability and Safety (RAMS) criteria. It should be clearly understood that the intent of System Assurance is not just to provide analytical techniques as a metric on performance, but more importantly it should provide a management tool with which to co-ordinate and assure the whole design. System Assurance encompasses the ongoing requirement to consider safety, and RAM through each stage of a Project, from feasibility study through to commissioning and operation. If System Assurance is undertaken properly at feasibility study at the design stages of a Project, the benefits of such analyses can be significant in identifying potential problems early enough for action to be taken before manufacture or installation. At commissioning, RAMS demonstration activities are undertaken to validate the predictive and analytical techniques undertaken during the design.

• Journal of Korean Clinical Nursing Research
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• v.15 no.1
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• pp.133-147
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• 2009

Purpose: This study was conducted to construct evidence based clinical guidelines and to develop nursing process based performance measures for prevention and management of pressure ulcers, falls and pain. Method: Clinical guidelines were drafted through a comprehensive review of relevant literature, national guidelines and hospital protocols. The proposed guidelines were reviewed by a panel of experts and 90 hospital nurses, and refined on the basis of their suggestions. Nursing process based performance measures were developed based on the clinical guidelines and content validity was examined by surveys from 90 hospital nurses. Results: All items, except timetable for position change and pressure ulcer nursing record, in the guidelines for prevention and management of pressure ulcer were appropriate. Most items, except fall risk assessment tools, were appropriate for the guidelines of fall prevention. All other items, except the purpose of pain management, were appropriate for the guidelines of pain management. Performance measures developed in this study were acceptable as a tool to evaluate quality of nursing care. Conclusion: Nursing process based performance measures provide important indicators to monitor whether necessary nursing care is implemented and can be used as the primary resources to improve quality of nursing services.

• Structural Engineering and Mechanics
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• v.73 no.1
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• pp.27-35
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• 2020

In rail industry, noise reduction is a concern to decrease environmental pollution. The current study focuses on rail damper modeling and improvement of the model through validation with experimental results. Accurate modeling and simulation of rail dampers, specifically tuned rail dampers with layers interconnected by bolt joints, shall enable objective-oriented improvement of their design. In this work, to improve the damper model cone pressure theory is applied in the FE model and the sensitivity analysis is then applied to gradually improve the FE model. The improved model yields higher Modal Assurance Criterion (MAC) values and lower frequencies deviation.

• Plant Journal
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• v.17 no.1
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• pp.58-66
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• 2021

The government has recently come up with a policy to tighten regulations on air pollutant emissions due to public concerns over the emission of pollutants such as fine dust. The coal-fired power plant is speeding up the improvement of the performance of environmental facilities, and this paper deals with the cases of performance improvement by adding a catalyst to the 500 MW standard coal-fired power DeNox system, and examines the change in the performance factors according to the addition of catalysts and the efficiency of NOx removal. The DeNOx efficiency before and after improvement increased from 80% to 88%, and the conversion rate of SO2/SO3, ammonia slip which are performance factors satisfied the design assurance value, but exceeded the design assurance value for differential pressure. At the same time, the ammonia slip concentration and differential pressure items increased as the NOx removal efficiency increased, resulting in the need for management and improvement.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.4
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• pp.462-468
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• 2010

Fatigue crack growth caused by surface defects is one of the most important subjects for the evaluation and the assurance of safety in pressure vessels, piping systems, LPG/LNG fuel tank and other various structures. So, this paper aims to investigate the relationship between the surface roughness of fracture CT specimens and the moments on the specimen when doing fatigue test for the evaluation and the assurance of safety of structures from fatigue crack deconstruction. In this experiment, the CT specimens were loaded by a fatigue testing machine with changing loads until they are broken. The surface roughness of the fracture CT specimens was measured using 3D precise shape measuring equipment and digital holography. As a result of this study, It was identified that the average roughnesses are similar at the positions that has a same moments by comparing the results with the moments on the specimen according to the position.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.666-671
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• 2007

To acquire the safety along with durability of mechanical machinery products, we should consider the structural mechanics such as stress, deformation and dynamic vibration characteristics and identify those important aspects in the stage of preliminary design engineering. This cryogenic ball valve is used to transfer the liquified natural gas which temperature is $-196^{\circ}C$, supplied pressure is $168kg/cm^2$. For the cryogenic ball valve, the assurance of structural integrity and operability are essential to meet not only normal, abnormal loading conditions but also functionality during a seismic event. In this thesis, analytical approach and results using finite element analysis and computational method are herein presented to evaluate the aspects of structural integrity along with operability of cryogenic ball valve. In this study, we designed the high pressure cryogenic ball valve that accomplishes zero leakage by elastic seal at normal temperature and metal seal at high temperature.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.5C
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• pp.303-311
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• 2008

In the case of bi-directional high pressure pile load test with double-acting jack, the shortcomings of bi-directional pile load test with single-acting jack could be solved, low-cost of test could be sure, the limits of loading capacity could be overcome and quality assurance of service plie could be confirmed. In this study, to confirm the stability, the reliability and the application of bi-directional high pressure pile load test with double-acting jack, the calibration test for high pressure oil jacks, the length of high pressure hose and tunable high pressure pipe system were performed. As a result, credibility was very high because the reliability of test results was approached at about 1.0.

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.5
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• pp.68-75
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• 2010

The one of the major problems in the development of PEMFC was regarding to the assurance of sealing on stack. The failure on the sealing creates the problems of fuel leakage, mixing, internal combustion, damage on parts and can be a direct reason for the degrading the efficiency of fuel cell. This paper studies on the analytical approach for improving the contacting pressure distribution on the gasket at the evaluation on the sealing of fuel cell stack. So, the assembly analysis on multi layered fuel cell stack was performed. The research on the simplification of finite element model was performed for three dimensional analysis at the multi layered state. The improved contact pressure distribution was obtained through the case studies on gasket for better sealing. In addition, the number of the cell was determined for the effective analysis and the structural characteristics were evaluated based on this research.

• Journal of Korean Clinical Nursing Research
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• v.16 no.3
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• pp.5-23
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• 2010

Purpose: This study was conducted to determine the validity and reliability of performance measurement tools based on the nursing process for prevention and management of pressure ulcers, falls and pain. Methods: The performance measurement tools were reviewed by a panel of experts and refined on the basis of the panel's suggestions. The validity of the performance measurement tools was measured by surveying hospital nurses. The reliability of these tools was tested by having nursing experts use the tools in five nursing units to assess nursing performance in prevention and management of pressure ulcers, falls and pain. Results: The performance measurement tools in this study were found to be acceptable as tools to evaluate quality of nursing care in pressure ulcers, falls and pain. The reliability of the performance measurement tools was acceptable. Conclusion: These results indicate that the performance measurement tools developed in this study are valid and reliable instruments to monitor and improve quality of nursing care in prevention and management of pressure ulcers, falls and pain.