• Journal of the Computational Structural Engineering Institute of Korea
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• v.26 no.3
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• pp.207-212
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• 2013

APR1000(Advanced Power Reactor 1000) was developed to export 1000MW nuclear power plants by adding ADFs(Advanced Design Features) including 60 years design life, local frequency control operation, 0.3g SSE, etc. to OPR1000(Optimized Power Reactor 1000). In this paper, environmental fatigue analyses for the reactor vessel in APR1000 have been performed as per Reg. Guide 1.207. Outlet nozzle, which has a relatively high cumulative usage factor in the reactor vessel was evaluated and a structural integrity is maintained under the reactor coolant environment.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1098-1102
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• 2003

Vacuum vessel of the KSTAR(Korea Superconducting Tokamak Advanced Research) tokamak is a fully welded structure with D-shaped cross-section. According to the requirements of the physics design, sixteen horizontal ports, sixteen slanted ports, sixteen baking and cooling ports, and twenty-four top and bottom vertical ports are designed for the diagnostics, plasma heating, vacuum pumping, and baking and cooling. Bellows on these ports are used for flexible components to absorb the relative displacement due to the vacuum vessel thermal expansion and the electromagnetic force between the vacuum vessel and the cryostat ports. Fatigue strength evaluation was performed to decide the dimension of the bellows. In order to assure the quality of the bellows, a prototype bellows for the neutral beam injection port has been fabricated and tested prior to main fabrication. It was conformed that the prototype bellows has sufficient fatigue strength and vacuum reliability in the expected load conditions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.8
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• pp.4796-4801
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• 2014

To increase the riding comfort and running stability of articulated type high speed railway vehicles(HSRV), it is important that the gangway connections for the passenger car satisfied fire safety, sound proof and durability under triaxial angular displacement (rolling/yawing/pitching) modes. On the other hand, a domestic test standard on the durability of the rubber components has not been determined. In this study, the fatigue life was predicted using the results of the nonlinear finite element analysis and the fatigue properties. Moreover, a fatigue rig test of the component was constructed to examine the durability.

• Journal of Ocean Engineering and Technology
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• v.31 no.4
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• pp.299-307
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• 2017

The design of the mooring line to maintain the position of an offshore structure in rough marine environments is recognized as a very important consideration. Conventional fatigue evaluation of a mooring line was performed by considering the tensile force acting on the mooring line, but the mooring line broke after 238 days in the girassol area even though the expected fatigue life was expected to be longer. The causes of this event are known to be due to OPB/IPB (out-of-plane bending/in-plane bending) caused by chain link friction due to the excessive tensile strength of the mooring line. In this study, three models with different boundary conditions were proposed for fatigue analysis of a mooring line considering OPB/IPB. Interlink stiffness was calculated by nonlinear structure analysis and a stress concentration factor was derived. In addition, the sensitivity of interlink stiffness according to the magnitude of tensile force, large deformation effect, and coefficient of friction was analyzed, and the effect of critical elastic slip and bending moment calculation position on interlink stiffness was confirmed.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.3059-3066
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• 2008

It is reported that the life of generator stator windings is expected about 30 years and a leak and water absorption phenomena can be progressed by fatigue, vibration, and corrosion. The water-cooled generator stator windings which were operated over 15 years are over 20 units and the mechanical problems such as leak and water absorption were found in the generator stator windings. In this paper, the systematic mechanical integrity evaluation methods which are applied to the water-cooled generator stator windings within the country are introduced.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.126-131
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• 2001

Materials property data are necessary to secure the reliability of failure prevention techniques such as inspection and remaining life assessment of civil infrastructure and industrial facilities. However, there is no properly collected data in Korea, and those foreign data are hard to use because of the scattering of the sources, the difference of standards, etc. In this paper, materials property database system which has been constructed at Korea Research Institute of Standards and Science is introduced. Constructed database contains 145,000 numeric data of materials property for 600 kinds of metals and can be retrieved on the internet. The database system provides graphical user interface-based information searching functions necessary for the life evaluation and safety analysis.

• Korean Journal of Radiology
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• v.21 no.6
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• pp.633-646
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• 2020

We reviewed all studies assessing the health-related quality of life (HRQoL) in patients with hepatocellular carcinoma (HCC) between 2009 and 2018 (n = 45). Most studies assessed HRQoL as an outcome, and evaluated or compared the HRQoL of HCC patients depending on the type of treatment or stage of disease. HCC patients had a worse HRQoL than the general population, including in those with early-stage HCC. Patients commonly experienced pain, fatigue, sleep disturbance, distress, and lack of appetite, and these symptoms remained problematic even a few years after treatment. TNM classification of malignant tumors stage, tumor stage, presence of cirrhosis, being Asian, being female, living alone, or being unemployed were associated with a poor HRQoL. While recent studies have included a more diverse patient population, various topics, and different study designs, there were limited studies on supportive interventions. Given the increase in HCC cases and HCC survivors, addressing the HRQoL of HCC patients requires more attention.

• Journal of the Korean Society of Safety
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• v.34 no.5
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• pp.7-14
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• 2019

The type III vessel, which is used to store high-pressure hydrogen gas, is made by wrapping the vessel's liner with carbon fiber composite materials for strength performance and lightening. The liner seals the internal gas and the composite resists the internal pressure. The properties of the fiber composite material depends on the angle and thickness of the fiber. Thus, engineers should consider these various design variables. However, it significantly increases the design cost due to the trial and error under designing based on experience or experiments. And, for aluminum liners, fatigue loads due to using and charging could give a huge impact on the performance of the structure. However, fatigue failure does not necessarily occur in the position under the highest load in use. Therefore, for hydrogen storage vessel, fatigue evaluation according to design patterns is essential because stress distribution varies depend on composite layer patterns. This study performed an optimization analysis and evaluated a high-pressure hydrogen storage vessel to minimize these trial and error and improve the reliability of the structure, while simultaneously conducting fatigue assessment of all patterns derived from the optimization analysis process. The results of this study are thought to be useful in the strength improvement and life design of composite reinforced high-pressure storage vessels.

• International Journal of Highway Engineering
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• v.5 no.3 s.17
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• pp.1-9
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• 2003

This study was performed to evaluate the effect of various joint sealant on reducing the reflection cracking of asphalt concrete overlay on cement concrete pavement. The test method used was an accelerated reflection cracking test in shear mode, which was developed for evaluation of reflection cracking resistance of overlaid asphalt concrete in laboratory. The test results showed that use of joint sealants resulted in a significant reduction of reflection cracking. When sealant E was used, the fatigue life was the highest, with relatively larger horizontal deformation. When Sealant B was used, the dynamic stability was the highest with the smallest horizontal deformation. In general, the greater the tensile strength of sealant, the better the crack resistance of the mixture.

• Korean Journal of Biological Psychiatry
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• v.20 no.1
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• pp.6-11
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• 2013

Objectives There are only a limited number of studies on instruments assessing fatigue in university students, although fatigue exerts negative influences on their health and academic performances and fatigue-related complaints are more frequently reported in young adults than middle-aged adults. The aim of this study was to validate the 9-item Fatigue Severity Scale (FSS) among university students including both undergraduate and graduate students in South Korea. Methods A total of 176 university students completed a battery of self-report questionnaires, including the FSS, the Brief Fatigue Inventory (BFI), the Beck Depression Inventory-II (BDI-II), the Beck Anxiety Inventory (BAI), the Medical Outcomes Study Short Form 36 version 2 (MOS-SF36v2), and the Inclusion of Community in the Self Scale (ICS). The data were collected from February of 2012 to June of 2012. The reliability, convergent validity, divergent validity, and exploratory factor analyses were conducted to assess psychometric properties of the FSS. Results The mean FSS score was 3.20 (standard deviation = 1.43). The FSS demonstrated an excellent internal consistency (Cronbach's ${\alpha}$ = 0.93) and item-total correlations ranged from 0.56 to 0.90. Correlations of the FSS with the BFI (r = 0.71, p < 0.01), BDI-II (r = 0.54, p < 0.01), BAI (r = 0.46, p < 0.01), MOS-SF36v2 physical component summary (r = -0.28, p < 0.01), MOS-SF36v2 mental component summary (r = -0.55, p < 0.01), and ICS (Spearman's rho = -0.07, p = 0.33) showed acceptable convergent and divergent validity. Exploratory factor analysis defined one underlying factor (eigenvalue = 5.67) that explained 93.50% of the total variance. Conclusions To the best of our knowledge, this is the first study to investigate reliability and validity of the FSS in university students. The FSS exhibits good psychometric properties for evaluation of fatigue among university students in South Korea. Since the FSS is easy to administer, score, and interpret, it could be a useful tool in research and practice for assessing fatigue among university students.