• Journal of the Computational Structural Engineering Institute of Korea
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• v.33 no.1
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• pp.63-72
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• 2020

The purpose of this study is to investigate the effects of the application of various numerical models and frequency contents of earthquakes on the performances of the reactor containment building (RCB) in a nuclear power plant (NPP) equipped with an advanced power reactor 1400. Two kinds of numerical models are developed to perform time-history analyses: a lumped-mass stick model (LMSM) and a full three-dimensional finite element model (3D FEM). The LMSM is constructed in SAP2000 using conventional beam elements with concentrated masses, whereas the 3D FEM is built in ANSYS using solid elements. Two groups of ground motions considering low- and high-frequency contents are applied in time-history analyses. The low-frequency motions are created by matching their response spectra with the Nuclear Regulatory Commission 1.60 design spectrum, whereas the high-frequency motions are artificially generated with a high-frequency range from 10Hz to 100Hz. Seismic responses are measured in terms of floor response spectra (FRS) at the various elevations of the RCB. The numerical results show that the FRS of the structure under low-frequency motions for two numerical models are highly matched. However, under high-frequency motions, the FRS obtained by the LMSM at a high natural frequency range are significantly different from those of the 3D FEM, and the largest difference is found at the lower elevation of the RCB. By assuming that the 3D FEM approximates responses of the structure accurately, it can be concluded that the LMSM produces a moderate discrepancy at the high-frequency range of the FRS of the RCB.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.7
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• pp.599-604
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• 2012

In this study, the safety of the driving gear reducer of ESW(essential service water) traveling sea water screen was evaluated through seismic analysis. Mode analysis of gear reducer was performed for reliability of analysis. Seismic analysis was performed in operating basis earthquake(OBE) and safe shutdown earthquake(SSE), which were applied as design condition using floor response spectrum( FRS). The maximum strain of gear reducer under OBE and SSE were 20.4 ${\mu}$ and 33.6 ${\mu}$, respectively. The maximum stresses were 2.42 MPa under OBE condition and 4.36 MPa under SSE condition, which were smaller than the allowable strength of material.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.731-736
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• 2011

In this study, the safety of the driving gear reducer of ESW traveling sea water screen was evaluated through seismic analysis. Mode analysis of gear reducer was performed for reliability of analysis. Seismic analysis was performed in Operating Basis Earthquake(OBE) and Safe Shutdown Earthquake(SSE), which was applied as design condition using Floor Respnse Spectrum(FRS). The maxsimum displacement of gear reducer under OBE and SSE were 0.0137 mm and 0.0241 mm, respectively. The maximum stress of gear reducer under OBE and SSE were 2.42 MPa and 4.36 MPa, respectively.

• Korean Journal of Computational Design and Engineering
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• v.8 no.2
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• pp.84-89
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• 2003

Axiomatic Design Theory is one of the most useful design methodologies which uses Functional Requirements(FRs) and Design Parameters(DPs) to make human designers more creative, to reduce the random search process, to minimize the iterative trial-and-error process, and to determine the best design among those proposed. In this research, we show how to develop a CAD system for an automotive rubber machinery using the axiomatic design approach to illustrate the effectiveness of the theory and we suggest a better way to select FRs and DPs in axiomatic design approach which can help designers to select them more effectively, objectively, and easily.

• Journal of the Korean Society of Propulsion Engineers
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• v.6 no.1
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• pp.1-11
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• 2002

The suitable turbulence model is found to be required in the course of establishing a proper analysis methodology for thermal stripping phenomena which are shown in strong temperature variation area such as reactors and propulsion devices. Three different turbulence models of $\kappa$-$\varepsilon$ model, modified $\kappa$-$\varepsilon$ model, and full Reynolds stress(FRS) model, are applied to analyze unsteady turbulent flows with temperature variation. Three test cases are selected for verification. These are vertical jet flows with water and sodium, and parallel jet flow with sodium. Analysis yields the conclusion that 3-D computation with FRS betters others. However, modified modeling is required to improve its heat transfer characteristic analysis. Further analysis is performed to find momentum variation effects on temperature distribution. It is found that the momentum increase results increase of fluid mixing and magnitude of temperature variation.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.13 no.3
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• pp.246-251
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• 2008

The conceptual design evaluation of Deep-Sea Manganese Nodule Miner(DSNM) based on Axiomatic Design was preformed. Functional Requirements(FRs) in functional domain and Design Parameters(DPs) in physical domain were embodied for the given concept design of DSNM. Interactions between FRs and DPs were sequentially analyzed from the first level hierarchy to the lower level hierarchy. The interactions were expressed as design matrices which showed the dependence or independence between FRs and DPs. The results showed that the design of DSNM was not a coupled one, but a decoupled. Finally, it was conceptually verified that DSNM was a good design satisfying the independence axiom of the Axiomatic Design.

• Journal of Nutrition and Health
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• v.41 no.4
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• pp.327-340
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• 2008

This study was designed to investigate the correlation between nutrition status and cardiovascular disease in type 2 diabetes patients with metabolic syndrome. The subjects were 66 patients and divided into Non MS (a group without metabolic syndrome, n = 37) and MS (a group with metabolic syndrome, n = 29). The percentage of patients accompanying metabolic syndrome was 43.9% and family history such as DM, skipping meal and eating speed were higher in MS (P < 0.05) The average values of BMI, body fat (%), waist circumference were significantly higher in patients of MS than that of Non MS. For hamatological values, MS showed higher FRS, HOMA-IR, LDL-Cholesterol, CRP. Percentage of FRS was 21.63% in MS that is relatively higher in comparison with 16.81% in Non MS. Moreover, the incidence of cardiovascular disease appeared 13.8% in MS that is higher than 2.7% in Non MS. The intake of sodium and vitamin E were higher, but the intake of fat, vitamin A and zinc were lower in MS than in Non MS. Close correlations were elucidated among FRS, occurrence of cardiovascular disease, weight, waist circumference, Total-Cholesterol, LDLCholesterol, sodium in both groups. In conclusion, cardiovascular disease risk factors would be higher in type 2 diabetes patients with metabolic syndrome and there were distinctive patterns that were associated with hamatological values, nutrition intake risk factors. This result should be considered when designing nutrition study and intervetion programs.

• Nuclear Engineering and Technology
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• v.54 no.1
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• pp.374-385
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• 2022

In order to investigate the application of 3D base-seismic isolation system in nuclear power plants (NPPs), comprehensive analysis of constitution and design theory for 3-dimensional combined isolation bearing (3D-CIB) was presented and derived. Four different vertical stiffness of 3D-CIB was designed to isolate the nuclear island (NI) building. This paper aimed at investigating the isolation effectiveness of 3D-CIB through modal analysis and dynamic time-history analysis. Numerical results in terms of dynamic response of 3D-CIB, relative displacement response, acceleration and floor response spectra (FRS) of the superstructure were compared to validate the reliability of 3D-CIB in mitigating seismic response. The results showed that 3D-CIB can significantly attenuate the horizontal acceleration response, and a fair amount of the vertical acceleration response reduction of the upper structure was still observed. 3D-CIB plays a significant role in reducing the horizontal and vertical FRS, the vertical FRS basically do not vary with the floor height. The smaller the vertical stiffness of 3D-CIB is, the better the vertical isolation effectiveness is, whereas, it will increase the displacement and the rocking effect of superstructure. Although the advantage of 3D-CIB is that the vertical stiffness can be flexibly adjusted, it should be designed by properly accounting for the balance between the isolation effectiveness and displacement control including rocking effect. The results of this study can provide the technical basis and guidance for the application of 3D-CIB to engineering structure.

• Journal of Korean Biological Nursing Science
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• v.24 no.3
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• pp.171-180
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• 2022

Purpose: The purpose of this study was to investigate the nutritional intake status, according to the risk of diabetic complications in Type 2 diabetes patients. Methods: This was a secondary data analysis study that included 83 patients. The nutritional intake was assessed, using 24-hour dietary recall. The risk of diabetic complications was measured, using the Framingham Risk Score (FRS) and Michigan Neuropathy Screening Instrument Questionnaire (MNSIQ). The nutritional intake was analyzed using the CAN-pro 4.0 program. Data were analyzed using descriptive statistics, Chi-square test, and Independent t-test, using the SPSS WIN 26.0 program. Results: The mean FRS and MNSIQ scores for the participants was 14.46± 4.09 and 2.30± 2.22, respectively. Thirty two participants (38.6%) were in the high-risk groups for cardiovascular disease and peripheral neuropathy. The participants consumed high amounts of grain and low amounts of vegetables, fruits, and dairy products when compared to the recommended intake. However, the nutritional intake did not differ according to FRS or MNSIQ levels. Consumption of vegetables and fruits were significantly different between high and low risk groups of MNSIQ. Conclusion: It is necessary to consider the composition of dietary intake to improve the imbalanced diet in Type 2 diabetes patients and prevent diabetic complications. Type 2 diabetes patients should reduce the intake of grains and sodium, and increase vegetable intake. More deliberate future studies are needed, to investigate the relationship between food intake and the risk status for diabetic complication.

• Korean Journal of Environmental Biology
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• v.37 no.4
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• pp.726-734
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• 2019

To understand the relationship between water velocity in a fishway and fish morphology, the fineness ratio of fish, expressed as the standard length to the body depth, was measured. The fineness ratios of fish groups belonging to Cyprinidae, Acheilognathinae, Centropomidae, and Centrachidae were relatively low. The FRs of other groups, excluding eel-shaped types of fish, were over 4.5, indicating streamlined structures. The fineness ratios of Korean fish were classified into three different types: type I was Bitterling-Carp group that favored a slow-flowing pool habitat(FRs ranged from 2.1 to 3.3), type II was the Chub group representing streamlined types (FRs FRs ranged from 3.7 to 5.2), and type III was the Smelt-Barbel fish group that preferred riffle-run habitats with high velocity (FRs is over 5.2). Fish abundance analysis of fish using the fishway during the experimental periods showed a relatively high abundance of both type II and III compared to type I. The FRs of the fish passing through fishway(velocity 0.5-1.0 m s^-1) ranged from 4.5 to 5.0, indicating that the fish using the fishway were mainly the streamlined type. As one of the standard fishways in Korea, the flow rate of the ice harbor type ranged from 0.2 to 2.6 m s^-1. The FR values of the fish groups using the fishway ranged from 4.3 to 5.0. In contrast, the flow rate measured in an artificial channel type of fishway (same as a natural type of fishway) ranged from 0.1 to 1.9 m s^-1 and the FR values for the fish groups using a natural type of fishway ranged from 3.3 to 5.3. The low FR values in natural fish are considered to be due to differences in the flow rates between the two types of fishways.