• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.34 no.5
• /
• pp.519-525
• /
• 2010

The finite element (FE) method is generally used to model and simulate the physical behavior of large structures, such as passenger vehicles or aircraft. However, FE analysis involves a very large computation time and cost for developing the analysis model. Therefore, the vibration characteristics of large structural systems are often analyzed using the component mode synthesis (CMS) method, which is one of the substructure synthesis methods. In this study, the vibration characteristics of passenger vehicles are analyzed by using the substructure synthesis method. A passenger vehicle model, which includes a vehicle body, suspension systems, and a sub-frame, is presented. The physical components of the vehicle system are modeled as equivalent substructures using the Craig-Bampton method of CMS. The vibration characteristics, such as the natural frequencies and mode shapes and frequency response, of the vehicle system are determined. The effects of variations in some design parameters on the vibration characteristics of the full vehicle model are also investigated.

• Journal of Environmental Health Sciences
• /
• v.42 no.5
• /
• pp.302-313
• /
• 2016

Objectives: This study was conducted to assess environmental health status on a local scale using environmental health-related indicators. It demonstrated the possibility of using a structural equation model, a methodological approach to provide synthesized information. Methods: Eighteen indicators were selected from official statistical data published by local governments. Each environmental health-related indicator was classified according to the PSR (pressure-state-response) model. Aggregation methods were performed using principal component analysis and fuzzy sets. Results: The five principal components were classified through principal component analysis (PCA) and obtained eigenvalues >1.0 from the initial 18 indicators. The aggregated index was obtained by condensing the original information into two broad and simple categories through fuzzy sets. Conclusion: This could be useful in that the aggregation procedure may provide a basis for establishing environmental health policies and a decision-making process. However, the availability and quality of indicators, assessment of aggregation method bias, choice of weighted scores for indicators, and other factors should be examined in future studies.

• Journal of Families and Better Life
• /
• v.32 no.1
• /
• pp.133-150
• /
• 2014

This study is aimed at examining the employment preparation of Chinese migrant women and exploring measures to support their employment in a practical manner. To accomplish the objectives, in-depth interviews with 15 Han Chinese and Korean Chinese women, who represent the highest proportion in Korea, were conducted. Each interview lasted for about an hour and a half on average, and there were additional questionnaires and observations on vocational courses. Collected data was analyzed in 4 steps by utilizing the analysis methods suggested by Lichtman (the three C's of data analysis: codes, categories, concepts), which were transformed to fit the final data. The research findings are as follows. First, the fundamental reasons that Chinese migrant women seek employment in Korea are as follows: role model as a mother based on motherhood and the desire to be recognized as a member of society. Second, as for employment strategies, although all the respondents were only dependent on the referral of their acquaintances and national institutions, Han Chinese and Korean Chinese women had ambivalent attitudes toward each other. Third, they attributed the causes of unemployment to personal aspects such as the amount of effort made and luck, and social structural aspects, including employment instability and low acceptance of multi- cultural individuals. Fourth, the migrant women hoping for 'complete integration' in the future, suggested some practical employment support measures. Such measures should be established by comprehensively reflecting their reasons for getting a job, employment strategies, attributions of unemployment, and employment outlook, rather than as response measures to the low birth rate and aging issues in Korea.

• The Korean Journal of Emergency Medical Services
• /
• v.24 no.1
• /
• pp.7-24
• /
• 2020

Purpose: Emergency medical service (EMS) personnel are at high risk of spreading infection. In this study, we used the PRECEDE model to identify the knowledge, status, and barriers to infection control among Korean paramedics to provide basic infection control data. Methods: A total of 164 respondents were analyzed for the study. A questionnaire was administered and collected through an online self-response platform. Descriptive analysis, t-test, ANOVA, multiple regression, and logistic regression analyses were performed to determine infection control practices and associated factors using SAS 9.4. To identify the pathways and direct, indirect, total effects based on the PRECEDE model, we used AMOS 26.0. Results: Highly rated self-efficacy (OR 8.82, 95% CI: 3.23-24.09), awareness (OR 6.05, 95% CI: 2.06-17.72), and enabling factors (OR 3.23, 95% CI: 1.18-8.78) led to superior infection control. As a result of the structural model analysis, the highly rated enabling factors and awareness led to superior practice patterns. Conclusion: Practice is related to self-efficacy, awareness, and enabling factors; however, further research is needed to develop strategies for infection control. In particular, institutional arrangements are needed to improve the enabling factors. Improving infection control performance may lead to better infection control and enhanced protection of EMS personnel and patients against infection risks.

• Structural Engineering and Mechanics
• /
• v.53 no.5
• /
• pp.939-956
• /
• 2015

In this study, in order to propose an efficient model to predict the torque capacity of steel fiber reinforced concrete (SFRC) beams, the existing experimental data related to torsional response of beams is reviewed. It is observed that existing data neglects the effects of some parameters on the variation of torque capacity. Thus, an experimental research was also conducted to obtain the effects of neglected parameters. In the experimental study, a total of seventeen SFRC beams are tested against torsion. The parameters considered in the experiments are concrete compressive strength, steel fiber aspect ratio, volumetric ratio of steel fibers and longitudinal reinforcement ratio. The effect of each parameter is discussed in terms of torque versus unit angle of twist graphs. The data obtained from this experimental research is also combined with the data got from previous studies and employed in artificial neural network (ANN) analysis to estimate the ultimate torque capacity of SFRC beams. In addition to parameters considered in the experiments, aspect ratio of beam cross-section, yield strengths of both transverse and longitudinal reinforcements, and transverse reinforcement ratio are also defined as parameters in ANN analysis due to their significant effects observed in previous studies. Assessment of the accuracy of ANN analysis in estimating the ultimate torque capacity of SFRC beams is performed by comparing the analytical and experimental results. Comparisons are conducted in terms of root mean square error (RMSE), mean absolute error (MAE) and coefficient of efficiency ($E_f$). The results of this study revealed that addition of steel fibers increases the ultimate torque capacity of reinforced concrete beams. It is also found that ANN is a powerful method and a feasible tool to estimate ultimate torque capacity of both normal and high strength concrete beams within the range of input parameters considered.

• Journal of Microbiology and Biotechnology
• /
• v.28 no.9
• /
• pp.1554-1562
• /
• 2018

The type I interferons (IFNs) play a vital role in activation of innate immunity in response to viral infection. Accordingly, viruses have evolved to employ various survival strategies to evade innate immune responses induced by type I IFNs. For example, hepatitis E virus (HEV) encoded papain-like cysteine protease (PCP) has been shown to inhibit IFN activation signaling by suppressing K63-linked de-ubiquitination of retinoic acid-inducible gene I (RIG-I) and TANK-binding kinase 1 (TBK1), thus effectively inhibiting down-stream activation of IFN signaling. In the present study, we demonstrated that HEV inhibits polyinosinic-polycytidylic acid (poly(I:C))-induced $IFN-{\beta}$ transcriptional induction. Moreover, by using reporter assay with individual HEV-encoded gene, we showed that HEV methyltransferase (MeT), a non-structural protein, significantly decreases RIG-I-induced $IFN-{\beta}$ induction and $NF-{\kappa}B$ signaling activities in a dose-dependent manner. Taken together, we report here that MeT, along with PCP, is responsible for the inhibition of RIG-I-induced activation of type I IFNs, expanding the list of HEV-encoded antagonists of the host innate immunity.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.32 no.2C
• /
• pp.61-68
• /
• 2012

In general, verticality error necessarily occurs in marine pile foundation due to construction error or marine environmental effects. In marine structure, design by vertical load rather than horizontal load is dominant, but in the offshore wind turbine foundation, horizontal load is dominant. As the structure type that has dynamic movement by blade rotation, verticality error may have structurally significant effects. In this study, structural response feature of foundation and ground were analyzed according to verticality error of monopile foundation of 5MW offshore wind turbine. Marine environmental load was calculated per ISO standard and the margin of verticality error was calculated to be $L/{\infty}$(=0), L/300, L/200 and L/100. As a result of analysis, it was found that the maximum value of member force of the foundation with L/100 error increased about 7.2% compared to the monopile without verticality error.

• Journal of the Korean Society of Costume
• /
• v.66 no.2
• /
• pp.45-60
• /
• 2016

As a method to satisfy needs and emotions of consumers who pursue diversity, the use of Kitsch in the fashion industry has been increased. Previous studies on Kitsch fashion have focused on qualitative research on the characteristics of Kitsch product, and little empirical researches have been conducted on consumer attitude such as consumer response to Kitsch products and brand equity. Therefore, the purpose of this study are 1) to investigate comparisons of experiential values (i.e., Aesthetic, Amusing, Cultural) with Kitsch product moderated by consumers' characteristics (i.e., consumer uniqueness, fashion involvement), and 2) to explore the relationship between experiential values and brand equity. Factor analysis, reliability analysis, ANOVA, and structural equation model using SPSS 18.0 and AMOS 18.0 were used for the data analysis. 210 questionnaires were analyzed for this study. The results of this study were as follows. First, significant difference in aesthetic values of Kitsch products were shown. Kitsch Product with nostalgic characteristics has higher aesthetic values than others. Specifically differences in experiential values with Kitsch product were partially moderated by consumers' characteristics (i.e., consumer uniqueness, fashion involvement), Second, cultural value had a positive influence on brand awareness, while amusing and cultural values had a positive influence on brand image. Also aesthetic and amusing values had a positive influence on brand loyalty. Academic and business implications were discussed from this study.

• Composites Research
• /
• v.13 no.6
• /
• pp.23-29
• /
• 2000

The internal residual stresses within the multilayered structure with sharp interface induced by the difference in thermal expansion coefficient between the materials of adjacent layers often provide the source of failure such as delamination of interfaces etc. Recent development of the multilayered structure with functionally graded interface would be the solution to prevent this kind of failure. However a systematic thermo-mechanical analysis is needed for the customized structural design of multilayered structure. In this study, theoretical model for the thermo-mechanical analysis is developed for multilayered structures of the $Al-SiC_p$ functionally graded composite for electronic packaging. The evolution of curvature and internal stresses in response to temperature variations is presented for the different combinations of geometry. The resultant analytical solutions are used for the optimal design of the multilayered structures with functionally graded interface as well as with sharp interface.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.20 no.6
• /
• pp.703-713
• /
• 2011

In this study, to minimize trial and error in the design and manufacturing processes of a high-precision large-surface micro-grooving machine which is able to fabricate the molds for 42 inch LCD light guide panels, the effects of the structural deformation of the micro-grooving machine according to the positions of the X-axis, Y-axis and Z-axis feed systems were examined on the tool tip displacement errors associated with the machining accuracy. The virtual prototype (finite element model) of the micro-grooving machine was constructed to include the joint stiffnesses of the hydrostatic bearings, hydrostatic guideways and linear motors, and then the tool tip displacement errors were measured from the virtual prototype. Especially, to establish the prediction model of the tool tip displacement errors, which was constructed using the positions of the X-axis, Y-axis and Z-axis feed systems as independent variables, the response surface method based on the central composite design was introduced. The reliability of the prediction model was verified by the fact that the tool tip displacement errors obtained from the prediction model coincided well those measured from the virtual prototype. And the causes of the tool tip displacement errors were identified through the analysis of interactions between the positions of the X-axis, Y-axis and Z-axis feed systems.