• Structural Engineering and Mechanics
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• v.85 no.1
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• pp.1-14
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• 2023

The use of functionally graded materials in applications involving severe thermal gradients is quickly gaining acceptance in the composite mechanics community, the aerospace and aircraft industry. In the present study, a refined sandwich plate model is applied to study the free vibration analysis of porous functionally graded material (FGM) sandwich plates with various distribution rate of porosity. Two types of common FG sandwich plates are considered. The first sandwich plate is composed of two FG material (FGM) face sheets and a homogeneous ceramic or metal core. The second one consists of two homogeneous fully metal and ceramic face sheets at the top and bottom, respectively, and a FGM core. The displacement field of the present theory is chosen based on nonlinear variations in the in-plane displacements through the thickness of the sandwich plate. The number of unknowns and equations of motion of the present theory is reduced and hence makes them simple to use. In the analysis, the equation of motion for simply supported sandwich plates is obtained using Hamilton's principle. In order to present the effect of the variation of the porosity distribution on the dynamic behavior of the FGM sandwich plates, new mixtures are proposed which take into account different rate of porosity distribution between the ceramic and the metal. The present method is applicable to study the dynamic behavior of FGM plates and sandwich plates. The frequencies of two kinds of FGM sandwich structures are analyzed and discussed. Several numerical results have been compared with the ones available in the literature.

• Structural Engineering and Mechanics
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• v.87 no.5
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• pp.461-473
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• 2023

This study aims to solve for nonlinear cylindrical shell systems with a semi-analytical and numerical approach implementing the P-T method. The procedures and conditions for such a study are presented in practically solving and analyzing the cylindrical shell systems. An analytical model for a nonlinear thick cylindrical shell (TCS) is established on the basis of the stress function and Reddy's higher-order shear deformation theory (HSDT). According to Reddy's HSDT, Hooke's law in three dimensions, and the von-Kármán equation, the stress-strain relations are developed for the thick cylindrical shell systems, and the three coupled nonlinear governing equations are thus established and discretized as per the Galerkin method, for implementing the P-T method. The solution generated with the approach is continuous everywhere in the entire time domain considered. The approach proposed can also be used to numerically solve and analyze the nonlinear shell systems. The procedures and recurrence relations for numerical solutions of shell systems are presented. To demonstrate the application of the approach in numerically solving for nonlinear cylindrical shell systems, a specific nonlinear cylindrical shell system subjected to an external excitation is solved numerically. In numerically solving for the system, the present approach shows higher efficiency, accuracy, and reliability in comparison with that of the Runge-Kutta method. The approach with the P-T method presented is practically sound especially when continuous and high-quality numerical solutions for the shell systems are considered.

• Korea Journal of Hospital Management
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• v.28 no.3
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• pp.68-86
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• 2023

Purpose: The purpose of this study is to explore the relationship between corporate entrepreneurship and organizational effectiveness among employees of medical institutions. In addition, we aim to investigate the mediating effect of motivation to participate in the In-house Innovation & Start-up Contest and the moderating effect of support from a dedicated organization. Methodology/Approach: A survey was conducted on participants in the 3rd in-house contest held in 2023 at Granum Sinapis Center of Seoul St. Mary's Hospital. A total of 122 people responded to the survey. The collected data were analyzed PLS-SEM(Partial Least Squares-Structural Equation Model) using SmartPLS 4.0 program. Findings: First, 'Corporate entrepreneurship' had an effect on 'Participation motivation in in-house contest'. Second, 'Corporate entrepreneurship' had an effect on 'Organizational Effectiveness'. Third, 'Participation motivation in in-house contest' mediated the relationship between 'Corporate entrepreneurship' and 'Organizational Effectiveness'. And last, 'Support from a dedicated organization' had no moderating effect on the relationship between 'Corporate entrepreneurship' and 'Organizational Effectiveness'. Practical Implications: Since the dedicated organization is in the early stages of operation, there may be no moderating effect on organizational effectiveness. If follow-up research is conducted after the dedicated organization's system has been supplemented, the moderating effect may appear differently.

• Journal of Microbiology and Biotechnology
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• v.33 no.8
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• pp.1013-1022
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• 2023

Arbuscular mycorrhizal fungi (AMF) are widespread soil endophytic fungi, forming mutualistic relationships with the vast majority of land plants. Biochar (BC) has been reported to improve soil fertility and promote plant growth. However, limited studies are available concerning the combined effects of AMF and BC on soil community structure and plant growth. In this work, a pot experiment was designed to investigate the effects of AMF and BC on the rhizosphere microbial community of Allium fistulosum L. Using Illumina high-throughput sequencing, we showed that inoculation of AMF and BC had a significant impact on soil microbial community composition, diversity, and versatility. Increases were observed in both plant growth (the plant height by 8.6%, shoot fresh weight by 12.1%) and root morphological traits (average diameter by 20.5%). The phylogenetic tree also showed differences in the fungal community composition in A. fistulosum. In addition, Linear discriminant analysis (LDA) effect size (LEfSe) analysis revealed that 16 biomarkers were detected in the control (CK) and AMF treatment, while only 3 were detected in the AMF + BC treatment. Molecular ecological network analysis showed that the AMF + BC treatment group had a more complex network of fungal communities, as evidenced by higher average connectivity. The functional composition spectrum showed significant differences in the functional distribution of soil microbial communities among different fungal genera. The structural equation model (SEM) confirmed that AMF could improve the microbial multifunctionality by regulating the rhizosphere fungal diversity and soil properties. Our findings provide new information on the effects of AMF and biochar on plants and soil microbial communities.

• Journal of the Korea Society of Computer and Information
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• v.29 no.4
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• pp.135-143
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• 2024

This study investigates the impact of transactional leadership on job performance(team performance) and job satisfaction, with a focus on the mediating effect of job engagement. This study highlights the significance of contingent rewards and management by exception, components of transactional leadership, in motivating organizational members towards achievement and maintaining high performance levels. Through analysis, this research aims to demonstrate how transactional leadership affects employees' job engagement, subsequently influencing job performance and satisfaction. By understanding the role of job engagement as a mediator, organizations can adjust leadership styles and enhance job engagement, ultimately improving organizational performance and employee satisfaction. The findings suggest a composite approach to leadership, integrating both transactional and transformational elements, is more effective in fostering high job performance and satisfaction among employees. This study provides insights into developing strategies to boost job engagement and optimize leadership practices for better organizational outcomes.

• Journal of the Korean Applied Science and Technology
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• v.40 no.6
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• pp.1213-1224
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• 2023

The purpose of this study was to analyze the mediating role of self-efficacy in the relationship between the behavioral routines of beauty service workers on service performance and work performance. The subjects of the study were 311 beauty consumers in Seoul and Gyeonggi, and data were collected and analyzed using a structured questionnaire. For data analysis, descriptive statistics, confirmatory factor analysis(CFA), correlation analysis, structural equation model analysis(SEM), and mediating effect analysis using bootstrapping techniques were conducted. The conclusions drawn through a series of research procedures are as follows. First, the behavioral routines of beauty service workers were found to have a statistically significant positive(+) effect on self-efficacy, service performance, and work performance. Second, the self-efficacy of beauty service workers was found to have a statistically significant positive (+) effect on service performance and work performance. Third, the partial mediating effect of self-efficacy was shown in the relationship between beauty service workers' behavioral routines, service performance, and work performance.

• The Journal of the Korea Contents Association
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• v.22 no.8
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• pp.416-434
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• 2022

This study, for learners using online and offline tools, understood the structural relationship of user experience of smart learning app on continuous use intention through the technology acceptance model, and classified the learning type characteristics. In addition, based on the experience of using the smart learning app, we explored ways to improve the design of the user experience design for learning tools and contents. For this purpose, the usage perception of 84 middle and high school students of the developed smart learning learning app was investigated after using it for 2 months, and the data were analyzed using the PLS structural equation technique. The main results of this study are as follows. First, system and content user experience had a significant effect on perceived usability and perceived ease of use, and the effect on continued use intention through attitude was significant. Second, there was a significant difference in the effect of system user experience on perceived usefulness in multi-group comparative analysis and gender group. In the preferred learning group, it was the path from perceived ease of use and perceived usefulness to attitude and intention to continue using that showed a significant path difference. Third, as a result of classifying the most commonly used learning types by the multidimensional scale method, the types separated into low dimensions were found to be four types: offline sync type, online sync type, ubiquitous learning type, and self-direct learning type.

• Journal of Distribution Science
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• v.13 no.9
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• pp.81-93
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• 2015

Purpose - "Showrooming" refers to the phenomenon where a shopper visits a store to see and compare products but makes the purchase online at a lower price. Surveys on showrooming activities at home and abroad indicate that a significant number of consumers pursue showrooming activities. The advent of "showroomers," who engage in buying activities, hovering both on and offline, while selectively choosing sales channels to suit their needs, is powerful enough to erode the borders between channels and bring about seismic changes in the distribution industry. However, surprisingly, there has been no in-depth discussion on showrooming. This study seeks to theoretically investigate what impact personal characteristics have on showrooming preferences and attitudes in a multi-channel environment. Specifically, assumptions have been made that price perception, perceived performance risk, and trust in online shopping not only have a direct impact on showrooming attitudes but also indirectly affect it through the means of contact motivation. Research design, data, and methodology - To test the hypotheses, this study conducted a survey of male and female shoppers, ages 20 through 40s, who live in metropolitan areas, and have actively showroomed fashion items in the last six months. A clothing item usually purchased after a careful decision-making process was chosen as the target product of the study. The survey was conducted between October and November 2014, using a professional survey service provider. A total of 200 surveys were collected, of which 198 were used for analysis. Conceptual model Structural Equation Modeling (SEM) and Amos 18.0 were employed for data analysis and model verification. In addition, following the confirmatory factor analysis and measurement model analysis, the theoretical model that corresponds to the research model was analyzed. Results - Analysis results show that price perception, perceived performance risk, and trust in online shopping have a statistically significant and positive (+) impact on showrooming attitudes. In addition, in terms of the indirect influence of price perception and perceived performance risk on showrooming attitudes through means of contact motivation, price perception had a statistically significant and positive impact on means of contact motivation, whereas perceived performance risk did not have a statistically significant impact on it, with the relevant hypothesis rejected. Conclusions - These analysis results imply that the ultimate goal of consumers is to maximize their shopping benefits by selectively and strategically taking advantage of different channels in a complementary manner. This study presents many implications for distributors to encourage a deep understanding of showrooming consumers who have complicated consumption behaviors and to build channel integration strategies. This study has limitations in theoretical and practical implications. Therefore, subsequent studies need to focus on verifying that showrooming activities are based on reasonable and planned decisions by applying the theory of reasoned or planned behavior. In addition, the scope of the study should expand to include web showrooming, where consumers conduct product research online and purchase offline.

• Culinary science and hospitality research
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• v.21 no.3
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• pp.212-231
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• 2015

This study aims to understand the relationships between antecedents (recognition, empowerment, fair rewards, procedural justice(PJ), perceived organizational support(POS) and consequence(turnover intention(TI) of job engagement in a super deluxe hotel's F&B departments. Based on a total of 402 useful samples obtained for the empirical research, this study reviewed reliability and fitness of the research model and verified total 6 hypotheses with through the use of the AMOS statistical program. The hypothesized relationships in the model were tested simultaneously by using a structural equation model(SEM). The proposed model provided an adequate fit to the data, ${\chi}^2=668.894$(p<.001), df=373, CMIN/DF=1.794, GFI=.901, AGFI=.877, NFI=.928, CFI=.967, RMSEA=.044. The model's fit, as indicated by these indexes, was deemed satisfactory, and thus provided a good basis for testing the hypothesized paths. The results show that recognition, empowerment, fair rewards, PJ, and POS had a positive significant influence on job engagement. In addition, job engagement had a negative significant influence on TI. Through this it was confirmed that an optimized organization(working) environment reduced employees' turnover intention by increasing their job engagement level. Therefore, it is suggested that F&B departments at super deluxe hotels design various internal marketing programs from the perspective of efficient human resource management. Implications and limitations, as well as future research directions are also discussed.

• Culinary science and hospitality research
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• v.18 no.3
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• pp.72-89
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• 2012

This study aims to understand the influence of consumption value perceived by resort customers upon customer satisfaction and behavioral intention. Based on total 324 customers obtained from the empirical research, this study reviewed reliability and fitness of the research model and verified total 4 hypotheses with AMOS program. The hypothesized relationships in the model were tested simultaneously by using a structural equation model(SEM). The proposed model provided an adequate fit to the data, ${\chi}^2$=467.489(p<.001), df=326, CMIN/DF=1.434, GFI=.911, AGFI=.889, NFI=.881, CFI=.960, RMSEA=.037. The model's fit, as indicated by these indexes, was deemed satisfactory, thus it provided a good basic for testing the hypothesized paths. The result showed that the functional value(${\beta}$ .233, p<.01), social value(${\beta}$ .125, p<.05), emotion value(${\beta}$ .310, p<.001), epistemic value(${\beta}$ .144, p<.05) had a positive significant influence on customer satisfaction. Also, customer satisfaction(${\beta}$ .225, p<.01) had a positive significant influence on behavioral intention. The moderating effects by gender and marital status were found not to exist. Limitations and future research directions are also discussed.