• Bulletin of the Korean Chemical Society
• /
• v.30 no.2
• /
• pp.423-428
• /
• 2009

The comparative study of three calix[4]heterocycles (calix[4]pyrrole, calix[4]furan, and calix[4]thiophene) has been theoretically performed by using high-level density functional theory (DFT) at the MPWB1K/6-311G$^{**}$//B3LYP/6- 311G$^{**}$ level. The effect of different hetero-atoms (nitrogen, oxygen, and sulfur) placed in the heterocycles on the conformational flexibility, thermodynamic stability order, cavity sizes, charge distributions, and binding propensities are examined. The thermodynamic stability differences between the conformers are found to be much greater in calix[4]pyrrole compared to those in calix[4]furan and calix[4]thiophene. Relatively larger NH group and higher dipole of a pyrrole ring in calix[4]pyrrole contribute to the higher energy barrier for the conformational conversions and relatively rigid potential energy surface compared to the case of calix[4]furan and calix[4]thiophene. The computational results herein provide theoretical understanding of the conformational flexibility and the thermodynamic nature which can be applied to understand the complexation behavior of the three calix[4]heterocycles.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
• /
• 2004.11a
• /
• pp.271-276
• /
• 2004

In this paper. dynamic behavior of the cracked beam under a moving mass is presented using the finite element method (FEM). Model accuracy is improved with the following consideration: (1) FE model with Timoshenko beam element (2) Additional flexibility matrix due to crack presence (3) Interaction forces between the moving mass and supported beam. The Timoshenko bean model with a two-node finite element is constructed based on Guyan condensation that leads to the results of classical formulations. but in a simple and systematic manner. The cracked section is represented by local flexibility matrix connecting two unchanged beam segments and the crack as modeled a massless rotational spring. The inertia force due to the moving mass is also involved with gravity force equivalent to a moving load. The numerical tests for various mass levels. crack sizes. locations and boundary conditions were performed.

• Journal of the Korean Geotechnical Society
• /
• v.23 no.9
• /
• pp.39-49
• /
• 2007

The load deformation behavior of the cap-pile-soil system is investigated, based on numerical analysis. Special attention is given to consideration of pile cap flexibility. Rigid pile cap analysis and flexible cap analysis were conducted for comparison. A numerical method that takes into account the coupling between the rigidities of the piles, the cap, and the column has been introduced to analyze the response of pile group supported columns. The prediction of the lateral loads and bending moments in the pile cap is much more conservative for a flexible cap than for a rigid cap.

• Korean Journal of Child Studies
• /
• v.36 no.3
• /
• pp.19-34
• /
• 2015

The purpose of this study was to explore the influence of marital satisfaction and depression of adoptive mother on the problem behaviors of adopted children and the mediating effects of parenting competency between them. Contextual variables such as family background and adoption-related characteristics were also included as control variables. The results of multiple regression analysis showed marital satisfaction had significant influence on the problem behavior of adopted child through flexibility of parenting competency, while depression was not significantly related to parenting competency of adoptive mother. Yet, maternal depression had direct influence on the problem behavior of adopted child. Based on the limitations of the study, suggestions for further study were made.

• Journal of the Korean Home Economics Association
• /
• v.37 no.4
• /
• pp.1-16
• /
• 1999

The objectives of this study are examine the variables effecting management behavior of home-band worker through empirical study. The data used for statistical analysis is 285 home-based worker. The statistical methods used for data analysis were frequencies, mean, t-test, multiple regression, factor analysis and path analysis. The major findings can be summarized as fellows. Home-based workers' various characteristics were statistically significant variable to management behavior. Home-based work income were higher for older women, no employ experience in out of home, lower age of children, business owner, lower time flexibility. In cause-effect model analysis that affects life satisfaction was related to work management, home management behavior and income. Based on the finds of the study, it was found that home-based work can be good alternative to induce married women to labour market if some problems are covered.

• International Journal of Precision Engineering and Manufacturing
• /
• v.9 no.3
• /
• pp.33-39
• /
• 2008

The effects of a double crack and tip masses on the dynamic behavior of cantilever beams with a moving mass are studied using numerical methods. The cantilever beams are modeled by applying Euler-Bernoulli beam theory. The cracked sections are represented by a local flexibility matrix connecting three undamaged beam segments. The influences of the crack, moving mass, and tip mass, and the coupling of these factors on the vibration mode and the frequencies of the double-cracked cantilever beams are determined analytically. The methodology provides a basis for analyzing the dynamic behavior of a beam with an arbitrary number of cracks and a moving mass.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 1997.04a
• /
• pp.211-218
• /
• 1997

Analysis of structures are usually executed under the assumption that connections are either ideally pinned joint or fully rigid joint. But in general all structures is connected under the semi-rigid connections. Semi-rigid connect ions have demerits that is simplification work on connection's behavior, moment-rotation relationships of connect ions , apprehension of nonlinear analysis etc. On the other hand there is merits that is improvements of serviceability, economic efficiency, construction in predicting real behavior frames. This study is to make model of connect ions by based on experimental study and after analysis on frames considering characteristics of semi-rigid connections. semi-rigid connection's influence on the behavior of structures and fundamental data on application of structures that is connected between S H S column and H beam is exhibited.

• Science of Emotion and Sensibility
• /
• v.26 no.2
• /
• pp.3-12
• /
• 2023

The present study examines the impact of COVID-19 anxiety on employees' psychological resources and behaviors, drawing on the conservation of resources theory. We also investigate whether flexibility in work contexts has a meaningful effect on employees' responses to the pandemic. A total of 284 working adults participated in an online survey consisting of self-reporting questionnaires that assessed levels of COVID-19 anxiety, vigor, innovative work behavior, and flexible working arrangements. The results showed that the level of vigor mediated the positive relationship between COVID-19 anxiety and innovative work behavior, and the perceived level of flexible working arrangements moderated this mediation effect positively. The findings highlight the importance of considering employees' psychological resources and work arrangements in managing the negative impact of COVID-19-related anxiety. This study provides theoretical and practical implications for organizations to better understand the psychological processes that employees undergo during a crisis. Further research on diverse work settings and cultural backgrounds is needed to expand on the present findings.

• International Journal of Internet, Broadcasting and Communication
• /
• v.15 no.4
• /
• pp.134-141
• /
• 2023

As robotic technology expands into various fields, robots need to execute some complicated tasks in diverse environments. However, the previous robotic software solutions were limited to independent systems. We can not adapt to diverse functionalities and environments. This makes it hard to provide rapid and effective services and leads to costs and losses in the development process. To overcome these problems, we propose a robot software framework with behavior trees based on ROS2. This framework simplifies complex robot behaviors through behavior trees and makes it easy to modify, extend, and reuse robot behaviors. Furthermore, ROS2 standardizes connections between software modules, enhances the robot's flexibility, and enables independent development and testing of software. Our framework aims to provide a foundation for high-quality robot service provision by supporting the modularity, reusability, independent development, and testing required by intelligent robots that need to provide services in various environments.

• Journal of East-West Nursing Research
• /
• v.10 no.1
• /
• pp.75-85
• /
• 2004

The purpose of this study was to examine the effects of the stretching and recreation exercise including health education on physical flexibility and health behavior compliance of women in elderly. Subjects included 28 women elderly who were residents of H Dong, Dondae moon-Gu, Seoul. The treatment intervention was applied during total 8 weeks as 5 times/week for stretching exercise with 2 times/weeks for health education. Data collection were from February to April, 2004. SPSS Window program was used by aims of this study for data analysis. The results were as following: 1. 75 old age above (39.3%) was the most of age in subjects. None education (42.9%) was the most of subjects in this study. Perceived health state was the most as 71.4% in moderate and good health state. 2. Physical flexibility of both shoulder(right z=-4.301, p=,000)(left z=-4.306), both arm(right z=-3.623, p=.0001)(left z=4.111, p=.0001), heel on both ankle(right z=-3.472, p=.0001) (left z=956, p=.0001), both before food(right z=-4.205, p=.0001)left(z=4.191, p=.0001) and both knee(right z=-4.118, p=.0001)(left z=4.082, p=.0001) was increased after 8 weeks more than before stretching and recreation exercise including health education were done. 3. Health behavior compliance(z=-4.073, p=.0001) was significantly on the effect. Therefore, it is confirmed that stretching exercise included health education is an effective nursing intervention for physical, mental, and psychological health management in elderly. Accordingly, authors are proposing that variously effective health management exercise programs must be developed for elderly, at the same time, the application and following up on the programs will be more important in the future.