• Journal of Environmental Science International
• /
• v.26 no.3
• /
• pp.363-371
• /
• 2017

This study evaluates the adsorption properties of Sr ions in an aqueous solution of the synthetic zeolite (Z-Y1) prepared using coal fly ash generated from a thermal power plant. In order to investigate the adsorption characteristics, the effects of various parameters such as the initial concentrations of Sr ion, contact time, and solution pH were investigated in a batch mode. The Langmuir and Redlich-Peterson model fitted the adsorption isotherm data better than the Freundlich model. The maximum adsorption capacity of Sr ions, as determined the Langmuir model, was 181.68 mg/g. It was found that by varying the Sr ion concentration, pH, and temperature, the pseudo-second-order kinetic model describes the adsorption kinetics of the Sr ion better than the pseudo-first-order kinetic model. The calculated thermodynamic parameters of ${\Delta}H^0$ and ${\Delta}G^0$ showed that the adsorption of Sr ions on Z-Y1 was occurred through a spontaneous and an endothermic reaction. We found that the adsorption of Sr ions by Z-Y1 was more affected by pH than by temperature and Sr ion concentration.

• The Journal of Information Systems
• /
• v.26 no.3
• /
• pp.211-228
• /
• 2017

Purpose This study proposes a research model based on Expectation-Confirmation theory in order to investigate impacts of three variables(expectation confirmation, social interaction, and perceived usefulness) on continuous intention to uss SNS in MICE industry. Design/methodology/approach A survey approach was used in order to measure each latent variable in the research model. A total of 140 responses were collected from actual users of SNS in MICE industry. A structural equation modeling with SmartPLS 2.0 was conducted in order to analyze each relationship in the proposed research model. Findings The results indicated the expectation confirmation had a positive impact on the perceived usefulness, social interaction, and satisfaction. Second, perceived usefulness had a significant positive impact on satisfaction and continuous intention to use SNS in MICE industry. Thrid, social interaction had a positive influence on both satisfaction and continuous intention to use SNS in MICE industry. Finally, the relationship between satisfaction and continuous intention in SNS of MICE industry was fully supported.

• Journal of the Korean Society for Precision Engineering
• /
• v.22 no.10 s.175
• /
• pp.158-166
• /
• 2005

Pressurized gas pipeline is subject to harmful effects both of the surrounding environment and of the materials transmitted in them. In order to maintain the integrity, reliable assessment procedures including tincture mechanics analysis etc are required. Up to now, the integrity assessment has been performed using conventional deterministic approaches even though there are many uncertainties to hinder a rational evaluation. In this respect, probabilistic approach is considered as an appropriate method for gas pipeline evaluation. The objectives of this paper are to estimate the failure probability of corroded pipeline in gas and oil plants and to propose limited operating conditions under different types of leadings. To do this, a probabilistic assessment program using reliability index and simulation techniques was developed and applied to evaluate failure probabilities of corroded API-5L-X52/X60 gas pipelines subjected to internal pressure, bending moment and combined loading. The evaluation results showed a promising applicability of the probabilistic integrity assessment program.

• International Journal of Human Ecology
• /
• v.15 no.2
• /
• pp.69-80
• /
• 2014

Guided by the exchange model, altruistic model, intergenerational solidarity theory, and cultural contexts, this study explored the determinants of financial intergenerational transfers between older parents and adult children in South Korea. We examined 18,820 parent-child dyads by using random-effects models on the first wave of the Korean Longitudinal Study of Ageing (KLoSA) data. Findings showed that downward financial intergenerational transfers were consistent with the self-interest exchange model but upward transfers did not support microeconomic theories. Family solidarity theory was generally supported by downward transfers but geographical proximity was not positively associated with upward transfers. Lastly, cultural contextual variables such as marital status, birth order, and sex of a child were found to be significant. Parents tended to both provide and receive more financial support from unmarried children than from married children. Within the same marital status, the hierarchy existed in order of the first-born son, the second or later sons, and daughters when it came to downward financial transfers. Regarding upward financial transfers, the preference in order was more complicated. The findings of this study help in understanding the intergenerational financial transfers in the Korean context.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.35 no.3
• /
• pp.52-61
• /
• 2012

The design method for cumulative sum (CUSUM) control charts, which can be robust to autoregressive moving average (ARMA) modeling errors, has not been frequently proposed so far. This is because the CUSUM statistic involves a maximum function, which is intractable in mathematical derivations, and thus any modification on the statistic can not be favorably made. We propose residual-based robust CUSUM control charts for monitoring autocorrelated processes. In order to incorporate the effects of ARMA modeling errors into the design method, we modify parameters (reference value and decision interval) of CUSUM control charts using the approximate expected variance of residuals generated in model uncertainty, rather than directly modify the form of the CUSUM statistic. The expected variance of residuals is derived using a second-order Taylor approximation and the general form is represented using the order of ARMA models with the sample size for ARMA modeling. Based on the Monte carlo simulation, we demonstrate that the proposed method can be effectively used for statistical process control (SPC) charts, which are robust to ARMA modeling errors.

• Structural Engineering and Mechanics
• /
• v.27 no.2
• /
• pp.199-222
• /
• 2007

Composite laminated structures supported on elastic foundations are being increasingly used in a great variety of engineering applications. Composites exhibit larger dispersion in their material properties compared to the conventional materials due to large number of parameters associated with their manufacturing and fabrication processes. And also the dispersion in elastic foundation stiffness parameter is inherent due to inaccurate modeling and determination of elastic foundation properties in practice. For a better modeling of the material properties and foundation, these are treated as random variables. This paper deals with effects of randomness in material properties and foundation stiffness parameters on the free vibration response of laminated composite plate resting on an elastic foundation. A $C^0$ finite element method has been used for arriving at an eigen value problem. Higher order shear deformation theory has been used to model the displacement field. A mean centered first order perturbation technique has been employed to handle randomness in system properties for obtaining the stochastic characteristic of frequency response. It is observed that small amount of variations in random material properties and foundation stiffness parameters significantly affect the free vibration response of the laminated composite plate. The results have been compared with those available in the literature and an independent Monte Carlo simulation.

• Journal of Families and Better Life
• /
• v.24 no.1 s.79
• /
• pp.83-102
• /
• 2006

The purpose of this study is to examine the effects of the divorce process on post-divorce adjustment. This study specifically examines the effects of the pre-divorce marital quality, perceived barriers to divorce at the time of considering divorce, and the level of everyday stress after divorce on post-divorce adjustment of men and women focused on gender differences. Data gathered from 147 men and 208 women living in Seoul and Gyeonggi province were analyzed for this study. The major findings are as follows. First, pre-divorce marital quality, perceived barriers to divorce at the time of considering divorce, and the level of everyday stress after divorce, have both positive and negative effects on post-divorce adjustment of divorced men and women depending on the stages of divorce process. Second, the relationship between various aspects of divorce process and adjustments differ according to the sub-dimension of post-divorce adjustment. Third, divorce process functions differently for divorced men and women. The results show the importance of considering the divorce process, including both pre-divorce and post-divorce circumstances in order to have a good understanding of post-divorce adjustment of men and women.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.14 no.1
• /
• pp.93-103
• /
• 1994

Two beam/column elements are developed in order to analyze the geometric nonlinear plane irames including the effects of internal hinge and transverse shear deformation. In the case of the first element (finite segment method), tangent stiffness matrix is derived by directly integrating the equilibrium equations whereas in the case of the second element (finite element method) elastic and goemetric stiffness matrices are calculated by using the hermitian polynomials including the effects of internal hinge and shear deformation as the shape function. Numerical results are presented for the selected test problems which demonstrate that both elements represent reliable and highly accurate tools.

• Korean Journal of Childcare and Education
• /
• v.13 no.1
• /
• pp.185-200
• /
• 2017

Objective: This study was conducted to investigate the effects of early childhood teachers' teaching beliefs, mathematics teaching efficacy, and pedagogical content knowledge of mathematics on their teaching intention of mathematics. Methods: A total of 266 early child teachers in Busan participated in this study. They completed a set of question naires which consisted of questions about teaching beliefs, mathematics teaching efficacy, pedagogical content knowledge of mathematics, and the teaching intention of mathematics. The collected data were analyzed using the SPSS program. Results: First, we observed several positive correlations among the four variables. Second, we found that early childhood teachers' constructive teaching beliefs, mathematics teaching efficacy, and pedagogical content knowledge of mathematics had effects on their teaching intention of mathematics. The knowledge about teaching-learning methods for mathematics among the subcategories of pedagogical content knowledge of mathematics was observed as the strongest predictor for the teachers' teaching intention. Conclusion: We need to take more interest in the pedagogical knowledge about teaching-learning methods of mathematics in teacher training courses in order to enhance teachers' teaching intention of mathematics. As a result, this will makea contribution to high quality math education for young children.

• The Journal of the Korea Contents Association
• /
• v.7 no.7
• /
• pp.133-143
• /
• 2007

The object of this study is to empirically analyze the effects of information support quality and service quality on service satisfaction of department store. To investigate the purpose of this study, literature review and survey were conducted. for statistical analysis, factor analysis, analysis of variance(ANOVA), and regression in order by the contingency grouping method were used. In conclusion of this study are as follows First, The regression analysis had effects on information support quality and service satisfaction. Second, The Analysis of variance(ANOVA) and regression had effects on information support quality and service satisfaction as service quality factors. Result, The information support accuracy and service quality had additional effect about customer relation.