Objectives: This study's aim was to examine the importance of preschoolers' social competence and the effects of smart-media (smartphones, tablet PCs) use on the development of their social competence. Methods: Questionnaires were used to measure preschoolers' social competence, smart-media usage time, parents' media literacy, and smart-media mediation. SPSS 22.0 and AMOS 22.0 were used to analyze the collected data while descriptive statistics, t-test, Pearson's correlation, structural equation modeling, and bootstrapping were adopted for data analysis. Results: First, parents' media literacy had significant effects on their smart-media mediation, which in turn had indirect effects on preschoolers' smart-media usage time. Second, preschoolers' smart-media usage time had a significant effect on their social competence. Additionally, their parents' smart-media mediation indirectly affected their social competence through their smart-media usage time. Conclusion: The findings highlight the importance of parental roles in mediating and regulating preschoolers' use of smart-media to promote their healthy social development.

The GMA welding process involves large number of interdependent variables which may affect product quality, productivity and cost effectiveness. The relationships between process parameters for a vertical weldment and mechanical properties are complex because a number of process parameters are involved. To make the verticalposition welding, a method that predicts bead geometry and accomplishes the desired mechanical properties of the weldment should be developed. In addition, a reliable welding process and conditions must be implemented to reduce weld structure failure. In this study, the welding process analysis of investigates the interaction between the heat input and welding parameter(Welding current, Arc voltage, Welding speed) for predicting the weldment hardness.

The automatic welding systems, have received much attention in recent years, because they are highly suitable not only to increase the quality and productivity, but also to decrease manufacturing time and cost for a given product. Automatic welding work in semiconductor or space industry to be carried out in pipe line and butt joint mostly and plasma arc welding(PAW) is actively applied. To get the desired quality welds in automated welding system is challenging, a mathematical model is needed that has complete control over the relevant process parameters in order to obtain the required mechanical properties. However, In various industries the welding process mathematical model is not fully formulated for the process parameter and on the welding conditions, therefore only partial variables can be predicted. Therefore, this paper investigates the interaction between the welding parameters and mechanical properties for predicting the weld bead geometry by analyzing the S/N ratio.