In a clean water test, the bubble diameter coming out through the circular diffusers was measured by photographic method and binary image analysis. Strong correlation was found between bubble diameter and superficial velocity. The depth of water has been added to existing experimental factors that include pore size and superficial velocity. By using dimensional analysis and multiple linear regression algorithm, a prediction model of bubble diameter was developed considering fluid properties and experimental factors including the depth of water. The developed model(EF-Model) was compared with the existing bubble diameter prediction models for the sample data. As a result of estimating the bubble diameter for the superficial velocity, the EF-Model has a lower RMSE and higher accuracy result than the existing models.

The overall phase velocity change of SAW for a n-Si thin layer on a YZ-LiNbO3 substrate is calculated considering mechanical and electrical perturbations in the case of low-kd limit. The mechanical perturbation is modified to include the dependence on electron concentration in Si. The variation of overall SAW velocity with electron concentration, layer thickness, and frequency show markedly different dependence from that of both mechanical and electrical perturbations. The rapid decreases of overall SAW velocity at low and high electron concentrations are attributed to the electrical perturbation and carrier concentration effect on mechanical perturbation respectively.

Recently, the research on critical infrastructures have been extended its boundary and some previous research analysed interdependency between infrastructures tried to suggest operation and management policy of the infrastructure. This highlighted the importance of systemic approach such as System Dynamics. But there still exist the limit to select the modelling component in terms of causality. In this study, convergent cross mapping was applied to time series variables in Songpa-gu and Gangdong-gu in Seoul, South Korea. Selected variables include operating variable of water supply system, floating population and meteorological variables and 330 observations were collected. The result shows that daily average temperature and floating population that are equivalent to mobile population influences to the daily water supply, and vice versa. Other weather factors such as average precipitation and wind speed showed little causality with the daily water supply. The influential factors of water supply system can be investigated with convergent cross mapping and the result can be utilized for the pre-process of other methodology such as LSTM in short-term water demand prediction. It is expected to collect more available data to improve this study further.