Understanding ARIMA time series analysis with R (part 2)

In this post I describe the background and how-to for time-series analysis with more practical and advanced topics, non-stationary time-series (ARIMA) and seasonal time-series (Seasonal ARIMA), which is based on the basic idea (knowledge) in my previous post.
Through these posts (part1 and part2), you can shortly understand the outline for ARIMA time-series analysis.