This work was supported by the National Research Founda- tion (NRF) grants (2013R1A1A2057784, 2012R1A2A2A02013289), with the main calculations carried out by the Supercomputing Cen- ter/Korea Institute of Science and Technology Information with supercomputing resources including technical support (KSC-2013- C1-012). This work was also supported by the Korea Ministry of Environment as ‘GAIA Project’ (2012000550026).