Can I use SmartThings Package in Korea?
The Z-wave frequency in Korea is 919-923 MHz while the SmartThings hub uses the US frequency 908.4 MHz.
The power to the hub is provided by a USB adapter which support 100-240V.
North or South?
Yes and no…
As @psfunatyo correctly pointed out, the Hub uses US frequency for Z-wave. I believe that Hubs are now (or will be soon) available for other frequencies, but you’ll want to make sure what is available first.
Now, that said, you COULD choose to use the US frequency and then just get all US frequency devices (outlets, switches, etc). This will be problematic as you’d need to verify that all are compatible with your voltage, but it would be possible.
A good discussion on the pro and cons of using US devices/hub can be found here