Dogs are pack animals and Korean Jindos were trained to hunt in packs. They need companionship. If you see that they are going a little stir crazy, why not call up one of your friends and arrange a play date? Your dog will get to leave the house for a bit and you will get to spend some time with a friend too.
When playing catch has gotten old, or your dog needs a bit more exercise, it is time to take out the old Frisbee. Your dog will be running after that fluorescent disk and giving everything to catch it in time. They will burn off all their excess energy while you get to stand in one spot.