CROSSWALK LAMP CONTROL SYSTEM AND CONTROL METHOD THEREOF
CAR NAVIGATION SYSTEM AND NAVIGATING METHOD USING THE SAME
Friction Resistance Reduction Apparatus using External Air and Stepped Hull Vessel having the Same
FRICTIONAL RESISTANCE REDUCING DEVICE USING EXTERNAL AIR, AND STEPPED BOAT HAVING SAME
Friction Resistance Reduction Apparatus using Exhaust Gas and Stepped Hull Vessel having the Same