Isolated nucleic acid and amino acid sequence for osteoclast-specific genes and proteins are provided. The floating body including a compartment filled with an uprising gas having a density lower than that of air. Movable angles of the respective joint units are widened, and the joint units are precisely controlled. The concentric windings include windings which are singularly located within slots, and windings that share slots with other windings. The method includes the steps of calculating a current target wheel speed of each rear wheel to be used based on an actual deceleration speed of at least one of the front wheels and a previous target wheel speed of each rear wheel; and controlling braking force on each of the rear wheels based on the thus calculated current target wheel speed. The compounds have the following structure :including stereoisomers, pharmaceutically acceptable salts and prodrugs thereof, wherein X, Y, R1 and R2 are as defined herein.