A disposable cover for a bumper block comprises a body member having a cavity and an opening for receiving the bumper block. The recombinant Ralstonia eutropha, which is prepared by introducing a gene of an enzyme converting lactate into lactyl-CoA and a gene of a polyhydroxyalkanoate synthase using lactyl-CoA as a substrate thereto, may be cultured, thereby efficiently preparing a lactate polymer and a lactate copolymer. The invention prevents malicious attack and operation of illegal users, which improves the security of information and property of the users. The read control data is transmitted to the electrical device, thereby controlling the electrical device. Methods of using the compositions for both diagnostic and therapeutic utilities are provided. An N\xd7M matrix of points corresponding to the received OFDM symbol block is formed.