Apparatus includes a main body having a function of reducing performance of the apparatus during operation, an AC adapter which is connectable to the main body and supplies power to the main body from a commercial power source, and a rechargeable battery which is connectable to the main body and discharges to supply power to the main body. Such integration eliminates several assembly steps and therefore improves the optical misalignment tolerance for the optical link. The first body comprising includes first and second ends, the first end being for mounting on a robot component which is rotatable around a first axis; a. The method then performs kernel computations using successive list merging on the at least one identified column of the matrix and the support vector to derive a result vector, wherein the result vector is used in a data learning function.