One embodiment of the invention includes a method for extending an object-oriented programming language to include support for a shading language vector data type. The crown portion is provided with a thickness-reduced part having a thickness of from 0. Grouping can also be employed by an account owner to facilitate efficient sharing of monitoring data to many recipient accounts. A reference relational expression is set on the basis of myoelectric potentials measured in a first motion and a motion variable corresponding to the first motion.