Broadly speaking, there are two ways to represent functionalities.  The first approach provides an extensive ontology of functions where each class in the ontology corresponds to a class of homogeneous functionalities. ...   Amazon, for example, may advertise itself as a Bookselling service.

The second way to represent capabilities is to provide a generic description of function in terms of the state transformation that it produces.

似乎楼主刚刚进入这个领域啊，需要看的东西可能会有不少呢。