Deciding an appropriate level of abstraction, which would enable a model to answer some questions accurately while maintaining a reasonable level of complexity, is considered the most critical challenge in the modeling field in general. This thesis aims at presenting a new general approach for tackling the level of abstraction problem. The approach is investigated methodologically and practically. In the methodological part, a formalism of dynamic systems defining model components that form targets of abstraction is presented. A classification of the main categories of abstraction...