  The Unified Software Development Process (USDP) and UML have been now
generally accepted as the standard methodology and modeling language for
developing Object-Oriented Systems. Although Agent-based Systems introduces new
issues, we consider that USDP and UML can be used in an extended manner for
modeling Agent-based Systems. The paper presents a methodology for designing
agent-based systems and the specific models expressed in an UML-based notation
corresponding to each phase of the software development process. UML was
extended using the provided mechanism: stereotypes. Therefore, this approach
can be managed with any CASE tool supporting UML. A Case Study, the development
of a specific agent-based Student Evaluation System (SAS), is presented.
