Existing ADLs (architecture description languages) have an advantage of formally specifying the architecture of component-based systems. But ADLs have not come into extensive use in industries since ADL users should learn a distinct notation specific to architecture, and ADLs do not address all stakes of development process that is becoming diversified everyday. On the other hand, UML is a de facto standard general modeling language for software developments as UML provides a consistent notation and various supporting tools during the whole software development cycle. A number of researches on architecture modeling based on UML have been progressed. In particular, many research results have been introduced that specialize UML by its extension mechanism in order to explicitly represent core architecture concepts that UML does not fully support. In this paper, we examine architecture modeling elements that can be represented in UML2.0 and discuss how to extend and specialize UML2.0 in order to make it more suitable for representing architectures.