Object-oriented software development practices are being rapidly adopted within increasingly complex systems, including real-time and concurrent system applications. To address reliability issues with designing software architectures for these concurrent, time-critical system, this paper outlines an approach for integrating formalisms with state-of-the-practice object-oriented models expressed in UML. In this approach, colored Petri nets (CPNs) are used as an underlying representation of the dynamic object-oriented architecture. These CPNs are then used to provide a simulated functional flow of the architecture and to analyze the concurrent behavior. By applying the results from the CPN analysis to the original UML model, an engineer can enhance the quality of the design and thereby improve the reliability of the resulting system.