UML has become the standard object-oriented analysis and design language in software industry. However UML lacks a precise semantics that hinders error detection in the early stages of system development. Even worse, there is no clear definition of consistency criteria among various UML notations, and there are few examples of illustrating the use of various notations together. In this paper, we present an approach of using Hierarchical Predicate Transition Nets (HPrTNs) to define and integrate UML statechart diagrams and collaboration diagrams. Our approach establishes a basis for relating various UML models together and for carrying out formal analysis.
