Secondly, User cannot obtain enough information of object data, and cannot make sure the character of mutual objects because of actually complicated Object and relatively simple object expression in UML activity diagram;

• 第二，现实世界业务过程涉及的对象数据十分复杂，但是UML活动图的对象语义却非常简略，用户基本上无法从UML活动图中获取关于对象数据的信息，也不能确定参与交互的对象的特征。