Multi-level locks to control collaborative modeling sessions

Collaborative editing systems require mechanisms of control in order to make the collaboration more effective. The synchronous collaboration allows the notion of simultaneity; however, it demands more adequate perception elements. In the collaborative edition of UML diagrams where dependencies between their modeling elements do exist, it is necessary to apply a mechanism of control to support the edition of consistent models. In this work, we present a multi-level locking mechanism that automatically manages locks in the modeling elements of UML diagrams during a collaborative session. This paper also describes a controlled experiment conducted to study the use of the multi-level locking mechanism during collaborative modeling sessions, and the observations from the empirical data collected.