Editorial

Richard Wiener, Editor- in-Chief

Dear Readers,

Sven Apel and Christian Kästner, our new columnists, have contributed their second column. Marcus Volter has contributed a Guest Column dealing with domain specific languages. I have contributed a column dealing with ant colony system heuristic algorithms and their C# implementation. In addition our other regular columnists Mahesh Dodani, Doug Lyon and John McGregor have contributed to this issue. Their work is greatly appreciated.

Our five feature length papers again deal with an unusal variety of subjects that I believe you will find interesting and useful. These include the mix of functional and object-oriented programming, model refactoring, metrics that focus on control flow paths and security specification in UML diagrams.