Abstract: 

In the last decade design patterns have proven to be successful reuse
artifacts. However, the fact of being described in an informal fashion
limits tool support and their correct usage. This seminar describes an
updated version of Balanced Pattern Specification Language (BPSL), 
which uses Temporal Logic of Actions (TLA) as a formal basis to specify 
the structural as well as behavioral aspects of the most abstract yet generic
form of patterns. This was achieved by using temporal relations, which are
mathematical relations defined between objects of classes participating in
the pattern as TLA flexible variables. At the next level of abstraction
temporal relations can be validly refined using implementation-level TLA
variables.