This volume contains the proceedings of FORTE 2008, 28th IFIP WG6.1 - ternational Conference on Formal Techniques for Networked and Distributed Systems. FORTE 2008 was held at the Campus Innovation Center in Tokyo, Japan during June 10-13, 2008. FORTE denotes a series of international wo- ing conferences on formal description techniques applied to computer networks and distributed systems. The conference series started in 1981 under the name PSTV. In 1988 a second series under the name FORTE was set up. Both - ries were united to FORTE/PSTV in 1996. In 2001 the conference changed the name to its current form. Recent conferences of this long series were held in Berlin (2003), Madrid(2004), Taipei(2005), Paris(2006), and Tallinn(2007). As in the previous year, FORTE 2008 was collocated with TESTCOM/ FATES 2008: the 20th IFIP International Conference on Testing of Com- nicating Systems (TESTCOM) and the 8th International Workshop on Formal Approaches to Testing of Software (FATES). The co-location of FORTE and TESTCOM/FATES fostered the collaboration between their communities. The commonspiritofboth conferenceswasunderpinnedby jointopening andclosing sessions, invited talks, as well as joint social events.

This book constitutes the refereed proceedings of the 27th IFIP WG 6.1 International Conference on Testing Software and Systems, ICTSS 2015, held in Sharjah and Dubai, United Arab Emirates, in November 2015. The 14 revised full papers and 4 short papers presented were carefully reviewed and selected from 42 submissions. The papers are organized in topical sections on model based testing, test derivation methods, monitoring and fault localization, model and system testing, and real-time systems.