Topics in Interoperability: System-of-Systems Evolution

This report examines how interoperable systems of systems evolve. It first considers several ways in which interoperability can be defined and then examines the notion of software evolution itself. Next, it considers how evolution occurs in interoperable systems of systems by discussing issues such as the motivation for and outcome of evolution. Finally, it proposes several properties of evolution that directly affect interoperability-in particular, how interoperability can be maintained as the individual systems evolve. This report is the first in a series of reports on interoperability. This series will consider the various properties and attributes of interoperability in an effort to determine how to measure the ability of a system to interoperate with other systems; predict the resources needed for successful interoperation; and discover techniques useful to achieving interoperability.