TA-LTL: Specifying Adaptation Timing Properties in Autonomic Systems

Increasingly, computer software must adapt dynamically to changing conditions. The correctness of adaptation cannot be properly addressed without precisely specifying the requirements for adaptation. In many situation, these requirements involve absolute time, in addition to a logical ordering of events. This paper introduces an approach to formally specifying such timing requirements for adaptive software. We introduce TA-LTL, a timed adaptation-based extension to linear temporal logic, and use this logic to specify three timing properties associated with the adaptation process: safety, liveness, and stability. A dynamic adaptation of interactive audio streaming software is used to illustrate timed temporal logic