  Modal automata are a classic formal model for component-based systems that
comes equipped with a rich specification theory supporting abstraction,
refinement and compositional reasoning. In recent years, quantitative variants
of modal automata were introduced for specifying and reasoning about
component-based designs for embedded and mobile systems. These respectively
generalize modal specification theories for timed and probabilistic systems. In
this paper, we define a modal specification language for combined probabilistic
timed systems, called abstract probabilistic timed automata, which generalizes
existing formalisms. We introduce appropriate syntactic and semantic refinement
notions and discuss consistency of our specification language, also with
respect to time-divergence. We identify a subclass of our models for which we
define the fundamental operations for abstraction, conjunction and parallel
composition, and show several compositionality results.
