  Using probabilities in the formal-methods-based development of
safety-critical software has quickened interests in academia and industry. We
address this area by our model-driven engineering method for reactive systems
SPACE and its tool-set Reactive Blocks that provide an extension to support the
modeling and verification of real-time behaviors. The approach facilitates the
composition of system models from reusable building blocks as well as the
verification of functional and real-time properties and the automatic
generation of Java code.
  In this paper, we describe the extension of the tool-set to enable the
modeling and verification of probabilistic real-time system behavior with the
focus on spatial properties that ensure system safety. In particular, we
incorporate descriptions of probabilistic behavior into our Reactive Blocks
models and integrate the model checker PRISM which allows to verify that a
real-time system satisfies certain safety properties with a given probability.
Moreover, we consider the spatial implication of probabilistic system
specifications by integrating the spatial verification tool BeSpaceD and give
an automatic approach to translate system specifications to the input languages
of PRISM and BeSpaceD. The approach is highlighted by an example.
