Executable task models

Current task modeling techniques have a shortcoming in that they only use the model at design time. This means that the information contained in the model has to be embedded into the application and makes the task model static. In this paper we propose using the task model at runtime, in order to simplify producing applications which adapt to the actions of the user. In particular, we extend the ConcurTaskTree (CTT) notation to allow dynamic execution of a task model. A key feature of our extension is that it gives semantics for the use of information exchange operators. Our second contribution is an implementation of our dynamic task model. We present a prototype application which shows how the interactions with the task model at runtime allow us to produce a dynamic and context aware user interface.