User requirements and resource control for cooperative multimedia applications

Mobile computing: operational models, programming modes and software tools

“…Example 2: Suppose we want to make a flight reservation using a mobile transaction. Here one needs to have the following workflow [1], [2], [5], [25] : select a suitable airline that offers cheaper fares, ensure there is vacancy, and make an advanced booking (that is to be confirmed later). These individual steps are really not traditional transactions, but well-defined program pieces that can be carried out concurrently and may need to follow a predefined partial order to satisfy certain predicates (such as seat availability) invariant criteria (number of seats cannot exceed the size of aircraft) and synchronization ( one step requires the completion of other step) .…”

“…A workflow [1], [2], [5], [25] is a collection of tasks organized to accomplish some business activity. Here each task defines some unit ofwork to be carried out.…”