Default α-logic for modeling customizable failure semantics in workflow systems using dynamic reconfiguration constraints

In this paper, we propose a logic based framework to handle failures that occur during the execution of workflows by encoding the failures in formalism of a default normal modal logic. Default logic provides a set of rules for adding premises to logical arguments. Since the specifications of services are encoded in α-logic, defaults can be added to this logic to accommodate the failure semantics for the predicates. We encode predicate failures as predicates and provide a dynamic proof system that handles failures at the execution time. Workflow adaptations are re-synthesized from proofs in our logic using a Curry-Howard style correspondence.