Hyper Temporal Networks
This work addresses the limitation of temporal constraint models in process-aware information systems by providing a more expressive yet efficient framework for workflow synchronization.
The authors introduced Hyper Temporal Networks (HyTNs) as a generalization of Simple Temporal Networks (STNs) to handle disjunctions of maximum delay constraints, enabling representation of natural constraints like synchronization events that STNs cannot express, while maintaining practical pseudo-polynomial time algorithms for consistency checking and scheduling.
Simple Temporal Networks (STNs) provide a powerful and general tool for representing conjunctions of maximum delay constraints over ordered pairs of temporal variables. In this paper we introduce Hyper Temporal Networks (HyTNs), a strict generalization of STNs, to overcome the limitation of considering only conjunctions of constraints but maintaining a practical efficiency in the consistency check of the instances. In a Hyper Temporal Network a single temporal hyperarc constraint may be defined as a set of two or more maximum delay constraints which is satisfied when at least one of these delay constraints is satisfied. HyTNs are meant as a light generalization of STNs offering an interesting compromise. On one side, there exist practical pseudo-polynomial time algorithms for checking consistency and computing feasible schedules for HyTNs. On the other side, HyTNs offer a more powerful model accommodating natural constraints that cannot be expressed by STNs like Trigger off exactly delta min before (after) the occurrence of the first (last) event in a set., which are used to represent synchronization events in some process aware information systems/workflow models proposed in the literature.