Norm-Aware Planning: Semantics and Implementation

Norms are a way to specify acceptable behaviour in a context. In literature there is a lot of work on norm theories, models and specifications on how agents might take norms into account when reasoning but few practical implementations. In this paper we present a framework and an implementation for norm-oriented planning. Unlike most frameworks, our approach takes into consideration the operationalisation of norms during the plan generation phase. In our framework norms can be obligations or prohibitions which can be violated, and are accompanied by repair norms in case they are breached. Norm operational semantics is expressed as an extension/on top of STRIPS semantics, acting as a form of temporal restrictions over the trajectories (plans) computed by the planner. In combination with the agent's utility functions over the actions, the norm-aware planner computes the most profitable trajectory concluding to a state of the world where no pending obligations exist and any (obligation/prohibition) violation has been handled. An implementation of the framework in PDDL is provided.