The concept of structured occurrence nets is an extension of that of occurrence nets which are directed acyclic graphs that represent causality and concurrency information concerning a single execution of a distributed system. The formalism of structured occurrence nets has been introduced to facilitate the portrayal and analysis of the behaviours, and in particular failures, of complex evolving systems. Such systems are composed of a large number of sub-systems which may proceed concurrently and interact with each other and with the external environment while their behaviour is subject to modification by other systems. The purpose of this paper is to provide an extension of structured occurrence nets to include models built up of acyclic nets rather than occurrence nets.

翻译：结构化发生网的概念是对发生网的扩展。发生网是一种有向无环图，用于表示分布式系统单次执行过程中的因果性与并发性信息。结构化发生网的形式化方法旨在促进复杂演化系统行为（尤其是故障行为）的刻画与分析。此类系统由大量子系统组成，这些子系统可能并发运行、彼此交互并与外部环境交互，同时其行为可能受到其他系统的修改。本文旨在将结构化发生网扩展为基于无环网而非发生网构建的模型。