系统建模中基于对象的有向无环图节点粒度的转换

Node Granularity Transformations Based on Object Directed Acyclic Graph in System Modeling

针对化工系统模型难以确定的问题,提出了基于对象的有向无环图节点粒度的转换方法.通过引入嵌套节点实现了基于对象的初始化有向无环图模型,在分析模型组成结构形式的基础上定义了转换过程必须遵守的操作规则,并且详细描述了节点合并和展开的操作流程.同时,从一致性和计算复杂度方面对模型性能进行了评价.最后,使用化工燃油控制系统作为实例,证明了节点转换法能够保证模型形式上的一致性和功能上的完整性,以及操作简便高效的特点,可以比较好地满足系统建模的需要.

To solve the difficulty in modeling a chemical system a new node granularity transformation method based on object directed acyclic graph was proposed. By exploring nested nodes, an initialized object directed acyclic graph model was obtained. Following the analysis to the model structure, the necessary operational rules during the transformation were defined, and the operational procedure of node merging and expansion was elaborated. Simultaneously, this model performance was evaluated from the perspective of consistence and computational complexity. A chemical-engineering fuel control system is taken as a sample and modeled by the proposed method. It is verified that the node granularity transformation enables to guarantee the formal consistence and functional intactness, the operational simplicity and efficiency meet the requirements in the system modeling.