Iterative control structures allow the repeated execution of tasks, activities or sub-processes according to the given conditions in a process model. Iterative control structures can significantly increase the risk of triggering temporal exceptions since activities within the scope of these control structures could be repeatedly executed until a predefined condition is met. In this paper, we propose two approaches to unravel iterative control structures from process models. The first approach unravels loops based on zero-one principle. The second approach unravels loops based on branching probabilities assigned at split gateways. The proposed methods can be used to unfold structured loops, nested loops and crossing loops. Since the unfolded model does not contain any iterative control structures, it can be used for further analysis by process designers during the modeling phase. The proposed methods are implemented based on workflow graphs, and therefore they are compatible with modeling languages such as Business Process Modelling Notation (BPMN). In the experiments, the execution behavior of unfolded process models is compared against the original models based on the concept of runs. Experimental results reveal that runs generated from the original models can be correctly executed in the unfolded BPMN models that do not contain any loops.

迭代控制结构允许根据过程模型中的给定条件重复执行任务，活动或子过程。迭代控制结构可能会大大增加触发时间异常的风险，因为可以重复执行这些控制结构范围内的活动，直到满足预定条件为止。在本文中，我们提出了两种从过程模型中解开迭代控制结构的方法。第一种方法解开基于零一原理的循环。第二种方法根据在拆分网关分配的分支概率解开循环。所提出的方法可用于展开结构化循环，嵌套循环和交叉循环。由于展开的模型不包含任何迭代控制结构，在建模阶段，过程设计师可以将其用于进一步分析。所提出的方法是基于工作流图实现的，因此与诸如业务流程建模表示法（BPMN）之类的建模语言兼容。在实验中，基于运行的概念，将展开的流程模型的执行行为与原始模型进行了比较。实验结果表明，从原始模型生成的运行可以在不包含任何循环的展开的BPMN模型中正确执行。根据运行的概念，将展开的流程模型的执行行为与原始模型进行比较。实验结果表明，从原始模型生成的运行可以在不包含任何循环的展开的BPMN模型中正确执行。根据运行的概念，将展开的流程模型的执行行为与原始模型进行比较。实验结果表明，从原始模型生成的运行可以在不包含任何循环的展开的BPMN模型中正确执行。