Nowadays, extended state machines are prominent requirements specification techniques due to their capabilities of modeling complex systems in a compact way. These machines extend the standard state machines with variables and have transitions guarded by enabling predicates and may include variable update statements. Given a system modeled as an extended state machine, with possibly infinite state space and some non-controllable (parameterized) interactions, a pruning procedure is proposed to symbolically derive a maximal sub-machine of the original system that satisfies certain conditions; namely, some safeness and absence of undesirable deadlocks which could be produced during pruning. In addition, the user may specify, as predicates associated with states, some general goal assertions that should be preserved in the obtained sub-machine. Further, one may also specify some specific requirements such as the elimination of certain undesirable deadlocks at states, or fail states that should never be reached. Application examples are given considering deadlock avoidance and loops including infinite loops over non-controllable interactions showing that the procedure may not terminate. In addition, the procedure is applied for finding a controller of a system to be controlled. The approach generalizes existing work in respect to the considered extended machine model and the possibility of user defined control objectives written as assertions at states.

中文翻译：

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扩展状态机的符号细化以及在子组件和控制器的自动推导中的应用

如今，扩展状态机因其能够以紧凑的方式对复杂系统进行建模而成为突出的需求规范技术。这些机器使用变量扩展标准状态机，并通过启用谓词保护转换，并且可能包括变量更新语句。给定一个建模为扩展状态机的系统，可能有无限的状态空间和一些不可控（参数化）的交互，提出了一个剪枝程序，以符号化地推导出满足某些条件的原始系统的最大子机；也就是说，在修剪过程中可能会产生一些安全性和不希望出现的死锁。此外，用户可以指定一些一般的目标断言，作为与状态相关的谓词，这些断言应该保留在所获得的子机中。此外，还可以指定一些特定的要求，例如消除某些不希望的死锁状态，或永远不会达到的失败状态。给出了考虑死锁避免和循环的应用示例，包括在非可控交互上的无限循环，表明该过程可能不会终止。此外，该程序还用于寻找要控制的系统的控制器。该方法概括了关于所考虑的扩展机器模型的现有工作以及用户定义的控制目标的可能性，这些目标写为状态断言。给出了考虑死锁避免和循环的应用示例，包括在非可控交互上的无限循环，表明该过程可能不会终止。此外，该程序还用于寻找要控制的系统的控制器。该方法概括了关于所考虑的扩展机器模型的现有工作以及用户定义的控制目标的可能性，这些目标写为状态断言。给出了考虑死锁避免和循环的应用示例，包括在非可控交互上的无限循环，表明该过程可能不会终止。此外，该程序还用于寻找要控制的系统的控制器。该方法概括了关于所考虑的扩展机器模型的现有工作以及用户定义的控制目标的可能性，这些目标写为状态断言。