Updatable timed automata (UTA) are extensions of classic timed automata that allow special updates to clock variables, like x:= x - 1, x := y + 2, etc., on transitions. Reachability for UTA is undecidable in general. Various subclasses with decidable reachability have been studied. A generic approach to UTA reachability consists of two phases: first, a static analysis of the automaton is performed to compute a set of clock constraints at each state; in the second phase, reachable sets of configurations, called zones, are enumerated. In this work, we improve the algorithm for the static analysis. Compared to the existing algorithm, our method computes smaller sets of constraints and guarantees termination for more UTA, making reachability faster and more effective. As the main application, we get an alternate proof of decidability and a more efficient algorithm for timed automata with bounded subtraction, a class of UTA widely used for modelling scheduling problems. We have implemented our procedure in the tool TChecker and conducted experiments that validate the benefits of our approach.

中文翻译：

---

可更新定时自动机的可达性变得更快、更有效

可更新定时自动机 (UTA) 是经典定时自动机的扩展，允许在转换时对时钟变量进行特殊更新，例如 x:= x - 1、x := y + 2 等。UTA 的可达性通常是不可判定的。已经研究了具有可判定可达性的各种子类。UTA 可达性的通用方法包括两个阶段：首先，执行自动机的静态分析以计算每个状态下的一组时钟约束；在第二阶段，枚举可到达的配置集，称为区域。在这项工作中，我们改进了静态分析的算法。与现有算法相比，我们的方法计算了更小的约束集并保证了更多 UTA 的终止，从而使可达性更快、更有效。作为主要应用，我们得到了可判定性的替代证明和更有效的定时自动机算法，有界减法是一类广泛用于建模调度问题的 UTA。我们已经在工具 TChecker 中实施了我们的程序，并进行了验证我们方法的好处的实验。