[关键词]
[摘要]
混成系统是实时嵌入式系统的一种重要子类,其行为中广泛存在离散控制逻辑跳转与连续实时行为交织混杂的情况,因此行为复杂,难以掌握与控制.由于此类系统广泛出现在工控、国防、交通等与国计民生密切相关的安全攸关的领域,因此,如何对相关系统进行有效的分析与理解,从而保障系统安全运营,是一项具有重要意义的工作.常规的系统安全性分析手段,如测试、仿真等仅能在一定输入的情况下运行系统来观测系统行为,无法穷尽地检测复杂混成系统在所有可能输入下的行为,因此并不足以保证系统的安全性.区别于测试等方法,形式化方法通过求解系统模型状态取值范围等方法来确认系统模型中一定不会出现相关错误.因此,其对于保障安全攸关混成系统的安全性具有十分重要的意义.形式化方法由形式化规约与形式化验证两个方面构成.因此从以上两个角度分别对形式化规约方向上现有混成系统建模语言、关注性质以及形式化验证方向的混成系统模型检验、定理证明的现有主要技术与方法进行了综述性的回顾与总结.在此基础上,针对现阶段实时嵌入式系统复杂化、网络化的特性,对混成系统形式化验证的重要关注问题与研究方向进行了探索与讨论.
[Key word]
[Abstract]
Hybrid System is a very important subclass of real time embedded system. The behavior of hybrid system is tangled with discrete control mode transformation and continuous real time behavior, therefore very complex and difficult to control. As hybrid system is widely used in safety-critical areas like industry, defense and transportation system, it is very important to analyze and understand the system effectively to guarantee the safe operation of the system. Ordinary techniques like testing and simulation can only observe the behavior of the system under given input. As they cannot exhaust all the possible inputs and scenarios, they are not enough to guarantee the safety of the system. In contrast to testing based techniques, formal method can answer questions like if the system will never violate certain specification by traversing the complete state space of the system. Therefore, it is very important to pursue the direction of formal verification of safety-critical hybrid system. Formal method consists of formal specification and formal verification. This paper reviews the modeling language and specification of hybrid system as well as techniques in model checking and theorem proving. In addition, it discusses the potential future directions in the related area.
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[基金项目]
国家自然科学基金(61100036, 91318301, 61321491);国家高技术研究发展计划(863)(2012AA011205);江苏省自然科学基金(BK2011558)