安全关键软件的需求递阶层次结构

Requirements of Hierarchy of Safety-Critical Software

软件需求缺陷特别是关于系统安全性方面的需求缺陷已逐渐成为导致飞机等安全关键系统发生事故的主要根源。在基于模型的软件开发中,有效管理开发出来的软件需求将有助于解决这一问题。为避免软件需求的无序性导致软件需求缺陷特别是安全性需求缺陷的生成,在借鉴层次分析法的有关思想基础上,提出了层次化管理安全关键软件需求的思路,构建了安全关键软件的需求递阶层次结构。该结构按照目的、准则、方案三层将软件需求有序组织在一起,不仅明确表达了不同层次软件需求之间的关系,有助于保证软件需求的一致性、可溯性,而且说明了软件安全性需求与危险场景之间的关系,有助于预防安全性需求缺陷,从而可以有效规避软件安全性问题。

The defects in requirement for safety critical software is commonly seen as a major cause of safety critical system failure. In model-based software development, the problem can be solved by effectively managing software requirements and especially safety requirements. To avoid software bugs generated from disordered requirement, a management method of software requirement is presented based on Analytic Hierarchy Process （AHP） and a requirement hierarchy is constructed with goal layer, criteria layer and solution layer. The hierarchy describes unambiguously the relationships among different layers of requirement, which is useful for software requirement＇s consistency and traceability. The hierarchy also describes the relationships between software safety requirements and hazard scenarios, which can prevent the defects from being generated and then can improve the software safety.