一句话:提出 EPIK,用可直接观测的系统级属性引导贝叶斯先验,从而更准确地对模型转移参数学习并验证难以测量的定量性质。
将贝叶斯学习与定量验证结合可分析软件系统的可靠性和响应时间等关键定量性质,但验证结果的准确性与鲁棒性依赖贝叶斯推断中的先验知识(PK);不准确或无信息量的 PK 会导致错误结果。已有方法要求为形式模型转移参数提供 PK。EPIK 转而利用可直接观测、与真实语义相关的系统级属性,将先验知识获取与嵌入问题形式化为一个 twofold 优化问题,用以推导未知转移参数的分布,并将这些分布嵌入定量验证,以验证新的或难以测量的 elusive 性质。基于多个真实案例变体和不同 EPIK 实例的实验评估表明该方法有效、灵活且具有通用性。
Combining Bayesian learning and quantitative verification is a powerful toolset for analysing key quantitative properties of software systems, like reliability and response time. However, the accuracy and robustness of verification results strongly depend on the prior knowledge (PK) underlying Bayesian inference. This knowledge reflects original beliefs about the probability of events and typically depends on domain expertise. Using inaccurate or uninformative PK can negatively affect quantitative analysis, yielding incorrect verification results. Our EPIK approach tackles this important challenge by eliciting and embedding PK in quantitative verification equipped with Bayesian estimators. Unlike existing approaches that require PK on formal model transition parameters, EPIK leverages system-level properties that are directly observable and are linked to real-world semantics. EPIK formulates a twofold optimisation problem to derive the distributions of unknown transition parameters and then embeds these distributions to verify new or difficult-to-measure (elusive) properties. The detailed experimental evaluation using multiple variants of real-world case studies and diverse EPIK instantiations shows its effectiveness, flexibility and generality.