摘要： 普适计算模式追求随时随地的计算境界，对可用性管理提出了很高的要求。该文基于定量分析的角度，提出了一种基于马尔科夫重生过程(MRGP)的普适计算系统可用性度量方法，以解决关联用户的普适计算系统可用性度量问题。建立了具有双扩展特点的用户模型，分析了用户行为特征；构建了普适计算系统可用性的MRGP模型，对可用性进行了随机过程分析，并给出了对应瞬态和稳态行为的度量方法；结合普适计算模式的特点，定义了普适计算系统请求可用性度量。进行了数值分析，评价了用户和系统参数等因素对普适计算系统可用性度量的影响。

关键词: 可用性度量, 马尔科夫重生过程, 用户模型, 普适计算

Abstract: With the vision of anytime anywhere computation, the availability measurement is playing an important role in pervasive computation. In the perspective of quantitative analysis, this paper presents an MRGP-based approach to address the user associated availability measurement of pervasive computation system. A bidirectional extended user model is developed for describing user behaviors. An MRGP model is established, and a stochastic process-based analysis is conducted. The transient and steady availability are provided for this model, and a novel availability metric, called request availability, is suggested. Numerical analysis is carried out and the results argue that the approach and availability metric can give reasonable evaluation for pervasive computation system.

Key words: Measurement for availability, MRGP, User model, Pervasive computation