In software-as-a-service paradigms software systems are no longer monolithic pieces of code executing within the boundaries of an organisation, on the contrary, they are conceived as a dynamically changing collection of services, collectively executing, in pursuit of a common business goal. An essential aspect of service selection is determining whether the Quality of Service (QoS) profile of a service satisfies the QoS requirements of a client. In realistic execution environments, such QoS values might be influenced by external, non-controllable events, making it impossible for the service provider to guarantee that the values characterised by a QoS profile will be met, naturally leading to the need of a probabilistic interpretation of QoS profile. In this work we propose: 1) a model for describing probabilistic QoS profiles based on multivariate continuous probability distributions, 2) a language for describing probabilistic QoS requirements, and 3) an automatic procedure for assessing whether a probabilistic QoS profile satisfies a probabilistic QoS requirement.
翻译:在软件服务范式中,软件系统不再是在一个组织边界内执行的单一代码,相反,它们被视为一种动态变化的服务集合,集体实施,追求共同的业务目标;服务选择的一个基本方面是确定服务的质量(QOS)是否满足客户的QOS要求;在现实的执行环境中,这种QOS值可能受到外部、无法控制的事件的影响,使服务供应商无法保证满足QOS特征所标定的价值,自然导致对QOS特征进行概率解释的需要;在这项工作中,我们提议:(1) 一种模型,用以描述基于多变连续概率分布的概率QOS特征;(2) 一种语言,用以描述概率性QOS要求;(3) 一种自动程序,用以评估概率性QOS特征是否满足了概率性QOS要求。