I. Introduction
Services computing system is defined as a complex system, which involves the interaction, composition, and collaboration among IT services, as well as the interaction and dependencies between users and service providers (Sps) [1], [2]. Chen et al. [3] described service computing system as a group of interacting IT services that do not only focus on the technology of service computing and IT infrastructures but also pay attention to the performance of the IT services. Moreover, Ye et al. [4] described service computing system as a complex system that consists of various services that can be consumed by users by integrating individual services into composite services to meet the complex requirements of users. It can be summarized that service computing system is a service system enabled by service computing technology.