I. Introduction
Today, the rapid advancement of intelligent technologies, such as the Internet, Internet of Things, big data, cloud computing, virtual reality, blockchain, and artificial intelligence, is driving the accelerated evolution of human society. This has led to the emergence of a new social infrastructure known as "smart services", which can be described by the equation "data + computing power + AI algorithm = smart services". As a result, the entire society is gradually transforming into a service ecosystem, where a unified "services" logic is applied to everything, including applications, platforms, data, algorithms, and resources, known as "Everything as a Service" (XaaS) [1], [2].