Given requirements upon large scale applications and data security

a kind of architecture of EPCISD isco very system is proposed based on the "centralized indexing" mode.This paper first provides a high-level specification for the system's basic functionality and requirements using the TIOA language.Further

this paper proposes a Pub/Sub based

distributed multi-server architecture for the system to make it load balancing

highly available

and scalable in practical applications

and then formally specifies every component in the distributed system respectively.Finally

this paper makes use of a simulation relation to show that the distributed system satisfies/implements the high level specification.