Ultra large scale systems are a new generation of distributed software system that are composed of various changing, inconsistent or even conflicting components that are distributed in a wide domain. Some important characteristics of these systems include their very large size, global geographical distribution, operational and managerial independence of their member systems. The main function of these systems arises from the interoperability between their components. Nowadays one of the most important challenges facing ultra large scale systems is the interoperability of their component systems. Interoperability is the ability by which system elements can exchange and understand the information required with each other. This paper aims to solve the mentioned challenge, which is divided into two main parts. In the first part, this paper presents a maturity model for the interoperability of ultra large scale systems, by using the interoperability level of the component system of one ultra large scale system its maturity level can be determined. In the second part, by proposing a framework we try to increase the interoperability of the component systems in ultra large scale systems based on the interoperability maturity levels determined in the first part. Consequently their interoperability is improved. 
An interoperability model for ultra large scale systems