Evaluation of IT systems considering characteristics as system of systems

It is important for IT system integration (SI) to evaluate non-functional requirements (NFR) in design phase. However, since IT systems show system of systems (SoS) characteristics, the evaluation is a difficult work. An IT system consisting of independently developed systems has to be evaluated comprehensively as a whole system. Moreover, the details of some systems are often unknown, i.e., black box. Model-based systems engineering is a promising approach for the evaluation in design phase. This paper describes our in-house tool named CASSI (Computer Aided System model-based System Integration environment). CASSI consists of a repository of “system models” as elements to model an SoS, and tools to evaluate NFR of the SoS. CASSI includes two aspects; modeling as detailed as possible for precise evaluation and including black box as necessary. This paper represents the results and effectiveness of applying CASSI to SI.