Interface Data Modeling to Detect and Diagnose Intersystem Faults for Designing and Integrating System of Systems

In system of systems engineering, system integrators are in charge of compatible and reliable interfaces between subsystems. This study explains a systematic solution to identify and diagnose interface faults during designing and integrating systems of systems. Because the systems targeted in this study are real underwater vessels, we first have anatomized 188 interface data transferred between 22 subsystems of them. Based on this, two interface data models are proposed, which include data sets regarding messages and inner fields and transition and decision functions for them. Specifically, a structure model at the message level evaluates how inner fields belong to a message, and a logic model at the field level assesses how each field is interpreted and if the interpreted value is understandable. The software that supports the modeling is implemented using the following concepts: (1) a model-view-viewmodel pattern for overall software design and (2) a computer network for representing sequential properties of field interpretations. The proposed modeling and software facilitate diagnostic decisions by checking the consistency between interface protocols and obtained real data. As a practical use, the proposed work was applied to an underwater shipbuilding project. Within 10 interfaces, 14 fault cases were identified and diagnosed. They were gradually resolved during the system design and integration phases, which formed the basis of successful submarine construction.