Signature required: Making Simulink data flow and interfaces explicit

• Introduce signatures for Simulink, as the true representation of a subsystem's interface.
• Signatures bring traditional software engineering practices into design with Simulink.
• Signatures improve model comprehension, and can be used to automatically document design interfaces.
• Signatures can be used in test harnessing to increase testing coverage and decrease testing effort.
• Signatures can be used to measure quality of Simulink designs and motivate transformations to improve design quality.

Model comprehension and effective use and reuse of complex subsystems are problems currently encountered in the automotive industry. To address these problems we present a technique for extracting, presenting, and making use of signatures for Simulink subsystems. The signature of a subsystem is defined to be a generalization of its interface, including the subsystem's explicit ports, locally defined and inherited data stores, as well as scoped gotos/froms. We argue that the use of signatures has significant benefits for model comprehension and subsystem testing, and show how the incorporation of signatures into existing Simulink models is practical and useful by discussing various usage scenarios. Furthermore, outside of the model setting, signatures have proven to be an asset when exported and included in software documentation.