Universität Bremen TZI The Semantic Definition Format (SDF) is a format for domain experts to use in the creation and maintenance of data and interaction models that describe Things, i.e., physical objects that are available for interaction over a network. It was created as a common language for use in the development of the One Data Model liaison organization (OneDM) definitions. Tools convert this format to database formats and other serializations as needed. The SDF format is mainly intended for interchange between machine generation and machine processing. However, there is often a need for humans to look at and edit SDF models. Similar to the way Relax-NG as defined in ISO/IEC 19757-2 has an XML- based format and a compact format (its Annex C), this specification defines a compact format to go along SDF's JSON-based format. // The present version of this document is mostly a proof of concept; // it received positive initial feedback on the approach taken and is // awaiting completion of the initial implementation.