Design Principles for Data-Centric Semantic Interoperability in IoT: The IoTTD Ontology

The increasing heterogeneity of Internet of Things (IoT) devices continues to challenge semantic interoperability across heterogeneous platforms and application domains. Although numerous IoT ontologies and standards have been proposed, many emphasize comprehensive semantic modeling, even in scenarios where only interoperable device data exchange is required, resulting in increased complexity, domain specificity, and limited adoption for generic device data exchange. This paper proposes a data-centric design approach for semantic interoperability based on a set of design principles specifically developed for the semantic representation of IoT device data. Guided by these principles, we introduce IoT Things’ Description (IoTTD), a lightweight OWL ontology that provides a standardized semantic representation for heterogeneous IoT device data. Rather than modeling the complete conceptual space of IoT systems, IoTTD focuses exclusively on the common semantic interface required for interoperable device data exchange. The ontology enables bidirectional semantic data sharing and supports generic SPARQL-based access without requiring prior knowledge of the IoTTD ontology’s structure or content. IoTTD and the proposed design approach are evaluated through structural comparison with representative IoT ontologies, logical consistency verification using HermiT reasoning, semantic annotation examples, and representative application scenarios. The results demonstrate that IoTTD achieves substantially lower structural complexity while preserving the semantic capabilities required for interoperable IoT device data representation. The proposed design principles, together with their implementation in IoTTD, provide the foundation for lightweight semantic interoperability and can serve as a semantic basis for interoperable IoT Knowledge Graphs and Semantic Web applications.