Fig. 5. Flows in experiment 1 for GET requests.Fig. 6. Flows in experiment 1 for POST requests.
Experiment 1: semantic interoperability
The SGAM framework was previously used to demonstrate how a semantic interoperability implementation may be assessed and quantified in the context of DR schemes [49]. The semantic interoperability of the CIM was specifically evaluated to demonstrate how payloads defined in RDF, independent of serialization, and using alternative ontologies (SAREF [51] or SAREF4ENER22) could be successfully and accurately translated into JSON-LD using the DELTA ontology. Nonetheless, such results did not demonstrate how the CIM can also cope with payloads written in formats other than RDF and with models that are not ontologies.
The collection of test scenarios presented in the previous study was expanded in this experiment to evaluate the CIM semantic compatibility in those uncovered circumstances. To that goal, two payloads were specified in XML using the OpenADR XML format. The payloads were then shared using CIMs, which transformed them into their corresponding JSON-LD format. The GET (xml to json-ld), POST (json-ld to xml), and POST (xml to json-ld) messages are depicted in Figs. 5 and 6.
The DELTA ontology SHACL shapes were used to evaluate the payload converted to JSON-LD. 23 A manual validation was also undertaken to guarantee that the translation was done appropriately. Table 2 shows the outcomes of this exploration after delivering 100 payloads in each test case (GET (xml to json-ld), POST (json-ld to xml), and POST (xml to json-ld)).
Table 2 :Results of the semantic interoperability experiments.