Table 2 demonstrates that the CIM can successfully translate payloads from non-RDF formats into JSON- LD payloads modeled by the DELTA ontology. Although the XML format and the OpenADR schema were tested, additional interoperability modules can be installed to allow the CIM to convert payloads from other DR standards with alternative formats and models.

Experiment 2: scaling parallel requests

All requests represented in Figs. 5 and 6 are routed through the CIMs in this experiment. The time (in seconds) necessary to acquire the findings after transmitting these payloads, including the translation time involved in the data exchange, is the performance statistic for this experiment. These findings are detailed in Table 3 and illustrated in Fig. 7. From 1 to 600, the number of concurrent requests increases by 50 thread ticks. In order to compare the results, the averaged reaction times were converted to a logarithmic scale.

Finally, the CIM limits the number of parallel requests to 650 for security concerns; as a result, the maximum number of parallel requests for this experiment was set at 600.

Based on the statistics in Table 3, it appears that certain queries have extremely comparable response times. The Iman- Davenport test [52] was used to determine whether there are significant statistical differences between all of these requests, both GET and POST, with and without translation, at a confidence level of 95%, in order to determine whether the translations cause overhead during data transmission.

As a consequence, the test finds no statistically significant differences between GET (json-ld), GET (xml to json-ld), POST (json-ld), and POST (json-ld to xml), however there are differences with POST (xml to json- ld). This difference is plainly seen in Fig. 7, where the time required to respond to these queries is substantially longer than the others.

Conclusion: This experiment demonstrated that sharing data across DR systems utilizing CIMs is a quick process with a linear trend, either when parallel requests are received, as seen in Fig. 7. It is worth noting that when there is no translation, 600 parallel requests are responded in less than half a second (<500 ms).