Page 28 - U4SSC Data and API requirements for centralized smart city platforms

5) IoT provisioning with the hardware-as-a-service model.
6) People connection via third party virtual meeting places or innovation hub simulators.

7) Material flows via third-party applications that oblige rules (e.g., traffic management).

Figure 11: SCHub multipartner connections enabling several use cases (Anthopoulos et al�, 2022)

4.2 Similarities and differences of SCHub with ETL

The high-level architecture of the SCHub when seen from the data processing perspective is very
similar to an ETL workflow (Extract – Transform – Load). Data are collected from various sources
(extract step) and are processed in order to comply with the northbound data model (Transform).
The last step of the data processing (Load) does not involve a data repository as in the ETL paradigm
but rather an API that serves the data to the users. The differentiation in this last step is what actually
allows the SCHub to operate as a hub without the need for storage of the data retrieved from the
external sources. So instead of an Extract-Transform-Load, SCHub is proposing an Extract-Transform-
Serve (ETS) paradigm.

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