*3.1. Architecture of the PERGAMON System*

Figure 1 presents the architecture of the PERGAMON framework. The Ground Layer has a central place: it stores data from the other components and makes the data available to all connected components via Application programming interfaces (APIs). The connected components are the (i) virtual coach; (ii) serious game(s); (iii) gamification platform; and (iv) the sensor network.

Communication between the different components and the Ground Layer are over secure HTTPS connections and basic authentication is needed to access the RESTful APIs (Representational state transfer (REST) or RESTful web services is a way of providing interoperability between computer systems on the Internet.). The other components in the PERGAMON framework can read, write, update and delete data in the Ground Layer.
