5.6.4.6 Specification of IoT Domain Model
Based on the Business Process Model presented before, a domain model can
be derived that identifies the Physical and Virtual Entities, the IoT Services, the
Devices, Resources, and the users that are involved in the use-case. The
Human User is the doctor or other medical staff who is responsible to monitor
the towels in the operation theatre. The actual monitoring of the towels by
comparing the used towels with the ones currently in use is done by software
implementing the ̳Monitor towel process‘ as depicted in Figure 110. The User
checks only that no towels are still in use when the operation is about to end.
The software ̳Operation Theatre Application‘ is modelled as Active Digital
Artefact. Each towel is a Physical Entity that has one RFID tag attached so that
the number of towels corresponds to the number of tags. Each physical towel
has a digital counterpart modelled as Virtual Entity. There are three RFID
readers deployed in the scenario at different significant locations of the
operation theatre (Instrument Table, Operation Table, and Waste Bin) that are
modelled as Sensor Devices. Each of the Sensors hosts an OnDevice
Resource that is exposed by an ̳Object Inventory Service‘ as depicted in Figure
109. These services store events by invoking the ̳Event Storage Service‘ that
exposes the Network Resource ̳Event History‘. This Resource is also exposed
to the ̳Operation Theatre Application‘ by the Event History.