19SafQB

6.2 Defining a Common Architectural Ground 249
More in particular, the main purpose of a Domain Model is to generate a
common understanding of the target domain in question, which is of central
importance to understand architectural solutions and to evaluate them.
Generically, an abstract IoT scenario can be described as generic user that
needs to interact with a physical entity (PE) belonging to the physical world,
within this context, a user can be a living creature or any kind of digital artifact,
such a service or a software agent.
Physical Entities are represented in the digital world via Virtual Entities,
in a one-to-may relationship. The Augmented Entity makes this association
explicit, which is the composition of the two. As it enables every day’s objects
to become part of digital processes, it clearly represents the commonly used
concept of “smart device”.
In the IoT context, a physical entity is linked with a device, which is able
to sense or modify its environment. Resources are software components that
provide information about or enable the actuation on Physical Entities. While
Resources are usually heterogeneous, Services, defined as the mechanism by
which needs and capabilities are brought together, mask the diversity of the
underlying levels offering well-defined and standardised interfaces, for interacting
with Physical Entities and related processes.
The IoT Information Model defines the structure in terms of relations
and attributes of all the information that is handled in a system on a conceptual
level. This includes the modeling of the main concepts for information
flow, storage and their relation. The description of the representation of the
information and concrete implementations are not part of the IoT Information
Model; they can be found in the information view.
The Functional Model contains seven longitudinal functionality groups
complemented by two transversal functionality groups (Management and
Security). These longitudinal groups are: Device, Communication, IoT Service,
Service Organisation, Virtual Entity, IoT Business Process Management,
and Application. The orthogonal groups provide functionalities that
are required by each of the longitudinal groups. The policies governing the
transversal groups will not only be applied to the groups themselves, but do
also pertain to the longitudinal groups.
The Communication Model defines the main communication paradigms
for connecting smart objects. It provides a reference communication stack,
together with insights about the main interactions among the actors in the