Internet of Things Architecture

Internet of Things – Architecture © - 58 -

Class A

Class B Class C

Figure 7 : UML Aggregation and Composition.

Finally, an "open arrow" is used to denote a "one-way" association. The
notation shown in Figure 8 indicates that every object in class A is associated
with zero or more objects in class B (), and that every object in class B is
associated with exactly one object in class A. However more importantly, this
notation indicates that a class A object will "know" class B objects with
which it is associated, and that a class B object will "not know" the class A
object with which it is associated, ref. Sensor and Physical Entity in Figure 10.

Class A Class B

1 *

Figure 8 : UML Association.

The cardinalities (―asterisk‖, ―1‖ etc) are to be read as follows: from the source
read the relation and the cardinality on the target gives the multiplicity with
which the source can be in that relation with the target. For the inverse relation,
the cardinality at the source is relevant. For example (see Figure 10 ), a Tag
identifies no or one (0..1) Physical Entity – whereas a Physical Entity may be
identified by 0 or more Tags. A Virtual Entity may contain 0 or more other Virtual
Entities, whereas a Virtual Entity can optionally be contained in at most one
other Virtual Entity. Concepts depicting hardware are shown in blue, software in
green, animate beings in yellow, and concepts that fit into either multiple or no
categories in brown.

3.3.2.2 The concepts of the IoT Domain Model

The most generic IoT scenario can be identified as that of a generic User
needing to interact with a (possibly remote) Physical Entity (PE) in the physical
world (see Figure 9 ). In this short description we have already introduced the