Internet of Things – Architecture © - 73 -
3.5 Functional Model
3.5.1 Functional Decomposition
In the IoT-A project, Functional Decomposition (FD) refers to the process by
which the different Functional Components (FC) that make up the IoT ARM are
identified and related to one another.
The main purpose of Functional Decomposition is, on the one hand, to break up
the complexity of a system compliant to the IoT ARM in smaller and more
manageable parts, and to understand and illustrate their relationship on the
other hand.
Additionally, Functional Decomposition produces a superset of functionalities
that can be used to build any IoT system. The output of Functional
Decomposition is described in this document at two levels of abstraction:
The Functional Model (purpose of this section); The Functional View (presented in Section 4.2.2.The definition of the Functional Model is derived by applying the definition of a
Reference Model found in [Brown 2006] to Functional Decomposition: ―The
Functional Model is an abstract framework for understanding the main
Functionality Groups (FG) and their interactions. This framework defines the
common semantics of the main functionalities and will be used for the
development of IoT-A compliant Functional Views.‖
The definition contains the following concepts that need to be explained in more
detail:
Abstract: The Functional Model is not directly tied to a certain
technology, application domain, or implementation. It does not explain
what the different Functional Components are that make up a certain
Functionality Group; Functionality Groups and their interactions: The Functional Model
contains both the Functionality Groups and the interaction between those
parts. A list of the Functionality Groups alone would not be enough to
make up the Functional Model. Both the Functionality Groups and their
interaction are mandatory; Functional View: The Functional View describes the system‘s runtime
Functional Components, including the components‘ responsibilities, their
default functions, their interfaces, and their primary interactions. The
Functional View is derived from the Functional Model on the one hand
and from the Unified Requirements on the other hand. Note that various