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6.3 The iCore Functional Architecture 251
Some typical examples for viewpoints are Functional, Information, Concurrency,
Development, Deployment and Operational viewpoints.
However, architectural decisions often address concerns that are common
to more than one view. These concerns are often related to non-functional
or quality properties. The approach that the project is following is to define
special perspectives to address these aspects of a concrete architecture,
emphasising the importance of stakeholder requirements. Therefore we are
define a perspective as a collection of activities, tactics, and guidelines that
are used to ensure that a system exhibits a particular set of related quality
properties that require consideration across a number of the system’s
architectural views, where a quality property is defined as an externally
visible, non-functional property of a system such as performance, security, or
scalability.
A complete description of the IoT-A approach can be found in documents
on the IoT-A web site (www.iot-a.eu).
6.3 The iCore Functional Architecture
6.3.1 General Overview
In its most generic sense, the interaction with an iCore system is initiated
through a Service Request generated for the purpose of activating data-streams
from IoT objects and continuously processing these to support an end-user/ICT
application with a set of processes monitoring a situation and producing alerts
when particular conditions are met. Such processes, derived from service templates
are orchestrated and bound to relevant IoT objects using iCore functionality.
This is composed of the three main levels where the bottom one is
called Virtual Object (VO) level and is meant to semantically and reliably represent
real-world objects, the middle layer is called Composite Virtual Object
(CVO) level and expected to provide the means for simple aggregation of VO
functionality, whereas the top level, called Service Level (SL) is expected to
map availability of underlying CVO/VO features to the needs of end-users and
associated IoT applications.
Figure 6.2 shows the iCore architecture at a first level approximation, where
a Service Request is transformed via the Service Level functionality into a
Service Execution Request, which is then passed to the lower CVO/VO levels
for the selection and activation of appropriate objects needed for satisfying