Orchestrate IoT
services
(publish service
request)
Provides asynchronous way of requesting service
orchestration. IoT services matching the service
request are executed on behalf of the requesting
user once they are available. Complex services
are able to act as user too here, they can issue
requests for IoT services they need to fulfil the
service composition.C.2.2C.2.2 Use Cases
When the individual processes, steps or activities need to be executed, the
Service Organisation diagram gains the focus. Here, the detailed and principal
steps for service composition are shown in a domain agnostic way. The general
principle is always that a mapping of services and Virtual Entities (VEs) must be
found by aligning information from Virtual Entity Resolution and IoT Service
Resolution and that these services are then orchestrated.
As we typically enter the Service Composition and Orchestration components
from the Process Execution component (i.e. services are typically orchestrated
in the execution of a process activity), the Process Execution component is
shown as an actor starting the composition activities. The diagram features the
relationships to other functional components, which we briefly outline below. For
this section we however focus on the main responsibilities of the component:
Increase Quality of Information
Service Composition can increase the Quality of Information by fusing
information from different sources. This relates to the example given in
the previous section. While a single sensor service might not be able to
guarantee a certain level of accuracy for the respective sensor
information, fusing several similar services might increase information
quality considerably, as errors are mitigated and faulty sensors
compensated. Support semantic Service Composition
IoT Services can be composed of other services providing higher level
functionality. The composition is flexible because the composition is not
made of particular services but of services able to provide equal
functionality. If one service fails it can be replaced by a similar one. This
is closely related to the previous aspect and actually further contributes
to an increase of information quality, as dynamic changes in the available
services are taken into account. Orchestrate IoT Services
The Process Execution component delegates service orchestration
(executing the services appropriate to the process activity) to the Service
Composition and Orchestration function. This is the actual interface
between the process execution and the service resolution infrastructure
(the latter being discussed in the following sections). In essence, the