Database Reference
In-Depth Information
accordingly discovering the sensors that can contribute to its ful
llment. It also
selects the resources, i.e., sensors that will support the service deployment, while
also performing the relevant reservations of resources.
The Service Delivery & Utility Manager (SD&UM), which performs a dual role.
On the one hand, it combines the data streams as indicated by service workflows
within the OpenIoT system, in order to deliver the requested service. To this end,
this component makes use of the service description and the resources identi
￿
ed and
reserved by the (Global) Scheduler component. On the other hand, this component
acts as a service metering facility, which keeps track of utility metrics for each
individual service.
The Pub-Sub server (QoS Manager), which is the component which monitors
over time the global demand for sensor data generated by MIOs and manages the
data acquisition process from MIOs to achieve a desired sensing coverage while
optimising parameters such as energy and bandwidth consumption, sensor trust-
worthiness and/or data propagation latency.
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The Security module (CAS server), which is based on Jasig CAS ( http://www.
jasig.org/cas ) and provides OAuth2.0 authentication and authorization for all other
OpenIoT modules.
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The Request De
cation of service requests to
the OpenIoT platform. It comprises a set of services for specifying and formulating
such requests, while also submitting them to the Global Scheduler. This tool fea-
tures a GUI (Graphical User Interface), which resides at the heart of the visual IoT
development paradigm that is introduced in the following sections.
nition tool, which enables the speci
The Request Presentation component, which is in charge of the visualization of
the outputs of an IoT service. This component selects mashups from an appropriate
library in order to facilitate service presentation. Service integrators and solution
providers have the option to enhance or override the functionality of this component
towards providing a presentation layer pertaining to their solution.
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The Con
guration and Monitoring component, which enables management and
￿
con
guration functionalities over the sensors and the IoT services that are deployed
within the platform. It is also supported by a GUI.
The delivery of IoT services according to the OpenIoT architecture relies on the
following information flows and interactions between the various elements:
X-GSN nodes are
the available virtual sensors to the Directory
Service and start to publish their data in SSN compliant RDF format based on each
X-GSN local con
announcing
￿
guration.
Users request from the Scheduler all the available sensor/ICOs types that satisfy
speci
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nition UI. The
request is sent to the Scheduler service, which queries the Directory Service for the
ICOs that ful
c attributes (e.g., coordinates, radius) by using the Request De
ll the criteria set in the request.
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The Scheduler executes a combination of queries (SPARQL-based) according to the
previously user speci
ed request.
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The Directory Service retrieves the data and replies back to the Scheduler with the
available sensor types.
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