Understanding Discord NSFW Servers A Guide for Responsible Users.pdf
Semantic Sensor Service Networks
1. Semantic Sensor Service Networks
Wei Wang, Payam Barnaghi, Gilbert Cassar, Frieder Ganz, Pirabakaran
Navaratnam
Centre for Communication Systems Research
University of Surrey
Guildford, Surrey
United Kingdom
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2. Sensors, Sensor Networks and Internet of
“Things”
Physical world objects
e.g. A room, a car, A person;
Feature of Interest
e.g. Temperature of the room, Location of the car,
heart-rate of the person;
Sensors
e.g. Temperature sensor, GPS, pulse sensor
Embedded devices
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3. Semantics and Sensor Networks
Image credits:
[1] Protocols and Architectures for Wireless Sensor Networks, Holger Karl, Andreas Willig, Wiley, 2005 3
[2] Cisco - Interne of Things
5. The Internet of Things
A primary goal of interconnecting devices and
collecting/processing data from them is to create
situation awareness and enable applications,
machines, and human users to better understand their
surrounding environments.
The understanding of a situation, or context,
potentially enables services and applications to make
intelligent decisions and to respond to the dynamics of
their environments.
A key enabler is providing Services that represent
sensors/resources and integrating them into the
cyber-space.
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6. Semantics, sensors and services
Semantics are machine-interpretable metadata (for mark-up),
logical inference mechanisms, query mechanism, linked data
solutions
For semantic sensor services this means:
ontologies for: devices (e.g. sensors), observation and
measurement data (e.g. sensor readings), domain concepts (e.g.
unit of measurement, location), service descriptions (e.g. IoT
services) and other data sources (e.g. those available on linked
open data)
Semantic annotation should also supports data represented
using existing forms
Reasoning /processing to infer relationships or hierarchies
between different resources, data
Semantics (/ontologies) as meta-data (to describe the
services/resources) / knowledge bases (domain knowledge).
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8. Existing models for resources and data
W3C Semantic Sensor Network Incubator
Group’s S N ontology (mainly for sensors and
S
sensor networks, observation and
measurement, and platforms and systems)
Quantity Kinds and Units
Used together with the SSN ontology
based on QUDV model OMG SysML(TM)
Working group of the SysML 1.2 Revision Task
Force (RTF) and W3C Semantic Sensor Network
Incubator Group
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10. Existing models for services
OWL-S and WSMO are heavy weight models: practical
use?
Minimal service model
Deprecated
Procedure-Oriented Service Model (POSM) and Resource-
Oriented Service Model (ROSM): two different models for
different service technologies
Defines Operations and Messages
No profile, no grounding
SAWSDL: mixture of XML, XML schema, RDF and OWL
hRESTS and SA-REST: mixture of HTML and reference
to a semantic model; sensor services are not anticipated
to have HTML
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11. Semantic modelling
Lightweight: experiences show that a lightweight
ontology model that well balances expressiveness and
inference complexity is more likely to be widely adopted
and reused; also large number of IoT resources and
huge amount of data need efficient processing
Compatibility: an ontology needs to be consistent with
those well designed, existing ontologies to ensure
compatibility wherever possible.
Modularity: modular approach to facilitate ontology
evolution, extension and integration with external
ontologies.
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12. IoT.est service profile highlight
ServiceType class represents the service technologies:
RESTful and SOAP/WSDL services.
serviceQos and serviceQoI are defined as subproperty of
serviceParameter; they link to concepts in the QoS/QoI
ontology.
serviceArea: the area where the service is provided;
different from the sensor observation area
Links to the IoT resources through “exposedB property
y”
Future extension:
serviceNetwork, servicePlatform and serviceDeployment
Service lifecycle, SLA…
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15. Linked data principles
using URI’s as names for things: Everything is
addressed using unique URI’s.
using HTTP URI’s to enable people to look up
those names: All the URI’s are accessible via
HTTP interfaces.
provide useful RDF information related to
URI’s that are looked up by machine or
people;
including RDF statements that link to other
URI’s to enable discovery of other related
concepts of the Web of Data: The URI’s are
linked to other URI’s.
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16. Linked data layer for not only IoT…
Diagram from Stefan Decker, http://fi-ghent.fi-week.eu/files/2010/10/Linked-Data-scheme1.png; linked data diagram: http://richard.cyganiak.de/2007/10/lod/
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19. Conclusions
Sensor service connectivity, discovery and
composition are some of the most key issues
in semantic sensor service networks.
SOA based design can support seamless
integration to existing applications on cyber-
space.
While the direct access method uses the
standard HTTP protocols for service
communications, the intermediate access
method is designed on the top of the
Constrained Application Protocol (CoAp) and
6LowPan for devices operating in constrained
environments. 19
Limitation: OWL-S and hREST complement each other; all of them do have connections to resources, platforms… do not consider the unique nature of IoT services