Geoscience Reference
In-Depth Information
analyse this information and present it as if it is presented by a real sensor or mote.
Information acquired from multiple sensors can be represented as the feed of the
virtual sensor. For instance a virtual sensor can be used to present the average heat
of a building by combining values acquired from different sensors. The sensor ser-
vice (i.e. WS-* or REST) will then be used to present the information.
The second layer of the framework deals with the representation of the infor-
mation acquired from the sensor services and its visualisation. The framework
focuses on three types of information consumers, the first set of consumers are
Client Applications including Virtual Globes, Energy Monitoring Applications,
software used in emergency response including GIS, Building Automation soft-
ware, FM Software and so on. The second set of consumers would be the Web
Portals. Currently portals such as Xively (
2013
), ThingSpeak (
2011
), Paraimpu
(
2012
) are becoming popular in representing the information coming from various
sensors around the world. The third set of consumers of the information provided
by, sensor services and digital building models would be personalized smart meter
monitoring systems i.e. as explained in Kamilaris et al. (
2010
) and OpenMUC
(
2012
) is another key software framework in the field.
6 Design and Implementation
The web service that will be elaborated in this section is developed as an imple-
mentation of the Information Acquisition Layer of the Sensor Acquisition
Framework. The aim of the development was acquiring information from the feeds
of virtual sensors, matching every virtual sensor with its container space based on
the geo-location of the virtual sensor and space and then presenting this informa-
tion through a consumer (e.g. a Virtual Globe).
The web service architecture that is developed (Fig.
2
) utilizes the principles
of REST. There are two RESTful interfaces that enable interaction through HTTP
GET and HTTP PUT methods, there are two concrete classes (vSensor-virtual
sensor and Space) that are used to implement the application logic. The applica-
tion logic runs on the data layer that consists of an Oracle Spatial Database and
XML files. The following summarizes the key methods and attributes of the imple-
mentation, based on interface components.
ISensorREST
: This interface contains the definitions of methods for getting the
information about virtual sensors from an XML file (Sensors XML) and generat-
ing required vSensor objects in the Oracle Spatial database, generation of KML
representation of vSensor classes and updating the container of sensors in an event
of location change. The concrete class vSensor deals with the application logic
based on the methods of the
ISensorREST
, contains GUID, spaceID and geometry
(related X, Y, Z) as attributes. The geometric representation of vSensor is a 3D
Point. The spaceID attribute contains the GUID of the Space that the vSensor is
currently located in. The methods in the
ISensorREST
interface are implemented
in vSensor concrete class. Once implemented in the concrete class vSensor,
