Information Technology Reference
In-Depth Information
•
The Core PCG is a middleware server component that publishes interface(web
interface) to the outside world, and contains all logic for managing and searching
gathered sensor data. It is connected with appropriate database in the background
and usually runs on application server.
The PCG demonstration application is a user-located web application, which is
•
used as an example of how to use the PCG and to utilize potentials of the PCG.
It is developed as a web application, with integration of popular geo-maps
(GoogleMaps).
The Client PCG component, which is a part of client WSN desktop component,
•
and is responsible for communication with the Core PCG. There is a special
interface for interaction between WSN applications and Core PCG.
In order to store and manage data from various sensors, the PCG uses a meta-model
suitable for this purpose. Meta-sensor defines all possible data that could be con-
tained in related sensor type, and every value is defined by appropriate meta-
property. As a consequence, each sensor in the system is defined by appropriate
meta-sensor, which defines what properties (value types) could have that sensor, or
what properties (defined by meta-property) could be changed during time. For
example, we can define meta-sensor of type BasicTemperatureSensor, which can
have the following properties (value types): temperature value, unit of that tempera-
ture value (°C, °F, K, …), precision (which could be defined as constant during all
measurements, or could vary from one measurement to another), location (geo-
location of the sensor, which could be constant - sensor is static, or could change
during time - sensor is mobile). The obligatory values for all sensor types are flags
if sensor is active or not (does it work or not), and if sensor is online or not (could
be message routed to it). The list of all meta-sensors and meta-properties (meta-
definitions in PCG terms) could be extended during time.
At the beginning of integration with the PCG, the sensor network should be
registered to the PCG. A sensor network is defined by its URL, name (internal PCG
name), and by its owner. After registration of the sensor network, it could be regis-
tered sensors deployed in that network. For every new sensor its sensor type must
be defined (by meta-sensor described above), as also its unique internal ID inside
the sensor network. Depending on the selected sensor type, various properties will
be added to that sensor, and could be potentially populated at the registration time.
Since sensors are registered, their observations are allowed to be registered (mea-
surements) in time. Registration of the sensor network must be done through the
PCG management application, but registration of sensors could be done either
through management application, or directly through client PCG component
(which is part of some other application dealing with appropriate sensor network).
Registration of sensor observations is possible only through client PCG communi-
cation interface.
For enabling an easy integration with the PCG Core, the client package is pro-
vided with appropriate classes developed in Java. This package contains classes for
connecting to the PCG Core server through socket communication, which is used
for bidirectional communication between the PCG core and client application.
Search WWH ::
Custom Search