Event-Based System for Generation of Traffic Services in Road Congestions - Foundations on Natural and Artificial Computation - page 205

provides thematic maps that include information regarding road occupation and
can show alternative routes when destination has been settled.
On the other hand, the WFS service recovers geo-spatial data by means of
independent calls to the platform. In the trac center, it is used as a WMS
complement, since makes it possible to check feature values, instead of show
them graphically. For instance, with WMS can plot a map with the roads colored
depending on their occupation, and WFS can report the number of vehicles per
kilometer and the average speed or the length of a trac jam in km.

5 System Architecture / Event-Based System

The system implementation follows the scheme shown in Fig. 3. On it, it can be
observed that data coming from vehicle events or infrastructure are processed in
the trac center. Base stations are deployed along the road and work as interme-
diary between vehicles and trac center in order to ease off the communications.
They receive information coming from the vehicles in their corresponding envi-
ronments and work as intermediary between vehicles and the trac center. To
do this, wireless-capable laptops were employed. Trac center is in charge of
most of the processing as it is detailed later.

Fig. 3. Scheme of the system architecture

A prototype vehicle containing all necessary sensors and communication links
was employed for the tests. For navigation purposes GPS, INS sensors and GIS
maps are mounted board the vehicle. The use of inertial sensors, accelerometers
and gyroscopes, supplies continuous positioning even in cases without GPS cov-
erage, and fast dynamic measurements [7]. To integrate the data coming from