In the top of architecture, we added a module in a way that the
drivers can interact with the SafeTrack Mobile. With this User
Interface, they can see in a map, the current location, the traveled
road with visited points, the next stop, and also the remaining
stops and final destination. Moreover, the User Interface provides
to the drivers specific information of each set, such as, local and
date that every load has to be picked up and delivered.
The communication component is composed by two modules:
Service Consumer and Duino Interface. The Service Consumer is
responsible for the communication with the SafeTrack Server,
which is done by GPRS using SOAP protocol. This module packs
the information into SOAP messages and sends them through
HTTPS to the SafeTrack Server. In case of reply, the module receives
the SOAP messages and transforms them into data structures at a
higher level. The module Duino Interface does the communication
between the component SafeDuino and the mobile device, using
Bluetooth.
The Logical Module is in charge of processing the data, and also
interconnects to other components of SafeTrack Mobile. It is divided
into four submodules. The Access Manager does the user’s authentication
with the SafeTrack Server, allowing access control and context
management. The Event Manager deals with the received RFID
events through the Duino Interface. The manager transforms the
raw data of events into structured objects and sends them to the
Data Access module to be persisted in a temporary storage buffer,
called Event Buffer.
The Fusion Manager calculates the latitude, longitude and the
current velocity of Carrier Station using the GPS signal. It also associates
the stored RFID events in the Event Buffer to the location’s
information and velocity of Carrier Station, sending it to the
SafeTrack Server via Service Consumer. The data is sent in a priority
way, so if the Offline Buffer has associated data, it will be sent,
otherwise new information of location and velocity are calculated
and sent to the SafeTrack Server by the Service Consumer. In case of
error in sending it, the information return to the Offline Buffer until
the reestablishment of the connection. After sending, the module
Fusion Manager waits the return of SafeTrack Server, informing
the alert code to be generated by the SafeTrack Mobile, if there is
any problem with the Carrier Station. In addition, the Alerts
Manager module is called to do the necessary measures, making
the authentication with the SafeTrack Server. In this process, a cryptography
of the IMEI (International Mobile Equipment Identity)
number of the device with a SHA-1 algorithm is sent with other
associated information.
The Alerts Manager also has a service to continuously check
error’s occurrences, caused by misuse of the device or driver carelessness.
In these cases, besides SMS text messages and audible
warnings, the system informs the SafeTrack Server that those problems
happened. The supported alarms are: shutting down the
mobile device, low battery of the mobile device, shutting down
the GPS, and closing the SafeTrack Mobile application.
The Data Access Module manages the Offline and Event Buffer.
The Offline Buffer is a local database that is used only when a connection
with the server is lost. The objective of the Offline Buffer is
to keep all acquired positions stored until the connection is
restored. The reason to implement this feature is that sometimes
the device can be passing through a shadow zone (an area without
GPRS coverage that hinders the device to send data to the server).