Microsoft, mainly due to the availability of version 2.0 on every WM6.0 device without the need for further installations/updates on the device. Also, the .NET Framework is a cluster of closely related new technologies that revolutionize everything from database access to mobile applications. It includes large programming libraries, solutions for common problems, and a virtual machine that manages the programs execution written specifically for the framework. There are several programming languages that are supported by the .NET Framework. Those include Visual Basic, C#, JScript .NET (a server-side version of JavaScript), J#, and C++. We have used C# for developing the mTracker application. The software chosen for the development of this application was the Microsoft Visual Studio 2008 PRO IDE (Integrated Development Environment). It offers the Microsoft Windows Mobile SDK V5.0, which we upgraded to the V6.0. Both versions offer emulation debug for easy initial debugging of mobile applications.
IV. EVALUATION AND VALIDATION OF MTRACKER
A. User experience and mTracker interface This subsection introduces a general idea of both mobile application (mTracker) and PC application (mTrackerMap), as well as, their use in practical deployment. To ease the user interaction with the mTracker, the interface is made as simple as possible. The main window of the application is very intuitive. The interface displays information related to the GPS and current GSM Cell ID. The Menu softkey provides extended functionalities such as turn the GPS receptor on or off, information related to the actual Cell ID or access the application settings through a login window. If the password is incorrect the user is not allowed to the settings window, therefore, he cannot change the predefined settings of the application, like the tracking tool or the SIM card detection tool. If both tools are enabled, then they will start to execute automatically when the device operating system restarts. After a successful login, with the authentic password, the settings window will appear. This window has four TABs, which are displayed at the bottom of the window. The options included in the TABs allow the administrator to customize the application. Through the TAB SMS, the user can set the emergency contact that will receive the alerts, the keypad key that shall be pressed to send the distress call and the text included in the SMS. The contacts displayed in this TAB are the contacts of the PDA Microsoft Pocket Outlook. The administrator has the ability to add, remove or edit a contact. When mTracker starts to execute and if the option tracker is on, the system starts automatically the tracking of the device, through the GPS and GSM Cell ID. It will compare the received GPS coordinates to the predefined interest point and check if the device is within the security radius. If the system is detected out of the radius a warning via SMS will
be sent with the current GSM cell and the present or the latest GPS coordinates. Note that the GSM cell position is not as accurate as the GPS coordinates, therefore to calculate the position only the GPS coordinates are used. As indicated in Figure 3a, the tracker settings include a start date and an end date, the time of the day that the device shall be tracked, the interval to get the GPS coordinates and GSM cell and finally the security radius around the interest point. The administrator can set the interest point through the TAB GPS, as Figure 3b depicts. The application will use the ICC ID to identify the SIM card in the device. The third TAB, classified as ID, allows the administrator to enable or disable the SIM card detection and see the current ICC ID of the SIM card in use. It also provides the present password and the ability to change it. If the administrator chooses to enable the SIM card detection, the application will compare the ICC ID stored in memory with the ICC ID detected when the PDA operating system restarts.
Figure 3. (a) TAB Tracker (b) TAB GPS.
Thus, if the ICC ID is different, a warning via SMS will be sent to the emergency contact with the current GSM cell, the present or the latest GPS coordinates and the phone number of the unauthorized SIM card. After concluding the application customization, the Save Button can be pressed to record the data in a file. The application has the ability to test the values introduced by the administrator, such as the interest point coordinates or the dates to activate the tracker. Unless no errors are detected, the data will be stored in the PDA memory, otherwise, a warning message displays if there are any errors. The mTrackerMap is a PC application that allows the user access to the data stored in the PDA. Furthermore, it provides instant access to GoogleMaps. When the PDA is connected to the PC, via USB, the mTrackerMap will access the data stored through the buttons Load Cell IDs and Load GPS coordinates. Those are placed at the bottom left of the main window, as shown in Figure 5. Each button will load the corresponding file in the PDA to a list placed over them. As a result, the list will be filled with GSM cells or GPS coordinates sorted by date in ascending order. To filter the