The system consists of Client-tier, Middle-tier, Database and
Presentation-tier. Client devices such as cell phones and Palm
Pilot interact with a Flash application through the middle-tier
applications and database system.

Figure 1.Guerrilloffiti System Diagram

1) Client-tier

Any Internet-enabled devices equipped with HTTP or WAP browser
(WML1.1 or HDML2.0+compliant) can be used to send messages to
the board. (For a full list of supported devices and browsers,
see Appendix B. List of supported devices) Since most of the
handheld devices are limited in their resources, the user
interface for these devices are optimized for a simple submit
form and a confirm message.

2) Middle-tier

This tier consists of a Java servlet and other Java
applications running on a Java Application Server.
Message Dispatcher Servlet first detects client device types
and returns appropriate files for the particular device.
When it receives a message from a client, then it
interacts with other applications in order to relay and
store the message.

  Message Relaying Server handles socket connections
  to the presentation-tier and relays messages from
  the servlet to the presentation.

  Database Handler interacts with SQL database system
  to store and retrieve messages upon requests.

  Timer checks the status of system regularly at a
  certain interval. If the system has been idle for
  a certain amount of time, it triggers a mechanism
  to replay the old messages stored in the database
  on the presentation.

  Device Property File holds device and browser information
  such as device type, manufacturer and accepted MIME
  types for each device supported by the system.
  This file is used by the servlet to detect client
  device types.

3) Database

A SQL relational database system stores messages from
users. And optionally, the database can be configured to
hold user information such as device and browser type,
IP address and access time so as to keep track of users

4) Presentation-tier

This is a Macromedia Flash application that runs either
on any traditional web browsers with Flash player
plug-in, or as a standalone application. It connects to
the Message Relaying Server via TCP/IP and draws
messages on a display device in a particular way.

Figure 2.Guerrilloffiti System Architecture

| 01 | 02 | 03 | 04 | 05 | 06 | 07 | 08 | 09 | 10 | 11 | 12 |
Appendix | A1 | A2 | A3 | A4 | A5 | A6 | B0 |