Basic concept of e-mail based information retrieval

At the client side point of view of e-mail based information retrieval model, when the user wants to do something on the Internet or private database in remote location, he may use any front end device (Desktop PC, notebook PC, PDA, or mobile phone) to launch the e-mail client application, and then writing the commands provided by proposed framework or mechanism as the e-mail subject and body, sending this operational e-mail to a specified

e-mail account on the back end server which is registered in advance, and finally, waiting the reply from the back end server. Few minutes later, he may execute the e-mail client application again to check and see his mailbox. In most cases, he will get a response from the back end server, and the contents of the e-mail always are the executed results of his delegated remote application or mobile agent in the remote server.

At the server side point of view of the e-mail based model, the back end server always checks the registered e-mail account to see any incoming messages. When a message has received, it first parses the subject of the e-mail to determine the type of the e-mail and to verify the id and related information according to the information of this e-mail. If the e-mail is with some simple operating commands (such as ‘&&SS;’ to show the status of the server), the server will operate these commands right now, and will pack the results into an e-mail, and then replies the e-mail to the user's e-mail account as soon as possible. In other case, if the user's operation sheets are complex, the server will reply a status report e-mail to the user, and then packs these operations as a program for executing. Meanwhile, the server will send the current progressive statistics to the user every 10 minutes (the default value, it can be changed by the user).

The key mechanism of this model is the role of the e-mail server. It is responsible for accepting the user’s request, and will act as a coordinator to manage the information retrieval application or mobile agents on the server. All of the interactions between the user and the programs on the server should be through the e-mail protocol. Every result e-mail will also be rearranged in a specific manageable format, which can be further operated by user to fetch more information from the Internet by specifying the identification number in the e-mail.

Using e-mail protocol as the gateway between the front end device of information retrieval and other Internet services has many advantages which are shown as follows:

„ Real Cross-Platform: No mater what the devices the user will use, includes desktop PC, notebook PC, PDA, or even mobile phone, most of these devices with networking ability are all equipped the e-mail client application. So, the e-mail based IR mechanism provides the real cross-platform service.

„ User Simplicity: Due to the simplicity of e-mail protocol, there is no any extra works has to be done for the mobile device of the users. All he needs is to look up some information retrieval commands, and

composes those commands into a proper operational e-mail. The other operations are all the same as the normal e-mail application.

„ Compatibility and Flexibility: The e-mail protocol is a very simple but complete protocol. The contents of e-mail can be represented in standard ASCII encoding. Every program can easily read and process the subject and contents of any standard e-mail messages. Thus, the mobile device with limited resources can also easily process the contents of e-mail too. Nevertheless, for the more powerful platform, such as desktop PC or notebook PC, of course they can process more complex data by attaching those data files into the operational e-mail.

„ No client application installation: Because of the e-mail is the common application for many networked devices, most of these mobile devices don’t need to install any related program for adapting this model. This is very convenient for system developer to propose their new services.

All the new services are only to be installed into server. There is no need to modify any application at client side. The cost of deployment will be greatly reduced.

„ No user training: Almost every mobile device users have enough knowledge and abilities to make use of e-mail application to process their own messages. So, this e-mail based model can save lots of extra training works.

„ Low cost, and low and short bandwidth required: Because the e-mail based model doesn't need to educate the user, and it also doesn't need to install any program into client side, the cost and time will be greatly reduced. Moreover, because the e-mail protocol basically is some kind of off-line network protocol, it needs the network connections only while the client application is being transferred the e-mail. Thus, the networking cost will be dramatically reduced too. For a mobile network (such as GSM/WAP/GPRS connection services) with high charged networking service, this is a great deal.

„ User-Oriented and autonomous information retrieval process: Another

user-oriented and autonomous information retrieval process. Under the architecture, all the complex retrieval operations have to be programmed in advance. After the system have received and parsed this e-mail, it will launch a static agent to monitor and schedule the user's mobile agent to do its works, and the static agent also will report the executing status to the user periodically. All the works will be automatically run at the server or across each needed hosts. The user also can write the event handler in their commands sheets of the e-mail to guide the static agent treating every possible occurred event during his works. Finally, after all the works have been done, the static agent will send a complete and well quality result to user's mailbox. That is, if the user's commands sheet is a good design for information retrieval, the boring progress for information retrieval can be discarded. All his works have to be done are just to wait the returned results form his own mobile agent.

„ Server scheduling optimization: Beside, because all of the user's information is handled at the server side, the system can optimize the system's performance according to the system's states. Many technologies such as cache mechanisms, scheduling mechanisms can be applied in the system to boost the system’s performance.