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2. Architecture of the Visualization WWW server

2. 3. Loading user data

There are two ways to easily access user data without imposing extra programming effort on the user. Both methods were explored in earlier application. Both methods allow data access without effecting the usual security barriers of computer systems on the net.

Fig. 2: Using the Cut&Paste or Clipboard function to enter data into the front-end

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For a limited size of user data we implemented the Cut/Paste method. The JAVA driven user interface supplies a text window to input user data. It is obvious that the user would not use such a window to type in data by hand. In general, the user will own an application which will be data producer. This may either be a simulation program, a data base program or a simple texteditor. These programs frequently produce output to be seen on the screen. Provided this output has one of the acceptable formats, this stream of text may simply be handed to the JAVA front-end of the visualization server using the Cut/Paste function or the Clipboard function of the window system (Figure 2). This is an extremely simple way of entering the data. This method is well known to any WWW user. There are no considerations of access protection which would unnecessarily complicate the use of the visualization server.

A second method of loading user data is by using the WWW-URL address scheme. This method was also explored in the Vectorize Tool [13]. The method requires a little more effort on the user's side. In order for the method to work, the user needs to be able to make his data accessible on a Web-site.

Fig. 3: User interface of the DLR WWW Flow Visualization Server. The user data is transmitted to the server by Cut&Paste into the white text field. Additional control elements such as menus and parameter input allow to control the visualization method.

The data needs to be supplied in a text-file in one of the specified formats on any Web site. The data may be read protected to the general public but must be accessible for the host running the visualization server.

The visualization server's user interface will query the location of the data as a standard URL address. This address will be use to load the data to the visualization server.