Variable Length Documents

This demo presents an experimental system for on-line text presentation -- whereby the user specifies how long they want the document to be, and a text of that size is provided. The user might choose to see the hundred-word version, or the thousand-word version, or somewhere between.

Figure 1 shows the web browser (Netscape) interface to the system, also showing (part of) the text before it is reduced. Figure 2 shows the same document, although with a 200 word limit set. The text is mostly coherent, with however some minor problems. One can see these as the cost of this sort of summarisation.

: The VLTP interface

: Scottish History text at 200 words

This technique, what we call variable-length text presentation, involves two steps:

1. Document Preparation: the document is marked-up according to its rhetorical structure. For this we use an RST Analysis Tool, which allows a user to graphically link segments of text into an RST-tree. (This tool might be shown in the demo, or screen dumps).

2. Document Presentation: a web-connected program is then used to present such documents. In response to a user's request, the program `prunes' off less essential branches of the RST-tree until a text of the required size is produced.

Because of the time-cost of document markup, this technique is most useful for documents with a longer shelf-life. We must weigh the cost of marking up the original document against the benefits of having a variable-length on-line document.

The demo will consist of showing a document in full-length, and then selecting versions at different lengths. The settings can also be adjusted to allow different types of information to be favoured in pruning, so we can, for instance, place a higher emphasis on places and dates than on causes, reasons, etc.