Displays of various pairs on Cartesian coordinates provides information on links being used, time of site visits, and the locations of visitors. With the addition of color and zooming and filtering capabilities, it is possible to explore data across several dimensions to reflect the current interests of the provider. Here, passages are constructed using Hearst's TextTile algorithm, where token sequences are conjoined into blocks that overlap with one another, and similarities between adjacent blocks are used to determine topic shifts, and thus the borders of two sets of blocks called tiles. These are supplemented by passages in the form of fixed length windows at 150 and 350 tokens, and discourse passages which use the document's paragraph or section structure. However, using the Wilcoxon signed rank test only a small number of the improvements are significant.
Passages based on pages most often show the strongest improvement.
Pivoted cosine similarity improves performance in collections where document length varies. The possibility of arbitrary fixed length passages was investigated by taking 12 window sets from 50 to 600 words, starting at 25 word intervals. Using only those passages containing the rarest query terms, similarities are computed for the passages and the query. In all test collections and for both short and long queries, fixed length arbitrary passages were found significantly superior to document rankings, but not significantly superior to predefined passages like pages. No particular length of passage appeared to have any advantage.