Increasingly, digital libraries are being defined that collect pointers to World-Wide Web based resources rather than hold the resources themselves. Maintaining these collections is challenging due to distributed document ownership and high fluidity. Typically a collection’s maintainer has to assess the relevance of changes with little system aid. In this paper, we describe the Walden’s Paths Path Manager, which assists a maintainer in discovering when relevant changes occur to linked resources. The approach and system design was informed by a study of how humans perceive changes of Web pages. The study indicated that structural changes are key in determining the overall change and that presentation changes are considered irrelevant.

We report on our first experiences in dealing with the retrieval of spoken documents. While lacking the tools and the know-how for performing speech recognition on the spoken documents, we tried to use in the best possible way our knowledge of probabilistic indexing and retrieval of textual documents. The techniques we used and the results we obtained are encouraging, motivating our future involvement in other further experimentation in this new area of research. Supported by a "Marie Curie" Research Fellowship from the European Community. Contents 1 Introduction 3 2 Probabilistic Information Retrieval 3 2.1 The binary independence retrieval model . . . . . . . . . . . . . . 4 2.2 Term weighting schemas . . . . . . . . . . . . . . . . . . . . . . . 9 3 The SIRE Information Retrieval system 11 4 The Abbot speech recognition system 12 5 Spoken document retrieval at TREC-6 14 6 The SDR TREC-6 data set 15 7 Experimenting probabilistic retrieval of spoken documents 18 7.1 The PFT wei...

The Web provides access to a wide variety of information but much of this information is fluid; it changes, moves, and occasionally disappears. Bookmarks, paths over Web pages, and catalogs like Yahoo! are examples of page collections that can become out-of-date as changes are made to their components. Maintaining these collections requires that they be updated continuously. Tools to help in this maintenance require an understanding of what changes are important, such as when pages no longer exist, and what changes are not, such as when a visit counter changes. We performed a study to look at the effect of the type and quantity of change on people's perception of its importance. Subjects were presented pairs of Web pages with changes to either content (e.g., text), structure (e.g., links), or presentation (e.g., colors, layout). While changes in content were the most closely connected to subjects perceptions of the overall change to a page, subjects indicated a strong desire to be notified of structural changes. Subjects only considered the simultaneous change of many presentation characteristics as important.

Data-driven identification of fixed expressions and their modifiability