581257-8 Information retrieval methods - Exercises 3/2001 (14.2.)

        AD   0.9        EF   0.6        EB   0.3
        BD   0.8        AC   0.4        AF   0.2
        EC   0.8        AE   0.4        CD   0.2
        CF   0.7        BC   0.4        DE   0.1
        AB   0.7        BF   0.3        DF   0.1

2. (**) Make the same clustering as in task 1, using
a)'complete link', and b) 'group average' principle.

3. Read the main parts of the Scatter/Gather articles [1-3], and explain especially how clustering is done in this method ([2]). Article [3] contains additional material and article [1] (actually some www pages only) a general introduction to the method.

4. a) Compare the algorithmic clustering (especially using Scatter/Gather technique) and the ordinary classification (e.g. in Yahoo). What are the pros/cons of these techniques in retrieving information?

b) Documents could also be classified by some 'simple' attributes (author, publication time, language , etc.). Are these usable and how? Is it possible to combine the use of these with the other techniques?

References:

1. Xerox PARC: About Scatter/Gather. ( a href="http://www.parc.xerox.com/istl/projects/ia/sg-overview.html (introduction, examples, references)
2. Cutting, D.R. et al., Scatter/Gather: a cluster-based approach to browsing large document collections. ACM SIGIR'92, 318-329. (the original presentation of the method; the principles are given here)
3. Hearst, M. & Pedersen, J., Reexamining the Cluster Hypothesis: Scatter/Gather on Retrieval Results. ACM SIGIR'96, 76-84.