Additions to the slides+ next week's reading

1. I added three slides to the end of LSI to summarize the discussion we did connecting
LSI to LDA, feature selection and non-linear dimensionality reduction. I also added a slide
showing the reconstructed database/statistics example matrix for k=2 and 4.

2. For the next week, please read the first reference in Search Engine Technology.
Our plan over the next two weeks is to
1. discuss what it means to do IR in the context of Web pages.
2. notice that web pages--in addition to being text pages--also form a social network in terms of their hyper links
3. discuss social networks
4. apply social network analysis to web pages (authorities/hubs & page rank)

rao