Home Work on Information Retrieval

1. Let P be a set of points in 2-dimensional real space. Consider the problem of approximating the points in P using a 1-dimensional space. More precisely, we want to find a 1-dimensional subspace such that sum of the squares of the distances of the points in P to the 1-dimensional space is minimized. How do you determine such a 1-dimensional space? Generalize this to higher dimensions.
2. Explain how the NEAR operator in Altavista can be implemented efficiently.

Some Web Resources on Information Retrieval and Search Engines

• Authoritative Sources in a Hyperlinked Environment by Kleinberg; a highly recommended reading
• Information Retrieval by C.J. Van Rijsbergen is a good text book.
• How to Use Web Search Engines explains how search engines work and analyzes several popular search engines.
• Eureka! is an interesting search engine that claims to provide a uniform interface to various search engines.
• Also look under the Yahoo directory on Searching the Web for useful information.
• What do People want from Information Retrieval is an article by W. Bruce Croft discussing the top 10 research issues for companies that use and sell information retrieval products.