Abstract:

Ontology Based Personalized Search

A. Pretschner and S. Gauch


With the exponentially growing amount of information available on the Internet, the task of retrieving 
documents of interest has become increasingly difficult. Search engines usually report more than 1,500 
results for each query, yet out of the top twenty results, only one half turn out to be relevant to the user. 
One reason for this is that Web queries are in general very short and give an incomplete specification of 
individual users' information needs.This paper explores ways of incorporating users' interests into the 
search process to improve the results. The user profiles are structured as a concept hierarchy of 4,400 
nodes. These are populated by ``watching over a user's shoulder'' while he is surfing. No explicit feedback 
is necessary. The obtained profiles are shown to converge and to reflect the actual interests quite well. 
One possible deployment of these profiles is investigated: re-ranking and filtering search results. The 
increases in performance are moderate, but they are noticeable, and they show that fully automatic 
creation of large hierarchical user profiles is possible.