Web Similarity in Sets of Search Terms using Database Queries
This work provides a method for semantic analysis in information retrieval and machine learning, but it appears incremental as it extends earlier normalized google distance to sets.
The paper tackles the problem of measuring semantic similarity for sets of search terms using normalized web distance (NWD), which approximates similarity based on computable properties from large databases like Wikipedia and Amazon, with applications in classification and health hazard correlation.
Normalized web distance (NWD) is a similarity or normalized semantic distance based on the World Wide Web or another large electronic database, for instance Wikipedia, and a search engine that returns reliable aggregate page counts. For sets of search terms the NWD gives a common similarity (common semantics) on a scale from 0 (identical) to 1 (completely different). The NWD approximates the similarity of members of a set according to all (upper semi)computable properties. We develop the theory and give applications of classifying using Amazon, Wikipedia, and the NCBI website from the National Institutes of Health. The last gives new correlations between health hazards. A restriction of the NWD to a set of two yields the earlier normalized google distance (NGD) but no combination of the NGD's of pairs in a set can extract the information the NWD extracts from the set. The NWD enables a new contextual (different databases) learning approachbased on Kolmogorov complexity theory that incorporates knowledge from these databases.