Generating Concept Hierarchies from User Queries

  • Bob Wall
  • Neal Richter
  • Rafal Angryk
Part of the Studies in Computational Intelligence book series (SCI, volume 118)


Most information retrieval (IR) systems are comprised of a focused set of domain-specific documents located within a single logical repository. A mechanism is developed by which user queries against a particular type of IR repository, a frequently asked question (FAQ) system, are used to generate a concept hierarchy pertinent to the domain. First, an algorithm is described which selects a set of user queries submitted to the system, extracts terms from the repository documents matching those queries, and then reduces this set of terms to a manageable length. The resulting terms are used to generate a feature vector for each query, and the queries are clustered using a hierarchical agglomerative clustering (HAC) algorithm. The HAC algorithm generates a binary tree of clusters, which is not particularly amenable to use by humans and which is slow to search due to its depth, so a subsequent processing step applies min-max partitioning to form a shallower, bushier tree that is a more natural representation of the hierarchy of concepts inherent in the system. Two alternative versions of the partitioning algorithm are compared to determine which produces a more usable concept hierarchy.

The goal is to generate a concept hierarchy that is built from phrases that users actually enter when searching the repository, which should make the hierarchy more usable for all users. While the algorithm presented here is applied to an FAQ system, the techniques can easily be extended to any IR system that allows users to submit natural language queries and that selects documents from the repository that match those queries.


Feature Vector Feature Selection User Query Hierarchical Agglomerative Cluster Concept Hierarchy 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Springer-Verlag Berlin Heidelberg 2008

Authors and Affiliations

  • Bob Wall
    • 1
  • Neal Richter
    • 1
  • Rafal Angryk
    • 2
  1. 1.RightNow TechnologiesBozemanUSA
  2. 2.Montana State UniversityBozemanUSA

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