Encyclopedia of Database Systems

2018 Edition
| Editors: Ling Liu, M. Tamer Özsu


  • Tetsuya SakaiEmail author
Reference work entry
DOI: https://doi.org/10.1007/978-1-4614-8265-9_80706


U-measure is a versatile evaluation measure. For a given textual information access task, U-measure first builds a trailtext, which is a concatenation of all the texts that the user has read (which may be constructed under some user behaviour model or based on some real evidence such as clicks and eyetracking or mousetracking data). Then, U-measure computes a score using a decay function based on the positions of relevant items within the trailtext. Formally, a trailtext tt is a concatenation of n strings: tt = s 1 s 2s n. The strings may be documents, parts of documents, snippets, sentences, or any other fragments of text that have been read. The offset position of s k(1 ≤ kn) is defined as \(\textit {pos}(s_{k})=\sum _{j=1}^{k}|s_{j}|\)
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© Springer Science+Business Media, LLC, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Waseda UniversityTokyoJapan