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_80619




α- nDCG is a variant of Normalised Discounted Cumulative Gain (nDCG). It is an evaluation measure for diversified search, where it is assumed that a topic q has multiple possible intents { i}, and that intent probabilities Pr( i| q) and per-intent relevance assessments are available. For a given diversified ranked list, let I i( r) = 1 if the document at rank r is relevant to intent i and let I i( r) = 0 otherwise; let \(C_{i}(r)=\sum _{k=1}^{r}I_{i}(k)\)
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© Springer Science+Business Media, LLC, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Waseda UniversityTokyoJapan