Proc. Int’l Conf. on Dublin Core and Metadata Applications 2009

Effectiveness of Query Expansion using Flickr Related Tags

JungWon Yoon
School of Library & Information Science, University of South Florida USA
jyoon@cas.usf.edu
Keywords:

social tagging; controlled vocabulary system; query expansion.

Abstract

Information retrieval is an iterative and interactive process. In other words, searchers who are
not satisfied with their initial search results revise their queries through addition, deletion, orchange of their search terms. Through the analysis of a 2001 Excite Web search log, the author
found that 26% of initial queries for image search were revised. Therefore, one possible approachfor enhancing image retrieval effectiveness would be to design an image retrieval system which
can guide users to reformulate their queries.
In the information retrieval field, query expansion (either automatic or end-user controlled) via
semantically related terms which are reflected on a thesaurus has been explored as a way of
improving search effectiveness (Efthimiadis, 2000; Greenberg, 2001). Although there are several
thesauri for image documents, there is no study which examines the effectiveness of thosethesauri for query expansion. In addition, since those thesauri are designed for specialized image
collections (art image, historical image, architecture, and so on), limitations of those thesauri forgeneral image collections has been discussed.
Recently, user-supplied tags received researchers’ attention as a user-centered indexingmechanism, and many studies have been conducted to investigate the potential and features ofuser-supplied tags. The author’s previous study (Yoon, in press) examined semantic features ofFlickr tags and their related tags,1 and demonstrated that semantic relations represented in Flickr
related tags have potential in expanding search queries and representing users’ unexpressed
image needs. The following support the authors’ suggestion:• Semantic relations represented in Flickr related tags showed that a concept holds
semantically related concepts not only in its own image attributes but also in otherattributes. For example, related tags for ‘Happy’ are ‘girl,’ ‘smile,’ ‘fun,’ ‘kids,’ and so on
and related tags for ‘birthday’ are ‘fun,’ ‘happy,’ ‘party,’ ‘cake,’ and so on.
• Comparison between the Library of Congress Thesaurus of Graphic Materials (LCTGM)
related terms (including NT, BT, and RT) and Flickr related tags demonstrated thatapproximately 10% of LCTGM related terms matched with Flickr related tags. Comparedto Flickr related tags, LCTGM related terms show more conceptually structured semantic
relations and include more conceptual, abstract and symbolic terms. It was also possible toobserve the potential of Flickr related tags. For instance, for a user who tried to query“Lazy,” which related terms would be more useful in finding images among “mentalstates,” “deadly sins,” “cat,” and “sleepy”? (The first two are from LCTGM and the last
two are from Flickr related tags.)
Therefore, even though Flickr related tags may not be alternatives of successions of traditional
indexing approaches, it is worthwhile to investigate how Flickr tags can be utilized in helping
users search image collections and be incorporated with traditional approach.
Based on the previous study results, the current study aims to demonstrate the effectiveness ofFlickr related tags for query expansion.

Although Flickr does not explain how related tags are created, it is apparent that related tags are generated
based on co-occurrence analysis (Specia & Motta, 2007).

1

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2009 Proc. Int’l Conf. on Dublin Core and Metadata Applications•••

RQ1: To what extent expanded queries through Flickr related tags are useful in improving
search effectiveness?
RQ2: Which are more useful in query expansion, BT, NT, and RT of LCTGM or Flickr
related tags?
RQ3: What are the characteristics of useful expanded queries during the image search
process?

For exploring the three research questions, two surveys and a post-interview are administered
to approximately 50 participants. First, participants are asked to provide image search queries
which could be sent to a search engine and to explain their search motivations. Then, by adopting
rules used in previous studies on query expansion (Greenberg, 2001; Kristensen, 1993), theresearcher manually extends each query using three Flickr related tags. Initial queries which
mapped with LCTGM are also expanded using BT, NT and RT. An initial query given by aparticipant and expanded queries are sent through Imagery, an image search engine, a set of 20
images are selected per each query, and each set of images are arranged to be fitted in one page ofscreen. Second, participants are asked to response the following questions: (1) which set ofimages is the most appropriate to your search, (2) which image is the most appropriate to yoursearch, and (3) which images are appropriate to your search (i.e., indicate images which would be
used for your search request). Third, a post-interview may be conducted if clearer explanations
are necessary.
References

Efthimiadis, Efthimis.N. (2000). Interactive query expansion: A user-based evaluation in a relevance feedbackenvironment. Journal of the American Society for Information Science, 51(11): 989-1003.
Greenberg, Jane. (2001). Automatic query expansion via lexical-semantic relationships. Journal of the American
Society for Information Science and Technology, 52(5), 402-415.
Kristensen, Jarvelin. (1993). Expanding end-user’s query statements for free text searching with a search-aid thesaurus.
Information Processing & Management, 29(6), 733–744.
Specia, Lucia and Enrico Motta. (2007). Integrating folksonomies with the semantic web. In Franconi, E., Kifer, M, &May, W. (Eds.), ESWC2007, LNCS 4519, 624-639.
Yoon, JungWon. (in press). Towards a user-oriented thesaurus for non-domain-specific image collections. Information
Processing and Management, (2009), doi: 10.1016/j.imp.2009.03.004.

134This article is licensed under a Creative Commons Attribution 4.0 International License,
which permits use, sharing, adaptation, distribution and reproduction in any medium or format,
as long as you give appropriate credit to the original author(s) and cite the source.

https://doi.org/10.23106/dcmi.952109661