Multi-Layered Browsing and Visualisationfor Digital Libraries

Alexander Weber1, Patrick Reuther1, Bernd Walter1,Michael Ley1, and Stefan Klink2

1 Department of Databases and Information Systems (DBIS),University of Trier, Germany

{aweber, reuther, walter, ley}@uni-trier.dehttp://dbis.uni-trier.de

2 Institute of Applied Informatics and Formal Description Methods,Universitat Karlsruhe (TH), GermanyStefan.Klink@aifb.uni-karlsruhe.dehttp://www.aifb.uni-karlsruhe.de

Abstract. For a scientific researcher it is more and more vital to findrelevant publications with their correct bibliographical data, not only foraccurate citations but particularly for getting further information abouttheir current research topic.

This paper describes a new approach to develop user-friendly inter-faces: Multi-Layered-Browsing. Two example applications are introducedthat play a central role in searching, browsing and visualising biblio-graphical data.

1 Introduction

The widespread use of computers for acquisition, production, and archiving ofdocuments lead to more and more information in electronic form. The ease withwhich documents are produced and shared has lead to an exponential increaseof information reachable by each user. More than 40 years ago, Maron andKuhns predicted that indexed scientific information will double every 12 years [4].Even in the academical area, new conferences, journals, and other publicationsare appearing quickly and they increase the huge amount of existing scientificpublications in an alarming manner, e. g., Cleverdon estimates the amount ofpublications of the most important scientific journals to 400,000 per year [1]and INSPEC, the leading English-language bibliographic information service, isgrowing at the rate of 350,000 records each year.

Finding relevant information within these masses of data is a challenging task.Particularly, in query based information systems like Yahoo, Lycos or Googleusers have severe problems even to formulate exact queries.

For the digital library domain where bibliographical data is the central infor-mation we developed a more user-friendly and efficient way for searching andbrowsing through bibliographical data by a combination of a query-based andbrowsing-based approach. Starting from an unspecific query users can browse

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through the bibliographical data by clicking items like authors, title words, con-ferences etc. As already indicated by [2] that users like the textual as well as thegraphical nature of information representation we enhanced the browsing-basedapproach by the so called Multi-Layered-Browsing. During the browsing processall data is visualised in a textual way and in parallel by appropriate graphicaltechniques which enables users to better understand their search domain andconsequently offers the opportunity to get an overview of their information needvery quickly. Furthermore, it helps them find relevant authors or publicationsand above all provides information about further researchers, important confer-ences or journals. The following chapters introduce the DBL-Browser and theML-Browser which support a searching and browsing-based approach within thebibliographical data.

2 Multi-Layered-Browsing

Most modern library systems offer only a very limited freedom to the user. Thereare only some very strict ways to search and to browse the data set. Most ofthe time a simple search mask is offered and the user has to browse through theresults in a mainly linear way. We are offering a better approach where the userhas multiple possibilities to go different ways on his search path. He does notneed to follow a strict path, but is flexible to choose the way that leads him mostefficiently to his goal. We call this concept Multi-Layered-Browsing: The user can– metaphorically speaking – change between different layers during his way onhis search path. These layers are always offering different possibilities to navigatefrom the current point to the next. To help the user even more, the layers donot only provide textual representations of the current visible data subset, butuse different graphical ways, so the user can choose what representation is bestfor his current information need. An example can be seen in fig. 1 with threedifferent ‘layers’ for a given author. The first layer (top-right) shows a textualrepresentation of the author’s publications, the second (bottom-left) shows thedata as a histogram and the third layer (bottom-right) shows the co-authorrelation as a graph. Our approach to support the user is to develop user-friendlyapplications, that focus on the user’s information need. The following sectionsintroduce two such tools: The Multi-Layer-Browser and the DBL-Browser.

2.1 The Multi-Layer-Browser

For testing this Multi-Layered-Browsing we developed the ML-Browser – a toolthat always shows different layers of the current data subset (see fig. 1). It isdesigned in such a way, that it is very easy to exchange the different visualisationswith own implementations or ideas. The author-view seen in fig. 1 can use aglobal filter-object that can be used for all layers, to only show the current focusof the user. That is, the user can for example select the year 2005 to filter outall co-authors that have not published in 2005 and to see a detailed histogram ofthe publications in 2005. If such a filter is not enough for shrinking the focus it

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Fig. 1. Overview of the ML-Browser

is possible to combine several filters. The visualisations make use of these filtersas well and can so provide a specially focused view of the data.

On the one hand the combination of layered browsing and chained filteringoffers the user a lot of ways to access the information he is searching for veryfast; on the other hand, the user can use these techniques to get a very goodoverview of the surroundings of the currently viewed data, thus enabling him tobrowse the social networks that exist in the data and helping him to broadenhis horizon.

2.2 DBL-Browser

The DBL-Browser was originally developed to browse textual visualisations ofthe DBLP. As the browser has evolved, so have the textual visualisations. Thebrowser now includes, in addition to author pages, textual visualisations of searchresults in tabular form, BibTEX pages, and Table of Contents (TOC) pages [3].These BibTEX and TOC pages allow users to continue to explore the knowledgedomain to find other relevant documents or related authors. The author pagesthemselves have also evolved, allowing for a clear, consistent layout of informa-tion across all textual visualisations. Besides textual visualisations we make useof user-friendly graphical visualisations, that support users in finding the desiredinformation. There are several things that make the DBL-Browser an easy-to-useapplication. One of the main aspects is it’s straightforward user interface. Ev-erybody using a common web-browser should be able to use the DBL-Browser.All essential features are at hand – like searching and filtering the data. The

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search system has all typical functions, with additional features such as com-bined searches or vague searches. The other main feature of the browser is theadditional navigation provided by the everything-is-clickable concept. So thereis a link on nearly every information shown in the browser – there are links toother authors, title-word searches, links to BibTEX pages, conferences, journals,or to the full-text electronic editions.

3 Conclusion and Encouragement

In this work a new approach for multi-layered browsing and visualisation for dig-ital libraries is introduced. In contrast to query-based information systems likeYahoo, Lycos, or Google our ML-Browser and in particular the DBL-Browserare user-friendly every-day applications which help the user to find relevantpublications and to browse through the bibliographical data by clicking items invarious levels. On basis of a high quality database the applications offer users amulti-layered browsing environment with support of various visualisations. Tex-tual representations, histograms and relationship graphs give a comprehensiveoverview of the current research area and relationships between authors. So in-teresting researchers can be found and contacted for exchanging information andinitiating further cooperations. The Multi-Layered-Browsing approach is aswellpredestined for analysing social networks regarding both author networks andconference/journal networks. This scientific area offers a lot of opportunities forfurther research.

Our intention is to provide the DBL-Browser as an open framework for ex-periments. Due to its modularisation, it is easy for anyone who is interestedto integrate own ideas and algorithms. The XML and compressed version ofthe DBLP data and the source code of the browser are available on our webserver: http://dbis.uni-trier.de/DBL-Browser/ Feedback and further ideasare also very welcome. Unfortunately it is far beyond our resources to includeall publications within the DBLP we are asked to consider. But we hope to findmore sponsors. . .

References

1. C. W. Cleverdon. Optimizing convenient online access to bibliographic databases.Information Services and Use, 4:37–47, 1984.

2. Y. Ding, G. G. Chowdhury, S. Foo, and W. Qian. Bibliometric information re-trieval system (BIRS): A web search interface utilizing bibliometric research results.Journal of the American Society for Information Science, 51(13):1190–1204, 2000.

3. S. Klink, M. Ley, E. Rabbidge, P. Reuther, B. Walter, and A. Weber. Browsing andvisualizing digital bibliographic data. In O. Deussen, C. D. Hansen, D. A. Keim,and D. Saupe, editors, VisSym, pages 237–242. Eurographics Association, 2004.

4. M. E. Maron and J. L. Kuhns. On relevance, probabilistic indexing and informationretrieval. Journal of the Association for Computing Machinery (JACM), 7(3):216–244, July 1960.