AuthorLink: AuthorLink: Instant Author Co-Citation Instant Author Co-Citation

Mapping for Online SearchingMapping for Online Searching

Xia Lin

Howard D. White

Jan BuzydlowskiXlin@drexel.edu

Drexel University

Philadelphia, PA, USA

Presented at the National Online Meeting Online 2001 At New York, May 15-17, 2001.

Author SearchAuthor SearchA tradition from library catalogs– Card Catalog– Online Catalog– Bibliographical Databases– Full text Databases

Two basic approaches for author searching– String matching in the author field– Alphabetical indexing/browsing

Problems of Author SearchingProblems of Author SearchingHow to search for related authors?– There are no easy solutions in most

current systems.The searcher usually needs to do a

lot of intellectual work to get to other related authors’ works

• Follow the citations• Follow the subjects

Our ApproachOur ApproachAlways show related authors during the

author search– Put the targeted author among relevant related

authors– Visualize how these authors are related to each

other– Use the author groupings to reveal subject

areas

A Map of Information Scientists A Map of Information Scientists

PlatoPlato

The AuthorLink SystemThe AuthorLink SystemBuilt on a significantly large database– ISI Arts and Humanities Database (AHCI)• 1988 - 1997• 1.26 million records

– Real time mapping and visualizingBased on two key methodologies – Author Co-Citation Analysis– Information Visualization

Co-CitationCo-Citation Co-citation is the mentioning of any two

earlier documents in the bibliographic references of a later third document.

Later Document 3

Document 1 cites

Document 2cites

Co-Citation AnalysisCo-Citation Analysis The count of mentions may grow over time

as new writings appear. Thus, co-citation counts can reflect citers’ changing perceptions of documents as more or less strongly related.

Documents shown to be related by their co-citation counts can be mapped as proximate in intellectual space.

Co-Citation MappingCo-Citation MappingDetects patterns in the frequency

with which any works by any two authors are jointly cited in later works.

Only recurrent co-citation is significant: The more times authors are cited together, the more strongly related they are in the eyes of citers.

ExampleExampleIf Ben Shneiderman and Shakespeare are cited

together in one article, it probably means little.If Ben Shneiderman and Stuart Card are cited

together in 205 articles,* it means a lot: their conjoined names have come to symbolize something like “interactive interfaces for digital libraries.” Possibly no subject heading captures this concept.

*Actual count, 7/10/00In a cited-author (CA) search on Dialog, SELECT CA=SHNEIDERMAN B AND CA=CARD SKwould retrieve the 205 citing articles.

Use DIALOG for ACAUse DIALOG for ACASelection of authorsRetrieval of co-citation frequenciesCompilation of raw co-citation

matrixConversion to a correlation matrixMultivariate analysis of correlation

matrix (using principle components analysis, cluster analysis, and multidimensional scaling).

The Old InterfaceThe Old Interface

The AuthorLink SystemThe AuthorLink System An integrated system that, in seconds,

– Finds and ranks 24 authors most often cited with seed author

– Pairs all ranked authors systematically, performs co-citation searches for all pairs, and generates a data matrix containing the results.

– Maps the co-citation counts in the matrix and generates interface maps for the user.• Kohonen self-organizing maps (SOMs)• Pathfinder Networks (PFNETs)

Live interface can be used to retrieve documents from AHCI that cite paired authors

Architecture of AuthorLinkArchitecture of AuthorLink

Front tier .. Middle tier .. Back tier

BRS Search EngineWeb Server

Java Servlets

Web-basedMap Interface

Java Applet

MappingProcedures

Application Server

OracleDatabase

MYSQL Database

Live System DemoLive System DemoAuthorLink

More Features of AuthorLinkMore Features of AuthorLinkAuthorLink presents an overview of a

field or a subject area.AuthorLink can distinguish similar

author names that are otherwise conflated in ISI data.

AuthorLink makes it easy for the user to explore intellectual territories from a single seed name, which minimizes cognitive load.

Overview Features of AuthorLink Overview Features of AuthorLink

Einstein-A and Mozart (Music)Einstein-A and Mozart (Music)

Einstein-A and Niels Bohr (Physics)Einstein-A and Niels Bohr (Physics)

AuthorLink helps to explore new territoriesAuthorLink helps to explore new territories

Beyond AuthorLinkBeyond AuthorLinkConceptLink–Maps medical subject headings (MeSH)– Uses PUBMED as the backend search

engine– Uses UMLS co-occurrence counts

JournalLink– Developed in the same database as

AuthorLink to visualize journal relationships

ConceptLinkConceptLink

Query: “back pain”Query: “back pain”

Live System DemoLive System DemoConceptLink

Future DevelopmentFuture Development

Stress browsability– AuthorLink and ConceptLink are not only

search tools but also exploration and discovery tools

Develop middleware and interfaces that can be linked to any search engine– All ISI databases– DIALOG databases– Web search engines