1. An Interactive System for CO-Citation Visualization Xia Lin Jan Buzydlowski Howard D. White Drexel University Philadelphia, PA, USA

2. Co-Citation a method for measuring the common intellectual interest between a pair of documents Small & Griffith (in 70’s) Later documents A, B, C, … Document 1 cites Document 2 ? cites

3. Author Co-Citation Insights into the intellectual structure of science and scholarship through citations over time. White & Griffith (in 80’s) Authors A, B, C, … Author 1 cites Author 2 ? cites

4. Author as an Icon An author –represents a person; –represents a body of writings. A group of related authors –comes to stand for a body of ideas –represents subject relationships of documents.

5. A Map of Information Scientists

6. Map Structures Retrieval Document User Citation (Bibliometrics) (Communication) (IR theories) (Online retrieval) (General)

7. Data for Information Scientists Map 120 highly cited authors in Information Science Co-citation count of every pair of the 120 authors A matrix of 120 by 120 of their co- citation counts, converted to Pearson r’s

8. Data Collection Labor-intensive process –Decided who are highest-cited authors in the field –Conducted thousands of DIALOG searches on paired authors C(120, 2) =7140 searches –Processed data in a spreadsheet White and McCain (JASIS, April 1998)

9. New Interactive System The challenges –To process data and generate the map instantly. –To provide interactive functions for the viewer to explore the map and the underlying data (with search engines). –To provide different maps (with different mapping algorithms).

10. The Database –Institute for Scientific Information –Arts and Humanities Database (AHCI) 1988 - 1997 1.26 million records –BRS search engines

11. The Old Interface

12. System Structure BRS Search Engines Web Server Java Servlets Web Interface Java Applet Mapping Procedures cgi

13. The New Interface

16. Authors co-cited most often with PLATO

17. Kruskal, Joseph B.

18. Kruskal, Clyde P.

19. Future Development Adding different maps –Pathfinders –Multidimensional scaling –Hierarchical clustering Adding more interactions with search engines –Mining and exploration tools –Subject labels