Peter Bergström, “Augmenting digital libraries using web-based visualizations,” Master’s thesis, Santa Clara University, Department of Computer Engineering, June 2009.
Abstract
Web-based digital libraries have sped up the process that scholars use to find new, important research papers. With powerful searching capabilities and rich bibliographic meta data, a digital library is a great resource. Unfortunately, current digital libraries are limited by their inadequate webpage-based paradigm, and it is easy for even the most experienced scholar to get lost in the vast quantity of published material available. A paper and its immediate references are shown on a webpage, but it is not obvious where that paper belongs in the larger context of a field of research.
The main goal of our research was two-fold. First, to develop and test the effectiveness of an application that can augment a scholar’s interaction with a digital library and explore bibliographic meta data using a defined set of visualizations. These visualizations needed to provide different levels of visibility into a paper’s citation network without losing focus of the currently viewed paper. The application, called PaperCube, needed to support navigation between papers and, to a limited extent, the authors of those papers. The application needed to be able to provide insight into author to author citation networks as well as collaboration relationships.
The hypothesis was that by replacing the traditional webpage-based paradigm with a suite of visualizations that expose various dimensions of bibliographic meta data, the a researcher could gain new insights and find relationships that were not previously apparent. Furthermore, by making the experience spatial, the aim was to see if researchers were able to find what they were looking for more quickly and intuitively. The second goal was to push the limits of modern web browsers. By using web standards-based technologies, the goal was to explore the possibility of creating a dynamic, desktop-like experience that incorporates rich, interactive visualizations.
PaperCube was written using the SproutCore JavaScript framework, which is geared towards the creation of highly interactive, cloud, or thick-client applications in the web browser. Using only JavaScript and standards-based rendering technologies such as Scalable Vector Graphics, Canvas tag, HTML and CSS, PaperCube allows users to browse a version of the CiteSeer digital library and view paper and author relationships using a set of dynamic visualizations.
Leveraging the powerful features in SproutCore including bindings and observers, PaperCube aims to deliver unparalleled interactivity within the confines of a web browser. Bindings and observers enabled PaperCube to easily implement resolution independence in its visualizations. Resolution independence was key because citation networks can be very large. By adjusting a slider control in the UI, a visualization can be zoomed in using vector-based transforms without needing to explicitly redraw. Furthermore, through the use of bindings, slider controls can dynamically alter the display parameters of the visualizations, permitting the depth of a paper citation network to be adjusted or the thresholds that determine if a node should be displayed as part of the graph changed.
Stemming from the need for a flexible graph API for various views in PaperCube, the SVG-based NodeGraph class was created as a generalized solution that can display any type of relational data as an undirected graph. The class is not PaperCube-specific and could be easily integrated into other applications. PaperCube was validated through a user study which showed that it was very useful when it comes to augmenting digital library search by reducing the “cognitive load” put on a scholar and aiding the “discoverability” of new research material. Furthermore, it was shown that participants thought that it was “visually exciting and intuitive” application and an “amazing example of the apps that well be seeing on the web in a couple of years.”
[Full text in PDF]