Prof. Lois Delcambre(Professor from Computer Science Department, Portland State University) will give a talk titled "Bringing Structure to (Educational) Repositories (using techniques from databases and the semantic web)" on Wednesday, March 26 from 2-3pm in Aderhold Hall G23 Deans conference room.
Modern content management systems make it easy to build web-based repositories or digital libraries. Such systems often allow the user to create new content types consisting of any number of named fields; the fields might contain simple values (attributes), references to other content type instances (relationships), or references to files. Even when using the same content management system, repositories can differ in structure: some repositories may have a single content type (e.g.,resource) with associated metadata fields (e.g., Dublin Core metadata fields). Other repositories may define multiple content types, connected by relationships. We focus here on educational repositories where courses have a rich structure and where each course may have a different structure – based on the pedagogical approach used by the instructor. We seek to make it easy to develop generic widgets that will work for all courses, for example.
Our approach begins with the definition of small schema fragments that we call domain structures, where the domain structure describes (just) what is needed to support a widget of interest. For example, in order to support a hierarchical navigation widget, we use a domain structure with one entity (resource) with a single attribute (title), with a recursive relationship (part-of) that relates resources. Given a domain structure, we ask domain-savvy end-users to define simple correspondences from the components of the domain structure to their local structure. For example, a user might map resource (in the domain structure) to the local course content type, map resource, again, to the local unit content type, and the part-of relationship (in the domain structure) to the local units-in-course relationship. In effective, we seek to support end-user schema mapping. Once mapped, a user’s course appears in a full-featured navigation widget.
We have implemented these ideas in the Drupal content management system; we host several educational repositories with generic widgets that support navigation, (selective) cloning and downloading. The talk will demonstrate the features of our repositories including the widgets and a prototype mapping interface. The talk will also describe the way in which we have formalized this work as a form of database integration.
We have extended this work by defining a domain structure that supports dynamic, compound faceted browsing for repositories with simple structure. We envision using our technology over a set of sites (e.g., endpoints) using semantic web technology.
** This talk is sponsored by CS deparment, the Faculty of Robotics, and Department of Career and Information Studies in the College of Education at UGA.