Similarity-Based Object Metadata Browser Progress Report Rod McFarland CPSC 533C

Outline  Background  Problem  Concept  Concept Development  Implementation  Demonstration  Future Enhancements

Background  UBC Learning Object Metadata Repository What is a Learning Object?  Not what we usually consider “objects” to be Metadata Specifications: IMS, CanCore  XML schema for describing objects Web-based client interface (JSP/XML/MySQL)

Problem  Metadata provides flexible and comprehensive descriptions of general objects  Traditional search interfaces tend to offer searching on only a few descriptive dimensions  CanCore metadata specification has 41 non-placeholder elements – any of these could potentially be searchable

Concept  Use a browsing strategy based on “similarity” to a known object Define “similarity”  Depends on the data type (Language strings, dates, pure number, standard vocabularies)  How to handle varying multiplicity among metadata records Selection of known object  Via conventional text-based search  Via specification of “ideal” object

Concept  Originally envisioned a network view with pairs of objects of nonzero similarity linked by lines of length inversely proportional to the similarity. A bit of thought shows that this won’t work – without a lot of work, “similarity” is not a metric  New idea: similar objects radially arranged around known object, with distance inversely proportional to similarity

Concept Development  Similarity can be adjusted. As an aggregate measure, the component similarities can be given different weights  Selecting objects in the “cloud” will change the focus object and cause a new display to be generated  A “path” through the object space can indicate what objects have been visited

Implementation  Intended to be embedded in a Web page, so development will be in Java/Swing  Few available LO records, so modifying project to use a different source of objects (sentences in a text file) Since this was not intended to be a text browser, not offering a full-text view  [demo]

Future Enhancements (soliciting opinions and suggestions)  Prototype object to specify initial search focus  Color coding of dots to indicate most related dimension  Animated transition on focus object change  Make the “visited path” feature more useful – how?  Single-click or hover over object to see metadata detail  Change scale of display (by dragging mouse away from centre)  How to handle “ghost” objects  Negative weighting  Multiple options for computing similarity for a data type