Similarity-Based Object Metadata Browser

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

2. Outline • Background • Problem • Concept • Concept Development • Implementation • Demonstration • Future Enhancements

3. 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) • http://flora.cs.ubc.ca:8080/learningobject

4. 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

5. 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

6. 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

7. 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

8. 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]

9. 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