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Interfaces for Selecting and Understanding Collections. Selecting from Collections. Collections are sets of documents that have been coalesced by a human or system. Traditional collections: NLM’s MedLine ACM Digital Library LEXIS-NEXIS Library/museum resources from a particular donor - PowerPoint PPT Presentation
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Interfaces for Selecting and Understanding Collections
Selecting from CollectionsCollections are sets of documents that have
been coalesced by a human or system.Traditional collections:
– NLM’s MedLine– ACM Digital Library– LEXIS-NEXIS– Library/museum resources from a particular
donorHow do people with information needs
locate and identify the appropriate collections?
Does it Matter?Web search engines (e.g. Google) get us the
information we need …– well maybe
Web search drops users into the middle of a collection without any understanding of the collection and its overall characteristics.
Web search misses– Lots of more structured materials
• “the hidden web”– Subscription-based content
• Which is likely the best edited, most accurate, and most valuable in specialized domains
Interfaces over Multiple Collections
Interfaces for Selecting and Understanding Collections– Lists– Overviews– Examples– Automated source selection
Lists of Collections
Usually just provides a list of collection names.– Difficult to select from if user does not know
the collections beforehand– Over time people bookmark collections of
value
Need tools for helping users who are outside of their areas of expertise
Example
Example
Examples
Overviews of Collections
Overviews provide a sense of what is in a collection
Overviews can be– Based on a category or directory structure– Automatically derived from the collection
Presentation of an overview is often a form of information visualization
Category-based Overviews
MedLine – biomedical collection– Medical Subject Headings (MeSH) consists of 18,000
categories in a directed acyclic graph
ACM Digital Library – computer science collection– Hierarchy of 1200 catgory (keyword) labels
Yahoo – the Web– Graph of directories (probably a DAG)
Humans have to place documents in categories– Author for ACM DL, subject experts for MedLine,
surfers for Yahoo
MeSH Browser
HiBrowse Browser
ConeTrees
Radial Views
Hyperbolic Views
MediaMetro
Automatically Derived OverviewsApply clustering algorithms to document collection
– Remember Automatic Global Analysis• Use of co-occurrance and co-citation• Use of distance-based clustering approaches like hierarchic
agglomerative clustering
Need methods to determine labels for clusters– Could be a document
• identification of centroid (document most similar to all others)• Identification of hubs (document most mentioned by cluster)
– Could be one or more terms• Use most common / best differentiator (using TF-IDF)
No human intervention required – but people are likely to be valuable as editors
Scatter Gather
Evaluation of Scatter-Gather
Scatter-Gather– Scatter-Gather conveyed overview of
collection contents– Scatter-Gather without search was less
effective than a basic search– Need to combine clustering with search
Themescapes
More Themescapes
Kohonen Maps
Evaluation of Graphical OverviewsOne study found that non-experts found the
clustering results difficult to use (worse than text-based views like Scatter-Gather)
Comparison of Kohonen map and Yahoo– 11 of 15 subjects found “interesting” page using
Kohonen• 8 were able to find same page using Yahoo
– 14 of 16 subjects found “interesting” page using Yahoo
• 2 were able to find same page using Kohonen– Subjects liked ability to jump between categories
without backing out of current categoryUnsupervised thematic overviews probably better
for giving a gist of what is in a collection than for search.
Examples, Dialogs, WizardsRetrieval by reformulation
– Start with example queries• Rabbit, Helgon
– Can be difficult to find appropriate starting queryWizards
– Found to be helpful for users without necessary domain knowledge get through many step processes
– Not helpful when wizard not accompanied with help– Not useful when goal is teaching how to use the interface.
Guided tours– Presents a logical sequence of navigation choices for
accomplishing a goal (e.g. Waldens Paths)– Not evaluated with regards to information access
Automated Source SelectionSelecting collection automatically (but explicitly)Need a model of each collection
– What it covers, need model of topics– What it is good at, need metric for good
Develop a model of the user’s information needMatch the information need to the most valuable
collections for that topicUsed in meta-search – interesting area of
researchCould be starting point for interactive collection
selection.