CS 430 INFO 430 Information Retrieval

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CS 430 / INFO 430 Information Retrieval
Lecture 15 Usability 3
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Course Administration
Midterm Examination Collect answer books at end
of class or from reception at 301 College
Avenue Average grade 24.5/30 Assignment 2 We
hope to email the grades and comments this
afternoon. Assignment 3 Due Monday November
8 The assignment will be posted within the next
few days
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Course Administration
Seminar next Tuesday Amit Singhal,
Google Hollister B14, 430 to 530 This talk will
describe the challenges in running a very large
web search service, with hundreds of millions of
hits per day. Amit Singhal holds a Ph.D. from
Cornell computer science, where he was a student
of Gerald Salton
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BrowsingThe Human in the Loop
Return objects
Return hits
Browse repository
Search index
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Browsing in Information Space
Starting point
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Effectiveness depends on (a) Starting point (b)
Effective feedback (c) Convenience
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Convenience of Browsing
Rapid access to materials Physical objects
Library or large private collection Similar
items stored close together (classification) Onlin
e information Rapid delivery to desktop good
system performance no administrative delays
(authentication) Human skills and knowledge
augment and extend the automatic methods of
searching
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Convenience of Browsing
If the documents are accessible online, user can
browse content. This can compensate for
weaknesses in the underlying search system,
e.g., the difficulty of indexing Web
documents Otherwise, the user can browse
substitutes, e.g., catalog records, subject
hierarchies, etc. This puts heavy demands on
the precision of the underlying search
system
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Browse Catalog Record
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Hierarchical browsing
Level 0
Level 1
Level 2
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The Yahoo Interface
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The Yahoo Interface
The Yahoo interface is cluttered and
unattractive, yet Yahoo is one of the most
successful of all web sites. Why is this
interface successful? Very many branches from a
single web page saves the need for hierarchy of
menus. Simple html markup ensures that the page
renders quickly and accurately on all
browsers. Slow changes over the years means
that users are familiar with it. http//www.ya
hoo.com/
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Browsing the Content of Indexes
Show the users the terms that occur in indexes,
such as subject headings. Example Library of
CongressAmerican Memory http//memory.loc.gov/
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Broad categories
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Subject headings grouped
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Subject headings used in index
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Browsing by Filtering and Sorting
Filters allow users to reject categories of
information. Sorting by various criteria allows
users to organize information for rapid
scanning Example Research Libraries Group
Cultural Materials http//cmi.rlg.org/
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Browse everything
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Filter "New York"
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Sort "date"
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Information Visualization
Human eye is excellent in identifying patterns in
graphical data. Trends in time-dependent
data. Broad patterns in complex
data. Anomalies in scientific
data. Visualizing information spaces for
browsing.
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Alphabetic list http//nsdl.org/
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Graphical display http//nsdl.org/
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Visualization within Documents Tilebars
The figure represents a set of hits from a text
search. Each large rectangle represents a
document or section of text. Each row represents
a search term or subquery. The density of each
small square indicates the frequency with which a
term appears in a section of a document.
Hearst 1995
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Semantic Zooming Pad
Concept. A large collection of information
viewed at many different scales. Imagine a
collection of documents spread out on an enormous
wall. Zoom. Zoom out and see the whole collection
with little detail. Zoom in part way to see
sections of the collection. Zoom in to see every
detail. Semantic Zooming. Objects change
appearance when they change size, so as to be
most meaningful. (Compare maps.) Performance.
Rendering operations timed so that the frame
refresh rate remains constant during pans and
zooms.
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Pad File Browser
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Pad File Browser
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Pad File Browser