Transcript WWW and InfoSphere - Georgia Institute of Technology

WWW and Internet
CS 7450 - Information Visualization
March 3, 2005
John Stasko
Internet and WWW
• By nature, abstract, so good target for
visualization
• Often described in terms of metaphors
 “Information Superhighway”
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Agenda
• Two main topics
 Presentations of the Internet and WWW
Focus on topology and navigation, similar to the
graph visualization work
 Visual aids for browsing and using the WWW
and the Internet
Assistive visualizations not focusing on presenting
net structure and connectivity
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1. Internet and WWW Topology
• Fundamentally, the Internet is a graph
with some existing physical topology,
though that is often not how we want to
conceptualize it
 Might think of it as having a structure
• Our discussions from graph visualization
are germane here
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The Problem
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Mukherjea & Foley
WWW ‘95
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The Problem
• Websites simply are too big
• Huge graphs
• Layout is challenging
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Step Back
• Why would someone want to visualize the
WWW?
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Some Reasons
• Aid authors and webmasters with
production and organization of content
• Assist Web surfers making sense of the
information
• Help researchers understand the Web
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Depictions of the Web
• Great web site that presents many
different conceptualizations of cyberspace
 Atlas of Cyberspace
http://www.cybergeography.org/atlas/
• Let’s take a few minutes to browse...
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Mapping the Internet
• Bill Cheswick at ATT
• Interesting visualizations plus the data
sets are available
• www.cs.bell-labs.com/who/ches/map/index.html
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Internet Traffic Paths
www.caida.org/tools/measurement/skitter/
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Mbone
Map
www.cs.berkeley.edu/~elan/mbone/map.html
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Immersive Systems
www.pnl.gov/remote/projects/starlight/
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View of Web Site’s Pages
www.dynamicdiagrams.com/
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Web Site
www.mos.ics.keio.ac.jp/NattoView
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Web Site Visitations
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www.inventix.com
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Task Analysis
• Potential web-related tasks
 How and when has info been accessed?
 Where do people enter and spend time?
 How do they move about?
 What paths aren’t traversed?
 Where are they coming from?
 What has been added, changed, deleted?
 Do changes affect navigation patterns?
 Do we need to do a redesign?
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Data Set
• Each server request is a data case
• Example variables
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IP Address/Client host
Timestamp
URL requested
HTTP status (success, not found, …)
Bytes delivered
Referencing URL (HTTP-Referrer)
User agent (browser and OS info)
...
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One Approach
• Use existing InfoVis tool (Eureka, Spotfire,
InfoZoom, etc.), load the data set, and
analyze it
• Get all the strengths and weakness of the
InfoVis tool for supporting particular
analysis tasks
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Web Ecology
• Problem: Most visualizations of the web
fail to present the dynamically changing
ecology of users and documents on the
web
• What do we mean by ecology metaphor?
Chi, et al
CHI ‘98
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Web Ecology
• By understanding set of relationships
(ecology) among users and their
information environment, and its change
through time (evolution) individuals can
better understand
 Web Content
 Layout of physical and topological space
 Usage through time
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Existing Visualizations
• Despite useful functions, problems
 Difficulty visualizing large number of
documents
 Considerable amount of screen real-estate
used
 Only permits the visualization of a site at a
particular point in time, very difficult to make
comparisons across times
 No mechanisms provided that allow
differences in usage to be identified
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Techniques
• Disk Tree
 Center-rooted tree that represents the
hyperlink structure of a web site
• Time Tube
 Set of disk trees that organizes and visualizes
the evolution of web sites
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Task Application
• Visualizations designed to be useful for
 Local - Finding specific content
 Comparison - Comparing info at two places
 Global - Discovering a trend or pattern in the
site
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Analysis Domain
• www.xerox.com, April ‘97
 7,588 items across a 30-day period
 889 new items
 Daily log kept of additions, modifications, and
deletions of content
 Base data comes from link info, usage log
from web servers
 Topological info from custom hyperlink
database
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Disk Trees
• Interested in shortest number of hops
from one document to another
• Breadth-first traversal transforms the web
graph into a tree by placing the node as
close to the root node as possible
• After obtaining this tree we then visualize
the structure using the Disk Tree
technique
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Disk Tree
Lines - tree links
Line size & brightness page access frequency
Color - page lifecycle stage
new: red
continued: green
deleted: yellow
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Advantages
• Structure is compact, with pattern easily
recognizable
• When viewed straight on or at slight
angles, no occlusion problems, since
entire layout is on a 2-D plane
• Unlike cone trees, this 2-D representation
can utilize a third dimension for other
information, such as time
• Circularity pleasing to the eye
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Time Tubes
• Time Tubes are multiple disk trees layered
out along a spatial axis
• Advantages
 By using a spatial axis to represent time, we
see information space-time in a single
visualization
 Focus and Context
 Possibility for Animation
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Time Tubes
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Key Point
• Pages there any time during the studied
period are shown in all disk trees for
period, even if they didn’t exist yet
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Real Use
• Time Tube answers following questions:
 What devolved into dead wood? When did it?
Was there a correlation with the restructuring
of the web?
Product safety pages got darker and darker,
indicating lower usage
Doesn’t tell why page is less popular, just raises a
flag to explore page further
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Real Use
• What evolved into a popular page? When
did it? Was there a correlation with the
restructuring of the Web site?
 Redesign of site called attention to Fact Book
page
 Became more popular and the corresponding
Disk Trees become greener and greener in
successive weeks
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Real Use
• How was usage affected by items added
over time?
 Press release issued for new family of
products, shown as red links
 Usage in the third week jumped from 1
access to 871 accesses, this example helps us
understand that this was probably a well
received product line
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Real Use
• How was usage affected by items deleted
over time?
 Change in removing direct link from home
page to main driver page did not negatively
affect the overall use of driver information
 Info stayed green indicating usage, but link
from home page was black, showing not
much traffic
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E-Commerce Applications
• What if your focus is on understanding
user access patterns for web sites selling
products to consumers?
• What tasks are important?
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One Approach
• Blue Martini Software
• Aggregate web data and visualize
simplified graph of user movements
through web site
• Highlight places where people leave
before purchasing
• ...
Brainerd & Becker
InfoVis ‘01
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Different icons represent
different kinds of pages
Only show most-used pages
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E-Commerce mimics
mall shopping :^)
Gender differences in
purchase paths at
websites
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2. Aiding WWW Browsing
• Can we utilize information visualization
techniques to help people interact with
the WWW and the Internet?
• Battle “lost in hyperspace” problem
• Help us know what’s there
• Help us find things
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WebBook and Web Forager
• Personal computers viewed as knowledge
processors before
 Spreadsheets and calculators
• Now viewed as knowledge sources,
portals to vast information worlds
 Networking and WWW
Card, Robertson and York
CHI ‘96
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WWW Problems
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Pages are hard to find
Users get lost, can’t relocate pages
Difficulty organizing things once found
Difficulty doing knowledge processing on
found thing
• Interacting with web is too slow to
incorporate gracefully into other activities
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Information Foraging Theory
• From Ecological Biology
• Idea: user stalks certain types of
information
• Users have tendency to interact
repeatedly with small clusters of
information (locality of reference)
• Information encountered at certain rate
 Users evolve to increase finding rate
 Sources evolve to be more attractive
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Mechanisms Evolved
• 3 mechanisms in the evolution of the web
on the server side
 Indexes - Lycos search
 Table of contents - Yahoo
 Home pages provided by users with big lists
of related links
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Assisting People
• To provide insight
 must support sensemaking
 restructuring
 recoding
• Hotlists are one mechanism in this
direction
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Improvements
• WebBook and Web Forager try to do two
things to foster information sensemaking
 Move away from a single web page, and
group and manipulate related pages
 Move from a work environment containing a
single element to a workspace in which the
page is contained with multiple other entities,
including Web Books
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WebBook
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Features
• WebBook allows for the rapid interaction
with object at a higher level of
aggregation than pages
• 3D book representation, uses animation
• Can ruffle through pages, leave
bookmarks
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Applications
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Hot List books
Topic books
Search reports
Book books
...
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Web Forager
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Web Forager
• Application that embeds the WebBook and
other objects in a hierarchical 3D
information workspace
• Workspace is intended to create patches
from the web where high density of
relevant pages (grouped together in Web
Books) can be combined with rapid access
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Constituents
• Hierarchical Workspace - 3 levels
 Focus Place - full page shown, direct
interaction
 Intermediate memory space - books or pages
placed when they are in use but not
immediate focus
 Tertiary space - Storage (bookcase)
Video
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Discussion
• Strengths/Weaknesses
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Data Mountain
• 3D document management system
• Prototype is an alternative to web browser
“bookmarks” or “favorites”
• Could be used for any kind of document
management
Robertson, et al
UIST ‘98
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Make-Up
• 3D inclined plane in which thumbnails of
web pages are placed to serve as
favorites
• User is responsible for organization
• Uses smooth animation and audio to
assist interaction
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Video
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User Study
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Data Mountain versus IE4 “Favorites”
Experienced IE4 users
Stored 100 pages, then retrieved them
DM fared about-as-well with “title” cue
DM fared better for all other cues
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Leveraging Human Capabilities
• Spatial memory: analogy with paper
placed on a pile on your desk
 User is responsible for personal organization
• 3D perception: minimal cognitive load,
good utilization of screen space
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Interaction Techniques
• Placing pages: confinement to inclined
plane makes normal 2D drag-and-drop
sufficient; no unfamiliar 3D navigation
needed
• Continuous feedback: both audio and
visual feedback are natural; minimized
unexpected interactions/surprises
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Limitations/Future
• Limits number of pages stored
• No explicit support for grouping
• Landmarks/contours as helpers
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Discussion
• Strengths/Weaknesses
• Could it be used elsewhere?
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Upcoming
• Trees & Hierarchies (2 days)
 Reading
Chapter 8
Lamping & Rao
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References
• Spence and CMS texts
• All referred to papers and websites
• McNamara & Defnet and Craighill,
Robeson & Sheridan F ‘99 slides
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