Perception of Content, Structure, and Presentation Changes in Webbased Hypertext

1
Perception of Content, Structure, and
Presentation Changes in Web-based Hypertext

• Luis Francisco-Revilla Frank M. Shipman
  IIIRichard Furuta Unmil Karadkar Avital Arora
• Center for the Study of Digital Libraries Texas
  AM University

2
What is this talk about?

• When dealing with Web-based hypertext, due to its
  fluid nature, it is continuously required to
  locate and identify meaningful changes
• but what changes do people find meaningful?
• We conducted a study to observer how type and
  magnitude affected the human perception and
  assessment of changes on Web pages
• how to use this observations in systems that can
  aid people?
• We created the Waldens Paths Path Manager that
  attempts to use this knowledge in order to assess
  the relevance of the changes

3
This is a problem everybody has

• Bookmark lists
• Yahoo! catalogues
• Meta-document applications such as Waldens Paths

4
Managing Waldens Paths collection

• Paths are meta-documents
• Sequential arrangement of Web pages
• Rhetorically coherent
• Contextualized
• Distributed ownership
• Distributed authorship
• Continuous revision of the collection

5
Mechanisms for addressing the issue

• Caching the pages
• Caching strategies (CiteSeer, AltaVista)
• Some changes are desirable (CNN, Weather)
• Fluid paths
• Ephemeral paths
• Rhetorical coherence

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The real issue

• Mechanisms only allowed limited reaction to
  changes
• Detecting changes is easy but determining the
  relevance is difficult
• Humans are still required to determine the
  significance of changes
• In order to react to changes the assessment of
  their relevance is required

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The perception of change

• Observe how humans perceive changes of Web pages
• Inform and evaluate the approach and design
• Questions
• Do people view the same changes in a different
  way when given different amounts of time?
• What kind of changes are easily perceived?
• Of what kind of changes do users want to be
  notified?

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Kinds of change

• Content changes (what)
• Presentation changes (how)
• Structural changes (linking)
• Behavioral changes (dynamic)

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The participants

• 18 adults
• Mostly Texas AM students
• Ranging from humanities to sciences
• Levels from undergraduate to post doctoral
• Divided into group A and group B

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The study

• Participants acted as Information Facilitator in
  a K-12 school. Their responsibility was to check
  the Web pages used by other teachers and notify
  them whenever important changes occurred.
• Participants were presented with two version of a
  Web page in two adjacent monitors
• Participants were asked to evaluate the change
  magnitude and their relevance

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The source materials

• Mostly selected out of existing paths
• A modified version was created to reflect a
  single type of change

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Methodology

• Familiarization with testing software and
  definitions of change
• Pre-evaluation questionnaire
• Phase I (8 pages _at_ 60 sec/page)
• Phase II (31 pages _at_ 15 sec/page)
• Phase II (31 pages _at_ 60 sec/page)
• Post-evaluation questionnaire

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Questions

• From the Content perspective, the degree of
  change is
• From the Structure perspective, the degree of
  change is
• From the Presentation perspective, the degree of
  change is
• Overall, how significant are the changes?
• If this page were in my bookmark list, I would
  like to be notified when changes like these occur
• Questions 1-4 were answered in a 7-point scale
  ranging from none to moderate to drastic
• Question 5 was answered in a 7- point scale
  ranging from strongly disagree to strongly
  agree

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Results phase I
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Results content and structure
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Results presentation
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Implications

• Presentation changes were usually perceived as
  irrelevant
• The desire of notification and the perception of
  overall change increased as the degree of content
  change did
• Time played a larger role for the perception of
  structural changes than for the content changes
• As the degree of structural change increased, so
  did the desire of notification
• Links are useful metrics

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Path Manager the system

• Java based
• Paths or bookmark lists
• HTML pages
• Functional state of the document
• Original
• Valid
• Last-time

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Algorithms

• Variation of Johnson
• Weighted sum of additions, deletions and
  modifications for each metric
• Added metric for structure changes
• Flexible
• Asymmetric
• Lack normalization

• Proportional
• Determines the proportion of modification for
  each metric
• Simple
• Symmetrical
• Normalized

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• Initial interface

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• Overall change relevance assessment

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Document signatures

• Paragraph checksums
• Headlines
• Links
• Keywords
• Global checksum

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• View of change metrics

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• Detailed view of page metrics

25

• Path information

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Web page retrieval and connectivity

• Potentially slow and unpredictable
• Parallel retrieval
• Multi-threaded
• Multiple attempts and retries
• Different states
• Connection state
• Retrieval state
• Analysis state

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Future Work

• Evaluate alternative metrics and algorithms
• Evaluate the Path Manager with different
  collections

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Conclusions

• The study help to understand what people consider
  relevant changes
• The study revealed that structural changes should
  be included in the determination of change
  relevance
• The study also show that content changes are
  highly related to overall magnitude and relevance
• The results obtained help to guide the design of
  the Path Manager

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Contact information

• Luis Francisco-Revilla
• l0f0954_at_csdl.tamu.edu
• Frank M. Shipman, III
• shipman_at_csdl.tamu.edu
• Richard Furuta
• furuta_at_csdl.tamu.edu
• Unmil Karadkar
• unmil_at_csdl.tamu.edu
• Avital Arora
• avital_at_csdl.tamu.edu