Multiuser Dynamic hypertexts with Programmable Browsing Semantics

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Multi-user Dynamic hypertexts with Programmable
Browsing Semantics
http//www.csdl.tamu.edu/caT/
Overview
Trellis

• Formal, Petri net-based specification
• Places map to content, transitions to links
• Multi-user, multi-browser hypertext documents
• Specifies the browsing behavior of hypertexts
• Separates
• structure from content
• presentation from content
• Formality allows analysis of structure
• Colored, timed Petri nets
• Colors represent users or roles
• Timed nets can browse themselves

• caT
• Introduces context-awareness in Trellis
• caT hypertexts respond to
• Characteristics of users
• Characteristics of environment
• Repeated viewing
• Passage of time
• Activities of other users

Token
(representation of user)
(contents are displayed)
Inactive Place
Active Place
(contents are hidden)
System Architecture
Enabled Transition
Examples
Disabled Transition
(link can be followed)

• Hypertexts that display different content at
  different times of the day
• - Outside of working hours, links to light
  reading may augment a collection of job-related
  reference materials
• Hypertexts that use different presentation
  mechanisms for different types of display
• - Customized text-based browser for readers with
  slow internet connections
• - Web-based interface for external readers
• - Audio browser for readers using cell phones
• Hypertexts that reflect the material seen
  previously
• - Rereading may change the content to include
  more details
• Hypertext that provide different services
  depending on availability of other users
• - Clicking on a help links may direct a reader
  to a human subject expert she is not occupied but
  to a computer-based reference database otherwise
• - Collaborative browsing behavior may be
  different than when a user browses the hypertext
  alone

Petri net constructs as hypertext features

• Server maintains the state of browsing
• Browsers render the information content
• Multiple clients can reflect the state of
  browsing to users
• Collaborative browsingVarious users may view and
  navigate a hypertext in parallel
• Browsers may join or leave during a browsing
  session without affecting other browsers
• caT supports media-specific browsers

Current Directions

• Browser Development
• To support new media typeswe currently support
  text, images, audio and video
• Understanding and addressing issues in
  simultaneous presentation of multiple audio/video
  elements
• To support a variety of behaviors,
  representations and metaphorsspatial browser
• Large hypertext Development Support
• Identification of higher-level authoring
  specifications
• Libraries of these structures will enable
  uniformity of structure across larger-sized
  hypertexts
• Parallel Browsing via Multiple Devices
• Find mechanisms to flexibly display content over
  different devices
• Customize the content and media type for
  achieving optimal effect on the target device
• Allow effects of user actions to propagate across
  devices

Browsers