Collaborative hypermedia

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Collaborative hypermedia

• Kaj Grønbæk
• InterMedia - Århus
• Aarhus University
• kgronbak_at_intermedia.au.dk

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Plan

• What is collaborative hypermedia
• Classical hypermedia systems supporting
  collaboration
• Collaboration support and the Web
• Open hypermedia - collaboration support for the
  web
• Advanced structuring mechanisms
• Future directions and conclusion

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Collaborative hypermedia

• Support for sharing and coordination of work with
  multimedia information
• content as well as hypermedia structures
• Both asynchronous and synchronous collaboration
  support
• range from plain sharing of webpages to online
  shared editing
• Different modes of collaboration
• uncoupled, loosely coupled, tightly coupled, ...
• Concurrency control
• transactions, locking, etc.
• Access control
• who are allowed to do what?
• Event notification
• users are notified about important events
• Versionning
• Content and structure history can be inspected

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Collaborative hypermedia - potential application
domains

• Examples
• Engineers and designers working with sketches,
  drawings, and documentation
• Supervisors, journalists, teachers etc., who
  digest and communicate material made by others
• Digital libraries and museums used by researchers
  and students for their projects
• Communities and non-governmental organisations
  who collect, and discuss various bodies of
  information

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Collaboration support in early hypermedia systems

• NLS/Augment
• Stanford Research Centre 1960ies
• KMS
• CMU (ZOG) and Knowledge Systems Inc. (KMS) in the
  1980ies
• Intermedia
• Brown University in the 1980ies
• EHTS
• Emacs HyperText System, Aalborg University,
  1989-91
• SEPIA
• GMD-IPSI, Darmstadt, early 1990ies
• Devise Hypermedia (DHM)
• Aarhus University, early 1990ies

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Collaboration support in NLS/Augment

• Electrionic mail
• supports mailing of Augment documents
• Journalization system for mail
• documents frosen and stored in shared database
• Shared screens and desktop conferencing
• entire screen can be replicated to other users
• parallel phone connection for communikation
• control over documents can be transferred between
  users

http//www.csdl.tamu.edu/leggett/engelbart.html
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Collaboration support in KMS

• Multiple users can edit the same frameset and
  even the same frame (approx on page of
  text/graphics)
• optimistic concurrency control to avoid locking
• when conflicts occur the first who saves win, the
  rest have to save copies
• frame owner can protect a frame from editing
• transparent annotation items which do not print
• Versionning
• hierarchy (e.g. a paper) can freezes into a
  version
• when a frosen frame is being edited a new copy is
  created automatically
• action programs can be used to process versions

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Collaboration support in Intermedia

• Intermedia Web a collection of links and blocks
• link and block information stored separat from
  content
• webs are stored in a conventional database
• easy to change context
• same document can be used in many contexts, i.e.
  many webs
• Collaboration
• multiple users can create and follow links in the
  same web
• read, write and annotation rights
• annotation means that you can link to the
  document but not modify it

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EHTS (Aalborg University)

• General hypertext-based multiuser editing system
• client-server system
• database server, text editor client, graphical
  browser client
• Relaxed WYSIWIS user interface
• placement of windows
• browser layout
• content update
• Concurrency control
• Event notification
• Access control

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Collaboration in SEPIA

• Similar to EHTS
• locking, events, graphical browser
• Seamless transition between different modes for
  collaboration
• uncouples mode work on separate parts of shared
  material
• loosely-coupled mode awareness notifications,
  handles conflicts and coordinering
• tightly-coupled mode synchronous collaboration,
  shared environment

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Collaboration support in Devise Hypermedia (AU)
Server host
Document management system
User's
User's
workstation
workstation
Application Layer


ApplicationB
ApplicationB
Application A
Application A
(Within
Component
Layer)


Browser
Browser
ODHP
ODHP
Communication
Layer
Runtime
Layer
Storage
Layer
(Conceptual)
Server host

(Physical)
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Collaboration facilities

• Event notifications
• Creation/modification/deletion of hypertexts
• Creation/modification/deletion of individual
  components
• Creation/modification/deletion of anchors
• Lock changes for entire hypertexts and components
• Users subscribe to event notifications for
  actions by all users, a group of users, an
  individual user
• Users choose an update strategy manual update,
  automatic (immediate update)
• Session management
• Long term transactions
• locking

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Subscription
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Notification and refetch of components
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Change of lock for a component
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Barriers for collaboration support on the WWW per
se

• WWW is primarily a publicing medium
• WWW do not allow users to create links from and
  into materials they do not own
• WWW documents need to be modified to create links
  
• WWW do not support user controlled organization
  of documents in other categories or hierarchies
  than those created by the author
• WWW do not support coordination of collaboration
  on documents being worked on

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Tim Berners-Lee - the creator of WWW -about the
future

• Goal Intercreative space
• As you can read, so can you write
• If you notice a connection, make a link
• Collaborative editing research done, products
  nowhere?
• Software hard
• Needs authentication, PUT, catch lost update,
  version management, etc..
• Amaya Jigsaw progress

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Collaboration support on the Web

• Shared repositories
• BSCW (GMD)
• Lotus Notes/Domino
• Annotation systems
• ComMentor (Stanford)
• CritLink (www.critlink.org)
• ThirdVoice (www.thirdvoice.com)
• Open Hypermedia
• Microcosm/Webcosm (Southampton)
• Chimera (Boulder, Colorado)
• Webvise and Arakne (Aarhus University)

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Open hypermedia for the WWW

• Users may create their own structures (links,
  collections, annotations etc.) on the Web
• Structures stored in separate databases
  (contexts)
• Many layers of structure on top of the same Web
  documents
• Users may apply one or more layers at a time

Link object

• Ændringsbekendtgørelse nr. 1053 af 18. juli 1997
  om .....

I medfør af 93, stk. 2 i bekendtgørelse nr.
1053 af 18. december 1995 om levnedsmiddelhygiejne
og egenkontrol m.v. og 20, stk. 2 i
bekendtgørelse nr. 931 af 6. december 1995 om
materialer og genstande bestemt til at komme i
berøring med levnedsmidler fastsættes
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Open hypermedia basis architecture

• Collaboration on documents is coordinated by
  means of
• Locking
• Event notification
• Versionning
• A variety of modes for coupling users
• Uncoupled
• Loosely coupled
• Tightly coupled

Applications
Web Browsers
Office apps.
Office apps.
MS IE
NS C
Web server
Web server
NavLets
Webvise
OHP
Structure
Proxy
Server
HSP
Hyperstore
JDBC/
ODBC
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Component-based open hypermedia services
Applications
Web Browsers
Office Apps
NavLets
Open Hypermedia client
OHI
Navigationalservice
Spatial service
Annotational service
Taxonomicservice
Composite service
xxservice
HDBI
GeneralHypermedia Database
GeneralHypermedia Database
GeneralHypermedia Database
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Webvise - open hypermediaclient application

• Tailored for Internet Explorer via COM

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Demo
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Arakne Includes support for multimedia linking
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The Arakne collaboration interface

• Aim support collaboration by providing shared
  awareness through a low impact interface
• Main interface components
• Session management
• Tickertape for notifications
• Subscription dialogs
• Acknowledgement N.O. Bouvins PhD project

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Examples of tightly coupled collaboration

• Synchronised Web-browsing
• Web-forum
• Distributed education
• Collaborative authoring of web-news and
  journals
• Production of a newsletter - on-line outline
  discussion
• Review and versionning of documents
• Project work in education
• Collaborative search, reflection and writing

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Examples of advanced open hypermedia services

• Well-known services
• Linking, annotations and guided tours
• Developed recently
• Linking in multimedia data on the Web - Mimicry
• Spatial hypermedia
• Typed links

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Arakne - Mimicry

• Use the generic JavaMedia framework to present
  various media types
• Proxy server replaces embeddings and links to
  movies, sounds etc. with a call of an applet
• A controller applet provides the interface to
  selecting video segments

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Mimicry substitutes plug-in with its own media
controller
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Link types in open hypermedia

• Types are used to distinguish among links with
  different semantic meaning
• Examples
• Teachers may use link types such as
  "introductory", "experienced", and "advanced" to
  distinguish sources based on the knowledge
  required to read them.
• They may discuss the quality of the sources, by
  introducing link types such as "recommend as
  primary reading", "recommend as background
  reading", "useless" etc.
• The teachers may use the type mechanisms to
  generate filtered browsers, e.g. with an overview
  of which of their subjects they have found
  "recommended primary readings" for

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Adding and visualizing linktypes in open
hypermedia
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Spatial hypermedia

• Relationships are implicit through proximity
• Like stacks of paper on a desktop
• Information analysis
• Query postprocessing
• Digital library application for students
• Sorting results of queries

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Spatial hypermedia Interface
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Manufaktur Architecture
ExternalApplications
ActiveX
COM
Clients onlocal machine
XML TCP/IP
DCOM?
NetworkedServers
ODBC
ODBC?
PersistentStorage
MIA PS
MS Access
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Collaborative Hypermediaresearch issues

• Developing a general extensible infrastructure
• with built-in collaboration support
• Open set of "structure servers"
• each (conceptual) server provides a set of
  structural abstractions
• data model extensibility
• Open set of behaviors
• "plug-in" to structure servers
• provide structural computation (e.g. traversal
  semantics)
• Provide distribution/scalability that matches Web
  usage
• Web integration and easy access.
• Use meta-data perspective on open hypermedia
  structures