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Collaborative hypermedia

Collaborative hypermedia. Kaj Grønbæk InterMedia - Århus Aarhus University kgronbak@intermedia.au.dk. Plan. What is collaborative hypermedia Classical hypermedia systems supporting collaboration Collaboration support and the Web Open hypermedia - collaboration support for the web

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Collaborative hypermedia

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  1. Collaborative hypermedia Kaj Grønbæk InterMedia - Århus Aarhus University kgronbak@intermedia.au.dk

  2. 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

  3. 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

  4. 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

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

  6. 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

  7. 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

  8. 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

  9. 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

  10. 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

  11. Application Interfaces Application Interfaces Hypermedia Service Process Hypermedia Service Process Runtime Classes Runtime Classes Storage Classes Storage Classes (Storage Classes) (Storage Classes) HypermediaDataBase server HypermediaDataBase server 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)

  12. 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

  13. Subscription

  14. Notification and refetch of components

  15. Change of lock for a component

  16. Barriers for collaboration support on the WWW per se • WWW is primarily a publicing medium • WWW do not allow users to create links from andinto 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

  17. 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

  18. 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)

  19. 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:

  20. Open hypermedia basis architecture Applications • Collaboration on documents is coordinated by means of • Locking • Event notification • Versionning • A variety of modes for coupling users • Uncoupled • Loosely coupled • Tightly coupled Web Browsers Office apps. Office apps. Web server MS IE NS C Web server NavLets Webvise OHP Structure Proxy Server HSP Hyperstore JDBC/ ODBC

  21. 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

  22. Webvise - open hypermediaclient application • Tailored for Internet Explorer via COM

  23. Demo

  24. Arakne: Includes support for multimedia linking

  25. 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. Bouvin’s PhD project

  26. 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

  27. 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

  28. 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

  29. Mimicry substitutes plug-in with its own media controller

  30. 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

  31. Adding and visualizing linktypes in open hypermedia

  32. 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

  33. Spatial hypermedia Interface

  34. HM Server HM Client 3DManufaktur DirectX 3D Manuf.Server? Manufaktur Architecture ExternalApplications ActiveX COM Clients onlocal machine XML TCP/IP DCOM? NetworkedServers ODBC ODBC? PersistentStorage MIA PS MS Access

  35. Collaborative Hypermedia:research 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

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