1 Kaj GrønbækCollaborative Hypermedia Collaborative hypermedia Kaj Grønbæk InterMedia - Århus Aarhus University

2 Kaj GrønbækCollaborative Hypermedia 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 Kaj GrønbækCollaborative Hypermedia 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 Kaj GrønbækCollaborative Hypermedia 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 Kaj GrønbækCollaborative Hypermedia 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, SEPIA GMD-IPSI, Darmstadt, early 1990’ies Devise Hypermedia (DHM) Aarhus University, early 1990’ies

6 Kaj GrønbækCollaborative Hypermedia 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 ~leggett/engelbart.html

7 Kaj GrønbækCollaborative Hypermedia 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 Kaj GrønbækCollaborative Hypermedia 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 Kaj GrønbækCollaborative Hypermedia 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 Kaj GrønbækCollaborative Hypermedia 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 Kaj GrønbækCollaborative Hypermedia Communication User's workstation Application A Application B Browser Hypermedia Service Process Application Interfaces Storage Classes Runtime Classes Application Layer Layer Storage Layer (Physical) Runtime Layer (Conceptual) (Within Component Layer) User's workstation Application A Application B Browser Hypermedia Service Process Application Interfaces Storage Classes Runtime Classes ODHP Hypermedia DataBase server (Storage Classes) Hypermedia DataBase server (Storage Classes) ODHP Document management system Server host Collaboration support in Devise Hypermedia (AU)

12 Kaj GrønbækCollaborative Hypermedia 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 Kaj GrønbækCollaborative Hypermedia Subscription

14 Kaj GrønbækCollaborative Hypermedia Notification and refetch of components

15 Kaj GrønbækCollaborative Hypermedia Change of lock for a component

16 Kaj GrønbækCollaborative Hypermedia 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

17 Kaj GrønbækCollaborative Hypermedia 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 Kaj GrønbækCollaborative Hypermedia Collaboration support on the Web Shared repositories BSCW (GMD) Lotus Notes/Domino Annotation systems ComMentor (Stanford) CritLink ( ThirdVoice ( Open Hypermedia Microcosm/Webcosm (Southampton) Chimera (Boulder, Colorado) Webvise and Arakne (Aarhus University)

19 Kaj GrønbækCollaborative Hypermedia 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 I medfør af § 93, stk. 2 i bekendtgørelse nr 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: Ændringsbekendtgørelse nr af 18. juli 1997 om.....

20 Kaj GrønbækCollaborative Hypermedia 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 Web server Office apps. Applications Structure Server Hyperstore OHP Office apps. Web Browsers MS IENS C NavLets Webvise HSP JDBC/ ODBC Proxy Web server

21 Kaj GrønbækCollaborative Hypermedia Component-based open hypermedia services General Hypermedia Database General Hypermedia Database Na vigational service General Hypermedia Database Sp atial service An notational service Tax onomic service Co mposite service xx service NavLets Applications Web Browsers Open Hypermedia client Office Apps OHI HDBI

22 Kaj GrønbækCollaborative Hypermedia Webvise - open hypermedia client application Tailored for Internet Explorer via COM

23 Kaj GrønbækCollaborative Hypermedia Demo

24 Kaj GrønbækCollaborative Hypermedia Arakne: Includes support for multimedia linking

25 Kaj GrønbækCollaborative Hypermedia 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 Kaj GrønbækCollaborative Hypermedia 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 Kaj GrønbækCollaborative Hypermedia 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 Kaj GrønbækCollaborative Hypermedia 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 Kaj GrønbækCollaborative Hypermedia Mimicry substitutes plug-in with its own media controller

30 Kaj GrønbækCollaborative Hypermedia 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 Kaj GrønbækCollaborative Hypermedia Adding and visualizing linktypes in open hypermedia

32 Kaj GrønbækCollaborative Hypermedia 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 Kaj GrønbækCollaborative Hypermedia Spatial hypermedia Interface

34 Kaj GrønbækCollaborative Hypermedia

36 Kaj GrønbækCollaborative Hypermedia Manufaktur Architecture External Applications Clients on local machine Networked Servers Persistent Storage HM Client DirectX 3D Manufaktur HM Server 3D Manuf. Server? MS Access XML TCP/IPDCOM? ODBC? ActiveXCOM MIA PS ODBC

37 Kaj GrønbækCollaborative Hypermedia 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