Collaborative hypermedia Kaj Grnbk Inter Media rhus Aarhus

Collaborative hypermedia Kaj Grønbæk Inter. Media - Århus Aarhus University kgronbak@intermedia. au. dk Collaborative Hypermedia 1 Kaj Grønbæk

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 Collaborative Hypermedia 2 Kaj Grønbæk

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 • Concurrency control • who are allowed to do what? Event notification • transactions, locking, etc. Access control • uncoupled, loosely coupled, tightly coupled, . . . users are notified about important events Versionning • Content and structure history can be inspected Collaborative Hypermedia 3 Kaj Grønbæk

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 Collaborative Hypermedia 4 Kaj Grønbæk

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

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 Collaborative Hypermedia 6 Kaj Grønbæk

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 Collaborative Hypermedia 7 Kaj Grønbæk

Collaboration support in 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 Collaborative Hypermedia 8 Kaj Grønbæk

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 Collaborative Hypermedia 9 Kaj Grønbæk

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 Collaborative Hypermedia 10 Kaj Grønbæk

Collaboration support in Devise Hypermedia (AU) Server host User's workstation Application A Document management system Application B User's workstation Application A Browser Application B Browser ODHP Application Layer (Within Component Layer) ODHP Application Interfaces Hypermedia Service Process Runtime Classes Storage Classes Communication Layer Runtime Layer Storage Layer (Conceptual) Server host Collaborative Hypermedia (Storage Classes) Hypermedia Data. Base server 11 (Physical) Kaj Grønbæk

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 Collaborative Hypermedia 12 Kaj Grønbæk

Subscription Collaborative Hypermedia 13 Kaj Grønbæk

Notification and refetch of components Collaborative Hypermedia 14 Kaj Grønbæk

Change of lock for a component Collaborative Hypermedia 15 Kaj Grønbæk

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 Collaborative Hypermedia 16 Kaj Grønbæk

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 Collaborative Hypermedia 17 Kaj Grønbæk

Collaboration support on the Web Shared repositories • BSCW (GMD) • Lotus Notes/Domino Annotation systems • Com. Mentor (Stanford) • Crit. Link (www. critlink. org) • Third. Voice (www. thirdvoice. com) Open Hypermedia • Microcosm/Webcosm (Southampton) • Chimera (Boulder, Colorado) • Webvise and Arakne (Aarhus University) Collaborative Hypermedia 18 Kaj Grønbæk

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 Collaborative Hypermedia Link object 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: 19 Ændringsbekendtgørelse nr. 1053 af 18. juli 1997 om. . . Kaj Grønbæk

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

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

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

Demo Collaborative Hypermedia 23 Kaj Grønbæk

Arakne: Includes support for multimedia linking Collaborative Hypermedia 24 Kaj Grønbæk

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 Ph. D project Collaborative Hypermedia 25 Kaj Grønbæk

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 Collaborative Hypermedia 26 Kaj Grønbæk

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 Collaborative Hypermedia 27 Kaj Grønbæk

Arakne - Mimicry Use the generic Java. Media 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 Collaborative Hypermedia 28 Kaj Grønbæk

Mimicry substitutes plug-in with its own media controller Collaborative Hypermedia 29 Kaj Grønbæk

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 Collaborative Hypermedia 30 Kaj Grønbæk

Adding and visualizing linktypes in open hypermedia Collaborative Hypermedia 31 Kaj Grønbæk

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 Collaborative Hypermedia 32 Kaj Grønbæk

Spatial hypermedia Interface Collaborative Hypermedia 33 Kaj Grønbæk

Collaborative Hypermedia 34 Kaj Grønbæk

Networked Servers Clients on local machine External Applications Manufaktur Architecture HM Client Active. X XML TCP/IP 3 D Manufaktur COM Direct. X DCOM? HM Server 3 D Manuf. Server? ODBC Persistent Storage ODBC? Collaborative Hypermedia MIA PS MS Access 36 Kaj Grønbæk

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 Collaborative Hypermedia 37 Kaj Grønbæk