1 Kaj GrønbækCollaborative Hypermedia Collaborative hypermedia Kaj Grønbæk InterMedia - Århus Aarhus University [email protected]

1 Kaj GrønbækCollaborative Hypermedia

Collaborative hypermedia

Kaj Grønbæk

InterMedia - Århus

Aarhus University

[email protected]


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

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


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


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


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


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


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


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


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


Communication

User's workstation

Application A

ApplicationB

Browser

Hypermedia Service Process

Application Interfaces

Storage Classes

Runtime Classes

Application Layer

Layer

Storage Layer

(Physical)

RuntimeLayer

(Conceptual)

(WithinComponentLayer)

User's workstation

Application A

ApplicationB

Browser

Hypermedia Service Process

Application Interfaces

Storage Classes

Runtime Classes

ODHP

HypermediaDataBase server

(Storage Classes)HypermediaDataBase server

(Storage Classes)

ODHP

Document management system

Server host

Server host

Collaboration support in Devise Hypermedia (AU)


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


Subscription


Notification and refetch of components


Change of lock for a component


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


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


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)


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. 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:

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


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 serverOffice apps.

Applications

StructureServer

Hyperstore

OHP

Office apps.Web Browsers

MS IE NS C

NavLets

Webvise

HSP

JDBC/ODBC

Proxy

Web server


Component-based open hypermedia services

GeneralHypermedia

Database

GeneralHypermedia

Database

Navigationalservice

GeneralHypermedia

Database

Spatialservice

Annotational service

Taxonomicservice

Composite service

xxservice

NavLets

ApplicationsWeb Browsers

Open Hypermedia client

Office Apps

OHI

HDBI


Webvise - open hypermediaclient application

Tailored for Internet Explorer via COM


Demo


Arakne: Includes support for multimedia linking


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


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


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


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


Mimicry substitutes plug-in with its own media controller


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


Adding and visualizing linktypes in open 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


Spatial hypermedia Interface



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DirectX3D

Manufaktur

HM Server

3D Manuf.Server?

MS Access

XML TCP/IP DCOM?

ODBC?

ActiveX COM

MIA PS

ODBC


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

Documents

1 Kaj GrønbækCollaborative Hypermedia Collaborative hypermedia Kaj Grønbæk InterMedia - Århus Aarhus University [email protected]