Ubiquitous Access for Collaborative Information System
Sangmi Lee1, Geoffrey Fox2, Sunghoon Ko3, Minjun Wang4, Xiaohong Qiu5
Department of Computer Science
Florida State University, USA
Department of Computer Science
Indiana University, USA
Pervasive Technology Laboratory
Bloomington, IN, USA
Department of Electrical Engineering and Computer Science
Syracuse University, USA
There are growing opportunities for collaborative use of hand-held and desktop devices. In education students can use PDA's with real-time collaborative digests of a lesson to make notes. In research, mixing of PDA and conventional interfaces to computers provides new research environments. We have designed and built a collaborative information system, Garnet, which has several collaborative tools including the functionality of shared graphical information represented by Scalable Vector Graphics (SVG) . This is an example of what we call shared export - we choose important representations supported by several applications. We then build a custom shared event browser for this representation. The shared event model for collaboration is particularly important for sharing with heterogeneous clients as it allows different customizations for different clients. SVG is natural for all 2D vector graphics as in dynamic presentation (curricula pages), scientific visualization and whiteboards. Collaborative SVG is important as it illustrates the possibilities of sharing documents supporting the W3C DOM with its powerful and general event structure.
Graphical Information Exporting
The Garnet system is a collaborative information system supporting synchronous and asynchronous collaborative functions built on Peer-to-Peer network concept . Garnet is supported by a router network GMS (or Garnet Message Service). Garnet Message Service is a reliable publish/subscribe messaging service based on message-oriented middleware model (MOM). GMS is implemented either using a system Narada  we built or the commercial JMS Java Message Service. We have found the publish-subscribe mechanism gives excellent performance, substantial flexibility and natural integration of synchronous and asynchronous collaboration. Garnet uses XML based events transported by this GMS system between the collaborative clients. In its simplest mode Garnet uses the shared display model of collaboration but as discussed this is limited in capability in heterogeneous environments. Hand-held devices are supported as shown in the figure by a "personal server" which subscribes to the collaborative events and uses an optimized protocol (HHMS, the hand held message service) to communicate with a PDA.
Using a tool we developed, which converts Windows Metafile (WMF) to SVG , users can export their slides generated by Microsoft's PowerPoint to SVG document and share it among the collaborating clients. We define SVG elements for low-resolution devices with Cascading Style Sheets (CSS) on the personal server. Display types of small wireless devices are various: from 16bits color with 320x320 resolution  to 1 bit gray scale with 160x160 resolution .
Collaborative SVG Event Processing
Garnet collaboration system provides the interactive framework for collaborative SVG export. As a basic function, Garnet supports collaborative annotation. Each event for the annotation is translated to SVG document and sent to other participants as a message object. The received message is parsed and rendered dynamically.
The SVG event processing is based on the document model. Each exported SVG document creates DOM tree, any additional item is added to the DOM tree with DOM interface, and rendered dynamically. Every event message encoded with XML syntax is delivered to other participants via GMS.
Our system supports annotations at general pixel positions which are then rendered at appropriate scaled position on each client. Other approaches only support anchoring to objects within the SVG document.
Web based collaboration systems support universal accessibility to the devices with available Web browsers. There are various Web-based collaboration systems including commercial products such as WebEx Communication's WebEx , Centra Software's Centra , and PlaceWare's PlaceWare . However, small wireless devices are limited with their hardware power and their Web browser is not fully functional for current advanced Web technology. University of Pittsburgh's Pebbles PDA project  is suggesting a model of collaboration between heterogeneous Personal Digital Assistants (PDA).
Several collaboration systems enhance their accessibility with XML and XML based markup languages. Jabber, Inc.'s Jabber  is an instant messaging and presence-enabled applications and service with XML-based communication. Annotea  from W3C is a Web-based shared annotation system including SVG annotation. Annotea describes and manipulates the annotation with RDF schema. The universal W3C DOM document representation of information provides a key to interoperability in a heterogeneous environment.
 J. Ferraiolo, ed., Scalable Vector Graphics (SVG) 1.0 Specification. August 2000. http://www.w3.org/TR/2000/CR-SVG-20000802/.
 G. C. Fox. Ubiquitous Access for Computer Science and Education. ERDC Technical report, May 2001, http://aspen.ucs.indiana.edu/collabtools/
 G. C. Fox. Architecture and Implementation of a Collaborative Computing and Education Portal. ERDC Technical report, May 2001 http://aspen.ucs.indiana.edu/collabtools/ .
 Sony, Inc. CLIE Personal Entertainment Organizer Specifications, http://www.sonystyle.com/micros/clie/760specifications/PEG-N760C.html
 Palm, Inc. Palm m500 Handheld Product Details, http://www.palm.com/products/palmm500/details.html
 WebEx Communication, Inc. WebEx. http://www.webex.com
 Centra Software, Inc. Centra. http://www.centra.com
 PlaceWare, Inc. PlaceWare. http://www.placeware.com
 B.A. Myers. The Pebbles Project: Using PCs and Hand-held Computers Together. Proceedings CHI 2000 Extended Abstracts, pp. 14-15, The Hague, The Netherlands, 1-6 April 2000.
 Jabber, Inc. Jabber. http://www.jabber.com
 J. Kahan, M. Koivunen, E. Prud'Hommeaux, and R. Swick. Annotea: An Open RDF Infrastructure for Shared Web Annotations. In Proc. of the WWW10 International Conference. Hong Kong, 2001.
 S. Pallickara and G. Fox, papers at http://aspen.ucs.indiana.edu/users/shrideep/mspaces/documents.htm
This is a snapshot of shared SVG browser between desktop and handheld wireless device.