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ECDL 2002
Employing Smart Browsers to Support Flexible Information Presentation
in Petri net-based Digital Libraries
Unmil P. Karadkar, Richard FurutaTexas A&M University, USA
Jin-Cheon NaNanyang Technological University, Singapore
ECDL 2002
Introduction
• For effective use in the real world, Digital Libraries must provide support for– diversity in access and use
• via various devices
• in different situations
• for different tasks
– enforcement of policies• user-specific, resource-specific, system-wide
• access, payment,
ECDL 2002
Introduction (contd.)
• Dynamic environment– actions of users affect others
• Adaptation of presentation– server side (WWW)
– client side (current caT implementation)
– coordinated between the server and clients
(future caT implementation)
• Support can be provided at various levels– as DL Application level (WWW)
– in DL document specification (Trellis)
ECDL 2002
Trellis
• Supports – specification of structure and browsing
semantics of hypertext documents using colored timed Petri nets
– specification of access control – time-based hypertext browsing
• Separates– content from structure– presentation from content
ECDL 2002
Examples of Petri nets
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context-aware Trellis (caT)
• Incorporates context-awareness in Trellis
• Provides for basic user modeling
• Structured tokens contain dynamic and environmentally changing data
• Transitions may contain conditional statements
ECDL 2002
Extending caT
• State of the net is stored at the server– multiple browsers on possibly multiple devices
can display the state– allows users to synchronously browse a
hypertext from multiple devices– user actions in one browser cause changes to
contents displayed in all browsers
• Places in nets point to abstract resource handles
ECDL 2002
Resource Realizer
• Allows authors of Trellis hypertexts to bind together resources – conceptually similar resources
– multiple representations of a resource (text, pdf, image, audio, video)
– otherwise interchangeable resources
• An abstract resource handle provides an interface to the resources that are bound together
• The Resource Realizer returns an instantiation of the resource upon request
ECDL 2002
Smart Browsers
• Browsers that are aware of – their capabilities (media types they can render)
– constraints imposed by the devices they run on (display space, resolution, network bandwidth)
• While browsing abstract resource handles are returned to browsers
• Browsers request the document format that they can best render
• Resource Realizer returns the best possible match with the requested resource type
ECDL 2002
Scenario of Use
• User accessing a bus information system for a large university campus
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Scenario of Use (Contd.)
• Acccess from text and image browsers
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Scenario of Use (Contd.)
• Getting help from text and image browsers
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Scenario of Use (Contd.)
• Access from Web browsers
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Coordinated Information Displays• Coordinated partial displays on multiple devices
– maximize the space for information display– provide a seamless interactive information space across
multiple devices– use of more than one senses– present information in the most appropriate format for
the given situation
• Server-side Browser Manager distributes display of information across devices
• Browser Coordinator invokes various browsers on a device
ECDL 2002
caT Architecture
ECDL 2002
Future Work
• Complete design and implementation of the Coordinated display system (Browser Manager and Browser Coordinators)
• Enhance interaction between browsers and the Resource Realizer to incorporate preferences, current task and situation of the user
• Explore possibilities for other resource bindings– versioning of resources
– competing services
ECDL 2002
Questions and Suggestions to
Unmil P. Karadkar, Richard Furuta {unmil, furuta}@csdl.tamu.edu
Center for the Study of Digital Libraries
Department of Computer ScienceTexas A&M University
Jin-Cheon Na
Nanyang Technological University, Singapore
