ECDL 2002 Employing Smart Browsers to Support Flexible Information Presentation in Petri net-based Digital Libraries Unmil P. Karadkar, Richard Furuta Texas A&M University, USA Jin-Cheon Na Nanyang 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

ECDL 2002 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

ECDL 2002 Scenario of Use (Contd.) Acccess from text and image browsers

ECDL 2002 Scenario of Use (Contd.) Getting help from text and image browsers

ECDL 2002 Scenario of Use (Contd.) Access from Web browsers

ECDL 2002 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, Center for the Study of Digital Libraries Department of Computer Science Texas A&M University Jin-Cheon Na Nanyang Technological University, Singapore