REFLECTIONS ON NOTECARDS: SEVEN ISSUES FOR THE NEXT GENERATION OF HYPERMEDIA FRANK G. HALASZ

1. REFLECTIONS ON NOTECARDS: SEVEN ISSUES FOR THE NEXT GENERATION OF HYPERMEDIA FRANK G. HALASZ

2. About NoteCards • Developed at Xerox PARC by Frank Halasz, Thomas Morgan and Randall Trigg • Workstation based Hypermedia System • Used for analyzing information, constructing models, formulating arguments, designing artifacts and processing ideas • System is a network of electronic notecards interconnected by typed links

3. Four Basic Constructs • Notecards electronic generalization of the 3 x 5 paper notecard displayed using standard Xerox Lisp windows several types like text-based cards, animation cards,etc. • Links typed, directional connection between a source card and a destination card

4. Four Basic Constructs • Browsers notecard containing the structural diagram of a network of notecards the diagrams in browsers are computed by system • Fileboxes specialized cards for managing large network of notecards by using an additional hierarchical category structure for storage and retrieval

5. 1st Generation Hypermedia Systems • NLS/Augment, FRESS, ZOG • Mainframe based • Focused primarily on text nodes • Little or no graphic capabilities • Supported medium to large teams of workers sharing a common network

6. 2nd Generation Hypermedia Systems • Began in early 1980s • Workstation based, research oriented systems • NoteCards, Neptune, Intermedia • Support graphics, animation nodes and fully formatted text nodes • Meant for single users or small work groups

7. Diversity in Hypermedia Systems • Scope size of information database and user population varies • Browsing Vs. Authoring Browsing-oriented System - well-developed tools for information presentation and exploratory browsing. Eg. Interactive museum exhibits Authoring-oriented System – well-developed tools for creation and modification of the network. Eg. Document authoring systems • Target Task Domain designed to support specific task. Eg. Neptune supports software engineering and hence focuses on versioning

8. NoteCards • Designed for small groups • Authoring System • General purpose hypermedia system • Originally designed for use in idea processing in research environment

9. Seven Issues for the next generation Hypermedia Systems Issue 1:Search & Query in Hypermedia Network • Hypermedia is navigational access • For effective access query/search facility must complement navigation • Three classes of navigational applications • NoteCards meant for small user groups • Display-oriented representation tasks. Network is centered around a single display • On-line interactive presentations • Navigational access difficult when network changes and structure becomes heterogeneous

10. Seven Issues for the next generation Hypermedia Systems Issue 1:Search & Query in Hypermedia Network (Contd..) • Browsers made more effective by applying techniques like fish-eye views and graph flyovers • Content search and Structure search mechanisms can be introduced • Example Query - all subnetworks containing two nodes connected by a supports link, where the destination node contains the word “hypertext.” • For implementing structure search, a query language to describe hypermedia structures and a search engine capable of satisfying the queries must be developed

11. Seven Issues for the next generation Hypermedia Systems Issue 2: Composites – Augmenting the Basic Node and Link Model • Hypermedia models lack composition mechanism • Browsers cannot understand and display compositions • Fileboxes fail to differentiate between reference relations and inclusion relations • Documents can be seen at only one level • Solution is to add composition as a primitive construct in the basic hypermedia model

12. Seven Issues for the next generation Hypermedia Systems Issue 3: Virtual Structures for Dealing with Changing Information • Hypermedia data model is static and fragmentary • Problem of “premature organization” • Relaxation of strict titling and filing requirements will help • Virtual structures can be defined – requires query mechanism • Virtual composite allows user to create nodes dynamically at access time from other nodes, links and composites in the network • Virtual links are also possible

13. Seven Issues for the next generation Hypermedia Systems Issue 4: Computation in (over) Hypermedia Networks • Hypermedia systems are passive storage and retrieval systems • Notecards can be augmented with active computational engines for particular applications • Future hypermedia systems should function more like knowledge-based AI systems • Merging concepts from frame-based systems and object-based systems • Choice between active and passive system is a trade off between efficiency and generality

14. Seven Issues for the next generation Hypermedia Systems Issue 5: Versioning • NoteCards does not have a versioning system • Versioning not required for authoring, argumentation and idea processing tasks • Crucial for software development applications • Neptune provides time-based linear version thread for individual nodes and links • PIE uses a layer mechanism • PIE provides a collaborative system

15. Seven Issues for the next generation Hypermedia Systems Issue 6: Support for Collaborative Work • Collaborative work involves creating annotations, maintaining multiple organizations of a single set of materials, and transferring messages between asynchronous users • Notecards is a single user system • The mechanics of simultaneous multi-user access to common network must be improved – hard locking techniques are inappropriate • Social interactions must be provided

16. Seven Issues for the next generation Hypermedia Systems Issue 7: Extensibility and Tailorability • Hypermedia systems are flexible and hence have broad applications • Generic nature – a boon and a bain • NoteCards – lack of strategy manual showing uses of the system in specific tasks • Extensibility – extend the system with new functionality • Tailorability – tailor the existing functionalities to better suit the application • Achieved in NoteCards by providing programmatic access to system’s functionalities