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Hypertext: Are we still not there yet? a hypertext unkeynote Prof. dr. Paul De Bra Eindhoven University of Technology The program states that this is a ... – PowerPoint PPT presentation

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Title: Hypertext: Are we still not there yet? a hypertext


1
HypertextAre we still not there yet?a
hypertext unkeynote
  • Prof. dr. Paul De Bra
  • Eindhoven University of Technology

2
Hypertext, are we still not there yet?
  • At HT98 we asked Are we here yet?
  • What was the answer, and why?
  • if yes then stop HT else continue HT
  • What was the answer really (each year), and why?
  • if yes then start making hypertext
    ubiquitous else continue to further develop
    hypertext
  • In fact we kept saying No until HT2006
  • Once we said Yes HT started doing well (again)

3
Lets step back into history
  • Vannevar Bush inventor of hypertext?As We May
    Think (Atlantic Monthly, 1945)But what did he
    really suggest
  • The human mind operates by association.With
    one item in its grasp, it snaps instantly to the
    next that is suggested by the association of
    thoughts, in accordance with some intricate web
    of trails carried by the cells of the brain. It
    has other characteristics, of course trails that
    are not frequently followed are prone to fade,
    items are not fully permanent, memory is
    transitory.
  • Selection by association, rather than indexing,
    may yet be mechanized. it should be possible to
    beat the mind decisively in regard to the
    permanence and clarity of the items resurrected
    from storage.
  • www.theatlantic.com/magazine/archive/1969/12/as-we
    -may-think/3881/

4
Lets step back into history
  • What did Bush really suggest (cont.)
  • If affords an immediate step, however, to
    associative indexing, the basic idea of which is
    a provision whereby any item may be caused at
    will to select immediately and automatically
    another. This is the essential feature of the
    memex. The process of tying two items together is
    the important thing.
  • he runs through an encyclopedia, finds an
    interesting but sketchy article, leaves it
    projected. Next, in a history, he finds another
    pertinent item, and ties the two together. Thus
    he goes, building a trail of many items.
    Occasionally, he inserts a comment of his own,
    either linking it into the main trail or joining
    it by a side trail to a particular item
  • There is a new profession of trail blazers, those
    who find delight in the task of establishing
    useful trails through the enormous mass of the
    common record.

5
If Bush did not invent hypertext, who did?
  • clue 1 who wrote

6
If Bush did not invent hypertext, who did?
  • clue 2 who wrote

7
What is hypertext according to Ted Nelson?
8
Some Basic Hypertext Ideas
  • Hypertext connects all texts
  • Xanadu magic place of literary memory
  • Copying (even quoting) is evil why quote when
    you can show the original in-line?
  • cross-reference links are a referral to
    information elsewhere (following the link takes
    you elsewhere)
  • transclusions look like quotes but the original
    source is shown in-line its not a copy(note
    transclusion requires fine-grained addressing)
  • (to avoid broken links) you can never really
    delete anything you can only create new versions

9
Quick look at hypertext between 1960 and 1990
  • Working hypertext
  • Hypertext Editing System (1967), FRESS (1968)
  • NLS, the oN-Line System (1968), successor of the
    Augment project to augment the human mind
  • ZOG, first hypertext system with real
    application (1972 - 1982), used on the USS Carl
    Vinson
  • Performance through simplicity
  • KMS let you navigate quickly (hoping to reduce
    disorientation)
  • Cards
  • Nodes became cards in NoteCards (over 50
    types), later also in HyperCard (with programmed
    behavior)

10
Quick look at hypertext between 1960 and 1990
  • More and more functionality Intermedia
  • linking protocol to integrate different
    applications (for different media) this is like
    mash-ups
  • bidirectional links
  • links not hardwired to nodes, users can create
    their own web of links
  • Complete programmability HyperCard
  • link is just the goto statement of a
    programming language link anchors are
    independent of content
  • Link databases Hyperties
  • database of anchor-destination pairs
  • open hypermedia takes this idea further

11
Some illustrations
  • Intermedia web view
  • Intermedia create link(and other options)
  • HyperCard stacks

12
So hypertext systems became sophisticated!
  • All functionality of all systems represented in a
    model the Dexter Model (NIST Workshop, 1990)

13
Essential Dexter elements/properties
  • Components atom, link, composite component
  • atom is an atomic fragment
  • composite
  • a page is a composite element (consists of atoms)
  • an abstract composite component consists of other
    (smaller) components, either abstract or atoms(a
    composite with atoms is a page)
  • link sequence of two or more endpoints
    (unidirectional, bidirectional or even
    undirected)
  • Page selector when a link destination is
    abstract (composite) a page must be selected to
    be displayed
  • Page constructor after a page is selected the
    presentation must be constructed from the atoms

14
And then
15
The (early) Web
  • Tim Berners Lee (1989/1990) the Web as an aid
    for physicists for sharing documents
  • Marc Andreessen (1992) the Mosaic browser made
    the Web read-only
  • Key properties/limitations in the basic Web
  • uni-directional links between single nodes
  • links are not objects (have no properties of
    their own)
  • links are hardwired to their source anchor
  • only pre-authored link destinations are possible
  • monolithic browser
  • static content, limited dynamic content through
    CGI
  • links can break
  • no transclusion of text, only of images

16
So why was this primitive Web successful?
  • Simplicity
  • Especially publishing was very simple (HTML)
  • Availability
  • Everyone could get it and use it (and it was
    free)
  • Timeliness
  • The Web became available when Unix and X-Windows
    became popular, and when Internet became
    available
  • (Pure) Client-Server Architecture
  • This was fitting for the typical computing
    infrastructure with powerful file servers and
    less powerful workstations

17
Are we there yet? Take two ?
  • 1990 (start of the Web) threw us back to pre-1960
  • Two approaches to recover
  • This is bad, lets build a better alternative.
  • This is bad, lets make it better.
  • Since 1990 we are working on the second
    approachIf you cant beat them, join them.
  • Are we there yet? Have we integrated
    everything from 1960-1990 into the Web yet?
  • but also Are we using everything from 1960-1990
    on the Web yet?

18
So how do we get there?
  • Take the Web browser and server for
    granted!Build extensions into this architecture
  • browser plugins
  • browser applets
  • proxy services
  • server side scripts
  • servlets
  • database back-end
  • extend user interface,
  • browser offers network int.
  • change content on the fly
  • select or compute content
  • better storage

19
Example GRAPPLE / GALE
  • Overall GRAPPLE Infrastructure

20
GRAPPLE Adaptive Learning Environment
21
Things that make GALE into real hypertext
  • Domain Model (DM) with concepts and relations
  • for each concept there may be several resources
  • concepts and resources identified by URI
  • User Model (UM) with for each concept certain
    attributes (values)
  • Links always refer to concepts
  • page selection concept access involves
    (recursive) resource selection
  • page construction page may contain
  • conditionally included fragments
  • conditionally included objects (object
    transclusion)

22
Things that make GALE able to get there
  • Spring configuration lets you change most things
  • Processing is done by a pipeline of
    processors(LayoutProc., Loadproc., XMLProcessor,
    )
  • XML adaptation is done by modules (one per tag)
  • ltifgt for conditional fragments
  • ltobjectgt for transclusion of objects (concepts)
  • ltagt for adaptive links
  • ltforgt for generating a list of elements
  • ltvariablegt for selecting DM or UM info
  • ltviewgt for arbitrary generated views over DM
  • lttestgt for multiple choice tests (specific for
    e-learning)

23
Example application Milkyway
24
Are we there yet?
  • Yes (for the most part) we are there. So
  • Time to look into hypertext applications more
    closely
  • Careful not to confuse hypertext with web
    application
  • Time to look for new hypertext concepts that go
    beyond the state of the art from
    1990.Visionaries have already done so
  • Semantic Web (web of data, leading to web of
    things)
  • Multi-dimensional structures/browsing ZigZag
  • Mobile applications, combining on-line
    location-aware communication and information
    sources
  • what you will come up with!

25
See you all
  • at HT2011!
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