Authoring of Adaptive Hypermedia

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Authoring of Adaptive Hypermedia

• Alexandra Cristea
• a.i.cristea_at_tue.nl
• http//wwwis.win.tue.nl/alex/

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Outline

• AH
• AH authoring
• LAOS Layered WWW AHS Authoring Model and their
  corresponding Algebraic Operators
• LAG Layers of Adaptive Granulation
• MOT My Online Teacher
• Demos

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Adapt to what?

• User ? user model (UM)
• Media ? presentation model (PM)

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What to adapt?
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Traditional Hypermedia
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Adaptation on Trad. Hypermedia
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Adaptation on Trad. Hypermedia
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Adaptation on Trad. Hypermedia
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New, dynamic view of AH
text
Bits pieces
link

• Generation
• only text
• only link
• text link

text
link
text
link
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AH authoring

• new research direction

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LAOS

• What is LAOS?
• Concept based adaptation
• LAOS components
• Why LAOS?
• LAOS authoring steps
• Future directions

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What is LAOS?
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What is LAOS ?

• a generalized model for generic adaptive
  hypermedia authoring
• based on the AHAM model
• based on concept maps
• http//wwwis.win.tue.nl/alex/HTML/Minerva/papers/
  WWW03-cristea-mooij.doc

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Why LAOS?
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General motivation for layer distributed
information

• Flexibility
• Expressivity (semantics also meta-data)
• Reusability
• Non-redundancy
• Cooperation
• Inter-operability
• Standardization

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LAOS components
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LAOS components

• domain model (DM),
• goal and constraints model (GM),
• user model (UM),
• adaptation model (AM) and
• presentation model (PM)

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LAOS motivation in detail

• Why domain model (DM) ?
• Why goal and constraints model (GM)?
• Why user model (UM)?
• Why adaptation model (AM)? and
• Why presentation model (PM)?

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LAOS motivation in detail

• Why domain model (DM) ?
• Because of historical AHS, ITS, AHAM
• Why goal and constraints model (GM)?
• Why user model (UM)?
• Why adaptation model (AM)? and
• Why presentation model (PM)?

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LAOS motivation in detail

• Why domain model (DM) ?
• Why goal and constraints model (GM)?
• Why user model (UM)?
• Because of historical ITS, AHS, AHAM
• Why adaptation model (AM)? and
• Why presentation model (PM)?

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LAOS motivation in detail

• Why domain model (DM) ?
• Why goal and constraints model (GM)?
• Why user model (UM)?
• Why adaptation model (AM)? and
• Because of AHAM see also LAG !!
• Why presentation model (PM)?

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LAOS motivation in detail

• Why domain model (DM) ?
• Why goal and constraints model (GM)?
• Why user model (UM)?
• Why adaptation model (AM)? and
• Why presentation model (PM)?
• Because of Kuypers, AHAM

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LAOS motivation in detail

• Why domain model (DM) ?
• Why goal and constraints model (GM)?
• Because of book metaphor
• Why user model (UM)?
• Why adaptation model (AM)? and
• Why presentation model (PM)?

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GM book metaphor why?

• Domain model
• equivalent to skip the presentation and just tell
  the user to read the book.
• search space too big
• Not only one purposeful orientation

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GM motivation

• intermediate authoring step,
• goal constraints related
• goals focused presentation
• specific end-state
• constraints limit search space
• DM filter

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DM
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GM
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Authoring steps in LAOS

• STEP 1 write domain concepts concept hierarchy
  attributes (contents) other domain relations
• STEP 2 add content related adaptive features
  regarding GM (design alternatives AND, OR,
  weights, etc.)
• STEP 3 add UM related features (simplest way,
  tables, with attribute-value pairs for
  user-related entities (AHAM) UM can be
  represented as a concept map)
• STEP 4 decide among adaptation strategies, write
  in adaptation language medium-level adaptation
  rules or give the complete set of low level rules
  (such as condition-action (CA) or IF-THEN rules).
• STEP 5 define format (presentation
  means-related define chapters)

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LAOS components definitions
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Domain concept model

• Definition 1. An AHS domain concept map CM is
  determined by the tuple ltC,Lgt,
• where C set of concepts,
• L set of links (CM ?CM, set of all concept maps
  of the AHS).
• Definition 2. A domain concept c?C is defined by
  ltAc,Ccgt
• where Ac?? set of attrs and Cc set of
  sub-concepts.
• Definition 3. Amin is the minimal set of
  (standard) attributes required for each concept
  to have (Ac?Amin).
• for sufficient meta-data
• if Amin ? ?? required standard attributes.

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Domain concept model cont.

• Definition 4. A domain concept c?C is a composite
  domain concept if Cc??.
• Definition 5. A concept c?C is an atomic domain
  concept if Cc?.
• Definition 6. A domain link l?L is a tuple ltci,
  cj, nl, wlgt with ci?Ci, cj?Cj (ci??,
  cj??) start and end sets of concepts,
  respectively, nl a name or label of the link and
  wl a weight of the link.

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Domain concept model cont.

• Definition 7. A domain attribute a?Ac is a tuple
  ltvar,valgt,
• where var name of attribute (variable / type)
• val value (contents) of attribute.
• Constraints on the model
• Definition 8. ? concept c must be involved at
  least in one link l. This special relation is
  called hierarchical link (link to father
  concept). Exception root concept.

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Algebraic operators respective operations over
the model

• constructors
• create, edit
• destructors
• delete
• visualization or extractors
• list, view, check
• compositors
• repeat

• Effects
• restructuring (constructors, destructors and any
  compositors using at least one operator belonging
  to the previous categories) or
• structure neutral (visualization and any
  compositors applied to visualization alone)

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1 We assume here that val is defined
analogously for CM, c, l.
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Goal and constraints model

• Definition 9. A constraint concept c?C in GM is
  defined by the tuple lt Ac,Ccgt where Ac
  (card(Amin)2) set of attributes Cc set of
  sub-concepts.
• Definition 10. A constraint link l?L in GM is a
  tuple
• ltc1, c2, nl, wlgt with c1?C, c2?CM.C sets
  of start end concepts, nl a name representing
  the type (i.e., hierarchical AND/OR connections)
  of the link wl a weight of the link.

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Example 1 flexibility index between concept C1
and rest of concepts in C for automatic linking
in the DM or GM
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Example 2 flexibility degree for selecting
attributes from DM concept C1 for GM, considering
the order
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Future developments LAOS
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Future developments LAOS

• Operators for each layer (partially done)
• Automatic transformations between layers for
  authoring simplification (partially done)
• Automatic concept linking (partially done)
• Verification work of the different layers

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LAOS summary

• we introduced a five level AHS authoring model
  with a clear cut separation of the processing
  levels
• 1. the domain model (DM),
• 2. the goal and constraint model (GM),
• 3. the user model (UM),
• 4. the adaptation model (AM) - more LAG
  following
• 5. the presentation model (PM).

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Overview LAG

• What is LAG
• LAG components
• Why LAG?
• New adaptation rules
• Adaptation strategies

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What is LAG?
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What is LAG ?

• a generalized adaptation model for generic
  adaptive hypermedia authoring
• First paper http//wwwis.win.tue.nl/alex/Confere
  nces/02/AH02/calvi-cristea-final-w-header-ah2002.p
  df
• Second (referring) paper http//wwwis.win.tue.nl/
  alex/Conferences/02/ELEARN02/Cristea-Adaptation-A
  daptability.pdf
• Third paper http//wwwis.win.tue.nl/alex/HTML/Mi
  nerva/papers/UM03-cristea-calvi-accepted.doc

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LAG components
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LAG components

• Direct adaptation Techniques
• Adaptation Language
• Adaptation Strategies

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Adaptation granularity

• lowest level direct adaptation techniques
• adaptive navigation support adaptive
  presentation (Brusilovsky 1996), implem. AHA!
  expressed in AHAM syntax
• techniques usually based on threshold
  computations of variable-value pairs.
• medium level goal / domain-oriented
  adaptation techniques
• based on a higher level language that embraces
  primitive low level adaptation techniques
  (wrapper)
• new techniques adaptation language (Calvi
  Cristea 2002),
• high level adaptation strategies
• wrapping layers above
• goal-oriented

Adaptation Assembly language
Adaptation Programming language
Adaptation Function calls
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Why LAG?
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Motivation LAG

• Authoring with different complexity degrees
  (beginner authors vs. advanced)
• Reuse at each level
• Better semantics
• standardization

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New adaptation rules proposed(Adaptation
Language)
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Adaptation Programming language

• level rule
• IF ENOUGH(ltPREREQUISITESgt) THENltACTIONgt
• temporal rule
• WHILE ltCONDITIONgt DO ltACTIONgt
• repetition rule
• FOR lti1..ngt DO ltACTIONgt
• interruption command
• BREAK ltACTIONgt
• generalization command
• GENERALIZE (COND, COND1, , CONDn)
• specialization command
• SPECIALIZE (COND, COND1, , CONDn)

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A level rule

• IF ENOUGH(ltPREREQUISITESgt) THENltACTIONgt
• ENOUGH fct. of no. quality of prerequisites
  true if, e.g., a given no. of prerequisites from
  a set is fulfilled
• Ex PREREQUISITES time_spent ACTION go to
  next level
• Rule becomes
• IF ENOUGH (time_spent on crt. level) THEN go to
  next level
• Where ENOUGH is defined, e.g., as follows
• ENOUGH (time) 30 time units
• time (advanced topic) 10 (time units per
  topic)
• ENOUGH (medium topic) 5 (time units per
  topic)
• ENOUGH (beginner topic) 2 (time units per
  topic)

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A temporal rule

• action repeated as long as 1-more cond.s hold
• WHILE ltCONDITIONgt DO ltACTIONgt
• According to CM paradigm, concepts ? canned but
  assembled depending on UM their attr.s ( more
  than mere addition/deletion of links)
• E.g, a warning is repeated that user search
  direction is wrong. Another cond. can trigger a
  service denial response if a threshold is passed.

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A repetition rule

• a certain (simple / composed) action repeated for
  a no. of times predefined by author
• FOR lti1..ngt DO ltACTIONgt
• describes the time this action has to last before
  reader can move on.

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An interruption command

• user action is interrupted s/he is forced to
  undertake a different one
• BREAK ltACTIONgt
• represents an exacerbation of traditional
  behavior of AHS user is punished if she
  doesnt stick to learning pathways provided by
  system.

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A generalization command

• new concept reader has reached is compared w.
  more general ones it refers to. As a result, the
  reader is pointed to related concept(s)
• GENERALIZE (COND, COND1, , CONDn)

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A specialization command

• if concept is general, system deductively points
  reader to more specific instantiations
• SPECIALIZE (COND, COND1, , CONDn)
• E.g, if student reads about Model Reader in a
  course on postmodern literature, she can be
  pointed to an extract from Calvinos novel Se
  una notte, where this notion is exemplified.

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Other commands

• comparison (concept analogy search)
• difference
• both instances of generalization
• duration a rule related to repetition
• lyrical use of repetitions in hyperfiction has
  given rise to a particular design pattern

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Adaptation Strategies
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Adaptive strategies for cognitive styles
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Convergers are abstract and active like to feel
in control start with course for intermediates
at medium adaptivity level, repeat for a number
of times evaluate state of learner and start
increasing difficulty decreasing adaptivity
level if resultgood evaluate state of learner
and start decreasing level if resultbad
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converger (abstract, active)

• 1. Adaptation Strategy
• converger() generate adaptive presentation with
  (obviously) increasing difficulty
• 2. Adaptation Language (ENOUGH shows here that
  the result is above an average result)
• AdaptLevel 5 NAskUser() this is to let user
  feel and be in control levels (1min to
  10max)
• FOR ltI1..Ngt DO
• SPECIALIZE (ENOUGH(Result)) IF
  (AdaptLevelgt1) AdaptLevel--
• GENERALIZE (NOT(ENOUGH(Result))) IF
  (AdaptLevellt5) AdaptLevel
• Note that adaptation level is not allowed to
  increase too much
• 3. Direct Adaptation Techniques (the average can
  be implemented but takes more space)
• DiffLevel 3 AdaptLevel 5 note that here
  there is no predefined number of repetitions
• IF ltACTIONgt THEN Note that above we dont need
  the action of the user for triggering
• IF (Result1 Result2)/2gt5 AND DiffLevellt10
  THEN Note that enough and specialize
• DiffLevel IF (AdaptLevelgt1)
  AdaptLevel-- must be redefined each time
• IF (Result1 Result2)/2lt5 AND DiffLevelgt1
  THEN DiffLevel-- IF (AdaptLevellt5)
  AdaptLevel

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MOT Demo?
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RDF schema of MOT DM, GM
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RDF instance of MOT (DM,GM)
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On-line sites

• On-line download site
• http//wwwis.win.tue.nl/acristea/MOT/
• On-line trial sites
• http//e-learning.dsp.pub.ro/mot/
• http//e-learning.dsp.pub.ro/motadapt/