LAOS:Layered WWW AHS Authoring Model and
their corresponding Algebraic Operators
Alexandra I. CristeaUSI intensive course “Adaptive Systems” April-May 2003
Overview: LAOS
1. What is LAOS
2. Concept based adaptation
3. LAOS components
4. Why LAOS?
5. LAOS authoring steps
6. Future developments
What is LAOS?
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
Concept-based adaptation
Typical adaptivity
• Most AS = rule-based, i.e.:
• Adaptation : conditional rules:
IF <PREREQUISITE> THEN <ACTION>
Adaptive navigation & presentation
Adaptive navigation & presentation
Adaptive navigation & presentation
Adaptive navigation & presentation
Adaptive navigation & presentation
Adaptive navigation & presentation
Adaptive navigation & presentation
Adaptive navigation & presentation
LAOS components
LAOS components
• domain model (DM),
• goal and constraints model (GM),
• user model (UM),
• adaptation model (AM) and
• presentation model (PM)
Why LAOS?
General motivation for layer distributed information
• Flexibility
• Expressivity (semantics: also meta-data)
• Reusability
• Cooperation
• Standardization
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)?
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)?
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)?
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
• Why presentation model (PM)?
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
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)?
GM book metaphor
• generally speaking, when making a presentation, be it on the Web or not, we base this presentation on one or more references. Simplifying, a presentation is based on one or more books.
• With this in mind it is obvious why we cannot jump from the DM to the AM (or UM): it would be equivalent to skip the presentation and just tell the user to read the book.
• So, the search space is too big and there is a too high degree of generality (no purposeful orientation of the initial material - i.e., book).
GM motivation
• So, what we need is an intermediate authoring step that is goal and constraints related:
• goals to give a focused presentation, and • constraints to limit the space of the search . • Simplifying, we can consider
– the goal as being a specific end-state, and
– the constraint to be defined as a sub-layer of GM
Authoring steps in LAOSSTEP 1: write concepts + concept hierarchy
STEP 2: define concept attributes (main and extra attributes)
STEP 3: fill concept attributes (write contents)
STEP 4: add content related adaptive features regarding GM (design alternatives – AND, OR, weights, etc.)
STEP 5: 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 6: 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 7: define format (presentation means-related; define chapters)
STEP 8: add adaptive features regarding presentation means (define variable page lengths, variables for figure display, formats, synchronizations points , etc.).
Future developments LAOS
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