1. LAOS: Layered WWW AHS Authoring Model and their corresponding Algebraic Operators
Alexandra I. Cristea
UNESCO workshop “Personalization in Education” Feb’04

2. Overview: LAOS What is LAOS Concept based adaptation LAOS components
Why LAOS?
LAOS authoring steps
Future developments

3. What is LAOS?

4. What is LAOS ?
a generalized model for generic adaptive hypermedia authoring
based on the AHAM model
based on concept maps

5. Concept-based adaptation

6. Typical adaptivity Most AS = rule-based, i.e.:
Adaptation : conditional rules:
IF <PREREQUISITE> THEN <ACTION>

7. LAOS components

8. LAOS components domain model (DM), goal and constraints model (GM),
user model (UM),
adaptation model (AM) and
presentation model (PM)

10. Why LAOS?

11. General motivation for layer distributed information
Flexibility
Expressivity (semantics: also meta-data)
Reusability
Cooperation
Standardization

12. 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)?

13. 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)?

14. 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)?

15. 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)?

16. 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

17. 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)?

18. 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).

19. 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

20. DM

21. GM

22. 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

23. Authoring steps in LAOS
STEP 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.).

24. Testing at PUB In the testing we do LAOS LAG (see next presentation)
steps 1, 2
Partially 3
Step 4
LAG (see next presentation)
Step 6
Optionally 8

25. Future developments LAOS