laos: layered www ahs authoring model and their corresponding algebraic operators alexandra i....

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