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

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)?



• Because of historical AHS, ITS, AHAM









• Because of historical ITS, AHS, AHAM








• Because of AHAM








• Because of Kuypers, AHAM




• Because of book metaphor




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

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

Documents

adaptation model

domain model

presentation model pm

aham model

generalized model

constraints model gm

user model um

aham slide