Addictive links: Adaptive Navigation Support in College-Level Courses
Peter Brusilovsky. Index What is adaptive navigation support? History behind adaptive navigation...
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Transcript of Peter Brusilovsky. Index What is adaptive navigation support? History behind adaptive navigation...
Peter Brusilovsky
IndexWhat is adaptive navigation support?History behind adaptive navigation supportAdaptation technologies that provide
adaptive navigation supportAdaptation mechanisms for adaptive
navigation supportAdaptive navigation support beyond
hypermedia
What is Adaptive Navigation Support?Specific group of technologies that help the
user navigate through the hyperspace by adapting to his goals, preferences and knowledge
The motivation is toHelp the user achieve the goals fasterReduce navigation overheadIncrease user’s satisfaction with the system
Used in application areas ranging from e-commerce to e-learning and in virtual museums
History behind adaptive navigation supportResearch started in early 1990’s Problems related to inefficient navigation and the
problem of being lost in the hypermediaEarly navigation support technologies used manual
indexing and provided navigation support within a closed corpus of documents
The Web provided an attractive platform for adaptive hypermedia applications
Research got divided into two parts:Using the known adaptive hypermedia technologies in
the new web contextDeveloping new technologies and new mechanisms
Focus on exploring real world systems rather than lab level systems
Adaptation TechnologiesDirect guidanceLink OrderingLink HidingLink AnnotationLink Generation
Direct GuidanceSuggests the next best page for the user to visit
according to the user’s goal, knowledge or preference
Needs the user model to know the user’s goals, knowledge and preferences
Direct guidance can be presented to the user in two waysIf the link is already on the page, it can be
outlined or emphasized. Examples WebWatcher and Personal WebWatcher
System can create a dynamic “Next” link which is connected to the next best page
Direct GuidanceDirect guidance provides no support for
users who do not wish to follow the system’s suggestions
Popular in adaptive educational hypermedia systems
Link Ordering (Adaptive Sorting)Prioritize all the links of a page according to
some user valuable criteria from the user model
The closer to the top, the more relevant the link is
The links can be manually reordered by dragging
Manual link reordering is considered by the system as a means of relevance feedback and is used to update the user model.
Link OrderingCannot be used for contextual links or maps
(index page or table of contents) This technology makes the order of links
unstable (it may change each time the user enters the page)
Appropriate where all or some of the pages have an unstable set of links like adaptive news systems
Link HidingRestricts the navigation space by hiding, removing
or disabling links to irrelevant pagesProtects users from the complexity of the whole
hyperspace and reduces cognitive overloadBased on the separation of three features of a link,
the following variants of link hiding are possibleLink removal-removes the link as well as the anchorLink hiding- preserves the anchor but removes all
visual indications that it is a linkLink disabling-removes the functionality
Link HidingUsed is educational hypermedia systemsLink hiding is a unidirectional technologyHiding can distinguish between only two
states for related pages – relevant or non relevant
Link AnnotationAugment links with some visual cues to let
the user know more about the page behind the annotated link
Icon based annotations and mouseovers are the most popular techniques
Preserves a stable order with the linksAnnotation can distinguish up to six states for
related pages
Link GenerationNewest adaptive navigation support technologyCreates new, non-authored links on a pageThree kinds of link generation
Discovering new links and adding them permanently to the set of existing links
Generating links for similarity based navigation between items
Dynamic recommendation of links that are useful within the current context to the current user
Link Generation vs. Web RecommenderRecommender systems suggest a list of items
that are relevant to the user’s short or long terms needs
Navigation systems focus on helping users to find their way through hyperspace by adapting links on a page
Comparison of the technologiesDirect Guidance
Sorting Hiding Annotation
Generation
Contextual links
OK Disabling
OK
Non-contextual links
OK OK OK OK OK
Table of Contents
OK OK
Index OK OKHyperspace maps
OK OK OK
Adaptation Mechanisms for Adaptive Navigation SupportSimple Adaptation MechanismsContent-Based MechanismsSocial MechanismsIndexing-Based Mechanisms
Simple Adaptation MechanismsDo not require advanced adaptation algorithmsHistory-Based Mechanisms
Count how many times each node in the hyperspace has been visited and attempt to represent this information visually
Trigger-Based MechanismsState of a link is connected with an event Once the event happens, the link appearance changesUsed by learning management systems
Progress-Based MechanismsTracks the user visit to a page on a deeper level like
time spent reading a page or amount of page exploration
Content-Based MechanismsMake a decision whether to suggest the user
a path to a specific page by analyzing page content
If the links is followed, the user profile is updated accordingly
Syskill & Webert
ScentTrails
Social MechanismsBased on the idea of social navigationOffered in two forms
Direct-direct interaction of users with each other in information space For direct social navigation, annotate links to pages that
are currently visited by other users with special iconsIndirect-traces the activities of the community of
users History enriched environments – footprint based
approach Collaborative filtering systems
CourseAgent system
Indexing-Based MechanismsUse manually-produced concept-level
document representation and concept-overlay models
Content of each page is expressed in terms of external concept level models
The same external model is used for building an overlay user model and page indexing
The external model used is generally a concept level domain model
Classification of Indexing ApproachesCardinality
Single-concept indexing- each page is related to only one external model concept
Multi-concept indexing-each page can be related to many concepts
Navigation-is the link between concept and a page on a conceptual level or does it define a navigational path?
Expressive Power-amount of information associated with every link between a concept and a pageRoleWeight
Basic Approaches to IndexingConcept Based Hyperspace-used in systems that use single
concept indexing Simple concept based hyperspace
Used in systems that have exactly one page in every system Hyperspace is the exact replica of the external model Each concept of external model is represented exactly by one node
of the hyperspace Enhanced concept based hyperspace
Each concept has a corresponding hub page in the hyperspace Used in adaptive e-learning systems
Page Indexing Used in systems that use multi concept indexing Each hypermedia page is indexed with several external
model conceptsConcept based Navigation
Combination of the above two approaches
Adaptive Navigation Support for Virtual Environments
Text based virtual environmentsMUDsMOOs
Web Virtual Reality