B.N STONEY 11

TOWARDS THE ADAPTIVE SEMANTIC WEB(Peter Dolog et al)

BASHIR NAGIB STONEY

JULY 2ND 2013

02. July.2013

B.N STONEY 22

Outline• Background: Adaptive Hypermedia Systems• Concept

When are Adaptations Useful??Application AreasAdaptation TechniquesAdaptive Vs Adaptable Systems• What is Personalization? Does one size fit all? How does Personalization Work? Recommender systems• Logic-based Definition of Adaptive Educational

Hypermedia Systems • Simple: A Simple Adaptive Educational Hypermedia

System• Semantic Web Triples

02. July.2013

B.N STONEY 33

Definition:• Adaptive Hypermedia Systems

(P. Brusilovsky: Methods and Techniques of Adaptive Hypermedia. User Modeling and User-Adapted Interaction 6 (2-3), 1996)

Different voices on adaptive hypermedia• The ambition of adaptivity is that not only `everyone should

be computer literate', but also that 'computers should be user literate' (Browne, 1990)

“By adaptive hypermedia systems we mean all hypertext and hypermedia systems which reflect some features of the user in the user model and apply this model to adapt various visible aspects of the system to the user."

02. July.2013

B.N STONEY 402. July.2013

HYPERMEDIA SYSTEM

ADAPTATION COMPONENT

USER MODEL

Data about user Request of user Adaptation results

update Get current knowledge

Process flow of and of Adaptive Hypermedia System

B.N STONEY 5

Adaptive Hyperwhat??

02. July.2013

• In 1945, Vanevar Bush envisioned a machine, the memex. Byconsulting several sources consecutively, a user builds anassociative trail of related documents, which can be labeled andannotated with notes and comments.consulting several sources consecutively, a user builds anassociative trail of related documents, which can be labeled andannotated with notes and comments.

• Similar to this idea, hypertext is a collection of documents that isconnected by (associative) links.• The World Wide Web is the most common form of hypertext.

B.N STONEY 6

When are Adaptations Useful?• when the hypertext is sufficiently largeneed for guidance, recommendations and information filtering• and is used by people with different goals and backgroundsneed to adapt to resulting differences in needs and user context Adaptive hypermedia are an answer to the problem of disorientation,

commonly known as “Lost in Hyperspace“The root of disorientation is the additional cognitive overhead needed

for users to:• identify their current position in a hyperdocument;• reconstruct the way that led to this position;• distinguish among different options for moving on from this position.

02. July.2013

B.N STONEY 7

Lost in Hyperspace • When users fail to keep track of their navigation through a document, they

might arrive at a particular page and forget what was to be done there, they might neglect to return from interesting side-tracks or they might fail to find some pages that contain relevant information.

Compare this with books:• in a novel you can easily track how much you have already read and

how much there is still to read• books provide easy-to-remember cues for remembering: page

number, position within the pageEveryday examples on the Web:• Where can I find whether my train is on-time?• What was the name of that book I found on Amazon?• Which query did I use to find this list of hotels that I did not save?

02. July.2013

B.N STONEY 8

Application Areas• Educational hypermedia. Traditionally, the most popular application

area. User needs are well-identified: acquiring knowledge on a certain topics. User characteristics (e.g. knowledge level, interest) are well-researched.

• Online information systems. Nowadays we would simply refer to them as Web sites. A popular adaptation technique is collaborative filtering and automated recommendations of products or other items.

• E-commerce. Product recommendations and personalized offers are particularly important in the field of e-commerce

• Web information retrieval. The filtering, sorting, categorizing or annotating of search results based on the users' search history.

02. July.2013

B.N STONEY 9

Adaptation Techniques There are two main categories of adaptation techniques:

adaptive presentation and adaptive navigation support.• Nodes:- Content-level adaptation, adaptive presentation

techniquesWhich means to select\modify\rearrange the content of the

documents• Edges:- Navigational-level adaption, adaptive navigation

supportWhich means to select appropriate hypertext links, delete

links,or generate new links.

02. July.2013

B.N STONEY 1002. July.2013

Hypertext

B.N STONEY 11

Adaptive Vs Adaptable Systems

02. July.2013

ttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttt

Adaptable means that users can adapt system behavior themselves e.g iGoogle personalized start page

B.N STONEY 1202. July.2013

Adaptive means that the system adapts its own behavior on the users behalf e.g. Amazon recommendations

B.N STONEY 13

What’s Personalization??

02. July.2013

Personalization is a designers' approach to achieve harmony between users, tasks, environmentsand the system (Benyon, 1993)

Personalization is an overrated concept. Rather than investing time and energy on trying to predictindividual users' needs it would be better to enhance the overall site design. (Nielsen, 1998)

B.N STONEY 14

Does one Size fit all??In a library, a person looks for some books on China. What

will thelibrarian recommend?• Is the person a small child who saw a TV show about Chinaand wants to learn about this exotic country?• Or a high school student working on a paper?• Perhaps a prospective tourist?• A scholar interested in Eastern philosophy?• Someone who can read Chinese?

Elaine Rich: User Modeling via Stereotypes. Cognitive Science 3, 329-354 (1979)02. July.2013

B.N STONEY 15

Most likely the librarian will make an educated guess, based on theperson's appearance :- age, style of clothing, accent, choice of words, ...

02. July.2013

B.N STONEY 16

This initial guess might be confirmed or refuted by observations.

• It is assumed that a European cannot read Chinese, unlesssaid otherwise• Children are generally not (yet) interested in Easternphilosophy, but there are exceptions . . ………….• The educated guess, a stereotype can be refined with

follow-upquestions.Persons expect a personalized advice, even though the

librariandoes not know them. 02. July.2013

B.N STONEY 17

How does Personalization Work?In a nutshell, a personalized system tries to understand the

userusing• information that he or she provides• activities that a user carries outAnd tries to guess what you currently want to do, by

comparing• you with people that are similar to you• things that you own or like with similar things

02. July.2013

B.N STONEY 18

Recommender Systems

Items may be: movies, tv programs, music, books, news, images,

web pages, scientific literature, . . .

02. July.2013

Recommender systems work from a specific type of information filtering system technique that attempts to recommend items that are likely to be of interest to the user.

B.N STONEY 19

• Content-based systems:- examine properties of the items recommended. For instance, if a Netflix user has watched many cowboy movies, then recommend a movie classified in the database as having the “cowboy” genre.

• Collaborative filtering systems recommend items based on similarity measures between users and/or items. The items recommended to a user are those preferred by similar users.

02. July.2013

B.N STONEY 20

A logic-based definition of Adaptive Educational Hypermedia Systems(AEHS)E-learning has been an important application area of

adaptive hypermedia research.• clearly defined user goals (learning outcomes)• established ways to test whether the goals have been met

(e.g. tests)• known individual differences between learners (e.g.

knowledge, learning style, learning goals)

02. July.2013

B.N STONEY 21

Components of a AHS An adaptive educational hypermedia system (AEHS) is a

Quadruple ( DOCS, UM, OBS, AC ) DOCS: Document Space: A finite set of first order logic (FOL) sentences withconstant symbols for describing documents (and knowledge concepts), andpredicates for defining relations between these (and other) constant symbols.UM: User Model: A finite set of FOL sentences with constant symbols fordescribing individual users (user groups), and user characteristics, as wellas predicates and formulas for expressing whether a characteristic applies toa user.OBS: Observations: A finite set of FOL sentences with constant symbols fordescribing observations, and predicates for relating users, documents / con-cepts, and observations.AC: Adaptation Component: A finite set of FOL sentences with formulas fordescribing adaptive functionality.

02. July.2013

B.N STONEY 22

“Simple”: A Simple Adaptive Educational Hypermedia SystemThis adaptive educational hypermedia system can annotate

the links of the hypertext according to the actual knowledge state of the user.

Simple: Document Space A set of n constants (n corresponds to the number of documents in the document space) which represent the documents:

D1, D2, : : :, Dn.A finite set of predicates stating the documents that need to

be studied before a document can be learned, e.g. Dj is a prerequisite for Di:

preq(Di, Dj) for certain Di≠Dj .Simple: User Model A set of m axioms, one for each

individual user:U1, U2, : : :, Um. 02. July.2013

B.N STONEY 23

Simple: Observations One constant for the observation whether a document has been visited:

Visited.And a set of predicatesobs(Dj , Ui, Visited) for certain Dj , Ui.Simple: Adaptation Component One constant for

describing the values of the adaptive functionality “learning state":

Recommended for reading,and two constants representing values of the adaptive

functionality:Green_Icon, Red_Icon.Rules for describing the learning state of a document

02. July.2013

)__Re,,(_)),,(),((

learningforcommendedUiDjstatelearningVisitedUiDkobsDkDjDkpreq

DjUi

B.N STONEY 24

TRIPLES

02. July.2013

The Semantic Web is an extension of the current web in whichinformation is given a well-defined meaning, better enablingcomputers and people to work in cooperation.

Tim Berners Lee

B.N STONEY 25

TRIPLE Overview• Triple is rule language for the Semantic Web.• A core building block of RDF is triples: subject -predicate - object.

• The RDF Data Model“Peter is interested in Sweden”subject: http://www.peter.de/foaf.rdf#me;predicate: foaf:interest;object: http://en.wikipedia.org/wiki/Sweden;

02. July.2013

B.N STONEY 2602. July.2013

B.N STONEY 27

Conclusions• An Approach to Personalization on the Semantic Web based

on reasoning was described.• Adaptive Hypermedia is an Alternative to the traditional

“one-size-fits-all” static approach of hypermedia systems• Adaptive Web vision is to provide users with optimized

access to distributed electronic information on the Web according to particular needs of individual users or group of users.

02. July.2013

B.N STONEY 28

SEMANTIC WEB TECHNOLOGIES FOR THE ADAPTIVE WEBPeter Dolog and Wolfgang Nejdl

Outline• Hypertext• Adaptive Web Systems• Ontogolies• Reasoning Techniques• eLearning Domain

02. July.2013

B.N STONEY 29

Definition

The Links are provided either explicitly, encoded by authors of the pages, or they are generated automatically, for example based on the results of the query.

The Adaptive Web Systems extend the adaptive navigation and presentation techniques from closed corpus adaptive hypermedia to the open corpus information resources available on the Web.

02. July.2013

Hypertext interlinks related pieces of information(pages) and allows the user to browse through the information space

B.N STONEY 30

Ontologies: represent shared and agreed upon conceptual models

in a domain, which describe the main concepts of the domain and their relationships.

Ontologies can thus serve as reference models for generating links in this domain, and represent hypertext, content and user information.

Reasoning techniques can then work on metadata based on these ontologies, and generate links based on content, user context and user background.

02. July.2013

B.N STONEY 31

Hypertext and Links

02. July.2013

Links in Conceptual open hypermedia are usually described as associations between the source and target information fragments

Figure showing the adaptive context of a learning resourcein a course.

B.N STONEY 32

The Link is annotated by a traffic light metaphor to inform the user which of the resources are ready for him to use according to his background

• The Green Symbol:- means that a link is recommended• Red:- a link is not recommended • Yellow:- User has to acquire some prerequisite background

needed to access the resource.

02. July.2013

B.N STONEY 3302. July.2013

A prototype for search user interface.

B.N STONEY 34

Reasoning on the Semantic Web• Several query and reasoning languages have been introduced to

query for, and reasonon, metadata on the semantic web such as QEL or SPARQL.

• The semanticsof the languages are often based on Datalog, as used in the Edutella Query Language(QEL) and extended rule and logic programming languages.

• QEL offers a full range of predicates in addition to equality, general Datalog rules,and outer join. An example for a simple QEL query over resources is the

following:s(X, <dc:title>, Y),s(X, <dc:subject>, S),qel:equals(S, <java:OO_Class>).

02. July.2013

B.N STONEY 35

• The query tries to find resources where dc:subject equals java:OO Class. The

prefixes qel:, dc:, and java: are abbreviations for URIs of the schemas used. Variable X will be bound to URIs of resources, variable Y will be bound to titles of the resources, and variable S will be bound to subjects of the resources.

• A rule language especially designed for querying and transforming RDF models isTRIPLE . Rules defined in TRIPLE can reason about RDF-annotated information resources, translation tools from RDF to TRIPLE and vice versa are provided.

02. July.2013

B.N STONEY 36Sergej Zerr 36

THANK YOU!!!!!!!

02. July.2013