Adaptable and Adaptive Web Information

October 14, 2005 www.dcs.bbk.ac.uk/~gmagoulas/ 1

Adaptable and Adaptive Web Information

Systems

Lecture 1: Introduction

George [email protected]

School of Computer Science and Information Systems

Birkbeck College University of London


Contents

The Web, hypertext and hypermediaAims and objectives of the moduleCommon questions about Adaptive Web Systems Levels of adaptation and techniquesModelling human behaviourTopics covered in this moduleReading materials


The Web, hypertext, and hypermedia

Internet : vast collection of interconnected networks that all use the TCP/IP protocols



World Wide Web (WWW): system of Internet servers that support documents formatted in a markup language called HTML (HyperText Markup Language). This language supports linking a document to other documents, as well as linking to graphics, audio, and video files.

The Web is an information-sharing model that is built on top of the Internet. It uses the HTTP protocol to transmit data.

The Web is just one of the ways that information can be disseminated over the Internet. The Internet, not the Web, is also used for e-mail, which relies on SMTP and FTP.


The Web, hypertext, and hypermediaHypertext Transfer Protocol (HTTP) is the

set of rules for delivering Web pages over the InternetHTTP uses the client/server model

The client opens an HTTP session and sends a request to a serverThe server returns an HTTP response message which contains data.

After this, they forget about each other – this has very significant implications for Web application development.


The Web, hypertext, and hypermediaHypertext Markup Language (HTML)

markup language used to create documents on the Web today

HTML tags: Interpreted by Web browser and used by it to format the display of the text

HTML Links

Linear hyperlink structure

Hierarchical hyperlink structure


The Web, hypertext, and hypermediaHypertext is defined as “non-sequential writing – text that branches and allows choices to the reader, best read at an interactive screen”. [Nelson, 1960]

“The concept of hypertext is quite simple: Windows on a screen are associated with objects in a database, and links are provided between these objects, both graphically (as labelled tokens) and in the database (as pointers)”. [Conklin, 1987]


The Web, hypertext, and hypermediaHypermedia is represented as a network of nodes

connected by links.

A node is a unit that contains text and/or multimedia elements.A link is usually directed and connects two nodes: the source node and the destination node. It is associated with a specific part of the content of the source node, such as word, phrase or image. This part of the source node is called an anchor. This linking capability allows non-linear organisationof the text or multimedia content. The activity whereby the user accesses a node by following links is called navigation.


The Web, hypertext, and hypermediaHypermedia flexibility comes at a price:

The complexity of the system may increase: users may need more time to search for the information, and the dynamism and richness of the content may negatively affect users’ level of comprehension.In a number of activities, e.g. education, collaboration etc, despite the plethora of communication tools, users sometimes feel isolated or not supported enough.It is unlikely all people are equally able to performing their own content sequencing and navigation. Moreover, users are not always going to use the content in an effective way.



Previous knowledge of the application domain varies for different users, and indeed knowledge may grow differently through the interaction with the system. Users tend to get lost, especially when the information space is large and/or when they are novices. This can lead to disorientation experienced when users do not know where they are within hypertext documents and how to move towards the desired location, commonly known as “lost in hyperspace”.


The Web, , hypertext, and hypermedia

Users may fail to get an overview of how all the information fits together when browsing. In the absence of information that might help them formulate knowledge goals and find relevant information, users may stumble through the content in a disorganised and inefficient manner. Furthermore, if users are too accustomed to memorising and are faced with multiple explanations of the same knowledge, they may attempt to memorise them all. This is one of the aspects of a problem known as “information overload” which is usually experienced by users of web systems.


The Web, hypertext, and hypermediaHypermedia systems may be one of the most significant contributions to the Internet in recent years. This powerful technology has revolutionised the delivery of e-content thought the Internet.

As user needs change, hypermedia systems themselves have also change. In just the past few years, adaptable and adaptive web systems have emerged.

There are two types of adaptation: adaptability and adaptivity. The former allows users to modify the content presentation and navigation facilities by themselves, and the latter includes systems that adapt to users automatically on the basis of observed user behaviour.


Aims of the moduleΙntroduce this new generation of adaptable and adaptive web systems

Present basic ideas/concepts relevant to their analysis, design, implementation and evaluation

Discuss their benefits, and their implications to user web experience.

These systems can tailor content presentation and navigation support to individual users by taking into account a model of user goals, interests, and preferences.


Objectives

Discuss fundamental concepts of adaptable and adaptive web systemsPresent architectural and user-centered aspects of these systemsPresents user modelling techniquesDiscuss real-world applications


Common questions about Adaptable and Adaptive Web Systems

1. What are adaptable and adaptive web systems and why is there a need for them?

2. What are the advantages for a user?3. How can one develop adaptive web systems

and what are the major challenges that have to be faced in this area?

4. How long will it be before adaptive web systems are available to the every day user?


What are adaptable and adaptive web systems and why is there a need for them?So far web technologies have been directed towards collecting information and providing access to various heterogeneous information resources.

Adaptive web systems have emerged as environments which adapt content, structure, and/or presentation to each individual user’s characteristics, user behavior and/or usage. The notion of adaptation is defined as the concept of making adjustments in a system to accommodate diversity in the user needs and abilities in order to maintain the appropriate context for interaction.


What are adaptable and adaptive web systems and why is there a need for them?Thus, an adaptive web system must :- use hypermedia allowing navigation through the hyperspace of the application domain;- include a user model to describe the user, and- provide an adaptive mechanism for dynamic adaptation of the hypermedia on the basis of the state of the user model.

Adaptation consists of changing content and/or presentation of nodes and links


What are the advantages for a user?

Individuals differ in traits such as skills, aptitudes and preferences for processing information, constructing meaning from information, and applying it to real-world situations. Adaptable and adaptive web systems aim to enhance the mode of delivery of information to the user, increase both flexibility and adaptation of the e-content and of the interface to accommodate the needs of users.


How can one develop adaptive web systems and what are the major challenges that have to be faced in this area?Make distinction between web systems that are customisable – called adaptable systems – and adaptive systems.

An adaptable system allows the user to configure it by changing some parameters, and the system then adapts its behaviour accordingly. This configuration consists of setting user preferences.


How can one develop adaptive web systems and what are the major challenges that have to be faced in this area?

An adaptive system adapts autonomously to current user needs by monitoring the user’s behaviour, recording this behaviour in a user model and adapting dynamically to the current state of the user model. Recording user behaviour captures user’s

browsing actions, answers to questionnaires and the initial information the user may provide. Adaptations can be made by changing predefined

presentations or constructing them out of pieces of information (dynamic page generation).


How can one develop adaptive web systems and what are the major challenges that have to be faced in this area?

Developing Web systems in which both content and navigation support, as well as the user interface are adapted differs from other intelligent applications and hence leads to many new challenges. user modeling: capture the variety of user interests, the time-varying nature of user characteristics and the shift of interest from one type of content to another one using information from user interactions. encoding content, usage data and user models in a way that induction is tractable, decisions are clearly interpretable and personalisation of content and navigation is supported. take into account human factors during design. This involves establishing design guidelines for system development and criteria for system evaluation. defining the type of information needed to establish well defined relationships between user requirements and adaptive functionalities of a system.


Generic architecture of adaptive web system


How long will it be before adaptive web systems are available to the every day user?

This kind of technology could be applied on the current infrastructure of the web, particularly to personalise learning environments, digital libraries, knowledge management systems and other systems. Researchers are already working along this direction. In the future, Semantic Web could facilitate the development of adaptive web-based systems.


The Semantic Web

“The Semantic Web provides a common framework that allows data to be shared and reused across application, enterprise, and community boundaries. It is a collaborative effort led by W3C with participation from a large number of researchers and industrial partners. It is based on the Resource Description Framework (RDF), which integrates a variety of applications using XML for syntax and URIs for naming.” [W3C 2004]

"The Semantic Web is an extension of the current web in which information is given well-defined meaning, better enabling computers and people to work in cooperation." [Tim Berners-Lee, James Hendler, Ora Lassila, The Semantic Web, Scientific American, May 2001]


The Semantic Web

Semantic WebProject by Tim Berners-Lee If successful

Would result in words on Web pages being tagged (using XML) with their meanings

Resource description framework (RDF) Set of standards for XML syntax

OntologySet of standards that defines relationships among RDF standards and specific XML tags


The Semantic Web

The Resource Description Framework (RDF) integrates a variety of applications from library catalogues and world-wide directories to syndication and aggregation of news, software, and content to personal collections of music, photos, and events using XML as an interchange syntax. The RDF specifications provide a lightweight ontology system to support the exchange of knowledge on the Web. http://www.w3.org/


Levels of adaptation

Content level: The content consists of pieces of information that cover the information space. Structure level : This concerns the organisation of the content, i.e. specifying which content items will be visited and how they will be accessed by navigating through the space.Presentation level: This relates to visualising content and elements that support the functionality of a web system.


Levels of adaptation

Adaptive content: selecting different pieces of information, such as texts, images, videos, animation, etc. depending on the user model. For example, an expert in a certain domain is provided with more information than a novice.Adaptive navigation: change link appearance, link target or number of links as well as the order in which links are presented.Adaptive presentation: present different layouts of perceivable user interface elements, such as different type of media, different ordering or different colours, font size, font type or image size.


Adaptation techniques


Modelling human behaviour

Acquire and store information about the user

• Stereotypes: defined by the designer. The system assigns a stereotype to each user.• Explicit information: information supplied by the user is used for example to initialise the user model. • Observation of user behaviour: analysing user actions, goals, interests, or extracting knowledge to describe user behaviour.


Modelling human behaviour

Monitoring user interactions

• links followed or visited• selecting an item from a list or menu• filling-in forms


Topics covered in this module

Adaptive User InterfacesArchitectural Aspects of Adaptive Web SystemsUser ModellingAuthoring of Adaptive Web SystemsRepresenting and Modelling Data and InformationApplication ExamplesEvaluation Methodologies


Reading materials

Lecture slidesChen S. and Magoulas G.D., Adaptable and Adaptive Hypermedia Systems, IRM Press, 2005.Journal and conference papers (available online)


Useful reading for this and the next lecture

P. Brusilovsky, Adaptive Hypermedia, User Modelingand User-Adapted Interaction, vol. 11, pp. 87-110, 2001.P. Brusilovsky, Methods and techniques of adaptive hypermedia, User Modeling and User Adapted Interaction, vol. 6, pp. 87-129, 1996.

Both available at www2.sis.pitt.edu/~peterb/papers.html

Documents

Adaptable and Adaptive Web Information