Adaptable and Adaptive Web Information Systems School of Computer Science and Information Systems Birkbeck College University of London Lecture 1: Introduction George Magoulas gmagoulas@dcs.bbk.ac.uk October 14, 2005 www.dcs.bbk.ac.uk/~gmagoulas/ 1
Contents The Web, hypertext and hypermedia Aims and objectives of the module Common questions about Adaptive Web Systems Levels of adaptation and techniques Modelling human behaviour Topics covered in this module Reading materials October 14, 2005 www.dcs.bbk.ac.uk/~gmagoulas/ 2
The Web, hypertext, and hypermedia Internet : vast collection of interconnected networks that all use the TCP/IP protocols October 14, 2005 www.dcs.bbk.ac.uk/~gmagoulas/ 3
The Web, hypertext, and hypermedia 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. October 14, 2005 www.dcs.bbk.ac.uk/~gmagoulas/ 4
The Web, hypertext, and hypermedia Hypertext Transfer Protocol (HTTP) is the set of rules for delivering Web pages over the Internet HTTP uses the client/server model The client opens an HTTP session and sends a request to a server The 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. October 14, 2005 www.dcs.bbk.ac.uk/~gmagoulas/ 5
The Web, hypertext, and hypermedia Hypertext 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 October 14, 2005 www.dcs.bbk.ac.uk/~gmagoulas/ 6
The Web, hypertext, and hypermedia Hypertext 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] October 14, 2005 www.dcs.bbk.ac.uk/~gmagoulas/ 7
The Web, hypertext, and hypermedia Hypermedia 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 organisation of the text or multimedia content. The activity whereby the user accesses a node by following links is called navigation. October 14, 2005 www.dcs.bbk.ac.uk/~gmagoulas/ 8
The Web, hypertext, and hypermedia Hypermedia 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. October 14, 2005 www.dcs.bbk.ac.uk/~gmagoulas/ 9
The Web, hypertext, and hypermedia 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. October 14, 2005 www.dcs.bbk.ac.uk/~gmagoulas/ 10
The Web,, hypertext, and Users may fail to get an overview of how all the hypermedia 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. October 14, 2005 www.dcs.bbk.ac.uk/~gmagoulas/ 11
The Web, hypertext, and hypermedia Hypermedia 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. October 14, 2005 www.dcs.bbk.ac.uk/~gmagoulas/ 12
Aims of the module Ιntroduce 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. October 14, 2005 www.dcs.bbk.ac.uk/~gmagoulas/ 13
Objectives Discuss fundamental concepts of adaptable and adaptive web systems Present architectural and user-centered aspects of these systems Presents user modelling techniques Discuss real-world applications October 14, 2005 www.dcs.bbk.ac.uk/~gmagoulas/ 14
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? October 14, 2005 www.dcs.bbk.ac.uk/~gmagoulas/ 15
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. October 14, 2005 www.dcs.bbk.ac.uk/~gmagoulas/ 16
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 October 14, 2005 www.dcs.bbk.ac.uk/~gmagoulas/ 17
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. October 14, 2005 www.dcs.bbk.ac.uk/~gmagoulas/ 18
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. October 14, 2005 www.dcs.bbk.ac.uk/~gmagoulas/ 19
How can one develop adaptive web systems and what are the An adaptive system adapts autonomously to major current user challenges needs by monitoring that have the to user s be faced behaviour, in recording this area? 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). October 14, 2005 www.dcs.bbk.ac.uk/~gmagoulas/ 20
How can one develop adaptive web systems and what are the Developing Web systems in which both content and major navigation challenges support, as well as that the user have interface to be are adapted differs from other intelligent applications and hence leads to faced many new in challenges. this area? 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 October adaptive 14, 2005 functionalities of www.dcs.bbk.ac.uk/~gmagoulas/ a system. 21
Generic architecture of adaptive web system October 14, 2005 www.dcs.bbk.ac.uk/~gmagoulas/ 22
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. October 14, 2005 www.dcs.bbk.ac.uk/~gmagoulas/ 23
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] October 14, 2005 www.dcs.bbk.ac.uk/~gmagoulas/ 24
The Semantic Web Semantic Web Project 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 Ontology Set of standards that defines relationships among RDF standards and specific XML tags October 14, 2005 www.dcs.bbk.ac.uk/~gmagoulas/ 25
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/ October 14, 2005 www.dcs.bbk.ac.uk/~gmagoulas/ 26
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. October 14, 2005 www.dcs.bbk.ac.uk/~gmagoulas/ 27
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. October 14, 2005 www.dcs.bbk.ac.uk/~gmagoulas/ 28
Adaptation techniques October 14, 2005 www.dcs.bbk.ac.uk/~gmagoulas/ 29
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. October 14, 2005 www.dcs.bbk.ac.uk/~gmagoulas/ 30
Modelling human behaviour Monitoring user interactions links followed or visited selecting an item from a list or menu filling-in forms October 14, 2005 www.dcs.bbk.ac.uk/~gmagoulas/ 31
Topics covered in this module Adaptive User Interfaces Architectural Aspects of Adaptive Web Systems User Modelling Authoring of Adaptive Web Systems Representing and Modelling Data and Information Application Examples Evaluation Methodologies October 14, 2005 www.dcs.bbk.ac.uk/~gmagoulas/ 32
Reading materials Lecture slides Chen S. and Magoulas G.D., Adaptable and Adaptive Hypermedia Systems, IRM Press, 2005. Journal and conference papers (available online) October 14, 2005 www.dcs.bbk.ac.uk/~gmagoulas/ 33
Useful reading for this and the next lecture P. Brusilovsky, Adaptive Hypermedia, User Modeling and 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 October 14, 2005 www.dcs.bbk.ac.uk/~gmagoulas/ 34