Methods and techniques of adaptive hypermedia

Adaptive hypermedia is a new direction of research within the area of adaptive and user model-based interfaces. Adaptive hypermedia (AH) systems build a model of the individual user and apply it for adaptation to that user, for example, to adapt the content of a hypermedia page to the user's knowledge and goals, or to suggest the most relevant links to follow. AH systems are used now in several application areas where the hyperspace is reasonably large and where a hypermedia application is expected to be used by individuals with different goals, knowledge and backgrounds. This paper is a review of existing work on adaptive hypermedia. The paper is centered around a set of identified methods and techniques of AH. It introduces several dimensions of classification of AH systems, methods and techniques and describes the most important of them.     

Webvise: browser and proxy support for open hypermedia structuring mechanisms on the World Wide Web

This paper discusses how to augment the World Wide Web with an open hypermedia service (Webvise) that provides structures such as contexts, links, annotations, and guided tours stored in hypermedia databases external to the Web pages. This includes the ability for users collaboratively to create links from parts of HTML Web pages they do not own and support for creating links to parts of Web pages without writing HTML target tags. The method for locating parts of Web pages can locate parts of pages across frame hierarchies and it also supports certain repairs of links that break due to modified Web pages. Support for providing links to/from parts of non-HTML data, such as sound and movie, will be possible via interfaces to plug-ins and Java-based media players.The hypermedia structures are stored in a hypermedia database, developed from the Devise Hypermedia framework, and the service is available on the Web via an ordinary URL. The best user interface for creating and manipulating the structures is currently provided for the Microsoft Internet Explorer 4.x browser through COM integration that utilizes the Explorer's DOM representation of Web-pages. But the structures can also be manipulated and used via special Java applets and a pure proxy server solution is provided for users who only need to browse the structures. A user can create and use the external structures as `transparency' layers on top of arbitrary Web pages, the user can switch between viewing pages with one or more layers (contexts) of structures or without any external structures imposed on them.     

Hypermedia systems without links

Although there is no universally accepted definition of what a hypermedia system really is, most hypermedia specialists seem to agree on one basic issue. A hypermedia system contains some pieces of information (often called nodes or chunks) that are tied together by links. Links in fact have almost become a defining characteristic of hypermedia.In this paper we contend that the importance of links has been grossly exaggerated. Hypermedia systems in which links play only a limited role are quite conceivable. Indeed, many burning issues in current day hypermedia systems can be better resolved if other navigational techniques are used. We believe that the emphasis on links has caused a rather myopic view of hypermedia systems. A serious re-evaluation of the extent to which links are beneficial is important. This fact has been previously observed by others, the earliest being Van Dam's keynote address at 'Hypertext'87'. In this paper we propose a first significant step in using structure to replace links.     

Storing user experiences in mixed reality using hypermedia

This paper describes HyperMem, a system to store and replay user experiences in mixed environments. The experience is stored as a set of hypermedia nodes and links, with the information that was displayed along with the video of the real world that was navigated. It uses a generic hypermedia model, implemented as software components, to handle mixed reality environments. This model includes components for storing and replaying experiences and integrating them in the overall set of hypermedia graphs that can be accessed by a given user. The paper presents the goals of the system, the underlying hypermedia model, the application scenarios, and the architecture and tools for replaying and repurposing stored information.     

CAI中的智能超媒体技术研究

将智能化行为引入到超媒体系统中,在超媒体的链和结点中嵌入知识或规则,允许链进行计算和推理,使链具有动态跟踪与动态引导功能,使得媒体信息具有更丰富的表现特性,这是智能超媒体的主要研究的内容。文章探讨了智能超媒体的相关实现技术,建立了ＣＡＩ领域的相关知识与推理模型,设计与实现了网上多媒体ＣＡＩ系统中的智能超媒体功能。     

Engineering the Design of Usable Hypermedia

This paper presents a systematic method for designing hypermedia that are easy to use for various types of users, along with its application to a specific case study. The design phase is supported by the use of task models. We have identified criteria that indicate how information in task models can be used to identify links, design presentations, and structure the data of the hypermedia considered. Different types of users imply different task models and thus different hypermedia designs. We then show how the design obtained was evaluated using both empirical testing and metrics for hypermedia navigation. We discuss the results obtained by these two evaluation methods and how they affected the original design.     

The effects of hypermedia knowledge and learning style on the construction of group concept maps

This study involved 20 research participants who created group concept maps on the term “hypermedia.” The purpose of the study was to determine whether groups, membership of which was based on a mixture of learning styles or a mixture of hypermedia knowledge, constructed concept maps that differed in terms of number of concepts, number of nodes, number of links, number of bidirectional links, number of multiple concept nodes, number of nodes with multiple links, and varying levels of hierarchical relationships. It was found that the group comprised of two convergers, one assimilator, and one diverger, all of whom had a high level of hypermedia knowledge, was the most productive. Of the 11 measures, they produced the most for 7 of them. We were also interested in determining the interactive dynamics that either learning style or hypermedia knowledge played as the participants constructed their group concept maps. We audiotaped their interactions and categorized their comments and actions within the learning style traits associated with being either a converger, a diverger, an assimilator, or an accommodator. Learning style seemed to explain the types of interactions more than hypermedia knowledge did.     

基于结构特性的超媒体模型

将超媒体的结构特性与形式语言学理论相结合,提供了一种有效地分析超媒体动态结构的特性的方法,该方法将超毁体组件集合映射为语言中的抽象符号集合,组件集合之上的链映射为语言中建立单词的方法,超媒体的结构化机械制映射为语言中的抽象符号集号,组件集合之上的链映射为语言中建立单词的方法,超媒体的结构化机制映射为语言中描述单词集合构造机制的语法,超媒体模拟为转换机,“链引导”动作模拟为“匹配对”序列,“链引导”的计算结果产生与上下文无关文法相对应的虚拟文档,从而为进一步研究超媒体的浏鉴语义及其它动态特性提供了理论基础。     

Adaptive Hypermedia

Adaptive hypermedia is a relatively new direction of research on the crossroads of hypermedia and user modeling. Adaptive hypermedia systems build a model of the goals, preferences and knowledge of each individual user, and use this model throughout the interaction with the user, in order to adapt to the needs of that user. The goal of this paper is to present the state of the art in adaptive hypermedia at the eve of the year 2000, and to highlight some prospects for the future. This paper attempts to serve both the newcomers and the experts in the area of adaptive hypermedia by building on an earlier comprehensive review (Brusilovsky, 1996; Brusilovsky, 1998).     

A User-Configurable Hypermedia-Based Interface Via the Functional Model of the Link

Hypermedia management systems often make use of database management systems for the persistent storage of links and of the linked information components. In this paper, we argue that a hypermedia management system with its support for reader-directed navigation provides an attractive type of database system interface in that it facilitates ease of database access or more specifically, of locating (‘discovering’) relevant information.

Furthermore, our approach to hypermedia management, based on the Functional Model of the link, provides for extensive user-configurability of that interface. This configurability particularly applies to fully dynamic links, which free the user from much of the link creation and maintenance duties.

A prototype system incorporating this approach is overviewed in this paper.     

Supplementing virtual documents with just-in-time hypermedia functionality

Digital library systems and other analytic or computational applications create documents and display screens in response to user queries “dynamically” or in “real time.” These “virtual documents” do not exist in advance, and thus hypermedia features (links, comments, and bookmark anchors) must be generated “just in time”—automatically and dynamically. In addition, accessing the hypermedia features may cause target documents to be generated or re-generated. This article describes the specific challenges for virtual documents and dynamic hypermedia functionality: dynamic regeneration, and dynamic anchor re-identification and re-location. It presents Just-in-time Hypermedia Engine to support just-in-time hypermedia across digital library and other third-party applications with dynamic content, and discusses issues prompted by this research.     

A framework for automatic semantic video annotation

Hypermedia composite templates define generic structures of nodes and links to be added to a document composition, providing spatio-temporal synchronization semantics. This paper presents EDITEC, a graphical editor for hypermedia composite templates. EDITEC templates are based on the XTemplate 3.0 language. The editor was designed for offering a user-friendly visual approach. It presents a new method that provides several options for representing iteration structures graphically, in order to specify a certain behavior to be applied to a set of generic document components. The editor provides a multi-view environment, giving the user a complete control of the composite template during the authoring process. Composite templates can be used in NCL documents for embedding spatio-temporal semantics into NCL contexts. NCL is the standard declarative language used for the production of interactive applications in the Brazilian digital TV system and ITU H.761 IPTV services. Hypermedia composite templates could also be used in other hypermedia authoring languages offering new types of compositions with predefined semantics.     

Hypermedia Design Methodology in World Wide Web Applications

One approach to instruction based on a "learner-centered" view of learning is to provide rich environments in which learners can actually build their own knowledge. Therefore only educational software, carefully designed, can improve the efficiency of courseware. Within this framework, the World Wide Web provides a unique support for course material. Using a generalized hypermedia instructional design methodology, we integrated a hypermedia instructional module with simulation additional tools into an academic information system. This academic information system is a computer-supported environment in which collaborative discourse is the primary medium for knowledge advancement in the area of power electronics. It can be explored by learners in that they have both contextual access to knowledge displayed in a hypertext format and access to real experiences by means of simulation. In this article, we present an object-orientated approach that integrates the complete graphic user interface development.     

Knowledge maps for e-learning

Maps such as concept maps and knowledge maps are often used as learning materials. These maps have nodes and links, nodes as key concepts and links as relationships between key concepts. From a map, the user can recognize the important concepts and the relationships between them. To build concept or knowledge maps, domain experts are needed. Therefore, since these experts are hard to obtain, the cost of map creation is high. In this study, an attempt was made to automatically build a domain knowledge map for e-learning using text mining techniques. From a set of documents about a specific topic, keywords are extracted using the TF/IDF algorithm. A domain knowledge map (K-map) is based on ranking pairs of keywords according to the number of appearances in a sentence and the number of words in a sentence. The experiments analyzed the number of relations required to identify the important ideas in the text. In addition, the experiments compared K-map learning to document learning and found that K-map identifies the more important ideas.     

Automating Hypermedia for Decision Support

Many ‘first generation’ hypermedia systems were designed to support applications, which do not require the dynamic and general characteristics necessary for our domain --- decision support systems (DSS). The heart of our research is a dynamic model of hypermedia incorporating virtual structures and computation, which we call generalized hypermedia. Generalized hypermedia broadens and automates the ‘static’ or non-virtual notion of first generation hypermedia for a knowledge-based DSS shell. The shell provides a hypermedia-style interface for navigating among DSS application models, data and reports. Such a shell should support applications in a variety of fields, e.g., engineering, manufacturing, finance, and therefore must provide hypermedia support as general, system-level functionality Generalized hypermedia superimposes a hypermedia network on a DSS application, generating all hypermedia nodes, links and link markers dynamically from the application's standard, non-hypermedia knowledge base. In this paper we demonstrate how automating hypermedia can enhance decision making with a DSS. We describe generalized hypermedia and discuss the challenges presented to it by a dynamic, real-time environment.     

Personalization in an interactive learning environment through a virtual character

Traditional hypermedia applications present the same content and provide identical navigational support to all users. Adaptive Hypermedia Systems (AHS) make it possible to construct personalized presentations to each user, according to preferences and needs identified. We present in this paper an alternative approach to educational AHS where a virtual character personalizes the interaction with the user through the use of a particular recommender system. The character has natural language communication abilities; it can learn students’ profiles and use this knowledge to recommend appropriate contents and activities. Through its interaction with the user, the character is able to collect and organize information about students in order to identify appropriate suggestions of contents. The recommender system employs a knowledge representation scheme that is easy to understand and to modify, enabling teachers/tutors to explore the types of recommendations being made and to appreciate why they are made. An experiment with computer science students was carried out in order to validate the approach proposed. The results of the experiment showed that the presentation of personalized links through a virtual character had a positive impact in the users’ perception of the system as a learning tool. The combination of the virtual character with a recommender system proved to be a good alternative for the delivery of personalized contents without making constant changes in the main user interface. This approach provides mechanisms to guide users through paths of study followed by students with similar profiles, without violating the human–computer interaction principle of perceived stability.     

Automatic generation of instructional hypermedia with APHID

This research investigates the use of patterns in designing adaptable, flexible hypermedia applications. While patterns are particularly applicable to software design, they can also be used to assist designers of other types of applications. We have developed a method (APHID) that guides a hypermedia creator through the analysis and design process. The method ensures that good design principles are followed, both for the hypermedia application and for the interface that presents the hypermedia application. Our method uses a concept map, constraints, and patterns (instructional and presentation) to support partial automation for creating hypermedia applications. We also present a prototype software system that uses the APHID method to create instructional hypermedia applications semi-automatically. The applications created using APHID are tailored to specific types of learners. We conclude with a claim that this approach is applicable not just to instructional hypermedia, but to the larger problem of generating adaptable interfaces.     

A personalized semantic portal for enhanced user support

Although many advances have been made in semantic portal research, often links to relevant pages are not shown and the same content/links are presented to users that have different background and interests. This paper introduces a novel semantic portal, SEMPort, to support the browsing of users based on personalization and enriched semantic hyperlinks. Our semantic portal makes a novel contribution by integrating adaptive hypermedia methods and enriched semantic hyperlinks into semantic portal technologies to provide better navigation. SEMPort supports different personalization such as adaptive link sorting and adaptive link annotation based on interests of individual users. Enriched semantic links are also supplied to guide users to relevant pages. In addition, easy-to-use and real-time content maintenance mechanisms are provided, which is important for the evolution of the content. Evaluations carried out to assess the semantic portal include performance evaluations, interface usability using Nielsen's heuristics and empirical user studies. This paper also provides an overview and comparison to the state-of-the-art as well as outlining future directions for semantic portals.     

A Fuzzy-Based Approach to Stereotype Selection in Hypermedia

This paper presents a stereotype-based user model for adaptive hypermedia systems. We use a suitable algebraic fuzzy structure which can adequately reflect some features of the user in the model, and apply this model to adapt the navigation and the content of hypermedia nodes to the user's needs. The model includes temporal representations of the user and approximates every real user by a set of stereotypes, from which the one realizing the best approximation can always be extracted. The set of stereotypes is the support set of the structure and the operations defined therein may be supplied with adequate semantics which allow for the selection of the stereotype.     

The development of a sound viewer for an open hypermedia system

Abstract

While rich support for a wide variety of media such as text, video and image is common among contemporary hypermedia systems, so too is the inadequate support for audio. The primary reason that audio has not attracted as much attention as other media can be attributed to its obvious lack of visual identity. The main focus of this work was to identify a generic and meaningful visual representation of audio within a hypermedia context, and significantly promote hypermedia support for audio through the provision of a sound viewer.

This paper describes the inherent difficulties in providing a consistent interface to audio, and discusses in some depth the issues raised during the development process. The sound viewer is then introduced and the associated concepts described. The creation and traversal of links to and from audio are facilitated by the sound viewer across formats including WAV (proprietary digital sound file format from Microsoft), CD (Compact Disc) Audio and MIDI (Musical Instrument Digital Interface). The resultant viewer provides a unified and extensible framework for interacting with audio from within an open hypermedia environment. The open hypermedia system Microcosm was used as the development platform for this work. Microcosm can be augmented to supply a hypermedia link service to additional media with minimal overhead.