Hypertext Functionality: introduction to the special issue
Until recently, few system developers actively thought about an application's interrelationships, and whether users should access and navigate along these relationships directly. Researchers in the area of hypertext functionality (HTF) believe that relationship and navigational support will make everyday business, scientific, engineering and personal applications richer and more effective. Developers could understand their applications at a new and deeper level, and have an alternative way of presenting and giving access to information. Users could gain direct access to all aspects and related information about objects of interest. Structural and relationship-based navigation would give them more effective control over interaction with the application. These features would enable users to understand the application, its contents and its information domain more deeply. This is the promise of the HTF approach and, we expect, the future of application development.
The Web finally provides a platform for widespread HTF support. Few Web applications (and even fewer off the Web), currently take more than modest advantage of hypertext [BV97, BVA97]. Thus, HTF researchers have the opportunity to make a major impact on how applications of the future will look, and on the level of support and quality of interaction that users will come to expect.
A note on our terminology: we view the terms "hypertext" and "hypermedia" as synonymous; nominally hypermedia applies hypertext concepts to all media forms. We use the term "application" broadly to cover application systems and application packages, as well as individual documents, worksheets and programs written under these.
Hypertext is a concept that encourages authors to structure information as an associative network of nodes (documents or simply information chunks) and interrelating links. This frees authors from the linear, sequential structure that dominates most printed documents. Presenting information as an associative network enables readers to access information in the order most appropriate to their purposes, freeing them from obeying the linear ordering implied within printed documents. Many hypertext implementations also allow readers to become authors (temporarily, at least) by adding comments (annotations) and additional links among what they read. In all these ways hypertext promotes options and choice. Hypertext techniques provide the tools for "relationship management" [ISB95], that is, for creating, storing, maintaining, retrieving, filtering, customizing, presenting, annotating and navigating information objects and relationships (nodes and links).
A suite of hypertext functionalities builds on relationships, augmenting applications with structuring, navigation and annotation, features [BVA97, Ni95]. Structuring functionality includes local and global information overviews; alternate views and contexts; context-preserving transclusions; link propagation; node, link and anchor typing; as well as keywords and other attributes on all of these. Navigation encompasses access ranging from information retrieval to browsing. This includes content- and structure-based query; history-based navigation and sophisticated backtracking; bi-directional linking; dynamic and computed linking; and process enactment through link traversal. Annotation includes bookmarks, landmarks, manual linking and commenting. Note that many of these features can be shared in collaborative environments. Many also can be personalized for different users and tasks.
The HTF approach supplements applications with hypertext functionality in order to enhance their effectiveness [Oi95, Oi97, Bi99]. People will not abandon the applications they use everyday in favor of ones that offer hypertext; therefore developers must find it relatively easy to integrate hypertext functionality into the everyday applications that people use. Augmenting applications with hypermedia functionality should result in new ways to view a system's knowledge and processes conceptually, to navigate among items of interest and task stages, to enhance a system's knowledge with comments and relationships, and to target information displays to individual users and their tasks.
The HTF approach fosters three major categories of research:
- designing HTF (as part of general application design)
- integrating HTF into applications
- using HTF to improve personal and organizational effectiveness.
Rossi, Schwabe and Garrido present the Object-Oriented Hypermedia Design Methodology (OOHDM). Many everyday applications are "computational" in that their display content is generated as a result of calculations and other algorithms. HTF support for computational applications must be integrated seamlessly into the application's computational or "behavioral" component. OOHDM is a well-established hypermedia design methodology comprising four major activities: conceptual modeling, navigational design, abstract interface design and implementation. The authors describe OO-Navigator, a reusable software framework supporting OOHDM, composed of a set of classes that can be plugged into the application's components to implement navigation behavior. The paper then presents a broad range of hypermedia design patterns to help developers using any design methodology to incorporate hypertext support. The resulting OOHDM design can be implemented on almost any hypermedia-supported platform.
Verbyla and Watters describe three approaches to integrating HTF into applications. The first, retrofitting HTF into an application, involves incorporating hypertext features into the actual application source code. Several hypertext toolkits have been developed for this. The second customizes access through the application programming interface (API). The application code need not be altered in this approach, but separate customizations must be created for every application. (OO-Navigator and DHymE [Bi99] take this approach.) The paper focuses on the third approach: Hypermedia Management Systems (HMSs) that "cooperate" or collaborate with third-party software to provide full hypertext functionality. Research in the open hypermedia systems field takes this approach. The HMS manages much of the hypertext functionality on behalf of the applications, which make calls to the HMS when this functionality is needed. In Verbyla and Watters' new cooperative model, the HMS stores link type specifications (describing classes of links both within and among applications) that resolve to individual links only at run-time. Such dynamic links can also invoke computation and thus enact processes.
Process enactment is also a major theme in Noll and Scacchi's paper. Their Distributed Hypertext Framework (DHT) supports software engineering teams within virtual enterprises, i.e. distributed teams that work together on a specific project and then disband. The hypertext framework provides the key tool for coordinating the information objects, tools, work processes and collaboration among the team members, given the absence of a shared central repository or central coordination mechanism, which characterizes virtual enterprises. DHT provides both the logical and physical architecture for a virtual repository underlying collaborative information-sharing workspaces. It includes hypertext features for software process modeling, and enacting the various software engineering tasks through navigating the process model. Noll and Scacchi discuss DHT both in terms of integrating HTF into the application environment (logical, physical and process integration), and in terms of enhancing the software engineering activity.
Using HTF to make the software development process more effective turns out to be a theme of several papers in this special issue. Oinas-Kukkonen and Rossi contrast automatically-generated hypertext and manually-crafted hypertext support of software engineering environments. The paper first details how OO-Navigator can map HTF to a computer-aided software engineering (CASE) environment. It next describes the Linking Ability system which uses HTF as a communications tool for linking between pieces of software documents, annotating the design documents and managing discussion of design rationale among the members of the development team. It then contrasts automated and manual linking, noting the strengths of each approach and discussing issues such as granularity, soundness, quality and completeness.
Selvin elaborates on supporting design rationale and team communications. He describes Conversational Modeling, an extension of argumentation-based hypertext systems to support large-scale discussions among groups of people. His application, in use at Bell Atlantic, supports both formal model-building as part of collaborative analysis, and exploratory, informal discussion. Representing information in a node and link structure helps people construct meaning from complex domain-specific models in the network engineering domain. This paper illustrates several complex models that the application represents.
These papers extend shorter papers presented at various Hypertext Functionality Workshops. Since 1994, the HTF research community has organized many workshops [HTF1, 2, 3, 4, 5, 7] and more are scheduled. HTF research closely parallels research in organizational hypermedia - hypertext support of the information systems field. Since 1993 the primary forum for this research has been the Hypermedia in Information Systems and Organizations minitrack at the Hawaii International Conference on Systems Sciences [HICSS93]. A special journal issue also resulted from this forum [JOC96]. In 1998 this minitrack was expanded into the Web Information Systems minitrack [HICSS98], recognizing the Web as today's primary platform for hypertext development.
Yet, as we noted earlier, most Web applications make meager use of linking and other
HTF support [BVA97]. When developers convert applications to or
develop new applications on the Web, they rarely incorporate links beyond a home
page and an index, and sometimes connecting screens with previous and next links.
Why do they not take full advantage of the Web's hypertext infrastructure?
[BV97] In part, it has not occurred to many of them to
incorporate HTF. Most software developers do not have a hypertext mindset;
developers and users have seen few examples and do not demand this functionality
yet. In part, those migrating often do not have time to reengineer their application
beyond its current capabilities; and developers have few tools and techniques to
incorporate HTF easily. The hypertext and HTF research communities are developing
design techniques and integration tools for the software development communities,
and an increasing number of examples are emerging. Over time we hope to change the
software development mindset to enhance each new application automatically with HTF.
Users of the future will come to expect HTF support, and developers will have the
tools and experience to deliver. This is the promise of HTF. We call on developers
and researchers of all related fields to employ and contribute to HTF to make this
potential a reality.
AcknowledgementsMichael Bieber gratefully acknowledges funding for his work, as reported in this special issue, by the NASA JOVE faculty fellowship program, by the New Jersey Center for Multimedia Research, by the National Center for Transportation and Industrial Productivity at the New Jersey Institute of Technology (NJIT), by the New Jersey Department of Transportation, and by the New Jersey Commission of Science and Technology.
References[Bi99] Bieber, M. (1999) "Supplementing Applications with Hypermedia". ACM Transactions on Information Systems, to be published
[BVA97] Bieber, M., Vitali, F., Ashman, H., Balasubramanian, V. and Oinas-Kukkonen, H. (1997) "Fourth Generation Hypermedia: Some Missing Links for the World Wide Web". International Journal of Human Computer Studies, Vol. 47, 31-65
[HICSS93] Bieber, M. and Isakowitz, T. (eds) (1993) "Hypermedia in Information Systems and Organizations". Proceedings of the 26th Hawaii International Conference on System Sciences, volume 3 (IEEE Press: Washington, D.C.)
[HTF1] Bieber, M. and Oinas-Kukkonen, H. (eds) (1994) Proceedings of the First International Workshop on Incorporating Hypertext Functionality Into Software Systems (HTF I), at the European Conference on Hypermedia Technologies (ECHT94), Edinburgh, September
[HTF2] Ashman, H., Balasubramanian, V., Bieber, M. and Oinas-Kukkonen, H. (eds) (1996) Proceedings of the Second International Workshop on Incorporating Hypertext Functionality Into Software Systems (HTF II), at the Hypertext96 Conference, Bethesda, March
[HTF3] Ashman, H., Balasubramanian, V., Bieber, M. and Oinas-Kukkonen, H. (eds) (1997) Proceedings of the Third International Workshop on Incorporating Hypertext Functionality Into Software Systems (HTF III), at the Hypertext97 Conference, Southampton, UK, April
[HTF4] Watters, C. and Vitali, F. (eds) (1998) Proceedings of the Fourth International Workshop on Incorporating Hypertext Functionality Into Software Systems (HTF IV), at the 7th International World Wide Web Conference, Brisbane, April
[HTF5] Rossi, G. and Ziv, H. (eds) (1998) Proceedings of the Fifth International Workshop on Incorporating Hypertext Functionality Into Software Systems (HTF V), at the International Conference on Software Engineering, Kyoto, April
[HTF7] Kuutti, K. and Oinas-Kukkonen H. (eds) (1998) Proceedings of the Seventh International Workshop on Hypertext Functionality: Organizational Memory Systems and HTF (HTF VII), at the International Conference on Information Systems (ICIS '98), Helsinki, December
[Oi95] Oinas-Kukkonen, H. (1995) "Developing Hypermedia Systems: The Functionality Approach". Proceedings of the Second Basque International Workshop on Information Technology (BIWIT '95): Data Management Systems, San Sebastian, Spain, July (IEEE Computer Society Press: Los Alamitos, CA), pp. 2-8
[Oi97] Oinas-Kukkonen, H. (1997) "Embedding Hypermedia into Information Systems". Proceedings of the Thirtieth Hawaii International Conference on System Sciences, volume VI, Maui, Hawaii, January, pp. 187-196