Scholarly work, digital library, hypermedia technology, work practices, collaborative work.

The HyTech Digital Library Project focuses on development of hypermedia technology for a special kind of digital library that provides support for scholarly work. This paper presents the requirements for HyTech, which were identified by analyzing a particular case study namely ACM SIGWEB's Digital Library Project.

Libraries are much more than physical collections of data. They are institutions that filter and select information based on space, cost, relevance, and quality criteria; professionals (librarians) that generate metadata about their collections and offer support to their patrons; social organizations that provide a basis for collaborative work; and much more. The degree to which digital libraries can and will assume these and other roles has been and continues to be the subject of much research. Above all, it is clear that digital libraries are much more than electronic collections of data – they are virtual analogs to the complex organizations that are physical libraries. [2,4,6]

Inspired by Levy and Marshall [5], we envision digital libraries as being more than a relatively permanent and fixed archival collection of digital material to be browsed and queried by information-seeking individuals. A digital library is a versioned (fixed and fluid) and interconnected collection of both permanent and transient documents that allows collaborative as well as individual work practices. In this way, digital libraries can augment rather than simply automate the set of services provided by physical libraries.

In essence, digital libraries offer much promise for patrons and many challenges for system designers and developers. Digital library systems are complex software systems that are used to store, catalogue, access, share, and disseminate digitized information. A digital library system incorporates a large number of distributed heterogeneous tools, user interfaces and services to access (and update) diverse collections of highly interrelated documents of various formats (text, images, audio, video, etc.) located in heterogeneous information repositories distributed across a network.

The HyTech (from Hypermedia Technology) Digital Library Project focuses on development of hypermedia technology for a special kind of digital library that provides support for scholarly work. HyTech has two main goals: to develop advanced hypermedia technology and, to deploy the developed technology in a digital library setting. The development and deployment has been driven by the requirements that arise from analyzing a specific digital library project: ACM SIGWEB's Digital Library Project (called HyNIC) focusing on scholarly work. HyNIC is an international initiative to build a digital library encompassing the large body of research material accumulated in the hypermedia community [3]. Both research and education activities can benefit from using HyNIC. Researchers get easy access to previous research publications, and teachers and students can use HyNIC in their classes. The HyNIC problem domain will serve as an excellent deployment testbed for and provide useful feedback concerning the hypermedia technology developed in HyTech.

HyTech focuses on a small subset of the overall infrastructure and services of a typical digital library system. We provide support for new work practices that have to do with adding information and adding structure over the information in a digital library. These work practices (that are vital to a digital library for scholarly work) are supported for different cooperation modes ranging from individual work to different collaborative work settings. In particular, we provide hypermedia structuring mechanisms, hypermedia navigation mechanisms, collaboration mechanisms, and versioning mechanisms to digital library users.

HyTech has two concurrent activities, the development activity and the deployment activity. The development activity had a head start. Prototypes from almost a decade of research into design, development, deployment, and assessment of hypermedia technology (e.g., [7,8]) provided a solid basis for initial development. The initial deployment activity involved an analysis of the problem domain. This resulted in a set of requirements specific for scholarly work that helped focus the development.

HyNIC will operate with very large data collections that are physically distributed among servers that run at different Internet domains. The user base will be large and will consist of researchers, teachers, students, system developers, etc. that are placed around the world and access (and update) the data over the Internet.

Indexing, search, query, and information retrieval are important work practices of any library (physical or digital). Many digital library projects are already focusing on providing support for these features [2,4]. HyTech focuses on supporting the subset of the overall infrastructure and services of a digital library system that are particularly relevant for scholarly work. In particular, we have found the following work practices to be essential for scholarly work:

1. Adding new and updating existing material in the digital library data collection. Search and retrieval of information are, obviously, the most commonly used operations in a digital library system. However, it is also vital to be able to add new material (e.g., research papers, paper collections, presentation slides, and video clips) to the library collection and to update existing material in the library (e.g., by adding a new updated version of a research paper). A digital library for research material will be updated daily by many different persons that make their research material available to the research community.
2. Adding hypermedia structure over existing material in the digital library data collection. The ability to add structure over the information adds a new and powerful dimension to the concept of a library that distinguishes a digital library from a physical library. Users are able to overlay the library material with their personal structure. Students may find this feature particular useful, since this will help them organize and get an overview of the material in the library.
3. Browsing (navigating) hypermedia structures in the digital library data collection. It is quite important that users can view and browse the available structure in the digital library. Just like the data material itself, structure contains important information (i.e., about relations between particular pieces of data).

The above work practices should be supported for different modes of cooperation between users:

1. Individual work (users working on a data collection in isolation).
2. Asynchronous work (users working on the same data collection at different times).
3. Loosely coupled work (users working on the same data collection at the same time with awareness of each other).
4. Tightly coupled work (users working on the same data collection at the same time with synchronized views and tools).

Current work practices in a physical library already encompass individual work practices as well as different types of collaborative work practices. A digital library should allow these work practices to be distributed in both time and space [1].

To provide support for the proposed work practices in different modes of cooperation, the development work needs to focus on providing services from the following areas:

1. Hypermedia structuring mechanisms. Associative structures or linking is by far the most well-known hypermedia structuring mechanism due to the World Wide Web. However, other types of hypermedia structuring mechanisms such as spatial and taxonomic structures have proven to be very useful in digital libraries [6].
2. Hypermedia navigation mechanisms. Link traversal (again due to the World Wide Web) is the most commonly known hypermedia navigation mechanism. Other types of navigation mechanisms have proven valuable in previous hypermedia system research such as querying, graphical overviews, local and global maps, guided tours, tabletops, fish-eye views, paths, trails, spatial hypertext, etc.
3. Collaboration mechanisms. Core CSCW mechanisms such as support for sessions and different coupling modes are essential to provide basic collaboration mechanisms in a digital library.
4. Versioning mechanisms. A versioning mechanism should allow data collections to evolve over time (both by adding new material and by updating existing material) without destroying old versions of material. It should be possible to maintain and work with several different versions of some pieces of material. Since structure also contains important information, a versioning mechanism should also allow the structure over the data collections to be versioned.

The matrix in Figure 1 shows the coherence between work practices on the one axis and cooperation modes on the other axis. The fields in the matrix list the (hypermedia) technologies and services that are necessary to support the work practice in the specific cooperation mode. Versioning mechanisms are necessary to support addition of new material in the data collections. Structuring mechanisms are necessary to add hypermedia structures over data collections. If the structures are versioned then versioning mechanisms are needed also. Finally, navigation mechanisms are necessary to browse the hypermedia structures. In general, collaboration mechanisms are necessary in all working modes except for individual work.

Figure 1. Necessary hypermedia technology for the required work practices and cooperation modes.

To demonstrate the need for the mentioned work practices, cooperation modes, and hypermedia technology for scholarly work, we have included a small scenario. The scenario only exemplifies the usefulness of two of the sixteen combinations. We hope that the reader can see the relevance of the other fourteen combinations. These are left out due to space limitations.

We have identified important requirements for services and work practices in a digital library supporting scholarly work. The goal of HyTech is to support the three identified work practices that are especially important in a digital library for scholarly work (such as HyNIC). Currently, we have two types of hypermedia structuring and navigation services (associative and spatial). We are still only in the initial phases of development with the versioning service. The collaboration service is currently only partly developed. This means that we cannot yet support all the four cooperation modes that we envision.

The research conducted in the HyTech project aims to provide significant contributions to both the hypermedia and digital library fields. A major contribution for the hypermedia field is to advance the state of the art of hypermedia technology. Building on and extending the existing base of technology, a broader platform of hypermedia functionality will be made available for application developers. The field of digital libraries is in many ways still in its infancy. Though the potential of digital libraries is enormous, many important problems remain unsolved. The deployment of state-of-the-art hypermedia technology in the digital library setting will help to address some of these challenges and will also demonstrate the usefulness of this technology in an important real world application area, benefiting both the hypermedia and digital libraries fields.

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[3] HyNIC. 1999. HyNIC: ACM SIGWEB’s Digital Library Project. http://www.acm.org/sigweb/HyNIC.html

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[8] Wiil, U. K., and Leggett, J. J. 1997. Hyperform: A hypermedia system development environment. ACM Transactions on Information Systems, 15, 1, (Jan), 1-31.