Frank G. Halasz

The Dexter hypertext reference model

This paper presents the Dexter hypertext reference model. The Dexter model is an attempt to capture, both formally and informally, the important abstractions found in a wide range of existing and future hypertext systems. The goal of the model is to provide a principled basis for comparing systems as well as for developing interchange and interoperability standards. The model is divided into three layers. The storage layer describes the network of nodes and links that is the essence of hypertext. The runtime layer describes mechanisms supporting the user’s interaction with the hypertext. The within-component layer covers the content and structures within hypertext nodes. The focus of the model is on the storage layer as well as on the mechanisms of anchoring and presentation specification that form the interfaces between the storage layer and the within-component and runtime layers, respectively. The model is formalized in the specification language Z, a specification language based on set theory. The paper briefly discusses the issues involved in comparing the characteristics of existing systems against the model.

Liveboard: a large interactive display supporting group meetings, presentations, and remote collaboration

This paper describes the Liveboard, a large interactive display system. With nearly one million pixels and an accurate, multi-state, cordless pen, the Liveboard provides a basis for research on user interfaces for group meetings, presentations and remote collaboration. We describe the underlying hardware and software of the Liveboard, along with several software applications that have been developed. In describing the system, we point out the design rationale that was used to make various choices. We present the results of an informal survey of Liveboard users, and describe some of the improvements that have been made in response to user feedback. We conclude with several general observations about the use of large public interactive displays.

Notecards in a nutshell

NoteCards is an extensible environment designed to help people formulate, structure, compare, and manage ideas. NoteCards provides the user with a “semantic network” of electronic notecards interconnected by typed links. The system provides tools to organize, manage, and display the structure of the network, as well as a set of methods and protocols for creating programs to manipulate the information in the network. NoteCards is currently being used by more than 50 people engaged in idea processing tasks ranging from writing research papers through designing parts for photocopiers. In this paper we briefly describe NoteCards and the conceptualization of idea processing tasks that underlies its design. We then describe the NoteCards user community and several prototypical NoteCards applications. Finally, we discuss what we have learned about the systems strengths and weaknesses from our observations of the NoteCards user community.

Aquanet: a hypertext tool to hold your knowledge in place

Hypertext systems have traditionally focused on information management and presentation. In contrast, the Aquanet hypertext system described in this paper is designed to support knowledge structuring tasks. Aquanet is a browser-based tool that allows users to graphically represent information in order to explore its structure. In this paper, we discuss our motivations for developing Aquanet. We then describe the basic concepts underlying the tool and give an overview of the user interface. We close with some brief comments about our initial experiences with the tool in use and some of the directions we see the Aquanet research moving in the near future.

Analogy considered harmful

The computer is like a typewriter. The computer is like a filing cabinet. The computer is a personal servant ready to obey your every command. It is often claimed (e.g., Carroll and Thomas [3], Rumelhart and Norman [7]) that the best way to introduce a new user to a computer system is to draw an analogy between the computer and some situation familiar to the user. Given the analogy, the new user can draw upon his knowledge about the familiar situation in order to reason about the workings of the mysterious new computer system. For example, if the new user wants to understand about how the computer file system works, he need only think about how an office filing cabinet works and then carry over this same way of thinking to the computer file system.

Reflections on NoteCards: seven issues for the next generation of hypermedia systems

NoteCards is a general hypermedia environment designed to help people work with ideas. Its intended users are authors, designers, and other intellectual laborers engaged in analyzing information, designing artifacts, and generally processing ideas. The system provides these users with a variety of hypermedia-based tools for collecting, representing, managing, interrelating, and communicating ideas. This paper presents the NoteCards system as a foil against which to explore some of the major limitations of the current generation of hypermedia systems. In doing so, this paper highlights seven of the major issues that must be addressed in the next generation of hypermedia systems. These seven issues are: search and query, composite nodes, virtual structures, computational engines, versioning, collaborative work, and tailorability. For each of these issues, the papers describes the limitations inherent in NoteCards and the prospects for doing improving the situation in future systems.

Supporting collaboration in notecards

This paper describes a project underway to investigate computer support for collaboration. In particular, we focus on experience with and extensions to NoteCards, a hypertext-based idea structuring system. The forms of collaboration discussed include draft-passing, simultaneous sharing and online presentations. The requirement that mutual intelligibility be maintained between collaborators leads to the need for support of annotative and procedural as well as substantive activities.

Adaptability and Tailorability in NoteCards

NoteCards is an information structuring system developed in the Intelligent Systems Lab at Xerox PARC. A major design goal has been that NoteCards be an adaptable system, that is, tunable or customizable by users for particular applications and styles of use. In this paper, we describe four ways that a system can be adaptable: (1) it can have a flexible underlying conceptual model, (2) its behavior can be parametrized, (3) it can be integratable with other facilities, and (4) it can be tailorable, i.e. users themselves can add new functionality. We discuss the adaptability of NoteCards according to each of the above criteria. Finally, an example of large-scale tailoring in NoteCards is presented.

The role of hypertext for CSCW applications

Hypertext and CSCW are both growing fields of research and development that should converge by providing each other with complementary results. Features and concepts inherent to hypertext like the ability to create modules of information, combine them in a flexible way, reuse existing material, define views for different targets and user groups, and annotate multimedia material address many CSCW tool requirements. Furthermore, domains where hypertext already plays an important role (e.g., document preparation, idea management, design problem solving, decision making and argumentation, teaching and training) are or will soon become high priority topics for CSCW applications. There is no doubt that hypertext systems have to become multi-user systems and have to be extended by appropriate capabilities (e.g. shared screens, locking mechanisms in the hyperdocument base, versioning, knowledge-based components for monitoring access and changes by different users and reporting this on the basis of defined rules, etc.). On the other hand, CSCW is lacking a clear concept about which types of “document” structures and formats are needed as an appropriate communication medium for cooperation and collaboration.