This article summarizes the historical development of major advances in humancomputer interaction technology, emphasizing the pivotal role of university research in the advancement of the field.

One of the recent trends in computer input is to utilize users' natural bimanual motor skills. This paper further explores the potential benefits of such two-handed input. We have observed that bimanual manipulation may bring two types of advantages to human-computer interaction: manual and cognitive. Manual benefits come from increased time-motion efficiency, due to the twice as many degrees of freedom simultaneously available to the user. Cognitive benefits arise as a result of reducing the load of mentally composing and visualizing the task at an unnaturally low level imposed by traditional unimanual techniques. Area sweeping was selected as our experimental task. It is representative of what one encounters, for example, when sweeping out the bounding box surrounding a set of objects in a graphics program. Such tasks can not be modelled by Fitts' Law alone (Fitts, 1954) and have not been previously studied in the literature. In our experiments, two bimanual techniques were compared with the conventional one-handed GUI approach. Both bimanual techniques employed the two-handed "stretchy" technique first demonstrated by Krueger (1983). We also incorporated the "Toolglass" technique introduced by Bier, Stone, Pier, Buxton and DeRose (1993). Overall, the bimanual techniques resulted in significantly faster performance than the status quo one-handed technique, and these benefits increased with the difficulty of mentally visualizing the task, supporting our bimanual cognitive advantage hypothesis. There was no significant difference between the two bimanual techniques. This study makes two types of contributions to the literature. First, practically we studied yet another class of transaction where significant benefits can be realized by applying bimanual techniques. Furth...

This paper examines the usability of the hypertext navigation facilities provided by World Wide Web client applications. A notation is defined to represent the user's navigational acts and the resultant system states. The notation is used to report potential, or `theoretical,' problems in the models of navigation supported by three web client applications. A usability study confirms that these problems emerge in actual use, and demonstrates that incorrect user models of the clients' facilities are common. A usability analysis identifies inadequacies in the clients' interfaces. Motivated by the analysis of usability problems, we propose extensions to the design of WWW client applications. These proposals are demonstrated by our system WebNetwhich uses dynamic graphical overview diagrams to extend the navigational facilities of conventional World Wide Web client applications. Related work on graphical overview diagrams for web navigation is reviewed. 1 Introduction The small...

Utilising adaptive interface techniques in the design of systems introduces certain risks. An adaptive interface is not static, but will actively adapt to the perceived needs of the user. Unless carefully designed, these changes may lead to an unpredictable, obscure and uncontrollable interface. Therefore the design of adaptive interfaces must ensure that users can inspect the adaptivity mechanisms, and control their results. One way to do this is to rely on the user's understanding of the application and the domain, and relate the adaptivity mechanisms to domainspecific concepts. We present an example of an adaptive hypertext help system POP, which is being built according to these principles, and discuss the design considerations and empirical findings that lead to this design.

Document preparation systems that are oriented to an author's preparation of printed material must permit the flexible specification, modification, and reuse of the contents of the document. Interactive document preparation systems commonly have incorporated simple representations--an unconstrained linear list of document objects in the 'What You See Is What You Get' (WYSIWYG) systems. Recent research projects have been directed at the interactive manipulation of richer tree-oriented representations in which object relationships are constrained through grammatical specification. The advantage of such representations is the increased flexibility that they provide in the reusability of the document and its components and the more powerful user command that they permit.

A user interface software tool helps developers design and implement the user interface. Research on past tools has had enormous impact on today's developers---virtually all applications today were built using some form of user interface tool. In this paper, we consider cases of both success and failure in past user interface tools. From these cases we extract a set of themes which can serve as lessons for future work. Using these themes, past tools can be characterized by what aspects of the user interface they addressed, their threshold and ceiling, what path of least resistance they offer, how predictable they are to use, and whether they addressed a target that became irrelevant. We believe the lessons of these past themes are particularly important now, because increasingly rapid technological changes are likely to significantly change user interfaces. We are at the dawn of an era where user interfaces are about to break out of the "desktop" box where they have been stuck for the ...

Cultures deal with their environments by adapting to them and simultaneously changing them. This is particularly true for technological cultures, such as the dynamic culture of computer users. To date, the ability to change computing environments in non-trivial ways has been dependent upon the skill of programming. Because this skill has been hard to acquire, most computer users must adapt to computing environments created by a small number of programmers. In response to the scarcity of programming ability, the computer science community has concentrated on producing general-purpose tools that cover wide spectrums of applications. As a result, contemporary programming languages largely ignore the intricacies arising from complex interactions between different people solving concrete problems in specific domains. This dissertation describes Agentsheets, a substrate for building domain-oriented, visual, dynamic programming environments that do not require traditional programming skills. It discusses how Agentsheets supports the relationship among people, tools, and problems in the context of four central themes: (1) Agentsheets features a versatile construction paradigm to build dynamic, visual environments for a wide range of problem domains such as art, artificial life, distributed artificial intelligence, education, environmental design, and

To facilitate the sharing of information using modern communication networks, users must be able to decide on a privacy policy---what information to conceal, what to reveal, and to whom. We describe the evolution of privacy interfaces---the user interfaces for specifying privacy policies ---in COLLABCLIO, a system for sharing web browsing histories. Our experience has shown us that privacy policies ought to be treated as first-class objects: policy objects should have an intensional representation, and privacy interfaces should support direct manipulation of these objects. We also show how these conclusions apply to a variety of domains such as file systems, email, and telephony. Keywords Privacy, user interfaces, direct manipulation, WWW, information retrieval, intensional/extensional set representations. INTRODUCTION It is commonplace that modern communication networks should support the sharing of information while protecting people's privacy. To this end networks provide mech...

The task of organizing information is typically performed either by physically manipulating note cards or sticky notes or by arranging icons on a computer with a graphical user interface. We present a new tangible interface platform for manipulating discrete pieces of abstract information, which attempts to combine the benefits of each of these two alternatives into a single system. We developed interaction techniques and an example application for organizing conference papers. We assessed the effectiveness of our system by experimentally comparing it to both graphical and paper interfaces. The results suggest that our tangible interface can provide a more effective means of organizing, grouping, and manipulating data than either physical operations or graphical computer interaction alone.

OdeView is the graphical front end for Ode, an object-oriented database system and environment. Ode's data model supports data encapsulation, type inheritance, and complex objects. OdeView provides facilities for examining the database schema (i.e., the object type or class hierarchy), examining class definitions, browsing objects, following chains of references starting from an object, synchronized browsing, displaying selected portions of objects (projection), and retrieving objects with specific characteristics (selection). OdeView does not need to know about the internals of Ode objects. Consequently, the internals of specific classes are not hardwired into OdeView and new classes can be added to the Ode database without requiring any changes to or recompilation of OdeView. Just as OdeView does not know about the object internals, class functions (methods) for displaying objects are written without knowing about the specifics of the windowing software used by OdeView or the graphi...