This paper presents the results of a study conducted at Georgia Institute of Technology that captured client-side user events of NCSA's XMosaic. Actual user behavior, as determined from clientside log file analysis, supplemented our understanding of user navigation strategies as well as provided real interface usage data. Log file analysis also yielded design and usability suggestions for WWW pages, sites and browsers. The methodology of the study and findings are discussed along with future research directions. Keywords Hypertext Navigation, Log Files, User Modeling Introduction With the prolific growth of the World-Wide Web (WWW) [Berners-Lee et.al, 1992] in the past year there has been an increased demand for an understanding of the WWW audience. Several studies exist that determine demographics and some behavioral characteristics of WWW users via selfselection [Pitkow and Recker 1994a & 1994b]. Though highly informative, such studies only provide high level trends in Web use (e...

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Almost as long as there have been user interfaces, there have been special software systems and tools to help design and implement the user interface software. Many of these tools have demonstrated significant productivity gains for programmers, and have become important commercial products. Others have proven less successful at supporting the kinds of user interfaces people want to build. This article discusses the different kinds of user interface software tools, and investigates why some approaches have worked and others have not. Many examples of commercial and research systems are included. Finally, current research directions and open issues in the field are discussed.

This paper introduces the notion of “universal interaction,” allowing a device to adapt its functionality to exploit services it discovers as it moves into a new environment. Users wish to invoke services — such as controlling the lights, printing locally, or reconfiguring the location of DNS servers — from their mobile devices. But aprioristandardization of interfaces and methods for service invocation is infeasible. Thus,the challenge is to develop a new service architecture that supports heterogeneity in client devices and controlled objects, and which makes minimal assumptions about standard interfaces and control protocols. There are five components to a comprehensive solution to this problem: 1) allowing device mobility, 2) augmenting controllable objects to make them network-accessible, 3) building an underlying discovery architecture, 4) mapping between exported object interfaces and client device controls, and 5) building complex behaviors from underlying composable objects. We motivate the need for these components by using an example scenario to derive the design requirements for our mobile services architecture. We then present a prototype implementation of elements of the architecture and some example services using it, including controls to audio/visual equipment, extensible mapping, server autoconfiguration, location tracking, and local printer access.

This article summarizes the results of the BARWAN project, which focused on enabling truly useful mobile networking across an extremely wide variety of real-world networks and mobile devices. We present the overall architecture, summarize key results, and discuss four broad lessons learned along the way. The architecture enables seamless roaming in a single logical overlay network composed of many heterogeneous (mostly wireless) physical networks, and provides significantly better TCP performance for these networks. It also provides complex scalable and highly available services to enable powerful capabilities across a very wide range of mobile devices, and mechanisms for automated discovery and configuration of localized services. Four broad themes arose from the project: 1) the power of dynamic adaptation as a generic solution to heterogeneity, 2) the importance of cross-layer information, such as the exploitation of TCP semantics in the link layer, 3) the use of agents in the infrastructure to enable new abilities and to hide new problems from legacy servers and protocol stacks, and 4) the importance of soft state for such agents for simplicity, ease of fault recovery, and scalability.

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 ...

Because of its promise of natural interaction, recognition is coming into its own as a mainstream technology for use with computers. Both commercial and research applications are beginning to use it extensively. However the errors made by recognizers can be quite costly, and this is increasingly becoming a focus for researchers. We present a survey of existing error correction techniques in the user interface. These mediation techniques most commonly fall into one of two strategies, repetition and choice. Based on the needs uncovered by this survey, we have developed OOPS, a toolkit that supports resolution of input ambiguity through mediation. This paper describes four new interaction techniques built using OOPS, and the toolkit mechanisms required to build them. These interaction techniques each address problems not directly handled by standard approaches to mediation, and can all be re-used in a variety of settings.

One method for user interface analysis that has proven successful is formal interface analysis, such as GOMSbased analysis. Such methods are often criticized for being difficult to learn, or at the very least an additional burden for the system designer. However, if the process of constructing and using formal models could be automated as part of the interface design environment, such models could be of even greater value. This paper describes an early version of such a system, called USAGE (the UIDE System for semi-Automated GOMS Evaluation). Given the application model necessary to drive the UIDE system, USAGE generates an NGOMSL model of the interface which can be “run ” on a typical set of user tasks and provide execution and learning time estimates.

This paper presents a complete model-based approach to the building of presentation for a business oriented highly interactive application. This approach is considered complete in the sense that it supports a continuum from task analysis to a first prototype without disruption. The main steps involved in the proposed methodology include a task analysis performed as a hierarchical decomposition of the interactive task into sub-tasks, a specification of the functional requirements and its integration with task analysis results, a writing of an activity chaining graph which graphically depicts the information and function flow within the task, the selection of an interaction style, the definition of presentation units, the selection of abstract interaction objects, their transformation into concrete objects to be placed before generating a first prototype. The described methodology not only consists of the definition of these steps, but also shows how computer-aided tools can automatically generate the presentation of such an interface.

this paper, I review the history of HCI as steps toward a science of design. My touchstone is Simon's (1969) provocative book he Sciences of the Artificial. The book pre-dates HCI, and many of its specific characterizations and claims about design are no longer authoritative (see Ehn, 1988). Nevertheless, two of Simon's themes echo through the history of HCI, and still provide guidance for charting its continuing development