In reaction to Norman's (1999) essay on misuse of the term affordance in human-computer interaction literature, this article is a concept paper affirming the importance of this powerful concept, reinforcing Norman's distinctions of terminology, and expanding on the usefulness of the concepts in terms of their application to interaction design and evaluation. We define and use four complementary types of affordance in the context of interaction design and evaluation: cognitive affordance, physical affordance, sensory affordance, and functional affordance. The terms cognitive affordance (Norman's perceived affordance) and physical affordance (Norman's real affordance) refer to parallel and equally important usability concepts for interaction design, to which sensory affordance plays a supporting role. We argue that the concept of physical affordance carries a mandatory component of utility or purposeful action (functional affordance). Finally, we provide guidelines to help designers think about how these four kinds of affordance work together naturally in contextualized HCI design or evaluation.

The current variety of alternative approaches to usability evaluation methods (UEMs) designed to assess and improve usability in software systems is offset by a general lack of understanding of the capabilities and limitations of each. Practitioners need to know which methods are more effective and in what ways and for what purposes. However, UEMs cannot be evaluated and compared reliably because of the lack of standard criteria for comparison. In this article, we present a practical discussion of factors, comparison criteria, and UEM performance measures useful in studies comparing UEMs. In demonstrating the importance of developing appropriate UEM evaluation criteria, we offer operational definitions and possible measures of UEM performance. We highlight specific challenges that researchers and practitioners face in comparing UEMs and provide a point of departure for further discussion and refinement of the principles and techniques used to approach UEM evaluation and comparison.

The current variety of alternative approaches to usability evaluation methods (UEMs) designed to assess and improve usability in software systems is offset by a general lack of understanding of the capabilities and limitations of each. Practitioners need to know which methods are more effective and in what ways and for what purposes. However, UEMs cannot be evaluated and compared reliably because of the lack of standard criteria for comparison. In this article, we present a practical discussion of factors, comparison criteria, and UEM performance measures useful in studies comparing UEMs. In demonstrating the importance of developing appropriate UEM evaluation criteria, we offer operational definitions and possible measures of UEM performance. We highlight specific challenges that researchers and practitioners face in comparing UEMs and provide a point of departure for further discussion and refinement of the principles and techniques used to approach UEM evaluation and comparison.

The design and construction of usable interactive systems requires a user-centered approach to system development. Such an approach requires tools and representations reflecting a behavioral view of the interface-a view centered on user activities and the system activities and states that the user can perceive. We present a model of these behavioral phenomena well suited for defining, extending, and analyzing behavioral representations. Our model is based on the timetree, a novel tree-based structure representing tasks, user actions, system activity, and system and interface state, all within a framework of branching sequential timelines. We introduce the timetree model by relating it to well-known interactive behaviors. We present a formal definition of timetrees and some of the operations they support, and we show some ways in which the model has contributed to our understanding of behavioral descriptions.

Although existing lab-based formative evaluation is frequently and effectively applied to improving usability of software user interfaces, it has limitations that have led to the concept of remote usability evaluation. Perhaps the most significant impetus for remote usability evaluation methods is the need for a project team to continue formative evaluation downstream, after deployment.The usual kinds of alpha and beta testing do not qualify as formative usability evaluation because they do not yield detailed data observed during usage and associated closely with specific task performance. Critical incident identification is arguably the single most important source of this kind of data. Consequently, we developed and evaluated a cost-effective remote usability evaluation method, based on real users self-reporting critical incidents encountered in real tasks performed in their normal working environments. Results show that users with only brief training can identify, report, and rate the severity level of their own critical incidents.

Article Free Access Share on Remote evaluation: the network as an extension of the usability laboratory Authors: H. Rex Hartson Department of Computer Science, Jonathan Kamler, Department of Forestry, Virginia Tech, Blacksburg, VA Department of Computer Science, Jonathan Kamler, Department of Forestry, Virginia Tech, Blacksburg, VAView Profile , José C. Castillo Department of Computer Science, Jonathan Kamler, Department of Forestry, Virginia Tech, Blacksburg, VA Department of Computer Science, Jonathan Kamler, Department of Forestry, Virginia Tech, Blacksburg, VAView Profile , John Kelso Department of Computer Science, Jonathan Kamler, Department of Forestry, Virginia Tech, Blacksburg, VA Department of Computer Science, Jonathan Kamler, Department of Forestry, Virginia Tech, Blacksburg, VAView Profile , Wayne C. Neale Eastman Kodak Company, 901 Elmgrove Road, Rochester, NY Eastman Kodak Company, 901 Elmgrove Road, Rochester, NYView Profile Authors Info & Claims CHI '96: Proceedings of the SIGCHI Conference on Human Factors in Computing SystemsApril 1996 Pages 228–235https://doi.org/10.1145/238386.238511Published:13 April 1996Publication History 105citation2,955DownloadsMetricsTotal Citations105Total Downloads2,955Last 12 Months229Last 6 weeks26 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my AlertsNew Citation Alert!Please log in to your account Save to BinderSave to BinderCreate a New BinderNameCancelCreateExport CitationPublisher SiteView all FormatsPDF

Article Free Access Share on Development and evaluation of a taxonomical model of behavioral representation techniques Authors: J. D. Chase Department of Computer Science, Virginia Tech, Blacksburg VA Department of Computer Science, Virginia Tech, Blacksburg VAView Profile , Robert S. Schulman Department of Statistics, Virginia Tech, Blacksburg VA Department of Statistics, Virginia Tech, Blacksburg VAView Profile , H. Rex Hartson Department of Computer Science, Virginia Tech, Blacksburg VA Department of Computer Science, Virginia Tech, Blacksburg VAView Profile , Deborah Hix Department of Computer Science, Virginia Tech, Blacksburg VA Department of Computer Science, Virginia Tech, Blacksburg VAView Profile Authors Info & Claims CHI '94: Proceedings of the SIGCHI Conference on Human Factors in Computing SystemsApril 1994 Pages 159–165https://doi.org/10.1145/191666.191730Online:24 April 1994Publication History 3citation406DownloadsMetricsTotal Citations3Total Downloads406Last 12 Months20Last 6 weeks8 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my AlertsNew Citation Alert!Please log in to your account Save to BinderSave to BinderCreate a New BinderNameCancelCreateExport CitationPublisher SiteeReaderPDF

Abstract

The need for communication among a multiplicity of cooperating roles in user interface development translates into the need for a common set of interface design representation techniques. The important difference between design of the interaction part of the interface and design of the interface software calls for representation techniques with a behavioral view - a view that focuses on user interaction rather than on the software. The User Action Notation (UAN) is a user- and task-oriented notation that describes physical (and other) behavior of the user and interface as they perform a task together. The primary abstraction of the UAN is a user task. The work reported here addresses the need to identify temporal relation-ships within user task descriptions and to express explicitly and precisely how designers view temporal relationships among those tasks. Drawing on simple temporal concepts such as events in time and preceding and overlapping of time intervals, we identify basic temporal relationships among tasks: sequence, waiting, repeated disjunction, order independence, interruptibility, one-way interleavability, mutual interleavability , and concurrency. The UAN temporal relations, through the notion of modal logic, offer an explicit and precise representation of the specific kinds of temporal behavior that can occur in asynchronous user interaction without the need to detail all cases that might result.

Some conventional approaches to interactive system development tend to force commitment to design detail without a means for visualizing the result until it is too late to make significant changes. Rapid prototyping and iterative system refinement, especially for the human interface, allow early observation of system behaviour and opportunities for refinement in response to user feedback. The role of rapid prototyping for evaluation of interface designs is set in the system development life-cycle. Advantages and pitfalls are weighed, and detailed examples are used to show the application of rapid prototyping in a real development project. Kinds of prototypes are classified according to how they can be used in the development process, and system development issues are presented. The future of rapid prototyping depends on solutions to technical problems that presently limit effectiveness of the technique in the context of present day software development environments.

Abstract The Dialogue Management Project at Virginia Tech is studying the poorly understood problem of human‐computer dialogue development. This problem often leads to low usability in human‐computer dialogues. The Dialogue Management Project approaches solutions to low usability in interfaces by addressing human‐computer dialogue development as an integral and equal part of the total system development process. This project consists of two rather distinct, but dependent, parts. One is development of concepts for dialogue management, and the other is implementation of a dialogue management system (DMS) to evaluate these concepts. The goal of this paper is to describe our approach to the development of two of these conceptual aspects and how we oriented those toward the needs of practical implementation. The two conceptual aspects are A structural, descriptive model of human‐computer interaction, and Techniques for representing both the behavioural (end‐user's) view and the constructional (developer's) view of dialogue. The approach to their development was a technology transfer process that was part of a two‐year university/industry research liaison between the Dialogue Management Project and IBM Federal Systems Division (FSD), now called Systems Integration Division. Part of this liaison was aimed at moving our research ideas and results into a real‐world dialogue development environment. Following presentation of the technical problems and solutions, the paper concludes with a discussion of results of our liaison and by raising and addressing some questions of mutual interest that arose during our co‐operative interaction.

Many existing interface representation techniques, especially those associated with UIMS, are constructional and focused on interface implementation, and therefore do not adequately support a user-centered focus. But it is in the behavioral domain of the user that interface designers and evaluators do their work . We are seeking to complement constructional methods by providing a tool-supported technique capable of specifying the behavioral aspects of an interactive system–the tasks and the actions a user performs to accomplish those tasks. In particular, this paper is a practical introduction to use of the User Action Notation (UAN), a task- and user-oriented notation for behavioral representation of asynchronous, direct manipulation interface designs. Interfaces are specified in UAN as a quasihierarchy of asynchronous tasks. At the lower levels, user actions are associated with feedback and system state changes. The notation makes use of visually onomatopoeic symbols and is simple enough to read with little instruction. UAN is being used by growing numbers of interface developers and researchers. In addition to its design role, current research is investigating how UAN can support production and maintenance of code and documentation.

A simple, task-oriented notation for describing user actions in asynchronous user interfaces is introduced. This User Action Notation (UAN) allows the easy association of actions with feedback and system state changes as part of a set of asynchronous interface design techniques, by avoiding the verbosity and potential vagueness of prose. Use within an actual design and implementation project showed the UAN to be expressive, concise, and highly readable because of its simplicity. The task- and user-oriented techniques are naturally asynchronous and a good match for object-oriented implementation. Levels of abstraction are readily applied to allow definition of primitive tasks for sharing and reusability and to allow hiding of details for chunking. The UAN provides a critical articulation point, bridging the gap between the task viewpoint of the behavioral domain and the event-driven nature of the object-oriented implementational domain. The potential for UAN task description analysis may address some of the difficulties in developing asynchronous interfaces.

The Author's Interactive Dialogue Environment (AIDE) of the Dialogue Management System is an integrated set of direct manipulation tools used by a dialogue author to design and implement human-computer interfaces without writing source code. This paper presents the conceptual dialogue transaction model upon which AIDE is based, describes AIDE, and illustrates how a dialogue author develops an interface using AIDE. A preliminary empirical evaluation of the use of AIDE versus the use of a programming language to implement an interface shows very encouraging results.

Abstract This paper brings together a formal predicate‐based model of protection and a relational approach to a protection database within the modular architecture of MULTISAFE. An implementation model is developed for the management of stored representations of authorization information. Classes of access decision dependency are reviewed, and protection policies, design decisions, and some implementation problems are discussed. Detailed examples are used to illustrate the use of this flexible and generalized approach to database security within the MULTISAFE system architecture.

This paper describes the configuration and intermodule communication of a MULTImodule system for supporting Secure Authorization with Full Enforcement (MULTISAFE) for database management. A modular architecture is described which provides secure, controlled access to shared data in a multiuser environment, with low performance penalties, even for complex protection policies. The primary mechanisms are structured and verifiable. The entire approach is immediately extendible to distributed protection of distributed data. The system includes a user and applications module (UAM), a data storage and retrieval module (SRM), and a protection and security module (PSM). The control of intermodule communication is based on a data abstraction approach, initially described in terms of function invocations. An implementation within a formal message system is then described. The discussion of function invocations begins with the single terminal case and extends to the multiterminal case. Some physical implementation aspects are also discussed, and some examples of message sequences are given.

As the complexity of human-computer interfaces increases, those who use these interfaces as well as those reponsible for their design have recognized an urgent need for substantive research in the human factors of software development [2], [5]. Because of the magnitude of the task of producing software for individual human-computer interfaces, appropriate tools are needed for defining and improving such interfaces, both in research and production environments. This paper describes the research being carried out to construct DMS (Dialogue Management System), which is a complete system for defining, modifying, executing, and metering human-computer dialogues.

Abstract Knowledge is of two kinds. We know a subject ourselves, or we know where we can find information upon it. And in such indexes, although small pricks to their subsequent volumes, there is seen the baby figure of the giant mass of things to come. Samuel Johnson, April 18, 1775, from Boswell's Life of Johnson, published 1791.

Today there is widespread application of digital control circuitry in a wide range of products. This paper describes a simulation system in which the designer of these control circuits can interact with his design ideas before they are implemented in hardware. The Digitial Control Simulation System (DCSS) is a digital design description language with a set of programs to generate and execute a simulation program. The main use of this system (with an appropriate hardware interface) is the testing of, and possibly on-line simulation of, the control of a system being designed and constructed.