This chapter describes in detail the Information Elicitation and Analysis Phase of the method. The phase comprises two design stages, namely the Extant Systems Analysis Stage and the Generalised Task Model Stage. The stages, described in the order of their application (see Figure 4-1), are concerned with the generation and analysis of background information to support subsequent derivation of a system design.

As indicated in Chapter Three, intermediate design processes, products and documentation schemes for each stage of the method are described as follows:

1. (a) an overview of the stage is provided prior to a detailed description;

2. (b) a block diagram summary of the stage is provided to highlight the sub-processes involved in transforming stage input(s) into one or more intermediate product(s);

3. (c) case-study illustrations of the products, processes and documentation schemes of the stage are provided where appropriate.

The Extant Systems Analysis (ESA) Stage

The main objective of the ESA Stage is to generate background information to assist the design of the target system at later stages of the method (see Figure 4–1 – the ESA Stage is highlighted by a box outlined in bold). To this end, extant systems are analysed to characterise current user needs and problems; existing function allocation between the user and device; the design features and rationale of existing user interfaces; etc.

The primary objective of this chapter is to characterise the problem addressed by MUSE, a structured human factors Method for Usability Engineering. To this end, existing problems of human factors contributions to system development are reviewed; namely, existing contributions are poorly timed and contextualised to the support required at different stages of the system design cycle. As a result, the relevance, format and granularity of human factors contributions are not optimal for effective uptake during design. By establishing the nature of the problems, promising solutions may then be assessed. Arguments supporting a structured analysis and design method, such as MUSE, are thus exposed.

General Problems of Human Factors Contribution to System Development

Recent developments in computer technology (e.g. the availability and affordability of personal computers and the rapid diversification in computer applications) have resulted in a shift from mainframes to personal computers. Today, such interactive computers have made significant inroads into both the workplace and the home. Consequently, the user base of computers has widened considerably.

The extended user base, together with market forces, highlighted the importance of designing computer applications that are appropriate in both functionality and usability. The success of Macintosh computers is an example (see also Shackel, 1985 and 1986b; CCTA (Draft) Report, 1988, Annex 1; Shuttleworth, 1987).

The objective of the present overview is to establish a conceptual foundation for a detailed stage-wise account of the method in Chapters Four to Six.

General Characteristics of the Human Factors Method

The primary focus of the method is on design specification because a literature survey indicated that current human factors contributions are well established at later stages of system development, e.g. human factors evaluation after design implementation. In contrast, human factors contributions to design specification are generally inadequate and implicit. Since the recruitment of human factors contributions is traditionally late, the discovery of design errors is also delayed. As a result, the required modifications are costly and difficult to implement (see Chapter One). Thus, greater emphasis is placed on ensuring human factors contributions to design specification. In this context, a participative followed by consultative design role for human factors contribution is envisaged at system specification and implementation respectively. During the latter stage, existing techniques for human factors evaluation may be recruited to support the method. An overview of the method follows.

The method is structured into three phases, each of which comprises a number of design stages (Figure 2-8 is reproduced overleaf for reference).

The development of graphical user interfaces for interactive applications is subject to a series of well-known problems which could be relevant of the domain of visual design. This typically includes the problem of placing aesthetically interaction objects (IO) according to principles applied in placement strategies. This paper first reviews the problem of IO placement and shows the rationale for the most significant placement strategies found today. It then tries to compare six such strategies along several dimensions and mathematical relationships with respect to three points of view: the designer's point of view, the human factors expert's point of view, and the user's point of view.

Keywords: arrangement, dimensioning, interaction object, localization, interaction object placement, placement strategy, visual design.

Introduction

The problem of placement concerns the spatial position of interaction objects (IO) such as edit box, radio button, list box, … with respect to visual elements in a screen layout. Effective placement can be achieved through a particular placement strategy involving a certain amount of visual techniques such as proximity, alignment, separate reference, centering, and conformity. For instance, Galitz suggests a placement strategy where IOs should be placed according to their nature:

In this paper, the placement is defined as the description of a composite IO (e.g. a form container widget) for displaying IOs to be placed relatively to one another. Composite IOs generally allow IOs to resize themselves as the composite resizes.

Personal computer users typically manage hundreds of directories and thousands of files with hierarchically structured file managers, plus archaic cluttered-desktop window managers, and iconic representations of applications. These users must deal with the annoying overhead of window housekeeping and the greater burden of mapping their organizational roles onto the unnecessarily rigid hierarchy. An alternate approach is presented, Personal Role Manager (PRM), to structure the screen layout and the interface tools to better match the multiple roles that individuals have in an organization. Each role has a vision statement, schedule, hierarchy of tasks, set of people, and collection of documents.

Keywords: personal role manager, desktop metaphor, graphic user interface, coordination, computer-supported cooperative work (CSCW).

Introduction

The transition from the first generation command line interfaces (such as DOS 3 or UNIX) to second generation point-and-click graphical user interfaces (GUIs) was accompanied by an important metaphorical shift. The older systems required users to understand computerdomain concepts such as executable binary software (the .EXE or .COM files), file naming rules, and hierarchical directories. The designers of second generation GUIs presented users with more meaningful metaphors and supported direct manipulation interactions (Shneiderman, 1982). The graphical user interface offered a desktop with applications represented as icons, documents organized into folders, and even a trashcan as an affordance for the delete action. This visual representation of the world of action made objects and actions visible, permitted rapid, incremental and reversible actions, and emphasized pointing and clicking instead of keyboarding.

The current third generation approach emphasizes a “docu-centric” design (Microsoft's Object Linking and Embedding or Apple's OpenDoc Architecture), unified suites of software, and “information at your fingertips” through hypertext linking.

This volume contains the full papers and invited papers from the 1994 conference of the British HCI Group (a specialist group of the British Computer Society). It is a partial record of a more extensive conference that includes tutorials, panels, short papers, posters and demonstrations.

Human-Computer Interaction has been consolidating over the last few years. As a result, many recent conferences have tended to be bland, without really high points or really low points. The invited papers are forward looking and avoid blandness in that way. There are, however, many forward looking full papers. Moreover, the 1994 conference will be remembered as one that moved HCI forward in some areas, rather than just documented its current state within the established areas.

Proceedings Structure

The proceedings begin with the invited papers. This apart, the usual compromises of programme structure have not been carried forward into these proceedings. The full papers in this volume have been reorganised into broad topics. As ever in HCI, these topics are not disjoint and some papers could have easily have gone in one section as another. Readers interested in specific topics are thus advised to read through the full contents to avoid missing papers that may be of interest to them.

The second group of papers covers all stages of interactive systems development (properly iterated of course) from requirements capture and specification, through to evaluation. There are also papers on specific design issues, including application areas such as computer-assisted learning.

The third group of papers is the largest, and covers design knowledge at all levels of abstraction in interactive systems, from low level presentation to high level metaphors.

The embodiment of computers in desktop workstations has had a tremendous impact on the field of HCI. Now that mice and graphics displays are everywhere, the workstation defines the frontier between the computer world and the real world. We spend a lot of time and energy transferring information between those two worlds. This could be reduced by better integrating the real world with the computer world. This article describes two approaches to this integration: Mediaspaces, which allow people to communicate through an audio, video and computer environment, and Augmented Reality, which adds computational power to real world objects. The argument is made that the success of these approaches lies in their ability to build on fundamental human skills, namely the ability to communicate with other people and the ability to interact with objects in the real world.

Keywords: mediaspace, augmented reality, multimedia, video, virtual reality, paper interface, gesture input, metaphor, paradigm.

Introduction

Over the last decade, computers have evolved from mainframes to networks of personal computers and workstations. The range of users and uses of computers has expanded dramatically. Today, a computer is perceived more as an appliance than as a ‘machine’. A key aspect of this evolution has been, and still is, the development of the field of Human-Computer Interaction. HCI has complemented, and sometimes driven, the evolution of the technology to make computer systems easier to use by a wider variety of users in a larger number of contexts.

As most researchers in HCI know, this picture is a bit idyllic and much still needs to be done to improve the scope and usability of computers.

Automated macro systems which apply re-use to a user's input are a possible solution to the problems of customising an interactive system to the needs of the user. More useful than simple re-use would be a system that makes use of general patterns in users' behaviour and encapsulates this knowledge for application in similar, yet unfamiliar, circumstances. This process we term generalisation. This paper outlines some issues involved in controlling generalisation and the presentation and interaction with these macros, and specifies applicable heuristics. Finally the architecture for building an adaptive agent to perform the whole process is presented, with an example prototype operating on UNIX command-line interaction.

Keywords: adaptive interfaces, interface customisation, interface transformation, command reuse, agent modelling, initiative.

Introduction

One example of demonstrational interfaces (Myers, 1991) — automated macro creation — has been shown to be a promising area for adaptive system research previously by Greenberg (1990) and Crow & Smith (1992). Crow & Smith have extended the simple re-use of previous command entries (the history/tool-based systems of Greenberg) from a single line to an inferred macro. Macros are a concept that users are already familiar with for automation.

Re-use, however, is limited to situations corresponding exactly to those which have occurred before. Whilst it has been shown that these situations happen reasonably frequently (Greenberg & Witten, 1993a; Greenberg & Witten, 1993b) for single line re-use (a result which has not been investigated for multi-line re-use), both single-line and multi-line macro re-use break down in situations which differ slightly from the original. In both cases the re-use system is of no help.

We present a new visual programming language and environment that serves as a form of feedback and representation in a Programming by Demonstration system. The language differs from existing visual languages because it explicitly represents data objects and implicitly represents operations by changes in data objects. The system was designed to provide non-programmers with programming support for common, repetitive tasks and incorporates some principles of cognition to assist these users in learning to use it. With this in mind, we analyzed the language and its editor along cognitive dimensions. The assessment provided insight into both strengths and weaknesses of the system, prompting a number of design changes. This demonstrates how useful such an analysis can be.

Keywords: cognitive dimensions, end-user programming, programming by demonstration, visual language, visual shell, Pursuit.

Introduction

A visual shell (or desktop) is a direct manipulation interface to a file system. Examples include the Apple Macintosh desktop and the Xerox Star. Although such systems are easy to use, most do not support end-user programming. Pursuit is a visual shell aimed at providing programming capabilities in a way that is consistent with the direct manipulation paradigm.

To enable users to construct programs, Pursuit contains a Programming by Demonstration (PBD) system (Cypher, 1993). In a PBD system, users execute actions on real data and the underlying system attempts to construct a program (Myers, 1991). Such systems have limitations: feedback is often difficult to understand, disruptive or non-existent; and programs often have no representation for users to examine or edit. Pursuit addresses these problems by presenting the evolving program in a visual language while it is being constructed.

Synchronisation is a key issue for collaborative user interfaces. An examination of current approaches, in particular the concept WYSIVVIS and the use of Video as a communication medium, highlights a number of issues in this area including lack of a common spatial frame of reference, lack of appropriate embodiment of users and inflexible and rigid communication channels between users. The paper then proposes a new framework for designing collaborative user interfaces which addresses these issues. This framework is based on the notion of a common spatial frame within which embodied users are free to move autonomously, being casually aware of each other's activities. Embodiment is considered in terms of both individual viewpoints and actionpoints (e.g. telepointers) within the display space. We propose that, in many cases, synchronisation of the spatial frame is necessary but synchronisation of viewpoints and actionpoints may actually inhibit collaboration. We finish by describing some prototype systems which provide one (of possibly many) examples of how our framework might be employed; in this case to create shared cooperative virtual environments.

Keywords: synchronisation, video, WYSIWIS, virtual reality, multi-user interface, computer-supported cooperative work (CSCW).

Introduction

Collaborative user interfaces, particularly shared workspaces, have been the focus of considerable research effort in recent years. Resulting systems include multi-user editors and drawing tools (Ellis, Gibbs & Rein, 1991; Foster & Stefik, 1986; Greenberg & Bohnet, 1991), shared screen systems and more specialised design surfaces (Ishii & Kobayashi, 1992). There has also been a growth in the use of multi-media technology to support communication and awareness between the users of such systems including conferencing systems (Sarin & Greif, 1985) and media-spaces (Gaver et al., 1992; Root, 1988).

The paper illustrates the use of structured notations to support the specification of various aspects of a system design; such as organisational hierarchies, conceptual level tasks, domain semantics, human-computer interactions, etc. In contrast with formal or algebraic notations, graphical structured notations are communicated to users more easily. Thus, user feedback elicitation and design validation would be supported better throughout system development. It is expected that the structured notations illustrated in the paper, could be used more widely for two reasons; namely they support more specific task specifications, and have now been incorporated into a structured human factors method. In addition, off-the-shelf computer-based support for the notation is emerging, e.g. PDFTM.

Keywords: graphical structured notations, human factors specifications, structured human factors method.

General Requirements of a Notation for Human Factors Specification

Generally, an appropriate human factors notation should fulfil two pre-requisites, namely it should rectify the inadequacies of existing human factors notations, and accommodate additional specification demands arising from wider human factors involvement in system development. In particular, a notation should satisfy the following requirements:

1. a. Specificity. Current human factors specifications have been criticised for being insufficiently specific. This situation is aggravated further by the increasingly complex and sophisticated systems being designed. In response to these demands, human factors methods should be enhanced to include more powerful notations to support tighter design specification. For instance, in safety critical system development, task specifications should be detailed enough to support design simulation, workload assessment and probabilistic human reliability assessment. Thus, Brooks' (1991) emphasis on task specifications that reveal the hierarchical structure and operational control of the user's task, is especially pertinent. Hence, notational constructs should satisfy the demands of such design specifications;

2. […]