Towards user interfaces for all: some critical issues

Symbiosis of Human and Artifact Y. Anzai, K. Ogawa and H. Mori (Editors) © 1995 Elsevier Science B.V. All rights reserved.

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Towards User Interfaces for All: Some Critical Issues C. Stephanidis Institute of Computer Science, Foundation for Research and Technology - Hellas, Science and Technology Park of Crete, P.O. Box 1385, GR-71110 Heraklion, Crete, Greece

1. INTRODUCTION Mainstream research and development in the HCI field has mainly addressed the needs of the "average" able user [1]; only in recent years, have some efforts been directed towards exploiting such technological outcomes, particularly in the Assistive Technology field. It is argued that these efforts have been carried out, until now, in a fragmented way, often following ad hoc procedures and addressing specific problems of specific users or user groups. The most common approach has been to adapt commercially available software products, or to develop special purpose applications in order to enable accessibility by a target user category. A representative example of adaptation oriented approaches are the so called screen readers for enabling partial accessibility of graphical User Interfaces by blind users. However, more recent approaches have demonstrated the technical feasibility of providing User Interface development systems which, at design time, take into consideration the access requirements of both able and disabled users [2], [3]. The evident speed of technological progress in the HCI field necessitates a more holistic approach towards solving accessibility issues for people with disabilities, since the application of adaptation methods becomes inappropriate due to: (i) the high cost for producing customised case-specific solutions for the different application domains, interaction technologies/environments, and target user groups, and (ii) technical problems, since for the vast majority of emerging interaction technologies, the application of adaptation oriented approaches may become practically impossible or meaningless (for instance, consider the problem of automatically reproducing, a Virtual Reality based information cyberspace in a non-visual form). It is argued that, by following a proactive approach (i.e. addressing accessibility issues at design time), it is possible to ensure that forthcoming technologies are made accessible to all. Moreover, it is claimed that the population at large stands to gain additional benefits from such proactive considerations of emerging technological advancements (i.e. there is added

value).

2. TOWARDS USER INTERFACES FOR ALL: THE CONCEPT OF UNIFIED USER INTERFACES The concept of User Interfaces for all is proposed, following the concept of design for all, as the vehicle to efficiently and effectively address the numerous and diverse accessibility

138 problems. The underlying principle is to ensure ac=essibility at design time and to meet the individual needs, abilities and preferences of the user population at large, including disabled and elderly people. Currently, there are no development tools to practically support the construction of User Interfaces for all. The present situation shows that the vast majority of software firms have adopted mainstream development approaches (which do not address the needs of disabled people), since the investment cost to provide accessibility for all is considered unacceptable, due to the lack of appropriate tools. It is believed that, if tool developers are provided with the necessary technological methods to build such tools in accordance with the "User Interfaces for all" principle, then software firms will be able to employ these tools in developing software products accessible to all. Using existing tools one needs to develop dedicated User Interfaces for each different target user (group). Moreover, the pluralism of available graphical environments (i.e. platforms) and operating systems increases the complexity of the problem and the already high development cost. The concept of unified User Interface development is proposed with the objective of supporting platform independence and target user-profile independence. Only a "core" of the User Interface will need to be developed, while the platform-specific and user-specific interface properties can be automatically handled by the proposed new tools [3]. Thus, instead of requiring several dedicated interface implementations, only a single (shared) implementation is necessary. The proposed tools can automatically manage the platform specific issues and adapt the resulting dialogue to the needs of the particular target user (group). We define as a unified User Interface, the outcome of unified User Interface Development. It is argued that, at present, unified User Interfaces are the most efficient approach to achieve the goal of User Interfaces for all. development ~!!~unification dimension ~i~i dimension

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The concept of unified User Interfaces is illustrated in Figure 1 [3]. Different user groups may require different interaction metaphors. Various implementations for a particular interaction metaphor may be provided. The requirement is that a unified User Interface is

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independent of the various metaphors, platforms and target user (group) profile (i.e. the unification dimension). In order to practically achieve the goal of User Interfaces for all, it is necessary to provide appropriate tools for supporting the development cycle of unified User Interfaces. Traditionally, user interface development environments have provided little support during the design phase of a user interface. This is partially attributed to the complexity associated with the modelling of design elements, but also due to the focus upon development and implementation. Modelling of user interface design components involves the consolidation of lexical, syntactic and semantic details of a user interface into a sufficiently expressive representation of reusable elements. This should aim to facilitate, amongst other things, appropriate dialogue sequencing, reasoning, selection and decisions on maximally preferred Input/Output devices and interaction techniques, as well as media allocation. The complexity that is usually encountered when modelling design elements of user interfaces is largely attributed to the incomplete knowledge about users, their preferences and attitudes, their mental models, as well as scenarios of use and cognitive representations. This is further complicated when considering user groups which require alternative access technology, either due to situational constraints, or to the lack of functional ability; one such category of users is people with disabilities. Unavailability of data depicting human performance analysis and human factors studies for disabled computer users, in conjunction with the lack of information and tools to facilitate rational selection of optimal device configurations, has led to nonsystematic, costly and time consuming user interface development for such computer users. Consequently, much still depends on intuition as existing user interface development environments have not, as yet, succeeded to empower user interface designers with appropriate high-level tools and design assistance. Semantic Level

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USERC Figure 2. Levels of adaptability in User Interface design. Towards this end, unified interface development offers a plausible and forthcoming solution, as it addresses the issue of coupling user interface development systems with design assistants to facilitate "unification" of user interface elements. Tools to empower designers and support unified interface design should, ideally, handle the wide range of issues related to the lexical, syntactic and semantic levels of user interface design (see Figure 2). One important issue that occurs on all three levels is user adaptability: at the semantic level of the user interface, adaptability involves the adaptation of the information content that the user

140 interface communicates; at the syntactic level, adaptability involves the determination of appropriate task structuring and dialogue sequencing. Finally, lexical adaptability is concerned with the encapsulation of interactive properties of the user interface and the ways in which these are communicated to the user (i.e. Input/Output devices, interaction techniques, etc). At all three levels, tools are required to provide support in determining the corresponding adaptable constituents, so as to allow the development and implementation of a user interface, according to the target user abilities, requirements and preferences.

3. D E V E L O P M E N T P L A T F O R M FOR UNIFIED USER INTERFACES

In the context of the ACCESS Project TP 1001 of the TIDE Programme of the European Commission, a development platform is being built which provides an integrated framework for efficiently supporting the design and implementation of unified User Interfaces. The main characteristics of this framework are: (i) Platform independence. The pluralism of platforms and graphical environments (e.g. MS-WINDOWS TM, X WINDOWING SYSTEM toolkits) implies the need of versatility of tools so that different environments can be easily managed. (ii) Metaphor independence. The interaction metaphor is tightly coupled with the characteristics of the target user group; different user groups may require a different metaphor of interaction. (iii) User adaptability. ,The resulting User Interfaces should be adaptable to the individual user needs, abilities and preferences. User modelling techniques are introduced for this purpose. (iv) Unified interface specification. The cost of implementing User Interfaces for all may prove particularly high, without proper techno-economic considerations; one of the benefits of the proposed framework is that it supports specification instead of

implementation. Figure 3 illustrates the framework of the development process for constructing unified User Interfaces. In order to efficiently support the implementation of unified User Interfaces, the framework provides a high-level 4th generation language for User Interface specification (called G-DISPEC), and a tool (called I-GET) that automatically generates the implementation from such high-level specifications. The G-DISPEC language and the I-GET tool constitute a novel User Interface Management System for unified User Interface development. Additionally, another tool has been developed, called PIM, which enables the generation of platform independent toolkits (i.e. programming libraries) for unified interface implementation. The resulting interface implementations, either those automatically generated by the I-GET tool, or those explicitly programmed via a toolkit generated by the PIM tool, can run on different target platforms (see Figure 3), which may correspond to particular interaction metaphors (e.g. DeskTop or Rooms [4]). The adaptability of the User Interface to the specific needs, abilities and preferences of the target user group is achieved at design time by means of a User Modelling Tool (USE-IT) [5]. This tool is part of the framework and takes the appropriate decisions regarding the lexical characteristics of the dialogue, based on: (a) knowledge about the user characteristics, abilities and preferences, and (b) knowledge about the structure of the lexical level characteristics with respect to the various target user groups (i.e. interaction objects, interaction techniques, devices, etc). It should be mentioned that unified User Interfaces, which are developed by utilising the tools of the proposed framework, automatically inquire the adaptability decisions generated by the USE-IT tool, and apply these decisions during user-computer interaction.

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4. S U M M A R Y A N D C O N C L U S I O N S

The evolution of User Interface Software and Technology has resulted in a plethora of novel developments and has given rise to the potential for supporting a new generation of User Interfaces. However, the mainstream of research and development has focused on the needs of the "average" able user, without taking into account the requirements of disabled and

142 elderly people. On the other hand, with the advent of new interaction technologies and methods, the development of User Interfaces requires increasingly more resources; consequently, the approach of "catching-up" with technological progress, for the benefit of disabled and elderly people, based on adaptations and customised solutions, becomes progressively less viable. Tools are needed which will support the development of "User Interfaces for all", through efficient and effective development procedures. In the context of the ACCESS project (TP 1001) of the TIDE Programme of the European Commission, such tools are being developed. The underlying concept is to support unified development of User Interfaces, appropriate for the various target user groups; such an approach eliminates the need for separate developments for each target user group, thus reducing the development cost. Moreover, the employment of high-level specification methods (i.e. 4th generation languages) through which implementation turns into specification, considerably reduces the overall development time and cost. The key issues for such unified development are: user adaptability, metaphor independence and platform independence. The User Interfaces produced through the unified development process are called unified User Interfaces and we argue that, at present, they are the most efficient approach to reach the objective of User Interfaces for all.

ACKNOWLEDGEMENTS Part of this R&D work is being carried out in the context of the ACCESS (TP1001) Project funded by the TIDE Programme of the Commission of the European Union (DG XIII). The partners of the ACCESS consortium are: IROE-CNR, Italy; Institute of Computer Science-FORTH, Greece; University of Athens, Greece; RNIB, U.K.; University of Hertfordshire, U.K.; SELECO, Italy; MA Systems & Control, U.K.; Hereward College, U.K.; National R&D Centre of Welfare and Health, Finland; VTI', Finland; PIKOMED, Finland.

REFERENCES

1. C. Stephanidis and M. Sfyrakis, Current Trends in Man-Machine Interfaces: Potential impact on People with Special Needs, in P. Roe (ed.), Telecommunications for All: Are you Reaching All your Customers?, to be published by the Commission of the European Union in the framework of the COST 219 Programme, Brussels, Belgium, 1995. 2. A. Savidis, and C. Stephanidis, Developing Dual User Interfaces for Integrating Blind and Sighted Users: the HOMER UIMS, Paper to appear in the Proceedings of the CHI' 95 Conference on Human Factors in Computing Systems, Denver, Colorado, May 7-11, 1995. 3. C. Stephanidis, A. Savidis and D. Akoumianakis, Tools for User Interfaces for All, to appear in the Proceedings of the 2nd TIDE Congress, La Villette, Paris, April 26-28, 1995. 4. A. Savidis and C. Stephanidis, Building non-visual interaction through the development of the Rooms metaphor, Short paper to appear in the Companion of the CHI' 95 Conference on Human Factors in Computing Systems, Denver, Colorado, May 7-11, 1995. 5. D. Akoumianakis and C. Stephanidis, User modelling for adaptable interface design, to appear in the proceeding of the HCI International '95 Conference on Human-Computer Interaction, Tokyo, Japan, July 9-14, 1995.