Making Model-Based UI Design Practical:
Usable and Open Methods and Tools
Hallvard Trætteberg
Norwegian University of Science andTechnology Sem Sællandsv. 7 7491 Trondheim, Norway
+47 73593443
[email protected]
Pedro J. Molina
CARE Technologies S.A.Pda. Madrigueres, 44. 03700 Denia, Spain
+34 966 435555
[email protected]
Nuno J. Nunes
University of Madeira Dep. Matemática e EngenhariasCampus da Penteada 9000-390 Funchal, Portugal
+351 291 705150
[email protected]
ABSTRACT
Model-based IU is an established discipline. However, it has not been adopted in the software industry with the initial expected success, and it has been kept in the meanwhile in the academia. The main aim of this workshop is to analyze the current problems with model-based UI design approaches and envision the main characteristics and challenges to solve in the next generation of model-based UI tools.
Categories and Subject Descriptors
D.2 [SOFTWARE ENGINEERING]: Design Tools and Techniques – user interfaces, object-oriented design methods. H.1 [MODELS AND PRINCIPLES]: User/Machine Systems.
General Terms
Design, Experimentation, Standardization, Languages.
Keywords
Model-Based User Interface Design, Methods, Tool Support, Industrial Adoption.
1. INTRODUCTION
Model-based UI design is an established field with a strong, but unfortunately small community. Although the potential has been shown through research prototypes and a few commercial tools, there are still few practitioners of model-based UI design methods.
The Analysis, Design and Modeling (AMD) tool market recently saw a decline in revenues, contrary to the expectations of the late 90s regarding the impact of the UML and other technologies in spreading modeling tool usage. There are no definite explanations to this unexpected decline, but there is strong evidence that AMD tools require a transition to more dynamic and developer-centered features that help address the needs of rapidly changing business and technology requirements.
A general understanding of adoption of technology is presented by [4]. His model is used by a recent ACM article [1]
about the iMode tehcnology, where it is explained as follows (quoting from the ACM article):
• Relative advantage: the degree to which the innovation is perceived as being better than the practice it supersedes; • Compatibility: the extent to which adopting the innovation is
compatible with what people do;
• Complexity: the degree to which an innovation is perceived as relatively difficult to understand and use;
• Trialability: the degree to which an innovation may be experimented with on a limited basis before making an adoption (or rejecting) decision;
• Observability: the degree to which the results of an innovation are visible to others;
Based on these characteristics and the qualities of current model-based UI design tools, we except that few will be adopted. And this is indeed the result of a recent survey on the Past, Present and Future of User Interface Tools, by Myers and colleagues [2]. They identified some issues that are important for evaluating which approaches were successful and which ones are promising in the future:
• The parts of the UI the tools address – the majority of successful tools and technologies focus on a particular part of the UI that is a significant problem, and which could be addressed thoroughly and effectively. Examples of approaches that failed to receive commercial success due to issues involved with trying to address the whole problem include UIMSs and Model-based and automatic generation techniques;
• Threshold and Ceiling – the difficulty of learning a new system and how much can be done using the system. Examples of unsuccessful approaches that suffered from the high threshold problem include formal languages and constraints;
• Path of Least Resistance – the most successful tools are those that lead to good UIs. Counter-examples include formal languages, which promoted rigid sequences of actions that are highly undesirable in modern non-modal Uis;
• Predictability – developers typically resist tools that can provide unpredictable results. The majority of tools Copyright is held by the author/owner(s).
IUI’04, Jan. 13–16, 2004, Madeira, Funchal, Portugal. ACM 1-58113-815-6/04/0001.
employing automatic techniques (e.g. model-based systems) made the link between the specification and the result difficult to understand and control;
• Moving Targets – good tools become available when that task is less important or even obsolete. Nearly all unsuccessful approaches succumbed to the moving-target problem. UIMSs, language-based approaches, constraints and model-based systems were designed to support a flexible variety of interaction styles and became less important with standardization of the desktop UI.
In the AMD industry there is a movement from Model Driven to Model Execution approaches. Both use models as the central artifacts of the development and maintenance process. Model Execution approaches promises moderate to high threshold but with the advantage of providing high ceiling. Well established software domains can exploit these approaches to analyze, design and generate the full applications with less resources and faster. It is not clear however, whether the user interface design community will endorse this approach. Next generation model-based tools needs to be perceived as useful. As stated by the Novak's rule [3]: "No body will create applications using specifications (models), if they can do it faster directly coding." This implies: tools and methods should be agile, useful, and easy to use.
The workshop will focus on not just why, but also what can be done to improve on the situation. Note however, that this workshop’s focus is more on usability (in a broad sense) of methods and tools than on theoretic problems. Therefore, personal experiences and practice are just as important for identifying problems. As a result of the workshop, a common vision of the next generation UI methods and tools could be achieved. Necessary steps to achieve the vision will also be discussed.
2. OBJECTIVES
The objectives include reviewing state of the art of MB-UID tools, discussing some questions about user interface design (UID) methods and tools, based on practical experiences.
Suggested topics and open questions to discuss are as follows:
1. Stories of success and failure • What has been shown to work?
• Usage context (org/proj/participants) that is required for successful use of model-based UI design methods • When shouldn’t model-based methods be used?
2. What are the desired properties for UID tools? 3. What are the unsolved problems with UI tools?
• maintenance (respect to domain models, etc.),
• standardization of UI models (UML lacks of UI primitives)
• round-trip problem (regeneration of UIs without loosing manual changes)
4. Integration with existing methods and tools • Using UML for UI design
• Extending UML with UI-specific constructs
• User-centred design, prototyping and model-based design
• Usage-centred design, can it be merged with more formal methods
• GUI-builders and model-based tools, possibility of hybrid tools
5. Educating industry (and students as potential practitioners) • How do we present our methods to potential
practioners?
• How may we introduce model-based UID methods in the curriculum?
6. Building open tools
• Sharing models and opening up existing tools
• Meta-modelling (possibly extending UML), MDA-based tool construction
• Open-sourcing and cooperating on tools (ala ArgoUML/ARGOi)
A common vision of the current state and a set of requirements for the next generation of model-based UI design tools will be the basis for collaboration among participants in joint research, development and publication.
3. REFERENCES
[1] Barnes, S. J., Huff, S. L. Rising Sun: iMode and the Wireless Internet. Communications of the ACM, 46, 79-84, 2003. [2] Myers, B., Hudson, S. and Pausch, R., Past, Present, and
Future of User Interface Software Tools. ACM Transactions on Computer-Human Interaction, 2000, 7, 3-28.
[3] Novak G.S. Novak’s rule: http://www.cs.utexas.edu/users/novak/index.html. [4] Rogers, E. Diffusion of Innovation. Free Press, New York,
1995.