Jean Vanderdonckt

A Unifying Reference Framework for Multi-Target User Interfaces

This paper describes a framework that serves as a reference for classifying user interfaces supporting multiple targets, or multiple contexts of use in the field of context-aware computing. In this framework, a context of use is decomposed in three facets: the end users of the interactive system, the hardware and software computing platform with which the user have to carry out their interactive tasks and the physical environment where they are working. Therefore, a context-sensitive user interface is a user interface that exhibits some capability to be aware of the context (context awareness) and to react to changes of this context. This paper attempts to provide a unified understanding of context-sensitive user interfaces rather than a prescription of various ways or methods of tackling different steps of development. Rather, the framework structures the development life cycle into four levels of abstraction: task and concepts, abstract user interface, concrete user interface and final user interface. These levels are structured with a relationship of reification going from an abstract level to a concrete one and a relationship of abstraction going from a concrete level to an abstract one. Most methods and tools can be more clearly understood and compared relative to each other against the levels of this framework. In addition, the framework expresses when, where and how a change of context is considered and supported in the context-sensitive user interface thanks to a relationship of translation. In the field of multi-target user interfaces is also introduced, defined, and exemplified the notion of plastic user interfaces. These user interfaces support some adaptation to changes of the context of use while preserving a predefined set of usability properties

USIXML: a language supporting multi-path development of user interfaces

USer Interface eXtensible Markup Language (USIXML) consists in a User Interface Description Language (UIDL) allowing designers to apply a multi-path development of user interfaces. In this development paradigm, a user interface can be specified and produced at and from different, and possibly multiple, levels of abstraction while maintaining the mappings between these levels if required. Thus, the development process can be initiated from any level of abstraction and proceed towards obtaining one or many final user interfaces for various contexts of use at other levels of abstraction. In this way, the model-to-model transformation, which is the cornerstone of Model-Driven Architecture (MDA), can be supported in multiple configurations, based on composition of three basic transformation types: abstraction, reification, and translation.

Applying model-based techniques to the development of UIs for mobile computers

Mobile computing poses a series of unique challenges for user interface design and development: user interfaces must now accommodate the capabilities of various access devices and be suitable for different contexts of use, while preserving consistency and usability. We propose a set of techniques that will aid UI designers who are working in the domain of mobile computing. These techniques will allow designers to build UIs across several platforms, while respecting the unique constraints posed by each platform. In addition, these techniques will help designers to recognize and accommodate the unique contexts in which mobile computing occurs. Central to our approach is the development of a user-interface model that serves to isolate those features that are common to the various contexts of use, and to specify how the user-interface should adjust when the context changes. We claim that without some abstract description of the UI, it is likely that the design and the development of user-interfaces for mobile computing will be very time consuming, error-prone or even doomed to failure.

Encapsulating knowledge for intelligent automatic interaction objects selection

TRIDENT is a set of interactive tools that automatically generates a user interface for highly-interactive business-oriented applications. It includes an intelligent interaction objects selection based on three different concepts. First, on object oriented typology classifies abstract interaction objects to allow a presentation independent selection. Second, guidelines are translated into automatic rules to select abstract interaction objects from both an application data model and a dialog model. Third, these guidelines are encapsulated in a decision tree technique to make the reasoning obvious to the user. This approach guarantees a target environment independent user interface. Once this specified, abstract interaction objects are mapped into concrete interaction objects to produce the observable interface.

A MDA-compliant environment for developing user interfaces of information systems

To cope with the ever increasing diversity of markup languages, programming languages, tool kits and interface development environments, conceptual modeling of user interfaces could bring a framework for specifying, designing, and developing user interfaces at a level of abstraction that is higher than the level where code is merely manipulated. For this purpose, a complete environment is presented based on conceptual modeling of user interfaces of information systems structured around three axes: the models that characterize a user interface from the end users viewpoint and the specification language that allows designers to specify such interfaces, the method for developing interfaces in forward, reverse, and lateral engineering based on these models, and a suite of tools that support designers in applying the method based on the models. This environment is compatible with the Model-Driven Architecture recommendations in the sense that all models adhere to the principle of separation of concerns and are based on model transformation between the MDA levels. The models and the transformations of these models are all expressed in UsiXML (User Interface eXtensible Markup Language) and maintained in a model repository that can be accessed by the suite of tools. Thanks to this environment, it is possible to quickly develop and deploy a wide array of user interfaces for different computing platforms, for different interaction modalities, for different markup and programming languages, and for various contexts of use.

Graceful degradation of user interfaces as a design method for multiplatform systems

This paper introduces and describes the notion of graceful degradation as a method for supporting the design of user interfaces for multiplatform systems when the capabilities of each platform are very different. The approach is based on a set of transformational rules applied to a single user interface designed for the less constraint platform. A major concern of the graceful degradation approach is to guarantee a maximal continuity between the platform specific versions of the user interface. In order to guarantee the continuity property, a priority ordering between rules is proposed. That ordering permits to apply first the rules with a minimal impact on the multiplatform system continuity.

Development milestones towards a tool for working with guidelines

Several tools for working with guidelines already exist, both as commercial products as well as within research and development. As these tools frequently manipulate guidelines during many development steps of a user interface of an interactive application, they can overthrow any approach followed to develop this application. They also raise the fundamental question of to what extent can we trust these tools. To answer this question, we introduce five development milestones through which we must pass to produce a high quality tool for working with guidelines: 1. An initial unstructured but comprehensive set of guidelines is formed by collecting, gathering, merging, compiling guidelines from all available world-wide ergonomic sources. 2. The initial set is sorted and classified within a single organising framework. 3. A methodology, paying particular attention to finding and applying relevant guidelines is developed for grounding interactive applications on the organised set of guidelines. 4. The structured guidelines and the supporting methodology are given computational representations for manipulation by computer-based tools. 5. The methodology developed in (3) is further modified to optimise the effectiveness of computer-assisted user interface design. In this paper, we define these milestones and their associated goals, specify a general procedure and discuss some problems raised at each milestone. We then deliver an analytic synthesis of various experiences acquired to solve these problems and we discuss the validity of these experiences from the point of view of completeness, consistency and correctness. From these experiences, we finally draw some lessons useful for any future usage and development of a tool for working with guidelines

A Review of XML-compliant User Interface Description Languages

A review of XML-compliant user interface description languages is produced that compares a significant selection of various languages addressing different goals, such as multi-platform user interfaces, device-independence, content delivery, and user interfaces virtually defined. There has been a long history and tradition to attempt to capture the essence of user interfaces at various levels of abstraction for different purposes. The return of this question today gains more attraction, along with the dissemination of XML markup languages, and gives birth to many proposals for a new user interface description language. Consequently, there is a need to conduct an in-depth analysis of features that make all these proposals discriminant and appropriate for any specific purpose. The review is extensively conducted on a significant subset of such languages based on an analysis grid and user interfaces that we tried to implement across these languages.

Fusion engines for multimodal input: a survey

Fusion engines are fundamental components of multimodal inter-active systems, to interpret input streams whose meaning can vary according to the context, task, user and time. Other surveys have considered multimodal interactive systems; we focus more closely on the design, specification, construction and evaluation of fusion engines. We first introduce some terminology and set out the major challenges that fusion engines propose to solve. A history of past work in the field of fusion engines is then presented using the BRETAM model. These approaches to fusion are then classified. The classification considers the types of application, the fusion principles and the temporal aspects. Finally, the challenges for future work in the field of fusion engines are set out. These include software frameworks, quantitative evaluation, machine learning and adaptation.

Derivation of a Dialog Model from a Task Model by Activity Chain Extraction

Over the last few years, Model-Based User Interface Design has become an important tool for creating multi-device User Interfaces. By providing information about several aspects of the User Interface, such as the task for which it is being built, different User Interfaces can be generated for fulfilling the same needs although they have a different concrete appearance. In the process of making User Interfaces with a Model-Based Design approach, several models can be used: a task model, a dialog model, a user model, a data model,etc. Intuitively, using more models provides more (detailed) information and will create more appropriate User Interfaces. Nevertheless, the designer must take care to keep the different models consistent with respect to each other. This paper presents an algorithm to extract the dialog model (partially) from the task model. A task model and dialog model are closely related because the dialog model defines a sequence of user interactions, an activity chain, to reach the goal postulated in the task specification. We formalise the activity chain as a State Transition Network, and in addition this chain can be partially extracted out of the task specification. The designer benefits of this approach since the task and dialog model are consistent. This approach is useful in automatic User Interface generation where several different dialogs are involved: the transitions between dialogs can be handled smoothly without explicitely implementing them.