As the variety in network service platforms and end user devices grows rapidly, content providers must constantly adapt their production system to support these new technologies. In this paper, we present a middleware platform for deploying highly interactive (television) applications over a diverse collection of networks and end user devices. As the user interface of such interactive applications may vary depending on the capabilities of the different target devices, our middleware uses UIML for the description of generic user interfaces. Our middleware platform also provides a pluggable support for new networks. A factor that highly complicates the design is the need for strict synchronization between an interactive application and video or audio data that is broadcasted. In order to support a maximum of functionality, downloadable application logic is used to provide the interactive services. As a test case, an evaluation setup was built, targeting both set-top boxes and mobile phones.

The diversity of end-user devices in combination with a growing user base poses important challenges for providing easy access to the huge amount of content and services currently available. Each device has its typical set of capabilities and characteristics that must be taken into account to create an appropriate user interface that provides interactive access to multimedia data and services. Furthermore, end-users also have their specific requirements that influence the accessibility of data and services for individual access. The approach we present in this paper is geared towards the idea of universal access to interactive multimedia data and services for everyone, independent of the user characteristics or end-user device capabilities. For this purpose we combine user and device models with high-level user interface description languages in order to decouple the interface presentation from its platform, and to generate the most suitable interface on a per-user, per- device basis making use of the semantics that are provided by user and device profile.

Methods to support the creation of multi-device user interfaces typically use some type of abstraction of the user interface design. To retrieve the final user interface from the abstraction a transformation will be applied that specializes the abstraction for a particular target platform. The User Interface Markup Language (UIML) offers a way to create multi-device user interface descriptions while maintaining the consistency of certain aspects of a user interface across platforms. We extended the UIML language with support for layout constraints. Designers can create layout templates based on constraints that limit the ways a user interface can rearrange across platforms. This results in a higher degree of consistency and reusability of interface designs.

The wide diversity of consumer devices has led to new methodologies and techniques to make digital content available over a broad range of devices with minimal effort. In particular the design of the interactive parts of a system has been the subject of a lot of research efforts because these parts are the most visible and are critical for the usability (and thus use) of a system. One thing that is missing in many current approaches is the ability to combine these new methodologies and techniques with a user-centric approach to ensure preferences from and requirements for a specific user are taken into account besides the device adaptations. In this paper we analysed the applicability of MPEG-21, part 7: Digital Item Adaptation, for the adaptation of a user interface to user characteristics. We show how the high-level XML-based user interface description language UIML in combination with an MPEG-21-based user profile enables designers to create accessible and personalised multi-device user interfaces. Using this combination results in user interfaces that can be deployed on a broad range of devices while taking into account user preferences with minimal effort. This approach enhances accessibility to digital items on various platforms, since all interactions with digital items should be supported by an appropriate user interface.

As the diversity of available computing devices increases it becomes more difficult to adapt User Interface development to support the full range of available devices. One of the difficulties are the different GUI libraries: to use an alternative library or device one is forced to redevelop the interface completely for the alternative GUI library. To overcome these problems the User Interface Mark-up Language (UIML) specification has been proposed, as a way of glueing the interface design to different GUI libraries in different environments without further efforts. In contrast with other approaches UIML has matured and has some implementations proving its usefulness. We introduce the first UIML renderer for the .Net framework, a framework that can be accessed by different kinds of programming languages and can use different kinds of widget sets. We show that its properties, among them its reflection mechanism, are suitable for the development of a reusable and portable UIML renderer. The suitability for multi-device rendering is discussed in comparison with our own multi-device UI framework Dygimes. The focus is on how layout management can be generalised in the specification to allow the GUI to adapt to different screen sizes.

This collection highlights advancements in User Interface Description Languages (UIDLs), focusing on XML-based solutions for device-independent and context-sensitive user interface development. Contributions cover a range of topics including dynamic generation of multimodal interfaces, model-driven UIDL integration, and language extensibility for multi-device scenarios. Innovations in UIDL frameworks, such as UIML and USIXML, showcase methods to enhance reusability, adaptability, and scalability in HCI tools. Practical applications, case studies, and evaluations of UIDL frameworks underscore their potential in improving usability, accessibility, and integration across diverse computing environments.

We present two ongoing research efforts, both aim to support the use of models for designing (multi- and multiple-device) User Interfaces. The first tool, a part of the Dygimes framework, shows how context and tasks can be combined. It allows to generate prototype interfaces from context-sensitive task models. It builds upon a runtime environment in Java and an XML-based High Level User Interface Description (HLUID) language to generate the prototype interface. The second tool, uiml.net, experiments with another HLUID and another runtime enviroment to generate interfaces. Both tools are work in progress.