We have created LADDER, the first language to describe how sketched diagrams in a domain are drawn, displayed, and edited. The difficulty in creating such a language is choosing a set of predefined entities that is broad enough to support a wide range of domains, while remaining narrow enough to be comprehensible. The language consists of predefined shapes, constraints, editing behaviors,and display methods, as well as a syntax for specifying a domain description sketch grammar and extending the language, ensuring that shapes and shape groups from many domains can be described.

Eye movement-based interaction offers the potential of easy, natural, and fast ways of interacting in virtual environments. However, there is little empirical evidence about the advantages or disadvantages of this approach. We developed a new interaction technique for eye movement interaction in a virtual environment and compared it to more conventional 3-D pointing. We conducted an experiment to compare performance of the two interaction types and to assess their impacts on spatial memory of subjects and to explore subjects' satisfaction with the two types of interactions. We found that the eye movementbased interaction was faster than pointing, especially for distant objects. However, subjects' ability to recall spatial information was weaker in the eye condition than the pointing one. Subjects reported equal satisfaction with both types of interactions, despite the technology limitations of current eye tracking equipment.

We discuss a novel type of interface, the intelligent gazeadded interface, and describe the design and evaluation of a sample gaze-added operating-system interface. Gaze-added interfaces, like current gaze-based systems, allow users to execute commands using their eyes. However, while most gaze-based systems replace the functionality of other inputs with that of gaze, gaze-added interfaces simply add gaze functionality that the user can employ if and when desired. Intelligent gaze-added interfaces utilize a probabilistic algorithm and user model to interpret gaze focus and alleviate typical problems with eye-tracking data. We extended a standard WIMP operating-system interface into a new interface, IGO, that incorporates intelligent gazeadded input. In a user study, we found that users quickly adapted to the new interface and utilized gaze effectively both alone and with other inputs.

Scalable Vector Graphics (SVG) is a language that describes two-dimensional vector graphics for storage and distribution on the Web. Unlike raster image formats, SVG-based images scale nicely to arbitrary resolutions and sizes. However, the current SVG standard provides little flexibility for taking into account varying viewing conditions, such as different screen formats, and there is little support for interactive exploration of a diagram. We introduce an extension to SVG called Constraint Scalable Vector Graphics (CSVG) that permits a more flexible description of figures. With CSVG, an image can contain objects whose positions and other properties are specified in relation to other objects using constraints, rather than being specified in absolute terms. For example, a box can be specified to remain inside another box, without being given an absolute position. The precise layout can then be left to the browser, which can adapt it dynamically to changing viewing conditions on the client side. Further extensions add support for alternate layouts, interaction, and declarative animation. Leveraging well-established methods for linear constraint solving, we implemented a prototype viewer for CSVG by embedding our Cassowary constraint solver into an existing SVG renderer.

This paper describes ICON, a novel editor designed to configure a set of input devices and connect them to actions into a graphical interactive application. ICON allows physically challenged users to connect alternative input devices and/or configure their interaction techniques according to their needs. It allows skilled users -- graphic designers or musicians for example -- to configure any ICON aware application to use their favorite input devices and interaction techniques (bimanual, voice enabled, etc.).

Involving graphic designers in the large-scale development of user interfaces requires tools that provide more graphical flexibility and support efficient software processes. These requirements were analysed and used in the design of the TkZinc graphical library and the IntuiKit interface design environment. More flexibility is obtained through a wider palette of visual techniques and support for iterative construction of images, composition and parametric displays. More efficient processes are obtained with the use of the SVG standard to import graphics, support for linking graphics and behaviour, and a unifying model-driven architecture. We describe the corresponding features of our tools, and show their use in the development of an application for airports. Benefits include a wider access to high quality visual interfaces for specialised applications, and shorter prototyping and development cycles for multidisciplinary teams.

Figure 1: Designing a puzzle UI with MaggLite. (a) Drawing UI. (b) Configuring interactions. (c) Using the application. This article presents MaggLite, a toolkit and sketch-based interface builder allowing fast and interactive design of post-WIMP user interfaces. MaggLite improves design of advanced UIs thanks to its novel mixed-graph architecture that dynamically combines scene-graphs with interactiongraphs. Scene-graphs provide mechanisms to describe and produce rich graphical effects, whereas interaction-graphs allow expressive and fine-grained description of advanced interaction techniques and behaviors such as multiple pointers management, toolglasses, bimanual interaction, gesture, and speech recognition. Both graphs can be built interactively by sketching the UI and specifying the interaction using a dataflow visual language. Communication between the two graphs is managed at runtime by components we call Interaction Access Points. While developers can extend the toolkit by refining built-in generic mechanisms, UI designers can quickly and interactively design, prototype and test advanced user interfaces by applying the MaggLite principle: “draw it, connect it and run it”. Categories and Subject Descriptors: H5.2 [Information Interfaces]: User Interfaces―Graphical user interfaces

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Abstract. Nowadays, designers of Virtual Reality (VR) applications are faced with the choice of a large number of different input and output devices leading to a growing number of interaction techniques. Usually VR interaction techniques are described informally, based on the actions users can perform within the VR environment. At implementation time, such informal descriptions (made at design time) yield to ambiguous interpretations by the developers. In addition, informal descriptions make it difficult to foresee the impact throughout the application of a modification of the interaction techniques. This paper discusses the advantages of using a formal description technique (called ICO) to model interaction techniques and dialogues for VR applications. This notation is presented via a case study featuring an immersive VR application. The case study is then used to show, through analysis of models, how the formal notation can help to ensure the usability, reliability and efficiency of virtual reality systems. 1

This chapter describes the area of human-computer interaction technique research in general and then describes research in several new types of interaction techniques under way at the Human-Computer Interaction Laboratory of the U.S. Naval Research Laboratory: eye movement-based interaction techniques, three-dimensional pointing, and, finally, using dialogue properties in interaction techniques.