Fisheye views allow people to see both a focus region and the surrounding context in the same window. However, the magnification effects of the fisheye lens can cause several problems for users. One of these is focus-targeting, where a user moves the focus to a new location. Magnification makes focus-targeting difficult because objects appear to move as the focus point approaches them. This paper examines how the distortion of a fisheye view affects focus-targeting performance, and present a technique called speed-coupled flattening (SCF) as a way to improve focus targeting in distortion-oriented views. SCF dynamically reduces the distortion level of a fisheye based on pointer velocity and acceleration. In an experiment, the technique resulted in significant reductions in both targeting time and targeting errors. By adjusting distortion based on the user's activity, we can improve usability without requiring the user to manipulate any additional view controls.

User interfaces can improve task performance by exploiting the powerful human capabilities for spatial cognition. This opportunity has been demonstrated by many prior experiments. It is tempting to believe that providing greater spatial flexibility---by moving from flat 2D to 3D user interfaces---will further enhance user performance. This paper describes an experiment that investigates the effectiveness of spatial memory in real-world physical models and in equivalent computer-based virtual systems. The different models vary the user's freedom to use depth and perspective in spatial arrangements of images representing web pages. Results show that the subjects' performance deteriorated in both the physical and virtual systems as their freedom to locate items in the third dimension increased. Subjective measures reinforce the performance measures, indicating that users found interfaces with higher dimensions more `cluttered' and less efficient.

1 An empirical comparison of three commercial information visualization systems on three different databases is presented. The systems use different paradigms for visualizing data. Tasks were selected to be "ecologically relevant", i.e. meaningful and interesting in the respective domains. Users of one system turned out to solve problems significantly faster than users of the other two, while users of another system would supply significantly more correct answers. Reasons for these results and general observations about the studied systems are discussed. 1.

this article is that it demonstrates where novel focus# context views might become particularly useful for experienced users. It appears that novel, 3D interactive techniques might best be introduced alongside more familiar 2D visualizations, allowing the user to mix interaction strategies as necessary. The article by North and Shneiderman (2000) in this issue echoes this latter "nding

Abstract. Ontologies can represent large, multidimensional spaces: classical

guidelines for categorized overviews

In this article we present a novel approach, the 2-Layer Interface Paradigm (2LIP), for designing simple yet interactive 3D web applications, an attempt to marry advantages of 3D experience with the advantages of the narrative structure of hypertext. The hypertext information, together with graphics, and multimedia, is presented semi-transparently on the foreground layer. It overlays the 3D representation of the information displayed in the background of the interface. Hyperlinks are used for navigation in the 3D scenes (in both layers). We introduce a reference implementation of 2LIP: Copernicus-The Virtual 3D Encyclopedia, which can become a model for building 3D Wikipedia. Based on the evaluation of Copernicus we show that designing web interfaces according to 2LIP provides users with a better experience during browsing the Web, has a positive effect on the visual and associative memory, improves spatial cognition of presented information, and increases overall user’s satisfaction without harming the interaction. which might be hard to understand in the context of the Internet hypertext environment. We strongly believe that user interfaces should be as simple as possible. We have worked out a new way for designing interactive 3D web applications- 2-Layer Interface Paradigm (2LIP) [Jankowski and Kruk 2008]. 2LIP is an attempt to marry advantages of 3D experience with the advantages of the narrative structure of hypertext. It assumes that building graphical user interfaces involves the integration of two layers (see Figure 1): (1) the background layer is a 3D scene; (2) the foreground layer, above the 3D view is the hypertextual content, together with graphics, and multimedia (e.g., videos or other interactive 3D scenes). Hyperlinks are used for navigation in the 3D scenes (in both layers).

We propose the combination of two recently introduced methods for the interactive visual data mining of large collections of data. Both, Hyperbolic Multi-Dimensional Scaling (HMDS) and Hyperbolic Self-Organizing Maps (HSOM) employ the extraordinary advantages of the hyperbolic plane (H2): (i) the underlying space grows exponentially with its radius around each point - ideal for embedding high-dimensional (or hierarchical) data; (ii) the Poincar e model of the IH exhibits a fish-eye perspective with a focus area and a context preserving surrounding; (iii) the mouse binding of focus-transfer allows intuitive interactive navigation.

† Author for correspondence. Prior research has shown that the efficient use of graphical user interfaces is strongly dependent on human capabilities for spatial cognition. One facet of spatial cognition is the ability to quickly and accurately recall and access the location of objects in a spatial arrangement. This paper describes a series of experiments aimed at determining whether three-dimensional user interfaces better support spatial memory than their more traditional two-dimensional counterparts. The experiments are conducted using both computer-supported systems and physical models that vary the depth and perspective cues in spatial arrangements of interface items. The physical models were used to escape some of the dimensional ambiguities that are hard to control using computer displays. Results strongly suggest that adding a third dimension to computer displays does not aid users ’ spatial memory. Although there were no significant differences between the effectiveness of spatial memory when using two- and three-dimensional computer interfaces, participants ’ memory for the location of cards representing web-pages was reliably better when using a two-dimensional physical model than when using an equivalent three-dimensional physical model.

Search in and presentation of multimedia collections is an important and complex task. Often it involves various search strategies and the visualization of found object collections. Technically, search strategies can be formulated using distance measures between object pairs. In this paper we propose the use of a projection based method to dynamically arrange a set of objects (here images) given a notion of image similarity (an interactive user choice). This approach uses the previously introduced Hyperbolic Multidimensional Scaling method (HMDS) in order to find spatial layouts of the objects in the hyperbolic plane IH 2 based on pairwise dissimilarity data. The circular Poincaré model of the IH 2 allows effective human-computer interaction: by moving the “focus ” via mouse the user can navigate in the images without loosing the “context ” around the center, which appears with gradually lower resolution. The exponential growth of area around each point in the IH 2 makes this non-Euclidean projection space extraordinary for the layout- also for images. We use the HMDS technique to interactively mix various concepts of “image similarity ” (based on visual and annotation information). Depending on the preferences and the actual task the user can modulate the distance metric while observing the resulting rearrangement of the images in IH 2. The concept can be generalized to any kind of multimedia content, given suitable similarity functions on the content, e.g. distances in ontologies, sound features, or multimedia descriptions etc. 1.