In this paper we describe a novel approach for searching large data sets from a mobile phone. Existing interfaces for mobile search require keyword text entry and are not suited for browsing. Our alternative uses a hybrid model to deemphasize tedious keyword entry in favor of iterative data filtering. We propose navigation and selection of hierarchical metadata (facet navigation), with incremental text entry to further narrow the results. We conducted a formative evaluation to understand the relative advantages of keyword entry versus facet navigation for both browse and search tasks on the phone. We found keyword entry to be more powerful when the name of the search target is known, while facet navigation is otherwise more effective and strongly preferred. Author Keywords Mobile devices, faceted metadata, search interfaces, visual

Abstract—Existing information-visualization techniques that target small screens are usually limited to exploring a few hundred items. In this article we present a scatterplot tool for Personal Digital Assistants that allows the handling of many thousands of items. The application’s scalability is achieved by incorporating two alternative interaction techniques: a geometric-semantic zoom that provides smooth transition between overview and detail, and a fisheye distortion that displays the focus and context regions of the scatterplot in a single view. A user study with 24 participants was conducted to compare the usability and efficiency of both techniques when searching a book database containing 7500 items. The study was run on a pen-driven Wacom board simulating a PDA interface. While the results showed no significant difference in task-completion times, a clear majority of 20 users preferred the fisheye view over the zoom interaction. In addition, other dependent variables such as user satisfaction and subjective rating of orientation and navigation support revealed a preference for the fisheye distortion. These findings partly contradict related research and indicate that, when using a small screen, users place higher value on the ability to preserve navigational context than they do on the ease of use of a simplistic, metaphor-based interaction style. Index Terms—Small screen, PDA, scatterplot, zoom, fisheye, focus+context. 1

While zoomable user interfaces can improve the usability of applications by easing data access, a drawback is that some users tend to become lost after they have zoomed in. Previous studies indicate that this effect could be related to individual differences in spatial ability. To overcome such orientation problems, many desktop applications feature an additional overview window showing a miniature of the entire information space. Small devices, however, have a very limited screen real estate and incorporating an overview window often means pruning the size of the detail view considerably. Given this context, we report the results of a user study in which 24 participants solved search tasks by using two zoomable scatterplot applications on a PDA- one of the applications featured an overview, the other relied solely on the detail view. In contrast to similar studies for desktop applications, there was no significant difference in user preference between the interfaces. On the other hand, participants solved search tasks faster without the overview. This indicates that, on small screens, a larger detail view can outweigh the benefits gained from an overview window. Individual differences in spatial ability did not have a significant effect on task-completion times although results suggest that participants with higher spatial ability were slowed down by the overview more than low spatial-ability users.

This paper describes the facilities we built to run a self-contained digital library on an iPod. The digital library software used was the open source package Greenstone, and the paper highlights the technical problems that were encountered and solved. It attempts to convey a feeling for the kind of issues that must be faced when adapting standard DL software for non-standard, leading-edge devices. Categories and Subject Descriptors

Abstract. We have created an experimental prototype that enhances an ordinary personal media player by adding digital library capabilities. It does not enable access to a remote digital library from a user’s PDA; rather, it runs a complete, standard digital library server environment on the device. Being optimized for multimedia information, this platform has truly vast storage capacity. It raises the possibility of not just personal collections but entire institutional-scale digital libraries that are fully portable. Our implementation even allows the device to be configured as a web server to provide digital library content over a network, inverting the standard mobile client-server configuration and incidentally providing full-screen access. Anecdotal yet compelling evidence as to the usefulness of being able to access a self-sufficient digital library anytime, anywhere is given through an example built from the PDF files of the Joint ACM/IEEE digital library conference. Other examples include the Complete Works of Shakespeare and collections on Humanitarian Aid. This paper describes the facilities we built, focusing on interface issues that were encountered and solved. Keywords: Portable Digital Libraries, Personal Media Player, Multimedia.

In this paper, we present MoStarD, a mobile application that couples starfield displays with dynamic queries to support user exploration of large datasets. A novel space compression technique enables users to compress areas of the starfield display to optimize screen space usage and easily focus on specific subsets of a dataset.

Fig. 1. Applying the proposed Two-Step-Mapping to generate scatterplots showing the same clusters on different display devices in our smart meeting environment. Abstract. Visual analysis sessions are increasingly conducted in multidisplay environments. However, presenting a data set simultaneously on heterogenous displays to users is a challenging task. In this paper we propose a two-step mapping strategy to address this problem. The first mapping step applies primary mapping functions to generate the same basic layout for all output devices and adapts the object size based on the display characteristic to guarantee the visibility of all elements. The second mapping step introduces additional visual cues to enhance the effectiveness of the visual encoding for different output devices. To demonstrate the Two-Step-Mapping we apply this concept to scatter plots presenting cluster data. 2 Axel Radloff, Martin Luboschik, Mike Sips, and Heidrun Schumann 1