A digital tabletop, such as the one shown in Figure 1

Tables provide a large and natural interface for supporting direct manipulation of visual content for human-to-human interactions. Such surfaces also support collaboration, coordination, and parallel problem solving. However, the direct-touch table metaphor also presents considerable challenges, including the need for input methods that transcend traditional mouse-and keyboardbased designs.

Abstract. This article proposes a framework that will help analyze current and future output multimodal user interfaces. We first define an output multimodal system. We then present our framework that identifies several different combinations of modalities and their characteristics. This framework assists in the selection of the most appropriate modalities for achieving efficient multimodal presentations. The discussion is illustrated with MulTab (Multimodal Table), an output multimodal system for managing large tables of numerical data.

This paper presents visualization and layout schemes developed for a novel circular user interface designed for a round, tabletop display. Since all the displayed items are in a polar coordinate system, many interface and visualization schemes must be revisited to account for this new layout of UI elements. We first discuss the direct implications of such a circular interface on document orientation. Then we describe two types of fisheye deformation of the circular layout and explain how to use them in a multiperson collaborative interface. These two schemes provide a general layout framework for circular interfaces. We have also designed a new visualization technique derived from the particularities of the circular layout we have highlighted. In this technique the user control the layout of the elements of a hierarchical tree. Our approach is not to automatically compute the most effective position of the nodes and leaves of a tree but to provide the user rich interaction possibilities to easily and quickly produce a layout comparable to the hyperbolic view developed at Xerox PARC. Finally, we discuss future work and possible visualization techniques based on different information structures. The visualization work presented in this paper is part of our ongoing Personal Digital Historian (PDH) research project. The overall goal of PDH is to investigate ways to effectively and intuitively organize, navigate, browse, present and visualize digital data in an interactive multi-person conversational setting. This work may not be copied or reproduced in whole or in part for any commercial purpose. Permission to copy in whole or in part without payment of fee is granted for nonprofit educational and research purposes provided that all such whole or partial copies include the following: a notice that such copying is by permission of Mitsubishi Electric Research Laboratories, Inc.; an acknowledgment of the authors and individual contributions to the work; and all applicable portions of the copyright notice. Copying, reproduction, or republishing for any other purpose shall require a license with payment of fee to Mitsubishi Electric Research Laboratories, Inc. All rights reserved. AbstractThis paper presents visualization and layout schemes developed for a novel circular user interface designed for a round, tabletop display. Since all the displayed items are in a polar coordinate system, many interface and visualization schemes must be revisited to account for this new layout of UI elements. We first discuss the direct implications of such a circular interface on document orientation. Then we describe two types of fisheye deformation of the circular layout and explain how to use them in a multiperson collaborative interface. These two schemes provide a general layout framework for circular interfaces. We have also designed a new visualization technique derived from the particularities of the circular layout we have highlighted. In this technique the user control the layout of the elements of a hierarchical tree...

is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. This paper examines some aspects of the usefulness of interactive tabletop systems, if and how these impact collaboration. We chose creative problem solving such as brainstorming as an application framework to test several collaborative media: the use of pen-and-paper tools, the ''around-the-table'' form factor, the digital tabletop interface, the attractiveness of interaction styles. Eighty subjects in total (20 groups of four members) participated in the experiments. The evaluation criteria were task performance, collaboration patterns (especially equity of contributions), and users' subjective experience. The ''aroundthe-table'' form factor, which is hypothesized to promote social comparison, increased performance and improved collaboration through an increase of equity. Moreover, the attractiveness of the tabletop device improved subjective experience and increased motivation to engage in the task. However, designing attractiveness seems a highly challenging issue, since overly attractive interfaces may distract users from the task.