The conflux of two growing areas of technologycollaboration and visualization-into a new research direction, collaborative visualization, provides new research challenges. Technology now allows us to easily connect and collaborate with one another-in settings as diverse as over networked computers, across mobile devices, or using shared displays such as interactive walls and tabletop surfaces. Digital information is now regularly accessed by multiple people in order to share information, to view it together, to analyze it, or to form decisions. Visualizations are used to deal more effectively with large amounts of information while interactive visualizations allow users to explore the underlying data. While researchers face many challenges in collaboration and in visualization, the emergence of collaborative visualization poses additional challenges but is also an exciting opportunity to reach new audiences and applications for visualization tools and techniques.The purpose of this article is (1) to provide a definition, clear scope, and overview of the evolving field of collaborative visualization, (2) to help pinpoint the unique focus of collaborative visualization with its specific aspects, challenges, and requirements within the intersection of general computer-supported cooperative work (CSCW) and visualization research, and (3) to draw attention to important future research questions to be addressed by the community. We conclude by discussing a research agenda for future work on collaborative visualization and urge for a new generation of visualization tools that are designed with collaboration in mind from their very inception.

Despite typically receiving little emphasis in visualization research, interaction in visualization is the catalyst for the user's dialogue with the data, and, ultimately, the user's actual understanding and insight into this data. There are many possible reasons for this skewed balance between the visual and interactive aspects of a visualization. One reason is that interaction is an intangible concept that is difficult to design, quantify, and evaluate. Unlike for visual design, there are few examples that show visualization practitioners and researchers how to best design the interaction for a new visualization. In this paper, we attempt to address this issue by collecting examples of visualizations with "best-in-class" interaction and using them to extract practical design guidelines for future designers and researchers. We call this concept fluid interaction, and we propose a operational definition in terms of the direct manipulation and embodied interaction paradigms, the psychological concept of "flow", and Norman's gulfs of execution and evaluation.

No abstract

Abstract.Evaluating new approaches, be it new interaction techniques, new applications or even new hardware, is an important task, which has to be done to ensure both usability and user satisfaction. The drawback of evaluating subjective parameters is that this can be relatively time consuming, and the outcome is possibly quite imprecise. Considering the recent release of costefficient commercial EEG headsets, we propose the utilization of electroencephalographic (EEG) devices for evaluation purposes. The goal of our research is to evaluate if a commercial EEG headset can provide cutting-edge support during user studies and evaluations. Our results are encouraging and suggest that wireless EEG technology is a viable alternative for measuring subjectivity in evaluation scenarios.