Nicholas F. Polys

Information-rich virtual environments: theory, tools, and research agenda

Virtual environments (VEs) allow users to experience and interact with a rich sensory environment, but most virtual worlds contain only sensory information similar to that which we experience in the physical world. Information-rich virtual environments (IRVEs) combine the power of VEs and information visualization, augmenting VEs with additional abstract information such as text, numbers, or graphs. IRVEs can be useful in many contexts, such as education, medicine, or construction. In our work, we are developing a theoretical foundation for the study of IRVEs and tools for their development and evaluation. We present a working definition of IRVEs, a discussion of information display and interaction in IRVEs. We also describe a software framework for IRVE development and a testbed enabling evaluation of text display techniques for IRVEs. Finally, we present a research agenda for this area.

Effects of information layout, screen size, and field of view on user performance in information‐rich virtual environments

This paper describes our recent experimental evaluation of Information‐Rich Virtual Environment (IRVE) interfaces. To explore the depth cue/visibility tradeoff between annotation schemes, we design and evaluate two information layout techniques to support search and comparison tasks. The techniques provide different depth and association cues between objects and their labels: labels were displayed either in the virtual world relative to their referent (Object Space) or on an image plane workspace (Viewport Space). The Software Field of View (SFOV) was controlled to 60° or 100° of vertical angle and two groups were tested: those running on a single monitor and those on a tiled nine‐panel display. Users were timed, tracked for correctness, and gave ratings for both difficulty and satisfaction on each task. Significant advantages were found for the Viewport interface, and for high SFOV. The interactions between these variables suggest special design considerations to effectively support search and comparison performance across monitor configurations and projection distortions. Copyright

Effects of information layout, screen size, and field of view on user performance in information-rich virtual environments

This paper describes our recent experimental evaluation of Information-Rich Virtual Environment (IRVE) interfaces. To explore the depth cue/visibility tradeoff between annotation schemes, we design and evaluate two information layout techniques to support search and comparison tasks. The techniques provide different depth and association cues between objects and their labels: labels were displayed either in the virtual world relative to their referent (Object Space) or on an image plane workspace (Viewport Space). The Software Field of View (SFOV) was controlled to 60 or 100 degrees of vertical angle and two groups were tested: those running on a single monitor and those on a tiled nine-panel display. Users were timed, tracked for correctness, and gave ratings for both difficulty and satisfaction on each task. Significant advantages were found for the Viewport interface, and for high SFOV. The interactions between these variables suggest special design considerations to effectively support search and comparison performance across monitor configurations and projection distortions.

The role of Depth and Gestalt cues in information-rich virtual environments

Managing the layout of multi-dimensional visualizations is a crucial concern for the development of effective visual analytic interfaces. In these environments, heterogeneous and multi-dimensional information must be structured and combined into data representations that demand low cognitive resources but yield accurate mental models and insights. In this paper, we use Information-Rich Virtual Environments (IRVE) to articulate crucial tradeoffs in the use of Depth and Gestalt cues in text label layouts. We present a design space and evaluation methodology to explore the usability effects of these tradeoffs and collect results from a series of user studies. These lessons are posed as a set of design guidelines to aid developers of new, advantageous interfaces and specifications.

A virtual look at Epstein-Barr virus infection: simulation mechanism.

Epstein-Barr virus (EBV) is an important human pathogen that establishes a life-long persistent infection and for which no precise animal model exists. In this paper, we describe in detail an agent-based model and computer simulation of EBV infection. Agents representing EBV and sets of B and T lymphocytes move and interact on a three-dimensional grid approximating Waldeyers ring, together with abstract compartments for lymph and blood. The simulation allows us to explore the development and resolution of virtual infections in a manner not possible in actual human experiments. Specifically, we identify parameters capable of inducing clearance, persistent infection, or death.

PathSim visualizer: an Information-Rich Virtual Environment framework for systems biology

Increasingly, biology researchers and medical practitioners are using computational tools to model and analyze dynamic systems across scales from the macro to the cellular to the biochemical level. We are using Information-Rich Virtual Environments (IRVEs) to display the results of biological simulations, and to allow users to interact with those simulations. While simulation architectures, algorithms, and processing power have enjoyed continuous optimization to date, the user interfaces to these applications have not. The problems of designing such IRVE interfaces arise from the requirement that a variety of spatial and abstract information must be integrated into one coherent experience for the user. This paper explores the design and development issues encountered in our implementation of a bioinformatics application, PathSim (Pathogen Simulation). Specifically, we describe the information and interaction issues in building a front-end tool to visually analyze the results of an agent-based immunology simulation. Finally, we present custom scenegraph objects and consider candidate functionality for future standards components.

High-precision registration between zebrafish brain atlases using symmetric diffeomorphic normalization

Abstract Atlases provide a framework for spatially mapping information from diverse sources into a common reference space. Specifically, brain atlases allow annotation of gene expression, cell morphology, connectivity, and activity. In larval zebrafish, advances in genetics, imaging, and computational methods now allow the collection of such information brain-wide. However, due to technical considerations, disparate datasets may use different references and may not be aligned to the same coordinate space. Two recent larval zebrafish atlases exemplify this problem: Z-Brain, containing gene expression, neural activity, and neuroanatomical segmentations, was acquired using immunohistochemical stains, while the Zebrafish Brain Browser (ZBB) was constructed from live scans of fluorescent reporters in transgenic larvae. Although different references were used, the atlases included several common transgenic patterns that provide potential “bridges” for transforming each into the others coordinate space. We tested multiple bridging channels and registration algorithms and found that the symmetric diffeomorphic normalization algorithm improved live brain registration precision while better preserving cell morphology than B-spline-based registrations. Symmetric diffeomorphic normalization also corrected for tissue distortion introduced during fixation. Multi-reference channel optimization provided a transformation that enabled Z-Brain and ZBB to be co-aligned with precision of approximately a single cell diameter and minimal perturbation of cell and tissue morphology. Finally, we developed software to visualize brain regions in 3 dimensions, including a virtual reality neuroanatomy explorer. This study demonstrates the feasibility of integrating whole brain datasets, despite disparate reference templates and acquisition protocols, when sufficient information is present for bridging. Increased accuracy and interoperability of zebrafish digital brain atlases will facilitate neurobiological studies.

Multimedia mashups for mirror worlds

Mirror worlds are virtual worlds that reflect real world locations and events; they may be composed from many sources and exposed to support a wide variety of applications. Building mirror worlds requires the integration of several capabilities in both the content pipeline and the runtime. We describe two case studies to identify the elements of a formats content model are best suited for mirror world representation. The first one increases public accessibility for NOAAs Science On a Sphere®. The second involves the web-publication of geospatial data relating to Blacksburg, Virginia. Through these studies, we examine the challenges encountered, and the implications that those challenges have for an improved mirror world content models. Our results indicate that X3D is a powerful portrayal platform for mirror worlds, and we propose a few improvements that would address the challenges we encountered.

The effects of immersion and navigation on the acquisition of spatial knowledge of abstract data networks

Abstract With increasing frequency immersive virtual environments (IVEs) are being used to present multi-dimensional information visualizations. Networks and graphs are a common type of abstract data; in order to understand the varied relationships between entities in a network, it is crucial to acquire some spatial knowledge about the layout and connectivity of its components. While there is a good body of evidence for the benefits of IVE displays, most work on the effects of immersion and of navigation on the acquisition of spatial knowledge has been concerned with wayfinding in realistic environments; much less is known about how to leverage IVE technology to benefit a user’ss spatial understanding of (abstract) data networks. In this paper we present an empirical study designed to determine what effect level of immersion and navigation technique can have on a user’s acquisition of spatial knowledge of network data, specifically cell signaling pathways. For this CAVE study (CAVE Automatic Virtual Environment), the level of immersion is controlled by changing the Field-Of-Regard, while we also vary navigation between one egocentric and one exocentric technique. The results show that both immersion and navigation technique can affect the acquisition of spatial knowledge regarding abstract networks in an immersive virtual environment.

Future Standards for Immersive VR: Report on the IEEE Virtual Reality 2007 Workshop

The future standards for immersive VR workshop at the IEEE Virtual Reality 2007 Conference aimed to foster an understanding between the VR and Web3D communities. Although the fields of VR and Web-based 3D graphics tend to view their technologies as different beasts, the technologies share many requirements regarding virtual world content: modeling, lighting, animation, interaction, and direct manipulation. This workshop focused on the common interests around the seamless access and delivery of interactive, network-based VR content and resources.