G. Drew Kessler

Virtual reality exposure therapy in the treatment of fear of flying: a case report

The efficacy of virtual reality (VR) exposure therapy was examined for the fear of flying. Virtual reality exposure involved six sessions of graded exposure to flying in a virtual airplane. The specific contribution of anxiety management techniques (AMT) and the VR exposure was examined in a single case design. The subject was a 42-year-old female with a debilitating fear and avoidance of flying. All self-report measures of the fear and avoidance of flying decreased following AMT and decreased still further following VR exposure. A planned post-treatment flight was completed with anxiety measures indicating comfortable flight. The implications of this new medium for exposure therapy are discussed.

Evaluation of the CyberGlove as a whole-hand input device

We present a careful evaluation of the sensory characteristics of the CyberGlove model CG1801 whole-hand input device. In particular, we conducted an experimental study that investigated the level of sensitivity of the sensors, their performance in recognizing angles, and factors that affected accuracy of recognition of flexion measurements. Among our results, we show that hand size differences among the subjects of the study did not have a statistical effect on the accuracy of the device. We also analyzed the effect of different software calibration approaches on accuracy of the sensors.

The Simple Virtual Environment Library: An Extensible Framework for Building VE Applications

As virtual environment (VE) technology becomes accessible to (and affordable for) an ever-widening audience of users, the demand for VE applications will increase. Tools that assist and facilitate the development of these applications, therefore, will also be in demand. To support our efforts in quickly designing and implementing VE applications, we have developed the Simple Virtual Environment (SVE) library. In this article, we describe the characteristics of the library that support the development of both simple and complex VE applications. Simple applications are created by novice programmers or for rapid prototyping. More-complex applications incorporate new user input and output devices, as well as new techniques for user interaction, rendering, or animation. The SVE library provides more-comprehensive support for developing new VE applications and better supports the various device configurations of VE applications than current systems for 3-D graphical applications. The development of simple VE applications is supported through provided default interaction, rendering, and user input and output device handling. The librarys framework includes an execution framework that provides structure for incrementally adding complexity to selected tasks of an application, and an environment model that provides a layer of abstraction between the application and the device configuration actually used at runtime. This design supports rapid development of VE applications through incremental development, code reuse, and independence from hardware resources during the development.

Concurrency control mechanisms for closely coupled collaboration in multithreaded peer-to-peer virtual environments

As collaboration in virtual environments becomes more object-focused and closely coupled, the frequency of conflicts in accessing shared objects can increase. In addition, two kinds of concurrency control surprises become more disruptive to the collaboration. Undo surprises can occur when a previously visible change is undone because of an access conflict. Intention surprises can happen when a concurrent action by a remote session changes the structure of a shared object at the same perceived time as a local access of that object, such that the local user might not get what they expect because they have not had time to visually process the change. A hierarchy of three concurrency control mechanisms is presented in descending order of collaborative surprises, which allows the concurrency scheme to be tailored to the tolerance for such surprises. One mechanism is semioptimistic; the other two are pessimistic. Designed for peer-to-peer virtual environments in which several threads have access to the shared scene graph, these algorithms are straightforward and relatively simple. They can be implemented using C/C++ and Java, under Windows and Unix, on both desktop and immersive systems. In a series of usability experiments, the average performance of the most conservative concurrency control mechanism on a local LAN was found to be quite acceptable.

DEMIS: a dynamic event model for interactive systems

Modern interaction systems are usually event-driven. New input devices often require new event types, and handling input from the user becomes increasingly more complex. Frequently, the WIMP (Windows, Icons, Menus, Pointer) paradigm widely used today is not suitable for interactive applications, such a virtual reality applications, that use more than the standard mouse and keyboard input devices.In this paper, we present the design and implementation of the Dynamic Event Model for Interactive System (DEMIS). DEMIS is a middleware between the operating system and the application that supports various input device events while using generic event recognition to detect composite events.

GroupMorph:: a group collaboration mode approach to shared 3D virtual environments for product design

Virtual reality technology is increasingly being applied to globally distributed teams engaged in collaborative product design. Observations of product design teams have suggested at least four distinct modes of collaboration-complementary, competitive, peer-to-peer, and leader-follower. Another insight from observation is that collaboration consists of fluid transitions between these modes in the accomplishment completion of the design task, driven by a flexible process of subgrouping and regrouping which reflects the structure and progress of the task. Yet most collaborative virtual environment systems support only one mode of collaboration-peer-to-peer-and those that do explicitly support multiple modes (or even individual roles) do not allow fluid transitions between them in the context of the same task. In addition, no explicit support is provided to allow subgroups to be formed and dissolved. To address this problem, a collaborative virtual environment (CVE) for product design that supports multiple collaboration modes and fluid transitions is proposed; two metaphors for collaborative product design (collaboration tree and infinitely recursive conference room) are introduced; the use of a collaboration tree interface widget is detailed; and the Simple Shared Virtual Environment (SSVE) toolkit for collaborative virtual environments is described.