Gerard Jounghyun Kim

A SWOT analysis of the field of virtual reality rehabilitation and therapy

The use of virtual-reality technology in the areas of rehabilitation and therapy continues to grow, with encouraging results being reported for applications that address human physical, cognitive, and psychological functioning. This article presents a SWOT (Strengths, Weaknesses, Opportunities, and Threats) analysis for the field of VR rehabilitation and therapy. The SWOT analysis is a commonly employed framework in the business world for analyzing the factors that influence a companys competitive position in the marketplace with an eye to the future. However, the SWOT framework can also be usefully applied outside of the pure business domain. A quick check on the Internet will turn up SWOT analyses for urban-renewal projects, career planning, website design, youth sports programs, and evaluation of academic research centers, and it becomes obvious that it can be usefully applied to assess and guide any organized human endeavor designed to accomplish a mission. It is hoped that this structured examination of the factors relevant to the current and future status of VR rehabilitation will provide a good overview of the key issues and concerns that are relevant for understanding and advancing this vital application area.

An object-oriented representation for product and design processes

Abstract We report on the development of a knowledge representation model, which is based on the SHARED object model reported in Shared Workspaces for Computer-Aided Collaborative Engineering (Wong, A. and Sriram, D., Technical Report, IESL 93-06, Intelligent Engineering Systems Laboratory, Department of Civil Engineering, MIT, March, 1993) and Research in Engineering Design (Wong, A. and Sriram, D., SHARED: An Information Model for Cooperative Product Development, 1993, Fall, 21-39). Our current model is implemented as a layered scheme, that incorporates both an evolving artifact and its associated design process. To represent artifacts as they evolve, we define objects recursively without a pre-defined granularity on this recursive decomposition. This eliminates the need for translations between levels of abstraction in the design process. The SHARED model extends traditional OOP in three ways: 1. by allowing explicit relationship classes with inheritance hierarchies; 2. by permitting constraints to be associated with objects and relationships; and 3. by comparing `similar objects at three different levels (form, function and behavior). nFive primitive objects define the design process: goal, plan, specification, decision and context. Goal objects achieve function, introduce constraints, introduce new artifacts or modify existing ones, and create subgoals. Plan objects order goals and link a product hierarchy to a process hierarchy. Specification objects define user inputs as constraints. Decision objects relate goals to user decisions and context objects describe the design context. Operators that are applied to design objects collectively form a representation of the design process for a given context. The representation is robust enough to effectively model four design paradigms [described in Journal of CAD (Gorti, S. and Sriram, R. D., Symbol to Form Mapping: a Framework for Conceptual Design, 1996, 28 (11), 853–870)]: top-down decomposition, step-wise refinement, bottom-up composition and constraint propagation. To demonstrate this, we represent the designs of two TV remote controllers in the SHARED architecture. The example reveals that certain aspects of artifact knowledge are essentially context-independent and that this representation can be a foundation for robust knowledge-based systems in design.

Haptic control of a mobile robot: a user study

We address the problem of teleoperating a mobile robot using shared autonomy: an on-board controller performs obstacle avoidance while the operator uses the manipulandum of a haptic probe to designate the desired speed and rate of turn. Sensors on the robot are used to measure obstacle range information. We describe a strategy to convert such range information into forces, which are reflected to the operators hand, via the haptic probe. This haptic information provides feedback to the operator in addition to imagery from a front-facing camera mounted on the mobile robot. Extensive experiments with a user population show that the added haptic feedback significantly improves operator performance in several ways (reduced collisions, increased minimum distance between the robot and obstacles) without a significant increase in navigation time.

Implementation and evaluation of just follow me: an immersive, VR-based, motion-training system

Training is usually regarded as one of the most natural application areas of virtual reality (VR). To date, most VR-based training systems have been situation based, but this paper examines the utility of VR for a different class of training: learning to execute exact motions, which are often required in sports and the arts. In this paper, we propose an interaction method, called Just Follow Me (JFM), that uses an intuitive ghost metaphor and a first-person viewpoint for effective motion training. Using the ghost metaphor (GM), JFM visualizes the motion of the trainer in real time as a ghost (initially superimposed on the trainee) that emerges from ones own body. The trainee who observes the motion from the first-person viewpoint follows the ghostly master as closely as possible to learn the motion. Our basic hypothesis is that such a VR system can help a student learn motion effectively and quickly, comparably to the indirect real-world teaching methods. Our evaluation results show that JFM produces training and transfer effects as good asand, in certain situations, better thanin the real world. We believe that this is due to the more direct and correct transfer of proprioceptive information from the trainer to the trainee.

Immersive authoring of tangible augmented reality applications

In this paper, we suggest a new approach for authoring tangible augmented reality applications, called immersive authoring. The approach allows the user to carry out the authoring tasks within the AR application being built, so that the development and testing of the application can be done concurrently throughout the development process. We describe the functionalities and the interaction design for the proposed authoring system that are specifically targeted for intuitive specification of scenes and various object behaviors. Several cases of applications developed using the authoring system are presented. A small pilot user study was conducted to compare the proposed method to a non-immersive approach, and the results have shown that the users generally found it easier and faster to carry out authoring tasks in the immersive environment.

Occlusion based interaction methods for tangible augmented reality environments

Traditional Tangible Augmented Reality (Tangible AR) interfaces combine a mixture of tangible user interface and augmented reality technology, complementing each other for novel interaction methods and real world anchored visualization. However, well known conventional one and two dimensional interaction methods such as pressing buttons, changing slider values, or menu selections are often quite difficult to apply to Tangible AR interfaces. In this paper we suggest a new approach, occlusion based interaction, in which visual occlusion of physical markers are used to provide intuitive two dimensional interaction in Tangible AR environments. We describe how to implement occlusion based interfaces for Tangible AR environments, give several examples of applications and describe results from informal user studies.

Haptic teleoperation of a mobile robot: a user study

The problem of teleoperating a mobile robot using shared autonomy is addressed: An onboard controller performs close-range obstacle avoidance while the operator uses the manipulandum of a haptic probe to designate the desired speed and rate of turn. Sensors on the robot are used to measure obstacle-range information. A strategy to convert such range information into forces is described, which are reflected to the operators hand via the haptic probe. This haptic information provides feedback to the operator in addition to imagery from a front-facing camera mounted on the mobile robot. Extensive experiments with a user population both in virtual and in real environments show that this added haptic feedback significantly improves operator performance, as well as presence, in several ways (reduced collisions, increased minimum distance between the robot and obstacles, etc.) without a significant increase in navigation time.

Design and evaluation of a wind display for virtual reality

One of the goals in the design of virtual environments (VE) is to give the user the feeling of existence within the VE, known as presence. Employing multimodality is one way to increase presence, and as such, numerous multimodal input and output devices have been used in the context of virtual reality (VR). However, the simulation and investigation into the effects of the wind (or air flow) has not been treated much in the VR research community. In this paper, we introduce a wind display system, called the WindCube, designed for virtual reality applications. The WindCube consists of a number of small fans attached to a cubical structure in which a VR system user interacts with the VE. We first discuss the design parameters of the proposed display device such as the type of the fan used, and the appropriate number, locations and directions of the fans in relation to providing the minimum level of the wind effects and enhanced presence. In order to simulate the effects of the wind, a wind field is first specified within the virtual environment. We describe how the specified wind field is rendered to the user through the proposed device. Finally, we investigate the effects of the proposed wind display to user felt presence through an experiment. It is our belief that wind display is very important and cost effective modality to consider and employ, because it involves air, a medium that makes the VE felt more livable, in contrast to many VEs that looks vaccum.

Modeling virtual object behavior within virtual environment

Development of virtual reality systems requires iterations of specification, implementation and evaluation. Since correct evaluations of immersive VR systems require the tedious process of wearing many devices, there exist both temporal and spatial gaps between the implementation and evaluation stage, and this usually causes delay and inefficiency in the development process. In order to overcome this gap, there have been several approaches to constructing or modeling the physical aspects of the virtual world (or objects) within the virtual environment. However, modeling their behaviors is still carried out in conventional (2D) programming environments.This paper proposes an interaction model, and interfaces for specifying (and modifying) object behavior, within the virtual environment, based on an underlying virtual object model. The interaction model follows the concept of programming by demonstration, and based on it, we have built a system called the PiP (Programming virtual object behavior in virtual reality Program) in which a user can create, modify, test, and save object behaviors. We illustrate examples of interactive virtual worlds constructed using the PiP, and discuss its merits and shortcomings as a content development platform.

Immersive authoring: What You eXperience Is What You Get (WYXIWYG)

Users experience and verify immersive content firsthand while creating it within the same virtual environment.