An Arm-Mounted Accelerometer and Gyro-Based 3D Control System

This thesis examines the performance of a wearable accelerometer/gyroscope-based system for capturing arm motions in 3D. Two experiments conforming to ISO 9241-9 specifications for non-keyboard input devices were performed. The first, modeled after the Fitts' law paradigm described in ISO 9241-9, utilized the wearable system to control a telemanipulator compared with joystick control and the user's arm. The throughputs were 5.54 bits/s, 0.74 bits/s and 0.80 bits/s, respectively. The second experiment utilized the wearable system to control a cursor in a 3D fish-tank virtual reality setup. The participants performed a 3D Fitts' law task with three selection methods: button clicks, dwell, and a twist gesture. Error rates were 6.82 %, 0.00% and 3.59 % respectively. Throughput ranged from 0.8 to 1.0 bits/s. The thesis includes detailed analyses on lag and other issues that present user interface challenges for systems that employ human-mounted sensor inputs to control a telemanipulator apparatus

Performance Factors in Neurosurgical Simulation and Augmented Reality Image Guidance

Virtual reality surgical simulators have seen widespread adoption in an effort to provide safe, cost-effective and realistic practice of surgical skills. However, the majority of these simulators focus on training low-level technical skills, providing only prototypical surgical cases. For many complex procedures, this approach is deficient in representing anatomical variations that present clinically, failing to challenge users’ higher-level cognitive skills important for navigation and targeting. Surgical simulators offer the means to not only simulate any case conceivable, but to test novel approaches and examine factors that influence performance. Unfortunately, there is a void in the literature surrounding these questions. This thesis was motivated by the need to expand the role of surgical simulators to provide users with clinically relevant scenarios and evaluate human performance in relation to image guidance technologies, patient-specific anatomy, and cognitive abilities. To this end, various tools and methodologies were developed to examine cognitive abilities and knowledge, simulate procedures, and guide complex interventions all within a neurosurgical context. The first chapter provides an introduction to the material. The second chapter describes the development and evaluation of a virtual anatomical training and examination tool. The results suggest that learning occurs and that spatial reasoning ability is an important performance predictor, but subordinate to anatomical knowledge. The third chapter outlines development of automation tools to enable efficient simulation studies and data management. In the fourth chapter, subjects perform abstract targeting tasks on ellipsoid targets with and without augmented reality guidance. While the guidance tool improved accuracy, performance with the tool was strongly tied to target depth estimation – an important consideration for implementation and training with similar guidance tools. In the fifth chapter, neurosurgically experienced subjects were recruited to perform simulated ventriculostomies. Results showed anatomical variations influence performance and could impact outcome. Augmented reality guidance showed no marked improvement in performance, but exhibited a mild learning curve, indicating that additional training may be warranted. The final chapter summarizes the work presented. Our results and novel evaluative methodologies lay the groundwork for further investigation into simulators as versatile research tools to explore performance factors in simulated surgical procedures

Human-computer interaction in ubiquitous computing environments

Purpose &ndash; The purpose of this paper is to explore characteristics of human-computer interaction when the human body and its movements become input for interaction and interface control in pervasive computing settings. Design/methodology/approach &ndash; The paper quantifies the performance of human movement based on Fitt\u27s Law and discusses some of the human factors and technical considerations that arise in trying to use human body movements as an input medium. Findings &ndash; The paper finds that new interaction technologies utilising human movements may provide more flexible, naturalistic interfaces and support the ubiquitous or pervasive computing paradigm. Practical implications &ndash; In pervasive computing environments the challenge is to create intuitive and user-friendly interfaces. Application domains that may utilize human body movements as input are surveyed here and the paper addresses issues such as culture, privacy, security and ethics raised by movement of a user\u27s body-based interaction styles. Originality/value &ndash; The paper describes the utilization of human body movements as input for interaction and interface control in pervasive computing settings. <br /

Interface design to support situation awareness in virtual puppetry

Virtual Heritage is the use of digital media to reconstruct cultures and cultural artifacts as they are today or as they might have been in the past. The central element is usually a threedimensional computer model of a person, place, or thing. Frequently, these are ancient monuments, temples, homes, and other social spaces (Jacobson, 2008). The goal of Virtual Heritage is to draw viewers into the virtual world and allow them to directly experience the overall context of the environment. This phenomenon is known to researchers as “presence.” It is a long held belief that the increased presence yields better the opportunities for deeper learning (Devine, 2007)