Adaptivity in Virtual Environments: Enhancing User Interaction and Accommodating User Diversity

Abstract

Virtual environments are highly interactive, computer-simulated environments where users interact in 3D spaces to performcomplex tasks using diverse 3D interaction techniques and devices. The complexity of 3D interaction in virtual environments may hinder user interaction and influence user performance. User interaction in virtual environments may also be restrained by the variety between the users due to the different user characteristics, which are seldom taken into account when designing virtual environments. This dissertation is motivated by our belief that providing adaptivity in virtual environments is a significant key to enhance user interaction and accommodate user diversity. Our research is directed to strive for the integration of adaptivity into virtual environments and investigate to what extent the integrated adaptivity can enhance natural and intuitive user interaction. The first part of this dissertation is dedicated to investigate adaptation in virtual environments in general since it has not been extensively explored in any previous research. We present an overview of adaptation in virtual environments including several types of adaptation that can be provided and a research framework to enable the integration of such adaptation. A number of formal experiments show that integrating adaptation in a virtual environment leads to improved interaction, performance increase, frustration decrease and positive appreciation from the users. The second part of this dissertation focuses in exploring adaptivity in virtual environments specifically designed for upper-limb rehabilitation of people with Multiple Sclerosis (MS). The user studies carried out with MS patients demonstrate the potential benefits of providing an adaptive personalized training in their rehabilitation. We hope that a contemplation on this dissertation would increase a conscious awareness of designers and developers of virtual environments towards the user diversity and the necessity of integrating adaptivity to enhance user interaction.