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Investigating virtual environments has become an increasingly interesting research topic for engineers, computer and cognitive scientists, and psychologists. Although there have been several recent studies focused on the development of multimodal virtual environments (VEs) to study human-machine interactions, less attention has been paid to human-human and(More)
Computer haptics, an emerging field of research that is analogous to computer graphics , is concerned with the generation and rendering of haptic virtual objects. In this paper, we propose an efficient haptic rendering method for displaying the feel of 3-D polyhedral objects in virtual environments (VEs). Using this method and a haptic interface device, the(More)
The main focus of the present investigation is the development of quantitative measures to assess the dynamic stability of human locomotion. The analytical methodology is based on Floquet theory, which was developed to investigate the stability of nonlinear oscillators. Here the basic approach is modified such that it accommodates the study of the complex(More)
Haptics is a valuable tool in minimally invasive surgical simulation and training. We discuss important aspects of haptics in MISST, such as haptic rendering and haptic recording and playback. Minimally invasive surgery has revolutionized many surgical procedures over the last few decades. MIS is performed using a small video camera, a video display, and a(More)
The study reported in this article was conducted to propose a set graphical and analytical tools and assess their clinical utility by analyzing gait kinematics and dynamics of polio survivors. Phase-plane portraits and first return maps were used as graphical tools to detect abnormal patterns in the sagittal kinematics of post-polio gait. Two new scalar(More)
Additional graphical tools are needed to better visualize the joint kinematics of human locomotion. Standard plots in which the joint displacements are plotted against time or percent gait cycle do not provide sufficient information about the dynamics of the system. In this article, a study based on the two graphical tools of nonlinear dynamics to visualize(More)
We report the manipulation of 4-5 mum diameter polymer microspheres floating in water using optical tweezers (OT) and a haptic device (i.e. force-reflecting robotic arm). Trapped microspheres are steered using the end-effector of a haptic device that is virtually coupled to an XYZ piezo-scanner controlling the movements of the fluid bed. To help with the(More)
A new approach, called adaptive Q control, for tapping-mode atomic force microscopy (AFM) is introduced and implemented on a homemade AFM setup utilizing a laser Doppler vibrometer and a piezoactuated bimorph probe. In standard Q control, the effective Q factor of the scanning probe is adjusted prior to the scanning depending on the application. However,(More)