The use of haptic virtual fixtures is a potential tool to improve the safety of robotic and telerobotic surgery. They can “push back” on the surgeon to prevent unintended surgical tool movements into protected zones. Previous work has suggested generating virtual fixtures from preoperative images like CT scans. However these are difficult to establish and register in dynamic environments. This ...

Recently, according to the advanced hardware technology, the price of sensors in HMD (Head Mounted Display) is getting cheaper and calculation speed in smartphone is fast enough to express a plausible virtual reality. Users wear the HMD device on their head and it shows the virtual scenes in front of users. Users can enjoy a wide display without any restrictions in space. Based on this device, ...

In this paper we discuss direct interaction metaphors for selection and manipulation of distant objects in immersive virtual environments and we propose extensions of the improved virtual pointer (IVP) metaphor. In particular, we describe how the process of object selection with the IVP metaphor can be enhanced by modifying the distance calculation used to determine the closest object to be sel...

Aimed to develop a virtual robot aided surgery system which can represent the reality surgery process and realize force feedback by digital human tissue biomechanical information and outer force feedback instrument, human tissue geometrical and biomechanical modeling, biomechanical model calculation, force feedback instrument design, control algorithm are described. Finally, experiment was cond...

Optimistic protocols designed for Parallel Discrete Event Simulation (PDES) rely heavily on the Global Virtual Time (GVT) calculation. Since the simulation uses large amounts of memory , the GVT is used to synchronize processes and discard obsolete system information. In this paper we present a new algorithm, the Continuously Monitored Global Virtual Time (CMGVT). Unlike others, this algorithm ...

In many computer graphics applications it is desirable to augment the virtual objects with high dynamic range images representing a real environment. In order to provide the illusion that the virtual objects are parts of the real scene, the illumination of the environment should be taken into account when the virtual objects are rendered. Proper calculation of the illumination from an environme...

Previous studies have reported a similar duration for movement execution (real movement) and its internal simulation with motor imagery (virtual movement). The present work has studied the real movement-virtual movement relationship for complex sequences of finger movements after different acute and chronic brain lesions and after a long-lasting restriction of right-hand movements. Age, hand-mo...

This paper considers the problem of distributing data and code among the processors of a distributed memory supercomputer. Provided that the source program is amenable to detailed dataaow analysis, one may determine a placement function by an algorithm analogous to Gaussian elimination. Such a function completely characterizes the distribution by giving the identity of the virtual processor on ...

BACKGROUND Central to the design of a randomised controlled trial is the calculation of the number of participants needed. This is typically achieved by specifying a target difference and calculating the corresponding sample size, which provides reassurance that the trial will have the required statistical power (at the planned statistical significance level) to identify whether a difference of...

Recently, we evaluated the virtual cross-section for Bhabha scattering in pure QED, up to corrections of order α 4 (N F = 1). This calculation is valid for arbitrary values of the squared center of mass energy s and momentum transfer t; the electron and positron mass m was considered a finite, non vanishing quantity. In the present work, we supplement the previous calculation by considering the...