Tomography refers to the technique of reconstructing a field from line or surface integrals of it. In medical X-ray tomography, for example, the tissue density field is deduced from measurements of X-ray attenuation through the patient. In this case the data are regularly sampled line integrals, so they are discrete values of a Radon transform. In seismology, the determination of slowness (inve...

AIMS To investigate the ability of patients with Parkinson's disease to perform a rotation around the longitudinal axis of the body. Three questions were raised. Is body rotation impaired in Parkinson's disease? Is there a level of the kinematic chain from the head to the foot at which the impairment is more severe? Is the deficit related to the general slowness of movement in Parkinson's disea...

S U M M A R Y We propose a level-set adjoint-state method for crosswell traveltime tomography using both first-arrival transmission and reflection traveltime data. Since our entire formulation is based on solving eikonal and advection equations on finite-difference meshes, our traveltime tomography strategy is carried out without computing rays explicitly. We incorporate reflection traveltime d...

We studied 10 subjects each with melancholic depression evidencing significant motor retardation (RM), Parkinson's disease (PD) with bradykinesia, and normal healthy controls (NC), matched closely for age and gender, on measurements of motor function and depression, and their performance of simple and complex ballistic movements. The simple movements involved the execution of 10 degrees, 20 deg...

Slowness in robotic systems is a quality that is typically undervalued. It is our contention that as slowness has utility in animal behavior in certain species that it may also provide useful qualities for robotic implementations in appropriate circumstances. In particular we study mammalian behavior as evidenced in the tree sloth and slow Loris as the basis for the behaviors of a robot capable...

In this report, we introduce a new wave-equation method of migration velocity analysis (MVA). The method is based on the linear relation that can be established between a perturbation in the migrated image and the generating perturbation in the slowness function. Our method consists of two steps: we first improve the focusing of the migrated image and then iteratively update the velocity model ...

In contrast to the equivalence of linear blind source separation and linear independent component analysis it is not possible to recover the original source signal from some unknown nonlinear transformations of the sources using only the independence assumption. Integrating the objectives of statistical independence and temporal slowness removes this indeterminacy leading to a new method for no...