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...

Instantaneous frequency-slowness method (IFS) is based on complex wave form analysis. It delivers the same measures as complex wave form method e.g. slowness and standard deviation, goodness of the data and receiver responses across the neighbouring pairs. Additionally, IFS method computes instantaneous frequency and slowness wave forms as seen between adjacent receivers. Classic semblance meth...

[1] Seismic phases diffracted around Earth’s core contain information about lowermost mantle wave speeds. By measuring the slowness of incident diffracted energy from array recordings, seismic velocity along the diffracted path can be estimated. Here we apply this principle to diffraction of the major arc seismic phase PKKPab recorded at the Canadian Yellowknife array to estimate P wave velocit...

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...

The seismic arrays of the International Monitoring System (IMS) for the Comprehensive Nuclear-Test-Ban Treaty (CTBT) are highly diverse in size and configuration, with apertures ranging from under 1 km to over 60 km. Large and medium aperture arrays with large inter-site spacings complicate the detection and estimation of high-frequency phases lacking coherence between sensors. Pipeline detecti...

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 ...