When we find our way in the environment, we need to integrate information about location, direction and distance into a coherent map-like representation. Our work over the last 10 years has suggested that the medial entorhinal cortex plays a central role in this process. A key component of the entorhinal network for spatial mapping is the grid cell, which we discovered, together with our collea...

Medical image data is usually represented by a uniformly spaced grid of voxels. However, CT scanners for example are capable of producing non-uniformly spaced slice images. This is desirable when for a particular patient some regions (lesions) need to be imaged with a high resolution, while a lower resolution would be sufficient in other areas. Such an adaptive slice spacing can significantly r...

Three dimensional grid phantoms offer a number of advantages for measuring imaging related spatial inaccuracies for image guided surgery and radiotherapy. The authors examined the use of rapid prototyping technology for directly fabricating 3D grid phantoms from CAD drawings. We tested three different fabrication process materials, photopolymer jet with acrylic resin (PJ/AR), selective laser si...

A simple approach for mobile robots to exploit multipath fading in order to improve received radio signal strength (RSS), is presented. The strategy is to sample the RSS at discrete points, without deviating too far from the desired position. We first solve the problem of how many samples are needed for given communications performance and how they should be spaced. Second, we propose a circula...

Daubechies, Guskov, and Sweldens studied four-point, cubic-based interpolatory subdivision on irregularly spaced grid points and showed that if a ‘dyadic’ mesh-ratio, λ, where 1/2 ≤ λ ≤ 1, satisfies the bound λ ≤ 2/3, the limit function has Holder regularity C2− for any small > 0. They also conjectured that C2− regularity is maintained for all λ < 1. We show, on the contrary, that for certain g...

When searching for new gravitational-wave or electromagnetic sources, the $n$ signal parameters (masses, sky location, frequencies,...) are unknown. In practice, one hunts signals at a discrete set of points in parameter space, called template bank. These may be constructed systematically as lattice, alternatively, by placing templates randomly selected space. Here, we calculate fraction lost a...

The effects of using both directions and directional subdividing on adaptive gridembedding on the computational time and the number of grid points required for the same accuracy are considered. Directional subdividing is used from the beginning of the adaptation procedure without any restriction. To avoid the complication of unstructured grid, the semi-structured grid was used. It is used to so...