We analyze carefully the problem of gauge symmetries for Bianchi models, from both the geometrical and dynamical points of view. Some of the geometrical definitions of gauge symmetries (=“homogeneity preserving diffeomorphisms”) given in the literature do not incorporate the crucial feature that local gauge transformations should be independent at each point of the manifold of the independent v...

Geometrical transformations are one of the most important issues to be solved to increase the robustness of digital image watermarking systems. This paper presents an efficient method for inverting geometrical distortions that may spatially desynchronise a watermark detector. We propose a strategy that is scalable in transform complexity, since in some cases a simple transformation is sufficien...

From a technological point of view, reciprocal structures have the advantage of simplifying considerably connections in the sense that members are connected only by pairs. This constructional advantage has two main consequences: technological constrains are replaced by geometrical constrains and bending moments are increased through the non convergence of members to nodes with multiple connecti...

Current algorithms for imaging seismic reflection data can be subdivided into two classes: Kirchhoff (generalized Radon transform) and wave-equation (double-square-root and reverse-time) migration. Kirchhoff type methods rely on asymptotic and ray-geometrical considerations. Wave-equation imaging algorithms (one-way or twoway) appear to be more robust in the case of complicated velocity models ...

the resonant frequency and sensitivity of an atomic force microscope (afm) cantilever with assembled cantilever probe (acp) have been analyzed and a closed-form expression for the sensitivity of vibration modes has been obtained. the proposed acp comprises an inclined cantilever and extension, and a tip located at the free end of the extension, which makes the afm capable of topography at sidew...

We present in this communication a new method to localize a face in an image. The originality of work presented consists on the use of vectors of geometrical moments like entries to a Forward BackPropagation neural network which provide at its output layer a vector of co-ordinates in (R,θ) representing pixels surrounding the face contained in the treated image. Very known for their orthogonalit...

The most widespread approach to anisotropic media is dyadic analysis. However, to get a geometrical picture of a dielectric tensor, one has to resort to a coordinate system for a matrix form in order to obtain, for example, the index-ellipsoid, thereby obnubilating the deeper coordinate-free meaning of anisotropy itself. To overcome these shortcomings we present a novel approach to anisotropy: ...

We are here dealing with the problem of space layout planning. We present an approach based on an intermediate topological level with dynamic space ordering (dso) heuristics. Our software ARCHiPLAN proceeds through a number of steps. First, all the topologically different solutions, without presuming any precise dimension, are enumerated. Next, we may evolve in this topological solution space, ...

In order to reduce the dipole wake encountered by the first few bunches accelerated in a multi-bunch NLC scenario the DDS (damped detuned structure) was re-designed such that a much improved Gaussian fall-off occurs in the initial wake-function. From the 9 parameterised model of DDS1 we use a mapping function to allow DDS 3 & 4 to be modeled and hence avoid additional and prohibitively time con...

We derive the basic principles of Electromagnetism and general relativity from a common (geometrical) starting formulation we call START, from its geometrical structure as a Space– Time–Action Relativity Theory. Gravitation results from the epistemological approach of defining a test particle which explores the physical world in such a form that its trajectory indicates the influence of the res...