Echo-planar images acquired in nonaxial planes are often distorted. Such image distortion has limited the applications of the echo-planar imaging (EPI) technique. In this article, it is demonstrated that a considerable amount of the distortion is caused by the higher-order magnetic field concomitant with the linear magnetic field gradient, or the concomitant magnetic field. The image distortion...

Peculiar velocities induce apparent line of sight displacements of galaxies in redshift space, distorting the pattern of clustering. On large scales, the amplitude of the distortion yields a measure of the dimensionless linear growth rate β ≈ Ω/b of fluctuations, where Ω if the cosmological density and b is the bias factor. To make the maximum statistical use of the data in a wide-angle redshif...

The use of High Power Amplifiers (HPA) in digital communications is plagued with non-linear (AM/AM and AM/PM) distortion. This is specially acute for those modulations that are not constant amplitude, such as OFDM or MQAM. We present a pre-distortion algorithm that, in contrast to previously researched architectures, is unconditionally convergent.

This paper presents a Rate-Distortion analysis for a simple horizon edge image model. A quadtree with anisotropy and rotation is performed on this kind of image, giving a toy model for a non-linear adaptive coding technique, and its Rate-Distortion behavior is studied. The effect of refining the quadtree decomposition is also analyzed.

This work presents a substantial improvement of the variables’ inclusion and interchange algorithm (VIIA) for capacitors placement that considers circuits with harmonic distortion. Several load states are considered, fixed switched employed in optimization. All pertinent constraints voltage magnitude, total distortion, individual overstress implemented. The here defined global harmonic-distorti...

Achievable distortion bounds are derived for the cascade of structured families of binary linear channel codes and binary lattice vector quantizers. It is known that for the cascade of asymptotically good channel codes and asymptotically good vector quantizers the end-to-end distortion decays to zero exponentially fast as a function of the overall transmission rate, and is achieved by choosing ...

to measure an unbiased farm-specific efficiency of individual dairy farmers, a shadow-price profit frontier adjusted for market distortion was applied to a sample of 860 iranian small intensive dairy farms surveyed in 2005-2006. this measure was then compared with that of unadjusted measure that assumes undistorted market. a multiple general linear model (glm) technique was applied to the data ...

This paper uses an analysis of Speeded up Robust Feature (SURF), based on the method of Linear Interpolation for camera distortion calibration, for high-density crowd counting. The eigenvalues are built on the Gray Level Co-occurrence Matrix (GLCM) features and the SURF features. Through the method of linear interpolation, weight values are interpolated to reduce the error, which is caused by c...

The rapid increase of non-linear loads in the last three decades has caused electrical quantities such as voltages and currents in 3-phase distribution systems to become distorted waveforms. This paper reviews, explains and discusses some new concepts, definitions and new available theory in the unbalanced and distorted systems. The usefulness of the proposed practical definitions is investigat...

We develop new rate distortion bounds for narrowband and wideband speech coding based on composite source models for speech and perceptual PESQ-MOS/WPESQ distortion measures. It is shown that these new rate distortion bounds do in fact lower bound the performance of important standardized speech codecs, including, G.726, G.727, AMR-NB, G.729, G.718, G.722, G.722.1, and AMR-WB. The approach is t...