Results 1 - 10 of 3,630

Least squares quantization in pcm.

by Stuart P Lloyd - Bell Telephone Laboratories Paper , 1982
"... Abstract-It has long been realized that in pulse-code modulation (PCM), with a given ensemble of signals to handle, the quantum values should be spaced more closely in the voltage regions where the signal amplitude is more likely to fall. It has been shown by Panter and Dite that, in the limit as t ..."
Abstract - Cited by 1362 (0 self) - Add to MetaCart
Abstract-It has long been realized that in pulse-code modulation (PCM), with a given ensemble of signals to handle, the quantum values should be spaced more closely in the voltage regions where the signal amplitude is more likely to fall. It has been shown by Panter and Dite that, in the limit

Image denoising using a scale mixture of Gaussians in the wavelet domain

by Javier Portilla, Vasily Strela, Martin J. Wainwright, Eero P. Simoncelli - IEEE TRANS IMAGE PROCESSING , 2003
"... We describe a method for removing noise from digital images, based on a statistical model of the coefficients of an overcomplete multiscale oriented basis. Neighborhoods of coefficients at adjacent positions and scales are modeled as the product of two independent random variables: a Gaussian vecto ..."
Abstract - Cited by 513 (17 self) - Add to MetaCart
vector and a hidden positive scalar multiplier. The latter modulates the local variance of the coefficients in the neighborhood, and is thus able to account for the empirically observed correlation between the coefficient amplitudes. Under this model, the Bayesian least squares estimate of each

Quantum amplitude amplification and estimation

by Gilles Brassard, Peter Høyer, Michele Mosca , 2002
"... Abstract. Consider a Boolean function χ: X → {0, 1} that partitions set X between its good and bad elements, where x is good if χ(x) = 1 and bad otherwise. Consider also a quantum algorithm A such that A|0 〉 = � x∈X αx|x 〉 is a quantum superposition of the elements of X, and let a denote the proba ..."
Abstract - Cited by 174 (14 self) - Add to MetaCart
the probability that a good element is produced if A|0 〉 is measured. If we repeat the process of running A, measuring the output, and using χ to check the validity of the result, we shall expect to repeat 1/a times on the average before a solution is found. Amplitude amplification is a process that allows

Global Spontaneous Activity and Local Structured (learned) Delay Activity in Cortex

by Daniel J. Amit, La Sapienza, Ple Aldo Moro, Nicolas Brunel, Universita Di Roma, Universita Di Roma , 1996
"... to any of the stimuli learned have rates which gradually increase with the amplitude of synaptic potentiation. b. When the average LTP increases beyond a critical value, specific local attractors appear abruptly against the background of the global uniform spontaneous attractor. This happens with e ..."
Abstract - Cited by 306 (26 self) - Add to MetaCart
to any of the stimuli learned have rates which gradually increase with the amplitude of synaptic potentiation. b. When the average LTP increases beyond a critical value, specific local attractors appear abruptly against the background of the global uniform spontaneous attractor. This happens

Averaging bounds for lattices and linear codes

by Hans-andrea Loeliger - IEEE Trans. Information Theory , 1997
"... Abstract — General random coding theorems for lattices are derived from the Minkowski–Hlawka theorem and their close relation to standard averaging arguments for linear codes over finite fields is pointed out. A new version of the Minkowski–Hlawka theorem itself is obtained as the limit, for p!1,ofa ..."
Abstract - Cited by 99 (1 self) - Add to MetaCart
Abstract — General random coding theorems for lattices are derived from the Minkowski–Hlawka theorem and their close relation to standard averaging arguments for linear codes over finite fields is pointed out. A new version of the Minkowski–Hlawka theorem itself is obtained as the limit, for p!1

MKPH-T-96-20 Generalized

by D. Drechsel, G. Knöchlein, A. Metz, S. Scherer , 1996
"... polarizabilities and the spin-averaged amplitude in virtual Compton scattering off the nucleon ..."
Abstract - Add to MetaCart
polarizabilities and the spin-averaged amplitude in virtual Compton scattering off the nucleon

Generalized Grover Search algorithm for arbitrary initial amplitude distribution

by David Biron, Ofer Biham, Eli Biham, Markus Grassl, Daniel A. Lidar - Proc. of the 1st NASA International Conference on Quantum Computing & Quantum Communications , 1998
"... Abstract. Grover’s algorithm for quantum searching of a database is generalized to deal with arbitrary initial amplitude distributions. First order linear difference equations are found for the time evolution of the amplitudes of the r marked and N −r unmarked states. These equations are solved exac ..."
Abstract - Cited by 32 (0 self) - Add to MetaCart
exactly. An expression for the optimal measurement time T ∼ O ( √ N/r) is derived which is shown to depend only on the initial average amplitudes of the marked and unmarked states. A bound on the probability of measuring a marked state is derived, which depends only on the standard deviation

Modification of empirical strong ground motion attenuation relations to include the amplitude and duration effects of rupture directivity

by Paul G. Somerville, Nancy F. Smith, Robert W. Graves, Norman A. Abrahamson , 1997
"... Rupture directivity effects cause spatial variations in ground motion amplitude and duration around faults and cause dif-ferences between the strike-normal nd strike-parallel com-ponents of horizontal ground motion amplitudes, which also have spatial variation around the fault. These variations beco ..."
Abstract - Cited by 100 (8 self) - Add to MetaCart
Rupture directivity effects cause spatial variations in ground motion amplitude and duration around faults and cause dif-ferences between the strike-normal nd strike-parallel com-ponents of horizontal ground motion amplitudes, which also have spatial variation around the fault. These variations

Peak to Average Power Reduction Using Amplitude and Sign Adjustment

by Masoud Sharif, Cedric Florens, Maryam Fazel, Babak Hassibi
"... Abstract — In this paper, we propose a method to reduce the peak to mean envelope power ratio (PMEPR) of multicarrier signals by modifying the constellation. For MPSK constellations, we minimize the maximum of the multicarrier signal over the sign and amplitude of each subcarrier. In order to find a ..."
Abstract - Add to MetaCart
the amplitude of each subcarrier can be written as a convex optimization problem with linear matrix inequality constraints. We also generalize the idea to other constellations such as 16QAM. Simulation results show that by an average power increase of 0.21 db and not sending information over the sign of each

Impact of network activity on the integrative properties of neocortical pyramidal neurons in vivo

by Alain Destexhe, Denis Paré - J. NEUROPHYSIOL. 81: 1531–1547, 1999 , 1999
"... During wakefulness, neocortical neurons are subjected to an intense synaptic bombardment. To assess the consequences of this background activity for the integrative properties of pyramidal neurons, we constrained biophysical models with in vivo intracellular data obtained in anesthetized cats duri ..."
Abstract - Cited by 163 (20 self) - Add to MetaCart
increase in the amplitude of V m fluctuations, as determined by comparing the same cells before and after microperfusion of tetrodotoxin (TTX). The model was constrained by measurements of R in, by the average value and standard deviation of the V m measured from epochs of intense synaptic activity
Results 1 - 10 of 3,630