36 results about "Correlogram" patented technology

Apparatus and methods for plasticity in spiking neuron network. The network may comprise feature-specific units capable of responding to different objects (red and green color). Plasticity mechanism may be configured based on difference between two similarity measures related to activity of different unit types obtained during network training. One similarity measure may be based on activity of units of the same type (red). Another similarity measure may be based on activity of units of one type (red) and another type (green). Similarity measures may comprise a cross-correlogram and / or mutual information determined over an activity window. Several similarity estimates, corresponding to different unit-to-unit pairs may be combined. The combination may comprise a weighted average. During network operation, the activity based plasticity mechanism may be used to potentiate connections between units of the same type (red-red). The plasticity mechanism may be used to depress connections between units of different types (red-green).

Apparatus and methods for salient feature detection by a spiking neuron network. The network may comprise feature-specific units capable of responding to different objects (red and green color). The plasticity mechanism of the network may be configured based on difference between two similarity measures related to activity of different unit types obtained during network training. One similarity measure may be based on activity of units of the same type (red). Another similarity measure may be based on activity of units of one type (red) and another type (green). Similarity measures may comprise a cross-correlogram and / or mutual information determined over an activity window. During network operation, the activity based plasticity mechanism may be used to potentiate connections between units of the same type (red-red). The plasticity mechanism may be used to depress connections between units of different types (red-green). The plasticity mechanism may effectuate detection of salient features in the input.

Apparatus and methods for plasticity in a spiking neuron network. In one implementation, a plasticity mechanism is configured based on a similarity measure between neuron post-synaptic and pre-synaptic activity. The similarity measure may comprise a cross-correlogram between the output spike train and input spike train, determined over a plasticity window. Several correlograms, corresponding to individual input connections delivering pre-synaptic input, may be combined. The combination may comprise for example a weighted average. The averaged correlograms may be used to construct the long term potentiation component of the plasticity. The long term depression component of the plasticity may comprise e.g., a monotonic function based on a statistical parameter associated with the adaptively determined long term potentiation component.

Heterodyne interferometry is combined with spectrally-controlled interferometry (SCI) to achieve the advantages of both. Phase shifts produced by SCI produce phase-shifted correlograms suitable for heterodyne interferometric analysis, thereby enabling interferometric measurements with conventional common-path apparatus free of coherence noise and scanning-related errors, and with the precision of conventional heterodyne interferometry. A spectrum-modulating light source suitable for the invention is obtained by combining a rotating spiral grating with a multi-slit grating placed in the front focal plane of a collimating lens that propagates the light toward a blazed diffraction grating. Another exemplary spectrum-modulating light source is obtained by combining a slit spectrometer with an acousto-optic modulator.

A method, system and computer program product for adaptive system monitoring. In one embodiment, the method comprises generating time-varying correlation graphs indicating correlations between a multitude of parameters of the system, and using the correlation graphs to identify monitoring logic for monitoring the system. In an embodiment, the correlation graphs are used to select a group of the parameters as monitoring parameters, and these monitoring parameters are dynamically changed. In one embodiment, the monitoring parameters form sets of monitoring parameters, and each set of monitoring parameters is used to monitor the system for an associated period of time. The lengths of these monitoring periods are changed based on the rate of change of the correlation graphs. In an embodiment, the rate at which the monitoring parameters are changed is itself changed based on the rate of change of the correlation graphs.

A tunable light source having a temporal coherence length such that interference fringes are detected within the optical path difference of the interferometer is spectrally controlled to produce multiple wavelengths during sequential fractions of the integration time of the detector of the interferometer. The wavelengths are selected so as to produce a visible correlogram at each integration time according to spectrally controlled interferometry (SCI) principles. Such different wavelengths may be produced by stepwise or continuous modulation. The modulation step is repeated sequentially while changing the period of modulation to produce a succession of predetermined spatial patterns of interference fringes, as required for interferometric measurements. The approach enables the practice of SCI with common-path apparatus used for conventional phase shifting, thereby combining the advantages of high-coherence and white-light interferometry.

Method of determining a property of a sample from a correlogram obtainable by scanning of a surface of the sample through a focal plane of an objective using broad-band interferometry is provided. The correlogram may be displaying interference radiation intensity as a function of the scanning distance from the surface. The correlogram may be correlated with a secondary correlogram to obtain a cross correlogram or with the same correlogram to obtain an autocorrelogram. A property of the sample may be determined from the auto or cross correlogram.

The invention relates to a method for simultaneously analyzing at least two samples using a chromatography device comprising a chromatography column having an inlet and an outlet, and at least one detector placed at the outlet of the chromatography column, the method comprising steps of: injecting fractions of each independent sample at the inlet of the chromatography column, the fractions of each independent sample being injected according to a specific injection timing sequence derived from a pseudo-random binary sequence associated with said independent sample; recording a signal generated by said detector for a period of time at least equal to a duration of the longest of the specific injection timing sequences; cross-correlating the recorded signal and a derived correlation function, said derived correlation function being derived from the pseudo-random binary sequence associated with one of the independent samples, so as to obtain an individual correlogram signal specific to said independent sample; and analyzing data of interest of the individual correlogram signal so as to obtain an output signal indicative of a composition of the sample.

The invention relates to a method and an apparatus for measuring the thickness of a transparent film by broad band interferometry, comprising the steps of preparing a correlogram of the film by an interferometer, applying a Fourier transformation to said correlogram to obtain a Fourier phase function, removing a linear component thereof, applying a second integral transformation to the remaining non-linear component to obtain an integral amplitude function of said non-linear component, identifying the peak location of said integral amplitude function and determining the thickness of the film as the double value of the abscissa at said peak location considering a refractive index of a film which is dependent on wavelength. The last two steps may be replaced by identifying the peak locations of said integral amplitude function and determining the thickness of the films as the double values of the abscissas at the peak locations.