摘要:
A method and apparatus is taught for a signal processing breakthrough that significantly alleviates the “Curse of Dimensionality” (COD) in the characterization of nonlinear physical systems; namely, the reduction in the number of coefficients used to describe the higher order (i.e., nonlinear) kernels in the Volterra series expansion. The latter technique provides the means to evaluate simultaneously from a wide band excitation, all the inter-modulation products up to a specified order by greatly reducing the number of coefficients in the higher order kernel estimation to a manageable set that can be easily manipulated by current personal computers used to enhance a finite element (FE) model that generates a bio-inspired acoustic transducer model.
摘要:
A fault detection system designed to evaluate the structural integrity of a material employs an array of sensors disposed over the material being evaluated. The sensors detect vibrations in the material and the sensor signals are fed to a data processor. The processor employs a method to analyze the linear and nonlinear characteristics of the sensor signals and then determines whether to proceed with a linear signal processing analysis or a nonlinear signal processing analysis of the sensor signals. Once the analysis is completed, the results are compared to baseline results to determine what if any divergence exists between the results and the baseline results. A significant divergence indicates a potential material failure. The fault detection system will indicate such a potential failure through a visual alarm on a graphical user interface.
摘要:
A fault detection system designed to evaluate the structural integrity of a material employs an array of sensors disposed over the material being evaluated. The sensors detect vibrations in the material and the sensor signals are fed to a data processor. The processor employs a method to analyze the linear and nonlinear characteristics of the sensor signals and then determines whether to proceed with a linear signal processing analysis or a nonlinear signal processing analysis of the sensor signals. Once the analysis is completed, the results are compared to baseline results to determine what if any divergence exists between the results and the baseline results. A significant divergence indicates a potential material failure. The fault detection system will indicate such a potential failure through a visual alarm on a graphical user interface.
摘要:
The invention is a method for improved active sonar using a singular value decomposition filtering and a Volterra-Hermite Basis Expansion to model real active sonar measurements. The fitting model minimizes the sum of the squared errors between a measured channel response, z(t), and model response, y(t), which is a fitted Volterra Series solution. The model requires as input an excitation waveform, x(t), to which is fitted the model response, y(t). A contracted broadband cross-ambiguity function is used to correct the excitation waveform for Doppler and range effects. Once completed, the modeled response can be used to determine the linearity or non-linearity of the channel effects. Appropriate measures can be utilized to reduce these effects on the measured channel response.
摘要:
A method is provided for identifying a disease of a patient. The method includes collecting data of at least one cardio-respiratory function of the patient over time, eliminating artifacts from the collected data to create a new data record, constructing a phase-space from the new data record, and constructing a hypercube covering the phase-space. The method further includes calculating threshold criteria for quantifying dispersion characteristics of an attractor of the phase-space and determining the patient's tendency towards the disease based on the threshold criteria.
摘要:
The invention is a method for improved active sonar using a singular value decomposition filtering and a Volterra-Hermite Basis Expansion to model real active sonar measurements. The fitting model minimizes the sum of the squared errors between a measured channel response, z(t), and model response, y(t), which is a fitted Volterra Series solution. The model requires as input an excitation waveform, x(t), to which is fitted the model response, y(t). A contracted broadband cross-ambiguity function is used to correct the excitation waveform for Doppler and range effects. Once completed, the modeled response can be used to determine the linearity or non-linearity of the channel effects. Appropriate measures can be utilized to reduce these effects on the measured channel response.
摘要:
A sonar system and method are provided to extract and identify information about a particular target illuminated by an active sonar system. The present invention utilizes a Volterra Series Expansion in conjunction with a least squares procedure to estimate channel and target responses, which may be linear or nonlinear. The system estimates the channel and target responses for different orders of the Volterra Series Expansion and then selects the order for which a minimum error is determined with respect to a measured acoustic return signal. The system requires as inputs only the excitation waveform and the measured acoustic return signal.
摘要:
A method of detect the onset of turbulence in connection with a body movinghrough a fluid medium. First, the body is supplied with sensors each for generating a signal suitable for measuring amplitude of pressure fluctuations of the medium proximate a region of said sidewall of the body in at least a region of the body in which turbulence is expected to occur. During a reference stage during which the body moves through the fluid medium when it is known that turbulence is occurring around at least a portion of said body , the sensors each generate reference temporal pressure data representing fluctuations in pressure of the fluid medium around said body. In response to reference temporal pressure data generated by sensors in a turbulence zone at which turbulence is occurring and sensors in a transition zone between the turbulence zone and a laminar flow zone, a method-of-delay phase portrait is generated for each of a progression of selected delay intervals. These operations are repeated during an operational stage, and phase portraits generated during the operational stage are compared to phase portraits in response to the reference temporal pressure data from the transitional zone and the turbulence zone, for corresponding ones of said selected delay intervals,, and a determination of the onset of turbulence is made in response to such comparison.
摘要:
A high throughput RNAi-based assay for identify factors involved in maintaining epigenetic silencing is disclosed. The assay measures reactivation of a silent reporter gene in cells, resulting from RNAi-based knockdown in target mRNA. RNAi-based screening of these silent reporter cells has identified known enzymes that place or remove epigenetic marks on histones, as well as non-enzymatic proteins that function in silencing or in transfer of marks during S-phase. In addition, the screen has been used to identify a number of novel gene products involved in epigenetic silencing, which are also disclosed.
摘要:
A system is disclosed that applies non-linear signal processing methods derived from theories of information and non-linear oscillations (chaos) to control the turbulent boundary layer of marine vessels in order to reduce the drag to which the vessels encountered while moving in water. The system uses measurement probes mounted along the hull of a marine vessel to provide detection markers for increase or decrease in the drag based on a prescribed fluid (i.e., air) injection and flow rate in boundary layer. The invention utilizes a differential radius (DR) to determine the minimum entropy for a given flow rate in the boundary layer which defines the optimum condition used by the system for reducing drag.