1035 results about "Non linear functions" patented technology

A drilling control system provides, in one aspect, advisory actions for optimal drilling. Such a system or model utilizes downhole dynamics data and surface drilling parameters, to produce drilling models used to provide to a human operator with recommended drilling parameters for optimized performance. In another aspect, the output of the drilling control system is directly linked with rig instrumentation systems so as to provide a closed-loop automated drilling control system that optimizes drilling while taking into account the downhole dynamic behavior and surface parameters. The drilling models can be either static or dynamic. In one embodiment, the simulation of the drilling process uses neural networks to estimate some nonlinear function using the examples of input-output relations produced by the drilling process.

A method and system for full-field fringe-projection for 3-D surface-geometry measurement, referred to as “triangular-pattern phase-shifting” is disclosed. A triangular grey-scale-level-coded fringe pattern is computer generated, projected along a first direction onto an object or scene surface and distorted according to the surface geometry. The 3-D coordinates of points on the surface are calculated by triangulation from distorted triangular fringe-pattern images acquired by a CCD camera along a second direction and a triangular-shape intensity-ratio distribution is obtained from calculation of the captured distorted triangular fringe-pattern images. Removal of the triangular shape of the intensity ratio over each pattern pitch generates a wrapped intensity-ratio distribution obtained by removing the discontinuity of the wrapped image with a modified unwrapping method. Intensity ratio-to-height conversion is used to reconstruct the 3-D surface coordinates of the object. Intensity-ratio error compensation involves estimating intensity-ratio error in a simulation of the measurement process with both real and ideal captured triangular-pattern images obtained from real and ideal gamma non-linearity functions. A look-up table relating the measure intensity-ratio to the corresponding intensity-ratio error is constructed and used for intensity-ratio error compensation. The inventive system is based on two-step phase-shifting but can be extended for multiple-step phase-shifting.

In a database, a frequently retrieved column is encrypted using a common key, and other columns are encrypted using a specific row key. Thus, a retrieving process can be performed at a high speed, and the security can be improved. Then, the row and column of the database are encrypted by assuming the plaintext to be encrypted as a bit string, and performing a binary operation with a random bit string. A random bit string is obtained by sequentially generating multidimensional vectors using a nonlinear function by defining a predetermined bit length as 1 word and a plurality of words as components of the multidimensional vector.

Systems, methods, and computer programs for high quality wide-range multi-layer image compression coding, including consistent ubiquitous use of floating point values in essentially all computations; an adjustable floating-point deadband; use of an optimal band-split filter; use of entire SNR layers at lower resolution levels; targeting of specific SNR layers to specific quality improvements; concentration of coding bits in regions of interest in targeted band-split and SNR layers; use of statically-assigned targets for high-pass and/or for SNR layers; improved SNR by using a lower quantization value for regions of an image showing a higher compression coding error; application of non-linear functions of color when computing difference values when creating an SNR layer; use of finer overall quantization at lower resolution levels with regional quantization scaling; removal of source image noise before motion-compensated compression or film steadying; use of one or more full-range low bands; use of alternate quantization control images for SNR bands and other high resolution enhancing bands; application of lossless variable-length coding using adaptive regions; use of a folder and file structure for layers of bits; and a method of inserting new intra frames by counting the number of bits needed for a motion compensated frame.

A media noise optimized (MNO) detector for a read channel compensates for pattern dependent media noise, and compensates for nonlinearities from many sources such as residual MR nonlinearity, residual nonlinear transition shift, partial erasure, write-induced nonlinearity, and steady-state mis-equalization. The MNO detector is implemented by adjusting a conventional Viterbi detector branch metric so that the channel output value (ideal value) can be a nonlinear function of the state/branch bits, and the branch metric scaling factor is a function of the state/branch. For a given state/branch, the ideal value is the mean of analog-to-digital converter samples for the pattern corresponding to the state/branch, and the branch metric scaling factor is proportional to the noise variance for the pattern corresponding to that state/branch.

Indicating a spatial location of a virtual sound source by determining an output for each of one or more physical speakers as a function of an orientation of corresponding virtual speakers that track the position and orientation of a virtual listener relative to the virtual sound source in a virtual environment or game simulation. A vector distance between the virtual sound source and each virtual speaker is used to determine a volume level for each corresponding physical speaker. Each virtual speaker is specified at a fixed location on a unit sphere centered on the virtual listener, and the virtual sound source is normalized to a virtual position on the unit sphere. All computations are performed in Cartesian coordinates. Preferably, each virtual speaker vector distance is used in a nonlinear function to compute a volume attenuation factor for the corresponding physical speaker output.

The invention discloses a vehicle front trafficability analyzing method based on a convolution nerve network. The method comprises the following steps: first, a vidicon arranged in the front of a vehicle is used for collecting a large number of actual vehicle traveling environment images; a Gamma rectification function is used for pre-processing the images; training of the convolution nerve network is conducted. According to the method, a nonlinear function superimposed Gamma rectification method is used for pre-processing the images, so that influence of light illumination of strong changes on identification of objects is avoided, and the image resolution ratio is improved. According to the method, a geometry normalization method is used, so that the resolution ratio difference caused by identifying the distance of an object distance vidicon is reduced. The convolution nerve network LeNet-5 adopted in the method can extract implicit expression characteristics with class distinguishing capacity and is simple in extracting process. The LeNet-5 is combined with a local receptive field, weight share and secondary sampling to ensure robustness of simple geometry deformation, reduce training parameters of the network, and simplify the structure of the network.

A method for predicting future states of a vehicle including the steps of selecting a model having n states reflecting dynamic features of the vehicle; inputting noisy sensor measurements representing a current state of the vehicle to generate (2n+1) sigma points X_i where i=0, . . . . 2n, each of the sigma points having n states; performing (2n+1) integrations, each integration includes propagating the n-states of the respective sigma points X_i through the non-linear function Y_i=f(X_i); and combining the propagated sigma points to generate the predicted future states of the vehicle.

The invention discloses a structure and a design method of an improved active-disturbance-rejection position controller for a direct current (DC) motor; the DC motor is taken as a controlled object, and an output position signal is taken as a controlled variable; the controller mainly consists of four parts, i.e., a tracking differentiator, a nonlinear state error feedback part, an extended state observer and a disturbance compensation part. The improved active-disturbance-rejection position controller is mainly used to improve a fal function in a nonlinear function in the extended state observer, and the fal function is used to determine the tracking performance of the extended state observer and the controller; the concrete improvement measure is adding a linear feedback area into non-linear feedback; therefore, the problem that in the traditional method, timely control cannot be realized when the system error is too large and the gain is too low can be solved on the basis of guaranteeing system stability. By comparing simulation lines obtained before and after the improvement for the controller, the structure and the design method which are provided by the invention are proved to accelerate the output signal response speed under the condition that the position error of the DC motor is larger, thus improving the integral control performance of a system.

An RF amplifier system employing an analog predistortion module is disclosed. The disclosed analog predistortion module is based on zero crossings of the gain error curves (AM-AM and AM-PM curves minus DC). The hardware structure uses the product of first-order functions avoiding the need for large differential swings in the coefficients to shape the lower part of the gain curves. The higher-order nonlinear functions are preferably derived from a single envelope detector. An equal number of multipliers are preferably used in each path when the order of the magnitude and phase corrections are equal or differ by one, thus reducing delay mismatches between the magnitude and phase correction signals.

An apparatus for providing low frequency expansion of speech includes a nonlinear function element, a band-pass filter element and a level control element. The non-linear function element is configured to receive a signal including at least two harmonic components and to produce a signal including at least one lower frequency harmonic component having a lower frequency than a highest frequency component of the at least two harmonic components responsive to the signal including at least two harmonic components. The band-pass filter element is in communication with the non-linear function element and configured to filter the signal including the at least one lower frequency harmonic component. The level control element is configured to apply a level control to alter the filtered signal based on a feature vector associated with an input speech signal.

A method of estimating diaphragm excursion of an electrodynamic loudspeaker may be performed using audio signals. An audio output signal may be applied to a voice coil of the electrodynamic loudspeaker through an output amplifier to produce sound. A detected voice coil current and a determined voice coil voltage may be applied to a linear adaptive digital loudspeaker model that has a plurality of adaptive loudspeaker parameters. The parameter values of the adaptive loudspeaker parameters may be computed based on the linear adaptive digital loudspeaker model and applied to a non-linear state-space model of the electrodynamic loudspeaker. For the non-linear state-space model, a predetermined non-linear function may be applied to at least one of the plurality of received parameter values to compute at least one non-linearity compensated parameter value of the adaptive loudspeaker parameters, to determine an instantaneous excursion of the diaphragm.

A micro satellite MEMS gyroscope error compensation method based on an integrated nerve network comprises: (1) founding an integrated nerve network model, (2) acquiring a studying sample, (3) training the integrated nerve network, (4) compensating the error of the micro satellite MEMS gyroscope. The integrated nerve network fits a trained sample excessively through integrating a plurality of nerve network weak learning devices and overcomes the defects of low precision of predication manifested by a single nerve network and low stability, effectively improves the stability of the system and the precision of the predication, and enforces the generalization ability of the system. The nerve network after being trained can get infinitely close to the nonlinear functions of input or output signals of the gyroscope with high precision and can realize the compensation of high precision of the micro satellite MEMS gyroscope with low calculation cost.

The invention relates to a spacecraft fault tolerance attitude cooperation tracking control method based on a normalized neural network, and belongs to the technical field of spacecraft formation flight. According to the method, an attitude motion model of a single spacecraft is built, errors are defined, a control law is designed for the model, a sliding mode function is designed, the derivative of the sliding mode function is solved, an error model is obtained, a control law based on an input normalized neural network is designed, and the states of the spacecrafts are cooperative and consistent; each spacecraft calculates the required control torque according to attitude information of itself and the adjacent spacecraft, the calculated control torque is acted on the corresponding spacecraft via an execution mechanism of each spacecraft, the angular velocity is solved via an obtained attitude dynamic equation, a unit quaternion attitude tracks an expected attitude via the attitude dynamic equation, and consistent attitude of the spacecraft formation is finally realized. According to the method, estimation errors of non-linear function approximation are reduced, the calculating time is reduced, and the convergence rate and the control precision of the system are increased.

A method is described for predistorting an input signal to compensate for non-linearities caused to the input signal in producing an output signal. The method comprises: providing an input for receiving a first input signal as a plurality of signal samples, x[n], to be transmitted over a non-linear element; providing at least one digital predistortion block comprising, a plurality of IQ predistorter cells coupled to the input, each comprising a lookup table (LUT) for generating an LUT output The at least one digital predistortion block block is configured to apply interpolation between LUT entries for the, plurality of LUTs; and generate an output signal, y[n], by each of the plurality of IQ predistorter cells by adaptively modifying the first input signal using interpolated LUT entries to compensate for distortion effects in the non-linear element. A combiner may be provided configured to combine the output signal samples, y_Q, from the plurality of IQ predistorter cells into a combined signal to generate the output signal, y[n], for transmission to the non-linear element. An error calculation block may be coupled to a digital predistortion adaptation block to determine and modify a predistortion performance.

The invention relates to a reservoir shear wave velocity prediction method based on rock physics. The method comprises the steps that (1) supposing that the bulk modulus, the shear modulus and the density of a destination interval mineral are unknown constants, the error between a longitudinal wave velocity and a measured longitudinal wave velocity is acquired according to equation modeling, and the error between the acquired density and the measured density is calculated; (2) according to the minimum error criterion, the bulk modulus, the shear modulus and the density of a mineral component are inverted through a genetic algorithm; (3) and the shear wave velocity is calculated. According to the step (1), supposing that the elastic modulus of each rock component is an unknown constant in a reservoir logging curve section, the objective function of the inversion of the logging curve can be defined that a superscript M represents a simulation longitudinal wave velocity, O represents a logging observation longitudinal wave velocity, and w Rho and w rho represent normalized weighted coefficients; and the objective function is a nonlinear function of the bulk modulus, the shear modulus and the density of each mineral component. The method can be applied to a sand shale reservoir, and carbonate rock and other complex reservoirs.