84 results about "Characteristic polynomial" patented technology

Techniques to improve the acquisition process in a spread spectrum environment. The signals from different CDMA systems are spread with different sets of PN sequences, with the PN sequences in each set being uncorrelated to the PN sequences in the other sets. By using uncorrelated PN sequences, the likelihood of detecting a pilot signal from an undesired system is reduced or minimized, and the mean time to acquisition of the pilot signal from the desired system is improved. The mobile station can attempt to acquire the pilot signal by processing the received signal with a first set of PN sequences corresponding to a first hypothesis of the particular signal being acquired. If acquisition of the pilot signal fails, a second set of PN sequences corresponding to a second hypothesis is selected and used to process the received signal. The PN sequences in the second set are uncorrelated to the PN sequences in the first set. The PN sequences for the first set can be generated based on the characteristic polynomials defined by IS-95-A, and the PN sequences for the second set can be the reverse of the PN sequences for the first set.

At a time of enrollment, a client terminal: generates a feature polynomial from biometric information for enrollment; multiplies the feature polynomial by a prescribed integer; stores a helper polynomial obtained by multiplying an inverse polynomial of a template polynomial, a polynomial having a small norm; and transmits the template polynomial to an authentication server. The authentication server stores the template polynomial in a storage unit. At a time of authentication, the client terminal: generates a feature polynomial from biometric information for authentication; multiplies the helper polynomial by the feature polynomial; adds a random polynomial having a small norm to the authentication polynomial; and transmits the authentication polynomial to the authentication server. The authentication server determines whether or not the biometric information for enrollment and for authentication can be authenticated, based on the result obtained by multiplying the authentication polynomial by the template polynomial.

The invention relates to a characteristic point three-dimensional reconstruction method based on trifocal tensor, which includes the following steps: coding points, marking points and a ruler are arranged on the surface of the measured object; a digital camera is used to take photos of the measured object in multiple angles, and the photos are inputted to a computer for image processing to obtain the image coordinates (xd, x'd and x''d); all images are rearranged for normalization treatment according to the image coordinates (xd, x'd and x''d); the trifocal tensor of each group of images is respectively calculated to determine the three-dimensional point coordinates of the coding points and the marking points; each group of three-dimensional point coordinates is processed to obtain the three-dimensional coordinates (x, y and z) of each point in the unified coordinate system; the specific value of the length and the actual length is calculated through the ruler to obtain new three-dimensional point coordinates (x', y' and z') in metric space; the new three-dimensional point coordinates (x', y' and z') receive focusing control to obtain integrally optimized three-dimensional point coordinates. The three-dimensional reconstruction method in the invention has high calculation accuracy, simple use, convenient operation, needs only a portable digital camera, a common laptop, a group of coding points and marking points, and a ruler.

The invention provides a data label mining method, which comprises the following steps that: the number of occurrence times of open data labels obtained from Internet in advance and basic data labels in a pre-built basic data label system are counted; in addition, the number of co-occurrence times of the open data labels and the basic data labels are counted; the confidence degree is obtained by utilizing the counted number of occurrence times and the counted number of co-occurrence times; and when the number of co-occurrence times is greater than a preset first threshold or the confidence degree is greater than a preset second threshold, or the confidence degree is greater than a sum value of the average confidence degree and the confidence degree standard deviation, the open data labels are used as characteristic labels of the basic data labels to be added to a basic data label system. The invention also provides a data label mining system. According to the technical scheme provided by the invention, the hierarchical mining of the data labels can be realized, and the hyponymy accuracy of the mined data labels can be improved.

The invention relates to a method for analyzing the impact on the ultralow frequency oscillation of a power system from uncertain parameters, and belongs to the technical field of grid safety. The method comprises the steps: building a unified frequency model which comprises a main generator set speed regulator of a system and a prime motor model; obtaining set parameters of the unified frequency model according to the operation state of the system, and selecting the uncertain parameters to be researched; calculating a transfer function and a characteristic polynomial, comprising the uncertain parameters, of the unified frequency model; calculating the expression of the characteristic polynomial at the ultralow frequency, and analyzing the impact on the stability of the system through the zero exclusion principle; drawing the value set of the characteristic polynomial through a value set method, and verifying and analyzing the impact on the stability of the system from the uncertain parameters. The method achieves the mechanism analysis of the impact on the ultralow frequency oscillation from the parameters of the system, is simple, is effective, and can reflect the cause of the ultralow frequency oscillation so as to take corresponding measures to inhibit the ultralow frequency oscillation.

A term-by-document (or part-by-collection) matrix can be used to index documents (or collections) for information retrieval applications. Reducing the rank of the indexing matrix can further reduce the complexity of information retrieval. A method for index matrix rank reduction can involve computing a singular value decomposition and then retaining singular values based on the singular values corresponding to singular values of multiple topics. The expected singular values corresponding to a topic can be determined using the roots of a specially formed characteristic polynomial. The coefficients of the special characteristic polynomial can be based on computing the determinants of a Gram matrix of term (or part) probabilities, a method of recursion, or a method of recursion further weighted by the probability of document (or collection) lengths.

The application discloses a dynamic signal parameter acquisition method, comprising the steps of selecting dynamic sampling signal sequences of a power grid to form an autocorrelation matrix; determining an effective rank of the autocorrelation matrix and frequency components of the dynamic sampling signal sequence; establishing an auto-regressive (AR) model, and resolving a model parameter of the AR model; through a Prony algorithm, determining a dynamic sampling signal expression and a complex sequence, wherein the dynamic sampling signal sequence is expressed by the complex sequence under a condition of satisfying square error minimization; and introducing a characteristic polynomial root corresponding to the model parameter into the complex sequence, and resolving various parameters of the dynamic sampling signal sequence. The application, instead of directly solving parameters in the Prony algorithm, regards a current moment signal as a linear combination of original various moment signals through an AR parameter model thought, and converts a nonlinear problem into a linear estimation problem, so that the computing process is simpler and computing result is more accurate.

The invention relates to a quick low-level image matching method by utilizing flight control data, comprising the steps of: marking loading equipment to determine a coupling relation of an aerial photography camera and an aircraft; building a corresponding relation of low-level images and flight control data through the camera shutter triggering time provided by the flight control data; determining a ground coverage range of the low-level images through the flight control data (longitude and latitude, height and postures), and building an image topological relation; detecting image characteristic points through a characteristic point extraction algorithm, generating a characteristic point descriptor and building an initial characteristic point dictionary; and filtering repeated characteristic points or pseudo characteristic points through the image topological relation and the characteristic point dictionary, and amending the characteristic point dictionary to generate a final image matching relation. The matching method disclosed by the invention improves image matching efficiency and reliability and provides support for the conventional reconstruction of large-scene quick images.

The invention relates to the transmission data checking field, in particular to a technology for generating a low-cost CRC check code by a hardware circuit. A device for generating a cyclic redundancy check code and a method thereof have a characteristic polynomial, namely g(x) is equal to sigma plus 1; the device comprises trigger groups which are respectively corresponding to x<n1>-x<nk> and formed by a plurality of serially connected triggers; the trigger groups are serially connected in the sequence of the serial numbers of the trigger groups; an exclusive-or gate is connected between two neighboring trigger groups in series; an output terminal of an inverter is connected with an input terminal of a DG1 trigger group; an input terminal of an exclusive nor gate is the input terminal of the device, and the other input terminal of the exclusive nor gate is connected with the output terminal of a DGk trigger group; the output terminal of the exclusive nor gate is connected with the input terminal of the inverter and the input terminals of each exclusive-or gate. In a circuit of the prior art, the inverter connected with each trigger is removed and the inverter is connected to invert before the data is input to the triggers connected in series, thus the method saves a great number of inverters, simplifies a CRC check code generation circuit, and lower the hardware cost.

The invention discloses a method for damping control of an LCL grid-connected inverter based on dimension reduction observation. The method includes the steps that a single-phase system differential equation of a grid-connected LCL filter is established; the system equation is decomposed into a subsystem without reconstruction and a subsystem needing reconstruction; a characteristic polynomial for the reconstruction subsystem is solved; a dimension reduction observer for the reconstruction subsystem is designed; a characteristic equation of the dimension reduction observer is solved. According to the method for damping control, a sensor for sampling capacitor voltages or capacitor currents in a traditional control method is omitted, the capacitor currents are observed through feed-forward, and then system resonance is restrained and system reliability is improved.

The invention discloses a fingerprint detail information hiding and recovering method based on set polynomial conversion and harmonics. According to the basic thinking, a triangular quantization expression with displacement and rotation invariance is built through the Delaunay triangulation algorithm on the basis of fingerprint detail characteristics, so that a characteristic polynomial is built on a quantization expression set, assessment elements of non-characteristic space are introduced by means of the harmonics thinking of the set, and information hiding and verification recovering of the fingerprint detail characteristics are achieved. The method overcomes the defect that a finger template of an intelligent card stores information with plaintext and is attacked easily, improves system safety, effectively protects privacy of the biological characteristics of fingers of a user, and can be widely applied to a plurality of application scenarios like passports, identification cards and entrance guard cards.

A calibration method of electrocardiogram signals and the application program for the same. The method comprises steps of receiving an uncalibrated/unidentified electrocardiogram signal of a user, calculating the ratio of the distance length of an uncalibrated/unidentified electrocardiogram signal and the distance length of an electrocardiogram template, then generating a trigonometric value which corresponds with a trigonometric projection degree according to the ratio. Next step is to set a characteristic point of the uncalibrated electrocardiogram signal as an axis anchor point of the trigonometric projection for attaining a displacement. Lastly, perform the calibration on the unidentified electrocardiogram signal according to the generated trigonometric value which corresponds with trigonometric projection degree and the attained displacement. Then perform identification comparison of the unidentified electrocardiogram signal and the saved electrocardiogram template for further authorization.

A final state in a shift register arrangement is obtained from an initial state by means of N-fold iteration using an iteration rule prescribed by a characteristic polynomial f(x) of n-th order. To determine the final state, a tap mask which is characteristic of N′ shift register operations is calculated. Using the tap mask, n shift register operations are performed. This produces the n bits of an N′-fold iterated state of the shift register arrangement. Any remaining N-N′ iterations which are needed are performed in another manner.

The invention provides an image compression method. The image compression method includes the following steps that a data matrix of an image to be compressed are generated, and the data matrix is centralized or standardized; a variance matrix of the centralized or standardized data matrix is calculated; a characteristic polynomial of the variance matrix is converted into a high-order characteristic polynomial, and the number of roots of the high-order characteristic polynomial is judged; according to the number of the roots and a preset initial solution, iteration solving is conducted on the high-order characteristic polynomial, when the number of the roots acquired through iteration solving is four, the four roots are calculated according to a mathematical expression, acquired through the current iteration solving, of the characteristic polynomial, all characteristic roots are output, and characteristic vectors are calculated according to the characteristic roots; a transformation matrix is acquired according to the characteristic vectors, and the compressed image is acquired by multiplying the transformation matrix by the data matrix. By the adoption of the image compression method, the operand in the image compression process is small, and the compression speed is high.

The invention provides a Prony analysis method suitable for low-frequency oscillation and subsynchronous oscillation identification, and the method comprises the steps: constructing a sample matrix ofan extended order based on actual measurement data; determining an effective rank of the sample matrix by adopting a method based on singular value decomposition, i.e., a calculation order of a Pronyalgorithm; solving a characteristic polynomial, and constructing a new matrix equation according to the solved characteristic root; adopting a BP neural network-based method to iteratively solve theconstructed matrix equation; and calculating Prony parameters: amplitude, attenuation factor, frequency and initial phase based on the solved characteristic root and the solution of the matrix equation. The invention provides a new method for order determination by using a Prony calculation method. The defects of a calculation order selection method in a traditional algorithm can be overcome; themethod is advantaged in that quasi-order determination is realized, iterative solution is carried out through employing a BP neural network-based method, defects of a conventional algorithm in complexmatrix calculation are improved, complex matrix equation solution speed of the Prony algorithm is improved, and the method is superior to a conventional Prony algorithm to a certain degree.

A method and apparatus for generating a code after a random time in a communication system using an n-stage Linear Feedback Shift Register (LFSR) are provided. The method includes expressing an element indicating the current state value of the LFSR in a finite field GF(2ⁿ), performing a 2^r-th power operation and a multiply operation with respect to the characteristic polynomial using the LFSR when n=rs in the GF(2ⁿ), and repeating the 2^r-th power operation and the multiply operation s times to calculate a new state value of the LFSR after the random time, thereby generating the code.