41 results about "Quadratic formula" patented technology

An arithmetic process of a quadratic formula that is contained in an exponent of a CAZAC sequence-defining expression is converted to an arithmetic process of a recursion formula to find the above-described exponent, the above-described exponent that was found is used to generate a CAZAC sequence, and the above-described CAZAC sequence that was generated is taken as the reference signal for transmitting and receiving or as a random access preamble signal.

The invention discloses a 6R robot inverse kinematic geometry solving method based on a screw theory and belongs to the field of robot kinematic inverse solution research. A basal coordinate system and a tool coordinate system are established, kinematic parameters of a 6R robot are determined through the basal coordinate system and the tool coordinate system, and a forward kinematic model is established; inverse solution motion of first three joints of the 6R robot is descripted in a decomposed mode, and a six-variable quadratic equation set is established; and a target position qe1 corresponding to an initial position qs1 is solved based on a screw forward kinematic model. Through the method, geometric description is combined with the screw theory, the geometrical significance is more explicit, the algebraic equation set is solved through a simplified inverse kinematic algorithm, the calculation efficiency is effectively improved, and a new inverse kinematics processing method is provided for real-time control over robot movement.

The invention discloses a method for estimating system harmonic impedance based on a three-point screening method. First, a regression equation between harmonic data and system harmonic impedance is established according to the harmonic analysis equivalent circuit, and then the relationship between the measured and estimated quantities is used to The phase angle relationship of the three-point data is established and reduced to the form of a quadratic equation, and the voltage and current data at the common coupling point when the background harmonic voltage is stable are screened out through the root-finding discriminant formula, and finally the partial The least square method is used to solve the regression equation and estimate the harmonic impedance of the system side. The results of simulation examples show that the present invention can reduce the influence of background harmonic voltage fluctuations on system harmonic impedance estimation, and has higher estimation accuracy and better stability than traditional methods.

The invention discloses a method and system for estimating the historical state of distribution network based on mixed measurement. The method of the invention improves the problem of lack of SCADA measurement data in the actual distribution network by establishing a SCADA and marketing mixed measurement state estimation model. , can more accurately calculate the load and power flow distribution of the distribution network, provide more accurate and reliable basic data for theoretical line loss calculation and distribution network economic analysis, and improve the accuracy of historical state estimation. The present invention decouples the state estimation modeling from the algorithm by constructing a distribution network hybrid measurement state estimation model in the form of a quadratic equation in a Cartesian coordinate system, and can use the existing mature state estimation algorithm to solve the problem and improve the distribution network hybrid measurement state estimation model. Measure state estimation efficiency and reliability.

The invention belongs to the technical field of video SAR moving target tracking and positioning, and in particular relates to a video SAR shadow-based positioning method. The method of the present invention: first, based on the collection of the absolute coordinates of the reference point in the video SAR imaging area, and the detection of the imaging results of the reference point, the relative coordinates, the absolute coordinates and the relative coordinates of the target are obtained, and then the overdetermined equation is established. group, and simplify the equation system, combine the common unknown parameters into new variables, and turn it into an overdetermined linear equation system. Finally, the least squares method is used to complete the estimation of the target parameters. This algorithm cleverly utilizes the commonality of quadratic parameters in solving equations, replaces quadratic equations with linear equations, and uses the parameter estimation advantage of least squares to effectively reduce the error of moving target estimation.

The invention provides a single-image space resection numerical calculation method, which comprises the following steps of: selecting three control points which are not on the same straight line from an image film, and constructing a ternary quadratic equation set according to the principle that vertex angles among corresponding light rays of three photographing light rays in an image space and an object space are equal; solving the undetermined values of the six exterior orientation elements in two steps, so that the position and attitude information of the shooting center of the shot image at the shooting moment can be determined. According to the method, the exterior orientation elements of the picture can be accurately estimated without providing any initial value, and the method is suitable for vertical photography, large-dip-angle photography and the like, and has the advantages of relatively simple and convenient calculation process, high calculation speed, accurate calculation result, stability, reliability and the like.

The invention discloses a multivariate quadratic equation mask encryption method. The method comprises: randomly generating n masks, wherein n is greater than or equal to 1; performing XOR encryption on the n masks and n keys in a one-to-one correspondence manner; calculating encrypted values of n monomials in an obtained multivariate quadratic equation by use of a masking algorithm according to the encrypted n keys, the n masks and a plaintext; and successively accumulating the encrypted values of the n monomials into a register to obtain a ciphertext. Through adoption of the method, the key security can be effectively improved, and a side channel attack can be defended.

A method for estimating a real estate price index based on a repeat sales model. The method includes the steps of eliminating corrupt portions of data used to determine price indices; regressing a difference in a log price of a second sale minus a log price of a first sale for a property on a set of dummy variables, eliminating the observations with zero residuals for estimating the dispersion function; using a quadratic formula to model a dispersion of residual values with respect to time interval; using the quadratic formula to solve for a dispersion for each time interval starting with a minimum positive value; determining a minimum dispersion value that is a value calculated from the quadratic formula; determining a maximum dispersion value that is calculated from the quadratic formula for each time interval starting with a minimum positive value, wherein the dispersion values are prevented from decreasing with increasing time intervals; repeating the step of regressing using the inverse of the square root of fitted values from the quadratic formula as weights; identifying and selecting the time periods and associated data for estimating a price index that covers a particular time period; excluding the index values which are determined to be unreliable; and obtaining an index series for a lower geographic level by using the index series of a higher geographic level.

The invention provides a linear equalization algorithm selection method and device and relates to the technical field of mobile communication. The method comprises the steps of calculating a noise inference covariance matrix Ruu on pilot subcarriers according to received multiway pilot signals and channel estimation; calculating an interference over thermal IoT according to the noise inference covariance matrix Ruu; comparing the interference over thermal IoT with a preset threshold; and determining to employ an interference rejection combining algorithm or a maximal ratio combining MRC algorithm according to a comparison result. According to the selection method and device provided by the invention, through utilization of the existing noise inference covariance matrix Ruu in the IRC, therelatively precise noise variance and interference receiving power are obtained based on a method of solving a quadratic equation, the interference over thermal IoT is calculated according to the noise variance and the interference receiving power, and the detection performance not lower than that obtained through independent adoption of the IRC or MRC is obtained.