816 results about "Linear transform" patented technology

The invention relates to an encryption method for network and information security; the adopted packet length and key length are 128 bits, and a 128-bit system parameter is added; encryption algorithm comprises a plurality of rounds of round transform iteration consisting of mixed layers and diffusion layers, wherein the last round is incomplete round transformation, and the incomplete round transformation consists of the mixed layer; the mixed layer comprises key plus, S box portfolio transform and system parameter minus; the S box portfolio transform comprises 8-input 8-output reversible S box transform and inverse S box transform in the same number which are output by parity exchange; the diffusion layer can construct linear transformation with a reversible re-model polynomial matrix; an encryption round key is generated by an encryption key through encryption round transformation; and decryption algorithm is the inverse transformation of encryption algorithm. The encryption methodfor network and information security has the advantages of high diffusion speed, good security strength, hardware resource saving, and very high speed when being realized by hardware and on a software platform.

A privacy-preserving scalar product calculation system is provided. A first unit linearly transforms an n-dimensional vector Va into an n-dimensional vector based on a scalar value based on a random number W_i and a random number R_j to calculate a remainder by dividing each element of the linearly transformed n-dimensional vector by a random number M_i, and transmits an n-dimensional converted vector X including each of the remainders as its element to the second unit, the second unit calculates an inner product value Z based on the received n-dimensional converted vector X and an n-dimensional vector Vb, and transmits the inner product value Z to the first unit, and the first unit further calculates, based on a reciprocal of the scalar value and the receive inner product value, a scalar value and which calculates a remainder by dividing the scalar value by the random number M_i.

A system and method is described for rendering a warped brush stroke using a bitmap brush image, the brush stroke being along a arbitrarily curved guideline. The described system and method generate a piecewise linear approximation to the guideline followed by generating polygons with the aid of the linear segments such that the generated polygons are convex and contiguous linear segments result in contiguous polygons. A mapping is identified between segments of the bitmap brush and the polygons such that the corners or the boundaries of the segments of a segment map to the corners or boundaries of a corresponding polygon. The segment of the bitmap brush is mapped into the corresponding polygon using transformations that do not require visiting a pixel in the rendered warped brush stroke more than once. Examples of such transformations include bilinear transformations and texture mapping in combination with tiling.

A linear transform such as a Fast Fourier Transform (FFT) is performed on an input data set having a number of points using one or more arrays of concurrent threads that are capable of sharing data with each other. Each thread of one thread array reads two or more of the points, performs an appropriate “butterfly” calculation to generate two or more new points, then stores the new points in a memory location that is accessible to other threads of the array. Each thread determines which points it is to read based at least in part on a unique thread identifier assigned thereto. Multiple transform stages can be handled by a single thread array, or different levels can be handled by different thread arrays.

The invention discloses an extraction method for brain-computer interface system imagination action EEG signal features, in particular to an EEG feature extraction method based on a wavelet transform and a BP neural network. The invention takes the energy change caused by imagination action thinking to be a feature distinguishing the imagination movements of a left hand and a right hand, respectively calculates the point-to-point average power of the entire samplings of the EEG signal obtained from C3 and C4 channels by the left hand and the right hand through the imagination (thereinafter called as C3 and C4 of the left hand and the right hand) within 0 to 9s according to the average power formula. A time window is arranged, a discrete dyadic wavelet transform is made to the data of a section provided with the window, an approximation signal a6 on a sixth size is selected to be taken as a signal feature; a BP neural network is used as a classifier to classify. The method of the invention adopting the wavelet transform and the BP neural network to extract the potential of the imagination movement helps to improve the signal/noise ratio and the identification correction rate of the potential of the imagination action; in addition, the wavelet transform is a linear transform, has a quick calculation speed, and is suitable for on-line analysis.