38results about How to "Reduce matrix dimension" patented technology

The invention discloses a distribution network fault location method with a high fault-tolerant rate belonging to the technical field of AC distribution network fault diagnosis. The method achieves the fault location by comparing an overcurrent information matrix uploaded during a FTU fault with an overcurrent information matrix formed according to a network topology, and specifically includes: mapping a distribution network into a directed graph; according to the directed graph of the distribution network, obtaining an ideal fault matrix D; obtaining an reported information matrix G accordingto the information actually uploaded by the FTU; making subtraction on the ideal fault matrix D and the reported information matrix G to obtain a fault discriminant matrix P, thereby obtaining a fault region; and in view of missed reporting and false reporting, establishing a fault location criterion, and simulating a fault condition that the FTU generates missed reporting and false reporting according to the fault location criterion and a corresponding conditional probability. The method is simple in reasoning and good in fault tolerance. Particularly for the missed reporting and false reporting of the FTU, the provided fault location discrimination method and the expanded fault location region can improve the positioning accuracy.

The invention discloses an IRS-based large-scale MIMO cascaded channel estimation scheme under a hybrid low-precision architecture, which comprises the following steps: firstly, a base station end performing uniform division and phase configuration of units on a large-scale reflective array plane by sending a downlink configuration information signaling, and selecting a central unit of each sub-array plane to perform channel estimation; secondly, designing an isotropic analog receiver which adopts a full-connection phase shifter network, and enabling phases of all phase shifters to be uniformly distributed; then, the base station obtaining sparse information of an angle domain millimeter wave channel by utilizing a compressed sensing technology, so that a digital estimator is optimally designed, and angle domain channel estimation is obtained; and finally, through sparse recovery and angle domain inverse transformation, obtaining the cascade channel estimation of the sub-array surface,and further deducing to obtain the cascade channel estimation of all the IRS array surfaces. According to the method, the performance of channel estimation can be remarkably improved, and the amplification effect of the IRS on quantization noise is effectively inhibited.

The invention discloses a foundation radar and aerial mobile platform radar real-time error registering method. The real-time error registering method includes the steps of reporting the measurement of radars on objects, local geographical coordinates of the radars and the measurement on an attitude angle of a platform to a fusion center, obtaining an equivalent measurement equation, then carrying out sequential least square initialization and using a sequential least square method to estimate system errors of each radar and the attitude angle deviation of the platform, and finally using the estimated system errors and the estimated attitude angle deviation of the platform to compensate the system errors of the radars and the attitude angle deviation of the platform so as to achieve error registering on radar networking. Through reasonable modeling, the foundation radar and aerial mobile platform radar real-time error registering method obtains the absolute system error estimation on each radar, and the foundation radar and aerial mobile platform radar real-time error registering method is applicable to the situation that the distance between the radars is long.

A blind frequency-deviation estimating method of OFDM communication system carrier wave includes distributing virtual sub-carrier wave by emitter end in equal interval way, structuring low dimensional self-covariance matrix at receiver end through under-sampling way and utilizing subspace means to decompose obtained covariance matrix for obtaining estimation on carrier wave frequency deviation.

The invention provides a method of enhancing the down-link performance of TD-LTE, which relates to a wireless communication system. The method comprises the following steps that the number of antennaeThe invention provides a method of enhancing the down-link performance of TD-LTE, which relates to a wireless communication system. The method comprises the following steps that the number of antennae to be selected is confirmed on the basis of a maximized capacity criterion; the antenna subset selection and the minimum singular value calculation are carried out; the precoding matrix and the signato be selected is confirmed on the basis of a maximized capacity criterion; the antenna subset selection and the minimum singular value calculation are carried out; the precoding matrix and the signal-to-noise ratio are solved on the basis of a ZF criterion; transmission antennae are selected on the basis of a minimum error rate criterion; and finally, a base station finishes the sending of downwl-to-noise ratio are solved on the basis of a ZF criterion; transmission antennae are selected on the basis of a minimum error rate criterion; and finally, a base station finishes the sending of downward information. When the relativity of an antenna unit at the sending terminal exists, the number of the antennae is confirmed on the basis of the maximized capacity criterion, the transmission antenard information. When the relativity of an antenna unit at the sending terminal exists, the number of the antennae is confirmed on the basis of the maximized capacity criterion, the transmission antennae are selected on the basis of the minimum error rate criterion, and the adverse effect to MIMO and the precoding from the antenna relativity can be eliminated or weakened, thereby the capacity of tnae are selected on the basis of the minimum error rate criterion, and the adverse effect to MIMO and the precoding from the antenna relativity can be eliminated or weakened, thereby the capacity of the down-link of the TD-LTE system is increased, and the error ratio of the TD-LTE system is reduced; in addition, the number of radio frequency parts at the sending terminal of the TD-LTE system can bhe down-link of the TD-LTE system is increased, and the error ratio of the TD-LTE system is reduced; in addition, the number of radio frequency parts at the sending terminal of the TD-LTE system can be reduced, the dimensionality of the matrix which is involved in calculation during the treatment of MIMO can be ensured to be less, and the realization complexity and the cost are also reduced.e reduced, the dimensionality of the matrix which is involved in calculation during the treatment of MIMO can be ensured to be less, and the realization complexity and the cost are also reduced.

The invention provides a power grid state estimation method and device. A power grid comprises a first node, a second node and a third node, a PWU device is installed in the first node, and the method comprises the following steps: obtaining PMU measurement data of the first node in the power grid; calculating pseudo PMU measurement data of the second node satisfying a preset condition according to the PMU measurement data; obtaining SCADA measurement data of the third node in the power grid excluding the first node and the second node; and estimating a tidal current state of the power grid at present according to the PMU measurement data, the pseudo PMU measurement data and the SCADA measurement data. The technical scheme makes full use of the PMU measurement data and the SCADA measurement data, reduces the matrix dimensions in a power grid state estimation process, the modeling complexity and the solution difficulty through power grid decomposition and coordination calculation, and improves the power grid state estimation efficiency.

The invention discloses a fractional order system identification method based on Legendre wavelet multi-resolution analysis. The method comprises the following steps that firstly, Legendre wavelet orders are selected in the interval of [0,1]; secondly, an operation matrix of Legendre wavelet integration is derived by utilizing a block pulse function integral matrix; the input signal and the outputsignal of the system are expanded in the form of Legendre wavelet; the wavelet multi-fraction analysis characteristic is utilized, output signals are continuously decomposed, high-frequency information is discarded, the data length is reduced, and finally, system parameters and orders are solved in a cyclic fractional order integral mode by adopting a least square method and taking an IAE index as a target function. According to the method, the problems that parameter estimation is slow and a noise pollution system cannot be identified due to single dimension, high order and multiple coefficients of a traditional Legendre wavelet integral operation matrix identification method are effectively solved, the system identification speed is increased, and the influence of noise on the identification precision is reduced.

The invention discloses a three-dimensional alternate iteration unconditional stability FDTD algorithm in the technical field of FDTD algorithms. The method aims to solve the technical problems that an FDTD algorithm in the prior art is not suitable for calculation with fine grids due to limitation of CFL stability conditions, and calculation efficiency is affected due to the fact that a large number of memory resources need to be occupied. According to the algorithm, an ADI algorithm is combined with an idea of utilizing Laguerre-based expansion; writing the Maxwell equation set of the Laguerre domain into a matrix form; through a method of actively adding error terms, calculation of electric and magnetic field components is decoupled, unknown field quantities in the constructed linear equation set are all located on the same straight line, the dimensionality of the linear equation set is geometrically reduced in series, the calculation efficiency is greatly improved, and memory consumption is reduced. And finally, the size of an error term is enabled to tend to zero through an alternating direction iteration method to obtain an accurate solution of the electromagnetic field component.

The invention discloses a named entity recognition method and system based on a flat grid enhanced linear converter, and belongs to the field of natural language processing named entity recognition. Firstly, the text sequence sample is obtained and the label category of the entity is marked, and the text sequence is converted into a grid structure; then the recognition model is trained by minimizing the negative log likelihood loss function to the named entity recognition model; in the process of named entity recognition, For the text sequence to be recognized, it is used as the input of the trained named entity recognition model after text preprocessing, and the recognition result is obtained according to the maximum prediction score. The invention introduces lexical information based on a more efficient flat grid structure for lexical enhancement, provides prior knowledge and entity lexical boundary information for the model, and improves the recognition accuracy of the model for entity boundaries and entity types. The context information is modeled by using a linear converter, which reduces the complexity of the model, significantly improves the efficiency of the model operation, and has higher practical value.

The invention discloses a power consumption analysis method based on mean ridge regression. The method comprises the following steps: collecting power consumption data in the operation process of password equipment; calculating an intermediate value according to an algorithm structure; establishing a dynamic model for each hypothesis key based on association of a ridge regression thought and actually measured power consumption data, and performing equalization processing on a modeling result of each hypothesis key to establish a power consumption model; and calculating the correlation between the output value of the power consumption model and the actually measured power consumption data by adopting a Pearson's correlation coefficient, thereby realizing the analysis of internal secret information of the cryptographic algorithm and recovering the secret key information of the cryptographic equipment. According to the analysis method, the matrix dimension output by the power consumption model is effectively reduced through mean value modeling, and the calculation complexity of subsequent correlation analysis is effectively reduced. The analysis method has universality and is suitable for most block cipher algorithms.

The invention relates to a pseudo signal source identification method based on space projection, and belongs to the technical field of array signal processing. According to the method, under the condition that related information sources exist and the number of the information sources is unknown, when pseudo information source spectrum peaks exist in spatial spectrums of MUSIC, subspace fitting and other algorithms, the pseudo information sources can be identified, and therefore the accurate information source spatial distribution state is obtained. According to the method, an identification space and a confidence value calculation model are constructed by utilizing the uniqueness of a space complete base to vector description in a space, and a pseudo source spectrum peak is effectively identified by calculating a confidence value of each steering vector in the identification space, so that the method can be used as a post-processing means of spatial spectrum algorithms such as MUSIC and subspace fitting; high-precision direction finding under the condition that the number of information sources is unknown is achieved, and the engineering applicability of the algorithm is further improved.