167 results about "Frequency space" patented technology

The invention provides a partial discharge mode recognition method based on multi-channel sound signal time-frequency space spectrogram fusion, and belongs to the technical field of partial discharge mode recognition. The problem that information redundancy and difference between existing multi-channel sound signals cannot be effectively fused and discriminant features cannot be extracted is solved. The method comprises the following steps: collecting and summarizing multichannel sound signal data corresponding to different partial discharge models as a data set; performing normalization processing on the original multichannel partial discharge sound signal, and mapping a time domain signal into time-frequency joint distribution to obtain a gray scale time-frequency spectrogram; performing multi-scale and multi-direction decomposition on the grayscale time-frequency spectrogram to obtain each channel sub-graph; different fusion strategies are used for fusing the channel sub-graphs obtained through decomposition; reconstructing a time-frequency space fusion spectrogram from the fused sub-graphs of each channel through inverse transformation; extracting features; identifying a partial discharge mode; the method is applied to partial discharge detection.

The invention discloses an I SAR fusion imaging method, system and device based on centralized multi-station networking, and relates to the technical field of radar imaging, and the method comprises the steps: obtaining I SAR frequency domain echo data of each subsystem; performing frequency domain space matching on the frequency domain echo data based on the observation angle difference of each radar; performing frequency domain alignment processing on the matched frequency domain data; and fusion and imaging are carried out. According to the I SAR fusion imaging method, system and device based on the centralized multi-station networking, the imaging resolution is remarkably improved, multi-station frequency domain data are mapped to a unified local frequency space through a coordinate transformation matrix, non-uniform data are subjected to uniform reconstruction in combination with a self-adaptive interpolation algorithm, and the imaging resolution is remarkably improved. The frequency domain integration interval is effectively expanded, compared with a single-station I SAR which only covers a local area of the total rotation angle of the target, the range resolution is further optimized through multi-station bandwidth synthesis in the range direction, and high-fidelity reconstruction of the target in the complex shape is achieved.

The embodiment of the invention relates to the technical field of computer vision, in particular to an RGBT target tracking method based on frequency space enhancement and time adaptation, which comprises the following steps: obtaining a training sample set which comprises a plurality of video sequences, and each video sequence is composed of a visible light image and a thermal infrared image which are paired; constructing an RGBT target tracking model based on frequency space enhancement and time adaptation, wherein the RGBT target tracking model is composed of a frequency space enhancement network, a cross-modal feature extraction network and an online score prediction network; performing iterative training on the RGBT target tracking model based on the training sample set until convergence to obtain a trained model; and inputting the target video into the trained model to obtain a tracking result of the target video output by the trained model. According to the method, the coping capacity of RGBT target tracking in challenging scenes such as background interference and thermal crossover can be well improved, and the accuracy, efficiency and robustness of RGBT target tracking are effectively improved.

The invention provides an OTFS (Orthogonal Time Frequency Space) channel estimation method based on a bidirectional gating loop unit (BiGRU) and a multi-head attention mechanism, and belongs to the technical field of channel estimation. The method comprises the following steps: determining time delay-Doppler domain parameters according to a channel scene, and constructing a TDL (Tap Delay Line) channel model; designing a time-frequency domain pilot frequency structure; carrying out time-frequency domain modulation on a sending signal and adding high-power amplifier (HPA) nonlinear distortion; obtaining an initial channel state by using LS estimation; a BiGRU network and multi-head attention mechanism joint model is constructed, and channel state prediction is realized through bidirectional time sequence feature extraction and multi-dimensional attention weight distribution; and time delay-Doppler domain channel response reconstruction is completed by using the optimized model. Bidirectional dependency of channel time-varying features is captured through BiGRU, and a multi-head attention mechanism is combined to enhance the key path feature extraction capability, so that the channel estimation precision in a high-mobility scene is remarkably improved, and the influence of HPA nonlinear distortion on the system performance is effectively inhibited.

The invention provides a construction method and system of a non-reciprocal emission / absorption device with a Fizeau dragging effect. The construction method comprises the following steps: selecting a metal substrate, a dielectric grating and a two-dimensional material; applying a bias voltage in the x-axis direction to the two-dimensional material layer to generate a Fizeau dragging effect; the bias voltage is adjusted under TM polarization, so that the electron drift speed is close to the Fermi speed, asymmetric surface plasmon resonance is excited, and unequal emissivity and absorptivity are achieved; an adjustable singular point is generated in an angle-frequency space by adjusting the filling ratio of the grating, so that the numbers of spectral formants of emissivity and absorptivity near the singular point are different, and the wavelength integral nonreciprocity intensity is improved. The non-reciprocal heat radiation characteristic can be realized through voltage regulation and control without an external magnetic field.

The application discloses a large-scale PDE neural operator pre-training method based on a high-frequency enhancement module, a partial differential equation (PDE) data set is composed into a mixed data set, a large-scale PDE neural operator is constructed, preprocessed PDE data is mapped to a latent representation space through a space-time encoder, a frequency decomposition module is used for frequency space mapping, the frequency decomposition module includes parallel high-frequency branches and low-frequency branches, and high-frequency features and low-frequency features are obtained respectively; a multi-frequency fusion module (GFM) adaptively fuses the high-frequency features and the low-frequency features through a gating mechanism; finally, a prediction head is used for processing the fused features, and final output features, i.e., predicted physical features of a next time step, are obtained. The application firstly introduces an explicit frequency division and a high-frequency enhancement mechanism, the input field is divided into low-frequency and high-frequency parts, the low-frequency branches / high-frequency branches are used for processing respectively, and thus the model can simultaneously consider global trend modeling and local gradient detail reconstruction.

The invention provides an orthogonal time-frequency air conditioning communication system demodulation method based on deep learning. The method comprises the following steps: constructing an orthogonal time-frequency air conditioning communication system model and an interference model; according to communication system characteristics and anti-interference requirements, constructing a network structure combined by a convolutional neural network and a bidirectional long-short-term memory network; preprocessing the training data, and performing time sequence alignment on the input data and the label data; inputting the preprocessed data into a CNN (Convolutional Neural Network) to extract local spatial features, inputting the data into a combined network, capturing time-dependent features, calculating a mean square error loss function according to a predicted demodulation bit and a real bit, calculating a network parameter gradient by using a back propagation algorithm, and updating network parameters by using an optimizer according to the gradient; and carrying out model training until expected requirements are met. According to the invention, the advanced neural network architecture is innovatively combined, so that the communication reliability and robustness of the communication system in the interference environment are effectively improved.

The application provides a bridge damage assessment method and system caused by ship collision and a medium, and relates to the technical field of bridge health monitoring. The method comprises the following steps: collecting acceleration response signal arrays of different heights and positions of a bridge pier, and generating a time series matrix; drawing a time-frequency coherence spectrum under different base functions, and obtaining a coherence spectrum entropy; determining the optimal base function based on the information entropy principle; obtaining the local correlation coefficient of the time series matrix in the time-frequency space under the optimal base function, and drawing a time-frequency coherence spectrum; evaluating the correlation and dependence degree between time series according to the local correlation coefficient and the time-frequency coherence spectrum, and judging whether the ship-bridge collision damage occurs; if the collision damage occurs, calculating the time-frequency coherence damage factor of the time series matrix at different positions, and determining the collision position and the collision degree according to the maximum protruding value in the time-frequency coherence damage factor trajectory curve. The method can effectively separate the influence of environmental factors, and provides basic method support for establishing the ship-bridge collision damage assessment technology.

The present invention discloses a low-complex, reliable multidimensional orthogonal time-frequency space (ND-OTFS) modulation-based communication system for uplink and downlink wireless communication between resource-constrained Internet of Things (IoT) and machine-to-machine (M2M) devices comprising at least one transmitter configured to transmit bit stream involving N-Dimensional signal mapper and OTFS frame and at least one receiver configured to be integrated into said IoT or M2M devices, featuring a low-complexity detector for receiving the transmitted bit stream.

The invention discloses a vibration test and state monitoring method and system for an in-operation high-voltage circuit breaker, and the method comprises the steps: carrying out the energy propagation time sequence test of a multi-measurement-point vibration signal, constructing an energy flow direction topological graph, and precisely positioning a vibration source region through energy ratio analysis and path backtracking; acquiring a response time constant by adopting an impact response attenuation test, and converting a vibration source into a fault space positioning coordinate through space grid division and rate matching; a frequency-space mapping relation is established based on a fault position, and vibration characteristics are comprehensively described through peak frequency time sequence tracking and nonlinear component identification such as frequency multiplication, modulation and transient state; performing dispersion analysis on the continuous action impact peak value to form an action consistency deviation, and fusing a nonlinear feature set to quantitatively evaluate the mechanical degradation degree; the grading test density is generated according to the degradation state, the time period test unit is determined, the state grading test benchmark is established to realize mechanical state grade judgment, and the equipment operation reliability and the monitoring efficiency are improved.

The invention relates to an unmanned aerial vehicle physical layer secret key secret communication method based on an orthogonal time-frequency space. Comprising the following steps: establishing an unmanned aerial vehicle air-ground communication system consisting of a multi-antenna unmanned aerial vehicle base station, ground single-antenna legal users and ground passive eavesdropping illegal users; obtaining channel estimation vectors of all dominant paths by adopting a three-dimensional structured orthogonal matching pursuit algorithm; the method comprises the steps of obtaining a channel characteristic value of a communication channel through a path gain self-adaptive weighted moving average coding method, carrying out double-bit uniform quantization, carrying out Winnow key negotiation based on dynamic grouping and carrying out SHA-2 hash function confidentiality enhancement, and thus obtaining a physical layer key. According to the method, the channel dimension is converted through the orthogonal time-frequency space technology, the influence of Doppler frequency shift is effectively resisted, the channel reciprocity is improved, the key inconsistency rate is reduced, and the safety and stability of a communication system can be remarkably improved.

The invention relates to a frequency-space hybrid joint source channel coding method and an image transmission method. The method comprises the following steps: inputting an image to be transmitted into a joint source channel coder, and mapping the image into a channel input vector; an image block embedding module and a frequency space mixing module are sequentially arranged in each encoder layer of the joint source channel encoder, the frequency space mixing module independently divides a high-frequency feature and a low-frequency feature into two branches for parallel processing, and outputs of the high-frequency and low-frequency branches are spliced along a channel dimension and then are subjected to spatial feature modeling. The output of the frequency space mixing module is input into a next encoder layer; a channel adaptive attention mechanism is introduced into an encoder layer, real-time channel SNR is embedded into attention calculation of each encoder layer, and attention focuses are dynamically adjusted according to the real-time channel SNR. Compared with the prior art, the self-adaption to different channel signal-to-noise ratios is realized, and the reconstruction quality of two types of information of high-frequency texture and global semantics is effectively considered under the same code length.

The present disclosure proposes a precoding method, apparatus and device, and a storage medium, the method comprising: a sending device determining N layers of first signal streams needing to be sent in an orthogonal time-frequency-space OTFS system, N being a positive integer; converting the N layers of first signal streams from a time delay Doppler DD domain to a time frequency domain to obtain N layers of second signal streams; pre-coding the N layers of second signal streams to obtain M paths of third signal streams, wherein M is a positive integer; converting the M paths of third signal streams from a time-frequency domain to a time domain to obtain M paths of fourth signal streams; and sending the fourth signal stream to a receiving device. The embodiment of the invention provides a pre-coding method which can be applied to the OTFS system so as to successfully realize signal pre-coding in the OTFS system.

The application discloses a core RQD segmentation method based on frequency-space feature enhancement and long-distance dependence, comprising: spatial feature coding is performed on a core tank image to obtain output features, and a core feature map is determined; a morphological center axis of a core instance mask is extracted, and an accurate pixel length is calculated; a plurality of cores satisfying a core length threshold are screened, and a rock quality index in a region corresponding to the core tank is calculated. The application reduces technical bottlenecks such as loss of micro-fissure features, limited long-distance spatial dependence perception, discontinuous long-strip core segmentation and complex background interference in core segmentation; the average precision mean on the NEU-Rock dataset reaches 95.5%, which significantly reduces the parameter quantity and calculation amount compared with the prior art; and the core image can be converted into an accurate rock RQD index in real time and with high fidelity, thereby providing objective and robust digital support for mineral exploration and rock mass stability evaluation.

The application discloses a stratum absorption compensation method, system, device, storage medium and program product. The method comprises the following steps: converting an original seismic record into a frequency space domain seismic record; constructing a target function of a signal space prediction operator according to the frequency space domain seismic record and solving the target function to obtain a low-frequency signal space prediction operator; based on the frequency extendibility of the signal space prediction operator, a high-frequency signal space prediction operator is obtained by extrapolation of the low-frequency signal space prediction operator, and then a full-frequency signal space prediction operator is obtained; a full-frequency prediction error filter is obtained according to the full-frequency signal space prediction operator; and based on the full-frequency prediction error filter and the frequency space domain seismic record, a target function of stratum absorption compensation is constructed and solved to obtain an absorption-compensated seismic record. The application can inhibit the influence of noise interference on absorption compensation and improve the recovery precision of absorption compensation on seismic signals.

The application discloses a frequency-space domain alternating iteration seismic random noise suppression method and system, transforms a seismic signal from a time-space domain to a frequency-space domain, and obtains a frequency slice by taking data of a fixed frequency domain index; arranges the frequency slice into a Hankel matrix and performs singular value decomposition, selects singular values and corresponding singular vectors to perform rank reduction reconstruction on the Hankel matrix; obtains the reconstructed frequency slice, and takes the next frequency slice to complete spatial direction denoising; takes single seismic trace data of a fixed space domain index in the frequency-space domain data, arranges the single seismic trace data into a Hankel matrix and performs singular value decomposition, selects singular values and corresponding singular vectors to perform rank reduction reconstruction on the Hankel matrix; then, the reconstructed single seismic trace data is obtained through anti-diagonal average, the next seismic trace data is taken, the obtained frequency-space domain data after denoising is transformed back to the time-space domain, and a signal after noise suppression is obtained.

The invention discloses a large-scale PDE neural operator pre-training method based on a high-frequency enhancement module, and the method comprises the steps: forming a mixed data set through partial differential equation PDE data, constructing a large-scale PDE neural operator, mapping the preprocessed PDE data to a potential representation space through a space-time encoder, carrying out the frequency space mapping of the data through a frequency decomposition module, and carrying out the pre-training of the large-scale PDE neural operator. The frequency decomposition module comprises a high-frequency branch and a low-frequency branch which are parallel to obtain high-frequency features and low-frequency features respectively; the multi-frequency fusion module GFM adaptively fuses the high-frequency features and the low-frequency features through a gating mechanism; and finally, the fused features are processed through a prediction head, and final output features, namely predicted physical features of the next time step, are obtained. According to the method, an explicit frequency division and high-frequency enhancement mechanism is introduced for the first time, an input field is decomposed into a low-frequency part and a high-frequency part, and a low-frequency branch and a high-frequency branch are adopted for processing, so that the model can give consideration to global trend modeling and local gradient detail reconstruction at the same time.

The invention discloses a strain clamp X-ray image enhancement and defect identification method and system, and belongs to the technical field of image processing. The method comprises the following steps: acquiring an internal image of a wire clamp through X-rays, and performing feature reconstruction and defect modeling in a frequency space and a potential space; a multi-scale frequency encoder is adopted to extract detail features of a tension clamp image, a frequency domain structure selection module is combined to enhance defect edge response, and finally robust identification of an abnormal region is realized in a potential diffusion process. Therefore, good defect detection precision and boundary definition can be kept under the complex conditions of strong background noise interference, low image contrast and the like.

The invention belongs to the technical field of relay protection of a power distribution network of a power system, and provides a single-phase broken line grounding fault detection method for an ungrounded neutral system, which comprises the following steps of: 1, acquiring three-phase current signals of each feeder line; step 2, performing morphological filtering processing on the acquired negative sequence current signal; step 3, mapping the filtered negative sequence current signal to a time-frequency space with u as a variable; 4, searching an optimal twiddle factor according to the energy focusing characteristic of the time-frequency current signal; according to the method, the symmetric component method, the morphological filtering and the coordinate transformation technology are combined, so that the accuracy and the stability of single-phase broken line grounding fault feature extraction of the neutral ungrounded system are remarkably enhanced, and the precision and the reliability of fault detection are greatly improved; and meanwhile, the optimal twiddle factor is adaptively determined based on the feeder energy concentration ratio, so that the detection strategy can flexibly adapt to different fault conditions, and the fault detection efficiency and success rate under a complex power grid structure and variable operation conditions are effectively improved.

The invention discloses a distributed photovoltaic aggregation frequency modulation standby optimal configuration method considering node frequency security constraints under transmission and distribution cooperation. The method comprises the following steps: describing uncertainty of photovoltaic aggregation frequency modulation capability by using a Gaussian mixture model, and establishing a power transmission network node frequency response model containing frequency space distribution characteristics; taking minimization of system power generation and frequency modulation reserve cost as a target, and combining opportunity constraint planning to construct an optimal configuration model; a response model is reduced based on a frequency divider theory, a Bernstein polynomial approximates frequency dynamics, and a differential algebraic equation is converted into an algebraic equation; then, binary expansion and Gaussian mixture model linear invariance are utilized to convert the model into a mixed integer linear programming model, and Bernstein polynomial convex hull property tightening constraint is combined; and finally, solving the model to obtain the optimal photovoltaic aggregation frequency modulation reserve capacity and control parameters. The frequency space distribution is accurately described, the problem of insufficient frequency safety risk identification is solved, and the frequency safety level of a power system is improved.

The invention relates to the technical field of signal processing, in particular to a multi-dimensional signal simulation generation method based on user interface control, which comprises the following steps: S1, creating a three-dimensional visual coordinate system; s2, capturing a frame selection operation of a user in a three-dimensional coordinate system, and generating a dynamic coupling relation matrix; s3, cutting an original signal flow into N signal slice units according to the dynamic coupling relation matrix established in S2; s4, waveform recombination is carried out on the signal slice units generated in the S3, and recombination coupling signal flow is formed; and S5, decomposing the recombined coupling signal flow generated in the S4 into a time signal layer, a frequency signal layer and a space signal layer. According to the method, the dynamic coupling relation matrix is constructed, and the parameters of the frequency and the space slice are adjusted in real time, so that the precision and the flexibility of multi-dimensional signal simulation are effectively improved, and the consistency and the coordination of the signals in the time-frequency space are ensured.

The application relates to a kind of orthogonal time-frequency space (OTFS) signal detection methods based on message selective transmission, suitable for high-speed mobile communication scene.The application first adds the calculation of symbol log-likelihood ratio (LLR) on the basis of original MP detection algorithm, improves the accuracy of message transmission, and optimizes the factor graph structure by introducing edge grouping strategy to group edges with different channel coefficients, reduces the influence of loop effect on detection performance.Then, a damping factor is introduced in the iteration process to control the message oscillation amplitude in each iteration and accelerate the convergence speed of the algorithm.During the detection process, the D-MsP detector further improves the detection performance and convergence efficiency of the OTFS signal in the multipath channel by using the sparsity principle.The D-MsP detector achieves a good balance between performance and computational complexity, significantly reduces the computational overhead while ensuring high detection accuracy, and is particularly suitable for high-speed mobile communication scenarios.

A transmission station that performs wireless communication with a receiving station at a predetermined carrier frequency performs orthogonal frequency division multiplexing on a symbol sequence, performs orthogonal time frequency space multiplexing on a symbol sequence, performs switching between orthogonal frequency division multiplexing and orthogonal time frequency space multiplexing to input a symbol sequence obtained by mapping a bitstream to only one of them, obtains a relative velocity between the transmission station and a receiving station, controls the switching based on a velocity; and transmits a switching notification that is a control signal to the receiving station, when the switching is controlled.

This invention relates to a method for secure physical layer communication for unmanned aerial vehicles (UAVs) based on orthogonal time-frequency space. The method includes the following steps: establishing an UAV air-to-ground communication system consisting of a multi-antenna UAV base station, a legitimate ground-based user with a single antenna, and an unauthorized ground-based user passively eavesdropping; obtaining channel estimation vectors for all dominant paths using a three-dimensional structured orthogonal matching pursuit algorithm; obtaining channel eigenvalues ​​of the communication channel using a path gain adaptive weighted moving average coding method; performing double-bit uniform quantization; and enhancing security through Winnow key negotiation based on dynamic grouping and SHA-2 hash function, thereby obtaining the physical layer key. This invention effectively combats the effects of Doppler shift by transforming the channel dimension using orthogonal time-frequency space technology, improving channel reciprocity, reducing key inconsistency rate, and significantly improving the security and stability of the communication system.

A method and apparatus are disclosed to reduce MU-MIMO complexity in a receiver. In one embodiment, a method implemented in a network node includes determining a frequency dispersion of a channel for a wireless device (WD); and based at least in part on the determination of the frequency dispersion, determining at least one frequency spacing for at least one weight associated with the channel. In another embodiment, a method implemented in a WD includes transmitting a signal to the network node; and receiving an allocation of at least one time-frequency resource based at least in part on a determination of a frequency dispersion on the transmitted signal, the at least one time-frequency resource being shared between the WD and at least one other WD.

The invention provides a communication method, device and system, equipment and a storage medium, and belongs to the technical field of communication. The method comprises: a network device sending a synchronous broadcast block (SSB) signal to a terminal, the SSB signal being converted from a time delay Doppler (DD) domain of an orthogonal time frequency space (OTFS) system to a time frequency domain of an orthogonal frequency division multiplexing (OFDM) system. Therefore, the SSB is mapped in the delay-Doppler DD domain to be sent and received, and meanwhile, the reliability and accuracy of fast and frequent signal switching in a high-speed moving scene are ensured.

A communication frame for an Orthogonal Time-Frequency Space (OTFS) transmission system includes at least one first type block and at least one second type block. The first type block comprises data signals arranged in a two-dimensional pattern along the delay and Doppler domains, wherein at least one data signal has a superimposed pilot signal. The second type block comprises data signals arranged in a two-dimensional pattern along the delay and Doppler domains, which may or may not have a superimposed pilot signal. At least one second type block is surrounded by a first type block in the delay domain, and one or more first type blocks surrounding the second type block have at least one identical data symbol and an associated identical superimposed pilot symbol at the same position in the two-dimensional pattern. An OTFS transmitter generates and transmits the communication frame, and a receiver utilizes its characteristics for oscillator frequency offset compensation and channel estimation.

The present disclosure relates to a channel estimation method based on orthogonal time-frequency-space modulation technology. The method comprises establishing a model of orthogonal time-frequency-space channel estimation, which comprises a time-delay Doppler domain received signal, a sparsity adaptive matching pursuit algorithm and a denoising network; processing the time-delay Doppler domain received signal by using the sparsity adaptive matching pursuit algorithm to reconstruct a delay Doppler domain channel; and inputting the delay Doppler domain channel into the denoising network for denoising processing to obtain a denoised channel response. The method can reconstruct the delay Doppler domain channel without relying on prior information of the number of channel paths, and can eliminate the corresponding noise of the delay Doppler domain channel.

The present invention discloses a SSVEP-BCI device based on frequency space multiplexing and a target recognition method thereof. The SSVEP-BCI device of the present invention comprises N array-shaped F The stimulation interface is composed of eight intermediate units, each of which is composed of two rows and two columns of minimum units. Each minimum unit is a stimulation module that flashes at a single frequency. The stimulation frequency within the intermediate units is the same, and the difference in stimulation frequency between any adjacent intermediate units is the same. Within the effective area of the stimulation interface, the eight neighboring minimum units of any target minimum unit form differentiated competitive stimulation neighbors. This invention is based on the multi-target SSVEP-BCI paradigm of frequency-spatial multiplexing, utilizing a certain number of available frequencies to achieve effective stimulation exceeding the number of frequencies. Based on frequency-spatial multiplexing within a limited space, it can achieve more separable response signals, thereby improving interaction efficiency.

The invention relates to OTFS-based communications with improved resource allocation. An orthogonal time-frequency space (OTFS) communication method for communicating between a user equipment (UE) and a base station (BS) is provided. The OTFS communication method comprises the step of transmitting (103), in particular by the UE, a report comprising a delay and a Doppler shift to the BS.