95 results about "Time domain model" patented technology

The invention discloses a method and a device for eliminating multi-symbol subcarrier jamming and performing channel estimation jointly. The method comprises the following steps of: obtaining a slope matrix of a multipath channel by utilizing two pilot frequency data successively received on a same subcarrier; obtaining a nodal increment matrix of the multipath channel by utilizing the pilot frequency subjected to slope matrix removal; and determining a time-domain model of the multipath channel for channel estimation by utilizing the slope matrix and the nodal increment matrix. According to the method, the time-domain model of the multipath channel is established, so that the frequency response of each subcarrier channel can be accurately obtained, and the subcarrier jamming can be effectively eliminated.

The invention belongs to the field of integrated circuits, and relates to an interconnection line model reduction method based on time-domain trapezoidal method difference. The method comprises the steps as follows: reading performance data of an interconnection circuit, utilizing an improved node voltage method to build a corresponding time-domain equation; utilizing a trapezoidal method to discretize the time-domain equation of the interconnection circuit and obtain a nonhomogeneous recurrence relation; using a nonhomogeneous Arnoldi algorithm to construct a projection matrix, and then using the projection matrix to perform contragradient transformation on the time-domain equation of the interconnection circuit to obtain a reduction system; and finally, using the trapezoidal method to discretize the reduction system to obtain time-domain output. By virtue of the method, the matching of state variables between the reduction system after the time-domain trapezoidal method difference and the original system is ensured; the time-domain reduction precision is ensured; and the numerical stability during the reduction process and the passivity of the reduction system are ensured. Compared with the original time-domain model reduction method, the computing complexity is greatly reduced; and the method has higher precision in time-domain compared with a frequency-domain reduction method.

The invention belonging to the field of medical imaging provides a frequency-domain-based method for lipid and water suppression treatment of magnetic resonance spectrum imaging data. The method comprises: one-dimensional Fourier transform is carried out on collected single voxel magnetic resonance spectrum time-domain data to obtain a frequency-domain FID signal; according to prior knowledge, four lipid peaks and one water signal frequency range are determined; a nonlinear parameter attenuation coefficient in a spectrum time-domain model by using a singular value decomposition method; on the basis of a spectrum peak frequency in the prior knowledge and the attenuation coefficient obtained by quantification, the amplitude and phase of a linear parameter are estimated by using an amplitude-phase adaptive FIR filtering method; the frequency range is changed and the previous two steps are executed circularly until quantification of the four group of lipid and water signal parameters is completed; the time-domain FID model and the lipid and water signal quantification parameters form lipid and water time-domain signals; and one-dimensional Fourier transform is carried out on the time-domain signals, difference processing is carried out on the frequency domain and an original spectral signal, thereby obtaining magnetic resonance spectrum imaging data after lipid and water suppression treatment.

The invention discloses a passive synthetic aperture-based multi-unmanned aerial vehicle cooperative direct positioning method. The method comprises the following steps of: establishing an array signal time domain model related to arrival signal complex envelope, carrier phase and Doppler frequency offset based on a plurality of unmanned aerial vehicle array receiving models; each unmanned aerial vehicle arranges array signal time domain data according to a time sequence to form an expanded array signal time domain model based on a passive synthetic aperture thought, and converts the expanded array signal time domain model into frequency domain data by using a radix-2-FFT algorithm; the central station forms frequency domain data into a multi-machine frequency domain observation vector, establishes a mathematical optimization model for joint estimation of a target position vector and a propagation coefficient according to a subspace orthogonal criterion, extracts an information matrix only containing a target position, and performs grid search of multiple regions by taking a minimum characteristic value of the minimum information matrix as a target; and accurate positioning of multiple targets is realized. According to the method, the multi-target positioning precision and the multi-target resolution capability can be remarkably improved, and the problem of data association in the multi-target positioning process can be avoided.

The invention provides an optical imaging device and method for the mammary gland based on image segmentation and time-frequency information fusion and belongs to the technical field of near-infraredoptical chromatography imaging. The method comprises the steps that firstly, radiation intensity information in all directions of the boundary of the to-be-detected mammary gland tissue under the function of a frequency modulation laser and a pulse laser is acquired, and by simulating the infrared radiation transmission process in the to-be-detected mammary gland tissue under the function of the frequency modulation laser, a reconstructed image for optical parameter distribution under a frequency domain model is primarily obtained; then, a threshold value division method is used for dividing the reconstructed image, an optical parameter distribution initial value of a target area of a time-frequency model is obtained, and by simulating the infrared radiation transmission process under thefunction of the pulse laser, an internal structure of a target area of the mammary gland tissue is obtained. According to the optical imaging device and method, the problem is solved that in the priorart, in the reconstruction process for optical distribution of the mammary gland, a measurement signal of a single model is used for reconstruction, and the reconstruction precision or efficiency islow. The optical imaging device and method can be applied to reconstruction of a high-efficiency and high-precision mammary gland detection optical parameter field.

The invention relates to a generalized state space average modeling method based on aircraft electric power system dynamic characteristics. The method includes the steps that time-variant nonlinear differential equations of all links of an aircraft electric power system are built according to an aircraft electric power system structure; state variables are determined according to the differential equations in the above step, Fourier decomposition is conducted on the state variables, and the state variables described by the Fourier coefficients are obtained; the obtained Fourier coefficient state variables are substituted into the differential equations, and a generalized state space average model of the aircraft electric power system is obtained; the dynamic characteristics of different time scales of the aircraft electric power system are analyzed according to different flying working conditions of an aircraft; the generalized state space average model of the aircraft electric power system is simplified according to the dynamic characteristics. The generalized state space average modeling method has the advantages that by means of the method, the operating working conditions and dynamic characteristics of the aircraft electric power system can be discriminated, a time domain model can be replaced in system analysis and design, the time domain model can be simplified into the state space average model in the steady state, good engineering accuracy is achieved, fast analysis ability is achieved as well, and the generalized state space average modeling method is suitable for the field of steady state and transient state analysis of different aircraft models.

The invention discloses a method for predicting the energy consumption of a hybrid truck based on a variable time domain model, and the method comprises the steps: repeatedly operating the hybrid truck in an urban working condition at a test stage, obtaining the original operation data of the truck, carrying out the preprocessing, carrying out the classification through a k-means clustering algorithm, and generating a plurality of state segments; establishing a Makarov working condition prediction model, and providing a plurality of prediction time domains for each state segment to obtain predicted vehicle speeds in the prediction time domains; calculating and recording the actual vehicle speed of the vehicle, and selecting the prediction time domain with high prediction precision as the parameter of the state segment; in the application stage, according to the characteristic parameters of normal running of the truck, the prediction time domain corresponding to the working condition with the high matching degree in the state fragments under the cyclic working condition is found to serve as the prediction time domain under the running working condition, and energy consumption is obtained according to the Makarov working condition prediction model. According to the prediction method, timely adjustment of the prediction time domain can be realized, and the calculation burden is not increased too much while the vehicle speed in the time domain is predicted more accurately.

Embodiments of a method for implementing a finite difference time domain modeling with multiple APCs (107) are disclosed herein. The disclosed methods and systems overcome the memory capacity limitation of APCs by having each APC perform multiple timesteps on a small piece of the computational domain or data volume in a APC queued manner. The cost of transferring data between host and compute accelerator can then be amortized over multiple timesteps, greatly reducing the amount of PCI bandwidth required to sustain high propagation speeds. The APC queued nature of the algorithm achieves linear scaling of PCI throughput with increasing number of APCs, allowing the algorithm to scale up to many dozens of APCs in some embodiments.