34 results about "Decomposition theory" patented technology

The invention discloses a tensor subspace continuous system identification method of a bridge time-varying system. The method comprises the following steps: acquiring a bridge time-varying signal; dividing the time-varying signal with the signal time history of T into N time windows according to an increasing step length L to obtain Hankel matrixes of the N time windows; establishing a mathematical model for solving a tensor subspace system matrix, wherein Xk=UkSkV<T>+Wk; and solving the tensor subspace system matrix to obtain the frequency fi, k and damping ratio zeta i, k of the ith-order vibration mode of the kth time window and the vibration mode vectors phi k of all orders. According to the invention, the time dimension is introduced; expanding the two-dimensional matrix to a three-dimensional tensor; a time-varying Hankel tensor is established, based on tensor expansion and tensor rapid parallel decomposition theories, system matrix rapid estimation based on tensor operation is realized, calculation efficiency and identification result precision can be improved, modal parameter information of a system can be identified more easily, and a core technical support is provided forreal-time health monitoring of a bridge.

The invention discloses a multi-material decomposition method for a single-energy-spectrum CT image. The multi-material decomposition method comprises the following steps: (1) acquiring the single-energy-spectrum CT image; (2) aiming at a CT image, constructing a decomposition target function comprising a data fidelity term and three penalty terms according to a CT image domain multi-material decomposition theory, wherein the data fidelity term ensures that the error between the measured value and the true value is as small as possible, in the three penalty terms, the first term uses a total variation term to ensure the piecewise constant characteristic of a CT material image, the second term uses a 0 norm term to ensure the sparsity of materials in the CT image, and the third term uses afeature function term to ensure that a multi-material decomposition result meets the constraint that the volume fraction is 0-1 and the sum of the volume fractions of all the materials is 1; and (3) solving an initial value of the target function by adopting a matrix inversion method based on dual-material hypothesis, and solving the target function by adopting an alternating direction multipliermethod, so that accurate decomposition of various materials under single-energy common CT is realized, and the decomposition precision is equivalent to that of dual-energy CT.

The invention relates to a dynamic operation water level control method for a 3D or higher cascaded reservoirs in flood season. The method comprises the steps that 1) the relation of upper pre-impounded water level limits among the 3D or higher cascaded reservoirs is analyzed on the basis of an aggregation-decomposition theory and a pre-impounding pre-discharge method; 2) an optimized scheduling module which takes the minimal flood prevention risk rate, the minimal under-generation risk rate and the minimal under-impounding risk rate in the effective forecast period of a flood forecast as target functions, the operation water level in the flood season as a decision variable, and a manual fish swarm algorithm as an optimized solution algorithm is established, a non-inferior solution set is provided for dynamic operation water level control in the flood season, and a decision scheme set is provided for a multi-target decision module; and 3) the multi-target decision module which takes the minimal flood prevention risk rate, the minimal under-generation risk rate, the minimal under-impounding risk rate, the maximal generation capacity and the maximal impounding rate as evaluation indexes and a network analysis method as a multi-target evaluation method is established, and a preferable decision scheme of the dynamic operation water level control in the flood season is selected. Thus, theoretical basis and technical support are provided for scientifically making a combined dynamic operation water level control scheme for the cascaded reservoirs in the flood season.

The invention belongs to the field of on-line monitoring technology of insulative condition of SF6 (sulfur hexafluoride) gas insulated electric equipment, and in particular relates to a gas insulated electric equipment partial discharge multi-source joint detection method. The detection method mainly comprises the steps of preparing a test, cleaning a stainless steel cylinder, filling with SF6 gas, performing an industrial frequency AC SF6 gas PD test, pulse current detection, ultrahigh frequency sensor detection, fluorescent optical fiber sensor detection, discharge gas collection and component detection and the like. The detection method provided by the invention is simple in operation, liable to promote, and provides references for multi-dimensional information joint detection method. The detection method is widely applied to SF6 gas insulated electric equipment partial discharge multi-sensor joint detection under the condition of power frequency, and provides a simple test scheme for multi-dimensional information extraction of PD (Potential Difference) decomposition characteristics and a decomposition theory.

The invention discloses a method for quickly estimating underwater target shell radial vibration low-frequency sound radiation signals based on mode decomposition, and belongs to the technical field of underwater target sound radiation. The method includes the following steps that firstly, based on uncertainty of a researched object, the range of researched frequency bands is determined; secondly, based on a mode decomposition theory and different model structures, a simulation sound pressure equation is determined; thirdly, based on a mode truncation theory, an appropriate lower order axial mode order is calculated by adopting a higher circumferential mode order; fourthly, an appropriate lower order circumferential mode order is calculated by adopting a higher axial mode order; eventually the radiation signals through simulating calculation are acquired through calculation, and then the underwater target sound radiation condition is analyzed. According to the technical scheme, the underwater target sound radiation signals generated by radial vibration are accurately simulated through the few mode orders, and therefore calculation complexity is low and accuracy is high.

The invention provides a power-distribution-network single-phase grounding fault positioning method based on matching pursuit. The method is characterized by carrying out sparse expression on a transient grounding current through an atomic sparse decomposition theory; extracting an attenuation direct current component to divide a fault path; and further positioning a fault point. By using an adaptive atomic sparse decomposition theory, the limitations of a traditional non-adaptive algorithm can be avoided and a signal description range is enlarged, and the method is suitable for complex grounding transient signal decomposition. Through matching a tracking algorithm, an attenuation direct current component can be rapidly and accurately extracted, and on-line section positioning is realizedthrough combining a power distribution network topology structure.