104 results about "Random waves" patented technology

The invention discloses an analysis method for reducing rolling motion of a ship. The analysis method comprises the following steps of according to an established three-dimensional stimulation image of the ship, calculating instant restoring force and instant wave incidence force of the ship under any waves, calculating a rolling angle and a ship rolling probability according to the ship heaving, pitching and rolling three degrees of freedom coupling motion differential equation to obtain the probability that the rolling angle of the ship is smaller than a flooding angle, thereby judging whether the ship runs at a safe state; and by regulating a navigational state of the ship, obtaining a numerical simulation result of the motion of the ship in any wave directions under the action of random waves and the probability that the rolling angle is smaller than the flooding angle, so that a navigation state of the ship corresponding to the maximum of the probability that the rolling angle is smaller than the flooding angle can be found out, and the rolling motion of the ship can be reduced by selecting the navigation state or changing the model line of a ship body at a design stage. According to the analysis method for reducing the rolling motion of the ship, which is disclosed by the invention, the rolling angle and the rolling probability are calculated, so that the rolling motion of the ship under any waves is reduced.

The invention relates to a novel frequency domain ground-to-air electromagnetic prospecting method which adopts a work mode of land launching and air receiving of electromagnetic waves to extract signal frequency spectrums and gives the underground electrical structure an inverse interpretation through a whole-region apparent resistivity method. A launching system which works on the ground launches multi-frequency pseudo-random waves towards the underground through multiple cascades and the signal with multiple frequencies can be obtained with one triggering, thereby greatly improving the detection efficiency. A receiving system is loaded on an aircraft, so when measuring the magnetic fields in the testing zone, it can adapt to the environment of complex surface structures, reduce the static effect caused by the near field effect and expands the detection range of electromagnetic prospecting. The receiving system can correct and compensate tested magnetic-field components when measuring multiple magnetic-field components, so the resolution capability of magnetic field measurement is improved. The frequency domain ground-to-air electromagnetic prospecting method is applicable to depth detection of severe surface zones and has the advantages of being wide in detection range, large in detection depth, high in detection efficiency, etc.

The invention discloses a device for simulating liquid sloshing generated under the random wave action. The device comprises a computer, a data collection module, an irregular wave generation module, a connecting rod, a base, a movement mechanism fixed to the base, a table board, a liquid cabin fixed to the table board, and a particle imaging velocimetry system. The particle imaging velocimetry system is right opposite to the front face of the liquid cabin, the irregular wave generation module is connected with the table board through the connecting rod, and the table board stably and transversely moves on the movement mechanism. The device further comprises a digital pressure sensor, a strain sensor, a wave height meter, a displacement sensor and an acceleration sensor. The digital pressure sensor and the strain sensor are embedded to the inner wall of the liquid cabin, the wave height meter is installed inside the liquid cabin, one end of the displacement sensor and the acceleration senor are installed on the table board, and the other end of the displacement sensor is fixed to the base. The device can accurately stimulate liquid sloshing generated under the random wave action in a small room.

This invention relates to one high speed random wave generator based on FPGA, which adopts DDS technique with data sample rate more than 1GHz and comprises CPU, parallel data phase generation part, wave shape memory part, plug and filter part, parallel and series conversion circuit and DAC, wherein, the parallel data phase generation adopts parallel process to generate multiple data phase In one time clock to get multiple data; then it uses FPGA series and parallel conversion circuit to output the data to DAC into virtual volume.

The invention discloses a randomized beam forming method and the system on the basis of a multi-antenna receiver, which aims at limiting each receiver to obtain at most one beam, wherein each beam is respectively carried out merger of maximum signal-to-noise ratio (SINR) by the receiver, and feedback antenna which is merged obtains CSI of an equivalent channel. The system which is compared with a randomized beam forming system of a single antenna receiver is not added feedback cost of the system. A precoding mode, CSI feedback content and a dispatching mode of the whole system are completely same as the multi beam system of the single antenna receiver on the basis of a base station. The invention greatly increases throughput of the randomized beam forming system under the premise that CSI feedback quantity is not added.

Thrusters in communication with a feedback control system are provided on a cylindrical offshore marine member, such as a spar, for reducing and / or controlling vortex-induced-vibrations, low-frequency drift oscillations due to random waves, and low-frequency wind induced resonant oscillations. The thrusters are provided thrust instruction from the feedback control system based on marine member displacement and current velocity.

The invention discloses a wave power device. The wave power device comprises at least two wave energy conversion units, a turbine, a pipeline and a generator; the turbine and the generator are arranged in the pipeline; a generator shaft is fixedly connected with a turbine shaft; the upper end of the pipeline is communicated with the wave energy conversion units; each wave energy conversion unit comprises a floater, a connection rod, an upper check valve, a lower check valve, a cylinder body and a piston; the connection rod is fixedly connected between the floater and the piston; the upper check valve is arranged on the piston; the lower check valve is arranged on a bottom plate of the cylinder body; the lower end of the cylinder body is in sealing connection with the pipeline; and all the wave energy conversion units are communicated with the upper end of the pipeline respectively. Each wave energy conversion unit can work independently and stably, can collect the random wave energy in a large scale, and provides the wave energy for the generator for stable power generation, and the power generation efficiency can be adjusted by adjusting the number of the wave energy conversion units.

The invention relates to the field of acoustics, in particular to a method for quickly calculating characterization and transfer of uncertainties of marine environment and sound fields. The invention aims to solve the problems of random spectrum characterization of uncertain environmental parameters and uncertain sound pressure fields and whether to transfer the uncertainties form the environmental parameters to the sound pressure fields. The method comprises the following steps of: establishing a domain space taking the known quantity as a center for the uncertain environmental parameters and the uncertain sound pressure fields respectively; performing the probability density function description on the uncertain quantity; and chaotically carrying out the random spectrum characterization according to a polynomial taking the probability density function as the uncertain quantity, and further combining the chaotic random spectrum characterization of the polynomial and a certain wave equation, educing the random wave equation embedded with uncertainty, acquiring the system of partial differential equation of uncertain coefficients, and finally acquiring the uncertain sound pressure fields formed by the linear superposition of the chaos based function of the uncertain coefficient weighting polynomial. The method has the advantages that: the acquired uncertain sound pressure fields are the same as the result acquired by MonteCarlo, and the calculating speed of the method is improved by more than 10 times.

The invention discloses a band ratio method based maize embryo segmentation method in a high-spectral reflection image. The high-spectral image of a maize seed is collected with the embryo surface of the seed upwards; multiple pixels and spectrums thereof are extracted from the endosperm and embryo and normalized; the spectral ratio of two random wave bands is calculated and serves as the band ratio, and the optimal band ratio is selected; a band subset is selected, variance of all pixels in the band subset is calculated, a seed binary image is obtained via threshold segmentation, and a background removed high-spectral image of the maize seed is obtained via mask operation; and a gray scale image of the background removed high-spectral image of the maize seed under the optimal band ratio is calculated via the high-spectral image, the gray scale image is segmented in a region growing method to obtain an embryo binary image, the embryo binary image is processed to obtain a seed embryo binary image, and the high-spectral image of the maize seed embryo is obtained via mask operation. The method can be used to segment the maize seed embryo in the visible near-infrared high-spectral image effectively, the segmentation effect is good, and the practicality is higher.

An optical fiber containing one or more random modulations capable of reflecting one or more random wavelengths of light passing through the optical fiber is provided. Each modulation is a section of the optical fiber in which the refractive index has been modified or a section of random refractive index optical fiber that has been spliced into the optical fiber. The optical fiber is produced by modifying the refractive index of at least one portion of the optical fiber through photo-etching, photo-bleaching, ultraviolet radiation exposure or splicing. The optical fiber containing the random modulation is used to measure one or more engineering parameters by locating the section or portion of the optical fiber containing the random modulation in an area where the engineering parameter is to be measured and measuring the engineering parameter using optical frequency domain reflectometry.

The invention discloses an FPGA-based DDS random waveform signal generator. The random wave form realization mode of a conventional signal generator is online generation and downloading. A random waveform module is additionally arranged in such a mode, as a result, the cost is increased and inconvenience is brought to users. The conventional signal generator can merely realize signal reproduction and cannot well optimize a frequency spectrum. In the FPGA-based DDS random waveform signal generator, a whole system-on-a-chip comprises an embedded phase-locked loop, a one-out-of two data selector with a bit width of ten, a one-out-of-four data selector with a bit width of eight, a first accumulator A with a bit width of thirty two, a second accumulator B with a bit width of thirty two, a ROM_triangular wave on a chip, a ROM_square wave on a chip, a ROM_sine wave on a chip, a ROM_random wave on a chip, a scrambling generator and an NIOSII core. The FPGA-based DDS random waveform signal generator has the advantages of high versatility, simple control operation, and frequency spectrum optimization.

The invention belongs to the technical field of hyperspectral remote sensing image classifying, and relates to a hyperspectral remote sensing image classifying method based on hierarchy ensemble learning to solve the problem that hyperspectral remote sensing image data are low in classification precision. The method mainly comprises the steps that two layers of integrated structures are used for classifying hyperspectral images and include an inner structure and an outer structure; in the inner structure, spectrum sets with differences are formed through random wave band selection; the spectrum sets serve as a unit, training is carried out through an Adaboost integrating method, and testing samples are classified; in the outer structure, the classification results of the spectrum sets in the inner set are integrated, and the final classification of the samples is determined through a weighted voting method; the whole image serves as a testing sample, the whole image is classified, and then a classified topic image is obtained. The method is used for classifying the hyperspectral remote sensing image.

The present invention relates to a kind of equipment capable of collecting marine wave energy in large scale and making power generation, belonging to the field of marine wave energy collection and application. Said invention is aimed at adopting several mechanical wave energy collection units to collect wave energy, utilizing related equipment to centralize the random wave energy of sea area with a certain scale and provide said wave energy for every power generator to implement direct stable power generation and utilizing energy-storage and energy-release equipment to regulate power of power generation. Said invention also provides the concrete structure of its marine wave energy collection and power generation equipment.

Disclosed is an obtaining method of measurement matrixes of a compression spectral imaging system based on random wave front phase modulation. When the method is used for obtaining the measurement matrixes of the compression spectral imaging system based on random wave front phase modulation, a broadband hot light source, a spectral filtering device, a pinhole diaphragm and a magnification imaging lens need to be added in a light path of the system. According to the obtaining method, the translation invariance of the local space of the compression spectral imaging system based on the random wave front phase modulation is used, and the measurement matrixes of the system are obtained through low measuring frequency; a high-contrast-ratio speckle field is obtained through the method that speckle light intensity distribution on an original detection face is magnified and imaged onto a detection face, and the signal to noise ratio of the measurement matrixes is increased.

The invention provides a high speed trimaran pitch reducing control method based on a fuzzy control method. According to the method, a random wave model with the adding of an encounter frequency is introduced, random wave is taken as a system input, an ANSYS platform is used to analyze and obtain a trimaran hydrodynamic coefficient, a high speed trimaran longitudinal motion mathematical model is established according to the hydrodynamic coefficient, a membership function of a fuzzy control method is designed for the trimaran model, an input quantity is mapped as a fuzzy set of an input domain through the membership function, thus a 7*7 trimaran fuzzy control rule is designed, an incident flow attack angle change amount of a pitch reducing appendage is dynamically controlled according to a control rule, thus longitudinal force and torque provided by the pitch reducing appendage to a trimaran are controlled, longitudinal swing brought by waves is offset to the maximum, and the longitudinal swing reduction control of the high speed trimaran is realized. According to the high speed trimaran pitch reducing control method, a ship heaving height and a longitudinal swing angle in a motion process are reduced, and the stability and passenger comfort in the trimaran high speed operation process can be effectively controlled and improved.

The invention discloses a precoding feedback method, a system, user equipment and a base station. The method comprises the following steps of: receiving a random wave beam information flow and determining an optimal wave beam assembly according to the signal-to-interference and noise ratio of the random wave beam information flow; obtaining a feedback threshold value; and feeding back the information of at least one wave beam the signal-to-interference and noise ratio of which is higher than the feedback threshold value in the optimal wave beam assembly. By the embodiment of the invention, the feedback quantity during precoding can be lowered.

The invention discloses a method for identifying a common digital modulation signal based on cyclic spectrum correlation. The reliability of signal analysis is improved by utilizing the noise-proof feature of a signal cyclic spectrum; the steps of alpha section wavelet de-noising and averaging through superposition are introduced into a calculation process of a signal spectral correlation function, so that the random fluctuation caused by the limited sampling number and the external disturbance in an original spectrum correlation estimation algorithm result is effectively weakened to facilitate identification and extraction of modulation features; and meanwhile, an alpha section and an f section of an obtained spectral correlation diagram are computed by utilizing signal spectral correlation, and appropriate features and parameters (such as a ratio of maximum absolute values of spectral correlation functions, namely the alpha section and the f section, the number of intense lines of the alpha section, a coefficient of fluctuation of the alpha section, the normalized area of the f section, a predominance ratio of spectral lines of the alpha section and the like) are selected to construct a classification method to identify the modulation mode of the communication signal.

The invention relates to the technical field of mechanical testing equipment, in particular to a fatigue durability testing device, and solves the problem that an automobile transverse stabilizer bar product is subjected to fatigue durability test under various working conditions. The fatigue durability testing device comprises a power device. A torsion driving cylinder is arranged in the power device. An output end of the torsion driving cylinder is provided with a torsion driving swing arm. The torsion driving swing arm is of a strip bar structure, is vertical to the axial center line of the torsion driving cylinder and is eccentrically arranged. The transverse stabilizer bar is provided with two pieces in the horizontal direction. The torsion driving cylinder can load a sinusoidal waveform, triangular wave, random wave or path spectrum signal under the control of a computer. By using the fatigue durability testing device, the test is stable and the efficiency is high. Various actual using working conditions are simulated. The comprehensive cost is relatively low.

This invention is a sort of DDS signal generator and control method of wave storage deepness, the space deepness of wave storage is set according to the wave data length, and it makes the wave data to be deposited to the wave storage space of the corresponding deepness. A wave data of this wave storage space progresses the exterior storage according to the stated order. It obtains the wave data length of the exterior storage. It accumulates the wave data length of the next wave data point according to the corresponding position of the initiative wave data point of the wave data of the exterior storage. It mappings this corresponding address to the wave data address of the exterior storage according to this wave data length. It makes the wave data of the exterior storage to be structured to the wave by the digifax transition and exports it. It is used for restructuring a sort of control mechanism of the storage deepness that it does not work the wave distortion and it makes the best of the storage deepness according to the quantity of the random wave sampling point. It not only satisfies the request of the storage of the more shortwave but also the long wave.

The invention discloses a high-pulse-repetition-frequency ultra-short laser pulse system. A single-longitudinal-mode laser is taken as a light source. The high-pulse-repetition-frequency ultra-short laser pulse system comprises a dislocated clipping mechanism and a beam splitting-phase modulating-beam combining pulse compression mechanism, wherein the dislocated clipping mechanism is formed by connecting a first photoelectric switch and a second photoelectric switch in series; and the pulse compression mechanism comprises an optical fiber beam splitter, a random wave generator, a phase modulating device and an optical fiber beam combiner. The system is simple in structure, two photoelectric switches can be directly used for generating high-pulse-repetition-frequency laser pulses of shorter pulse widths, two or more paths of phase-modulated optical pulses can be used for generating shorter high-pulse-repetition-frequency laser pulse signals after beam combination, and the widths, repetition frequencies and pulse waveforms of pulses are optionally adjustable.

The invention discloses a fast simulation method for a non-stationary random process. The fast simulation method includes the steps: firstly, establishing the relationship between the multi-point non-stationary random process and a one-dimensional non-stationary random wave, namely, acquiring the two-dimensional evolutionary power spectrum density of a transformation random wave according to the evolutionary power spectrum and the coherence function of a given target random process; secondly, decoupling 2D EPSD by a proper orthogonal decomposition method; finally, simulating the transformation random wave by two-dimensional FFT (fast Fourier transform) to obtain the corresponding target non-stationary random process. Cholesky decomposition is omitted, decoupling time based on POD (proper orthogonal decomposition) is shortened, and the two-dimensional FFT technology is used, so that simulation efficiency is greatly improved. In addition, when parameters are properly selected, precision is still is high. In conclusion, the fast simulation method has the advantages of easiness in use and high precision and simulation efficiency, and can effectively solve the problem that the simulation efficiency of a spectral representation method is low when non-stationary random process simulation points are large.

The invention discloses a method for pushing plate to create random wave, which comprises the following steps: (1) establishing a numerical wave flume; (2) adding a moveable pushing plate with certain thickness to the wave creating end Xmin at the flume and adding porous medium to the end part as a wave silencing structure; (3) obtaining random wave parameters; (4) determining whether it is the first random wave; (5) generating random initial phase; (6) according to the obtained dum5 value, determining a P-M spectrum or a Jonswap spectrum; (7) calculating the wavelength L at this time;(8) calculating the Jonswap spectrum;(9) on the basis of the linear system theory, calculating a frequency responding function;(10) based on the above calculations of initial phase value, the spectrum function value, and the frequency responding function value and according to the superposition theory of linear wave, calculating the displacement speed of the pushing plate, and generating the random wave according to the speed of the pushing plate at which the pushing plate is controlled to move. According to the method of the invention, the end part is added by porous media to serve as a wave structure, which solves the problem that the wave creation water rises in size in a closed boundary closed boundary. With a closed boundary numerical wave flume, water exchange can be simulated. The method finds wide applications.

The invention discloses a multi-degree-of-freedom eccentric swing type wave power generation device and method. The multi-degree-of-freedom eccentric swing type wave power generation device comprisesan arc-shaped shell. An upper outer ring is mounted at the top of the arc-shaped shell, a top cover is mounted at the top of the upper outer ring, a lower base in the horizontal direction is mounted at the bottom of the arc-shaped shell, a gear frame is mounted on the lower base, and a generator, a driven shaft and a gear shaft are mounted on the gear frame in the vertical direction. An output shaft of the generator is connected with a bearing mounted on the lower base, and a generator gear capable of driving the generator to rotate is mounted on the output shaft of the generator. The arc-shaped shell of the power generation device is of a symmetrical structure, and the power generation device can capture wave energy of incoming waves in all directions, is not limited by wave directions, and is suitable for using in a random wave environment. According to the power generation method and the power generation device used by the same, gear commutation is adopted to convert the bidirectional swing of a swing arm into the unidirectional rotation of the generator without installing a plurality of generators, so that the structure is simplified, the size is reduced, the movement synchronization rate of different output ends is ensured, and the electrical power output is more stable.

The invention discloses a method for transmitting data based on random wave beam shaping, comprising the following steps: a base station terminal generates a beam shaping unitary matrix with constant amplitude for each element and random variable phase position; the base station terminal transmits a plurality of different training symbols to user equipment through the unitary matrix; the user equipment feeds back a received maximum value in a plurality of SINR corresponding to a launching beam and a corresponding number of the launching beam to a base station; and the base station selects the user equipment corresponding to the maximum SINR in the beam for different launching beams for data transmission. The method is applicable to arbitrary number of launching antennae, not only ensures the same amplitude for all the elements of a beam shaping matrix so as to significantly reduce the requirement on a dynamic range of a power amplifier and realize the random beam shaping technology with only one set of phase switcher as well, but also can obtain the same thuoughput as the prior random beam shaping system.

The invention provides an active absorption type plate-pushing wave generation device based on moment feedback, and the device comprises an industrial personal computer, a controller, a servo motor, a moment sensor, an absorption filter, and a push plate, wherein the industrial personal computer is connected with the controller, and is used for transmitting a position signal of a wave generator. The controller is connected with the servo motor, and drives the servo motor to rotate according to the received signal. The servo motor drives the push plate to move through a mechanical structure. The moment sensor is located in the servo motor, and is used for collecting the output torque of the motor in real time. One end of the absorption filter is connected with the moment sensor, and receives the collected real-time torque, and the other end of the absorption filter is connected with the controller, and enables a motion signal after feedback correction to be transmitted to the controller. The device is high in precision of the wave generation technology, and the impact on the device from an environment is small. The feedback signal is convenient to obtain. The wave generation technology can generate a long-time stable regular wave and random wave sequence, and improves the accuracy of wave model tests.

The invention provides a signal generator and a wavetable recombination method thereof. The signal generator comprises a CPU, a field programmable gate array (FPGA), an external waveform memory, a digital analog conversion chip and an analog circuit. The field programmable gate array is connected to the CPU through a CPU interface. The external waveform memory is connected with an external storage controller of the FPGA. The external waveform memory comprises a user wavetable storage module and a buffer wavetable storage module. The user wavetable storage module is used for storing a user wavetable. The FPGA comprises a work mode determination module which is in the CPU and is used for determining whether a work mode of a random wave is a pumping point mode or not, and a wavetable recombination module which is connected with the CPU interface and controls the external storage controller to draw a wavetable from the user wavetable storage module and outputs a stored wavetable. According to the signal generator and the wavetable recombination method, an output frequency scope and frequency precision of a large wavetable random wave are raised.

An apparatus used for simulating an ocean environment load comprises reaction frames and loading units of a length and width directions, an ocean conduit frame platform model, a computer system and a servo driver. The loading unit of the length direction applies a horizontal load along a model length direction, and the loading unit of the width direction applies a horizontal load along a model width direction. The loading units of the two directions comprise servo electric cylinders formed by servo motors and actuators, front end and rear end connection boards, front end and rear end spherical hinge assemblies and displacement and pressure sensors. The reaction frames are connected to a ground concrete foundation. An upper end is connected to a rear end connection plate of a loading device through welding so that a support effect is achieved. The computer system sets a load parameter and a PID adjusting parameter according to a requirement, emits an instruction to the servo driver and receives collected data. The apparatus can apply rule wave or random wave loads with different parameters on a model and possesses characteristics of shock resistance performance, a long service life and simple operation and maintenance.

The invention discloses a 100MHz high repetition frequency, 1ns narrow pulse width narrow line width laser mixing amplifying device and method. The 100MHz high repetition frequency, 1ns narrow pulse width narrow line width laser mixing amplifying device comprises a single-frequency continuous optical fiber laser device, a high-speed light intensity modulator, a super-high frequency random wave generator, an optical isolator, an optical fiber amplifier, a polarization isolator, a collimator, a coupling lens and an LD double-end-surface pump solid laser amplifier. The single-frequency continuous optical fiber laser device, the high-speed light intensity modulator, the super-high frequency random wave generator, the optical isolator, the optical fiber amplifier, the polarization isolator, the collimator and the coupling lens are sequentially connected; the coupling lens and a two-color coupling mirror on the LED double-end-surface solid laser amplifier are connected; the super-high frequency random wave generator is connected with the high-speed light intensity modulator. According to the 100MHz high repetition frequency, 1ns narrow pulse width narrow line width laser mixing amplifying device, a small-signal single-frequency optical fiber laser device can be modulated through the high-speed modulator; when high power is provided, the solid laser amplifier is used for amplifying, and therefore the problem that the amplifier is damaged under a high power condition cased by easily generated stimulated scattering and spontaneous amplification radiating effect is avoided.

The invention discloses a sea-crossing bridge dynamic response calculation method based on wind wave load combination. The sea-crossing bridge dynamic response calculation method comprises the following steps that 1, Establishing the coupling relationship between wind and wave and wind flow respectively; Step 2: Determining the wind, wave and flow parameters of different return periods, and obtainWind-wave-flow combination in a certain return period according to the coupling relationship of step 1.; Step 3: Determining the wind load point coordinates to generate a random wind field to obtainthe wind load; Step 4: Determining the wave flow point coordinates to generate a random wave flow field, and obtaining the wave load and the water flow load; 5: According to the wind-wave-flow combination obtained in step 2 and the load obtained in steps 3 and 4, obtaining the wind- wave-lfow load combination T; step 6: bringing the combination obtained in step 5 into the bridge across the sea toobtain dynamic response of the bridge. the invention fully considers the coupling relationship between the wind and the waves, and is more suitable for the actual situation, and is applied to the engineering design to reduce the engineering cost.