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119results about How to "Avoid cumbersome calculations" patented technology

HTML webpage tamper detection and positioning method

The invention provides an HTML webpage tamper detection and positioning method, including the following processes: (1) watermark pre-embedding process, the numerical values of characters on corresponding positions in each line and each row in the original HTML webpage source codes are respectively extracted so as to obtain corresponding one-dimensional arrays, and the generated one-dimensional arrays are respectively converted into two-dimensional matrixes; a line digital watermark and a row digital watermark are generated, authentication codes in the line digital watermark and the row digital watermark are in two-position tandem connection so as to obtain a webpage digital watermark; the webpage digital watermark is embedded in the original HTML webpage source codes in advance; (2) tamper detection and positioning process, firstly, the extraction and the recovery of the webpage digital watermark are carried out; secondly, the webpage digital watermark which is embedded in advance is compared with a new webpage digital watermark, and the complete matching of the two webpage digital watermarks can indicate that the webpage source codes are not tampered, or the lines and the rows with different authentication codes in the two webpage digital watermarks are defined to be tampered in the premise that the two webpage digital watermarks are not completely matched with each other.
Owner:HUAZHONG NORMAL UNIV

Circular array phase position interferometer broadband instantaneous direction finding method based on table lookup method

The invention belongs to the technical field of communication radars, and provides a circular array phase position interferometer broadband instantaneous direction finding method based on a table lookup method. The circular array phase position interferometer broadband instantaneous direction finding method based on the table lookup method specifically includes the following steps: building a lookup table, traversing all phase differences in a range of (-pi, pi] at an interval of 2pi / (2L-1), and constructing a phase difference combination; performing ambiguity resolution calculation on all the phase differences so as to obtain a phase ambiguity number; constructing tabular value, and building another lookup table; obtaining measuring value of the phase differences through phase demodulation system measurement, performing table lookup and calculation so as to obtain corresponding tabular value and resolving the corresponding tabular value into a corresponding ambiguity number, and calculating a true phase difference; calculating a pitch angle and an azimuth angle of a wave incoming direction according to the wavelength output by a frequency system and the true phase difference. The circular array phase position interferometer broadband instantaneous direction finding method based on the table lookup method uses the table lookup method to solve ambiguity, avoids tedious calculation of formula ambiguity resolution, greatly shortens direction finding time, can shorten the direction finding time from ten milliseconds into hundred nanoseconds, and adapts to real time application.
Owner:NAT UNIV OF DEFENSE TECH

Method for designing elliptic cylindrical surface transverse gradient coil based on spatial alternation

The invention discloses a method for designing an elliptic cylindrical surface transverse gradient coil based on spatial alternation. The method is characterized by comprising the steps that firstly, two shafts of the elliptic cylindrical surface where the gradient coil is located are defined to be in the direction x and the direction y, the shaft length of the elliptic cylindrical surface where the gradient coil is located in the direction x is 2a, the shaft length in the direction y is 2b, the wiring length in the axial direction is 2L, the strength of the gradient field is G, and the linearity is E; secondly, spatial alternation is utilized for converting the elliptic cylindrical surface into a cylindrical face, and the current density basis function and the expression are constructed under the cylindrical face; thirdly, a functional construction related to the current density is built, and the coefficient of the current density expression is obtained by solving the functional extreme value; fourthly, the solved coefficient of the current density expression is utilized for solving distribution of current density in the space, and the wiring shape of the gradient coil is obtained. The complex calculation of gradient coil designed through the network discrete method is avoided, and the high efficiency and precision are obtained.
Owner:HOHAI UNIV

Printing system of holographic stereogram and with abnormal-shaped mask plate

The invention belongs to the technical field of holographic printing and three-dimensional display and particularly relates to a printing system of a holographic stereogram and with an abnormal-shaped mask plate. The printing system is formed by a laser light source, a beam splitter, an expanded beam collimation system, a spatial light modulator, a computer, a total reflection lens, a focusing lens, hologram recording materials, the abnormal-shaped mask plate, a target object and a CCD (Charge Coupled Device) camera. A transformation parallax image of the target object is obtained through the CCD camera and the computer and loaded into the spatial light modulator, a light beam which is emitted from the laser light source is modulated, interference is produced between the modulated light beam and the other laser beam which is reflected by the beam splitter, the two light beams penetrate the abnormal-shaped mask plate to be exposed and recorded on the holographic recording materials, and accordingly printout of the holographic stereogram of the target object is achieved. The printing system of the holographic stereogram and with the abnormal-shaped mask plate has the advantages of being capable of effectively improving the printout speed of the hologram, solving the problem of frequency spectrum leakage of the traditional hard edge aperture printing of the holographic stereogram due to the abnormal-shaped mask plate and improving the representing quality of the holographic stereogram.
Owner:ACADEMY OF ARMORED FORCES ENG PLA

Small gear rough cutting method for spiral bevel gear

The invention discloses a small gear rough cutting method for a spiral bevel gear. The method comprises the steps that the concave face and the convex face of a small gear are positioned through small gear finishing bevel gear cutter parameters, machine tool adjusting parameters and midpoint checking sizes to obtain a small gear finish cutting gear socket, and coordinates and normal vectors of key points of the two tooth faces are calculated; initial rough cutting machine tool adjusting parameters are given, an equation of the tooth faces on the two sides of the small gear rough cutting gear socket is built, and coordinates of the corresponding key points are obtained; after the midpoint of the small gear rough cutting hear socket is rotated to the midpoint of the small gear finish cutting gear socket, the key points corresponding to the two gear sockets are connected and projected on the normal line of the key points of the finish cutting gear socket to obtain finish cutting allowance; the square root of the difference between the optimized finish cutting allowance and the preset finish cutting allowance is made to be the minimum by optimizing roughing bevel gear cutter parameters or machine tool adjusting parameters. According to the method, the roughing bevel gear cutter specifications can be reduced, the roughing bevel gear cutter and cutter tooth utilization rate is increased, it is ensured that the finish cutting allowance of the tooth faces on the two sides is uniform as much as possible, the follow-up finishing frequency is lowered, and the machining efficiency of the bevel gear is improved.
Owner:CHANGAN UNIV

Global optimization control method of ground source heat pump

ActiveCN109186127ASignificant energy saving effect of water pumpImprove developmentHeat pumpsRefrigeration safety arrangementPhysical modelEvaporator
The invention discloses a global optimization control method of a ground source heat pump. Physical models of a ground source heat pump unit, a ground heat exchanger and a water pump are established and analyzed, an optimization algorithm is used for optimizing user side flow rate and ground side flow rate, and the optimized value is used as a set value to a bottom layer closed loop control to enable a ground source heat pump system to operate at an optimal state point. According to the global optimization control method of the ground source heat pump, a brand-new global control strategy of the ground source heat pump system is determined by modeling analysis of a compressor, an evaporator and a condenser of the ground source heat pump system and combining a particle swarm optimization algorithm, the influence of external interference and the control strategy on the system are fully considered, corresponding correction compensation measures are set, and strong engineering practical significance is achieved; in the actual operation process, the energy is saved by 14% compared with a constant flow operation strategy, and energy is saved by 6.7% compared with a traditional five-degreetemperature difference control strategy, and the global optimization control method of the ground source heat pump has important significance for saving the operation energy consumption of the groundsource heat pump system.
Owner:飞卓博瑞流体控制技术(上海)有限公司

Satellite passive positioning method based on GPS broadcast data

The invention provides a satellite passive positioning method based on GPS broadcast data. The method comprises: acquiring measuring data of a satellite; according to the measuring data, calculating a conversion matrix M from an earth-fixed coordinate system to a satellite local system; selecting an earth ellipsoidal model and obtaining corresponding earth geometrical parameters and an earth ellipsoidal surface equation; and according to the conversion matrix M, solving an object position equation, and solving object position coordinates by simultaneously solving the earth ellipsoidal surface equation. The measuring data comprises the GPS broadcast data including a satellite real-time position P<se><-> and a speed V<se><->, object measurement angles beta<x> and beta<y> and attitude angle data, i.e., a pitch angle phi, a yaw angle yaw angle gamma and a roll angle theta, wherein the GPS broadcast data is obtained through a satellite data bus, the beta<x> and the beta<y> are obtained through a load subsystem, and the attitude angle data is obtained through an attitude orbit control subsystem. According to the invention, the high-precision GPS broadcast data is taken as a system input quality, such that the precision of each parameter during a calculation process is ensured, accordingly, the precision of a positioning result is ensured, at the same time, an offline processing process is unnecessary, and the satellite autonomous calculating capability is enhanced.
Owner:SHANGHAI SATELLITE ENG INST

Filter for BDS (beidou navigation satellite system) and SINS (strapdown inertial navigation systems) navigation and positioning system and filtering method

The invention discloses a filter for a BDS (beidou navigation satellite system) and SINS (strapdown inertial navigation systems) navigation and positioning system and a filtering method, and relates to the technical field of navigation and positioning. The method comprises the steps of building a first Gaussian mixture model formed by a plurality of Gaussian components according to the system state noise distribution condition and the posterior probability density of the navigation output result at the former moment; performing time updating on each Gaussian component in the first Gaussian mixture model according to the unscented kalman filtering, and obtaining the time predicating result corresponding to each Gaussian component; building a second Gaussian mixture model formed by a plurality of Gaussian components according to the measuring noise at the current moment; performing measurement updating according to each time predicating result according to the second Gaussian mixture model to obtain a plurality of measurement updating results; merging the plurality of measurement results to generate the navigation output result of the current moment. After the filter is applied to the BDS / SINS vehicle-mounted combined navigation system, the navigation parameter precision is ensured; meanwhile, the calculation rate is high; the work real-time performance is better.
Owner:CHONGQING WATER RESOURCES & ELECTRIC ENG COLLEGE

Method for comprehensively evaluating the combustible dust explosion hazard level by utilizing multi-element dust explosion parameters

InactiveCN109389256ARapid identification of explosion hazardsThe evaluation method is simpleResourcesLower limitPressure rise
The invention discloses a method for comprehensively evaluating the combustible dust explosion hazard level by utilizing multi-element dust explosion parameters. The method adopts fuzzy mathematics theory and analytic hierarchy process (AHP) in the system evaluation method, Using representative conventional explosives, According to the minimum ignition energy of dust cloud, the minimum ignition temperature of dust cloud, the minimum ignition temperature of dust layer, the lower limit of explosion, the maximum explosion pressure, the maximum explosion pressure rise rate and the characteristic parameters of explosion index, the membership function is established, and the evaluation model is established to evaluate the explosion hazard of different dust. The comprehensive evaluation method ofthe combustible dust explosion hazard grade established by the invention is simple, Easy to popularize, avoid tedious calculation and test, combine the existing data to obtain the corresponding comprehensive index value, easy to form a common evaluation standard, the result is intuitive, rapid identification of combustible dust dust explosion hazards, can provide guidance for the enterprise design safety production process.
Owner:NANJING UNIV OF SCI & TECH

A method for calculating the ultimate bearing capacity of a strip foundation under an inclined load

A method for calculating the ultimate bearing capacity of a strip foundation under an inclined load is disclosed. By constructing a failure model of a multi-rigid-block foundation under an inclined load, the formula for calculating the ultimate bearing capacity of strip foundation under inclined load is established, and the problem of solving the ultimate bearing capacity of strip foundation is equivalent to a multi-dimensional function extreme value problem with nonlinear constraints. The method takes the advantage of the improved radial motion algorithm to solve the extremum problem of multidimensional functions; the failure slip line of foundation is searched for and the corresponding ultimate bearing capacity of foundation is calculated. Through continuous comparison and progress, thefailure slip line in the domain that makes the minimum bearing capacity of foundation is found, and the corresponding minimum bearing capacity is the ultimate bearing capacity of foundation. Comparedwith the prior art, the invention avoids the tedious calculation of the traditional theoretical method and the limitation of the calculation precision, can conveniently and quickly find out the foundation failure slip surface under the action of the inclined load, and greatly improves the work efficiency.
Owner:CENT SOUTH UNIV
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