67results about How to "Reduce calculation precision" patented technology

The invention discloses an electrical-information-acquisition-system-based theoretical line loss estimation method for a distribution network, and aims to overcome the shortcomings of great errors of the conventional theoretical line loss estimation method for the distribution network, difficulty in accurate analysis on the characteristics of load fluctuation, unbalance, harmonic distortion, parameter variation and the like of the distribution network, and the like. By the method, each loss influencing factor of a medium and low voltage distribution network can be scientifically, perfectly and comprehensively reflected; and compared with a 'root-mean-square current method', an 'average current method', a 'maximum current method', an 'equivalent resistance method' and the like for estimating line loss only according to the single line diagram of the distribution network, typical day 24 hours, asynchronous current recording data and the like in DL686-1999 guide of calculation of grid energy loss, the invention has more accurate algorithms, parameters, load data and the like for the theoretical line loss, and provides a novel concept and a novel method for the loss analysis and energy efficiency evaluation of the distribution network.

The invention relates to a cardinal number estimating method and a cardinal number estimating device under a multi-section query condition of big data. The cardinal number estimating method comprises the following steps of dividing the big data into a plurality of sections in advance according to numerical attributes; establishing a tree-shaped index structure, and utilizing each section as a node of the tree-shaped index structure; acquiring a data source to be written in the tree-shaped index structure, and reversely indexing the data source which supports the section query condition; writing the data source which is reversely indexed into the nodes of the tree-shaped index structure, and respectively writing corresponding portions of the data source into data files and a cardinal number estimator; and querying the nodes meeting the section query condition in the tree-shaped index structure according to the section query condition to obtain the cardinal number estimator in the nodes, and logically processing the cardinal number estimator to obtain cardinal number estimated values. The cardinal number counting efficiency is improved by reducing data calculating precision; the query efficiency is high under the optional multi-section query condition; and the online index data updating efficiency is improved by using a big data incremental updating technology.

The invention belongs to the technical field of channel prediction, and discloses a RBF (Radial basis function, radial basis function) neural network channel prediction method based on phase space reconstruction. The method comprises the following steps: obtaining a channel coefficient, and establishing a sample training data set; solving a phase space reconstruction parameter; performing phase space reconstruction on the sample training data set; selecting a neighbor domain node in a reconstruction phase space; training a RBF neural network by using the neighbor domain node; performing prediction by using the trained neural network; and converting a prediction result into an original space to obtain a prediction value. According to the RBF neural network channel prediction method provided by the invention, the prediction time is relatively long, and meanwhile the calculation complexity of the RBF neural network is reduced; and the RBF neural network channel prediction method can be applied to the channel prediction of an LTE uplink.

The invention belongs to the five-axis numerical control machine tool machining field, and provides a semi-analysis modeling method of a contact area between a ball-end milling cutter and a guide vane. The semi-analysis modeling method of a contact area between a ball-end milling cutter and a guide vane includes the following steps: performing cutter path programming, and setting numerical control machining parameters; establishing a workpiece coordinate system, and acquiring the parameter equations of the design surface and the machining surface of the vane, and the movement track equation of the ball center of the milling cutter; determining the cutter contact point and the cutter location point during the machining process, taking the cutter contact point and the cutter location point as the origin to respectively establish a three dimensional rectangular coordinate system; converting solving problems of No.1-No.4 boundary curves of the contact area into projection equation solving problems of the curves in an XL-YL two dimensional coordinate system, and respectively solving the projection equations of the No.1-No.4 boundary curves; and obtaining the intersection points of the No.1-No.4 boundary curves, by mutually making a simultaneous system of equations, and obtaining the projection of the contact area. The semi-analysis modeling method of a contact area between a ball-end milling cutter and a guide vane can solve the problem of performing analysis modeling of the contact area during the process of processing a straight-vane-body vane molded in a vane grid by means of a ball-end milling cutter on a five-axis numerical control machine tool.

The invention discloses a non-structural mass trimming method for an airplane in a steady overload state. By introducing increment of a non-structural mass unit, the aerodynamic load and the inertial load of the airplane are trimmed, so that a result obtained by analyzing a finite element model without displacement constraint is more reasonable than a result obtained by a displacement constraint method and an inertia relief method. According to the non-structural mass trimming method, a poly-condensed load array is obtained through a poly-condensation technology so as to accurately obtain a non-balance system of force of an airplane structure relative to a reference point; and a trimming load is further obtained by airplane overload, and the trimming load is equivalently converted into an increment attribute of a trimmed non-structural mass unit. According to the method, mass load increments are transferred to structural units by utilizing connection of RBE3 rigid units, namely, an inertial load of the trimmed mass unit is transferred to a force-bearing point of a structural model of an oil tank, a warehouse or an equipment compartment so as to accurately obtain stress characteristics of the airplane structure. The non-structural mass trimming method has important application values and significances for improving the design accuracy of the airplane structure.

An apparatus able to regulate a raw material concentration, in a mixed gas of carrier gas and raw material gas, accurately and stably to supply the mixed gas to a process chamber, with a flow rate controlled highly accurately, thereby detecting a vapor concentration of the raw material gas in the mixed gas easily and highly accurately and displaying the concentration in real time without using an expensive concentration meter, etc.

Determination values are obtained by calculating values for each partial model of a complete model base at each unit time, and by integrating absolute values of change amounts of the values and absolute value of change amount of a product of at least two values, according to the engine acceleration pattern. A set of the determination values including a specific determination value of a specific partial model having the most influence on a specific value calculated using the model base is selected, wherein the specific determination value is the largest among the determination values of all the partial models. A higher priority is assigned to a partial model with a higher determination value. The model base is determined by omitting a partial model from the complete model base in order of ascending priority until a desired processing load of calculating the specific value is obtained.

A method and apparatus for coding an image includes calculation of motion vectors of vertices of a patch in an image being encoded and transmitting information of horizontal and vertical components of the motion vectors of the vertices and information specifying that values of the horizontal and vertical components of a motion vector for each pixel in the patch are integral multiples of 1/d of a distance between adjacent pixels, where d is an integer not less than 2.

The invention provides a short-circuit current analysis method and a device of a regional power grid. The method comprises the steps of regionalizing a power grid system: dividing a region with a short-circuit current level to be analyzed and calculated into a study area, dividing a region directly communicated with the study area into a boundary area, and dividing a region except the study area and the boundary area into an external area, performing equivalent simplification on the boundary area and the external area to form an equivalent boundary area, obtaining an equivalent power grid system consisting of the study area and the equivalent boundary area, and analyzing and calculating the short-circuit current level of the study area according to the equivalent power grid system. The method and the device solve the technical problems that the calculation accuracy of short-circuit current is difficult to guarantee in the prior art, and the data size during short-circuit current analysis is large, and achieves the technical effects of reducing the data size and calculation load during the short-circuit current analysis on the basis of ensuring the calculation accuracy of the short-circuit current.

The invention discloses a rectangular opening sound transmission rate and sound transmission loss computing method. The method comprises, firstly, defining a rectangular-opening coordinate system, and establishing force balance formulas of both cross sections of the opening and the sound transmission matrixes at both ends of the opening; secondly, utilizing the properties of sound radiating impedance of vibration of air layers at both ends of the opening to achieve computation of the sound transmission rate of a rectangular opening single-level mode under the condition of parallel sound wave incidence; thirdly, superpositioning the sound transmission rate of every level of mode to obtain the sound transmission rate of the rectangular opening; fourthly, integrating incident angles to obtain the sound transmission rate of the rectangular opening under the condition of scattered sound field incidence; lastly, calculating the sound transmission losses of the rectangular opening under the condition of the scattered sound field incidence through a relation between sound transmission losses and sound transmission rates. The rectangular opening sound transmission rate and sound transmission loss computing method can be used for computing the sound transmission rates or the sound transmission losses of one or more certain levels as well as computing total sound transmission rates or total sound transmission losses, thereby greatly improving the computing flexibility, and meanwhile, by omitting the influence of the very small sound radiating impedance of both a part of real parts and a part of imaginary parts, greatly improves the calculating speed.

The invention provides a brake glide quantity soft measuring method and a measuring device. According to the invention, at the weight hanging part of a crane, a data acquisition is arranged to acquire the acceleration velocity data and the angular velocity data of the weight hanging system, and transmits the data to a host computer where the data are calculated according to a non-linear dynamic differential equation for the weight hanging system built on the Lagrangian equation to obtain the brake glide quantity of the crane. Compared with the currently available system, all the measuring method needs to do is introduce a data acquisition device at the weight hanging part of the crane, free of the mechanical and circuit modifications to the crane loads and the brake controller. With the method and the device, it is possible to automatically measure the brake glide quantity of a crane, and the measuring accuracy is increased, ensuring the safe operations of the crane. In addition, the power consumption of the measuring system is planned, and the repetitive battery replacement becomes unnecessary; and at the same time, the wireless manner can be selected for data transmission, making the transmission not limited to distances. Therefore, with the method and the device, it is possible to estimate the brake performances of the crane in real time.

The invention provides a PCMA signal single-channel blind separation method based on an improved particle filter and belongs to the technical field of signal processing. The method is characterized by carrying out framing processing on a received single PCMA signal, determining parameter value range and distribution and initializing particles; carrying out updating according to a significance sampling function and a particle trajectory before the current time to obtain new particles; calculating particle importance weight values and setting a threshold value to discard particles, which contribute little to posteriori distribution, so that calculation is simplified by dynamically adjusting the total number of the particles; after obtaining parameter estimation values of two paths of uplink signals by utilizing a linear minimum mean square error criterion, designing a parameter-known signal separation method, and in the recursive calculation process of a likelihood function, discarding trajectories, the quality of which is poor, to further reduce calculation amount; and finally, obtaining symbol sequence estimation values of the two paths of uplink signals by utilizing a maximum likelihood criterion. Compared with the original algorithm, which adopts a state exhaustive method, the method can obviously reduce the calculation amount; and the method discards the poor-quality particles, so that computation accuracy required by real-time realization of the algorithm is reduced.

The invention discloses a method for obtaining a sound transfer rate and a sound transmission loss of a circular opening. The method is characterized by firstly defining a coordinate system of the circular opening, establishing force balances at cross sections of two sides of the opening and sound transfer matrixes at two ends of the opening, and calculating the sound transfer rate of a single-step mode state of the circular opening under parallel sound wave incident conditions by using properties of sound radiation impedance of air layer vibration at the two ends of the opening, superimposing sound transfer rates of different step mode states to obtain the sound transfer rate of the circular opening, integrating an angle of incidence to obtain the sound transfer rate of the circular opening under incident conditions of a scattering sound field, finally obtaining the sound transfer loss of the circular opening under the incident conditions of the scattering sound field through a relation of the sound transmission loss and the sound transfer rate. According to the invention, the sound transfer rates or the sound transfer losses of a certain step or multiple steps can be respectively calculated, and the total sound transfer rate or sound transmission loss can be further calculated to greatly improve the calculation flexibility. Influences of the sound radiation impedance of a real part and an imaginary part which are both small are partly ignored to greatly improve the computing speed.

The embodiment of the invention discloses a perpendicularity measuring method and device. The perpendicularity measuring method comprises: providing an optical autocollimator and a plane mirror; arranging the plane mirror on an objective table, reflecting a collimated beam by the plane mirror to form a light spot, and recording an initial imaging position of the light spot; enabling a base and a mirror frame to be in a screw joint relationship, arranging the base and the mirror frame on the objective table, and arranging the plane mirror on the mirror frame; rotating the mirror frame at leastthree times and recording a measurement imaging position of the light spot after rotation each time; according to the measurement imaging positions, acquiring a virtual imaging position reflected by the surface of the base; and calculating the perpendicularity of the respective thread axes of the base and the mirror frame and a bearing surface according to the e initial imaging position, the measurement imaging positions, the virtual imaging position, and a conversion relationship between a unit distance and a plane inclination angle on a scale dividing plate. According to the invention, the perpendicularity of the respective thread axes of the base and the mirror frame and the bearing surface can be measured and calculated simultaneously, so that the measurement efficiency of the perpendicularity is improved; and the calculation accuracy of the perpendicularity is ensured.

The invention relates to a method for solving dry flue gas quantity generated by fuel combustion, which is characterized in that theoretical dry flue gas quantity is directly solved by adopting fuel components, and the actual dry flue gas quantity is obtained by solving the theoretical dry flue gas quantity in combination with flue gas oxygen content. According to the method for solving the dry flue gas quantity generated by fuel combustion, the actual dry flue gas quantity data can be obtained only by inputting fuel components and flue gas oxygen content data, the solving precision can be guaranteed, the calculation process can be simplified, and the method is suitable for all fuels and has important practical significance.

The invention discloses a multi-energy system operation stability calculation method based on big data and belongs to the technical field of multi-energy system operation stability. According to the method, an electricity-heat-gas joint optimization scheduling model is established; a big data grading excitation function is used. The grading state of a multi-energy system is evaluated, element coefficients of various calculated quantities are unified, the measurement time interval is shortened to improve the calculation precision, the calculation process is simplified, the purpose of judging the reliability of a grading attribute operator is achieved, and the stability calculation of the multi-energy system under the support of a big data technology is completed. Coordinated operation of various forms of energy is achieved, and the energy use efficiency is improved.

The accuracy or computation speed of mechanical analysis of a golf ball using the finite element method is increased. In the mechanical analysis, a model representing the golf ball is prepared on a computer, and computation is made by the finite element method using elements and nodes. At this time, the elements are made solid elements of hexahedron, the aspect ratio of the shape of each element is set so as to be not lower than 1.0 and not substantially higher than 6.5, and nodes are provided on the sides and at the vertexes of the hexahedron of element.

The invention discloses a time slice processing method based on a trumpet, and the method can enable the length of a time slice to be similar to the trumpet according to the definition of a user, enables the length of the time slice closer to the current time to be shorter, and enables the length of the time slice longer than the current time to be longer. The trumpet-based time slice processing method is mainly divided into four parts: definition of trumpet-shaped time slices, creation of the trumpet-shaped time slices, management of the trumpet-shaped time slices and query of the trumpet-shaped time slices. According to the trumpet-shaped time slicing method, data with a larger time span can be reserved, a large amount of storage space is saved, index query delay under the large time span is further reduced, and query results can still be returned within millisecond-level delay.