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49 results about "Latin square" patented technology

In combinatorics and in experimental design, a Latin square is an n × n array filled with n different symbols, each occurring exactly once in each row and exactly once in each column. The name "Latin square" was inspired by mathematical papers by Leonhard Euler (1707–1783), who used Latin characters as symbols, but any set of symbols can be used: in the above example, the alphabetic sequence A, B, C can be replaced by the integer sequence 1, 2, 3. Euler began the general theory of Latin squares.

Automobile hub lightweight design method

The invention discloses an automobile hub lightweight design method. The method comprises the steps of S1, establishing an automobile hub three-dimensional geometrical model and filling the spoke area of the geometrical model with materials; S2, establishing a hub topology optimization mathematical model and obtaining the optimal material distribution structure of a hub by means of topology optimization; S3, conducting secondary design and strength analysis in CAD software according to the hub structure subjected to topology optimization; S4, establishing an approximation model by means of the Latin square test sampling method and the response surface technology, and conducting size optimization on the hub subjected to secondary design by means of the evolution algorithm; S5, conducting strength verification on the optimized model. According to the method, conceptual design is conducted on the automobile hub firstly through topology optimization to obtain optimal material structure distribution of the automobile hub, then the approximation model is established by means of the Latin square testing method and the response surface technology with the strength of the hub as the restraint condition, detailed size optimization is conducted on the hub subjected to secondary design by means of the evolution algorithm, and then lightweight of the hub is realized.
Owner:DALIAN UNIV

Natural laminar flow nacelle appearance determination method and system

ActiveCN108009383AFavorable pressure gradientInhibition of flow towards TS wave growthGeometric CADSustainable transportationJet aeroplaneNacelle
The invention discloses a natural laminar flow nacelle appearance determination method and system. The method comprises the following steps of: parameterizing a section of a to-be-improved nacelle byadoption of a CST method, and obtaining a position of a transition of the natural laminar flow nacelle through a gamma-Re theta transition model; obtaining boundary conditions of an air inlet and an engine outlet; obtaining variable groups by adoption of a Latin square design method; obtaining corresponding nacelle resistance according to the variable groups; establishing a first Kriging responsesurface model; obtaining a variance of the nacelle resistance corresponding to the variable groups; establishing a second Kriging response surface model; determining a target function, and predictinga mean value and a variance of the nacelle resistance by utilizing the first Kriging response surface model and the second Kriging response surface model; obtaining a variable group which enables a function value the target function to be the minimum, so as to obtain an optimal variable group; determining an appearance of the natural laminar flow nacelle according to parameters in the optimal variable group. The method and system are capable of effectively improving the performance of appearances of laminar flow nacelles, decreasing the skin friction resistance of airplanes and improving the economic efficiency of the airplanes.
Owner:INST OF HIGH SPEED AERODYNAMICS OF CHINA AERODYNAMICS RES & DEV CENT

Color image encryption method based on Latin square scrambling

The invention relates to a color image encryption method based on Latin square scrambling. Plaintext keys r1, g1 and b1 are calculated through utilization of R, G and B components of a color plaintextimage, an initial value and a parameter obtained through calculation based on the keys are substituted into a chaotic system, and three groups of chaotic sequences are generated; the chaotic sequences for scrambling and diffusion are selected through utilization of a chaotic sequence selection mechanism based on the plaintext and digital arrangement; and a final ciphertext image is obtained through adoption of a block scrambling policy based on a Latin square and the chaotic sequences, and diffusion operation based on the plaintext and a scrambled image. The encryption method is closely related to the plaintext, so the plaintext attack resistance is improved. The employed chaotic system is an improved chaotic system, a chaotic characteristic is good, the randomness is high and a key spaceis great, so a security level is further improved. A simulation result and safety analysis show that according to the encryption provided by the invention, an image complete encryption demand can besatisfied, the encryption efficiency is high, and the robustness is high.
Owner:HENAN UNIVERSITY

Generalized perception model under limited spectral resources and distributed Q learning access method

The invention discloses a generalized perception model under limited spectral resources and a distributed Q learning access method. According to the model, a channel perception mechanism based on a zero-added latin square matrix is proposed by considering limitation of spectrum resources and dynamism of network environment and aiming at the problem of multiple time-slot channel perception sequenceoptimization. The method includes the following steps that firstly, a game model is constructed, and participants are all cognitive users in a network; based on the generalized perception model, eachuser randomly selects a channel perception sequence strategy from the corresponding zero-added latin square matrix and conducts perception; each active user calculates a current state return value and conducts Q-value update and probability update for the next time slot on the basis of the current state return value; the cognitive users conduct time-slot perception circularly until channel perception sequence strategies of all the cognitive users are converged. By adopting the model and the method, multiple time-slot channel perception sequence conflict is effectively reduced under the limited spectral resources, and handling capacity of the system cognitive users is improved.
Owner:ARMY ENG UNIV OF PLA

Method and system for a turbo trellis coded modulation scheme for communication systems

InactiveUS20060078062A1Improvement in achievable coding gainImprovement in the achievable coding gainData representation error detection/correctionError correction/detection using trellis codingConvolutional codeBinary phase shift keying bpsk
Method and System for evaluating a turbo-coding scheme suitable for VDSL2 systems. The scheme is a Turbo-Trellis Coded Modulation TTCM that makes use of a Parallel Concatenated Convolutional Code (PCCC) including an inner Latin square/rectangular matrix of Random sequence pattern Interleaver (LRI) of approximately 2044 bits. In the presence of the outer Reed Solomon Code but without an outer interleaver (fast mode), the method and system provides 7.1 dB of average net coding gain, i.e., 2.6 dB of coding gain improvement relative to the standard 16 states 4-dimensional (4-D) trellis code used in current ADSL2 systems. The substantial coding gain achieved through the method and system, leads to an increase in the VDSL2 rate by 38% at 6 kft against local exchange carriers, such as ILEC (SBC) conditions with approximately 1.5 ms of latency. By encoding only two bits per tone (i.e., 1 bit per dimension), the turbo code implementation complexity is kept reasonable. Finally, the coded modulation scheme supports very small constellations, allowing transmitting spectral efficiency as low as 0.5 bit/sec/Hz over Binary Phase Shift Keying (BPSK) constellations at a signal-to-noise-ration (SNR) very close to the Shannon bound.
Owner:IKANOS COMMUNICATIONS

Multi-path communication method based on secret sharing in vehicle-mounted ad hoc network environment

The invention relates to a multi-path communication method based on secret sharing in a vehicle-mounted ad hoc network environment, which comprises the following steps: finding a plurality of disjointpaths between a starting node and a target node by utilizing a Latin square matrix, and dividing a symmetric encryption key into a plurality of sub-keys by utilizing secret sharing. Meanwhile, the encrypted message is also divided into a plurality of parts, an equivalent commitment is generated for each sub-key to support fault tolerance, and meanwhile, a current timestamp is selected to resist areplay attack, the encrypted sub-key, the ciphertext and the commitment are jointly transmitted to the target node through each path,the target node reconstructs a key by using the sub-key, and decrypts the ciphertext by using the key to obtain an original message. According to the communication method, the network load is greatly reduced, the information transmission efficiency is improved, andmeanwhile the communication method has the advantages of being good in stability and not prone to being attacked or stealing private data. The communication method also has high fault tolerance, andcan provide normal service even when unstable factors such as network congestion, flow limitation and node equipment damage occur.
Owner:NANJING UNIV OF INFORMATION SCI & TECH

Building instantaneous cold load prediction method based on Monte Carlo method applying Latin hypercube sampling

The invention relates to a building instantaneous cold load prediction method based on a Monte Carlo method using Latin hypercube sampling. The method comprises: using a Monte Carlo simulation methodto calculate a building cold load, and using the Latin hypercube sampling method to perform random sampling of the Monte Carlo simulation method; the Monte Carlo simulation method being a numerical calculation method guided by a probability statistics theory, performing random sampling on all uncertain parameters forming the building cooling load, recombining samples of all the uncertain parameters, and obtaining probability distribution of the building instantaneous cooling load after multiple times of Monte Carlo simulation. In the statistical sampling process, the Latin hypercube is the popularization of a Latin square matrix in multiple dimensions, each hyperplane perpendicular to the axis contains at most one sample, and therefore the Monte Carlo simulation frequency is reduced whilethe randomness of the samples is guaranteed. According to the method, the building instantaneous cooling load can be effectively calculated and predicted, and a reference basis is provided for installation and model selection of the building air conditioning system and operation optimization of the air conditioning system.
Owner:HUADIAN ELECTRIC POWER SCI INST CO LTD

Latin square-based chaotic image encryption method

The invention provides a Latin square-based chaotic image encryption method, which comprises the following steps of: generating a key by using an original image matrix, and inputting the key into a hyperchaotic Lorenz system to obtain a chaotic sequence; intercepting the chaotic sequence, converting the chaotic sequence into a matrix, and scrambling an original image matrix; intercepting the chaotic sequence to generate a Latin square matrix as a lookup table; intercepting the chaotic sequence and forming an index matrix, and selecting elements from corresponding coordinates in the lookup table by using the index matrix for replacement to obtain a pixel replacement matrix; and intercepting the chaotic sequence and generating a Latin square matrix, forming a bit matrix by using bit planes of the pixel replacement matrix, performing bit scrambling on the bit matrix by using the Latin square matrix, combining the bit matrix and the Latin square matrix into a bit plane matrix, and converting the bit plane matrix into a decimal system to obtain a ciphertext image. Latin square matrices used in the method are all generated by chaotic sequences, so that the complexity is enhanced, and the safety is improved; the randomness and the sensitivity are effectively improved, differential attacks can be effectively resisted, the decoding difficulty is increased, and the method is suitable for practical application.
Owner:ZHENGZHOU UNIVERSITY OF LIGHT INDUSTRY

Method and apparatus for determining transmission time-frequency resources of traffic data

The invention provides a method of determining transmission time-frequency resources of traffic data in a wireless communication network. The network device determines a time-domain transmission pattern Pi, j of the traffic data from a time-domain transmission pattern set PI, J; determines a frequency hopping pattern of the traffic data based on a frequency hopping matrix and a first rule, wherein the frequency hopping matrix is constructed by one or more Latin squares, a number of rows of the frequency hopping matrix is equal to a number of sub-bands in a frequency hopping bandwidth, each element in a row of the frequency hopping matrix successively represents a frequency hopping order of the complement transmission patterns Pi, j and Pi, j′, a number of columns of the frequency hopping matrix is equal to a number of transmissions of the traffic data, and the first rule is Pi, j and Pi, j′ are assigned with a same channel within a sub-band and a value of j is a part of J or all of J, the complement transmission patterns Pi, j and Pi, j′ in the transmission pattern subset Pi, J are assigned with a same channel within a sub-band and use a same sub-band for their first transmission, the non-complement transmission patterns Pi, j and Pi, k in the transmission pattern subset Pi, J have a same relative location in each sub-band and the non-complement transmission pattern subsets Pi, J and Ps, J are assigned with the different channels within a sub-band; and sends the traffic data according to the time-domain transmission pattern Pi, j and the frequency hopping pattern.
Owner:ALCATEL LUCENT SAS
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