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91 results about "Minimum entropy" patented technology

Travel time index entropy traffic circulation evaluation method

The invention discloses a travel time index entropy traffic circulation evaluation method which comprises the following steps of a, calculating the free stream speed of each road section in a road network according to historical speed data provided by road network vehicle detection equipment, b, calculating the travel time index of each road section, c, calculating cut-off positions of the travel time indexes according to a quantile method or road capacity, d, calculating discrete probability distribution of the travel time indexes of a probe vehicle, e, calculating the entropy of the travel time indexes, f, calculating the highest possible value of the entropy as the upper limit of a dynamic range through the maximum entropy theorem, g, using the minimum entropy value Hmin of the travel time indexes as the lower limit of the dynamic range of the entropy of the travel time indexes, and h, carrying out normalization processing between the upper limit and the lower limit of the dynamic range of the entropy to obtain a road network traffic circulation evaluation value. The travel time index entropy traffic circulation evaluation method is a scientific characterization method of traffic circulation states, and measurement of traffic jam severity degree is achieved from the aspects of system confusion and randomness and uncertainty of travel time.
Owner:北京交通发展研究院

Intelligent fault diagnosis method based on rough Bayesian network classifier

InactiveCN102879677AOvercome rigidityOvercoming the Weakness of Critical MisjudgmentElectrical testingInference methodsCurse of dimensionalityMinimum entropy
The invention provides an intelligent fault diagnosis method based on a rough Bayesian network classifier, which comprises the following steps: using standard fault feature data as a fault diagnosis condition attribute set, using a standard fault mode as a fault diagnosis decision attribute set, and adopting a rough set principle to construct an original fault diagnosis information table T1; adopting the minimum entropy method to carry out discrete processing on various continuous fault diagnosis condition attribute values in the T1, so as to form a discretization fault diagnosis information table T2; using a rough set discernable matrix and a nuclear theory to carry out attribute reduction and optimal feature selection on the T2, so as to form a reduction fault diagnosis information table T3; and using the T3 to establish the Bayesian network classifier, so as to realize efficient and quick intelligent fault diagnosis. The intelligent fault diagnosis method avoids the 'curse of dimensionality' problem existed in a Bayesian network diagnostic method, overcomes weaknesses of rigid reasoning and critical misjudgment in a rough set diagnostic method, and greatly improves the efficiency and accuracy of fault diagnosis.
Owner:NORTHWESTERN POLYTECHNICAL UNIV

Measuring method of bi-static forward-looking and squinting synthetic aperture radar Doppler center frequency

The invention belongs to a measuring method of synthetic aperture radar (SAR) non-fuzzy Doppler center frequency, comprising: compressing range direction pulse; obtaining initial slope; converting a frequency domain and a time domain; obtaining the waveform entropy of a sequence; determining the minimum waveform entropy; and determining the non-fuzzy Doppler center frequency. The invention utilizes the geometrical characteristics of the synthetic aperture radar echo on range time and azimuth time domains and the self information of a mobile platform to repeatedly correct range ambulating trajectory so as to determine the minimum entropy, thus measuring whether the trajectory is well corrected or not; the slop ratio of the corresponding trajectory to the wavelength of an emitted signal is used for obtaining the non-fuzzy Doppler center frequency; and the measured frequency is improved by more than 5 times compared with Laden conversion. Thus, on the aspect of bi-static forward-looking and squinting synthetic aperture radar (SAR) Doppler center frequency, the invention has the characteristics of simple and accurate measurement, short processing time, high efficiency, strong instantaneity and capability of providing accurate and reliable data for subsequent high-precision imaging and motion compensation.
Owner:UNIV OF ELECTRONICS SCI & TECH OF CHINA

Verifiable and secure privacy amplification method based on quantum key distribution

The invention discloses a verifiable and secure privacy amplification method based on quantum key distribution. The method comprises the steps of S1, generating an initial random number string W, respectively generating random number strings K<mis,A> and K<mis,B> by two communication parties (Alice and Bob) in a base comparison process of quantum key distribution, and combining the two random number strings into a random number string W=[<Kmis,A>, K<mis,B>] by the Alice; S2, verifying randomness, after an error correction phase of the quantum key distribution is finished, estimating the minimum entropy lower limit of the W relative to an attacker Eve, wherein H<min>(W|E) is greater than or equal to 1-H<2>(e); S3, calculating a final secure key length N<f>; S4, extracting a perfect random string W*, through adoption of a partial pre-shared secure key of the two communication parties, constructing a Toeplitz matrix H<R>, and extracting the perfect random number string W* from the W according to the H<R>; S5, negotiating a universal hash function H<PA> through a public channel according to the W*; and S6, respectively carrying out hash operation on error corrected key strings by the two communication parties according to the H<PA>, and generating a final secure key. The method has the advantages of verifiability, security, easy realization and simplification of quantum key distribution system design and realization.
Owner:NAT UNIV OF DEFENSE TECH

Variational Bayesian inference-based high-speed target HRPP reconstruction method

The invention belongs to the field of radar signal processing, and relates to a variational Bayesian inference-based high-speed target HRPP reconstruction method. The method comprises the following steps of S1, carrying out sparse representation modeling on a target undersampled echo; S2, reconstructing a target HRPP through a variational Bayesian inference; and S3, estimating a target speed on through a newton iteration-based minimum entropy method: S3.1, calculating a first derivative, about the target speed, of an image entropy, S3.2, calculating second derivative, about the target speed, of the image entropy, and S3.3, estimating the target speed through a newton iterative. Through the method, high-speed moving target HRRP reconstruction under undersampling condition can be realized, target speeds can be effectively estimated from undersampled echoes under the condition of radar echo undersampling caused by the factors such as low signal to noise ratio, strong interference and thelike, and high-order phase errors imported by the target speeds can be compensated, so that distortions such as widening, defocusing and the like of target HRRPs are corrected, the target HRRPs with good focusing effect and high resolution are obtained, and an important engineering application value is provided for radar target recognition.
Owner:NAT UNIV OF DEFENSE TECH

Generation method and device for source independent continuous quantum random number

The invention puts forward a generation method and device for a source independent continuous quantum random number. The method comprises the following steps that: a continuous physical random source generates a continuous light field; the continuous light field is subjected to heterodyne detection, and meanwhile, two non-commutative mechanical quantities of the light field are measured, wherein the two non-commutative mechanical quantities are a component X (regular coordinate) and a component P (regular momentum); the continuous measurement results of the two mechanical quantities are discretized to independently obtain an initial random sequence under one component and a checking sequence under the other component; according to the checking sequence, the maximum entropy of a continuous random source is calculated; and through an entropy uncertainty principle and a maximum entropy calculation result, the conditional minimum entropy of the initial random sequence is obtained, and a completely random binary system true random sequence is obtained through postprocessing. By use of the method, additional random number does not need to be provided, the method does not depend on a hypothesis for sources, a "trusted" part in the physical random source can be effectively extracted, and the quantum random number is generated.
Owner:PEKING UNIV

Remote sensing image building detection and classification method based on global optimization decision

ActiveCN105184308AAccurate detection and classificationCharacter and pattern recognitionRadarMinimum entropy
A remote sensing image building detection and classification method comprises the following steps: acquiring DSM drawing data and visible light drawing data derived from an airborne radar laser; converting the size of the DSM drawing and performing the binarization of the DSM drawing; filtering the interference of the image edge, and merging the DSM drawing and the visible light drawing together; separating big and small white areas of the merged image, classifying the big areas through employing combination features, and deciding the features of the building classification of the small areas through employing the global optimization; classifying buildings according to preset threshold values of each feature, and calculating a branch having a minimum entropy; calculating a building area having a maximum purity in the branch; obtaining each feature weight through combining with the data, the maximal characteristic of the weight being this grade classification feature; and determining the sequence of the characteristics in order to realize the remote sensing image building detection and classification process. The remote sensing image building detection and classification method based on a global optimization decision may be used for the remote sensing image building detection and classification, has an important significance in the accurate detection and classification of the remote sensing image buildings, and has a broad market prospect and application value.
Owner:BEIHANG UNIV

Voltage sag source identification method based on mutual approximation entropy

ActiveCN109828184AReduced characteristicsReduce the problem that relies heavily on the accuracy of feature extractionFault locationSource typeMinimum entropy
The invention discloses a voltage sag source identification method based on mutual approximation entropy. The method comprises the steps of: (1) establishing a sample waveform library; (2) performingdata preprocessing; (3) calculating mutual approximate entropy values of a waveform to be matched and the sample waveform, and retaining the minimum entropy value therein and the information of the corresponding sample; and (4) performing sag source type identification: determining whether the minimum entropy value is in a threshold range or not, if not, determining that a pending result is reliable, namely, the waveform to be matched being the sag source type, or else, determining that the waveform to be matched does not belong to any one sag source type in the waveform library. The voltage sag source identification method has high accuracy at the aspect of actually measured waveform identification of the voltage sag source, is short in the required sampling window and simple and easy toimplement the algorithm, help engineers with correct determination of the voltage sag source types and the generation reasons to a certain extent to provide targeted theoretical guidance for treatmentof the voltage sag source problem, and has great application value and prospects.
Owner:SOUTHEAST UNIV

Frequency spectrum perception method and apparatus based on channel cluster

The invention relates to a frequency spectrum perception method and apparatus based on a channel cluster. The method comprises: according to historical detection data, counting the historical occupation state of each channel; according to the historical occupation state of each channel, respectively calculating a correlation coefficient between any two channels; according to the correlation coefficient, utilizing a channel cluster algorithm perform clustering on the channels, and generating a predetermined number of types; respectively selecting one detection channel from each type, and detecting the occupation states of the detection channels; according to the occupation states of the detection channels, performing occupation state intra-type estimation on other channels beside the detection channel in each type by use of an intra-type estimation algorithm; and according to the historical occupation states of each channel, performing occupation state self-estimation on other channels beside the detection channel in each type; and unifying two estimation results through a minimum entropy aggregation method. By using the method and apparatus provided by the invention, the quantity of the channels needing detection is substantially reduced, and enormous time and energy are saved for a frequency spectrum perception process.
Owner:BEIJING UNIV OF POSTS & TELECOMM

SAL (synthetic aperture ladar) full-aperture imaging method based on MEA (minimum entropy autofocus) and deramp

The invention discloses an SAL (synthetic aperture ladar) full-aperture imaging method based on MEA (minimum entropy autofocus) and deramp. With the method adopted, the problem of large movement errorbrought to echoes by the vibration of a carrying aircraft is solved. The method includes the following steps that: echo data signals are collected; range-direction pulse compression is performed on the received data; azimuth-direction deramp operation is performed on the range-direction pulse compressed data, so that the azimuth-direction focusing phase of the range-direction pulse compressed data can be compensated; a data block is divided into sub-apertures, phase error estimation is performed on sub-aperture data; sub-aperture phase errors are spliced, so that a full-aperture phase error is obtained; azimuth-direction phase error compensation is performed on the whole range-direction pulse compressed data; azimuth-direction derramp is carried out, the azimuth-direction pulse compression of the whole data of an SAL is achieved, the full-aperture imaging of the SAL is completed, and a high-resolution image is obtained. According to the method, sub-aperture division is performed on the data through a full-aperture imaging method; sub-aperture error phases are extracted through the MEA, all the error phases are spliced; overall phase compensation is performed on full-aperture data;and therefore, the utilization rate of original data is improved, estimated errors are more accurate, compensation is more effective, and the resolution of the imaging of the synthetic aperture laserradar is effectively improved. When the method is used for compensating high-order phase errors in the imaging of the synthetic aperture laser radar, a higher signal-to-noise ratio can be obtained, and the image resolution and image quality of the SAL can be improved.
Owner:XIDIAN UNIV

Ground penetrating radar wave velocity estimation method based on diffraction, imaging and minimum entropy technology

ActiveCN106443674AReduce the amount of search calculationReduce the amount of accumulated calculationsRadio wave reradiation/reflectionEstimation methodsMinimum entropy
The invention discloses a ground penetrating radar wave velocity estimation method based on diffraction, imaging and a minimum entropy technology. The method comprises the steps that a mean method is used to remove the direct wave component of an image; the normalized energy of the image in a two-dimensional direction is calculated, and an appropriate threshold is selected to determine a target interest region; the wave velocity range is determined according to the dielectric constant of a medium; for each wave velocity value, diffraction and the method are used to carry out synthetic aperture imaging on the image according to a target hyperbolic feature in the target interest region, and the entropy of the processed image is calculated; and finally the image corresponding to the minimum entropy is selected as the optimum imaging, and the corresponding wave velocity is the optimum wave velocity. According to the invention, the complexity of diffraction and processing is reduced by selecting the target interest region and setting a cumulative point horizontal position range; the image entropy is used to automatically determine the optimum imaging and the optimum velocity; the calculation amount is effectively reduced under the condition that the target information is completely kept; and the method has the advantages of simple calculation, high robustness and high estimation accuracy, and is suitable for engineering applications.
Owner:CHINA UNIV OF GEOSCIENCES (WUHAN)
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