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30results about How to "Realize quantitative description" patented technology

User portrait grouping and behavior analysis method and system based on log data of network security equipment

The invention discloses a user portrait grouping and behavior analysis method and system based on log data of network security equipment. The method mainly comprises the following steps: 1) extractingfeatures from data such as user logs of the network security equipment; 2) carrying out preprocessing and data analysis on the features to obtain relationships between the features and relationshipsbetween the features and user behaviors; 3) constructing a clustering model of the user groups according to the user characteristics; 4) establishing a user portrait according to the clustering model,and determining whether the user has abnormal behaviors or not according to a matching result of the user characteristics and the user portrait; the method is simple to implement and low in calculation complexity; the computing resource overhead of behavior analysis in the user log can be effectively reduced. Compared with the prior art, the invention does not need any additional mark, only needsthe data automatically recorded by the network security equipment, has the advantages of practical application, provides a user grouping method and a portrait matching method with different behaviormodes, and carries out decision-making judgment on whether the user behavior is abnormal or not.
Owner:XI AN JIAOTONG UNIV

Judging method of incompactness defect in node of concrete structure by detection by ultrasonic method

The invention relates to a judging method of an incompactness defect in a node of a concrete structure by detection by an ultrasonic method. On the basis of the traditional method for detecting the concrete defect by the ultrasonic method, besides an acoustic velocity and a head wave amplitude, two variable acoustic parameters, namely a complex frequency difference and a cross-correlation coefficient, are added; each acoustic parameter is processed into an acoustic parameter judging factor and each acoustic parameter judging factor is processed into a normalized comprehensive acoustic parameter judging factor; a position detecting chromatogram is drawn out according to the comprehensive acoustic parameter judging factor; and the position and range of a suspicious defect are determined according to a red area in the chromatogram. By the method, the compactness quality distribution of concrete can be directly and accurately described; errors and judgment loss caused by adoption of a single acoustic parameter for judgment can be avoided or reduced; and the difficulty in final judgment when the judgment result of the single acoustic parameter is inconsistent is also avoided. The judging method can be widely applied to the judgment of the incompactness defect in the node of the concrete structure or other complex structures.
Owner:BEIJING MUNICIPAL ENG RES INST +1

Fractal research method for evolution of overlaying strata fracture based on two-dimensional simulation test stand

The present invention discloses a fractal research method for evolution of an overlaying strata fracture based on a two-dimensional simulation test stand, comprising the following steps: (1) establishing a similar simulation test stand and setting a high-definition camera; (2) acquiring extension and development characteristics digital images of the overlaying strata fracture on the similar simulation test stand at different stages in the process of excavation; (3) processing the digital images acquired at each stage to obtain extension and development characteristics binary images of the upper overlaying strata fracture; (4) processing the obtained extension and development characteristics binary images of the upper overlaying strata fracture to obtain fractal dimension values of the extension and development characteristics of the upper overlaying strata fracture; (5) using a least square fitting in the fractal dimension to obtain a development characteristics fractal dimension fitting curve of the overlaying strata fracture; and (6) obtaining a relation curve between the fractal dimension and the extension and development characteristics of the overlaying strata fracture at eachstage. The invention achieves quantitative description on the morphological development of the fracture network field caused by migration of the overlaying strata, and finally provides the managementbasis for the morphological development of the overlaying strata fracture network under high-intensive mining.
Owner:CHINA UNIV OF MINING & TECH (BEIJING)

Method for obtaining airplane vertical occupation ratio

The invention relates to a method for acquiring the airplane vertical occupancy rate. The method comprises the following steps: the acquired flight flow sample data is processed to obtain the data information of all flights; the position information of each way point of the flights on the flight line and the flight information of the flights to pass through each way point are extracted from the data information of each flight; two flights are compared in sequence according to the position information of the way point and the flight information of the flights to pass through each way point to determine the number of the flight pair with collision risk; and the vertical occupancy rate is determined according to the number of the flight pair with collision risk. The flight pair with collision risk does not depend on the individual empiric parameter value, and not adopt the direct statistical method for the complex parameter. Therefore, not only the accuracy of the calculated vertical occupancy rate is high, but also the use is simple and convenient, and the invention is convenient for engineering realization, is favorable for the quantitative description of busyness of the aerial traffic to realize, provides the accurate data basis for the airspace running analysis and the safety assessment, and has wide application prospect.
Owner:BEIHANG UNIV

User risk degree evaluation method and system based on log data of network security equipment

The invention discloses a user risk degree evaluation method and system based on log data of network security equipment. The method comprises steps of extracting a user dangerous behavior list from the user behaviors and the enterprise specifications; extracting dangerous behavior characteristics of the user from data such as a network security equipment user log according to the dangerous behavior list; training a Gaussian mixture model on each dangerous behavior of the user according to the dangerous behavior characteristics of the user, obtaining a user risk grading probability set, designing a user risk grading probability fusion method based on an evidence fusion theory, and determining whether the user has a behavior abnormal risk or not according to a risk probability fusion resultof the user. The method is simple to implement and low in calculation complexity, can effectively reduce the calculation resource overhead of behavior analysis in the user log, does not need any additional mark, only needs the data automatically recorded by the network security equipment, has the advantages of practical application, provides a risk degree evaluation method for unifying different user standards, and carries out decision-making judgment on high-risk users needing early warning at the same time.
Owner:XI AN JIAOTONG UNIV

A new method of flow field characterization

The invention discloses a novel method for flow field characterization. The method comprises the steps of flow field characterization parameter set establishment, parameter weight determination, parameter standardization processing, flow field strength comprehensive characterization index establishment, flow field strength grading standard establishment and flow field distribution characteristic research. The beneficial effects of the invention are as follows: characterization parameters with the large influence degree are obtained through parameter optimization[ the membership degree and weight of each characterization parameter are determined by using fuzzy mathematics and an analytic hierarchy process; further, parameter coupling is carried out to form a unified characterization parameter; quantitative description of an oil reservoir flow field is realized; the flow field intensity index of each grid is calculated by using Eclipse numerical simulation software; the probability distribution of the reservoir is counted, the characterization indexes of the flow field and the potential are clear, the judgment standard and the regulation countermeasure of a regulation potential areaare determined, the flow field description, evaluation and reconstruction technology for the reservoir is formed, and technical support is provided for further improving the recovery ratio of an oil field.
Owner:PETROCHINA CO LTD

Post-stack seismic inversion method and device

The invention provides a post-stack seismic inversion method and device. The method comprises the steps that synthetic seismic data are obtained according to an initial model of wave impedance and actual seismic data; the initial model of wave impedance is optimized according to the actual seismic data and the synthetic seismic data so that first optimal wave impedance is obtained; high-pass filtering is performed on the first optimal wave impedance so that the high frequency inversion result of wave impedance is obtained; the actual seismic data envelopment is obtained according to the actual seismic data, and the synthetic seismic data envelopment is obtained according to the synthetic seismic data; the initial model of wave impedance is optimized according to the actual seismic data envelopment and the synthetic seismic data envelopment so that second optimal wave impedance is obtained; low-pass filtering is performed on the second optimal wave impedance so that the low frequency inversion result of wave impedance is obtained; and a final inversion result of wave impedance is obtained according to the high frequency inversion result of wave impedance and the low frequency inversion result of wave impedance. With application of the post-stack seismic inversion method and device, the inversion accuracy can be enhanced and quantitative description can be realized in reservoir prediction.
Owner:PETROCHINA CO LTD

Online planet landing trajectory optimization method based on non-uniform expansion ellipsoid

ActiveCN110686683ARealize online optimization solutionImprove evasion abilityInstruments for comonautical navigationLandformComplex topography
The invention, which belongs to the technical field of deep space exploration, discloses an online planet landing trajectory optimization method based on a non-uniform expansion ellipsoid. On the basis of the complex topography and landform of the celestial body surface, a non-uniform expansion ellipsoid model is established in position space by combining a current position and a speed estimationerror of a detector; a dynamic space margin and a maximum dangerous direction vector are calculated by combining the e obtained non-uniform expansion ellipsoid model according to an on-board obstacledetection result, so that real-time evaluation of a landing risk is realized; a landing trajectory optimization problem is formed based on the dynamic space margin and the maximum dangerous directionvector and the problem is solved in a rolling time domain by using a model prediction method and thus a descending trajectory is generated, so that the obstacle avoidance capability of the detector under the condition of uncertain state is enhanced on the premise of ensuring the on-board calculation efficiency and thus a safe and accurate landing target is completed. Therefore, the online optimization of the planet landing trajectory can be realized; and the safety of the detector in the planet landing process is improved.
Owner:BEIJING INSTITUTE OF TECHNOLOGYGY

Multi-communication network intelligent networking method for ship intelligent navigation

The invention discloses a multi-communication network intelligent networking method for intelligent ship navigation, and the method comprises the steps: analyzing the type of ship-shore communicationservice in intelligent ship navigation, grading communication demands according to service features into four grades; analyzing the available communication link performance of an intelligent ship in real time, wherein the available communication link performance comprises coverage, signal strength, transmission rate, time delay and the like; and adjusting the performance of the available communication link along with the change of the communication demands according to the change of the communication demands. According to the method, hierarchical management is carried out on a large number ofship-shore information interaction demands of intelligent navigation of the ship by adopting four grades of control, decision, perception and dynamics, priorities are sequentially 'control ', 'decision', 'perception ' and 'dynamics' from high to low, and a communication task is quantitatively described by using 'priorities, maximum receivable transmission delay, message size and whether four parameters need to be confirmed'.
Owner:CHINA TRANSPORT TELECOMM & INFORMATION CENT +1

Method for designing low-entropy and safe high-speed milling cutter and high-speed milling cutter

ActiveCN103624308AAchieving Design Across ScalesSolve problems that cannot be described quantitativelyMilling cuttersSpecial data processing applicationsMilling cutterEngineering
The invention relates to a milling cutter designing method and a milling cutter, in particular relates to a method for designing a low-entropy and safe high-speed milling cutter and the high-speed milling cutter, and aims to solve the problems that the entropy cannot be controlled due to disordering of particle swarms of the milling cutter and the safety of the high-speed milling cutter is reduced. According to the characteristic that the disordering of the particle swarms of a high-speed milling cutter assembly is associated with the reducing of the safety, a safety reducing process is described by virtue of an entropy determination method; by virtue of an entropy model, a mesoscopic motion state is judged, and the safety reducing process is determined; by virtue of an entropy control method, a control variable for controlling the safety reducing process is revealed, and the disordering of the particle swarms can be effectively controlled; macroscopic and mesoscopic structure parameters are collaboratively designed by virtue of a low-entropy high-speed milling cutter safety designing method; the safety and stability of the low-entropy milling cutter are verified. The diameter of the milling cutter is 63mm, the number of tool teeth is 4, the tool teeth are unequally distributed, included angles between the teeth are 88 degrees, 89 degrees, 90 degrees and 93 degrees, the tooth root of a tool body is of a chamfer and transition circular arc structure, and a front blade installation angle is 2 degrees. The method is applied to milling cuter designing and high-speed milling.
Owner:HARBIN UNIV OF SCI & TECH

Water traffic risk dynamic test method, medium and system

The invention discloses a water traffic risk dynamic test method, medium and system, and the method comprises the steps of building an internal information set of a water traffic system through the export of ship equipment, the collection of a maritime department, and the consultation, investigation and extraction of information of a captain, wherein the information set comprises navigation environment information, man-machine interaction information and ship-shore communication information; extracting and measuring non-uniform characteristics of internal information transmission of a water traffic system in combination with an information flow theory, and realizing water traffic risk dynamic characteristic extraction and analysis modeling by utilizing wavelet transform and spectral analysis; using a data driving method to construct a water traffic risk dynamic test model; and finally, inputting the abnormal characteristic value of the water traffic system information of the test water area into the risk dynamic test model to obtain a risk calculation value of the water area. According to the invention, the dynamic test of the water traffic risk can be rapidly realized, and the efficiency and pertinence of water traffic safety supervision are improved.
Owner:CHONGQING JIAOTONG UNIVERSITY

Test device and method for quantitative research of water inrush from coal seam floor

The invention discloses a test device and method for quantitative research of water inrush from a coal seam floor. The test device comprises a test box and a data acquisition detection system, wherein a cylindrical cavity is formed in the test box, the top of the test box is connected with a pressure machine, a hole is formed in a top plate at the top, a connecting pipe is arranged above the hole, and the other end of the connecting pipe is connected with a liquid collecting bottle; a visual window is arranged at the front end of the test box and connected with the cavity through a bolt; the data acquisition detection system comprises a high-speed camera and a stress-strain gauge, the test process is shot by use of the high-speed camera, a shot picture is used for following research and used as a basis of experimental data, and the stress-strain gauge collects stress change information during loading. The test method is implemented as follows: the visual window is arranged on the test box, scales are marked on the visual window, and the water inrush condition of the coal seam floor is monitored through the high-speed camera. The purpose of quantitative description of an experiment achieved, and the high requirements for research on water inrush from the coal seam floor at the current stage are met.
Owner:TAIYUAN UNIV OF TECH

Battery safety degree estimation method and estimation device based on second-order RC equivalent circuit model

The invention discloses a lithium ion power battery safety degree estimation method and an estimation device based on a second-order RC equivalent circuit model, and belongs to the technical field ofbattery safety degree estimation. The invention aims to solve the problem that the safety of the power battery cannot be quantitatively expressed and evaluated in the prior art. The method comprises the following steps: constructing a second-order RC equivalent circuit model; S2, identifying the parameters in the step S1 by using a least square method; obtaining a battery SOH according to the identified parameters; constructing a BP neural network, taking the ohmic internal resistance, the electrochemical polarization internal resistance, the concentration polarization internal resistance andthe battery SOH as neural network input, taking the battery safety degree as output for training, and inputting to-be-tested data into the trained model to obtain a real-time and accurate safety degree value. According to the method, the safety degree value of the power battery is estimated through historical data in combination with the second-order RC equivalent circuit model and the BP neural network model and is continuously corrected.
Owner:哈尔滨北方智能控制技术有限公司

Judging method of incompactness defect in node of concrete structure by detection by ultrasonic method

The invention relates to a judging method of an incompactness defect in a node of a concrete structure by detection by an ultrasonic method. On the basis of the traditional method for detecting the concrete defect by the ultrasonic method, besides an acoustic velocity and a head wave amplitude, two variable acoustic parameters, namely a complex frequency difference and a cross-correlation coefficient, are added; each acoustic parameter is processed into an acoustic parameter judging factor and each acoustic parameter judging factor is processed into a normalized comprehensive acoustic parameter judging factor; a position detecting chromatogram is drawn out according to the comprehensive acoustic parameter judging factor; and the position and range of a suspicious defect are determined according to a red area in the chromatogram. By the method, the compactness quality distribution of concrete can be directly and accurately described; errors and judgment loss caused by adoption of a single acoustic parameter for judgment can be avoided or reduced; and the difficulty in final judgment when the judgment result of the single acoustic parameter is inconsistent is also avoided. The judging method can be widely applied to the judgment of the incompactness defect in the node of the concrete structure or other complex structures.
Owner:BEIJING MUNICIPAL ENG RES INST +1

Post-stack seismic inversion method and device

The invention provides a post-stack seismic inversion method and device. The method comprises the steps that synthetic seismic data are obtained according to an initial model of wave impedance and actual seismic data; the initial model of wave impedance is optimized according to the actual seismic data and the synthetic seismic data so that first optimal wave impedance is obtained; high-pass filtering is performed on the first optimal wave impedance so that the high frequency inversion result of wave impedance is obtained; the actual seismic data envelopment is obtained according to the actual seismic data, and the synthetic seismic data envelopment is obtained according to the synthetic seismic data; the initial model of wave impedance is optimized according to the actual seismic data envelopment and the synthetic seismic data envelopment so that second optimal wave impedance is obtained; low-pass filtering is performed on the second optimal wave impedance so that the low frequency inversion result of wave impedance is obtained; and a final inversion result of wave impedance is obtained according to the high frequency inversion result of wave impedance and the low frequency inversion result of wave impedance. With application of the post-stack seismic inversion method and device, the inversion accuracy can be enhanced and quantitative description can be realized in reservoir prediction.
Owner:PETROCHINA CO LTD

Construction method and device of vehicle power-assisted steering model

The invention discloses a construction method and device of a vehicle power-assisted steering model, and relates to the technical field of automatic driving. According to the specific scheme, the method comprises the steps that a computer device obtains a mapping relation corresponding to each mapping mode in multiple mapping modes, each mapping relation is the relation between a power supply voltage signal of a motor of the vehicle and a power-assisted torque limiting value signal, and the multiple mapping relations are obtained through a double-slope hysteresis control algorithm; the method comprises the following steps: acquiring a plurality of mapping modes, acquiring a plurality of switching conditions existing in the plurality of mapping modes, establishing a vehicle power-assisted steering model according to a mapping relation corresponding to each mapping mode and the plurality of switching conditions, and establishing a library module according to the vehicle power-assisted steering model. According to the method, quantitative description of the complex nonlinear relation between the power supply voltage signal and the power-assisted torque limit value signal of the motor of the vehicle can be accurately and efficiently realized under a double-slope hysteresis control algorithm, and the universality of a vehicle power-assisted steering model is improved.
Owner:CHINA AUTOMOTIVE INNOVATION CORP

A test device and method for quantitatively studying water inrush from coal seam floor

The invention discloses a test device and method for quantitative research of water inrush from a coal seam floor. The test device comprises a test box and a data acquisition detection system, wherein a cylindrical cavity is formed in the test box, the top of the test box is connected with a pressure machine, a hole is formed in a top plate at the top, a connecting pipe is arranged above the hole, and the other end of the connecting pipe is connected with a liquid collecting bottle; a visual window is arranged at the front end of the test box and connected with the cavity through a bolt; the data acquisition detection system comprises a high-speed camera and a stress-strain gauge, the test process is shot by use of the high-speed camera, a shot picture is used for following research and used as a basis of experimental data, and the stress-strain gauge collects stress change information during loading. The test method is implemented as follows: the visual window is arranged on the test box, scales are marked on the visual window, and the water inrush condition of the coal seam floor is monitored through the high-speed camera. The purpose of quantitative description of an experiment achieved, and the high requirements for research on water inrush from the coal seam floor at the current stage are met.
Owner:TAIYUAN UNIV OF TECH

Method for obtaining airplane vertical occupation ratio

The invention relates to a method for acquiring the airplane vertical occupancy rate. The method comprises the following steps: the acquired flight flow sample data is processed to obtain the data information of all flights; the position information of each way point of the flights on the flight line and the flight information of the flights to pass through each way point are extracted from the data information of each flight; two flights are compared in sequence according to the position information of the way point and the flight information of the flights to pass through each way point to determine the number of the flight pair with collision risk; and the vertical occupancy rate is determined according to the number of the flight pair with collision risk. The flight pair with collision risk does not depend on the individual empiric parameter value, and not adopt the direct statistical method for the complex parameter. Therefore, not only the accuracy of the calculated vertical occupancy rate is high, but also the use is simple and convenient, and the invention is convenient for engineering realization, is favorable for the quantitative description of busyness of the aerial traffic to realize, provides the accurate data basis for the airspace running analysis and the safety assessment, and has wide application prospect.
Owner:BEIHANG UNIV

High-resolution heterogenous remote sensing collapsed building detection method

The invention discloses a high-resolution heterogenous remote sensing collapsed building detection method, which comprises the following steps of: firstly, constructing a unified optical-SAR ground object set based on an optical-SAR object set extraction strategy of the center of an inscribed circle of an object; then extracting high-level double-echo collapse semantic features in the SAR image based on a quantitative representation method of collapse semantic knowledge in double echoes; based on the four attributes of the area, the diagonal line, the rotational inertia and the standard deviation, a morphological attribute profile building extraction method is adopted to carry out bottom layer visual feature extraction on the optical image and the SAR image; and finally, collapsed building detection is carried out based on the improved active learning SVMs, and a collapsed building detection result is obtained. According to the method, complementary information between bottom-layer vision and high-layer semantics in multi-source data is mined, a collapsed building detection method combining post-earthquake high-resolution optics and SAR images is provided, dependence on pre-earthquake data is eliminated, and the method has important significance in timely emergency response.
Owner:南京佳芯图茂科技有限公司

Quantitative description method and system for wind speed profile of each position of mountainous region and wind speed determination method and system

The invention provides a quantitative description method and system for a wind speed profile of each position of a mountainous region, and a wind speed determination method and system, and the method comprises the steps: carrying out flow field simulation analysis based on a mountainous region rigid body boundary model, determining wind speed profile data, and extracting a point location prevailing wind direction and a wind speed sequence; determining a wind speed profile type and a corresponding wind speed profile objective function according to the relative position relationship between the active wind direction and the mountain selection point; fitting the corresponding wind speed sequence and the wind speed profile objective function according to each wind speed profile type to obtain parameters in the wind speed profile objective function, further determining a calculation formula of each wind speed profile type, and then calculating a wind load at any position of the tower body of the power transmission tower by using the calculation formula of the wind speed profile type corresponding to the wind speed profile type; the method and system aim to accurately reflect the influence of complex mountain land surface topography change on wind speed distribution along the height, accurately calculate the wind load of a tower body and further improve the safety and economical efficiency of an iron tower under the complex mountain conditions.
Owner:STATE GRID FUJIAN ELECTRIC POWER CO LTD +3

Sector sound wave relative amplitude calculation method based on attenuation rate scales

The invention discloses a sector sound wave relative amplitude calculation method based on attenuation rate scales. The method comprises the following steps of: 1) performing 3ft probe sound wave response consistency calibration on a sound wave variable-density measurement unit of a radial sound wave amplitude logging instrument; 2) performing sector sound wave probe sound wave response consistency calibration on the sound wave variable-density measurement unit of the radial sound wave amplitude logging instrument; 3) selecting a well section on a logging site, recording a plurality of pointsat fixed points by an instrument, and solving related scale parameters; 4) solving the attenuation rate ALKj sector sound wave amplitude of each sector sound wave of each measurement point on the basis of the related scale parameters; and 5) performing logging according to instrument requirements, and calculating and outputting the relative sound wave amplitude value of each sector. Therefore, foreach sector, the cement cementing rate of each sector can be solved according to an existing interpretation chart; and the quantitative description of the cement cementing quality of the sectors is realized, so that the curve quality and the interpretation accuracy are improved.
Owner:北京吉尔菲斯科技有限公司

A low-entropy safe high-speed milling cutter design method and high-speed milling cutter

ActiveCN103624308BAchieving Design Across ScalesSolve problems that cannot be described quantitativelyMilling cuttersSpecial data processing applicationsMilling cutterEngineering
The invention relates to a milling cutter designing method and a milling cutter, in particular relates to a method for designing a low-entropy and safe high-speed milling cutter and the high-speed milling cutter, and aims to solve the problems that the entropy cannot be controlled due to disordering of particle swarms of the milling cutter and the safety of the high-speed milling cutter is reduced. According to the characteristic that the disordering of the particle swarms of a high-speed milling cutter assembly is associated with the reducing of the safety, a safety reducing process is described by virtue of an entropy determination method; by virtue of an entropy model, a mesoscopic motion state is judged, and the safety reducing process is determined; by virtue of an entropy control method, a control variable for controlling the safety reducing process is revealed, and the disordering of the particle swarms can be effectively controlled; macroscopic and mesoscopic structure parameters are collaboratively designed by virtue of a low-entropy high-speed milling cutter safety designing method; the safety and stability of the low-entropy milling cutter are verified. The diameter of the milling cutter is 63mm, the number of tool teeth is 4, the tool teeth are unequally distributed, included angles between the teeth are 88 degrees, 89 degrees, 90 degrees and 93 degrees, the tooth root of a tool body is of a chamfer and transition circular arc structure, and a front blade installation angle is 2 degrees. The method is applied to milling cuter designing and high-speed milling.
Owner:HARBIN UNIV OF SCI & TECH

Aircraft structure credible interval response determination method

The invention discloses an aircraft structure credible interval response determination method. The method comprises the following steps: measuring sample points for acquiring parameters; representing the credibility information amount of the sample points by using an inverse distance entropy value, and determining an uncertain interval of a certain credibility corresponding to a single uncertain parameter in combination with a non-probabilistic credible set quantification theory; by utilizing a multi-dimensional space hyper-ellipsoid model for describing credible intervals of relevant parameters, providing a hyper-ellipsoid local coordinate system optimization solving method based on minimum volume surrounding, and obtaining an uncertain interval, corresponding to a certain credibility, of the relevant parameters in combination with a credible set quantification method of a single uncertain parameter; and solving uncertainty propagation by using a method including a Taylor expansion method to obtain an interval response of the structural response function containing credibility information. The uncertain interval of the corresponding aircraft structure response can be given according to the required credibility, and the method has the advantages of being simple, easy to implement and good in applicability in engineering application.
Owner:BEIHANG UNIV

Online Optimization Method of Planetary Landing Trajectory Based on Inhomogeneous Expanding Ellipsoid

ActiveCN110686683BRealize online optimization solutionImprove evasion abilityInstruments for comonautical navigationLandformComplex topography
The invention, which belongs to the technical field of deep space exploration, discloses an online planet landing trajectory optimization method based on a non-uniform expansion ellipsoid. On the basis of the complex topography and landform of the celestial body surface, a non-uniform expansion ellipsoid model is established in position space by combining a current position and a speed estimationerror of a detector; a dynamic space margin and a maximum dangerous direction vector are calculated by combining the e obtained non-uniform expansion ellipsoid model according to an on-board obstacledetection result, so that real-time evaluation of a landing risk is realized; a landing trajectory optimization problem is formed based on the dynamic space margin and the maximum dangerous directionvector and the problem is solved in a rolling time domain by using a model prediction method and thus a descending trajectory is generated, so that the obstacle avoidance capability of the detector under the condition of uncertain state is enhanced on the premise of ensuring the on-board calculation efficiency and thus a safe and accurate landing target is completed. Therefore, the online optimization of the planet landing trajectory can be realized; and the safety of the detector in the planet landing process is improved.
Owner:BEIJING INSTITUTE OF TECHNOLOGYGY

User risk assessment method and system based on network security device log data

The invention discloses a user risk degree evaluation method and system based on log data of network security equipment. The method comprises steps of extracting a user dangerous behavior list from the user behaviors and the enterprise specifications; extracting dangerous behavior characteristics of the user from data such as a network security equipment user log according to the dangerous behavior list; training a Gaussian mixture model on each dangerous behavior of the user according to the dangerous behavior characteristics of the user, obtaining a user risk grading probability set, designing a user risk grading probability fusion method based on an evidence fusion theory, and determining whether the user has a behavior abnormal risk or not according to a risk probability fusion resultof the user. The method is simple to implement and low in calculation complexity, can effectively reduce the calculation resource overhead of behavior analysis in the user log, does not need any additional mark, only needs the data automatically recorded by the network security equipment, has the advantages of practical application, provides a risk degree evaluation method for unifying different user standards, and carries out decision-making judgment on high-risk users needing early warning at the same time.
Owner:XI AN JIAOTONG UNIV
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