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187 results about "Dynamic Bayesian network" patented technology

A Dynamic Bayesian Network (DBN) is a Bayesian network (BN) which relates variables to each other over adjacent time steps. This is often called a Two-Timeslice BN (2TBN) because it says that at any point in time T, the value of a variable can be calculated from the internal regressors and the immediate prior value (time T-1). DBNs were developed by Paul Dagum in the early 1990s at Stanford University's Section on Medical Informatics. Dagum developed DBNs to unify and extend traditional linear state-space models such as Kalman filters, linear and normal forecasting models such as ARMA and simple dependency models such as hidden Markov models into a general probabilistic representation and inference mechanism for arbitrary nonlinear and non-normal time-dependent domains.

A modeling method of hybrid fault early warning model and hybrid fault early warning model

InactiveCN102262690AGuarantee intrinsic safetySpecial data processing applicationsOperabilitySystem failure
The embodiment of the invention provides a modeling method of an early warning model of mixed failures and a modeling system. The modeling method provided by the invention comprises the following steps of: generating a function analyzing module on the basis of HAZOP (Hazard and Operability Analysis) or FMEA (Failure Mode and Effects Analysis); generating a degeneration analyzing module on the basis of FMEA analyzing results and a theory of stochastic processes; generating an accident analyzing module according to state monitoring data and maintenance action information; generating an action analyzing module according to output results of the function analyzing module and the degeneration analyzing module through combining a DBN (Dynamic Bayesian Network) theory; taking the output of the accident analyzing module as an inference evidence and utilizing a DBN inference algorithm to process forward and backward inferences in the same time period to generate an evaluating module for outputting factors and consequences of system failures; taking the output results of the evaluating module and the accident analyzing module as the inference evidence and utilizing the DBN inference algorithm to process forward and backward inferences in the different time periods to generate a predicating module for outputting prospective degeneration tendencies of each member of the system. The model provided by the invention can be used for tracking the failure factors of the system and inferring possible failure consequences and probability.
Owner:CHINA UNIV OF PETROLEUM (BEIJING)

Fault diagnosis and pre-warning system in oil refining production process and establishment method thereof

ActiveCN104238545AStrong fault propagationStrong fault tracing and reasoning abilityElectric testing/monitoringOperabilityEngineering
The invention provides a fault diagnosis and pre-warning system in the oil refining production process and an establishment method of the fault diagnosis and pre-warning system. The method comprises the steps of establishing a multilevel flow model in the oil refining production process, determining a fault propagation path, conducting hazard and operability (HAZOP) analysis on the oil refining production process, determining a plurality of static nodes and a plurality of dynamic nodes, determining the connected relation of the static nodes and the dynamic nodes, establishing at least one alternative model, adopting the dynamic Bayesian network structure scoring mechanism for scoring of the alternative models, determining the alternative model with the highest score as a fault multilevel related model, determining the conditional probability relation between the static nodes and the dynamic nodes in the fault multilevel related model, and establishing a fault diagnosis and pre-warning module. The established fault multilevel related model and the fault diagnosis and pre-warning module have the higher fault propagation and fault tracing and reasoning capability, and accurate diagnosis and timely warning of faults generated in the oil refining production process can be achieved.
Owner:CHINA UNIV OF PETROLEUM (BEIJING) +1

Vehicle trajectory predicting method based on hybrid dynamic bayesian networks and gaussian process

ActiveCN110304075AImprove scalabilityControl devicesCognitionUncertainty representation
The invention belongs to the technical field of automatic vehicle driving environment cognition and decision-making, and especially relates to a vehicle trajectory predicting method based on hybrid dynamic bayesian networks and gaussian process. According to the method, parameters of MDBN and GP are learned through natural vehicle driving data, and a plurality of vehicle kinematic models are combined through utilizing MDBN, so that short-term trajectory prediction and estimated probabilities of driving intention and driving characteristics are obtained, and then long-term trajectory predictionand representation of uncertainty prediction are conducted through using GP. By adopting the method, short-term prediction characteristics based on a vehicle physical movement model as well as long-term trajectory prediction and representation of uncertainty prediction according to driver information can both taken into account. Compared to an existing vehicle trajectory predicting method, vehicle models, abstract intention and data driving are combined together, and the expansibility of the MDBN model and the GP model are strong, and thus the method is suitable for different driving scenarios and can combine more effective situational information like road information and traffic information.
Owner:TSINGHUA UNIV

Intersection collision-avoiding method based on dynamic Bayes network

ActiveCN105761548AOvercome the defect of needing to know all the current status information of the vehicleAvoid complex vehicle trajectory prediction processAnti-collision systemsComputation complexityDriver/operator
The invention discloses an intersection collision-avoiding method based on a dynamic Bayes network, and mainly solves the problems that an existing algorithm is not well adapted to the complex road layout of an intersection, a large amount of data processing is needed, and the calculation complexity is high and the time complexity is high. The method comprises the steps of: 1) determining vehicle states, road conditions and driver behavior information, and adopting the dynamic Bayes network to carry out modeling on vehicle state evolution; 2) determining the safe driving behavior of a target vehicle according to the current environment conditions; and 3) deriving the intention behavior of the driver at the intersection, carrying out risk estimation based on comparison between the safe driving behavior and the intention behavior, and when potential risks are detected, taking different measures according to the practical condition for avoiding a collision. According to the invention, the complex vehicle track prediction process is avoided, the calculation amount is reduced, the vehicle collision in other scenes can be flexibly avoided, and the method can be applied to an intelligent traffic system.
Owner:XIDIAN UNIV

Method of planning three dimensional route of unmanned plane by means of improved artificial fish swarm algorithm

The invention discloses a method of planning three dimensional route of an unmanned plane by means of an improved artificial fish swarm algorithm. The method of planning three dimensional route of an unmanned plane by means of an improved artificial fish swarm algorithm is used for carrying out static state planning of route and real-time dynamic re-planning of route when an unmanned plane executes a single task. The method of planning three dimensional route of an unmanned plane by means of an improved artificial fish swarm algorithm includes the steps: constructing a digital map through a landform model and a simplified threat model, considering the influence of space division granularity on the complexity of an optimizing control algorithm, and realizing division of space according to a fence self-adaptive algorithm; realizing static state route planning by means of an improved artificial fish swarm algorithm; and considering the time factor, constructing a threat prediction model based on a dynamic Bayesian network, predicting the unexpected threat, combined with flight constraint of the unmanned plane, obtaining the re-planning starting point, and realizing global route dynamic re-planning by means of the improved artificial fish swarm algorithm. The method of planning three dimensional route of an unmanned plane by means of an improved artificial fish swarm algorithm has the advantages of reducing the complexity of a route optimizing control algorithm, improving the optimum route searching capability, and satisfying the practical route planning demand.
Owner:NANCHANG HANGKONG UNIVERSITY

Expressway road traffic state estimation method based on dynamic Bayesian network

The invention belongs to the technical field of road traffic detection and particularly discloses an expressway road traffic state estimation method based on a dynamic Bayesian network; the method comprises the following steps: (1) extracting relevant parameters of the road traffic state as nodes; (2) determining an interrelationship among the nodes and establishing the dynamic Bayesian network; (3) carrying out a fuzzy classification on data of the observable nodes, analyzing the historical data to obtain a clustering center of each classification and determining a membership degree of the data of the observable data, belonging to each classification; 4) for a target node selected in the dynamic Bayesian network, acquiring a corresponding conditional probability and a transition probability and establishing each moment characteristic table of the selected target node; 5) inputting road traffic flow parameters of the current moment to the dynamic Bayesian network and triggering to reason a target of each moment to obtain a traffic state estimation result. According to the expressway road traffic state estimation method disclosed by the invention, the uncertainty in a single parameter estimation state is solved and simultaneously the relevance in the traffic state is considered, so that better effect and reliability when the road traffic state is estimated are achieved.
Owner:重庆科知源科技有限公司

Meteorological threat assessment method based on discrete dynamic Bayesian network

The invention discloses a meteorological threat assessment method based on a discrete dynamic Bayesian network. The method comprises the following steps: collecting an observed weather type, intensity information and UAV (Unmanned Aerial Vehicle) position and attitude information; performing a quantization treatment according to a divided quantization level, and establishing an observation evidence list; using expert knowledge or experience to establish a conditional probability transfer matrix between states, and determining a state transfer matrix between time slices; establishing a discrete dynamic Bayesian network model between a meteorological threat level, a meteorological factor and the UAV; and using a Hidden Markov Model reasoning algorithm to calculate the final meteorological threat level. The meteorological threat assessment method based on the discrete dynamic Bayesian network provided by the invention realizes the organic combination of a continuous observation value and the discrete dynamic Bayesian network, and reasons out the probability distribution of a meteorological threat degree in combination with the HMM (Hidden Markov Model) reasoning algorithm, so that the effectiveness, the practicability and the accuracy of meteorological assessment can be greatly improved.
Owner:WUHAN UNIV OF TECH

Real-time estimating method for high-grade road traffic flow running risks

ActiveCN104751642AReal-time prediction of traffic flow operation riskImprove forecast accuracyRoad vehicles traffic controlSimulationRoad accident
The invention belongs to the field of traffic safety and intelligent traffic management control, in particular to a real-time estimating method for high-grade road traffic flow running risks. The real-time estimating method for the high-grade road traffic flow running risks considers the problem that a high-grade road short of fixed-point traffic flow collecting facility is incapable of acquiring the road traffic flow rate, occupancy and the like traffic parameters. The real-time estimating method for high-grade road traffic flow running risks includes that using traffic flow speed data acquired through different traffic information collecting technologies to build a real-time accident forecasting model, using a dynamic Bayesian network model to consider the speed state data of several time periods, building relationships between the traffic flow state and accident risks, and estimating the accident in real time so as to early warn or regulate a vehicle to avoid an accident. The real-time estimating method for the high-grade road traffic flow running risks has good forecasting precision for the high-grade road accident risks through speed data, and the real-time estimating method for the high-grade road traffic flow running risks has broad practical application value.
Owner:TONGJI UNIV

Mechanical system rime varying reliability evaluating method based on dynamic Bayesian network

The invention discloses a mechanical system time varying reliability evaluating method based on a dynamic Bayesian network. The mechanical system time varying reliability evaluating method comprises a first stage of determining model basic indexes, a second stage of structuring the structure of the Bayesian network and a third stage of updating a formula and the time varying reliability of a Monte Carlo simulation computer mechanical system according to Bayesian information. The mechanical system time varying reliability evaluating method has the advantages that a knowledge diagrammatic expression method is provided through the Bayesian network, directed diagrammatic expression can be carried out on the cause and effect probability relation between node variables, and the cause and effect probability relation can be used for uncertain knowledge expression, cause and effect reasoning, diagnosis reasoning and the like. The weak link of the reliability of the system can be effectively recognized through reasoning of the Bayesian network; the relation between components in the mechanical system becomes more visual and clear through diagrammatic display, the dynamic Bayesian network technology is applied to evaluation of the time varying reliability of the mechanical system, the multiple states and failure correlation of the mechanical system are analyzed, and a theoretical support is provided for improving the performance and the reliability of the mechanical system.
Owner:UNIV OF ELECTRONICS SCI & TECH OF CHINA

Equipment state identification method based on Markov model and probability network

The invention relates to an equipment state identification method based on a Markov model and a probability network. The state of equipment is identified using a hierarchical hidden Markov model (HHMM), and the identification result can be calculated more accurately in the form of probability. In view of the problem that the model parameters exponentially increase with the increase of equipment states, a dynamic Bayesian network is introduced to reduce the computational complexity of the model and shorten the inference time. HHMM is expressed as a dynamic Bayesian network. The health state of equipment is identified with the help of a preprocessed vibration signal. In view of the limitation of the existing state classification method, a state number optimization method based on a K-means algorithm and a cross verification method is presented. Through the state number optimization method, the stages in the process of fault development can be divided more accurately to lay a foundation for the accurate identification of equipment states. The change of the health state can be detected before functional failure, and the remaining life of equipment can be predicted using a trained model according to the change observed in the current behavior.
Owner:SHANGHAI UNIVERSITY OF ELECTRIC POWER

Method for analyzing reliability of turbine blade disk system of aircraft engine

The invention discloses a method for analyzing reliability of a turbine blade disk system of an aircraft engine. The method comprises the following steps of: establishing a system chart; establishing a system dynamic bayesian network and a system failure-mode dynamic bayesian network model; discretizing and transforming the dynamic bayesian network into multiple static bayesian networks; structurally decomposing the static bayesian networks into simply-connected regional networks and multiply-connected regional networks; performing bidirectional derivation on the simply-connected regional networks by a static bayesian network inference method; and performing bidirectional derivation on the multiply-connected regional networks by a bucket elimination method to respectively solve the failure rate of the turbine blade disk system, namely a system element, of the aircraft engine, and the fault rate of each failure mode. According to the method for analyzing the reliability of the turbine blade disk system of the aircraft engine, the problems of complicated expression, low computational efficiency, combinatorial explosion and the like, which are caused when traditional reliability analyzing methods are used for analyzing large-scaled, complicated and dynamic structures, are solved, and the computational efficiency is enhanced.
Owner:UNIV OF ELECTRONICS SCI & TECH OF CHINA
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