45results about How to "Reflect characteristics" patented technology

The invention discloses a system failure early warning method based on a baseline model and the Bayesian factor. The system failure early warning method based on the baseline model and the Bayesian factor can be applied to a dynamic complex system and particularly applied to early detection and warning of aerospace vehicle equipment failure. The method includes: using the multivariate state estimation technique to excavate the system 'individuation' baseline model on the basis of system state monitoring data; and using an actual measurement value of a system state parameter to subtract a baseline value so as to obtain a deviation value of a state parameter, analyzing a deviation value sequence by the aid of a Bayesian factor method, monitoring abnormalities of a sequence structure, and timely giving out failure early warning. The system failure early warning method based on the baseline model and the Bayesian factor solves the problems that dynamic complex system performance parameter deviation value dispersion is large, failure early characteristics are easily buried in noise, warning can be given out at the early stage of system failure, and sensitivity and robustness of the monitoring system are improved. Besides, the baseline model is easy to implement from the perspective of engineering, and the method is high in university and capable of meeting the requirements of the dynamic system on real-time monitoring.

The invention discloses an on-board GNSS marine reflection signal generation method. Marine reflection signals received by a GNSS receiver are in the form of the superposition of different time-delay reflection signals. Therefore, a time delay correlation curve of the marine reflection signals is formed through the superposition of the correlation curves of different time-delay reflection signals. Based on the above principle, it can be assumed that the amplitude values of n equal-delay-interval reflection signals are figured out based on the approximately fitting method, so that the powers of the reflection signals relative to direct signals can be further figured out. After that, the time delays of the n reflection signals relative to direct signals are figured out. The Doppler frequencies of the direct signals can be directly adopted as the Doppler frequencies of the reflection signals. In this way, the generation of GNSS marine reflection signals is realized based on the factors of time delay, Doppler frequency and power. The above generation method for complicated marine reflection signals is simplified based on the approximately fitting method, so that the simulation of the reflection signals is practicable and feasible. Therefore, the method lays a foundation for the development of GNSS reflection signal simulators.

The invention discloses a powder metallurgy random particle size distribution 3D (three-dimensional) finite element modeling and simulation method which includes the steps: firstly, acquiring the content and the particle size range of all components according to a powder metallurgy formula, calculating the average density of material particles according to the density and the content of different components, and acquiring the sizes and the number of the particles under a particle size belt; secondly, throwing the particles by PFC3D software, discretizing a random model and deriving throwing coordinates and particle sizes; thirdly, leading the coordinates and the particle sizes into ANSYS software and building a random 3D finite element model; fourthly, leading the finite element model into Hypermesh, dividing grids and finally loading a solver for finite element simulation to simulate the random model of a powder metallurgy random particle size distribution process. Main parameters include maximum particle size and minimum particle sizes. By making full use of randomization of discrete elements and strong analysis functions of finite elements, the model is visual, simple and high in practicability and conforms to application and research of present powder metallurgy in terms of sinter molding.