Liu Jiaxue

Multilayered diffraction tomography algorithm for ground penetrating radar

A multilayered diffraction tomography algorithm for ground penetrating radar is derived in this paper. The algorithm considers the planar air-soil interface and uses the thought of the equivalent speed to solve the problem of multilayered medium. The first Born approximation and the dyadic Greens function are adopted to construct a linear forward model that inverted by fast Fourier transform to meet the requirement of small calculation, so we can real-time reconstruct the buried objects. Simulation results are provided to illustrate performance of this algorithm.

A neural network adaptive inverse controller for hypersonic vehicle

A structure of nonlinear adaptive inverse controller based on Radial Basis Function (RBF) network is proposed to control a hypersonic vehicle with highly nonlinear and strong coupled states. Different from conventional adaptive inverse controllers, the proposed one is constructed by one main controller called Trimmed Adaptive Inverse Controller and two compensators called Attitude Angle Compensator and State Compensator respectively. The Extended Minimum Resource Allocating Network (EMRAN) algorithm is adopted to train the RBF network on-line and off-line. The simulation results show that proposed adaptive inverse controller could lead the hypersonic vehicle to trace the expect input rapidly and steadily, and could adapt the different flight condition by online learning.

A method of aircraft fuel consumption performance evaluation based on RELAX signal separation

The fuel consumption performance of aircraft affects the deployment capacity and profitability of airlines. This paper focus on building a reasonable exponential attenuation model of aircraft fuel consumption performance model based on the actual flight data. In consideration of the feature that the flying distance varies with fuel consumption performance, a RELAX-based algorithm is introduced with the method of Non-homogeneousness Detect to attempt to realize the separation and parameter estimation of each component of fuel consumption model. The CRB analysis of the experiment results proved the accuracy of the parameter estimation while the A330 flight data showed the effectiveness of the algorithm. Meanwhile, it provided a reference criterion for aircraft fuel consumption performance evaluation.

Fault Simulation of Aircraft AC Power System Based on Bi-enabling Petri Net

Combined with fault injection method, Bi-enabling Petri Net model is proposed for fault simulation of Aircraft AC Power System. In the new model, add fault input and state-transition set to the traditional Petri net system, redefine the transition rules, and give its relation matrix description. Then, based on the relation matrix, a dynamic algorithm is proposed to establish the Bi-enabling Petri Net model of the components. Finally, through sharing composition of Petri net, get the integral model of AC Power System. Examples and simulation results show that this model can achieve the real-time control of AC BUS output and simulate the impacts of fault disturbances under various power configurations.

Image Denoising Using Adaptive Threshold Based on Second Generation Bandelets Transform

Second generation bandelets transform is a new method for image asymptotically optimal approximation based on capturing the geometric content of image. Relative to the first generation bandelets, the second generation is an construction of absolute discretization which can complete the image dissection through multi-scale analysis and geometric direction analysis. Bayes is an ideal estimation method of threshold. This paper perposes a novel denosing method based on second generation bandelets and bayes adaptive threshold, and makes full use of intrinsic geometry characters of image. Experiment on image denoising which the Lena and Barbara image are spliced with different level of gauss white noise shows that: compare to adaptive wavelet method, the algorithm perposed in this paper improves the peak signal-to-nosie ratio.