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Civil aviation noise is one of the main factors hindering the growth of the civil aviation industry. With the increase in global air traffic demand, the problem of aviation noise pollution will become more and more serious. It is of great significance to carry out research in aviation noise. First, by summarizing the characteristics of aviation noi...
Contexts in source publication
Context 1
... L Aeq, T metric solves two shortcomings of the L Amax . Figure 4 is the schematic diagram of L Aeq, T . The area of the red area in the figure is equal to the area of the blue area, that is, L Aeq, T metric averages the sound energy of the noise events to the measurement time period T . ...
Context 2
... L Aeq, T metric solves two shortcomings of the L Amax . Figure 4 is the schematic diagram of L Aeq, T . The area of the red area in the figure is equal to the area of the blue area, that is, L Aeq, T metric averages the sound energy of the noise events to the measurement time period T . ...
Citations
... Given that many residents living around small and medium-sized airports still suffer from noise problems, the development of digital noise assessment models has attracted the interest of many scholars. Digital aircraft noise assessment models can be divided into three categories: scientific models, best practice models [2], and machine learning models [11]. Scientific models focus on establishing specialized sound source models using physical methods to describe the sound generation mechanisms of multiple sound sources on aircraft. ...
... The corrected NPD data L re (P, d) under actual airport atmospheric conditions can be calculated using Eq. (11). ...
With the increasingly severe problem of aircraft noise pollution around airports, it is urgent to explore accurate and effective aircraft noise assessment methods. This article proposes a physics-based PSO-BPNN model based on the European Civil Aviation Conference (ECAC) best practice model, backpropagation neural network (BPNN), and particle swarm optimization (PSO) to enrich the methodology system of aircraft noise assessment. The primary modeling process is as follows. Firstly, based on airport parameters, flight information, and other data, the theoretical noise levels of ground monitoring point are calculated using the ECAC dynamic model. Then, a dataset containing measured noise values, theoretical noise values, trajectory data, and meteorological data is constructed to train the physics-based BPNN model, in order to correct the theoretical noise level. Finally, the PSO algorithm is introduced to optimize the parameters of the BPNN model and the construction of the physics-based PSO-BPNN model is completed. By taking Hefei Xinqiao International Airport (HFE) as a research case, the experimental results show that the physics-based PSO-BPNN model, which combines best practice model and machine learning model, demonstrates better performance than the ECAC model and physics-based BPNN model because of its balance between stability and flexibility. In the validation set, the error of 74.77 % of the predicted results was within ±3 dB(A), and the coefficient of determination R 2 between all predicted values and measured values reached 0.9450, which indicates the physics-based PSO-BPNN model a potential aircraft noise assessment solution.
... A printed antenna with multiple inputs and multiple outputs is introduced [39], and the maximum achievable gain obtained is satisfactory. The best practice model, scientific model and machine learning model are introduced [40]. The supersonic missile flight altitude and radar station location need to be considered. ...
To study the V-tail inclination of a supersonic missile that meet the requirements of low electromagnetic scattering characteristics in interval flight, an automatic tilt scheme is presented. The improved annealing algorithm is used to determine the optimal solution of the V-tail tilt angle, where multiple scattering of the physical optics plus physical theory of diffraction is used to calculate the radar cross section (RCS) of the target. The results show that the optimal solutions of V-tail inclination are different in various flight intervals of the horizontal observation field. In the forward side flight interval, changing the initial azimuth has less influence on the optimal solution of V-tail tilt angle, while more influence on the missile RCS indicator. In the side tail flight interval, the RCS level of the missile is low, and there is an optimal solution and a few feasible solutions for the V-tail inclination. The feasible solution of V-tail tilt angle in the lateral flight interval is obviously increased. The presented automatic tilt scheme is effective for studying the low scattering performance of the supersonic missile V-tail.
