Table of Content

23 August 2019, Volume 37 Issue 4

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Civil Aviation

Four-dimensional trajectory prediction method based on ADS-B data mining#br#

MA Lan, GAO Yongsheng

2019, 37(4):  1-4. 

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Aiming at the big error of 4D trajectory prediction in air traffic control, a trajectory prediction method based on ADS-B data mining is proposed. Through deep mining on historical ADS-B flight data, statistical analyses on routes and aircraft types, data filtering, noise reduction and CURE cluster analysis of historical data are conducted. Taking trajectory data of Qingdao-Beijing CDG4651 flight as instance, the trajectory, over-time and over-height of the flight on a certain day are predicted. Result shows that the current method is accurate and practical.


Controller workload assessment based on sector complexity data analysis#br#

XU Chencheng, ZHAO Zheng, HU Minghua, JIANG Bing, KONG Hang

2019, 37(4):  5-10. 

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In order to effectively and accurately assess controller workload, data indicators of 13 sectors are firstly selected through questionnaire. Sector complexity data and controllers’ subjective self -evaluation value for their own workload are collected through radar control simulation experiments. Then, dimension reduction of sector data indices has been conducted through data application factor analysis and principal component analysis, which is simplified into a representative new principal component and used as an independent variable. After that, the regression equation is used to establish the controller workload prediction model, and the predicted value of the controller workload is obtained from the model. Finally, comparison between predicted value obtained from objective data analysis with the subjective self -evaluation value of controller workload verifies the model accuracy.


Optimized airport gate assignment based on combination of GA and TS#br#

SUN Shuguang, ZHANG Tai’rong

2019, 37(4):  11-14. 

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Aircraft shutdown process and airport gate assignment principle are analyzed to confirm the gate assignment constraints. Square of the minimum idle time and the maximum gate-using efficiency are taken as objective function to establish a suitable mathematical model. According to the priority level of aircraft gate assignment and taking into account the using rationality of parking space, a solution combining with GA and TS is proposed.Calculating results prove the optimization effect of GA: compared with random assignment, the objective function value is improved by 13%; after combining with TS, the optimization effect is improved by 14.4%.


Dynamic analysis on engineered material arresting system#br#

YIN Tao, RAN Zhenhua, WANG Youjie

2019, 37(4):  15-19. 

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EMAS dynamic model is constructed considering force of arresting materials on aircraft as focused force on landing gear which is related to arresting ratio and contact area. The mathematical description of this model is derived based on Lagrange equations; the arresting ratio is determined through experimental result fitting, which is compared with empirical formulae. Arresting process of B737-700 under certain laying conditions is calculated by numerical approach using relative material parameters, proving the rationality of the approach, analyzing the effect of runway laying and aircraft initial speed on arresting performance and providing a novel way for the dynamic simulation and analysis of runway arresting system.


Influence of aircraft emission on PM_2.5 concentration in airport area#br#

WANG Wei, WU Wenfei

2019, 37(4):  20-24. 

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To clarify the influence of aircraft operation on airport area and its atmosphere, aircraft sulfur emission parameters are modified, building the emission model of directly generated PM_2.5 and PM_2.5 precursor(NOX, SOX). Considering ground operation and flight procedure, three effective suggestions are proposed to decrease the influence of aircraft emissions on PM_2.5 concentration around airports.


Chinese airline network configuration based on time-space concentration degree#br#

LE Meilong, ZHENG Wenjuan, SHAO Jiajia

2019, 37(4):  25-30. 

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Index evaluation is used to empirically analyze the route network configuration of different types of airlines in China based on the degree of network spatial-temporal concentration. Rosenblas Index, which is used to evaluate concentration in industrial economics, is firstly introduced into air transport network combining with improved Gini Index, Relative Entropy Index and HHI Index to evaluate spatial concentration in airline network.Meanwhile, flight frequency cohesion degree is employed to evaluate network time concentration. By synthetically analyzing the spatial and temporal concentration of different types of airlines, the difference between network configurations are obtained. Analyses show that low-cost airlines have higher spatial concentration and lower time concentration, who mainly develop PP to HS route network; Besides Air China, which has higher spatial concentration and lower time concentration and is typically PP route network, other big full-server airlines are gradually transiting from PP to HS route network; With the expansion of scale, the spatial concentration of small and medium-sized full-service airlines gradually increases, while the time concentration basically remains unchanged, PP route network is mainly developed.


Risk assessment of airport security check system based on grey analytic hierarchy process#br#

Wang Qinqin

2019, 37(4):  31-35. 

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Ground operation is the basis of aviation security, and the prevention core is security check. Risk assessment of airport security system is important for aviation security. Seventeen risk factors of airport security system from four aspects(security personnel, equipment, environment and management) are identified, and the risk evaluation index system of the airport security system is built. Risk assessment model is established based on the gray analytic hierarchy process of airport security. The risk of an airport security system are evaluated as an example,and the calculated overall risk level is between normal risk and high risk. Research shows that the established model has good application value to the risk assessment of airport security system, providing basis for risk control.


Acoustic model building of radiotelephony communication based on DNN-HMM#br#

YANG Jinfeng, LI Kaitao, JIA Guimin, SHI Yihua

2019, 37(4):  36-40. 

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Due to the grammatical structure and pronunciation of radiotelephony communication, the acoustic model of generic speech recognition is not applicable to radiotelephony communication. An acoustic model constructing method of radiotelephony communication is proposed based on deep learning. DNN-HMM is used to extract the acoustic features. A professional database is built for model training, speech feature enhancing method is applied to improve the robustness of input speech features. Experiments are conducted to compare the influence of different speech features, feature dimensions and frame link sizes on the proposed model. Results show that the proposed acoustic model based on DNN-HMM is effective and the phoneme error rate can be reduced to 5.62%.


Risk assessment of civil aviation information system based on AHP and D-S evidence theory#br#

ZHANG Xiwu, LI Zhiping, LI Yuekai

2019, 37(4):  41-45. 

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Aim at the long period, complex process and strong subjectivity of experts in the traditional risk assessing procedure of civil aviation information system, a method based on AHP and improved D-S evidence theory is proposed. Firstly, the weights of each layer of factors relative to the upper layer are determined basing on AHP,and then a fuzzy comprehensive evaluation is used to give the commentary membership matrix of the lowest level factors; After that, through D-S synthesis algorithm based on matrix analysis and information entropy, the degree of conflict K between evidences is calculated and the evidence is re-weighted, obtaining the supporting degree of evidence for each factor; Final security level of the system is determined by comprehensive calculation.Compared with the widely used traditional fuzzy comprehensive evaluation method, the proposed method further decreases the expert subjectivity and is more efficient and easier to operate for safety risk assessment of civil aviation information system.


Influence of medium and small transport airport navigation on local economic growth#br#

YANG Bo, DUAN Saili

2019, 37(4):  46-51. 

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According to National Civil Airport Layout Planning released by State Council in 2008 and the data of 151 prefecture -level cities from 2005 to 2015, the influence of medium and small transport airports’ opening to navigation on local economy is measured using PSM-DID estimation method and case analysis. Result shows that medium and small transport airports navigation can promote GDP per capita by 21.1%


Engineering and Technology

Improved saturation mathematical PMSM model#br#

YANG Taipeng, SONG Jian, CAO Boshu

2019, 37(4):  52-56. 

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The coupling effect exists between dq axis of PMSM, it is necessary to establish three sheet of 2D data tables for self-inductance and mutual inductance using traditional saturation digital model, which requires a large amount of table lookup work. A given motor is analyzed using finite element software Ansys EM, the inductance parameters of dq axis are extracted to establish a saturation mathematical model with less inductance parameter lookup work, and is simulated on Matlab platform. Results show that the current model can accurately reflect the saturation electromagnetic characteristics of the motor. Compared with the traditional saturation digital model, the improved model reduces the lookup amount of the 2D induction table, and provides a simplified and reliable model basis for PMSM driving characteristics research and control system design.


Basic Science

Stopping distance of finite geometry LDPC codes over binary field#br#

GAO You, MA He

2019, 37(4):  57-59. 

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Stopping distance is an important parameter in the analysis of LDPC code performance under iterative decoding on a binary erasure channel. To study the stopping distance of finite geometry LDPC code over binary field, it is necessary to find a minimum stopping set from the parity -check matrix of the codes. According to the lower bound of stopping distance of finite geometry LDPC codes, a stopping set which reaches the lower bound is found by using the geometric properties of affine space and projective space. Then the stopping distance of finite geometry LDPC codes over binary filed in some special cases is obtained.


Temperature field simulation of CoCrAlY coated by Al film during HCPEB modification#br#

WANG Zhiping, SHEN Yue, HAN Zhiyong

2019, 37(4):  60-64. 

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To optimize the process parameters of HCPEB modification, and to obtain the optimal pulse time and electron beam energy density, FEM is used to simulate the temperature field distribution of electron beam bombardment process on CoCrAlY coated by Al film, analyzing the effects of pulse time and electron beam energy density on the surface alloying. Results show that when the thickness of aluminum film is 2 μm, the optimum combination of pulse time and electron beam energy density is 1.5 μs, 6 J/cm2, and the melting depth of the corresponding substrate is 0.2 μm. With the extension of pulse time, both the surface temperature and heat affected zone of the sample gradually increase. When the energy density is 4 J/cm2, the pulse time is appropriately extended to between 1.5 μs and 6 μs, which can achieve ideal electron beam modification and surface alloying effect.