Table of Content

20 October 2021, Volume 39 Issue 5

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Civil Aviation

Urban logistics UAV airspace capacity estimation based on conflict threshold

ZHAO Yifei ZHANG Zhiwei

2021, 39(5):  1-6. 

Asbtract ( 2094 )  

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With the development of logistics UAV in metropolises, the airspace capacity of urban logistics UAV has attracted great attention. The paper is based on the preliminary survey of the actual operation of urban logistics UAV. It induces the operation model of urban logistics UAV by referring to the acceptable conflict threshold as its capacity estimation. The airspace above the south campus of CAUC is chosen to estimate the logistics UAV airspace capacity. Impact factors have been analyzed with regard to the airspace capacity for flight simulation of logistics UAV. The study shows that the proposed model is applicable to the calculation of airspace capacity, airspace impact factor analysis, and airspace planning for urban logistics UAV. 

Research on Departure Flight Schedule Optimization of Pudong Airport Based on Capacity Flow Matching

YANG Lin , LI Chunzhu , ZHANG Nan , LU Tingting

2021, 39(5):  7-10. 

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The capacity of the area control sector is an important factor affecting the normality of flights. In order to reduce flight delays, based on the capacity and flow matching of the area control sector, while considering the airline's flight slot resource allocation袁the Shanghai Pudong International Airport's peak period flights are modeled and analyzed, with the shortest total flight delay time as the goal, with airport capacity, area control sector capacity, and flight schedule adjustments as constraints, the flight schedules were fine-tuned and optimized袁and software simulation is used to compare and verify the data obtained before and after optimization of flight schedules during the period. The results show that the optimization of Pudong Airport's flight schedule has greatly reduced the total flight delay time of the airport while ensuring that the airline's resource allocation remains basically unchanged.

Construction method of complex baseband signal for orthogonal frequency division multiplexing system

LIU Haitao, ZHANG Qi, LI Dongxia

2021, 39(5):  11-15. 

Asbtract ( 1742 )  

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Through the illustration of frequency domain of orthogonal frequency division multiplexing system, the construction method of complex baseband signal for LTE orthogonal frequency division multiplexing system based on LTE standard is analyzed and proposed to corroborate the proposed method, and a lower complexity engineering implementation method of complex baseband signal for orthogonal frequency division multiplexing system is also presented. An experimental environment based on Matlab, WinIQSim and radio frequency(RF) signal source is constructed and the proposed method is proved correct. 

Lubricating oil consumption prediction of civil aviation engine based on NRS-CNN

QU Hongchun, GAO Pengyu, ZHU Weihua, XU W angshan, GUO Longfei

2021, 39(5):  16-21. 

Asbtract ( 1984 )  

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with regard to the multiple parameters in multiple flight stages and the difficulty of accurately predicting lubricating oil consumption of civil aviation engines, a model based on neighborhood rough set (NRS) and convolutional neural network (CNN) is proposed. First, the NRS method is used to extract the flight phases that are more important to the oil consumption as feature parameters; second, the CNN is used to conduct an in-depth feature study with reference to flight phase parameters so as to make oil consumption prediction. The results show that the CNN can well complete the feature extraction of multiple oil parameters. The average absolute error between the prediction result and the actual value is 0.129 伊10 -3 m3 , and the average relative error is 3.8% , which can meet the needs of practical engineering applications and provide reference for evaluating the health status of civil aviation engine lubricating oil system.

Application of improved butterfly optimization algorithm in QAR data reconstruction

ZHANG Peng , LIU Y unyue , DUAN Zhaobin

2021, 39(5):  22-27. 

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Aiming at the problem that quick access recorder (QAR) data do not satisfy the data compatibility due to the systematical error of the measurement sensor, this paper transforms the parameter estimation problem of the systematical error into the function optimization problem on the solution space with butterfly optimization algorithm and the least squares criterion. In order to improve the performance of butterfly optimization algorithm, chaotic mapping is used to initialize the population and dynamically adjust the conversion probability. This method is applied to the correction and reconstruction of flight attitude angle and angular velocity of QAR data. The experimental results show that this method is simple and feasible, with high data reconstruction accuracy, and meets the requirements of data compatibility.

Overview on deflection-based identification methods of void beneath rigid pavements

LIU Hailun, LING Jianming

2021, 39(5):  28-33. 

Asbtract ( 1900 )  

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This paper aims to deepen researches on void detection beneath rigid pavements. Detailed investigation and analysis are made with regard to the academic research status, existing problems and development prospect about correlational research both at home and abroad. Firstly, the origin of deflection -based method and the commonly used deflectometer are respectively introduced; Secondly, the deflection-based identification methods are reviewed and the problems and application limitations in existing researches are analyzed in detail; Finally, the key issues and research trend for deflection -based identification of void beneath slab are presented. The difference between the effect of joint load transfer and void beneath rigid pavements on deflection is suggested to be the focus of further researches.

Influence of dowel bar misalignment on stress on cement concrete in airport pavement

WU Dalin, Y ANG Y ulan

2021, 39(5):  34-39. 

Asbtract ( 1640 )  

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The deflection of dowel bar will cause stress concentration on airport cement concrete pavement, and it is easier to damage the load transfer structure of pavement. In order to solve this problem, a finite element model of deflection of dowel bar on airport cement concrete pavement is established, and the stress concentration law of concrete under various deflection conditions with temperature shrinkage and aircraft load is analyzed. Simulation results show that when temperature contraction happens, the maximum principal stress increases approximately linearly with the increase of the seam width, and the greater the deflection angle, the bigger the growth rate. Under the action of aircraft load, the influence of horizontal deflection of dowel bar on the stress concentration of the wrapped concrete can be ignored, but the influence is obvious in the case of vertical deflection, especially in the case of opposite deflection of twin bars, the stress change degree is the largest and the working condition is the most unfavorable. Through the test, the finite element results of the deflection of a single dowel bar are verified. The verification results show that under the load, the bearing capacity of the structure is greatly reduced when the exposed part of the dowel bar turns away from the direction of the load action point. It is suggested that measures be taken in the construction to ensure that the dowel bar does not have vertical deflection.

Tourism route recommendation based on latent representation and improved collaborative filtering

WANG Hongjian

2021, 39(5):  40-43. 

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The existing tourism recommendation methods are limited because of the implicit feedback and extreme sparsity of tourism data sets. To solve the problem, an improved collaborative filtering algorithm based on embedding is proposed. Firstly, every route is represented as a low dimensional vector by using Doc2vector and every tourist is represented as a low dimensional vector based on all routes he/she had taken. Secondly, the co -occurrence routes between two tourists are obtained on the similarity of routes. Then the similarities among tourists are calculated according to the set of co-occurrence routes among them. Then, the routes are recommended by using the improved collaborative filtering. Finally, the method is proved to be effective on a real tourism data set.

Gate assignment optimization based on transit tension

XUE Qingwen, LANG Hong , WANG Yongzhi , LU Jian

2021, 39(5):  44-50. 

Asbtract ( 1915 )  

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Considering the process time, metro time and walking time of transit passengers, the transit tension parameter is proposed to evaluate the impact of boarding gate allocation on passengers transiting. A multi -objective and multi-constraint optimization model for gate allocation is established, which takes the transit tension of all transit passengers, the failure rate of flight allocation, and number of occupied boarding gates as the optimization objectives. The constraints including gate type and flight conflict are also taken into consideration. The bio - geography-based algorithm is adopted to solve the problem. The results show that 54 more flights are successfully allocated in the optimized model, increasing by 12% compared with the 'first -come -first -serve' scheme. The successful allocation rate of wide-body aircrafts is 100%. The proportion of passengers whose transit tension is lower than 1.0 takes 70%, and the number of successful transit passengers has increased by 30%. The overall transit tension has decreased by 25% . The current research can provide strategic support for boarding gate allocation with multiple terminals, alleviate the transit tension of passengers, and improve the efficiency of airport resource utilization.

Simulated flight training evaluation for flight cadets based on competency

WANG Y ue, Y ANG Y onggang, SONG Ze

2021, 39(5):  51-54. 

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With Prepar3D and its Software Development Kit, a simulated flight training evaluation platform is constructed. Based on the competency model, the platform selects typical flight procedure training subjects and their assessment indicators of flight technology, and the total score of subjects including two-level weights, which can more accurately and objectively evaluate the performance level of flight cadets, and which is more helpful for student pilots to understand the flight theory in depth. Practice has shown the feasibility of the flight simulation evaluation method and its effectiveness on the theoretical and practical learning of flight cadets in addition to high practical value.

Airworthiness Column

Study on aero-engine demand change model

WU Jingfeng , CHEN Yicheng , WANG Wei

2021, 39(5):  55-60. 

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Demand change management is vital in the R&D process of aero-engine project. First, the activity-based model method and the agent-based model method are compared and analyzed to examine the interaction characteristics of each stage in the demand change process; Then, the demand change agent model suitable for aero -engine organization structure is established by using Excel. Finally, the Agent model is used to analyze the impact of demand change on design quality and R&D risk, which provides theoretical guidance for engineers to carry out demand change management of aero-engine.

Airworthiness technology of civil aircraft cockpit security

MA Jian , GAO Binyuan , XIE Jiang

2021, 39(5):  61-64. 

Asbtract ( 1937 )  

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Cockpit security is vital for the safety of civil aviation transportation. Based on the background of regulation amendments, the relevant airworthiness requirements for cockpit intrusion resistance, penetration resistance, smoke protection, and the recommended compliance are investigated. The technical development and application of cockpit door design, monitoring system and smoke alarm are summarized. The points that need attention in future are presented, which provides support for civil aircraft design and airworthiness certification.