Table of Content

25 August 2018, Volume 36 Issue 4

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Civil Aviation

Optimization and simulation of departure aircraft taxiing path

XING Zhiwei, XU Mingyi, LUO Xiao, LUO Qian

2018, 36(4):  1-5,10. 

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Variable taxiing time is an important index to evaluate the characteristics of airport traffic flow, which affects airport operation efficiency, passenger satisfaction and pollutant emission. Taking a large domestic hub airport as instance, the aircraft departure traffic flow model is constructed. Through analyses of departure traffic flow characteristics and congestion rules during departure taxiing path, and according to cellular automata theory,traffic flow of airport taxiing area is regarded as airport network topology structure made of node and link, taking taxiing rule and possible conflicts between aircrafts as constrained control conditions. Monte-Carlo algorithm is employed to achieve optimal taxiing path and shortest taxiing time. Finally, model simulation is conducted based on operational flight data. Result shows that the current model can effectively reduce taxiing time of departure flights, alleviate traffic congestion, fully schedule and reasonably allocate airport ground resource.

Flight level identification based on kernel density estimation

XIE Chunsheng, LI Shaohua

2018, 36(4):  6-10. 

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With the opening of carbon trading market, safety operation and development of energy-saving emission reduction technology have become focuses of airline operation. A method of identifying the optimal flight level basing on flight data from airlines is presented. By analyzing the spatial characteristics of flight trajectory, difference matrix model basing on Hausdorff distance is established. The kernel density estimation method is used to degree identify prevalent flight trajectory. According to the relationship between flight path and flight level, a refined method of flight level identification is proposed. Finally, taking ZGNN-ZSNJ flight data of an airline as example,the optimal flight level can be effectively distingnished; meanwhile, the safety and economy of the current method is verified.

Chaotic characteristic analysis of control sector traffic indices

FENG Cheng, LIU Shuhan, GONG Qian

2018, 36(4):  11-14. 

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In order to deeply analyze the nonlinear characteristics of air traffic system, the chaotic characteristics of control sector are validated. Chaos theory and correlation analysis method are used for reference. Firstly, the mutual information method and pseudo nearest neighbor method are used to determine the time delay and embedding dimension, important parameters of phase space of the reconstructed time series are confirmed and then the largest Lyapunov index is calculated. Multiple sector samples of a control center are taken as objects, multiple indices are used to reflect the sector's traffic characteristics. Practical data calculating results show that there exists a general phenomenon of chaos in the following indices including number of aircrafts, average length of control, average control time, the number of flat flying aircrafts and minimum vertical spacing.

Ward system clustering and analysis of control operation sub-healthy state

YUE Rentian, JIA Tianqi

2018, 36(4):  15-19. 

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Control operation is an important part of the whole ATC system operation, and the confirmation of its state provides basis for unsafe accidents prevention. Firstly, evaluation variables of control operation state are analyzed and extracted from the aspect of controller workload. Secondly, 6 kinds of system cluster analyzing methods are used to classify the sample data, including single method, complete method, median method, average method,centroid method and Ward method. Summarizing the advantages and disadvantages of each method and their clustering results, final clustering results are obtained by ward method, basing on which, control operation state is divided into control operation healthy state and control operation sub-healthy state, and the latter one is then divided into control operation stable sub-healthy state and control operation unstable sub-healthy state. Analyzing results show that the classification is scientific and reliable, and is of great significance for the theoretical study of safety management.

Boundary point calculation and visualization of aerodrome OLS

LI Zongli

2018, 36(4):  20-23,28. 

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Accurate mapping of aerodrome OLS (obstacle limitation surface ) is the basis of exact calculation of object height limit in aerodrome clearance area. A calculating method of aerodrome OLS boundary point (intersection point) is proposed, realizing clearance OLS display through OvitalMap. The current method is simple, practical, accurate and efficient, which can intuitively calculate aerodrome OLS boundary point and realize visualization of civil aerodrome clearance management.

Real-time optimization of cruise flight profile for TOA controlling

HONG Wangjun, TANG Xinmin, CHEN Ping, GU Junwei

2018, 36(4):  24-28. 

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Precise control of TOA (time of arrival) can provide smart decision support of controlling flight profile for automatic control system. Flight distance is divided into multiple sections, and the fuel consumption model of aircraft in each section is established. Combining with real-time flight status data and ETA (estimated time of arrival), genetic algorithm is used to continuously adjust velocity acceleration of each evenly divided segment, so as to achieve precise control of TOA and realize flight profile optimization. Results prove that the current algorithm converges faster, and TOA error can be controlled within 依4 s, providing help for a new generation of control automation systems.

Crack development law of HPT rotor first stage blades based on SVR

CAO Huiling, WANG Xiaobing

2018, 36(4):  29-34. 

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Aiming at the potential safety problems caused by crack damage in Holes No.10~12 of first-stage rotor blades of aero-engine high pressure turbine, experiments are conducted. Firstly, crack damage data are obtained through ImageJ. Then, prediction model of crack damage length is established based on SVR, reliability of the model is tested. Finally, in-depth analysis on related influencing factors is made using the model. Results show that the crack length varies exponentially with the change of AQI（air quality index）, and it distributes in logarithmic order with the variation of CSN, EGT and N1. Moreover, the contribution rate of each related factor is quite different to the development of crack damage.

Research on procedure chapters of flight manuals based on CCAR29.1585

ZHANG Lu, GE Hongjuan, HU Mengjun, LIN Yi, XUE Jianliang, ZHAO Quan

2018, 36(4):  35-39. 

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In order to improve the practicability of the procedure chapters of transporting rotorcraft flight manuals and shorten the time of compilation and validation basing on analysis of CCAR29.1585. Firstly, the approval factors are analyzed, then review requirements for flight manual procedure chapters corresponding to the approval factors are proposed in details. Through research on existing rotorcraft flight manuals and relevant regulations in and abroad, suggestions on standardization of writing framework and content of procedure chapters are put forward to meet the requirements of CCAR29.1585. Finally, reasonable suggestions are given for AC313 flight manual procedure chapters improvement.

Performance study on cleaning agent for removing aircraft corrosion inhibiting compound

WANG Zhenliang, WU Yingwei, CHEN Yujing

2018, 36(4):  40-43. 

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Flammability and cleaning effect of 11 kinds of cleaning agents for removing aircraft CIC(corrosion inhibiting compound) are studied by test. Combining with toxic analyses of their main components, comprehensive performance of these cleaning agents are discussed. Results show that BD900, SKYKLEEN1000, CEEBEE A-954 and ARDROX 5503 have better comprehensive performance than others.

Engineering and Technology

Campus equipment monitoring system based on 6LoWPAN

ZHU Haiying, FENG Xingjie, ZHAO Junsong, GAO Jiangtao

2018, 36(4):  44-48,58. 

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Aiming at the' large quantity, scattered locations, backward managing means and low utilization efficiency'in the management of campus instrument and equipment. Combined with 6LoWPAN wireless sensor technology, a monitoring system of campus instrument and equipment is designed and realized based on wireless sensor network. Using the CC2538 system-on-chip system, the current, temperature and humidity are obtained by corresponding sensor and transmitted to remote data server by 6LoWPAN edge router. A judging method of equipment running state according to monitoring current is proposed to realize real-time monitoring, historical record and statistical analysis of the campus instrument and equipment. Practical test shows that this system is capable to conduct remote monitoring of the running state and operating environment information of campus instrument and equipment. It's of practical significance and for fine management of campus equipment, providing auxiliary support for decision-makers.

Efficient RAID-6 MDS code for degraded reads optimization

LAI Ran, FENG Xingjie, WANG Qing, LI Jie, JIAO Wenhuan

2018, 36(4):  49-53. 

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With the coming of Big Data Era and the development of modern storage systems, there is a big challenge in the reliability of storage systems in modern data center. Due to the fact that most classic RAID-6 MDS codes have limitations on degraded reads, a new RAID-6 MDS erasure code for optimizing the degraded reads is proposed,which adjusts the diagonal layout of X-code to horizontal direction by taking advantage of horizontal codes while the continuous data elements are more likely to share the same horizontal parity chain for optimizing degraded reads. Experimental results show that the optimized X-code can efficiently reduce the additional I/O requests for degraded read operations. Especially, compared with RDP code and X-code, the optimized X-code can obtain an improved performance with the same number of disks.

Stress analysis of laminated composite plate based on super mixed element

LIU Yanhong, ZHANG Ying

2018, 36(4):  54-57. 

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For finite element methods, calculating time of element numerical integration operation takes a large proportion.According to the characteristics of laminated composite plate structure, a super mixed element is constructed based on incompatible symplectic element of 3D linear elasticity problems. Since the assembly of super mixed element is a simple addition operation which consumes less time, the most obvious advantage of super element in the form of layers is saving the time consumed by repetitive integral operation of the same elements. The reliability of super mixed element is proven by example analysis.

Management Science

Static and dynamic empirical study on financing efficiency of strategic emerging industry

ZENG Gang, GENG Chengxuan

2018, 36(4):  59-64. 

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A static financing efficiency evaluation model is constructed employing nonparametric estimation Surper-SBM DEA model, the evaluating indicator system is built basing on equity, debt and endogenous financing. Meanwhile,dynamic evolution of financing efficiency is evaluated by using DEA-Malmquis index model from the perspective of time series. In the empirical research stage, 672 observation values of listed companies in strategic emerging industries of Tianjin are selected from 2010 to 2015. Static research results show that 93.7% of enterprises'financing efficiency is less than 1, which is almost in an inefficient state, and 80% of the sample enterprises with high financing efficiency are from the biological industry. According to the dynamic evaluation results, the average Malmquist index of sample companies during 6 years is 0.818, and the technological progress can influence the investment structure and proportion of equity financing, debt financing and endogenous financing.Finally, in order to promote the development of Tianjin strategic emerging industry, it is suggested to support the quantitative and qualitative increase of related enterprises from capital supply side, drive financing ecology optimization relying on technological innovation, and build a good financial support policy system.