机场场面交通流量预测方法研究

针对机场场面交通可获数据的局限性,为精准提取机场交通数据时空特征及预测场面交通流量。首先,基于推出控制理论,建立机场场面运行数值仿真模型,得到因数据局限无法获取的预测指标;其次,搭建卷积神经网络(CNN)与长短期记忆网络(LSTM)组合预测模型提取时空特征;最后,以河南郑州机场为例进行试验验证,比较模型在不同训练数据量下的预测性能与误差指标,结果表明基于仿真指标的预测模型预测结果精确度高且性能稳定。

天津机场登机口分配仿真与优化策略研究

基于天津滨海国际机场航站楼的实地调研,重点研究在日常运行登机口分配存在的问题,以最大流理论建立模型和优化算法,通过系统仿真的手段,提出登机口分配优化策略和方案。基于网络最大流理论和系统仿真的方法,由大量航班数据和机场的设施布局着手,考虑旅客步行距离、航空公司所属关系和运营等因素,提出可行有效的登机口分配优化策略。

混合进近运行下平行跑道进场容量评估

本文以仪表着陆系统(ILS,instrument landing system)和建立要求特殊授权的所需导航性能(RNP AR,required navigation performance authorization required)进近(EoR,established on RNP AR)混合程序为研究对象,探讨混合进近下跑道进场容量。首先,研究了飞机尾流消散和运动规律,提出混合进近条件下安全间距计算方法;其次,根据混合进近运行特征,建立混合进近平行跑道进场容量模型;最后,以昆明长水国际机场为例,构建全空域机场仿真模型,对模型进行验证,并在此基础上,设置多个运行场景对影响混合进近条件下跑道进场容量的因素,包括程序结构、机型和RNP AR能力飞机比例进行分析。研究结果表明:容量评估模型能够对混合进近运行下平行跑道进场容量进行精确、客观的评价;且固定半径转弯(RF,constant radius to fix)航段半径越大,跑道进场容量越大;RF航段半径为4~7 km时,RNP AR能力飞机比例越大,跑道进场容量越大;中型机比例越多,跑道进场容量越大。

跑道容量仿真模型分析

跑道容量是指在一定的运行条件下,跑道在特定时段内所能服务的起降飞机的最大架次数,对正确地估计跑道容量,减少机场延误有重要作用。在回顾以往的跑道容量计算模型的基础上,使用仿真软件建立单跑道机场的仿真模型,计算仪表飞行条件下单条跑道的容量和延误,并绘制出相应的容量-延误曲线。

Research on Numerical Simulation for Flow Field in a Jigger

Jigger is the main equipment in coal processing industry in China, which is developed towards large-scale device. By using the homemade device LTX-35 jigger as a model employing mesh division with non-orthogonal mesh for different kinds of through-flow passage, and completing the numerical simulation with the computational fluid dynamics (CDF) software-PHOENICS, the velocity distribution in different flow fields resulting from guide plates of varied structures are obtained. The results from the simulation show that 1 ) the degree of velocity uniformity of the flow field can be improved if a flat guide plate is replaced by a curved one in the jigger; 2) the best result can be achieved by using a semicircular guide plate.

Investigation of the correlation between internal gradients and dephasing effect in inhomogeneous field

Internal magnetic gradient plays a significant role in Nuclear Magnetic Resonance(NMR)measurements of fluid saturated porous media.The quantitative characterization and application of this physical phenomenon could effectively improve the accuracy of NMR measurements and interpretations.In this paper,by using the equivalent magnetic dipole method,the three-dimensional distribution of internal induced magnetic field and its gradients in the randomly packed water saturated glass beads are quantitatively characterized.By simulating the diffusive motion of water molecules in porous media with random walk method,the computational dephasing effects equation related to internal gradients is deduced.Thereafter,the echo amplitudes are obtained and the corresponding T2-G spectrum is also inverted.For the sake of verifying the simulation results,an experiment is carried out using the Halbach core analyzing system(B0=0.18 T,G=2.3 T/m)to detect the induced internal field and gradients.The simulation results indicate the equivalent internal gradient is a distribution of 0.1-0.3 T/m,which matched well with the experimental results.

A STUDY ON THE CHAOS MODEL OF LIQUIDITY IN STOCK MARKET

For a Stock Market,the critical problem is the maintenance of its liquidity.Market liquidity can be described in various ways,in particular, in terms of the bid/offer spread and the market depth.Model of market liquidity dynamics has been proposed in Schmidt,A.B.'literate.In our study,we improve his model.On one hand,we think that trading volume is determined by the total number of traders,as well as the relations between the numbers of buyers and sellers,while the model of Schmidt only considers the first item.On the other hand,Schmidt assumes that the number of “newcomers”in the market is in proportion to the current number of trades.However,we all know that the continual rise or fall of the price will also attract more buyers or sellers,that is,“newcomers”,into the market,which he has not taken for granted.We also prove it to be a chaos model through analysis of Lyapunov exponent.On the assumption that price variation can be neglected,we discuss the conditions in which chaos will emerge.Finally,we implement a computer simulation of the model in MATLAB,and get more interesting results.

Initial Value Sensitivity in Technology Diffusion

Initial value sensitivity in technology diffusion, an important problem for firms＇ decision making such as the timing and target market chosen for new technology or product entering the market, has long been limited by the research methodology and tool. Based on the network extension of Bass model, this paper proposes a stochastic threshold model and uses computer simulation to empirically examine three propositions on initial value sensitivity in technology diffusion process. Our findings suggest that diffusion extent is sensitive to not only the number of initial adopters but also their positions in social network, and the variance of customers＇ initial assessment as well, which can be detailed as follows： （1） the degree of technology diffusion exhibits highly positive relation to initial adopter quantity, in particular, when the quantity of initial adopters is small, diffusion extent is very sensitive; （2） diffusion extent is sensitive to the positions of initial adopters; （3） in addition, the variance of customers＇ initial evaluation displays strong negative relation to the final diffusion degree in that the larger variance, the lower of diffusion extent.