Mathematical model for optimising the sequence for clearing snow from the manoeuvring area during winter operations

This article considers the optimisation of the sequence for clearing snow from stretches of the manoeuvring area of an airport. This issue involves the optimisation of limited resources to remove snow from taxiways and runways thereby leaving them in an acceptable condition for operating aircraft. The airfield is divided into subsets of significant stretches for the purpose of operations and target times are established during which these are open to aircraft traffic. The document contains several mathematical models each with different functions, such as the end time of the process, the sum of the end times of each stretch and gap between the estimated and the real end times. During this process, we introduce different operating restrictions on partial fulfilment of the operational targets as applied to zones of special interest, or relating to the operation of the snow‐clearing machines. The problem is solved by optimisation based on linear programming. The article gives the results of the computational tests carried out on five distinct models of the manoeuvring area, which cover increasingly complex situations and larger areas. The mathematical model is particularised for the case of the manoeuvring area of Adolfo Suarez Madrid—Barajas Airport. Copyright © 2016 John Wiley & Sons, Ltd.

Highlights
• Optimal sequence for clearing snow from the manoeuvring area of an airport.
• Contains optimising algorithms solved using CPLEX LP‐based tree search.
• Restrictions on partial fulfilment of operational targets applied to subsets of significant stretches, used for planning the operation of snow‐clearing machines.
• Model applied to the case of the manoeuvring area of Adolfo Suárez Madrid Barajas Airport.
• Conclusions are given on the results of the computational tests carried out. There are five models of the manoeuvring area which cover increasingly complex situations and larger areas.

     

Short/medium-term prediction for the aviation emissions in the en route airspace considering the fluctuation in air traffic demand

This paper proposes a novel short/medium-term prediction method for aviation emissions distribution in en route airspace. An en route traffic demand model characterizing both the dynamics and the fluctuation of the actual traffic demand is developed, based on which the variation and the uncertainty of the short/medium-term traffic growth are predicted. Building on the demand forecast the Boeing Fuel Flow Method 2 is applied to estimate the fuel consumption and the resulting aviation emissions in the en route airspace. Based on the traffic demand prediction and the en route emissions estimation, an aviation emissions prediction model is built, which can be used to forecast the generation of en route emissions with uncertainty limits. The developed method is applied to a real data set from Hefei Area Control Center for the en route emission prediction in the next 5 years, with time granularities of both months and years. To validate the uncertainty limits associated with the emission prediction, this paper also presents the prediction results based on future traffic demand derived from the regression model widely adopted by FAA and Eurocontrol. The analysis of the case study shows that the proposed method can characterize well the dynamics and the fluctuation of the en route emissions, thereby providing satisfactory prediction results with appropriate uncertainty limits. The prediction results show a gradual growth at an average annual rate of 7.74%, and the monthly prediction results reveal distinct fluctuation patterns in the growth.     

基于能量法的气缸盖低周热机疲劳寿命预测方法研究

通过测试气缸盖本体解剖试样,获得气缸盖材料的循环应力应变特性,并利用仿真方法验证其合理性。在此基础上,依据发动机低周疲劳台架考核方法,运用子模型分析技术,得到考核循环内气缸盖火力面的应力分布和塑性变形特性。基于塑性应变能理论,结合试验测试,对火力面低周热机疲劳寿命进行预测和评估,分析表明排气鼻梁区的寿命较低,约为1100次。     

基于水动力—结构模型的VLGC强度和疲劳分析

超大型全冷式液化气船（VLGC）是国际上公认的设计及建造技术难度最大的船型之一,VLGC波浪载荷是船舶设计计算分析的重要载荷,准确的评估波浪载荷对船舶强度的设计非常重要。论文从DNV先进的水动力计算软件HydroD对VLGC船满载和压载工况下的波浪载荷进行了计算,得到了VLGC船相应工况下的运动响应和短期预报、长期预报值,并把计算出的波浪载荷传递到全船结构有限元结构模型中,加载分析得到了VLGC船的应力分布,对相应地方做了适当改进和加强,并对典型节点进行疲劳强度分析,得到了典型节点的疲劳寿命。对VLGC船整个波浪载荷传递到有限元模型的这一套流程做了分析和研究,也为进一步应用水动力方法计算其它船型的结构强度和疲劳寿命打下了良好的基础。     

基于秩约束的车辆遮挡点恢复方法

为了恢复车辆跟踪过程中丢失的特征点,提出了一种基于秩约束的车辆遮挡点恢复方法,该方法利用所有车辆图像点组成一个秩3的矩阵,并利用该特性构造一个投影矩阵,利用该投影矩阵求到车辆遮挡点,再将求到的车辆遮挡点代替图像中的车辆遮挡点,经过多次迭代,最后求到车辆遮挡点的真实位置。该方法的优点是所有的图像及图像点都平等地看待,模拟试验和真实试验表明,该方法具有鲁棒性好、收敛性好及误差小等优点。     

基于神经网络的公交客流预测

公交客流量具有动态性,受多种因素的影响,不能或无法用精确的数学模型进行预测。通过对公交客流量预测的Elman和BP神经网络的建立、学习和训练。并以前三年的公交客流量、国内生产总值、工业总产值、城市人口数作为两种神经网络的输入神经元,第四年的公交客流量作为输出神经元,同时以合肥市公交客流量为例进行分析,结果表明：所建的Elman模型比EBP模型的预测精度高,效果好。     

道路交通安全评价技术

交通安全评价能对交通系统中固有的或潜在的危险进行预测或评估,进而为采取措施改善交通安全现状提供依据。基于交通安全评价方法、事故预测模型和道路安全审计三个方面,有关道路交通安全评价方法和技术的优缺点及运用范围的介绍,可为相关研究提供一定参考。     

多元线性模型中的岭型预测

针对一般多元线性模型中常见的有偏预测--岭型预测与最优线性无偏预测的最优性判别进行了讨论,并就基于岭估计的最优预测量与经典预测量关于离差阵的最优性判别进行了探讨.     

通道交通量预测方法研究

通过对通道交通量预测方法的完善和系统化,从整体预测思路的角度出发,提出远景交通量的组成,并分析各组成部分的产生机理,给出简便可行的计算方法,有助于正确预测通道交通量。     

测量噪声相关情况下的航迹融合和测量融合

研究了测量噪声相关情况下的航迹融合和测量融合问题,根据线性无偏最小方差估计理论,推导了噪声相关情况下的多传感器跟踪系统的航迹融合和测量融合算法.经Monte Carlo仿真表明,文中给出的考虑噪声相关的航迹融合和测量融合算法的跟踪精度均高于相应的不考虑噪声相关的传统算法,且附加的计算量很小.