考虑轨道出行时空分布的断面客流预测

掌握列车区间段客流拥挤情况对列车运行调度有重要支撑作用。全线区间客流与站点分布、类型以及历史客流出行规律相关,提出具有时序化特征的出行引力因子对客流时空分布规律进行量化,选用长短期记忆人工神经网络(LSTM)处理该因子与区间客流间的关系。通过研究模型层数以及城市平均出行时间等对LSTM模型预测性能的影响,综合考虑全线区间客流总体平均绝对误差(MAE)和各轨道区间段客流MAE的离差以选择最佳预测模型。根据重庆市轨道历史数据,建立了时间步为3的双层LSTM模型预测重庆市轨道全线区间客流,结果表明:所提模型预测效果不仅优于时间序列模型,还优于直接将进出站客流作为LSTM输入的同类模型,能为城市轨道交通运营组织优化提供参考。

改进随机森林算法在北方河流测流断面形态预测中的应用

受汛期高洪水影响,水文站测流断面冲淤变化大,对流量测验精度产生较大影响。引入改进的随机森林算法,以北方典型测流断面为实例,综合断面流速、河流宽度以及河流水位3个影响因子进行测流断面形态的预测,基于断面形态预测结果对流量精度进行调整,从而提高流量测验精度。预测结果表明:该方式下断面测流流量误差有所减少,减少比例为5%～11%之间,可以作为水文站流量测验方式的一种有效补充。

路线设计中车辆行驶速度预测模型

在初定路线技术指标的条件下 ,综合考虑平面、纵断面和横断面三方面的影响 ,建立了行驶速度预测模型 ,用于检验、评价和控制技术指标和线形设计 ,达到线形协调和运行安全的目的。在纵断面预测中提出极限功率法的思路 ,在平面预测中引入了曲度 -路面宽度 -速度的方法。通过路段试验 ,实现了检验、评价线形设计的作用。

一缘煤业猴车(下山)大巷断面面积与矿井风量关系研究

和顺一缘煤业通风系统改造后,矿井进风系统的通风阻力成为制约矿井风量的关键,论文以进风大巷风速上限为基础,运用网络解算等手段,分别对矿井总进风量为13 000 m3/min和16 000 m3/min两种状态下,猴车大巷(进风斜井大巷)断面所需面积进行了计算,并解算不同状态下矿井主扇工况和矿井风量分布,为合理安排矿井采掘进度、规划未来矿井生产、制定矿井瓦斯抽采计划打下基础。

一缘煤业轨道运输巷断面面积与矿井风量关系研究

和顺一缘煤业矿井通风系统以各进风大巷风速上限为基础,运用网络解算等手段,分别对矿井总进风量为13 000 m3/min和16 000 m3/min两种状态下的轨道运输巷所需断面面积进行了计算,并解算出不同状态下矿井主扇工况和矿井风量分布,为合理安排矿井采掘进度、规划未来矿井生产、制定矿井瓦斯抽采计划打下基础。

基于改进灰狼算法优化LSTM的断面交通流预测

为提高断面交通流的预测性能,提出一种基于改进灰狼优化算法(IGWO)优化长短期记忆神经网络(LSTM)的断面交通流预测方法。首先,针对灰狼优化算法(GWO)中存在的狼群易陷入局部最优等问题提出了非线性收敛因子、基于SPM混沌映射的种群初始化和基于权重的位置更新策略3个方面的改进。其次,建立IGWO优化LSTM网络超参数的断面交通流预测模型(IGWO-LSTM),同时构建并行子模型。最后,将IGWO-LSTM应用于断面交通流预测,结果表明所提出的IGWO-LSTM模型在断面交通流中具有更好的预测性能。此外,还研究了所提出的模型在跨步断面交通流中的预测效果,以测试和验证所提出的模型。

Diffraction separation by plane-wave prediction filtering

Seismic data processing typically deals with seismic wave reflections and neglects wave diffraction that affect the resolution. As a general rule, wave diffractions are treated as noise in seismic data processing. However, wave diffractions generally originate from geological structures, such as fractures, karst caves, and faults. The wave diffraction energy is much weaker than that of the reflections. Therefore, even if wave diffractions can be traced back to their origin, their energy is masked by that of the reflections. Separating and imaging diffractions and reflections can improve the imaging accuracy of diffractive targets. Based on the geometrical differences between reflections and diffractions on the plane-wave record; that is, reflections are quasi-linear and diffractions are quasi-hyperbolic, we use plane-wave prediction fltering to separate the wave diffractions. First, we estimate the local slope of the seismic event using plane- wave destruction filtering and, then, we predict and extract the wave reflections based on the local slope. Thus, we obtain the diffracted wavefield by directly subtracting the reflected wavefield from the entire wavefield. Finally, we image the diffracted wavefield and obtain high-resolution diffractive target results. 2D SEG salt model data suggest that the plane-wave prediction filtering eliminates the phase reversal in the plane-wave destruction filtering and maintains the original wavefield phase, improving the accuracy of imaging heterogeneous objects.

基于手机信令数据的地铁乘客路径识别研究

随着轨道交通网络的发展,客流诱导与预警、应急管理、票务清分等问题变得更加棘手。传统方法是基于最短路径进行票务清分和断面客流预测,可结果与实际往往存在较大差异。票务清分的不合理会影响运营商利益,断面客流计算的不准确会影响地铁应急管理方案。现阶段部分学者基于位置数据识别乘客路径等特征,通过乘客实际路径解决票务清分、断面客流预测等问题,但都存在一定局限性。本文首先基于用户信令数据和站点经纬度数据识别地铁基站,再结合地铁基站过滤出乘客轨道交通系统内的位置数据,把站点作为图的节点,站点间的时间差作为权重,切分乘客当天全部轨道交通行程,利用节点的最短路径计算行程的进出站点、换乘点和时间,最终给出乘客完整路径。基于真实数据集进行实验,结果表明:基站识别算法对商A、运营商B、运营商C站点基站识别准确率分别为:79.197%、72.941%、92.893%;乘客路径识别算法对运营商A用户、运营商B用户、运营商C用户识别准确率为70%、70%、85%。

基于PSO-LSSVM算法的城市轨道交通断面客流量预测

为提高城市轨道交通服务水平和利用效率,针对非高峰期乘客等候时间过长、高峰期车厢满载率过高、列车运能浪费等现象,急需对具有非线性和随机波动特征的轨道交通最大断面客流实时准确预测,从而动态调整列车行车计划。首先,采集2017年4~6月份西安市轨道交通2号线全日分时段断面客流量为数据基础,将断面客流量划分为工作日、周末以及节假日的上行断面客流量和下行断面客流量。其次,利用前3 d各时段最大断面客流量以及前1 d各时段断面客流量作为模型输入变量,当天最大断面客流量作为模型输出变量,构建最小二乘支持向量机(LSSVM)核参数最优模型。然后,将RBF核、POLY核和Sigmoid核组合出多种备选核函数,以正则化参数、宽度参数、阶数参数和偏置参数为对象,利用粒子群算法(PSO)来优化备选函数和关键参数。最后,对不同模型中粒子群算法优化前后预测效果的回归评价指标和工作日、周末和节假日各时段回归误差进行比较分析。研究结果表明:粒子群算法寻优工作日LSSVM备选函数和关键参数后平均绝对百分比误差在5.0%以内,预测精度均有所改善;工作日上行的RBF与Sigmoid混合核,以及下行的RBF核能够在运行速度更快且精度更高条件下对断面客流量预测效果最优;PSO-LSSVM模型对工作日高峰期的断面客流量预测效果最优;相比PSO-LSSVM模型工作日较优的预测效果,其对周末和节假日上行的断面客流量具有一般预测效果。PSO寻优LSSVM核函数模型能更好解释工作日断面客流量的复杂变化,在小样本下达到较为理想的回归精度,具有良好的实用价值。

Failure analysis study of railway draw-hook coupler

Failure analysis of railway draw-hook coupler was carried out.The nondestructive testing method was undertaken on some failed couplers in service to designate critical areas of a coupler.Draw-Hook coupler is used to connect with the same hook coupler or automatic coupler.The influence of each connection types on the coupler strength in this study was discussed.A numerical stress analysis using FEM was performed,and many approaches including critical plane approach were carried out on fatigue life prediction of coupler under different conditions.The results of the proposed fatigue criterion and fatigue life predictions,as well as static numerical analysis,are validated with experimental results.

Techniques for Surveying Urban Active Faults by Seismic Methods

Using the seismic method to detect active faults directly below cities is an irreplaceable prospecting technique. The seismic method can precisely determine the fault position. Seismic method itself can hardly determine the geological age of fault. However, by considering in connection with the borehole data and the standard geological cross-section of the surveyed area, the geological age of reflected wave group can be qualitatively (or semi-quantitatively) determined from the seismic depth profile. To determine the upper terminal point of active faults directly below city, it is necessary to use the high-resolution seismic reflection technique. To effectively determine the geometric feature of deep faults, especially to determine the relation between deep and shallow fracture structures, the seismic reflection method is better than the seismic refraction method.

Prediction of the Maximum Flow by the Model SASIS： Sensibility to the Empirical Parameters of the Shape of the Furrow

The model developed in this research presents effective mechanisms in simulations of a discharge strip understood between the minimum and the maximum allowable values, aiming to determine the relationship between discharge and water application efficiency, deep percolation and runoff rates, and consequently to optimize the performance of the furrow irrigation systems with continuous flow. The flow applied in each furrow must be adapted to the length, to the field slope and to the nature of the ground. The authors studied the maximum non erosive flow （Q,,,~）, in function of parameters obtained from the dimensions of the furrow, being Pl and/92, respectively, the linear and exponential parameters of the potential functions that described the relationship between the area of the cross section of flow （or wetted perimeter） and height of flow; in this way, the multiplicative effect of,01 on the area of the cross section of flow is linear, while ,02 is exponential. It verified a conjugated effect of,or and p20n the value of Q,,~. The results of this research point out for the importance of having an estimate of the parameters of the geometry of the cross section of flow （,01 and ,02） the most precise as possible, being known that the dimensions of this section can result in impracticable values of Qmax, outside of the acceptable strip in the literature, that is from 1.2 to 4.0 L.sl. This sensibility analysis was also of great benefit to create an interface in the software SASIS, capable to guide the user of this tool in the input of appropriate values for ,01 and P2 to the process of simulation of the irrigation for furrow with continuous flow and of the optimization of its performance.

不完备信息下公交断面客流的推算模型

为解决不完备交通数据信息下城市公交线路的断面客流量的计算问题,以断面客流的预测为研究对象,探讨了公交车站下车客流的预测模型。运用区段覆盖的思想,将公交沿线以客流集散点为中心划分成不同的客流分布区段。结合各站点的区位条件、客流条件建立不同区段内的公交分担率模型。以此为基础结合公交IC卡上车客流数据构建各车站的下车客流预测模型,结合上车客流、下车客流与断面客流三者的关系模型,计算得到公交断面客流量。最后以西安市某条公交线路某个时段的上车刷卡数据为例进行了模型的适用性分析,统计该条线路沿线各个站点周边300 m吸引范围内的土地利用性质以及人口密度,采用改进的遗传算法对模型中的未知参数进行标定。结果显示,待确定参数α和β分别取0.419 1和0.482 3时目标函数取得最优解,利用标定的结果计算该线路各车站的下车客流,进而求得断面客流量。通过与实际跟车调查结果对比,运用构建的模型预测得到的断面客流量与实际值存在一定的差异,平均相对误差在23%以内,平均绝对误差约为5人/断面,从整体结果来看预测的断面客流的变化趋势与实际调查断面客流情况基本一致,表明构建的模型具有一定的可靠性。