基于图像色相值突变特征的钢轨区域快速识别方法

应用彩色图像中不同区域HSL色彩空间中色相值突变特征提取轨检图像中钢轨边界点, 对多条不同等分线处钢轨边界点进行直线拟合以确定钢轨边缘, 识别目标钢轨区域。分析了机器视觉轨检系统序列图像中轨枕、砟石、扣件与钢轨的分布特征及不同特征区域图像色相值的突变特征, 研究了轨检图像不同等分数值下等分线处色相值突变点与钢轨边界点的对应关系, 讨论了不同等分值对识别时间与识别失败率的影响。在不同光照条件下对识别方法与传统方法进行了对比分析。分析结果表明: 当等分值为8时识别效果最优, 识别失败率为5.0%, 识别时间为4.65 ms; 在500~1 000、1 000~10 000、10 000~100 000 lx三个特征光照强度区间, 识别方法在木枕与混凝土枕轨道中钢轨区域的平均最大识别时间分别为4.57、4.48 ms, 比传统方法分别减少了44.4%、47.1%, 识别时间标准差分别为0.15、0.12 ms, 比传统方法分别降低了91.8%、93.6%, 平均最大识别失败率分别为3.5%、3.3%, 比传统方法分别降低了66.0%、76.9%, 识别失败率标准差均为1.6%, 比传统方法分别降低了68.9%、71.1%。可见, 本文方法是一种机器视觉轨检系统中目标钢轨区域识别的有效方法。     

考虑楼板变形时框支剪力墙结构的框支层合理设计研究

将框支剪力墙结构沿竖向划分成为转换层上部剪力墙结构和转换层下部框架-剪力墙结构。对各部分结构假定质量刚度沿高度均匀分布,将楼板看成水平放置的深梁,并假定以剪切变形为主。根据平衡条件,列出微分方程组。采用相应的数学程序求解,得到结构水平侧移及各构件内力。通过对内力和侧移的双重控制,进行框支层的合理设计。     

CANoe和CAPL语言在整车级故障测试中的应用

故障测试是零件的重要测试之一,但在整车上故障测试则存在极大的限制。文章基于CANoe及CAPL语言实现的复杂报文发送功能,讨论CANoe和CAPL语言在纯电动汽车整车级故障测试的应用。     

突发事件下的城市轨道交通网络弹性评估

评估突发事件下的城市轨道交通(URT)网络弹性对于提升URT的运营水平具有重要意义.考虑URT网络拓扑结构及乘客出行影响,提出能够反映URT网络运营服务质量的网络性能指标,并以突发事件下网络性能的恢复速率为指标衡量了URT网络的弹性,以成都地铁网络为例进行了分析.结果表明:URT网络运营服务损失与突发事件持续时间成正比...     

地铁网络服务韧性评估与最优恢复策略

针对已有基于拓扑效率的地铁网络韧性指标无法反映地铁运营实际的不足,构建考虑线 路流量影响的路网服务效率指标和基于服务效率的路网服务韧性指标,以及基于路网服务效率 的节点重要度指标;提出以路网服务韧性最大化为目标的优化模型,并基于遗传算法求解模型获 得最优恢复策略。算例结果表明：分别以服务效率和拓扑效率作为路网性能指标,获得的失效节 点恢复次序明显不同;蓄意攻击下,最优恢复策略获得的路网服务韧性分别比基于重要度的优先 恢复策略、基于节点度的优先恢复策略和随机恢复策略高16.76%、72.11%和86.21%。上述结果 表明,必须根据地铁运营实际合理选择路网性能指标和恢复策略,否则可能得到次优甚至明显偏 离实际的方案,无法实现预期目标。     

Nonlinear pricing in linear cities with elastic demands

Nonlinear road pricing charges each traveler based on his/her trip’s corresponding particular attribute level. In order to help authorities in designing road pricing systems at a strategic level, this paper attempts to address two fundamental questions: (i) what is the value of pricing’s nonlinearity for mitigating traffic congestion? (ii) if a nonlinear toll function is implemented, should it be convex, concave or other shape? Specifically, we consider distance-based pricing in linear cities. For linear monocentric cities with heterogeneous travelers, we show that the system optimal distance-based pricing indeed exhibits nonlinearity. It is proved that: (i) the cost-based system optimal toll function is monotonically increasing and concave with respect to the traveled distance; (ii) the time-based system optimal toll function always exists and is unique. If the initial proportion of each traveler group is invariant along a corridor and the demand function is of exponential type, then the time-based system optimal toll function enables the travelers, living further away from a city center, to face a lower toll level per unit distance. For a linear polycentric city, we demonstrate: (i) there always exists the system optimal differentiated (in terms of city centers) toll functions; (ii) it is highly possible that the system optimal non-differentiated toll function does not exist. Hence, we further propose an optimal toll design model, prove the Lipschitz continuity of its objective and adopt a global-optimization algorithm to solve it.     

Distributed MPC for cooperative highway driving and energy-economy validation via microscopic simulations

Traffic congestion and energy issues have set a high bar for current ground transportation systems. With advances in vehicular communication technologies, collaborations of connected vehicles have becoming a fundamental block to build automated highway transportation systems of high efficiency. This paper presents a distributed optimal control scheme that takes into account macroscopic traffic management and microscopic vehicle dynamics to achieve efficiently cooperative highway driving. Critical traffic information beyond the scope of human perception is obtained from connected vehicles downstream to establish necessary traffic management mitigating congestion. With backpropagating traffic management advice, a connected vehicle having an adjustment intention exchanges control-oriented information with immediately connected neighbors to establish potential cooperation consensus, and to generate cooperative control actions. To achieve this goal, a distributed model predictive control (DMPC) scheme is developed accounting for driving safety and efficiency. By coupling the states of collaborators in the optimization index, connected vehicles achieve fundamental highway maneuvers cooperatively and optimally. The performance of the distributed control scheme and the energy-saving potential of conducting such cooperation are tested in a mixed highway traffic environment by the means of microscopic simulations.     

番禺气田珠海终端外涂层检测与失效分析

通过分析番禺气田珠海终端工艺管线涂层类型、涂层缺陷,根据涂层所处的腐蚀环境以及原始设计规范要求,结合影响涂层寿命的4个因素,对整个工艺管线按区域进行了涂层厚度检测与失效统计,评估了工艺管线外涂层的整体状况,分析了涂层腐蚀失效的原因.结果表明:终端管线外涂层存在缺陷,涂层厚度达不到设计要求,而焊缝及法兰出现的腐蚀主要由管线内外腐蚀环境、涂层质量及表面处理质量不好所致.     

大断面地铁车站隧道软弱围岩渐进破坏规律模型试验研究

以贵阳市地铁2号线阳明祠车站为背景,采用室内模型试验模拟大断面地铁车站施工过程中隧道塌方破坏过程,明确施工期间大断面隧道塌方破坏过程机制,对比分析围岩和路面的变形。结果表明:通过围岩重力作用模拟隧道施工过程中塌方过程,与实际塌方过程基本吻合,弥补了常规加载破坏的不足;围岩渐进破坏过程表现为裂隙出现-裂隙发展-裂隙贯通-围岩塌方,支护渐进破坏过程表现为变形缓慢增加-变形快速增加-裂缝快速发展-支护破坏;围岩渐进破坏与支护渐进破坏相互作用,共同发展;在实际施工过程中,当支护变形大幅增加时,应增加支护强度,同时还应及时注浆、打设长锚杆,以减缓围岩裂隙发展,阻断围岩渐进破坏过程。     

非收放式减摇鳍鳍轴校核算法研究

非收放式减摇鳍作为减摇鳍产品中非常重要的一个组成部分,而鳍轴也是其减摇力矩传力链中非常重要的一环,对于鳍轴综合应力的校核也就成了非收放式减摇鳍设计中的关键。通过比较考虑剪力的新算法以及仅做弯扭综合应力校核的2种算法,及它们在不同强度理论下的状态,综合讨论得出能使鳍轴应力值更加精确的算法。