一种实时抗干扰的列车节能-晚点恢复模型

列车占用、出清线路设备的时间受外部因素影响后会发生晚点现象.国内外普遍采用调整运行方案或运行曲线,即宏观或微观方法处理列车晚点问题.本文对列车晚点问题的研究现状做了详细分析,然后使用区间锁闭时间模型预测晚点增加与传播的范围,设计了一种实时抗干扰的列车节能-晚点恢复模型,使用微观方法避让受干扰区段,同时降低列车牵引能耗并缓解晚点现象.通过广铁集团CTC实时车次信息与相应区间参数制作的晚点场景,模型降低能耗与处理晚点的能力得到了验证.模拟计算表明：可降速的子区间越多,列车可避让的晚点时长越长;晚点较大时,则应使用更多数据或转化为宏观问题来解决.     

TPMS系统的应用

随着社会消费者安全意识的提高和安全法规标准的深入,汽车的另一项安全技术——TPMS轮胎气压监测系统正在广泛应用。通过对TPMS系统的组成、系统的标定及初始化学习的简要介绍,使读者了解TPMS轮胎气压检测系统的当前应用和发展方向。     

A route-based solution algorithm for dynamic user equilibrium assignments

The aim of this study is to establish a method to calculate good quality user equilibrium assignments under time varying conditions. For this purpose, it introduces a dynamic network loading method that can maintain correct flow propagation as well as flow conservation, and it shows a novel route-based solution algorithm. This novel algorithm turns out to be convenient and logically plausible compared to the conventional [Frank, M., Wolfe, P., 1956. An algorithm for quadratic programming. Naval Research Logistics Quarterly 3, 95–110] algorithm, because the former does not require evaluation of an objective function and it finds solutions maintaining correct flow propagation in the time-varying network conditions. The application of novel dynamic network loading method and solution algorithm to test networks shows that we can find high quality dynamic user equilibrium assignment. This is illustrated in an example network using the deterministic queuing model for a link performance function and associating costs and flows in a predictive way in discrete time.     

沥青混凝土复合型裂纹扩展行为数值模拟

应用线弹性断裂力学有限元程序,对一系列沥青混凝土偏直裂纹的扩展路径依据标准的三点弯曲梁试件解析。结果表明,随着预制裂纹偏离梁中线距离的增加,裂纹的起裂角和峰值荷载都增大。当集中荷载一定时,预制裂纹越长,应力强度因子越大;当预制裂纹长度与梁高比率a/W为0.4时,裂纹起裂角最大。I型应力强度因子和裂纹起裂角与比率a/W之间可分别用三次多项式很好地拟合。裂纹扩展路径总体上遵循一定的规律。试验结果表明,由于沥青混凝土材料颗粒的不均匀性,裂纹扩展路径通常沿着集料颗粒边界扩展而很少切断颗粒。虽然裂纹尖端处于I-II复合型应力状态下,但拉应力仍然是裂纹扩展的主要驱动力。     

充填型断续裂隙扩展行为的分析研究

目前岩体断续裂隙扩展行为的研究主要集中在闭合型或张开型裂隙上,缺少对充填型裂隙扩展行为的研究。实践表明,实际工程中岩体裂隙内往往存在充填物,且充填物对裂隙扩展有一定程度的影响。文中在滑动裂隙模型的基础上,针对充填型裂隙的特点,考虑裂隙内的传压系数和传剪系数,并根据节理裂隙法向变形的双曲线模型,推导了充填型断续裂隙的法向刚度,最终结合最大拉应力准则提出了压剪作用下充填型断续裂隙张拉裂纹起裂参数的计算方法。     

图解析方式的复合本体映射策略研究

针对本体复杂上下文关系,考虑不同输入模式,构建通用环境下的本体解析图描述。在结合本体结构基础上,建立多层本体结构图描述关系;引入上下文关联的相似度传播建立结构传播因子和实例传播算法;引入快速匹配算法用于本体的快速映射;最终提出一种复合本体映射策略,利用重用迭代得到本体的映射结果。最后通过算法复杂度的分析和一些对比测试证明了策略的可行性和有效性。     

基于RFID的道路交通拥堵信息识别模型

为推动交通智能化发展,引入射频自动识别技术获取道路上车辆运行信息,进行基于RFID的车辆信息采集框架设计。然后利用信息融合约简方法计算交通流特征值,最后根据速度、密度、流量三变量建立基于模糊层次分析的道路拥堵评价模型,判定道路交通拥堵级别,并在此基础上提出道路交通拥堵峰值异常和总体评价并行的预警机制。实验分析表明,该模型能够快速准确地确定当前道路的拥堵状态,及时预警拥堵路段,保证道路行车通畅和安全。     

流场中功能梯度材料圆柱壳的频散特性

文章基于Love壳体理论和Helmholtz波动方程推导了内外流场作用下功能梯度材料圆柱壳流固耦合振动方程。研究了流场作用下功能梯度壳内传播波的频散特性,并与各向同性圆柱壳进行比较。研究表明：在以拉伸和扭转运动为主的频段上,功能梯度壳体的材料特性改变对各支传播波相速度的影响较大,且扭转运动对应频段所受的影响大于拉伸运动对应的频段,而对弯曲波相速度的影响较小。该文可为水下航行器新型复合材料壳体的波动特性研究提供参考。     

Effectiveness of en route traffic information in developing countries using conventional discrete choice and neural‐network models

Providing commuters with traffic information or advising them of alternative routes during traffic incidents can alleviate congestion. For decades, advanced traveler information services (ATIS) have been devised and dedicated to this role. ATIS comprises a wide variety of technologies across the world, including radio traffic information (RTI) advisory service. RTI is common in both developed and developing countries. Although extensive literature and evaluation results of ATISs and RTI are available in developed countries, little attention has been devoted to that in developing countries. This work provides a modeling platform to study drivers' response to en route traffic information provided by Radio‐Payam broadcasting service in Tehran, the capital city of the developing country of Iran. The results are compared with counterpart cases in developed countries. Past studies and this study have employed conventional discrete models for drivers' response, such as ordered logit and ordered probit. This work evaluates the accuracy level of these conventional models in comparison with a developed neural‐network (NN) model, because it has been widely proven that NN models are highly precise. It has also been found that, apart from reliability, the conventional models are within an acceptable level of prediction accuracy compared with the NN models. The results show a high degree of similarities between the case of Tehran and its counterparts in the developing countries. The results also deliver some insights on how to improve or better implement the ATIS technologies. Copyright © 2012 John Wiley & Sons, Ltd.     

基于RFID技术的列车精确定位系统设计与试验

通过对目前列车定位技术的优缺点分析对比,提出将RFID技术运用于列车定位,同时用C语言开发了RFID（Radio frequency technology）列车定位控制系统,并在模拟实验台上对其进行了试验.试验表明：RFID技术能够独立完成列车的定位,高速阅读器识别电子标签并从中读取信息的速度为20 ms左右,满足高速铁路运输.试验中RFID技术定位精度为5 cm,可以直接定位区分复线中列车所在线路以及道岔处位置.无线射频技术具有一定的抗干扰能力,能适应多沙土和多雨水的恶劣自然环境,同时可以检测列车脱节问题.