CRH3型动车组辅助变流器半实物仿真系统

基于对CRH3型动车组辅助变流器电路结构、控制器K1及其接口的分析,采用的模拟方案有:使用电磁继电器模拟接触器的闭合和关断;使用常闭按钮开关模拟熔断器、主风扇M30和变压器超温保护的反馈触点;采用反相器将IGBT的控制信号取反,以模拟IGBT的反馈信号;设置2个可调电阻用以模拟功率模块进风口和出风口的PT100温度传感器,并通过调节电流实现对主风扇M30的控制。采用Matlab软件的Simulink工具箱建立辅助变流器半实物仿真系统主电路的仿真模型,在Matlab软件的实时开发环境(Real-Time Win-dows Target,RTW)模块中经过模型分析、代码转换、程序生成并运行联编文件等步骤,获取该模型的可执行文件。运行该可执行文件,通过选择外部模式、构造、连接目标机、运行等步骤,再打开控制器K1,实现半实物仿真系统和控制器的协同工作。使用Visual Basic软件开发该仿真模型的人机界面。实践证明,这一方式完全能满足设计需求,同时又具有较高的性价比。该辅助变流器半实物仿真系统已经成为辅助变流器国产化设计的重要工具。     

Real-Time Bus Arrival Information System: An Empirical Evaluation

The provision of real-time information concerning bus arrival times could potentially reduce the uncertainty associated with public transport trips and improve the overall level of service. In addition, real-time predictions might enable operators to apply proactive control strategies. Even though considerable research efforts were devoted to the development of bus arrival prediction schemes, there is a lack of knowledge on the performance of real-world operational systems. This article aims to investigate the performance of a commonly deployed real-time information generation scheme. A conventionally used scheme is implemented and evaluated based on an empirical analysis. Performance metrics concerning the prediction error accuracy and reliability and their impact on expected waiting time were formulated from both passengers’ and operators’ perspectives. The real-time information generator was applied on the trunk line network in Stockholm, Sweden. The accuracy and reliability of the prediction scheme was analyzed by comparing the generated predictions against vehicle positioning data. This scheme was found to systematically underestimate the remaining waiting time by 6.2% on average. The provision of real-time information yields a waiting time estimate that is more than twice as close to the actual waiting times than the timetable. This difference in waiting time expectations is equivalent to 30% of the average waiting time.     

有时间窗车辆路径问题的混合算法

提出了一种基于模拟退火算法（SA）和大规模邻域搜索（LNS）的混合算法,并采用PFIH算法构造较高质量的初始解,同时给出了一种调整客户时间窗的回归迭代策略,从而计算出每辆车的最佳出发时间,并证明这种策略可使每辆车的等待时间均为零。从试验结果可以看出,该算法用于求解VRPTW问题效果显著,计算速度较快;与其他算法相比,显示了其较强的实用性和可操作性,为解决VRPTW提供了一种有效的算法。     

浅谈网络计划的工期-成本优化在公路工程管理中的应用

介绍网络计划中的工期、成本优化及在公路工程管理中的应用.     

时间序列法预测沥青路面损坏状况指数研究

由于沥青路面损坏状况影响因素很多,因此要准确预测路面损坏状况较困难。文章采用时间序列法建立预测模型,结合同三高速公路（上海段）路面损坏状况的实测数据进行预测分析。分析结果表明时间序列法具有较高的预测精度和易修正性。     

Incorporating time and income constraints in dynamic agent-based models of activity generation and time use: Approach and illustration

Existing theories and models in economics and transportation treat households’ decisions regarding allocation of time and income to activities as a resource-allocation optimization problem. This stands in contrast with the dynamic nature of day-by-day activity-travel choices. Therefore, in the present paper we propose a different approach to model activity generation and allocation decisions of individuals and households that acknowledges the dynamic nature of the behavior. A dynamic representation of time and money allocation decisions is necessary to properly understand the impact of new technologies on day to day variations in travel and activity patterns and on performance of transportation systems. We propose an agent-based model where agents, rather than acting on the basis of a resource allocation solution for a given time period, make resource allocation decisions on a day-by-day basis taking into account day-varying conditions and at the same time respecting available budgets over a longer time horizon. Agents that share a household interact and allocate household tasks and budgets among each other. We introduce the agent-based model and formally discuss the properties of the model. The approach is illustrated on the basis of simulation of behavior in time and space.     

Time series prediction based on LSTM neural network for top tension response of umbilical cables

The umbilical cable is an essential component of offshore oil and gas extraction systems. The severe marine environment poses a high challenge to the safety of the umbilical cable structure during operation. The analysis of an umbilical cable requires complex and resource-demanding finite element time-domain simulations to obtain their nonlinear dynamic response. Therefore, in order to solve the problem of structural safety monitoring and real-time assessment of remaining life of umbilical cables under extreme sea states, there is a great need to predict the dynamic response of umbilical cables quickly and accurately during operation, for ease of making fast decisions for system operation and maintenance before the arrival of extreme sea states. Given the strong nonlinear function-approximation ability of the neural network, this study proposes an efficient method for the prediction of the time series of umbilical cable top tension response based on LSTM (long short-term memory) neural network. We use LSTM neural network and ARIMA (autoregressive integrated moving average) model in a real engineering case for time series prediction of the top tension response of the umbilical cable, and the results of the two models are analyzed and compared, and the efficiency and accuracy of the LSTM neural network model are verified. Furthermore, the hyperparameter, dataset and generalization ability of LSTM model are discussed. The results indicate that feasibility of the tension response prediction of umbilical cables under dynamic load in complex marine environments.     

基于公交准时化的时刻表制定方法研究

公交准时化是公共交通发展的必然趋势,公交到站时刻表是公交准时化的具体体现,制定公交时刻表既能提高了公交的运营效率,又提升了公交服务水平,同时为乘客提供了更为准确的辅助信息。本文提出两种时刻袁计算模型,由对公交车跟车调查的数据,得到公交车在相关站点间的行程时间,再对该行程时间进行分析统计,得出相应的期望与95％置信区间,最后选择计算模型得到公交车在各站点的到站时刻表,并对时刻表信息的发布作了介绍。     

带回程取货的逆向物流车辆路径建模及其蚁群算法

对逆向物流车辆路径问题进行了概述和分类,构建了以VRPPDTW为基础的带回程取货的逆向物流车辆路径数学模型,设计了求解该模型的最大-最小蚁群算法,对设计要素进行了详细介绍,包括初始蚁群分布,状态转移策略,以及信息素更新策略等,并给出了具体的算法步骤. 最后,以Solomon中的R101、R102、R103、R104和R105等5项示例为背景,分别取前25节点和50节点,以取货点的取货量比例分别占全部客户节点需求量的10％、30％、50％取货,得到30个算例的计算结果,并将其与Tangian和模拟退火等计算结果进行了比较,结果表明最大-最小蚁群算法在某种程度上优于其他算法     

一种能防霜的侧窗玻璃结构

介绍一种能防霜的低成本侧窗结构,供北方寒冷地区客运车使用,增加乘客视野,减少乘客晕车。