改进粒子群算法的行人设施客流适应度博弈分析

为了有效改善交通枢纽内部行人设施的运行状况,提出交通枢纽行人设施客流适应度的概念,以此对交通枢纽的服务水平进行量化分析。同时,将粒子群算法进行改进,并应用于行人设施客流适应度的博弈分析。各行人设施对应粒子的每一维参与博弈,通过粒子位置的更新实现参与博弈的行人设施控制参数的更新,经过博弈迭代搜索到交通枢纽行人设施客流适应度的最优值及对应的各行人设施的控制参数。仿真实例表明:该方法对实际交通枢纽中行人设施的组织优化具有一定的应用价值。     

客车车身骨架构造与优化分析

在当前我国经济快速发展的今天,人们对交通工具的需求也在逐渐提高,传统的客车以其快速平稳的优势越来越受到人们的欢迎,且这一交通工具本身的灵活性较强,能够适应各种路况。但在客车承载着大量运输工作的同时,人们对客车的安全性能重视程度也在逐渐提高。由于客车的骨架结构影响,其在整个客车的性能方面提升具有重要意义。     

基于布置优化的汽车蓄电池支架轻量化设计

为在节省设计开发成本的同时,实现蓄电池支架轻量化的目的,文章针对某款车型蓄电池的横向布置形式,进行布置分析及蓄电池支架结构的轻量化设计.通过更改蓄电池在纵梁上的布置位置,来简化蓄电池支架结构,满足轻量化设计要求,使蓄电池通过蓄电池支架,分别固定在左悬置和纵梁上.更改后的蓄电池支架结构整体质量减轻约25％,CAE分析结果显示,新设计的蓄电池支架结构满足设计要求.     

穿越城区连拱隧道合理施工工法研究

以重庆市沙坪坝区的站西站东路下穿道工程为依托,深入研究穿越城区连拱隧道的合理施工工法,从沉降、结构、施工、经济性等方面对比台阶法和CD法,并优化CD法的施工工序,确定对沉降变形起控制作用的施工关键工序。结果表明:修建穿越城区的连拱隧道,采用CD法引起的拱顶及地表沉降量、支护结构承受的最大拉压应力及围岩坍塌范围较台阶法大幅减少;优化后的CD法在控制沉降、结构受力、施工组织方面具有综合优势,其在施工中对地表及拱顶沉降起控制作用的关键工序对相应部位的拱顶及地表累计沉降的影响比重均达到10%以上。     

Updating of Travel Behavior Model Parameters and Estimation of Vehicle Trip Chain Based on Plate Scanning

This article proposes a maximum-likelihood method to update travel behavior model parameters and estimate vehicle trip chain based on plate scanning. The information from plate scanning consists of the vehicle passing time and sequence of scanned vehicles along a series of plate scanning locations (sensor locations installed on road network). The article adopts the hierarchical travel behavior decision model, in which the upper tier is an activity pattern generation model, and the lower tier is a destination and route choice model. The activity pattern is an individual profile of daily performed activities. To obtain reliable estimation results, the sensor location schemes for predicting trip chaining are proposed. The maximum-likelihood estimation problem based on plate scanning is formulated to update model parameters. This problem is solved by the expectation-maximization (EM) algorithm. The model and algorithm are then tested with simulated plate scanning data in a modified Sioux Falls network. The results illustrate the efficiency of the model and its potential for an application to large and complex network cases.     

锂离子电池组散热设计及送风策略

通过实验研究了锂离子电池1C倍率放电,20℃自然对流情况下的温升特性。测得了20℃环境温度下电池的充放电内阻特性,并根据某品牌18650型锂离子电池的物性参数以及实验测得的内阻数据建立了电池单体仿真模型,仿真计算了与实验同工况下的温度分布情况,最大误差4.9%。设计了一种包含480节电池的并行通风空气冷却散热结构,并通过正交试验进行了优化,得到了进出风孔距电池的最小距离1mm,上挡板距离电池的最小距离1mm,下挡板距离电池的最小距离1mm的最优结构,使电池组的最大温升下降了5.71℃,最大温差降低了5.06℃。并基于最优结构给出了120s后每60s改变送风方向的往复送风策略,使电池组即使在40℃、2C放电的恶劣工况下也能够工作在25℃-40℃,电池单体温差5℃以下的工作环境中。     

统一通信平台的优化策略研究

统一通信平台为企业内部提供了可靠的语音、视频及传输功能.针对呼和浩特铁路局科研所建立的统一通信平台,对平台的可靠性、安全性、扩展性、标准化等方面提出策略和建议,以便今后的优化处理.     

Lane assignment problem using a genetic algorithm in the Automated Highway Systems

This paper deals with the lane assignment problem in the Automated Highway Systems (AHS). The purpose of lane assignment strategies is to increase throughput on multi-lane highways with many entry and exit points, based on the itineraries of vehicles using the highway (point of entry, time of entry and exit point) and the effects of maneuvers. Using partitioned lane assignment strategies, the lane assignment problem is formulated as an optimization problem to find the proper positions of partitions. Then the optimal problem is solved using a Genetic Algorithm (GA). The proposed algorithm has been validated by comparing its solution with that of an all-cases algorithm for a simple case. Moreover, a traffic simulator with a realistic car-following model as well as lane change logic has been developed. The simulation results show the efficiency of the proposed genetic algorithm, compared with random assignment algorithms.     

What are the value and implications of two-car households for the electric car?

The major barriers to a more widespread introduction of battery electric vehicles (BEVs) beyond early adopters are the limited range, charging limitations, and costly batteries. An important question is therefore where these effects can be most effectively mitigated. An optimization model is developed to estimate the potential for BEVs to replace one of the conventional cars in two-car households and to viably contribute to the households’ driving demand. It uses data from 1 to 3 months of simultaneous GPS logging of the movement patterns for both cars in 64 commuting Swedish two-car households in the Gothenburg region.The results show that, for home charging only, a flexible vehicle use strategy can considerably increase BEV driving and nearly eliminate the unfulfilled driving in the household due to the range and charging limitations with a small battery. The present value of this flexibility is estimated to be on average $6000–$7000 but varies considerably between households. With possible near-future prices for BEVs based on mass production cost estimates, this flexibility makes the total cost of ownership (TCO) for a BEV advantageous in almost all the investigated households compared to a conventional vehicle or a hybrid electric vehicle. Because of the ubiquity of multi-car households in developed economies, these families could be ideal candidates for the initial efforts to enhance BEV adoptions beyond the early adopters. The results of this research can inform the design and marketing of cheaper BEVs with small but enough range and contribute to increased knowledge and awareness of the suitability of BEVs in such households.     

The flight perturbation problem

Airlines spend considerable time, effort and financial resources on planning. It is essential to create a competitive timetable and construct a fleet and a crew schedule that utilizes these resources to the maximum. Unfortunately, it is all too common that an airline is faced with the necessity of reconstructing their schedules due to some unforeseen event, for example an aircraft breakdown or a crew member that is indisposed. In this paper, an application that can help airlines solve the complex problem of reconstructing aircraft schedules is presented. A mixed integer multicommodity flow model with side constraints is developed and further reformulated into a set packing model using the Dantzig—Wolfe decomposition. Cancellations, delays and aircraft swaps are used to resolve the perturbation, and the model ensures that the schedule returns to normal within a certain time. Two column generation schemes for heuristically solving the model are tested on real problem data obtained from a Swedish domestic airline. The computational tests show that the application is capable of presenting high quality solutions in a few seconds and therefore can be used as a dynamic decision support tool by the airlines.