基于粒子群算法的粘性土主动土压力计算方法

假定挡土墙后滑动面为库伦平面滑裂面,基于能量法,推导出了适合与砂性土与粘性土的主动土压力计算公式,然后引入粒子群智能优化算法,对最危险滑动面所对应的破裂角在变量范围内进行全局搜索。运用本文方法分别对墙后填土为为砂性土和粘性土的挡土墙土压力进行计算,发现对于砂性土,优化方法得到的破裂角与理论精确解完全一致;对于粘性土,方法计算结果与实测结果相对误差为5.5%。     

AC一25C沥青混合料级配正交优化试验研究

考虑南方湿热地区沥青路面的使用要求,选取了19mm、9．5mm、4．75mm、2．36mm和0．075mm筛孔的通过率和油石比六种因素及相应的五个水平,采用正交表试验表L25（5^6）进行了优化试验,通过极差分析法和趋势图分析了各因素和各水平对各马歇尔指标的影响程度和规律,分析提出了满足各沥青混合料指标要求的AC-25C沥青混合料的矿料级配和油石比范围。     

摩托车发动机凸轮测量测点布局优化设计方法

凸轮测量的目的不同,对测点间距的要求也不同;为了最大限度地减少测量工作量,把测量误差控制在允许范围之内,必须按公差要求进行凸轮测点布局;在实际测量中,应把计算出的测点间距间的角度值圆整为整数度;无论是用平面测头还是滚柱测头测量,按本文方法算出的测点间距与测量误差的平方根成正比,而与被测点的曲率半径的平方根成反比。     

Towards data-driven car-following models

Car following models have been studied with many diverse approaches for decades. Nowadays, technological advances have significantly improved our traffic data collection capabilities. Conventional car following models rely on mathematical formulas and are derived from traffic flow theory; a property that often makes them more restrictive. On the other hand, data-driven approaches are more flexible and allow the incorporation of additional information to the model; however, they may not provide as much insight into traffic flow theory as the traditional models. In this research, an innovative methodological framework based on a data-driven approach is proposed for the estimation of car-following models, suitable for incorporation into microscopic traffic simulation models. An existing technique, i.e. locally weighted regression (loess), is defined through an optimization problem and is employed in a novel way. The proposed methodology is demonstrated using data collected from a sequence of instrumented vehicles in Naples, Italy. Gipps’ model, one of the most extensively used car-following models, is calibrated against the same data and used as a reference benchmark. Optimization issues are raised in both cases. The obtained results suggest that data-driven car-following models could be a promising research direction.     

Wheat interchanges in Europe: Transport optimization reduces emissions

Numerous Life Cycle Analysis of bread pointed out that wheat production and transportation have important impacts on the environment. But wheat is grown all around the world and it is not always consumed where it is produced. In this paper an analysis of the wheat movements around Europe is done, taking special attention on the Spanish situation. An optimization of wheat exchanges is done eliminating the import–export overlapping. This optimization entails a reduction of the number of trips by 34% and the CO₂ emissions reduction due to transportation is calculated to be 121.175 tones. Consequently less trips, fewer trucks, less traffic and lower emissions that brings economic, social and environmental benefits.     

Optimal development of alternative fuel station networks considering node capacity restrictions

A potential solution to reduce greenhouse gas (GHG) emissions in the transport sector is the use of alternative fuel vehicles (AFV). As global GHG emission standards have been in place for passenger cars for several years, infrastructure modelling for new AFV is an established topic. However, as the regulatory focus shifts towards heavy-duty vehicles (HDV), the market diffusion of AFV-HDV will increase as will planning the relevant AFV infrastructure for HDV. Existing modelling approaches need to be adapted, because the energy demand per individual refill increases significantly for HDV and there are regulatory as well as technical limitations for alternative fuel station (AFS) capacities at the same time. While the current research takes capacity restrictions for single stations into account, capacity limits for locations (i.e. nodes) – the places where refuelling stations are built such as highway entries, exits or intersections – are not yet considered. We extend existing models in this respect and introduce an optimal development for AFS considering (station) location capacity restrictions. The proposed method is applied to a case study of a potential fuel cell heavy-duty vehicle AFS network. We find that the location capacity limit has a major impact on the number of stations required, station utilization and station portfolio variety.     

基于混沌蚁群算法的最短路径选择研究

如何解决最短路径选择问题一直是城市交通流诱导系统的关键之一.基于群体仿生理论的蚁群算法是解决此问题的一种方法,针对采用蚁群算法进行最短路径选择时易出现的陷入局部最优解问题,引入混沌理论,采用混沌蚁群算法利用混沌初始化进行改善个体质量和利用混沌扰动避免在蚁群算法搜索过程中陷入局部极值,同时降低了蚁群算法的时间复杂度,从而更好的解决了最短路径选择问题.     

C2/C3等级转换设置方案优化探讨

根据列车运行控制系统C2/C3等级转换的相关规范、RBC和ATP设备C2/C3级间转换时的处理过程,对工程实施过程中存在的C2/C3级间转换设置问题进行了分析研究,并提出相应的优化措施。     

地铁架空刚性接触网平面设计软件的优化

当前地铁设计任务的不断增加对接触网辅助设计软件提出更高的要求。介绍架空刚性接触网平面设计软件的优化内容,采用先进的编程语言实现分布式软件架构,对架空刚性接触网平面设计中的底图处理、锚段智能划分、悬挂点智能布置及冲突检测和调整、拉出值自动计算、汇流排和渡线设计、工程量统计及图幅处理等算法进行优化设计。实际应用表明,本软件提高了地铁架空刚性接触网平面设计的成图质量及设计效率,可满足高质、高效的出图需求。     

多车多件货物装载布局优化模型与算法

以多车多件货物装载布局方案为研究对象,建立以标记载重量和有效容积综合利用率最大为目标函数,以货物合重心不超过容许偏移量、各件货物摆放位置不重合、货物不超出承载车辆边界、车辆承载货物总重量不超过车辆标记载重最,车辆承载货物总体积不超过车辆有效容积、货物不被重复装载等为主要约束条件的多车多件货物装载布局优化模型.设计以类First Fit划分算法和重容比为基础的模型求解算法,以制定货物装载布局方案.实例表明:用所提出的模型和算法能快速获得车辆利用效果良好、货物装载布局合理的装载布局方案.