自然灾害应急物流配送网络优化分析研究

介绍了自然灾害应急物流配送网络的相关概念及优化理论,在此基础上结合实例建立了优化自然灾害应急物流配送网络的数学模型,以时间作为模型的目标函数,分析模型的求解策略,并运用LINGO对该数学模型求解,得出了某一配送网络的最优配送路线,使得总配送时间消耗最少。     

大跨度斜拉桥索塔锚固区应力分析

斜拉桥拉索锚固区是索塔受力的关键部位,在斜拉索大吨位拉力及预应力共同作用下,受力十分复杂,保证其结构安全、受力合理是斜拉桥建造过程中的关键问题.运用实体有限元方法对某斜拉桥索塔锚固区进行空间应力分析,对比分析了3种不同工况下锚固区的受力特点及应力分布规律.分析结果表明,采用环向井字形的水平预应力束配置形式是合理的;在1 265 MPa的张拉控制应力下,各铜束应力都已经相当接近1 116 MPa,说明了预应力钢束的强度已经充分发挥,不宜再提高张拉控制力.     

Hypercatadioptric line images for 3D orientation and image rectification

In central catadioptric systems 3D lines are projected into conics. In this paper we present a new approach to extract conics in the raw catadioptric image, which correspond to projected straight lines in the scene. Using the internal calibration and two image points we are able to compute analytically these conics which we name hypercatadioptric line images. We obtain the error propagation from the image points to the 3D line projection in function of the calibration parameters. We also perform an exhaustive analysis on the elements that can affect the conic extraction accuracy. Besides that, we exploit the presence of parallel lines in man-made environments to compute the dominant vanishing points (VPs) in the omnidirectional image. In order to obtain the intersection of two of these conics we analyze the self-polar triangle common to this pair. With the information contained in the vanishing points we are able to obtain the 3D orientation of the catadioptric system. This method can be used either in a vertical stabilization system required by autonomous navigation or to rectify images required in applications where the vertical orientation of the catadioptric system is assumed. We use synthetic and real images to test the proposed method. We evaluate the 3D orientation accuracy with a ground truth given by a goniometer and with an inertial measurement unit (IMU). We also test our approach performing vertical and full rectifications in sequences of real images.     

基于仿真方法的任务集可调度性判定工具

针对含有纯周期任务的任务集可调度性判定问题,提出一种基于仿真方法的任务集可调度性判定工具。通过设定时钟变量,模拟任务调度过程中的系统时钟,在时钟变量值增长的过程中,根据任务优先级从高到低的顺序,分析各个任务的截止时间限,判定任务集的可调度性。实例分析证明了该工具的可调度性判定结果正确。     

基于CTBN的移动对象不确定轨迹预测算法

为了高效准确地预测移动对象动态运动轨迹,提出了一种基于轨迹时间连续贝叶斯网络(CTBN)的不确定性轨迹预测算法,充分考虑了移动速度和方向对移动对象动态运动行为的影响,包含3个主要步骤:热点区域挖掘将轨迹数据集划分为不同的热点聚簇;轨迹时间连续贝叶斯网络的构建,其由3个变量(街区号、移动速度、移动方向)构成的状态组合;利用该网络预测移动对象动态运动行为计算可能运动轨迹。不同数据集上的实验结果表明该算法的预测精度优于朴素预测算法,并证明了热点区域挖掘的作用在于能够在保证较高预测准确性的前提下提高预测时间性能近60%。     

轴向运动粘弹性夹层板动态分叉与混沌行为

基于轴向运动粘弹性夹层板横向振动非线性动力学模型,采用二阶Galerkin截断将非线性动力学模型转化为非线性微分方程,最后利用相图、庞加莱映射、功率谱图和分叉图等方法研究了粘弹性夹层板随轴向运动速度变化出现的周期运动、拟周期运动和混沌现象。     

基于流量耦合分析的先出后入型快速路进出口方案设计

为确定先出后入型快速路进出口设计方案,考虑不同车流密度对通行能力计算模型的影响,计算不同的进出口车流条件下,快速路主路最外侧车道通行能力,通过对其分析比较以获取最佳快速路进出口设计方案,解决了目前的设计方案缺乏与流量耦合分析的问题。计算结果表明:当Q出<509pcu/h且Q入<509pcu/h时,采用出口道无减速车道-入口道无加速车道方案;当509pcu/h≤Q出<589pcu/h且509pcu/h≤Q入<589pcu/h时,采用出口道无减速车道-入口道设加速车道设计方案;当Q出≥589pcu/h且Q入≥589pcu/h时,采用出口道设减速车道-入口道设加速车道方案。     

影响岩质路堑边坡表层土稳定性因素的敏感度分析

针对渝怀铁路鱼嘴车站岩质路堑植被边坡,采用直剪切试验获得边坡表层绿色防护层的物理力学参数。在此基础上,选取5个影响边坡表层土稳定性的因素(坡度、土层厚度、重度、粘聚力、内摩擦角),采用数学及数理统计的方法进行敏感度分析,得出各影响因素的敏感度顺序为内摩擦角>坡度>重度>土层厚度>粘聚力,分析表明绿色防护层的内摩擦角是控制其稳定性的主控因素。     

建基面岩体表层低波速带分布特征及其成因

坝基开挖后,表层岩体会产生松弛卸荷现象,引起表层岩体声波波速明显降低,在表层形成低波速带。某水电站坝基左岸表层低波速带空间分布特征分析结果表明:坝基岩体表层低波速带的空间分布呈层状,局部出现异常深度;坝基表层低波速带在空间上的分布状况与表层岩体浅表生时效变形、建基面地质构造等因素有关。     

An agent-based genetic algorithm for hybrid flowshops with sequence dependent setup times to minimise makespan

This paper deals with a variant of flowshop scheduling, namely, the hybrid or flexible flowshop with sequence dependent setup times. This type of flowshop is frequently used in the batch production industry and helps reduce the gap between research and operational use. This scheduling problem is NP-hard and solutions for large problems are based on non-exact methods. An improved genetic algorithm (GA) based on software agent design to minimise the makespan is presented. The paper proposes using an inherent characteristic of software agents to create a new perspective in GA design. To verify the developed metaheuristic, computational experiments are conducted on a well-known benchmark problem dataset. The experimental results show that the proposed metaheuristic outperforms some of the well-known methods and the state-of-art algorithms on the same benchmark problem dataset.