收费道路均衡配流的双层规划模型分析

考虑弹性用户需求下,当两点之间的收费额增加时,阻抗会随之增加,交通需求量会相应减少,引入新的交通阻抗函数。根据弹性交通需求下交通均衡配流,考虑一个双层规划模型来考虑道路经营者收费道路费率制定,同时在这个基础上给出了基于遗传一模拟退火的混合优化算法（GASA）求解算法,最后通过一个数值算例加以简单的论证,得到比较合理的费率。     

城市公共交通中的公交输送能力问题探讨

本文通过对城市交通现状的分析,指出发展城市公共交通的必要性,针对公交运行中的问题,引出了公交输送能力这一考查指标,并建立了公交输送能力模型。最后以中关村大街人民大学站为例进行了定量分析,提出如何用公交输送能力来明确公共交通中出现的问题,对研究公交线路和车辆的优化配置提供了理论依据。     

A reverse causal-effect modeling approach for signal control of an oversaturated intersection

A novel approach is presented in which signalized intersections are treated as normal highway bottlenecks for improved computational efficiency. It is unique in two ways. First, it treats the signalized intersections as common freeway bottlenecks by a reversed cause and effect modeling approach. Both traffic arrivals and departures are modeled by smooth continuous functions of time as if there were no interruptions to traffic flows from signals. The use of smooth continuous functions for departure curves instead of commonly used step functions makes it easy to apply differential calculus in optimization and future extension to a system of intersections. Second, a dynamic linear programming (LP) model is then developed to maximize the total vehicular output from the intersection during the entire period of congestion subject to prevailing capacity and other operational constraints. The continuous optimal departure flow rate (the effect) is then converted to signal timing parameters (the cause) that can be readily implemented. Two numerical examples are presented to demonstrate the properties of the proposed algorithm and examine its performance.     

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.     

Parallel Distributed Implementation of Truss Optimization on a Local Area Network

A two-level optimization method for the design of complex truss and parallel distributed implementation on a LAN is presented using parallel virtual machine (PVM) for Win 32 as message passing between PCs. The volumes of truss are minimized by decomposing the original optimization problem into a number of bar optimization problems executed concurrently and a coordinate optimization problem, subject to constraints on nodal displacements, and stresses, buckling and crippling of bars, etc. The system sensitivity analysis that derives the partial derivatives of displacements and stresses with respect to areas are also performed in parallel so as to shorten the analysis time. The convergence and the speedup performances as well as parallel computing efficiency of the method are investigated by the optimization examples of a 52-bar planar truss and a 3 126-bar three-diraensional truss. The results show that the ideal speedup is obtained in the cases of 2 PCs for the 3 126-bar space truss optimization, while no speedup is observed for the 52-bar truss. It is concluded that (1) the parallel distributed algorithm proposed is efficient on the PC-based LAN for the coarsegrained large optimization problem; (2) to get a high speedup, the problem granularity should match with the network granularity;and (3) the larger the problem size is, the higher the parallel efficiency is.     

船体结构耐撞性优化设计方法研究

提出了一种船体结构耐撞性设计的优化方法,它是在试验设计、径向基神经网络和遗传算法的基础上发展而成的,用高精度的快速分析模块来代替计算量很大的复杂模型,且能处理混合离散变量和工程约束条件。为表征船体结构的耐撞性能,本文引入了耐撞指标的概念。应用上述优化方法对某散货船舷侧结构进行了耐撞性优化设计。优化过程中以耐撞指标作为目标函数,以结构重量作为约束条件,用非线性有限元动态响应分析程序ＭＳＣ／ＤＹＴＲＡ     

汽车覆盖件冲压方向优化系统设计

通过分析影响汽车覆盖件冲压方向选择的因素,建立了以评价函数法为基础的冲压方向优化模型。利用该模型对冲压件截面形状进行了分析,确定了截面转角的公共可行域,并建立了一组目标函数作为优化对象。在公共可行域内优化各个截面的转角,然后加权平均可得到目标函数的最优值。以典型汽车覆盖件为例,对实现覆盖件冲压方向的优化系统进行了理论验证。     

汽车侧面碰撞乘员约束系统的多目标优化

针对某轿车建立了基于多刚体理论的侧面碰撞乘员约束系统动态仿真模型,并依据试验结果进行了模型的有效性验证。通过对乘员侧面碰撞伤害指标的分析,提出了包含乘员多输出目标值的综合伤害评估值,并应用试验设计方法,以所提出的综合伤害评估值为目标进行了该车的侧面碰撞乘员约束系统多参数优化,给出了符合实际的优化结果。     

基于蚁群算法的AUV动目标避碰规划的方法研究

提出了基于蚁群算法(ACA)实现AUV对运动目标避碰规划的方法.该方法把避碰、路径最短和航迹跟踪等约束条件映射为目标函数,使得路径搜索过程快速高效.计算机仿真表明:该方法使AUV能够较好地实现对运动目标的避碰;由此说明此项研究具有一定的可行性和有效性.     

Mechanical Analysis of the Down-Hole String in a Deep Well

In a deep well, under high pressure and temperature, the force, deformation, and movement of the downhole string are very complicated. In this paper, based on the analysis of the working environment and load properties of the down-hole string in deep wells, the factors of high temperature, high pressure, and the complex structure of wells have been taken into consideration. The loads of the down-hole string, stability, back buckle configuration, dynamic characteristics, mechanical strength, and deformation have been systematically studied. On this basis, mechanical models of a down-hole string under different conditions have been established and software for aiding analysis has been developed. By using this software, deep well strings under different construction parameters can be simulated and analyzed, providing a theoretical basis and method for down-hole string assembly, as well as string down-hole construction and operation.