无底价招标--降低地铁工程造价的有效措施

对地铁建设招标评标办法做进一步思考,分析传统的政府定额方式确定工程招标标底评标的利弊,探讨与论证市场化的“无底价招标法”在地铁建设中的运用和发展;指出无底价招标法可维护招标工作的公开、公正和公平的基本原则,能够取得经济效益和社会效益的最大化。     

Design of robust-stable and quadratic finite-horizon optimal controllers with low trajectory sensitivity for uncertain active suspension systems

This paper presents a design method for designing the robust-stable and quadratic-finite-horizon-optimal controllers of uncertain active suspension systems. The method integrates a robust stabilisability condition, the orthogonal functions approach (OFA) and the hybrid Taguchi-genetic algorithm (HTGA). Using the integrative computational method, a robust-stable and quadratic-finite-horizon-optimal controller with low-trajectory sensitivity can be obtained such that (i) the active suspension system with elemental parametric uncertainties is stabilised and (ii) a quadratic-finite-horizon-integral performance index including a quadratic trajectory sensitivity term for the nominal active suspension system is minimised. The robust stabilisability condition is proposed in terms of linear matrix inequalities (LMIs). Based on the OFA, an algebraic algorithm only involving the algebraic computation is derived for solving the nominal active suspension feedback dynamic equations. By using the OFA and the LMI-based robust stabilisability condition, the dynamic optimisation problem for the robust-stable and quadratic-finite-horizon-optimal controller design of the linear uncertain active suspension system is transformed into a static-constrained-optimisation problem represented by the algebraic equations with constraint of LMI-based robust stabilisability condition; thus greatly simplifies the design problem. Then, for the static-constrained-optimisation problem, the HTGA is employed to find the robust-stable and quadratic-finite-horizon-optimal controllers of the linear uncertain active suspension systems. A design example is given to demonstrate the applicability of the proposed integrative computational approach.     

Prediction of the interaction between a simple moving vehicle and an infinite periodically supported rail – Green's functions approach

This paper herein describes the interaction between a simple moving vehicle and an infinite periodically supported rail, in order to signalise the basic features of the vehicle/track vibration behaviour in general, and wheel/rail vibration, in particular. The rail is modelled as an infinite Timoshenko beam resting on semi-sleepers via three-directional rail pads and ballast. The time-domain analysis was performed applying Green's matrix of the track method. This method allows taking into account the nonlinearities of the wheel/rail contact and the Doppler effect. The numerical analysis is dedicated to the wheel/rail response due to two types of excitation: the steady-state interaction and rail irregularities. The study points out to certain aspects regarding the parametric resonance, the amplitude-modulated vibration due to corrugation and the Doppler effect.     

浅谈运用代建制进行工程项目管理

国务院《关于投资体制改革的决定》明确提出对非经营性政府投资项目加快推行“代建制”,这是政府投资的建设工程领域一种新兴的工程管理方式。该文阐述了工程项目管理代建制在我国的起源、发展及其性质,通过对政府投资的分析,论述了实行代建制的意义,并详细介绍了代建制的合同文件、奖惩及取费。     

城市公共交通服务供给侧政府管理职责 边界与市场机制研究

为厘清政府在公共交通服务供给侧的管理职责边界,进一步发挥市场机制的作用,提高公 共交通资源配置效率,在对目前公共交通服务供给侧政府管理和市场机制主要误区进行分析的基 础上,对公共交通服务进行科学分类,细分为基本公共交通服务和多元化公共交通服务,明确了 各自的服务定位和特征,并应用四象限法则,以“政府主导”和“市场积极性”为重要因素,分 析不同类型公共交通服务供给侧方面政府和市场发挥的作用和参与方式,最后,研究提出基本公 共交通服务和多元化公共交通服务中政府应当承担的管理职责,以及市场机制参与提供公共交通 服务的主要切入点和制度保障。     

基于MATLAB的遗传算法优化软件设计

优化设计理论使工程设计方法发生了变革。其中,遗传算法理论与传统优化算法相比,具有鲁棒性、自适应性、全局优化性和隐含并行性的特点。本文基于Matlab语言编程实现了遗传算法,并设计搭建了用户界面。通过标准测试函数对所开发软件优化功能进行了测试检验,优化结果准确,操作简单方便,系统设计满足预期要求。     

生产执行系统在样车试制过程中的应用

随着信息技术与工业化的进一步融合,制造业的发展也面临着新的契机,“质量”逐渐在品牌建设和市场中占据着越来越重要的位置。在样车试制的过程中,生产执行系统的建设和使用能够有效提升样车的质量,这对我国汽车制造业自主技术创新水平的提升有着非常重要的促进性作用。基于此,文章将对生产执行系统的基本架构和主要功能进行介绍,最后,以试制信息管理系统为例,对生产执行系统在样车试制中的应用进行简单分析。     

建设福建省专用车辆产品质量检验中心的必要性

龙岩市是福建省最早的汽车工业基地.全省第一台农用拖拉机在龙岩生产制造.这为龙岩市打下了很好的汽车工业基础.特别是在2000年以后,依托老龙马的工业基础,加之政府引导的龙岩汽车工业的转型升级,快速发展了如龙马环卫、畅丰专汽、海德馨、侨龙等为主的一批极具特色的专用车企业.本文将结合龙岩市的专用车产业发展现状、政府政策导向、...     

确定模糊控制最少推理规则数量的原则

提出在柴油机控制系统模糊规则的设计中 ,确定最少模糊推理规则的原则 ,指出在论域为正负偏差时 ,最小隶属函数个数是 3时仍可满足控制精度要求 ;并建立了柴油机模糊PID控制器的三维模糊数学模型 ,该模型被用于一个 4输入 3输出 (4I3O)柴油机模糊控制器的设计中。     

Generating complete all-day activity plans with genetic algorithms

Activity-based demand generation contructs complete all-day activity plans for each member of a population, and derives transportation demand from the fact that consecutive activities at different locations need to be connected by travel. Besides many other advantages, activity-based demand generation also fits well into the paradigm of multi-agent simulation, where each traveler is kept as an individual throughout the whole modeling process. In this paper, we present a new approach to the problem, which uses genetic algorithms (GA). Our GA keeps, for each member of the population, several instances of possible all-day activity plans in memory. Those plans are modified by mutation and crossover, while bad instances are eventually discarded. Any GA needs a fitness function to evaluate the performance of each instance. For all-day activity plans, it makes sense to use a utility function to obtain such a fitness. In consequence, a significant part of the paper is spent discussing such a utility function. In addition, the paper shows the performance of the algorithm to a few selected problems, including very busy and rather non-busy days.