Energy-aware control for automated container terminals using integrated flow shop scheduling and optimal control

The performance of container terminals needs to be improved to handle the growth of transported containers and maintain port sustainability. This paper provides a methodology for improving the handling capacity of an automated container terminal in an energy-efficient way. The behavior of a container terminal is considered as consisting of a higher level and a lower level represented by discrete-event dynamics and continuous-time dynamics, respectively. These dynamics represent the behavior of a large number of terminal equipment. The dynamics need to be controlled. For controlling the higher level dynamics, a minimal makespan problem is solved. For this, the minimal time required by equipment for performing an operation at the lower level is needed. The minimal time for performing an operation at the lower level is obtained using Pontryagin’s Minimum Principle. The actual operation time allowed by the higher level for processing an operation at the lower level is subsequently determined by a scheduling algorithm at the higher level. Given an actual operation time, the lower level dynamics are controlled using optimal control to achieve minimal energy consumption while respecting the time constraint. Simulation studies illustrate how energy-efficient management of equipment for the minimal makespan could be obtained using the proposed methodology.     

The impact of a congestion pricing exemption on the demand for new energy efficient vehicles in Stockholm

As governments seek to transition to more efficient vehicle fleets, one strategy has been to incentivize ‘green’ vehicle choice by exempting some of these vehicles from road user charges. As an example, to stimulate sales of energy efficient vehicles (EEVs) in Sweden, some of these automobiles were exempted from Stockholm’s congestion tax. In this paper the effect this policy had on the demand for new, privately-owned, exempt EEVs is assessed by first estimating a model of vehicle choice and then by applying this model to simulate vehicle alternative market shares under different policy scenarios. The database used to calibrate the model includes owner-specific demographics merged with vehicle registry data for all new private vehicles registered in Stockholm County during 2008. Characteristics of individuals with a higher propensity to purchase an exempt EEV were identified. The most significant factors included intra-cordon residency (positive), distance from home to the CBD (negative), and commuting across the cordon (positive). By calculating vehicle shares from the vehicle choice model and then comparing these estimates to a simulated scenario where the congestion tax exemption was inactive, the exemption was estimated to have substantially increased the share of newly purchased, private, exempt EEVs in Stockholm by 1.8% (±0.3%; 95% C.I.) to a total share of 18.8%. This amounts to an estimated 10.7% increase in private, exempt EEV purchases during 2008, i.e., 519 privately owned, exempt EEVs.     

Biofuel futures in road transport – A modeling analysis for Sweden

First and second generation biofuels are among few low-carbon alternatives for road transport that currently are commercially available or in an early commercialization phase. They are thus potential options for meeting climate targets in the medium term. For the case of Sweden, we investigate cost-efficient use of biofuels in road transport under system-wide CO₂ reduction targets to 2050, and the effects of implementation of targets for an almost fossil-free road transport sector to 2030. We apply the bottom-up, optimization MARKAL_Sweden model, which covers the entire Swedish energy system including the transport sector. For CO₂ reductions of 80% to 2050 in the Swedish energy system as a whole, the results of the main scenario show an annual growth rate for road transport biofuels of about 6% from 2010 to 2050, with biofuels accounting for 78% of road transport final energy use in 2050. The preferred biofuel choices are methanol and biomethane. When introducing additional fossil fuel phase-out policies in road transport (−80% to 2030), a doubling of the growth rate to 2030 is required and system CO₂ abatement costs increases by 6% for the main scenario. Results imply that second generation biofuels, along with energy-efficient vehicle technologies such as plug-in hybrids, can be an important part of optimized system solutions meeting stringent medium-term climate targets.     

对2006版《铁路线路修理规则》中有关曲线技术标准问题的探讨

曲线技术标准问题是当前主要干线提速的一个关键问题,本文就2006年10月1日开始执行的新版《铁路线路修理规则》对原《铁路线路维修规则》中有关曲线的技术标准修改情况,结合提速工作实践,从技术标准的修订角度以及执行角度进行了探讨。     

基于检修资源共享的现代有轨电车车辆基地规模测算及关键指标分析

结合相关城市在有轨电车车辆基地建设方面的经验,对现代有轨电车车辆基地规划关键性指标进行量化分析。针对城市土地资源紧张的特点,提出有轨电车规划中的资源共享理念,在网络阶段采用"集中检修分散停车"的规划方法。给出了车辆基地规模测算方法:按检修台位测算以及按有轨电车车辆停放规模测算,并将该理念与方法应用于深圳市龙华新区现代有轨电车线网实际案例中。结果表明,该方法在有轨电车车辆基地的选址规划,城市土地的集约利用,优化检修资源配置方面具有重要意义,可为城市交通相关规划和运营部门决策提供参考。     

铁路客车检修企业ERP管理信息系统的开发与实现

以铁路客车检修企业成功实现信息化管理为典型样例,分析了铁路客车检修企业的业务流程,阐述了ERP管理信息系统的设计架构、系统功能,论述了关键技术的应用,描述了系统在实际企业中的具体实现.     

高速公路服务区生活污水特征及其处理工艺研究进展

聚焦于我国高速公路服务区的生活污水,由于服务区车辆随机性大,从而污水具有水量、水质变化波动大的特征,并将其与常规生活污水作对比,可以得出高速公路服务区污水浓度更高,成分更复杂,处理难度更大。针对此污水详细介绍了目前普遍采用的四种组合工艺,分别是生物接触氧化法+沉淀工艺、AO+MBR工艺、生物预处理+人工湿地、生物滤池工艺,并对四种工艺从处理效果、建设成本、运行成本、可操作性以及不同工艺的缺点上进行了比较分析。最后文章针对污水资源化利用的可行性,从水质和经济上进行了分析,将中水回用于绿化、冲厕等用途是高速公路服务区污水资源化利用的有效途径,不仅保护周围环境,节约服务区运营成本,同时可实现经济和环境效益。     

The Pollution-Routing Problem

The amount of pollution emitted by a vehicle depends on its load and speed, among other factors. This paper presents the Pollution-Routing Problem (PRP), an extension of the classical Vehicle Routing Problem (VRP) with a broader and more comprehensive objective function that accounts not just for the travel distance, but also for the amount of greenhouse emissions, fuel, travel times and their costs. Mathematical models are described for the PRP with or without time windows and computational experiments are performed on realistic instances. The paper sheds light on the tradeoffs between various parameters such as vehicle load, speed and total cost, and offers insight on economies of ‘environmental-friendly’ vehicle routing. The results suggest that, contrary to the VRP, the PRP is significantly more difficult to solve to optimality but has the potential of yielding savings in total cost.     

滨海新区软土路基沉降曲线拟合分析

软土路基沉降问题是软土地区公路工程建设中面临的技术难题之一。分析双曲线法、指数法、三点法、对数法对于拟合天津滨海新区软土路基桥头段采用加固土桩及预压处理时沉降数据的误差,并且比较分析双曲线法拟合和理正计算的预压期沉降。分析结果表明:对于滨海新区软土路基上的加固土桩+预压处理路段,双曲线比其余的曲线拟合方法精度高。     

水下近场爆破安全控制

结合大连新港地区新建15#,16#泊位工程桥墩基槽炸礁的实际情况,介绍水下近场爆破安全控制管理问题。