Synchronous hybrid transport network design

Delay,as an inevitable real-world phenomenon,is usually ignored in transport network design.A model of urban hybrid transport system with stochastic delay was created on the basis of the idealized public transport system design.After formulating the total trip time cost composed of accessing time in the sub-region of the city,waiting time at the public transport station,and in-vehicle time in the public transit network,the analytical properties of the total trip time cost function were investigated.The results show that in the urban hybrid transport network design,the total trip time cost reaches its approximate minimum in a δ-neighbourhood of buffer time of 1.5 min,and that through modelling optimal delay in hybrid transport system,the maximal synchronization can be achieved and operational efficiency and passenger satisfaction can be improved.The proposed modelling and analytical investigations are attempts to contribute to more realistic modelling of future idealized public transport system that involves more practical constraints.

Intermodal Freight Network Design for Transport of Perishable Products

The amount of perishable products transported via the existing intermodal freight networks has significantly increased over the last years. Perishable products tend to decay due to a wide range of external factors. Supply chain operations mismanagement causes waste of substantial volumes of perishable products every year. The heretofore proposed mathematical models optimize certain supply chain processes and reduce decay of perishable products, but primarily deal with local production, inventory, distribution, and retailing of perishable products. However, significant quantities of perishable products are delivered from different continents, which shall increase the total transportation time and decay potential of perishable products as compared to local deliveries. This paper proposes a novel optimization model to design the intermodal freight network for both local and long-haul deliveries of perishable products. The objective of the model aims to minimize the total cost associated with transportation and decay of perishable products. A set of piecewise approximations are applied to linearize the non-linear decay function for each perishable product type. CPLEX is used to solve the problem. Comprehensive numerical experiments are conducted using the intermodal freight network for import of the seafood perishable products to the United States to draw important managerial insights. Results demonstrate that increasing product decay cost may significantly change the design of intermodal freight network for transport of perishable products, cause modal shifts and affect the total transportation time and associated costs.

A Design of Information Teaching in Container Transport

The teaching design is based on the task of "Container Transport" in the course of"English for International Shipping Business", aiming to discuss Design of information teaching in Business English Class. MOSO TEACH, CFNET platform,Cartoon have been applied in the design. Informationalized teaching has brought the vividness and dramatic effect to the knowledgebased class.

Differences in transportation and leisure physical activity by neighborhood design controlling for residential choice

Background:Cross-sectional studies provide useful insight about the associations between the built environment and physical activity(PA),particularly when reasons for neighborhood choice are considered.Our study analyzed the relationship between levels of weekly transportation and leisure PA among 3 neighborhood designs,statistically adjusting for sociodemographic characteristics and reasons for neighborhood choice.Methods:A stratified random sample of adults(age>20 years)living in Calgary(Canada)neighborhoods with different neighborhood designs(grid,warped-grid,and curvilinear)and socioeconomic status completed a self-administered questionnaire capturing PA,sociodemographic characteristics,and reasons for neighborhood choice(response rate=10.1%;n=1023).Generalized linear models estimated associations between neighborhood design and transportation and leisure PA outcomes(participation(any vs.none)and volume(metabolic equivalent:h/week)),adjusting for neighborhood socioeconomic status,sociodemographic characteristics(gender,age,ethnicity,education,household income,marital status,children,vehicle access,dog ownership,and injury),and reasons for neighborhood choice(e.g.,proximity and quality of recreational and utilitarian destinations,proximity to work,highway access,aesthetics,and sense of community).Results:Overall,854 participants had resided in their neighborhood for at least 12 months and provided complete data.Compared with those living in curvilinear neighborhoods,grid neighborhood participants had greater odds(p<0.05)of participating in any transportation walking(odds ratio(OR)=2.17),transportation and leisure cycling(OR=2.39 and OR=1.70),active transportation(OR=2.16),and high-intensity leisure PA(≥6 metabolic equivalent;OR=1.74),respectively.There were no neighborhood differences in the volume of any transportation or leisure PA undertaken.Adjustment for neighborhood selection had minimal impact on the statistical or practical importance of model estimates.Conclusion:Neighborhood design is associated with PA patterns in adults,independent of reasons for neighborhood choice and sociodemogranhic factors.

An overview of seismic ground motion design criteria for transportation infrastructures in USA

This paper provides an overview of current seismic ground motion criteria for transportation infrastructures in USA. This is to facilitate an understanding of current seismic performance levels and design practices in USA for transportation professionals world-wide, especially those in Asian and Pacific regions. Seismic vulnerability of a transportation infrastructure is determined by the risk associated with the seismic ground motion and specified performance criteria. Determining an acceptable seismic risk is a very complex task that must consider both social and economic aspects. Obviously, the amount of risk that a railway bridge can accept may be different from that of a highway bridge. The economic tolerance in one country may be different from that in another country for the same type of infrastructure. In this paper, seismic performance levels and design criteria of ground motion for highway bridges, railway bridges and ports＇ container wharves in USA are reviewed, and design examples are presented to demonstrate how to develop the code-based and site-specific design acceleration response spectra and time histories.

Feasibility neutronic design for the reactor core configurations of a 5 MWth transportable block-type HTR

Small long-life transportable high temperature gas-cooled reactors(HTRs) are interesting because they can safely provide electricity or heat in remote areas or to industrial users in developed or developing countries.This paper presents the neutronic design of the U-Battery,which is a 5 MWth block-type HTR with a fuel lifetime of 5–10 years.Assuming a reactor pressure vessel diameter of less than 3.7 m,some possible reactor core configurations of the 5 MWth U-Battery have been investigated using the TRITON module in SCALE 6.The neutronic analysis shows that Layout 12×2B,a scattering core containing 2 layers of 12 fuel blocks each with 20% enriched235U,reaches a fuel lifetime of 10 effective full power years(EFPYs).When the diameter of the reactor pressure vessel is reduced to 1.8 m,a fuel lifetime of 4 EFPYs will be achieved for the 5 MWth U-Battery with a 25-cm thick graphite side reflector.Layouts 6×3 and 6×4 with a 25-cm thick BeO side reflector achieve a fuel lifetime of 7 and 10 EFPYs,respectively.The comparison of the different core configurations shows that,keeping the number of fuel blocks in the reactor core constant,the annular and scattering core configurations have longer fuel lifetimes and lower fuel cost than the cylindrical ones.Moreover,for the 5 MWth U-Battery,reducing the fuel inventory in the reactor core by decreasing the diameter of fuel kernels and packing fraction of TRISO particles is more effective to lower the fuel cost than decreasing the 235U enrichment.

纯氢与掺氢天然气管道摩阻系数预测

纯氢与掺氢天然气管道是实现氢气长距离、大规模输送的最佳方式之一,其中摩阻系数是气体管道水力计算的关键参数,现有的经验公式不能满足预测掺氢天然气的摩阻系数要求。为改进传统的摩阻系数计算公式在纯氢与掺氢天然气管道系统的适用性,搭建了纯氢和掺氢天然气管输调压综合实验平台,开展纯氢和不同比例的掺氢天然气管输流动实验,根据实验采集的流量、温度、压力和管道的长度、管径等参数计算管道的摩阻系数,同时建立了摩阻系数与雷诺数、粗糙度之间的关系,并修正了传统摩阻系数公式,最后利用湖南省巴陵—长岭纯氢气管道的实际运行数据进行了验证。研究结果表明:①由于氢气与天然气物性差异较大,掺氢比会影响流动摩阻系数,相同条件下掺氢比越大摩阻系数越小;②传统摩阻系数计算公式存在30%左右的误差,创新提出的适用于纯氢和掺氢天然气的3段式摩阻系数经验公式,相对误差最大11.84%,能够有效降低误差;③与巴陵—长岭纯氢气管道实际的运行数据相比,修正后摩阻系数预测公式的平均误差为0.62%,该公式可以满足实际工程的误差要求。结论认为,得到的纯氢与掺氢天然气管道摩阻系数修正公式可应用于纯氢与掺氢天然气管道工程设计,具有重要的工程应用价值和前景。

交通工程专业设计类课程高质量教材建设刍议

在新工科建设背景下,交通工程专业设计类课程教材建设面临层级目标的设定、教材内容与标准规范的联系、知识表达形式、教材的修编再版等挑战,围绕“层级目标、专业实战、多元资源”课程教材建设目标,创新性提出了对教材内容进行从基础设计能力到创新设计能力的层级模块化编排和设计类教材核心词汇语言表达方式的教材建设思路,以实战为导向探索设计类教材知识多样化表现手法,并针对设计类课程的特点,提出教材“编写—修订—再版”全过程动态监测评估的建设技术路径。

基于有限相似方法的轴压加筋板极限强度相似缩比准则研究

在对船体结构进行相似缩比试验设计时,通常采用方向性量纲分析法。然而,传统的基于弹性理论的量纲分析法不能反映结构材料非线性过程,因而限制了其在船体结构缩比模型极限强度试验中的应用。本文基于有限相似方法,通过匹配物理空间与试验空间中的输运方程,获得结构几何尺寸、材料密度和时间的比例因子,推导得到加筋板结构缩比模型与原模型的非线性过程相似关系,分析材料参数对非线性相似过程的影响。通过开展不同缩比比例、不同材料参数的加筋板轴压极限强度数值计算,验证基于有限相似方法缩比准则的有效性。分析表明,基于有限相似方法的轴压加筋板极限强度缩比准则可以很好地体现材料的非线性特性,可以通过缩比模型结果对原模型的极限强度取得良好的预报效果。

中转点风险分级收费的危险品多式联运网络设计

近年来,危险品多式联运被广泛应用,而网络中转点由于转运量集聚,导致安全风险较高。为了有效控制危险品多式联运风险,政府可以通过中转点合理选址与分级收费,引导企业合理规划危险品运输路径。首先提出基于中转点风险分级的中转点选址与收费策略,建立危险品多式联运网络设计双层规划模型,上层为网络总风险最小化和总运输成本最小化的中转点选址与分级收费定价问题,下层为各运输事件成本最小化的运输路径规划问题。然后,使用KKT条件转换下层模型为等价约束条件,实现模型单层化,利用Gurobi求解模型。最后,通过算例表明网络风险和运输成本随着中转点数量的增加而降低,证明了中转点分级收费策略可以有效调控危险品多式联运网络风险。

Design of the Three-Dimensional Transportation System in Commercial Districts Against the Background of Urban Renewal:A Case Study of Shangbu District in Shenzhen

In this paper,Shangbu district,Shenzhen was taken for example to study the design of the three-dimensional transportation system in commercial districts against the background of urban renewal,so as to provide references for solving serious traffic problems in old urban industrial areas.Shangbu district adopted a diversified development model to ensure the appropriate spatial scale and constructed a three-dimensional transportation system concerning the underground,ground,and overground planes to guarantee the coexistence of people,goods,and vehicles.

集装箱货运网络优化问题的研究——以宁波舟山港集装箱运输为例

为优化集装箱货运网络,对进出口货运集装箱装卸中转站的最佳地理位置的选择和集装箱运输计划的设计进行了研究。2个问题同时考虑建设成本、运输成本以及存储、运力等因素,建立了一种集装箱货运网络优化模型。利用国际集装箱货运代理公司在宁波舟山港一整年的船期数据,使用LINGO软件对所建模型的效果进行求解。最终从宁波舟山港腹地现有38个存储中转仓中优选出32个中转仓存储集装箱,使大约5%的集装箱通过铁路运输,从而能节省5.74%的运营成本。

低碳视角下多式联运网络设计优化问题研究

网络设计与低碳补贴激励措施,是推进多式联运可持续发展的重要途径。基于此,从低碳视角研究水陆联运网络设计优化与补贴模式问题,考虑政府管理部门与物流用户的互动博弈行为,构建基于双层规划的水陆联运物流网络优化模型。该模型中上层规划(政府层)确定网络扩容投资决策及其补贴方案,从而最小化扩容投资与低碳补贴总成本,以及系统中碳排放量;下层模型(物流用户)则是基于广义费用的用户均衡分配模型。针对上述双层优化模型的特点,设计了基于相继平均配流算法(MSA)的改进快速非支配排序遗传算法(NSGA-Ⅱ)。以长江经济带中游地区的水陆联运物流网络为例,进行相应的实证研究,验证上述优化模型及算法的有效性;并且,在对网络进行扩容投资的情况下,对比4种补贴方案,即1)对铁路及水运弧段按固定值进行补贴;2)不进行补贴;3)不同地区的铁路及水运弧段的补贴不同;4)补贴值随机连续。研究结果表明:扩容投资可以减少网络中的超载弧段数量,同时提升网络性能;对铁路及水运弧段进行运输补贴能有效降低碳排放量;若政府关注预算限制,则倾向于按固定值补贴的方案;若更重视碳减排效果,则倾向于采取不同地区不同补贴值的方案。

基于驾驶模拟的超车仿真教学实验设计

道路交通运输专业具有多学科融合、紧密结合实践的特点,但许多交通专业课程的实践教学环节往往会受到场地大小、条件不可控、重复性差和实际道路危险性等不利因素的限制而无法顺利开展。为提升学生的实践能力与课程参与度,基于驾驶模拟技术,探讨可用于交通仿真、道路交通安全及交通行为分析等课程教学的超车仿真教学实验项目,教学实验以锻炼学生分析解决问题能力和实践操作能力为目标,详细地设计实验流程与实践教学内容,并将该实验项目在道路交通安全、交通仿真等课程的实践环节进行应用,为驾驶模拟系统在教学实验中的应用提供参考。

智能交通场景下的交互导识设计原则

目的探索智能交通场景下交互导识设计的原则,研究如何灵活应用多模态技术和交互设计方法,提升导识系统的效率和适应性,进而改善用户的出行体验。方法通过文献综述和案例分析,详细梳理和总结了交互导识设计在实际应用中的主要发展趋势、存在问题及设计师面临的挑战。结果研究显示,目前的交互导识出现了多通道应用、多终端融合,以及多样化的模式,这些变化使导识设计超越了传统静态和分散的形式,呈现出由多种维度支持的复合形态,进而要求设计师重新审视这一复杂的设计对象,调整设计原则以适应新的需求。结论提出了适用于智能交通环境下的交互导识设计原则和设计建议,包括建立更系统化的导识信息、打造一致性的用户体验和提供丰富的信息形态。

SPMT在井口平台组块滚装装船方式中的应用

针对自行式模块化运输车(Self-Propelled Modular Transporter,SPMT)滚装装船方式,以蓬莱19-3油田4腿式井口平台组块为例,在称重布置、临时支撑布置、运输抬梁布置和轴线布置等方面对SPMT装船方案进行适配性设计,在组块强度、运输抬梁强度和SPMT车板强度等方面对该方案的运输强度进行校核,并对该方案进行拓展。该方案可为后续井口平台组块装船方案设计提供参考。

景区分时预约策略下的旅游线路优化方法

为提升游客的旅游体验和景区的服务水平,探讨分时预约策略下游客游览决策行为,分析游客拥挤-调适行为对游线设计的影响及其机理.考虑游客分时预约时段选择下入园时间和游览总时间的变化、可游览景点数等约束,以游客总体拥挤感知最小、游线总体满意度最大和景点间总体走行时间最小为优化目标,构建分时预约策略下的多目标景区路线优化模型,并以颐和园为例进行实证和线路优度评价.结果表明颐和园上午预约时段(06:00—12:00)与下午预约时段(12:00—19:00)的推荐游线优度值分别为75.09、69.00,均高于颐和园推荐游线,表明优化模型精度较高.研究可为合理制定景区分时预约等客流调控措施、旅游线路优化设计、均衡景区客流的时空分布提供支撑.

高职物流管理专业课程思政教学设计——以《运输管理》课程为例

高职院校专业课程的价值应体现知识、技能传授和价值教育的一致性,强调教师进行课程教学设计时应考虑融入思想政治,使学生实现知识、技能的掌握和价值观的塑造。高职院校各专业要挖掘适合本专业的价值教育资源或职业素养,每门专业核心课程要结合课程育人目标与专业职业素养紧密衔接、一脉相承。

长途货运司机疲劳驾驶原因分析及对策

为减少长途运输中驾驶员因疲劳驾驶对个人和社会造成的严重损失,从驾驶员生理和心理两大因素、车辆和环境三个角度对货运司机疲劳驾驶原因进行分析,并针对不同问题对驾驶员开展安全教育活动、优化座椅和驾驶室设计、采取多种措施来改善长途运输的环境条件以及在货车上设置主动安全装置等提出了相应的改进对策,为以后的驾驶室设计提供了参考依据。

基于眼动数据分析交通环境要素对驾驶员视觉负荷的影响

研究旨在通过提出1种基于眼动数据得到的负荷评价指标—眼动离散程度,确定不同视觉负荷下眼动离散程度的划分阈值,并利用该指标探究交通环境要素对人工驾驶员视觉负荷影响的程度排序,进而为交通设计提供参考。研究方法为分析DADA2000数据集,利用语义分割算法与眼动特征识别算法,建立眼动离散程度变化机制模型,并将事故前3s眼动点集中区域与语义分割得到的要素进行匹配,进而得到不同视觉负荷下眼动离散程度的划分阈值和交通环境要素对驾驶员视觉负荷的影响程度排序。研究结果发现,在不同道路条件下,驾驶员的眼动离散程度和视觉负荷水平会有所变化,但事故前较短时间内眼动离散程度会降低至原来的1/3,眼动点也会集中在碰撞物或事故主要责任要素上,可通过机器学习算法对各交通环境要素影响的重要程度进行排序。分析研究结果可得到结论:利用眼动离散程度区分驾驶员视觉负荷是否过大的方法具有可行性,并可进一步用于事故防范与预测;驾驶员视觉负荷主要来源的前3位要素是自行车参与者、路侧标志杆、路面状况,影响重要度分别达到0.395、0.137、0.124。