世界干散货航运市场运量及运力分析

本文首先对国际干散货航运市场的概况进行了阐述,介绍了国际干散货航运市场特点、贸易流向以及主要航线;其次,在干散货航运市场相关数据的基础上,通过深入分析影响三大干散货航运市场的主要因素,总结出海运量的变化规律,结合现状预测各细分市场未来的需求量。并对未来几年干散货海运总需求量做出预测,对航运市场运力方面进行预测和分析。     

波罗的海贸易海运交易所运价指数介绍

1波罗的海贸易海运交易所(The Baltic Exchange)概述波罗的海交易所诞生于美国弗吉尼亚,1744年在英国伦敦将最初的“弗吉尼亚和马里兰”名称改为“弗吉尼亚和波罗的海”,经过250多年的风风雨雨,波罗的海交易所已经发展成为世界上历史最悠久、国际性自律的航运市场,专业从事海运及船舶买卖。截止到目前,全球有600多家公司成为航交所的会员,有2000多名代表在交易所为主工作。波罗的海运价指数(Baltic Freight Index,简称BFI)由伦敦航运市场每天向世界公布。它是一个综合性指数,由全球传统的12条主要干散货船航线的运价按照各自在航运市场上的重要程度和所占比重构成。它是随着波罗的海国际运     

长江干线集装箱吞吐量分析预测

港口集装箱吞吐量是进行港口规划和加强港口建设的依据,预测长江干线主要港口企业集装箱吞吐量对促进长江干线水域经济发展发挥了重要作用。以长江干线主要港口企业集装箱吞吐量为基础,分析二次指数平滑法、灰色模型预测法和BP-GA算法的原理,分别建立三种相应的预测模型并比较预测结果及精度。结果表明BP-GA模型能更加准确预测集装箱吞吐量在时间序列上的变化趋势,预测拟合度最佳。最后以该模型预测分析2021年1月至12月的长江干线主要港口企业集装箱吞吐量,为未来长江航运发展提供参考。     

曲线拟合法在煤矿矿坑涌水量预测中的应用研究

本文在广泛调查、研究、收集资料的基础上,分析矿区的工程地质、水文地质条件,研究了矿区矿坑涌水量的影响因素,采用回归分析方法中的曲线拟合方法建立各影响因素与涌水量间的数学模型,并进行涌水量预测。     

航运业哀鸿一片源于运力过剩

持续低迷的全球航运业走势令中国航运企业倍感经营压力。近日,中远等航运巨头公布的三季报业绩显示,业界原本预计的下半年航运形势有所好转的愿望并没有实现,航运业三季度业绩继续下行。第三季度中国航运信心指数仅为72.77点,首次突破景气分界线,一举跌入较为不景气区间,显示航运企业家对市场预期暗淡,后市悲观情绪弥漫,航运业前景不容乐观。     

我国高铁快运潜在市场规模预测

对我国高铁快运的潜在市场规模预测，有利于优化高铁快运服务质量，支撑高铁快运服务产品开发。以快递量作为潜在转移对象，建立向量自回归模型进行快递量预测；考虑运输安全性、便捷性、经济型、可靠性和时效性等影响因素，构建logit分担率模型进行分担率预测，得到了高铁快运市场可分担率及2020-2025年的潜在市场规模。结果表明，高铁快运市场潜在规模远大于实际市场情况，通过提高寄件服务便捷性，缩减前置等待时间，优化两端作业时间，将有利于提高高铁快运市场占有率。     

基于灰色关联度的区域公路网规模预测研究

公路网规模预测是区域公路网规划的重要内容,影响区域路网发展规模的因素既有单因素又有复合因素。本文引入熵值的概念,量化反映区域城市发展的均衡性,通过灰色关联度法,确定关联度最高的几个影响因素,建立组合模型预测公路网规模,并结合浙江省的具体情况进行实例分析。     

基于等效面积法的沥青路面预防性养护措施效果评价

本文基于安徽省高速公路路面历史性能数据,采用多元线性回归模型建立了预防性养护措施路面性能发展模型,评价了各预防性养护措施的适用性。针对实际情况采用"等效面积法"评价路面养护效益,考虑到预防性养护措施寿命较短,本文提出二次养护效益费用比的概念,对典型的预防性养护措施的实施效果进行了评价,并对影响养护效益的因素进行了分析。     

隧道变形预测的灰色与回归模型对比分析

模型预测法是目前常用的隧道围岩变形预测的方法之一。文章结合广梧高速公路茶林顶隧道工程实例，建立GM（1，1）灰色模型、GM（2，1）灰色模型和双曲函数回归模型分别对隧道围岩变形进行预测，并对各模型的预测情况进行对比分析。结果表明，不论是从短期还是从长期看，GM（1，1）灰色模型都体现了优越的模拟和预测效果，且建立预测模型时不需要大量的统计数据，可应用于工程实际。     

基于偏最小二乘回归的铁路运输收入分析研究

铁路运输收入是反映铁路运输企业盈利能力的重要指标之一,分析影响铁路运输收入的关键因素,建立计算铁路运输收入的数学模型,对提高计算速度,促进铁路运输收入增长具有重要意义。本文基于中国铁道年鉴统计数据,选取铁路营业里程、车辆数、旅客与货物的发送量、周转量等9项影响因素,采用偏最小二乘回归模型解决因素间多重相关性的问题,并与最小二乘回归模型结果进行对比。研究结果表明:运用偏最小二乘回归法计算结果精确可靠,与铁路运输收入呈正相关的主要因素为铁路货车辆数、旅客发送量以及旅客周转量,铁路客车辆数、货物周转量对铁路运输收入影响呈负相关。     

Survey of R&D in PRT systems

A survey of research and development in advanced transit has been made by Chalmers University of Technology in Gothenburg in cooperation with Trans21 in Boston. Summary findings are reported for fourteen academic research programs and ten development programs for PRT. An earlier version of this paper was presented at the International Conference of PRT and other Emerging Systems held in Minneapolis in 1996.     

The Impact of Container Type Diversification on Regional British Port Development Strategies

Abstract

Despite a concentration of container traffic in the southeast of the UK over the last few decades, regional ports are attempting new development strategies to capture or retain specific traffic segments. These include intra-European short-sea traffic and a potentially increasing feeder market. These trends are reflected in the movement of different container types, which result in a number of planning challenges related to changing infrastructural and operational requirements. This paper uses highly disaggregated data on container type movements to address three issues that can inform these planning challenges. First, the imbalance of trade resulting in empty container repositioning; second, the requirement for gauge-cleared rail routes to cater for the increasing proportion of high-cube containers; and third, the specialisation of European short-sea traffic at secondary UK ports. The results reveal the disproportionate repositioning of empty containers at Scottish ports and the importance of 45?ft, high-cube and pallet-wide containers at regional ports, highlighting their focus on intra-European short-sea traffic and raising difficulties relating to their lower quality of landside infrastructure (particularly rail) in comparison to the large south-eastern ports. The potential repercussions on hinterland infrastructure development raise questions about both public and private sector responses to regional port development.     

Modular route bus design – A method of meeting transport operation and vehicle manufacturing requirements

This research examines the problem of route bus specification and vehicle manufacturability. In order for bus operators to provide transport services, a range of vehicle configurations must be available from bus manufacturers, generating variety which has a negative impact on the manufacturing process. Larger part inventories, uncontrolled labour tasks and more troublesome maintenance are known impacts of this variety. This research identifies the functional necessities in route bus interior design and reduces the problems in bus manufacture and operation caused by specification diversity by proposing a modularised system of bus design. In particular, it makes recommendations as to how bus configuration should be carried out, ensuring an optimum mix of operational and manufacturing needs:

• 1.Determine user needs before the bus specification process.
• 2.Designs to be developed by the manufacturer in response to user needs.
• 3.This design should be standardised where possible, as suggested by the user needs.
• 4.Where user needs dictate product variations, apply a mass customisation approach to accommodate these needs.

The recommendations are communicated in design proposals for a modular bus interior, demonstrated by four cases designed to meet the present status quo of bus interior design and predictions for the future of the field.     

管道风险分析指数评分法中分值调整初探

管道风险分析指数评分法中重要步骤之一就是确定影响管道事故因素的权重,各个管道风险因素在整个管道事故中所占的权重是不相同的。针对目前管道风险分析指数评分法基本假设之一（各因素的分值范围都是0～100分）,为了更加客观、准确、合理地反映各个风险因素对于管道事故的影响程度,提出并论述了依据层次分析法的数学逻辑性进行综合计算得出管道风险因素的权重,然后对评分法中各个因素的最高分值,根据其权重不同进行相应调整,从而增强评价者对风险因素的认识和评判能力,提高管道风险评价结果的准确性。     

Determinants of modal choice in freight transport

In the next few years, exciting developments in the field of freight transport are likely to occur. The Channel Tunnel will be perceived as giving railways much greater distance of operation, compared to the current train ferry to/from Great Britain. The further development of swap-body technology will allow easier modal transfer and the creation, in 1992, of a single market in Europe will transform the pattern of trade. All of these are likely to have significant impacts on modal choice, and hence modal split, in freight transport. Reappraisal by many firms of the modes of transport used is likely but will it result in a net transfer of freight from road to rail and, if so, to what extent? To answer such questions, an accurate and reliable method of predicting modal split is required. Research in the past has concentrated on the development of modal split models based on generalised costs. These fail to explain adequately the prevalence of road freight in the UK. From surveys of freight managers within industry, it is clear that models to date rely too heavily on the economic cost factor and too little on behavioural factors (Jeffs 1985). This paper derives from a recent study of freight transport modal choice from the standpoint of the transport decision-maker within the firm. It attempts to shed light on the actual parameters which should be incorporated into a modal split model. Many variables appear to exert an influence on modal choice decision-making process. However, it is possible to categorise them into six main groups, namely: customer-requirements; product-characteristics; company structure/organisation; government interventions; available transport facilities; and perceptions of the decision-maker him/herself. It is the interactions and inter-relationships between these which ultimately determine freight modal split. This study has shown that the relationship between the outcome of the transport decision process and the values of particular determinants of modal split is not straight-forward, due to the complexity and variety of interactions involved. Perhaps one of the main reasons for researchers' failure hitherto to develop a successful modal-split model has been the preoccupation with techniques that rely on the development of common metric (e.g. generalised cost), which has led to the exclusion of some important explanatory variables along quite different dimensions. Another important issue concerns the appropriate level of aggregation. In order not to reduce the explanatory power of the key variables, it is important to work at a disaggregate level, although this does make substantial demands on data. The use of factor analysis enables both the aggregation of information without loss of behavioural reality and the specification of variables in terms of a common metric. In conclusion, freight transport has usually been examined within too narrow a framework. It must be placed firmly within the context of the total industrial process. The demand for freight transport is directly influenced by the level, composition and geographical distribution of production and consumption activities. Freight flows are complex and so it is highly unlikely that a universal mode-choice model can ever be developed. Future research should, therefore, be directed towards developing partial models in response to specific needs of those involved in decision-taking in the freight sector.     

A century of evolution of the accessibility concept

The concept of accessibility has acquired numerous meanings along multiple dimensions during the century of its evolution. This essay argues for the salience of two dimensions: application-based and definition-based. In its application, accessibility has incorporated positive and normative dimensions which have varied in prominence over time. In its definition, accessibility has varied between a mode of evaluation incorporating measured mobility and proximity, on the one hand, and a predefined market basket of urbanist improvements to transportation and land use systems, on the other. Advocates of the accessibility shift should emphasize both the measured approach to accessibility and accessibility’s normative side.     

Optimization of bus stop locations for improving transit accessibility

A mathematical model is developed in this paper to improve the accessibility of a bus service. To formulate the optimization model, a segment of a bus route is given, on which a number of demand entry points are distributed realistically. The objective total cost function (i.e. the sum of supplier and user costs) is minimized by optimizing the number and locations of stops, subject to non‐additive users' value of time. A numerical example is designed to demonstrate the effectiveness of the method thus developed to optimize the bus stop location problem. The sensitivity of the total cost to various parameters (e.g. value of users' time, access speed, and demand density) and the effect of the parameters on the optimal stop locations are analyzed and discussed.     

Productive efficiency and ownership of urban bus services

The established ownership mix of urban bus operations in Australia provides a unique opportunity to investigate the productivity differences between public and private bus service supply. Using duality theory in economics which links economic indices of factor productivity to the cost structure of a firm, we develop empirical measures of total and partial productivity of inputs, and adjust the differences for the effects of ownership status and operating environment. The evidence supports the notion that private supply of public passenger transport in general has performed more efficiently in the past than public supply, although the differences in productivity need not continue in the future.