内河AIS服务性能指标研究与平台设计

针对当前内河AIS服务性能评价指标单一且实船测试过程复杂等问题,从单船、单个基站和航段区域3个角度,提出内河AIS服务性能评价指标。在此基础上,设计了基于长江电子航道图的AIS服务性能分析平台,通过多条件数据查询、数据处理,实现评价指标的计算以及历史AIS数据的显示。以长江岳阳航段为例,开展AIS服务性能分析平台测试。测试结果显示:单船丢包率差异较大([6. 73%,62. 43%]);基站间存在覆盖区域相互重叠的现象,导致单个基站的丢包率约为45%;航段区域整体丢包率和错误率分别为16. 63%和1. 57%。分析结果表明平台可有效实现AIS服务性能分析与数据可视化,从而保障内河AIS数据的可靠性,提高海事管理和服务的水平。     

跨海通道影响下大连湾水域规划调整方案比选

介绍了受大连湾跨海交通工程影响而开展的大连湾水域规划调整方案比选研究过程。针对大连湾内水域通航环境,分析了港口及相关产业的发展趋势,综合预测了各港区通航代表船型。以大连湾跨海交通工程北桥南隧线位方案为边界条件,根据大连湾水域条件和通航需求,通过引入“具有一定保证率的通航代表船长”的概念,合理确定了跨海通道桥梁与锚地、航道边界的安全距离。给出3种调整方案并进行比选分析,提出了工程后续实施过程中需注意的问题。     

城市轨道交通隧道场景基于射线追踪技术的LTE-M系统性能仿真方法研究

城市轨道交通特殊场景下对LTE-M(城市轨道交通车地综合通信系统)系统性能进行准确评估是一个非常复杂的问题。提出了基于射线追踪技术的LTE-M系统性能仿真方法。该方法无需进行信道测量,通过海量计算即可得到无线信道特性参量,进而进行性能仿真,特别适合城市轨道交通等缺少标准信道模型的场景。     

长江南京以下沿江港口对12.5m深水航道的效益响应

将长江南京以下9个规模以上沿江港口作为12. 5 m深水航道的受益对象,利用2009—2017年港口吞吐量资料分析评价12. 5 m深水航道开通对长江南京以下沿线港口的影响及实际效益。结果表明,12. 5 m深水航道开通以来沿江港口货物总吞吐量整体呈平稳增长态势,2016年初通至南京后,货物总吞吐量年增长率达到8%; 2017年南京以下主要港口完成的货物总吞吐量(24. 25亿t)是2009年深水航道开通前的1. 8倍;深水航道开通后集装箱吞吐量涨幅最明显,散杂货吞吐量占比则较开通前略有下降; 12. 5 m深水航道开通8年来,南京以下沿江港口经济效益整体呈平稳增长态势,2017年产生的港口经济效益(13. 4亿元)比2010年增长近60%。未来随着航道、船舶以及沿江港口码头等条件的持续改善,12. 5 m深水航道的综合效益还将进一步凸显。     

Cash flow sensitivities during normal and crisis times: Evidence from shipping

Using a system of equations model, we analyze how cash flow shocks influence the investment and financing decisions of shipping firms in different economic environments. Even financially healthy shipping firms felt strong negative effects on their financing activities during the recent crisis. These firms were nevertheless able to increase long-term debt. Banks internalized the impact of foreclosure decisions on vessel prices and avoided an industry-wide collateral channel effect. Even during benign economic conditions, financially weak shipping firms underinvest because of their inability to raise sufficient external capital. The substitution between long- and short-term debt during the pre-2008 crisis periods shows that the composition of financing sources is more indicative of whether firms face financial constraints than the pure size of the financing-cash flow sensitivities. An analysis of firms’ excess cash holdings confirms the importance of financial flexibility.     

High speed rail passenger segmentation and ticketing channel preference

A multi-channel strategy for the purposes of marketing and ticketing has been widely employed in various fields, including the transportation industry, yet few transportation studies have investigated ticket channel-related issues. This study thus adopts Taiwan High Speed Rail (THSR) as a case study to identify passengers’ perceptions regarding key factors that affect the channel preference through which they receive their services, particularly across a four-stage ticket purchasing process, including information enquiry, booking, payment, and ticket pick-up. To investigate these key factors, we base the framework of our research model upon customers’ perceived value perspective, adopting a multinomial logit model to examine the influence of channel attributes on HSR passengers’ preferences. The relationship among the decisions made by these passengers at each ticket purchasing stage is also examined. The findings of our study demonstrate that perceived risk, perceived benefit, and perceived ease of use are critical factors influencing passengers’ channel preference throughout the ticket-purchasing process. Perceptual differences are proven to exist due to various demographic factors and trip characteristics. The conclusions of this study have implications for THSR management to design appropriate ticketing channel services for certain types of passengers and can also be generally applied to multiple distribution channels in conventional railway system and intercity bus services.     

区域综合货物运输通道规模研究

在分析已有运输通道研究文献的基础上对货物运输通道的合理规模进行研究,分为通道规模计算,通道中运输方式选择及合理通道规模模型的建立3部分,得出的货物运输通道规模能满足预测规划年的货流需求并留有一定的后备系数,对区域综合运输通道的建设规模研究有一定的价值。     

城市快速路智能交通通信系统

城市快速路智能交通通信系统是城市快速路智能交通系统的基础支撑平台,负责智能交通系统的信息传输和交换,是智能交通系统建设成功与否的关键因素。根据以往的工程经验,从设计及施工角度,介绍我国当前城市快速路智能交通通信系统的通信管道及通信系统,可为城市快速路智能交通通信系统的建设提供技术支持。