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1.
In this paper are presented the results of a multinomial logit model used to explain the selection of a port for each shipment exported from the US in December 1999. The model is estimated for combined shipments, and one model is estimated for each of four commodity types (bulk, foods, fabrics, manufactured). Results are compared across commodities to find the significance of the distance in either direction, the frequency of sailings, and the average size of vessels sailing along a route. Results of the estimation do not match those that would be expected. Potential reasons are given for such variations, along with numerous methods by which the modelling could be improved. Methods for improvement suggested include structuring of the model to represent more accurately the competitive scenario of each port, constraining the choice set for each shipments from characteristics of the carrier, and the commodity.  相似文献   

2.
A mathematical spatial programming model developed to analyse changes in international and hinterland commodity flows through a regional port system is applied to wheat shipments through the U.S. Pacific Northwest port system. Two scenarios, one focusing on a Chinese quarantine on wheat shipments from the Pacific Northwest and the other on possible closure of barge transportation on the Columbia-Snake River, illustrate the capacity of the model to evaluate the impacts of international and hinterland shocks on the regional port system.  相似文献   

3.
For the economic and financial evaluation of port investment projects, it is important to know the demand function of a port's services. The objective of this study is to establish such a demand choice function for the Spanish container port services. The function is derived from the coefficients of a port choice model, for which a multinomial logit model is used and of which the coefficients are estimated with regression analysis. The variables tested concern inland transport cost, ocean transport costs and broad proxy variables for quality of service. Information on container import and export flows for 2007 is obtained from the Spanish Treasury Department. The linear regression analysis is based on differences of utilities of alternative routings of containerised cargoes compared to those routed via the port of Valencia. The obtained results are satisfactory in terms of model fit. The estimated coefficients can be used to assess the impact of changes in costs of container flows routed via a port on a port's market share. A demand choice function for the port can be derived by systematically doing so. An example is presented for the port of Valencia.  相似文献   

4.
This paper develops a conceptual framework that integrates various relevant port performance components in a way that can be used for a comprehensive port evaluation and adjustment of existing port governance models. The paper presents a synthesis of the literature on port governance models and port performance, arguing that the process of change is a dynamic one, and that the performance outcome of a reform process influences the next round of reforms. It also explores the potential for decomposing performance into two different, although related, port performances components, namely efficiency and effectiveness. Bringing into the analysis concepts like the need to integrate users’ satisfaction in port performance assessment, the paper explores the content of each of these components and their relationship. This discussion, along with empirical evidence provided by port authorities, leads to the conclusion that governance decisions, both at firm and government levels, are largely based on a very limited assessment of port performance. The effectiveness of port reform is largely neglected, with user perspectives not being an integral part of an effort to improve performance by the port or as feedback to assess the effectiveness of the governance model imposed by the government's port policy.  相似文献   

5.
This paper demonstrates the validity of relative shift technique toward aiding the port geographer/planner in decision-making. The technique can be applied with a minimal of effort and yield diagnostic information concerning port commodity flows. A broad overview of New England's port facilities is presented, and the technique is then applied to an individual port, Boston.  相似文献   

6.
This paper proposes a model system developed in order to support ex-ante assessment of city logistics measures. The model system allows us to simulate the choices of each decision-maker involved in the urban freight transport and logistics and to investigate how the policies and the following measures can influence her/his choices.The model system is an open architecture and consists of two levels: commodity and vehicle. The commodity level allows us to analyse the attraction and acquisition movements taking into account the effects due to city logistics policy implementation affecting the end-consumer and retailer/wholesaler/producer (restocker) choices. The freight sold in each urban shop (or in general urban business) is estimated starting from consumption demand and, then, the restocker’s choices for restocking are analysed in depth. The vehicle level focuses on the restocking process and the links between retailer and wholesaler/producer operating in the study area. This level allows us to investigate the impacts of implementing city logistics measures on journey time, timing and path used for restocking the urban retail businesses.  相似文献   

7.
超大型船舶栈桥码头安全系泊技术试验研究   总被引:1,自引:0,他引:1  
系泊安全问题,随着超大型船舶运输和开敞式深水泊位的出现日益显得重要。这类事故不但造成船舶的重大损失,还直接威胁港口的安全。本文以模型试验为基础,对影响系泊安全的各相关因素进行了定量测试,获得了大量数据,再根据实地潮流资料,对中国远洋运输公司“普安海”轮系泊北仑港和宝钢主原料码头时所受的流压力的数值范围进行了估算。最后本文列出系泊安全的技术措施,为船舶安全生产和码头泊位设计提供了参考依据。  相似文献   

8.
商品车物流是商品车销售的一个重要环节。港口有必要凭借其独特的区位优势和基础设施优势,逐渐向综合汽车物流中心的方向发展。介绍了物流的现状和特点。分析了烟台港商品车物流的现状和发展前景。对烟台港发展商品车滚装运输提出了一些建议。  相似文献   

9.
基于CJK3D-WEM模型,建立长江口横沙港区数学模型,研究横沙港区形成后周边水域的水动力变化。结果表明:横沙港区方案实施后,各汊道断面分流比变化较小;南港河段、北槽中上段涨落急流速均有不同程度增加,北槽下段涨、落急流速略有减小,南港—北槽航道的落潮优势流略有变化,仍表现为明显的落潮优势;北港沿程落急流速变化较小,涨急流速北港口外段增加,其余区段减小。方案的实施对长江口拦门沙地区的总体河势格局不会产生明显影响。  相似文献   

10.
基于供应链思想的第四代港口概念特征及发展策略研究   总被引:1,自引:0,他引:1  
与第一、二、三代港口不同,第四代港口从强调自己是一个“物流中心”,转变为强调是供应链中的一个环节,为此,有必要研究基于供应链管理思想的第四代港口的若干问题。在给出具有供应链管理特征的第四代港口的定义的基础上,提出了港口与供应链关系的演进模型,指出港口与供应链关系发展经历了分离(即相互独立)、整合(即形成港口物流服务链,为制造业供应链提供高效的增值服务)和嵌入(即港口被嵌入到制造业供应链中)三个阶段。应对供应链管理的要求,第四代港口应具有与前三代港口不同的差异化、精益化和敏捷化特征。基于上述分析,第四代港口的发展策略应为,主动整合并构建自身的供应链和与供应链核心企业联合等。  相似文献   

11.
More than a century ago far-sighted railroad builders and steamship operators were seeking the shortest intermodal itineraries between the eastern United States and the Orient. A combination of locational fact and the factual outcomes of 19th century railroad building left Chicago roughly equidistant in railway mileage from what became the four great US West-Coast port complexes in the Los Angeles, San Francisco, Portland and Seattle regions. Their nearly equivalent rail access to Chicago and points east has renewed significance in the container era.

This paper concerns the efforts of US Pacific seaboard ports to stay 'on the beaten track' with respect to container shipments between Asia and the eastern United States. The West-Coast ports are transit points dividing the transcontinental and transoceanic segments of long intercontinental journeys. From origins to destinations there are, in fact, many possibly feasible itineraries, including all-water routes.

The West-Coast ports have considerable control over their own site improvements. On the other hand, with respect to transiting container traffic, the ports may influence, but are unlikely to control, their own situations. Since the major container port facilities are very often on long-term lease to large intermodal carriers, the latter are making the important shipping and routeing decisions. The carriers tend in fact to set the tone and level of port competition.

What is the nature of the competition between container ports? Is it a figment of the publicist's imagination and perpetuated by irrelevant statistical boasting? Is it perhaps something forced on the ports by carriers eager to play one port off against another in a 'lowest bid' game? At what geographical scale might port competition be most useful or, maybe, least wasteful?  相似文献   

12.
以以色列南部新建Ashdod码头为工程背景,在分析港区自然条件的基础上,利用二维河口与海岸模拟软件MIKE21,建立了基础方案各个施工阶段港内泊稳模型。通过对不同施工阶段下半掩护港区波浪场进行数值模拟分析,掌握了港内波浪场的分布情况,确定港内正常施工时防波堤口门处的容许波浪要素。根据防波堤口门处的波浪统计资料,得到港区不同区域的最大作业波高标准以及港区不同区域不同施工阶段下全年不可作业的天数。研究结果为工期的合理安排和作业窗口的确定提供依据,并提出了科学合理的施工工序建议。  相似文献   

13.
基于港口建设导致近岸沿线海、陆域生态系统环境逐渐退化的现状,以集装箱港区为例,进行港区陆域低影响开发研究。将海绵城市低影响开发概念融入港区建设,通过引入合理水文径流分析模型,对港区各功能区的低影响开发提出径流控制要求;同时,采用创新性的平面及结构设计方案满足低影响开发控制要求,促进集装箱港区雨洪资源的重复利用。结果表明,在各类码头中,较为适合进行低影响开发的主要为件杂货及集装箱堆场;海绵港区须重点针对堆场及道路进行低影响开发。  相似文献   

14.
厦门港刘五店港区岸线规划试验研究   总被引:2,自引:0,他引:2  
厦门港刘五店港区将发展为对台"三通"的重要口岸。文中通过物理模型试验,研究了不同岸线方案条件下港区附近水流条件和泥沙回淤强度。试验结果表明,刘五店港区建设对同安湾影响较小,其规划方案是可行的。可为刘五店港区岸线规划布置提供科学依据。  相似文献   

15.
A mathematical model for optimizing the location of dry ports is developed. The objective is to minimize the sum of the transportation costs and the fixed facility opening/closing costs. Unlike previous research on this subject, the possibility of closing existing dry ports is investigated. The dry port location problem is formulated as an integer programming and it is shown that the CFLP is a special case of our problem. The proposed model is then applied to the port of Tianjin in China and the sensitivity analysis is performed to demonstrate the robustness of the model. Our model suggests that while Tianjin Port should open some new dry ports, it might be better off closing those existing dry ports without enough throughputs. Although all parameters estimated should be uncertain in reality, sensitivity analysis shows that the results returned by the model are quite stable.  相似文献   

16.
基于条件期望的港口货物吞吐量预测模型的建立与分析   总被引:1,自引:0,他引:1  
为了有效预测港口货物总吞吐量的大小,利用条件数学期望提出了港口货物总吞吐量的预测模型.由于货物总吞吐量的变化与到达港口的货运船数目以及装卸设备的工作效率有密切关系,构造一个关于到达港口的货运船数目以及装卸设备的工作能力组合而成的复合变量,货物总吞吐量是这些复合变量所表示的货物装卸量的和.应用全概理论,得到货物总吞吐量的概率分布.在此基础上,将未来货物总吞吐量看作已完成吞吐量的条件期望.利用增长函数得出港口货物吞吐量的预测模型.以山东地区某港口的货物吞吐量变化规律进行了案例分析.理论分析和案例分析均表明该模型是预测港口货物总吞吐量的有效方法.  相似文献   

17.
The objective of this article is to analyse the factors that affect port competitiveness from the perspective of the agents and companies that operate in one of the Mediterranean ports most active in container traffic: the Port of Algeciras Bay (PAB). It is essential to understand the perspective of the suppliers of port services, in order to apply the necessary judgment when formulating policies to strengthen the competitive position of a port. The model selected to meet the objective outlined is based on the ‘extended diamond’ of Porter. The universe for the study comprises all the institutions and companies involved in the containerization process in the Port of Algeciras Bay. Within this methodology, two procedures are utilised. First, from the quantitative perspective, a survey has been conducted to obtain responses to two groups of questions, one dealing with situation and the other with perceptions. Second, and from a qualitative perspective, several open interviews have been conducted to corroborate the responses obtained to the questionnaire. From the data obtained in the survey, a model has been estimated that minimises the sum of the residuals in absolute value, utilizing the L1 regression; this model enables the competitive advantages and disadvantages of the PAB, from the point of view of the port operators, to be determined by an analysis of residuals. This analysis demonstrates that the variables representing greater competitive advantages are associated with trans-shipment, and with the maritime accessibility of the Port to vessels, whereas those generating greater disadvantages are associated with rail transport (which, according to those surveyed, has resulted in the diversion of significant volumes of traffic to other Spanish or European ports with better communications, particularly Valencia, Barcelona and Gioia-Tauro, and with the state of competition in container trans-shipment activities.  相似文献   

18.
The objective of this article is to analyse the factors that affect port competitiveness from the perspective of the agents and companies that operate in one of the Mediterranean ports most active in container traffic: the Port of Algeciras Bay (PAB). It is essential to understand the perspective of the suppliers of port services, in order to apply the necessary judgment when formulating policies to strengthen the competitive position of a port. The model selected to meet the objective outlined is based on the 'extended diamond' of Porter. The universe for the study comprises all the institutions and companies involved in the containerization process in the Port of Algeciras Bay. Within this methodology, two procedures are utilised. First, from the quantitative perspective, a survey has been conducted to obtain responses to two groups of questions, one dealing with situation and the other with perceptions. Second, and from a qualitative perspective, several open interviews have been conducted to corroborate the responses obtained to the questionnaire. From the data obtained in the survey, a model has been estimated that minimises the sum of the residuals in absolute value, utilizing the L1 regression; this model enables the competitive advantages and disadvantages of the PAB, from the point of view of the port operators, to be determined by an analysis of residuals. This analysis demonstrates that the variables representing greater competitive advantages are associated with trans-shipment, and with the maritime accessibility of the Port to vessels, whereas those generating greater disadvantages are associated with rail transport (which, according to those surveyed, has resulted in the diversion of significant volumes of traffic to other Spanish or European ports with better communications, particularly Valencia, Barcelona and Gioia-Tauro, and with the state of competition in container trans-shipment activities.  相似文献   

19.
As of late, the Korean government needs quantitative information on economic feasibility analysis for marina port development projects. This study applies a choice experiment to measure public preference for the attributes of marina port in Korea. We consider the trade-offs between price and four attributes of marina port (capacity, access, waterfront, and program) for selecting a preferred alternative and elicit the marginal willingness to pay (MWTP) estimates for each attribute. We also test whether irrelevant alternatives property for the estimation model holds and compare the estimation results of the multinomial logit (MNL) and the nested logit (NL) models. The results show that the NL model outperforms the MNL model. In the NL model, MWTPs for increasing the level of a waterfront from promenade to both promenade and rest area and for the provision of marine leisure experience program are KRW13 384 (USD11.8) and KRW17 937 (USD15.8), respectively. This study is expected to provide policymakers with quantitative information for evaluating marina port construction projects in Korea.  相似文献   

20.
带流水孔潜体流场数值模拟   总被引:10,自引:1,他引:9  
本文通过求解RANS方程,结合PISO算法与k-ω湍流模型,数值模拟了带有两种不同形式流水孔(纵缝式与格栅式)潜体的内外流场.数值模拟给出了流水孔流场的精细结构,计算并分析了潜体各个壁面上阻力成分的大小与成因.计算得到的流水孔阻力增量与试验值吻合较好.对计算结果的分析表明:流水孔引起的阻力增量主要集中在导流板与流水孔壁上;内部空腔壁上的阻力值是可以忽略的小量;涡旋流动主要集中在导流板之间;流水孔阻力系数随雷诺数的增加而趋于一稳定值.计算结果表明,本文中使用的方法可用于模拟流水孔内外流场.  相似文献   

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