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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
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In order to understand characteristics of low-frequency motions of ships moored inside ports and harbors, analysis on actual cargo handling logbook of stevedoring services company, including events of interruption of cargo handling, and countermeasure for ship mooring problems are investigated by field observations at two ports and numerical simulation on moored ship motions. First model port concerns with interruption of cargo handling due to the low-frequency motions. Second model port relates to a resonant effect of long-period waves or harbor oscillations, and its countermeasure by mooring system. From the investigation, it is confirmed that the low-frequency motions of ships are induced by a resonance between surge motions and long-period waves or harbor oscillations and an asymmetry in the mooring system, and affect safe ship mooring and operation efficiency of cargo handling in ports and harbors significantly. 相似文献
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采用工程仿真软件SIMIO分别对秦皇岛港10万吨级航道及规划的20万吨级航道的通过能力进行模拟。首先用2014年秦皇岛港泊位和航道设施及到港船舶数据对模型进行验证,得到的年到港船舶数及航道货运量与实际统计结果基本相符;结合仿真结果,对两航道的货运量、船舶平均待泊时间AWT以及港口服务水平随船舶平均到港时间间隔的变化趋势进行分析;讨论了航道及泊位利用率随港口服务水平的变化;针对10万吨级航道,对比了仿真与航道利用率法的年通过能力结果,并指出确定航道通过能力时考虑港口服务水平及港内作业各环节相互关联性的必要性。 相似文献
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天津港复式航道的探讨 总被引:1,自引:1,他引:0
天津港主航道可双向航行25万t级船舶,目前大小船混行,船流密度太大。根据预测2020年吞吐量将达到7亿t,到港船舶将进一步增加,届时主航道将难以适应。通过分析多年实际到港船舶资料和预测,70%以上为万t级以下船舶,据此提出在现主航道南北2侧各挖1条万t级单向航道,专供万t级以下船舶使用,万t级以上船舶仍航行主航道。大小船舶分道航行形成的复式航道,可以适应今后吞吐量发展的需要。同时调整进港锚地,避免进出港航行交叉。 相似文献
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Jose Tongzon 《Maritime Policy and Management》1991,18(1):55-68
This paper aims to develop an integrated model for forecasting both the number of ship visits and their characteristics in the medium and long term. Knowledge of future shipping trends for any port is no doubt important, as the future number of ship visits and their characteristics may have implications for the physical facilities of a port. In addition, more reliance on tonnages as a revenue source has made this knowledge more valuable. The proposed model identifies such major economic determinants as the expected trade throughput, world shipping trends, standards of facilities and future plans of shipping companies/agents. The model examines three possible scenarios for the Port of Melbourne and produces a range of shipping forecasts based on certain assumptions. From the model the major findings were:
world trends in shipping did not have any immediate impact on the shipping trends at the Port of Melbourne;
Future shipping services at the Port of Melbourne in the next 11 years are most likely to be determined by trade demand rather than by technological developments overseas;
there has been no evidence to indicate that the Port of Melbourne has been excluded from the schedule of general cargo ships due to the Port's physical constraints. 相似文献
world trends in shipping did not have any immediate impact on the shipping trends at the Port of Melbourne;
Future shipping services at the Port of Melbourne in the next 11 years are most likely to be determined by trade demand rather than by technological developments overseas;
there has been no evidence to indicate that the Port of Melbourne has been excluded from the schedule of general cargo ships due to the Port's physical constraints. 相似文献
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位于海南岛西北部的洋浦港既是海南省航运大港,其防台锚地亦是海南岛优质防台锚地,每年防台期间,来港防台船舶远超防台锚地船舶理论保障数,台风期间船舶险情事故频发,造成了船员人身危险及船舶财产巨大损失。文中就洋浦港船舶防台安全形势及影响防台锚地锚泊安全的因素进行分析研究,尝试提出建议,希望能为海事部门及船舶解决防台船舶锚地选择问题提供一些帮助,保障辖区防台船舶安全。 相似文献
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港池口门宽度取决于进出口船舶大小、船舶操纵性能以及风浪流等对船舶航行的影响程度。文中针对罗泾港区港池布置方案、设计代表船型、风浪流条件,运用船舶操纵模拟器进行模拟试验研究。通过大量的模拟试验,分析了风浪流对船舶操纵的影响,确定了港池口门的合理宽度为300 m。经码头建成以来船舶进出和靠泊检验,证明目前港池口门宽度是合适的。 相似文献
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液化天然气(LNG)船舶进出港时通航排他性强,有必要进一步研究LNG码头适宜规模,以科学引导大型LNG接收站建设.基于多智能体信息交互的港口运营系统仿真方法,建立单个LNG港址单向专用航道模型,研究高负荷状态下2~6个LNG泊位时的船舶进出港及接卸作业全过程,评估LNG船舶相互影响状况下的进出港效率.结果表明,基于目前一般通航规则,单个港址LNG泊位数量2个较优,3个相对平衡,不宜超过4个.当达到4个泊位时,船舶进出港效率明显下降,潜在运营风险较高;且随着泊位数量进一步增多,效率会持续下降. 相似文献
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This paper investigates the simulation modelling of cruise ship traffic in the Boka Kotorska Bay (BKB), which has become a very attractive cruise destination due to its geographic location, port features and attractiveness for tourism. The purpose of this paper is to examine the development of new port infrastructure, because of the increased cruise ship arrivals in recent years. The paper describes in detail the layout of the port of Kotor and the possibilities for quay extensions. The solution to minimize the number of ships at anchorage instead of being at berth is given, because the passengers of the latter ships have a more convenient approach towards the port. The simulation model is verified and the simulation results are validated against the real data prior to an investigation of the possible scenario for quay extension. The proposed solution confirms the preliminary survey results that initiated the investigation of possibilities to improve the port infrastructure. Moreover, simulation results point towards a significant improvement of cruise ships throughput in the BKB. The proposed operational policies and statistical analysis, as well as a comprehensive model analysis of the BKB provided here, are a good foundation for future investigations. 相似文献
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Recently, shipping lines have focused on efficient ship operation, which relates to energy efficiency issues in shipping and, particularly, to operational issues such that the minimisation of fuel consumption and resulting greenhouse gas emissions. Efficient ship operation in container lines is closely related to the ship’s time at sea and ship’s time in port. Reduction in port time, thanks to high-quality port operations, allows improvement in the operational efficiency of a liner service by reducing the fuel consumption of a ship at sea and its resulting CO2 emissions. The main goal of this article is to investigate how time in port affects efficient ship operation in terms of operating costs, CO2 emissions and externalities. For this, as a methodology, a simulation based upon system dynamics is introduced. Major finding is that less time in port resulting from the improvement of port operations contributes to efficient ship operation in terms of operating costs, amount of CO2 emissions and external effects in the liner shipping industry. In particular, a sensitivity analysis on efficient ship operation vis-à-vis the quality of port operation shows that bigger ships need to select highly productive calling ports that provide less time in port. 相似文献
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散货船装载的镍矿、铁矿在运输过程中会发生流态化,流态化导致货物流动性增强,从而降低船舶稳性。当船舶在波浪中航行时,货物的移动会产生一个额外的力矩,该力矩有可能导致船舶倾覆。基于离散元方法,对不同含水率的货物进行了静倾斜、休止角的数值模拟,在全尺度计算中给定了颗粒尺寸和时间步长的选取标准,并采用全尺度货舱模型分析了影响货物稳定性的关键参数。该数值分析方法可为固体散货海上运输过程中船舶稳性预测和安全隐患评估提供参考。 相似文献
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Edwin Van Hassel Hilde Meersman Eddy Van de Voorde Thierry Vanelslander 《Maritime Policy and Management》2013,40(2):192-208
In recent years, an increase in the size of the container ships could be observed. The question is how these larger ships will influence the total generalised costs from a port of loading to a destination in the European hinterland. The second question is whether a scale increase of the container ships on other loops, such as a loop from the United States to Europe, has the same impact on the generalised chain costs as on the loop from Asia to Europe. A derived question is which element of the total chain has the highest importance, and whether this balance varies as the ship size changes. In this article, a model is developed that allows answering the above research questions. The model is designed to simulate the cost of a complete loop of a container ship and of a chain that uses that same loop. For the chain cost simulation, the maritime part is determined by the loop. From the ports of loading and unloading, the port container handling and the hinterland transportation costs are also integrated. The model also allows calculating the total chain cost from a point of origin (either a hinterland region or a port) to a destination point (also a port or a hinterland region). An actual container loop of a container shipping company can be introduced in the model. An application is made to two existing container loops, namely from Asia respectively the United States to Europe. It turns out that changing ship does indeed lead to economies of scale, but also that the impact is larger on the Asia–Europe connection than on the US–Europe connection. Furthermore, the maritime component has the biggest share in the total chain cost, but as ship size increases, the shares start getting closer to each other. This research contributes to the existing literature in two ways. First of all, it quantifies the impact of the scale increase of container ships throughout the total chain. Second, this is done from a bottom-up engineering modelling approach. 相似文献
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S. Gilman 《Maritime Policy and Management》2013,40(2):95-102
The introduction of unit load methods, particularly the cellular container system, has been associated with a large increase in ship size on some of the world's major general cargo routes. In this sector, ship size is determined by a set of interactions between handling performance, route length, traffic flow, itinerary, requirements for frequent and regular service, port costs and general system organization. This paper explores these relationships to identify major influences and to consider the prospects for further growth. 相似文献
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S. Gilman 《Maritime Policy and Management》1975,3(2):95-102
The introduction of unit load methods, particularly the cellular container system, has been associated with a large increase in ship size on some of the world's major general cargo routes. In this sector, ship size is determined by a set of interactions between handling performance, route length, traffic flow, itinerary, requirements for frequent and regular service, port costs and general system organization. This paper explores these relationships to identify major influences and to consider the prospects for further growth. 相似文献