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1.
针对海上矿石运输,介绍了一种完成定量任务并能使投资费用最少为目标的最优船队组建方法,同时对易变参数进行了灵敏度分析,使决策更加科学化  相似文献   
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A large artisanal fleet made up of small-sized vessels fishes along the Galician coastline using passive gear and traps. The aim of this study is to analyse the economic profitability of this fleet in the last 5 years by looking at the average rate of return on the vessel and the investment payback period. The results show a slight drop in the return per vessel half-way through the period studied caused by the effects of the Prestige oil spill, to quickly recover over the following 2 years. Considerably high profitability rates from fishing activity were observed, especially in the second half of the period, and slightly lower payback periods, in general, than the average life of a standard fleet vessel.  相似文献   
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The European Union has established a framework to achieve or maintain good environmental status in the marine environment by 2020. The Marine Strategy Framework Directive requires the application of the ecosystem approach to the management of human activities, covering all sectors having an impact on the marine environment. However, fisheries in the Mediterranean are far from a systematic implementation of an ecosystem-based fisheries management (EBFM). Aiming to address this issue, this study explores the potential of the relationship between daily yield by vessel (landings and income by species) and vessel position (known via vessel monitoring system) as a tool for fleet management. This approach is possible due to the current dynamics of Mediterranean fleets, with vessels returning daily to the harbour where landings are registered as weight and income by vessel. Moreover, vessels of >15 m total length have been compulsory monitored by VMS since 2005. A bottom trawl fleet that operates in the northwestern Mediterranean was chosen to develop this approach. Different groups of trawlers were identified, which could be linked to the strategies displayed by the fishermen that were mainly driven by the target species dynamics. Accurate knowledge of the fishing targets driving the fleet dynamics and of the fishing strategies at the vessel level (i.e. fishing ground habitat where the fishing pressure is exerted and corresponding landings) are shown to be a feasible tool for fleet management.  相似文献   
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寿建敏 《极地研究》2018,30(4):419-428
我国在南极和北极的活动日益增多,参与南北极事务和争取极地资源的利用已经成为国家未来向外扩展的重要举措之一。随着气候变暖,极地冰融速度加快,尤其是北极航运窗口期越来越长,两极资源利用和科考活动的需求量越来越大。而目前我国用于航行两极,尤其是北极的高冰级商业化船队十分缺乏,航运的陆基支持保障能力缺少,这将严重影响我国极地事业和商业航运运营的发展。本文通过对不同冰级船舶的保有量、建造技术能力、船舶运营和极地港口设施等各环节的分析,得出我国缺乏带较高等级冰级符号且可抗浮冰厚度1m及以上的极地航行船舶、相应极地航运能力不足的结论,并提出了我国建设极地航运能力的对策建议,为我国建设一支能在极地航行且带较高等级冰级符号船舶的船队、破冰船队以及建设极地陆基航运支持保障能力等提供决策参考。  相似文献   
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Peruvian anchovy (Engraulis ringens) stock abundance is tightly driven by the high and unpredictable variability of the Humboldt Current Ecosystem. Management of the fishery therefore cannot rely on mid- or long-term management policy alone but needs to be adaptive at relatively short time scales. Regular acoustic surveys are performed on the stock at intervals of 2 to 4 times a year, but there is a need for more time continuous monitoring indicators to ensure that management can respond at suitable time scales. Existing literature suggests that spatially explicit data on the location of fishing activities could be used as a proxy for target stock distribution. Spatially explicit commercial fishing data could therefore guide adaptive management decisions at shorter time scales than is possible through scientific stock surveys. In this study we therefore aim to (1) estimate the position of fishing operations for the entire fleet of Peruvian anchovy purse–seiners using the Peruvian satellite vessel monitoring system (VMS), and (2) quantify the extent to which the distribution of purse–seine sets describes anchovy distribution. To estimate fishing set positions from vessel tracks derived from VMS data we developed a methodology based on artificial neural networks (ANN) trained on a sample of fishing trips with known fishing set positions (exact fishing positions are known for approximately 1.5% of the fleet from an at-sea observer program). The ANN correctly identified 83% of the real fishing sets and largely outperformed comparative linear models. This network is then used to forecast fishing operations for those trips where no observers were onboard. To quantify the extent to which fishing set distribution was correlated to stock distribution we compared three metrics describing features of the distributions (the mean distance to the coast, the total area of distribution, and a clustering index) for concomitant acoustic survey observations and fishing set positions identified from VMS. For two of these metrics (mean distance to the coast and clustering index), fishing and survey data were significantly correlated. We conclude that the location of purse–seine fishing sets yields significant and valuable information on the distribution of the Peruvian anchovy stock and ultimately on its vulnerability to the fishery. For example, a high concentration of sets in the near coastal zone could potentially be used as a warning signal of high levels of stock vulnerability and trigger appropriate management measures aimed at reducing fishing effort.  相似文献   
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Kyriaki Mitroussi   《Marine Policy》2008,32(6):1043-1049
The EU is the leading maritime power with approximately 3 million people in total working in its thriving maritime industries. It is the aim of the present paper to examine the status of the EU-registered and -controlled fleet, provide an overview of contemporary forces in the shipping business, which affect employment of EU seafarers, and discuss principal EU initiatives in support of the competitiveness of the EU shipping and employment opportunities for EU nationals in it. Among the issues under consideration will be the role and effect of third party flags, cost considerations, the maritime cluster effect, and regulatory burdens.  相似文献   
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