国际海上救援效率比较研究 ——以东海特定水域为例

为研究东海海域海上救援效率和国际协作的协调性,以国际救援为视角,基于ArcGIS构建了海事救援效率评价模型。根据巡逻船舶密度数据确定了救援船舶的概率分布,得出了救援船舶与遇险船舶的可能距离,同时考虑了风浪影响下遇险船舶的漂移以及巡逻船舶失速的情况,分别计算了常风向和次常风向下中国、日本和韩国在东海特定水域的海上救援效率。结果表明:以各国现有的巡逻船舶配备对研究区内漂移的遇险船舶展开救援时,常风向下先后抵达的顺序为韩国、日本和中国,驰援时间分别为5.14、8.18和9.67 h;次常风向下抵达的顺序为韩国、日本和中国,驰援时间分别为5.45、8.25和10.08 h;为提高我国的救援效率,需要在东海海域部署9～10艘巡逻船舶开展常态化巡逻。本文研究可为我国有关部门科学制定和完善海上救援方案,调整海上救援力量配备,进一步加强国际间的协调与合作提供参考。     

ScotMap: Participatory mapping of inshore fishing activity to inform marine spatial planning in Scotland

A detailed understanding of fishing activity in Scottish waters is required to inform marine spatial planning. Larger fishing vessels are fitted with Vessel Monitoring Systems (VMS) offering spatial information on fishing activity. VMS does not cover smaller vessels (under 15 m), which fish predominantly in inshore waters where the competition for space is often greatest. To improve knowledge of the distribution of fishing activity and value of fisheries in Scotland's inshore waters, Marine Scotland conducted a participatory fisheries mapping project, known as ScotMap. The data were collected during face-to-face interviews with 1090 fishermen of Scottish registered commercial fishing vessels under 15 m in overall length and relate to fishing activity for the period 2007–2011. Interviewees were asked to identify the areas in which they fish, estimate the contribution these areas make to vessel earnings, and to provide associated information. The majority of interviews relate to creel fishing. The data collected were aggregated to provide mapped outputs of the monetary value, relative importance to fishermen and the usage of the seas around Scotland (number of fishing vessels and number of crew). ScotMap outputs provide information on the locations of inshore fishing activities and the economic importance of different sea areas at a much higher spatial resolution than was previously possible. Outputs have informed marine policy development, provide a valuable resource for marine spatial planning in Scotland and illustrate how participatory mapping can generate useful resources on the location and importance of inshore fishing areas.     

Propulsive performance of a tanker hull form in damaged conditions

Many disastrous oil spill accidents from damaged vessels become worse especially when the early treatment is not prompt enough. To properly handle this type of accidents and prevent further disasters, International Maritime Organization establishes and imposes various rules and regulations. Better understanding of the propulsive performance of damaged vessels is important for containing the oil spill while the vessels are being towed or self-propelled. In the present study, both experimental and computational methods were used to investigate the flow phenomena around the hull and the hydrodynamic performances of a VLCC in various damaged conditions. From the resistance and self-propulsion test results, it is found that higher power is required to propel the ship especially with the bow trim. Wake measurement data provide physical insight into the factors to be considered for the propeller operation in damaged conditions.     

基于BiLSTM模型的远洋渔船类型识别研究

船舶自动识别系统(Automatic identification system,AIS)为渔业资源和渔船捕捞活动管理和研究提供了可能.明确船舶作业类型是开展AIS信息渔业研究应用前提,为渔业研究和管理提供渔船捕捞类型基础数据支撑,保障渔船作业安全和监督非法捕捞渔业活动,作者通过搜集整理3000多艘已知类型船舶信息,从...     

Instability Assessment of Deep-Sea Risers Under Parametric Excitation

This study deals with the nonlinear dynamic response of deep-sea risers subjected to parametric excitation at the top of a platform.As offshore oil and gas exploration is pushed into deep waters,difficulties encountered in deep-sea riser design may be attributed to the existence of parametric instability regarding platform heave motions.Parametric resonance in risers can cause serious damage which might bring disastrous accidents such as environment pollution,property losses and even fatalities.Therefore,th...     

Laboratory investigation of single floating booms a and series of booms in the prevention of oil slick and jellyfish movement

Laboratory experiments were carried out to test the effectiveness of single floating booms, and series of barriers in preventing oil slick and jellyfish movement under various current, wind, and wave conditions. Samples of Kuwait light crude, Kuwait heavy crude, and emulsified Kuwait heavy crude oil were selected for the test program. It was found that the single floating booms were only effective in preventing the oil slick movement at current speeds less than 0.15 m/s for emulsified oil and 0.25 nits for non-emulsified oil. Double floating booms (with a distance of 16 times the boom's draught between them) prevented both non-emulsified and emulsified oil movement when current speed was less than 0.25 nits. The double floating boom system had the best performance in containing oil slick movement.In the combined air-bubble barrier and floating boom system, the air-bubble plume lifted the jellyfish to the water's surface, and thus most jellyfish accumulated in front of the floating boom. With the help of a proper collection device (such as a suction pump), the accumulated jellyfish could be removed to a desired location. Therefore, the quantity of jellyfish moving into the intake channel was reduced.Based on the test results, three different arrangements were recommended for the protection Kuwait's water intakes and harbors from oil slick and jellyfish movement.     

Behavioral response of Indo-Pacific humpback dolphin (Sousa chinensis) to vessel traffic

A series of land-based surveys were conducted at two vantage points of known dolphin abundance in Hong Kong. The purpose of this study was to determine the behavioral response of Indo-Pacific humpback dolphin (Sousa chinensis) to vessel traffic. Results indicated that dolphins dove for a longer duration in areas of heavy vessel traffic or when there was the presence of an oncoming vessel. Dependent upon the type of vessel and the relative distance, dolphins might flee, continue their ongoing activity, perform a new activity, or approach the vessel. Whilst slow-moving vessels appeared not to cause immediate stress on the dolphin community, fast-moving vessels often cause disruption of behavior and social life. In order to ensure a better environment for the animals, we suggest that proactive conservation measures such as the creation of a marine park, rules and regulations for dolphin watching activities, and regional control of vessel speed should be implemented.     

Distributional effects of property rights: Transitions in the Atlantic Herring fishery

A principal challenge in developing any fishery management plan is the allocation of benefits and costs among participants in the fishery. This process is further complicated by imperfect information about future market demand and limited ability to predict the consequences of regulatory change. This paper offers a new approach to policymakers, using econometric analysis to simulate the potential impact of individual tradable quotas (ITQs) in a fishery. We compare the distribution of harvest across participants in the Atlantic Herring fishery under the current open access regime and under a potential ITQ regime, assuming two different levels of future demand. Our results show that production efficiency varies by vessel gear, home-port and relationship with buyers. Some of the predicted consequences of ITQs are: vessels from Massachusetts will gain share relative to those from Maine; trawlers will gain share relative to purse seine vessels; and independent vessels will lose share relative to vessels that are primarily contracted to specific processors or bait companies. These results will help policymakers in developing future management plans for the herring fishery. More generally, this analytical approach can help regulators in any fishery assess the potential impact of alternative policy changes under alternative future demand scenarios.     

Experimental study of wave loads on a small vehicle in close proximity to a large vessel

Operations involving the launch or recovery of a smaller vessel from a larger one are extremely dangerous in high sea states and, therefore, they are normally carried out in low to moderate sea states. However, this can be severely restrictive and in some situations, carrying out such operations in high sea states is unavoidable. Here we report on a detailed investigation of the interaction between two vessels of different size in order to characterise their hydrodynamic interaction under different conditions and to provide insight for operational purposes. Model experiments were conducted to investigate the hydrodynamic interaction between two vessels in close proximity in waves. Previous studies into this interaction have focused on two vessels with comparable size/displacement. This study focused on the interaction between vessels of very different sizes, a platform supply vessel and a lifeboat, at various separation distances between the two models and wave headings. It is found that the effect of the hydrodynamic interaction on the wave loads on the lifeboat model is substantial. The load responses show a strong non-linearity (high order harmonic components). In head waves, the effect of the hydrodynamic interaction on the wave loads is greater in the transverse modes (sway, roll and yaw) than in the longitudinal modes (surge, heave and pitch). The sheltering effects of the larger model on the lifeboat model were also evident from the experiments. The results of this investigation may be used to inform the planning of marine operations, such as the launch and recovery of a lifeboat or an Autonomous Underwater Vehicle (AUV) from a mothership and the transfer of equipment or personnel between vessels. The data will also provide a useful resource for validation of Computational Fluid Dynamics (CFD) codes and other numerical simulations, and can be used to better understand the limitations and potential widening of the operational weather windows and to ensure that operations are carried out safely.     

Marine radar interrogator-transponder

The use of ship's radar for collision avoidance presents a fundamental problem in threat detection and identification since all vessel radar returns ("paints") look alike. As a result, when a ship master caught in a fog is trying to use his radio-telephone to work out a maneuvering plan with another vessel, it is difficult for him to identify which blip on the planar position indicator PPI is the source of the voice on the radio. One solution now receiving worldwide attention is to fit all vessels with active transponders. The marine radar interrogator-transponder (MRIT) is an advanced form of transponder which includes an integral interrogator and works in coordination with the ship radar to provide not only target identity and "clutter-free" target paints, but also maneuvering information and such data as target's course, speed, draft, safe or dangerous cargo, etc. Mounted on a fixed navigation aid, the transponder portion alone can also function as a racon (radar beacon). This paper describes the operational parameter and reviews the system bench tests and sea trials.     

A new methodology developed by cetena to assess the seakeeping behaviour of marine vessels

The paper describes an analytical method to determine an operability index for a marine vehicle when its geometric characteristics, the geographical area in which the vessel is supposed to operate, and the limiting criteria for operations are known. The computer program based on strip theory provides reliable results not only for conventional hullforms, but also for catamarans, offshore vehicles, etc. The results are presented in the form of figures for different vessels, namely, crane barge, naval vessels and SWATH type catamarans. The authors are of the opinion that the proposed method would provide the designer with a valid tool to improve the seakeeping qualities of a vessel, while taking into account the limiting conditions imposed due to seaway operations.     

基于深度学习和时空特征融合的海洋渔船密度预测方法

为了从海量渔船轨迹数据中挖掘隐含的信息和知识,进而为渔业行政主管部门的决策提供科学依据,本研究以AIS渔船轨迹数据为研究对象,提出了一种基于深度学习和面向时空特征融合的海洋渔船密度预测方法：首先,利用渔船轨迹数据集对渔船行驶区域进行网格划分;其次,筛选出渔船高密度区域进行研究,避免数据稀疏性问题;再次,根据渔船轨迹数据的时空分析,构建三维时空融合矩阵;最后,通过卷积循环神经网络模型捕获渔船分布的时间和空间特征,并利用卷积神经网络的堆叠加强对空间特征的学习。实验通过东海海域渔船真实轨迹数据进行具体测试,结果表明渔船密度预测值与真实值非常接近,平均绝对误差为4×10-4,模型较好地拟合了渔船密度分布特征,有效地提高了渔船捕捞热点预测的准确性和鲁棒性。     

Estimating spatial and temporal variability of juvenile North Sea plaice from opportunistic data

Surveys are often insufficient to accurately capture the distribution of a species in both space and time. Complementary to the use of research vessel data, platforms of opportunity can be a powerful strategy to monitor species distributions at high temporal and spatial resolution.In this study we use data from commercial fishing vessels, collecting – under the European Union data collection framework – biological data on all species that are caught and subsequently discarded. Using such discard data in combination with a systematic trawl survey, we model the spatial and temporal distribution of juvenile plaice (Pleuronectes platessa) in the central North Sea. There is a clear age-dependent difference between the commercial fishing vessel data and the research vessel data, with age 1 being the dominating age in the survey catches, while age 2 is the dominating age in the discards. The results show how immature plaice, slowly migrate from the nursery areas, westwards into the deeper regions of the North Sea. Also, the results show that during the study period, juvenile plaice gradually moved to deeper waters at an earlier age. Finally we discuss how the framework can be applied to similar opportunistic data to monitor seasonal and inter-annual migration of marine organisms, and to quantify how they may be influenced by biotic and abiotic gradients, such as temperature.     

Fatalities among the world’s merchant seafarers (1990–1994)

This paper presents the findings of a study into fatalities among seafarers serving on board merchant vessels worldwide. Statistics obtained from official maritime authorities are used to provide a comparison of mortality rates among seafarers in 19 different national fleets, and to estimate the number of seafaring lives lost at sea worldwide. This study has the advantage of distinguishing between five different causes of death at sea: deaths through maritime disasters, occupational accidents, illnesses, crewing personnel missing at sea and suicides, homicides and unexplained causes. The findings are compared with those of previous studies and with published statistical information on casualties worldwide. It is evident that statistics released by respected maritime sources grossly under-report casualties arising from disasters involving merchant vessels, and fail to address mortality through all other causes of death at sea.     

Measuring capital value in a commercial fishery: A distance function approach

The term “overcapitalized” is frequently used to describe the condition of various fisheries, and to explain why a fishery is in poor condition from a stock status perspective. Often, the concept of overcapitalization is associated with the number of active vessels in a fishery. Although vessel counts are important, they do not fully capture investment or disinvestment in a fishery, and only serve as a crude proxy for a richer concept of fishing capital. A better measure to judge whether overcapitalization is occurring would be the change in capital value for vessels operating, or permitted in a fishery, relative to a benchmark value. Unfortunately, data do not always exist to measure vessel value and associated changes through time. This study presents a method for calculating vessel capital value using a distance function, publicly available vessel sale price data, and non-parametric programming methods. Estimates of value for vessel attributes returned by the distance function are then used to estimate a total value for currently permitted vessels in the northeast region of the United States, and to construct a capital value index for vessels active in the squid, mackerel and butterfish (SMB) fishery between 1996 and 2016. Findings show that the total value of commercially permitted vessels in the northeast region is estimated to be between $606.6 and $769.7 million ($2016). Based on the constructed capital value index, the SMB fishery has undergone a period of disinvestment marked by both declining vessel numbers and capital value.     

Unravelling the dynamics of a multi-gear fleet – Inputs for fisheries assessment and management under the Common Fisheries Policy

Effective species management requires good knowledge on vessel dynamics, either at a stock basis or through the establishment of multiannual management plans as advisable under the new European Common Fisheries Policy (CFP). Achieving such knowledge on Portuguese multi-gear fisheries is challenging given the large number of species caught and the different management measures applied to potential target species. The latter ranges from no input or output controls to output controls based on individual vessel quotas (IVQ). To provide accurate regional knowledge to the CFP, the dynamics of vessels involved in the trammel net fishery targeting anglerfish (Lophius spp.) was characterised based on onboard sampling data and logbook reports. The selected vessels were very dynamic, and were found to target other species such as hake (Merluccius merluccius), John Dory (Zeus faber) and octopus (Octopus vulgaris). Anglerfish landing trends can be explained by changes in abundance, quota availability and shifts/changes in fishing effort. Overall, the dynamics of these vessels varied with area of exploitation, IVQ value and anglerfish total allowable catch (TAC). These results show the influence of different management systems in the dynamics of vessels and the advantage of an IVQ management system, where fishers can spatially and temporally allocate effort. Results also highlight a fishing effort shift towards unregulated species in face of IVQ or TAC restrictions.     

基于AIS信息校准的双频地波雷达的船只融合跟踪

高频地波雷达（HFSWR）和自动船只确认系统（AIS）是船只跟踪的重要传感器。高频地波雷达可以用来跟踪探测区域的所有船只,而AIS只能用来确认合作船只的信息。由于海杂波的干扰,使用单频率地波雷达的船只跟踪会淹没在布拉格峰值的盲区里,改变探测频率是克服这一缺点的有效手段。在这种背景下,我们提出一种基于AIS校准的双频雷达融合探测算法。因为不同频率的地波雷达测量与AIS的测量值存在系统误差,所以AIS信息可以用来估计和校准地波雷达的每个频率的系统误差。首先,将合作目标的点迹测量与地波雷达的点迹测量通过JVC分配算法进行点迹关联。从合作船只的点迹关联结果中,双频雷达的系统误差可以估计和校准。其次,基于校准的双频雷达数据,使用融合JPDA-UKF算法进行船只跟踪。通过真实探测的数据的实验结果显示所提算法可以实时跟踪船只,相比单频率跟踪可以进一步提高跟踪能力和跟踪精度。     

Mapping human dimensions in marine spatial planning and management: An example from Narragansett Bay, Rhode Island

The Narragansett Bay in Rhode Island is a complex mosaic of human activities and environmental features and while spatial distributions of physical, chemical, and biological elements are well documented in the Bay, there are limited data on spatial distributions of human activities. In this study, human uses of coastal waters in the upper Narragansett Bay are examined using an approach for characterizing and analyzing fine scale spatial and temporal data on human activities. Shipboard transect surveys of active water activities were conducted in the upper Bay on 50 days during the summer months of 2006–2007. The composition and configuration of different vessel types (recreational motor, recreational sail, row boat, commercial fishing, industrial, service, and official) were analyzed, and the impacts of proposed changes in land use policies and wastewater treatment technologies were investigated. Results indicated that recreational boaters comprised almost two-thirds of the upper Bay's users and used over one-half of the study area. Industrial activity was concentrated near Providence where RI's main port is located, and there was an active commercial fishery in the southern portion of the study area. Conditions like increasing cloud cover, weekend days, and the July 4th holiday were related to increased recreational use, while the closure of an upper Bay beach to swimming was associated with fewer commercial fishing vessels and more official boats, recreational motor boats, and service vessels. Findings indicated that upper Bay waters near land converted from industrial zones to zones where residential housing or marinas are encouraged are likely to see a change in composition of vessels, with fewer industrial and official boats and more recreational motor boats, row boats, and service vessels. Enhanced wastewater treatment technologies and the resulting improvements in water quality are likely to make more waters in the upper Bay available to shellfish harvesting, spreading out existing fishing grounds and potential pressures on the ecosystem and on other users. By characterizing the spatial and temporal heterogeneity of human uses in the marine environment and analyzing how these uses relate to the complex human and natural systems in which they are embedded, this study and others like it can positively contribute to marine spatial planning and management efforts designed to achieve ecological, economic, and social objectives.     

Precision in systematic trawl surveys as assessed from replicate sampling by parallel trawling off Namibia

Following independence of Namibia in 1990, abundance of that country's hake stocks was monitored by trawl surveys conducted by the Norwegian F.R.V. Dr Fridtjof Nansen using a systematic survey design. Precision from such designs is considered to be better than with a random design, but it cannot be quantified through standard analysis of variance. In 1998 and 1999, the trawl surveys were duplicated in full using a commercial trawler that operated in parallel with the Dr Fridtjof Nansen. Both vessels had the same fishing gear and rigging. In both years, biomass and distribution patterns estimated by the vessels were similar. The paired datasets collected from the surveys were used to analyse variability in the point samples. Absolute differences between pairs of catches were, in general, proportional to the catch, but they varied randomly following a normal distribution around the catch level. Local variability was analysed as random noise, modelled and later reapplied on single vessel data series to evaluate the effect of sample size and replicates on the survey mean. In a survey with 200 stations, local sample noise accounted for about 4% of the variability in the survey mean. Alternatively, running series of simulated surveys by bootstrapping on pairs of catch data gave similar results, when a small systematic vessel effect was adjusted for. The main statistical techniques applied were less susceptible to outlier catches than straightforward correlations or regressions and could therefore, perhaps with some advantage, also be used to estimate the vessel factor when intercalibrating trawl survey vessels.