Fishers’ knowledge indicates short-term temporal changes in the amount and composition of catches in the southwestern Atlantic

The scarcity of data on fish catches difficult management of small-scale fisheries in developing countries. This study applies fishers’ knowledge to investigate temporal changes in the amount (biomass) and composition (major ecological categories) of fishing resources exploited by small-scale coastal fisheries in the southeastern Brazilian coast. Four hypotheses were investigated: (1) The amount of fish caught reported by fishers would decrease over time. (2) Older fishers would report higher fish catches than younger fishers. (3) Recent interviews would mention large-sized predators less often. (4) Recent interviews would mention less high valued fishing resources. Interviews with 421 fishers in 36 communities in the southeastern Brazilian coast were analyzed, covering a time span of 14 years, from 1995 to 2009. The hypothesis 1 was confirmed, 3 was partially confirmed, while 2 and 4 were not confirmed. Fishers’ age was unrelated to all variables. The results from fishers’ interviews indicated the temporal trends of: (1) a decrease in the biomass of fish caught; (2) an increase in the occurrence of smaller fish and invertebrates in the catch; (3) an increase of high value fishing resources; and (4) maintenance of large predators. The first two indicators suggest excessive fishing, but the later indicators (3 and 4) suggest that the socioecological system of the southeastern Brazilian coast had not yet undergone major ecological shifts.     

基于船位监控系统的拖网捕捞努力量提取方法研究

为了基于船位监控系统提取拖网捕捞努力量,通过统计航速获得3个峰值,拖网作业在第2个峰值,即1~2.1 m/s,拖网作业航向差一般在–50°~50°。利用航速、航向差阈值设定,把拖网船状态划分为慢速、作业、航行,然后提取出捕捞作业状态点,1 423艘拖网船共提取到处于捕捞状态的点318 433个,合计拖网捕捞时间15 921 h,利用反距离加权插值法生成捕捞强度分布变化趋势图。捕捞努力量在渔业资源研究中是重要的参考值之一,与传统的捕捞努力量计算方法相比,该方法具有实时、大范围、快速、分辨率高的特点,能够用于辅助渔业资源保护。     

Constraints on community participation in salmon fisheries management in Northwest Russia

Salmon fishing used to be the primary source of income in many rural areas of Arkhangelsk oblast in northwest Russia. People who settled in the area received a name Pomory, from Russian po moriu, meaning by sea, because their subsistence activities became marine fishing and hunting and seafaring. Local fisheries have undergone significant changes as post-Soviet Russia embraced the market economy and the state introduced fishing concessions. The current Russian law only allows fishing for salmon through officially registered recreational or commercial fisheries. Both these options are often either unavailable or unaffordable to rural dwellers, which leaves them with limited or no legal access to their traditional salmon fisheries. There has been a growing concern for protecting communities’ fishing rights among wider society in Arkhangelsk oblast. City activists promoted Pomory identity and appealed to the Russian government to grant Pomory an indigenous status to secure their access to fisheries. Although Pomor activism did not reach most of its proclaimed goals, it has contributed to promoting the image of Arkhangelsk oblast as a homeland to Pomor fishing. This image has played an important part in what Arkhangelsk authorities have called socially-oriented fisheries management. Officials have made good attempts to better accommodate rural communities’ access to fishing resources. Yet, these attempts have failed to include fishermen as active participants in the process. This paper looks at constraints on community participation in fisheries management in Russia. It considers both historical and contemporary reasons for the low participation of local community in fisheries management.     

Assessing potential spatial and temporal conflicts in Washington's marine waters

This paper uses spatial, temporal, and use-intensity data for 27 major marine uses in Washington waters to feature a method for assessing potential use conflicts in a variety of scenarios. The study represents a first step towards quantifying potential conflicts within Washington’s Marine Spatial Planning (MSP) study area by using a cumulative analysis to highlight high- and low-use intensity areas and the novel Marine Potential Conflict Index (MPCI), which incorporates space, time, and intensity of use, to quantify pairwise potential conflicts between uses. About 10% of pairs of uses do not overlap spatially and are likely compatible with one another. Temporally, the number of uses peaks in July and August and falls during January and February. Additionally, the MPCI identified three important use types with a substantial degree of potential conflict: commercial fishing, tribal fishing, and shipping. External data were used in three cases to ground-truth the analysis, as a limited test of its utility in managing any potential conflict. This article assesses the extent of Washington’s existing marine uses along spatial, temporal, and intensity axes, and more broadly provides a straightforward way to examine potential conflicts between marine uses.     

半潜平台浮子式系泊系统参数优化研究

通过在系泊缆中设置浮子可以改善系泊系统性能,降低平台运动响应。建立浮子式系泊系统的数值计算模型,验证浮子式系泊系统数值计算方法,详细分析浮子设计参数(设置位置和净浮力大小)变化对系泊缆张力特性与平台运动的影响规律,并根据得到的规律选择了优化的浮子系泊系统方案。最后对优化方案进行评估,表明优化方案可以显著降低系泊中的平台水平运动,尤其是低频运动,同时系泊缆张力变化不大,仍满足安全要求。研究结果可为今后浮子式系泊系统设计提供参考。     

垂荡式波浪能装置运动模型数值分析

垂荡式波浪能装置在海洋可再生能源开发中被广泛应用,通过浮子与摇杆在垂荡方向的相对运动吸收波浪能。在以往相关的运动预报数值分析中,通常基于微幅波假设,仅考虑浮子与摇杆在垂荡方向的运动,忽略摇杆其他自由度运动。建立并求解了垂荡式波浪能装置的非线性联合运动方程组,分析垂荡式波浪能装置的波浪载荷、浮子与平台连接处的受力情况。数值计算系统的运动响应,并将计算结果与已有的试验数据进行比较验证,结果表明数值模拟的垂荡式波能装置的运动响应与试验结果相符合。最后,应用本计算方法分析PTO(power take-off)参数对波能装置发电性能的影响。     

Numerical Investigation of Submarine Hydrodynamics and Flow Field in Steady Turn

This paper presents numerical simulations of viscous flow past a submarine model in steady turn by solving the Reynolds-Averaged Navier?Stokes Equations (RANSE) for incompressible, steady flows. The rotating coordinate system was adopted to deal with the rotation problem. The Coriolis force and centrifugal force due to the computation in a body-fixed rotating frame of reference were treated explicitly and added to momentum equations as source terms. Furthermore, velocities of entrances were coded to give the correct magnitude and direction needed. Two turbulence closure models (TCMs), the RNG model with wall functions and curvature correction and the Shear Stress Transport (SST) model without the use of wall functions, but with curvature correction and low-Re correction were introduced, respectively. Take DARPA SUBOFF model as the test case, a series of drift angle varying between 0° and 16° at a Reynolds number of 6.53×106 undergoing rotating arm test simulations were conducted. The computed forces and moment as a function of drift angle during the steady turn are mostly in close agreement with available experimental data. Though the difference between the pressure coefficients around the hull form was observed, they always show the same trend. It was demonstrated that using sufficiently fine grids and advanced turbulence models will lead to accurate prediction of the flow field as well as the forces and moments on the hull.     

南极长城站验潮站数据处理和潮汐特点初步分析

继在南极中山站建成我国南极首个永久性验潮站后,2012年1月在南极长城站又建成了我国南极第二个永久性验潮站。通过对长城站验潮站相关数据进行分析处理,得到了验潮基准系统的水准网平差结果和验潮仪零点标定结果,以及长城站附近海域海洋潮汐170个分潮的调和常数,并据此进行了潮汐预报,同时分析了长城站潮汐余水位的变化特征,探讨了利用附近的Antarctic Base Prat验潮站的余水位改正长城站潮汐预报的可行性,结果表明使用Antarctic Base Prat验潮站余水位改正长城站潮汐预报,可以显著提高长城站验潮站潮汐预报的精度,余水位改正后2014时段的潮汐预报中误差为±3.42 cm,明显好于改正前的预报中误差±10.43 cm。     

Integration of GIS and video surveillance

This paper discusses the integration of three-dimensional (3D) geographic information systems (GIS) and video surveillance systems using augmented reality (AR) techniques. The motivation for this integration is to overcome problems faced by conventional video surveillance systems. Explicit information concerning which camera currently monitors what area in such systems is missing; therefore, insight into the situation depends heavily on the operator’s training and experience. To ensure the complete coordination and monitoring of a situation in a system with multiple cameras, it is necessary to introduce a single reference system. GIS arises as a natural solution because it not only provides a solid ground truth but also provides semantic information that can be highly important in certain video surveillance applications. To integrate information into a GIS application, that information must be georeferenced. Based on our previous research regarding the addition of georeferencing information to surveillance video, this paper introduces models that can be applied to help integrate video and GIS. With an analogy to Milgram’s continuum between the real world and virtual reality, and analogous to the augmented reality and augmented virtuality in Milgram’s continuum, two models of integration are defined here: GIS-augmented video and video-augmented GIS. Then, we define the architecture of GIS-based video surveillance based on these proposed integration models, and finally, a prototype is implemented. The implemented prototype serves as a basis for analysing possible applications of real-world systems based on the integration of GIS and video.     

“To Understand the Place”: Geographical Knowledge and Diplomatic Practice

Diplomats produce a great deal of geographical knowledge: By reporting on distant places to their governments, they create particular understandings of political space. Yet these professionals rarely link their work to geography: What a geographer might call a geographical sensibility is labeled cultural knowledge by a diplomat. This article clarifies the relationship between geographical knowledge and diplomatic practice. Empirically, it draws from nearly 100 interviews with foreign policy professionals to offer a more “peopled” or quasi-ethnographic account of diplomacy than is usually available in scholarly literature. Conceptually, the article contributes to our understanding of how geographical knowledge is created inside diplomatic and bureaucratic institutions.