加权关联规则的改进算法

关联规则挖掘在许多领域已有广泛的应用,目前存在许多发现关联规则的算法,但这些算法都认为项目对规则的重要性相同.然而在现实中各个项目的重要性往往不同,决策者往往优先考虑利润较高的项目,而忽略利润较低的项目.分析现有的加权关联规则存在的问题,提出了一种新的加权关联规则模型.     

海上目标多源轨迹数据关联综述

船舶自动识别系统、船舶远程识别与跟踪系统、卫星导航定位系统、导航雷达、星载雷达等海上目标监控系统互相补充,极大地增加了海上移动目标监控的广度和质量。然而,同一个移动目标在不同系统中具有不同的标识和轨迹,需要进行有效的数据融合,关联多源轨迹数据,建立各系统中移动目标的对应关系,才能形成统一的海上态势,为移动目标跟踪、轨迹数据挖掘等提供支持。本文介绍和总结了海上目标多源轨迹的常见数据源;剖析与比较了可用于移动轨迹数据关联的最近邻、概率数据关联、联合概率数据关联和多假设跟踪4种量测/航迹关联方法,和基于统计方法或模糊数学的2类航迹/航迹关联方法,以及相关工作进展;总结了常见的算法评估方式;最后讨论了现有方法适用场景问题,及其进一步的研究方向。     

视觉辅助下的室内惯导位姿修正

惯性导航系统可以短期内提供连续的高精度信息,但是误差会随时间增大,不能长期独立工作。而在大型仓库、地下停车场等室内卫星信号薄弱的场景中,传统的惯导+卫星组合方法也不再适用。针对该问题,本文提出了一种视觉与惯导组合定位的方法。本文研究的惯导+视觉组合的定位方法中,采用基于合作目标的单目视觉定位方法对惯导误差进行修正。对于惯导误差的修正方法,本文利用视觉定位的位姿信息建立量测方程,进行卡尔曼滤波,并选取合适的试验设备,通过实际试验对比验证了该算法对惯导系统误差的修正具有良好的效果。     

浅谈地理国情监测与1∶10 000省级基础测绘数据更新

地理国情监测和1∶10 000省级基础测绘数据更新存在一定的差异,但同时也存在紧密的联系。本文从定义以及生产工艺两方面分析了二者之间的区别和联系,并初步探讨了利用两者之间的联系,实现地理国情监测与1∶10 000省级基础测绘数据协同更新的可行性和不可行性。     

协同主动学习和半监督方法的海冰图像分类

海冰遥感光谱影像分类中标签样本难以获取,导致海冰分类精度难以提高,但是大量包含丰富信息的未标签样本却没有得到充分利用,针对这种情况,提出一种协同主动学习和半监督学习方法用于海冰遥感图像分类。在主动学习部分,结合最优标号和次优标号、自组织映射神经网络以及增强的聚类多样性算法来选择兼具不确定性和差异性的样本参与训练;在半监督学习部分,利用直推式支持向量机,并且融合主动学习思想从大量未标签样本中选取相对可靠且包含一定信息量的样本进行迭代训练;然后协同主动学习分类结果和半监督分类结果,通过一致性验证保证所加入伪标签样本的正确性。为了验证方法的有效性,分别采用巴芬湾地区30 m分辨率的Hyperion高光谱数据(验证数据为15 m分辨率的Landsat-8数据)和辽东湾地区15 m分辨率的Landsat-8数据(验证数据为4.77 m分辨率的Google Earth数据)进行海冰分类实验。实验结果表明,相对其他传统方法,该协同分类方法可以在只有少量标签样本的情况下,充分利用大量未标签样本中包含的信息,实现快速收敛,并获得较高的分类精度(两个实验的总体精度分别为90.003%和93.288%),适用于海冰遥感图像分类。     

Impacts of unconstrained effort: Lessons from a rock lobster (Jasus edwardsii) fishery decline in the northern zone management region of South Australia

The Northern Zone rock lobster fishery of South Australia is expansive, covering an area of ∼207,000 km². From 1970 to 2002 it was managed under input controls that relied heavily on restrictions to days-at-sea and size limits. In 2003, output controls in the form of individual transferable quotas with a total allowable commercial catch were also introduced. Fishery performance from 1980 to 2007 was analysed based on catch data and model outputs. Trends in catch and effort increased through the 1980s and 1990s while nominal catch rate remained relatively stable. However, from 1999 to 2003 catch decreased by 49% from 1001 to 503 ton and has remained at <500 ton since. Importantly, nominal effort did not decline comparatively, decreasing by only 12% from 1999 to 2007. Consequently, nominal catch rate decreased by 47.5% from 1.43 to 0.75 kg/potlift, over the same period. Logbook data revealed strong evidence of spatial expansion through the 1980s and 1990s which is likely to have masked declining lobster abundance and contributed to a “hyperstability” scenario in catch rates. It is suggested that increasing effective effort, driven by advances in fishing technology and vessel design, fuelled this expansion. Model outputs, which account for increases in effective effort, indicate that biomass has decreased by ∼68% since the 1980s. The results highlight the limitations associated with input controls in controlling effort during periods of spatial expansion. Further evidence from puerulus settlement data stresses the importance of conservative quotas for lobster fisheries where annual recruitment is low or highly sporadic.     

Pyramids and roses: Alternative images for the governance of fisheries systems

Governors always have some image of what they are governing and why, and of what their role is. These images are often implicit. They are not reflected upon or discussed in the governance process, yet they have real consequences because they are acted upon. Interactive governance theory argues that image formation is an integral part of governance and that images are made as explicit as possible to avoid self-fulfilment. Such a process needs to be interactive and flexible to allow exploration of alternatives to existing governing images for the purpose of enhancing the governability of fisheries systems. In this paper, we contrast the classical image of the governing system (top down decision-making pyramid) and of the human-in-nature system (top down trophic pyramid) with alternative images (roses and inverted pyramid, respectively) and discuss the implication that these different images have on fisheries governance.     

Marine protected areas in Japan: Institutional background and management framework

Information on the location and area for all MPAs in Japan was collected through a comprehensive survey targeting government officials and local stakeholders. It was verified that at least 1161 MPAs exist in Japan. Of these, 1055 are implemented in conjunction with fishery regulations in the form of no-take zones. More than 30% of the individual MPAs in Japan were established by self-imposed instruments agreed by members of fishery co-management organizations. It was suggested that the autonomous MPAs are not a product of simple altruism, but rather are logical extensions of the tenure system guaranteed by the government legal system.     

Keeping the lead: How to strengthen shark conservation and management policies in Canada

Internationally, shark conservation is now being recognized as a major environmental challenge, but management efforts to halt the overexploitation of sharks have lagged behind. This review examines the state of knowledge for shark species in Canadian waters and analyzes the role of existing management and legislation in ensuring shark conservation. Despite Canada's early leadership, the present management framework reveals major shortcomings with regard to legal protection, bycatch and finning regulations. These problems are not unique to Canada but illustrate broader issues pertaining to the global management of endangered fish species. To strengthen the conservation and management of sharks, this paper recommends a set of key policies and management priorities, which exemplify proper precautionary management of endangered shark species in Canada and could serve as a blueprint for improving conservation efforts internationally. A structured approach for grading progress in shark conservation efforts against best practices is also presented and could be used as a goalpost elsewhere.     

Precious coral fisheries management in Taiwan—Past,present & future

Taiwan used to have the biggest precious coral fisheries industry in the world. However, due to changes in the fishery, including increased fishing restrictions and the replacement of obsolete vessels, the scale of the industry had been gradually reduced since 1979. Unfortunately, the initiative proved to be poorly managed and resulted in an increase in illegal, unreported and unregulated (IUU) coral fishing. This forced the government to review and amend the precious coral fisheries management regulations, which had been in place for decades. The Taiwanese government introduced stringent monitoring, control and surveillance (MCS) management methods, already used in deep water fisheries, as a precautionary approach. At the same time, an investigation and evaluation of existing resources was carried out. Together, these initiatives were introduced in order to encourage the domestic industry to adopt the concept of ecosystem-based fishery management.