SoFISHticated policy – social perspectives on the fish conflict in the Northeast Atlantic     

《Marine Policy》2016

Ecosystem changes currently question the traditional allocation of fishing rights and quotas in the fishery of Northeast Atlantic mackerel and Norwegian spring-spawning herring in the Northeast Atlantic. Variability in the distribution of these highly migratory species escalated in a political conflict between member states of the European Union, Iceland, the Faroe Islands and Norway, which is a driving force for unsustainable fishery. The aim of this paper is to investigate this conflict by outlining the social understandings of diverse stakeholders by using the Q methodology. The method reduced the complexity of numerous opinions, detected four distinct perspectives and simultaneously categorised the participating stakeholders. Although the perspectives differ in various elements, the protection of economic interests seems to dominate over the quest for sustainability. The call of all stakeholders in this study to clarify the fishing rights in the Northeast Atlantic reveals a clear deficiency of the current international fishery management in handling abrupt ecological changes and the necessity to acknowledge this as a complex adaptive system.  相似文献   

The Marine Planning Framework for South Australia: A new ecosystem-based zoning policy for marine management     

Val Day  Rosemary PaxinosJon Emmett  Alison WrightMeg Goecker 《Marine Policy》2008

The Marine Planning Framework for South Australia is a new large-scale, ecosystem-based zoning policy for management of development and use in the marine environment. Utilising the Geographic Information System (GIS), the model establishes four ecologically rated zones, derived from known ecological criteria. A series of goals, objectives and strategies represent the desired outcomes for each of the ecologically rated zones. A Performance Assessment System (PAS) will subsequently evaluate the success of the marine plans. Implementation will be supported by a collaborative whole-of-government approach. Marine plans will facilitate the delivery of long-term protection to the marine environment as a whole ecosystem, whilst enabling a broad range of activities to occur in a sustainable manner.  相似文献   

Landslide susceptibility modeling based on ANFIS with teaching-learning-based optimization and Satin bowerbird optimizer   总被引：1，自引：0，他引：1  

Wei Chen  Xi Chen  Jianbing Peng  Mahdi Panahi  Saro Lee 《地学前缘(英文版)》2021,12(1):93-107

As threats of landslide hazards have become gradually more severe in recent decades,studies on landslide prevention and mitigation have attracted widespread attention in relevant domains.A hot research topic has been the ability to predict landslide susceptibility,which can be used to design schemes of land exploitation and urban development in mountainous areas.In this study,the teaching-learning-based optimization(TLBO)and satin bowerbird optimizer(SBO)algorithms were applied to optimize the adaptive neuro-fuzzy inference system(ANFIS)model for landslide susceptibility mapping.In the study area,152 landslides were identified and randomly divided into two groups as training(70%)and validation(30%)dataset.Additionally,a total of fifteen landslide influencing factors were selected.The relative importance and weights of various influencing factors were determined using the step-wise weight assessment ratio analysis(SWARA)method.Finally,the comprehensive performance of the two models was validated and compared using various indexes,such as the root mean square error(RMSE),processing time,convergence,and area under receiver operating characteristic curves(AUROC).The results demonstrated that the AUROC values of the ANFIS,ANFIS-TLBO and ANFIS-SBO models with the training data were 0.808,0.785 and 0.755,respectively.In terms of the validation dataset,the ANFISSBO model exhibited a higher AUROC value of 0.781,while the AUROC value of the ANFIS-TLBO and ANFIS models were 0.749 and 0.681,respectively.Moreover,the ANFIS-SBO model showed lower RMSE values for the validation dataset,indicating that the SBO algorithm had a better optimization capability.Meanwhile,the processing time and convergence of the ANFIS-SBO model were far superior to those of the ANFIS-TLBO model.Therefore,both the ensemble models proposed in this paper can generate adequate results,and the ANFIS-SBO model is recommended as the more suitable model for landslide susceptibility assessment in the study area considered due to its excellent accuracy and efficiency.  相似文献   

Nonlinear adaptive control of an underwater towed vehicle     

Francisco Curado Teixeira  António Pedro Aguiar 《Ocean Engineering》2010,37(13):1193-1220

This paper addresses the problem of simultaneous depth tracking and attitude control of an underwater towed vehicle. The system proposed uses a two-stage towing arrangement that includes a long primary cable, a gravitic depressor, and a secondary cable. The towfish motion induced by wave driven disturbances in both the vertical and horizontal planes is described using an empirical model of the depressor motion and a spring-damper model of the secondary cable. A nonlinear, Lyapunov-based, adaptive output feedback control law is designed and shown to regulate pitch, yaw, and depth tracking errors to zero. The controller is designed to operate in the presence of plant parameter uncertainty. When subjected to bounded external disturbances, the tracking errors converge to a neighbourhood of the origin that can be made arbitrarily small. In the implementation proposed, a nonlinear observer is used to estimate the linear velocities used by the controller thus dispensing with the need for costly sensor suites. The results obtained with computer simulations show that the controlled system exhibits good performance about different operating conditions when subjected to sea-wave driven disturbances and in the presence of sensor noise. The system holds promise for application in oceanographic missions that require depth tracking or bottom-following combined with precise vehicle attitude control.  相似文献   

Multi-variable adaptive back-stepping control of submersibles using SDU decomposition     

Pradeep R. Nambisan 《Ocean Engineering》2009,36(2):158-167

A multi-variable adaptive autopilot for the dive-plane control of submarines is designed. The vehicle is equipped with bow and stern hydroplanes for maneuvering. It is assumed that the system parameters are not known, and the disturbance force is acting on the vehicle. Based on a back-stepping design approach, an adaptive control law is derived for the trajectory control of the depth and the pitch angle. To prevent singularity in the control law, the SDU decomposition of the high-frequency gain matrix is used for the design. In the closed-loop system, asymptotic tracking of the reference depth and pitch angle trajectories is accomplished. Simulation results are presented which show that the submarine performs dive-plane maneuvers in spite of the uncertainties in the system parameters and disturbance forces.  相似文献   

Alternative Fuzzy Cluster segmentation of remote sensing images based on Adaptive Genetic Algorithm     

Jing Wang  Jilong Tang  Jibin Liu  Chunying Ren  Xiangnan Liu  Jiang Feng 《中国地理科学(英文版)》2009,19(1):83-88

Remote sensing image segmentation is the basis of image understanding and analysis. However, the precision and the speed of segmentation can not meet the need of image analysis, due to strong uncertainty and rich texture details of remote sensing images. We proposed a new segmentation method based on Adaptive Genetic Algorithm (AGA) and Alternative Fuzzy C-Means (AFCM). Segmentation thresholds were identified by AGA. Then the image was segmented by AFCM. The results indicate that the precision and the speed of segmentation have been greatly increased, and the accuracy of threshold selection is much higher compared with traditional Otsu and Fuzzy C-Means (FCM) segmentation methods. The segmentation results also show that multi-thresholds segmentation has been achieved by combining AGA with AFCM.  相似文献   

大地电磁自适应正则化反演算法   总被引：36，自引：11，他引：36       下载免费PDF全文

陈小斌  赵国泽  汤吉  詹艳  王继军 《地球物理学报》2005,48(4):937-946

针对大地电磁正则化反演中正则化因子的选取困难问题提出了自适应正则化反演算法（Adaptive Regularized Inversion Algorithm, ARIA）. 在该算法中， ①提出了一种新的数据方差处理方法：数据方差规范化，使得数据方差的大小只对数据的拟合发生影响，不对数据目标函数和模型约束目标函数的权重产生影响，从而减少了正则化因子取值的影响因素；②提出了粗糙度核矩阵的概念，并给出了由基本结构插值基函数计算粗糙度核矩阵的公式，使得模型目标函数的构建更为简便、直接；③根据数据目标函数、模型约束目标函数和正则化因子之间的关系，提出了两种正则化因子自适应调节方法. 本文详细阐述了最平缓模型约束下的大地电磁一维连续介质反演的ARIA实现，以几个算例的分析比较来说明ARIA的有效性.  相似文献   

Time, idealisation and international development: promoting Canadian co-management in northern Russia     

Elana Wilson 《Area》2007,39(3):323-330

In this article, I trace the efforts of a development team working to promote a Canadian approach to natural resources management in the Russian North. These development workers used two communication strategies related to time and history to render Canadian knowledge mobile and applicable to a new location: (1) imagining today's Russian North as equivalent to the Canadian northern past and (2) reframing and idealising the Canadian past and present to make the governance export less discursively 'messy' for an outside audience. The relative failure of these communicative strategies points to the need for richer dialogue in efforts to move knowledge cross-culturally.  相似文献   

An adaptive capacity spectrum method for assessment of bridges subjected to earthquake action     

Chiara Casarotti  Rui Pinho 《Bulletin of Earthquake Engineering》2007,5(3):377-390

Estimating seismic demands on structures, to predict their performance level with confidence, requires explicit consideration of the structural inelastic behaviour: to this end, the use of nonlinear static procedures is inevitably going to be favoured over complex nonlinear time-history methods. The currently available assessment procedures have been tested predominantly against building frames. A newly derived assessment procedure is proposed within the scope of bridge applications, based on an innovative displacement-based adaptive pushover technique. The procedure, which can be incorporated into a performance-based engineering philosophy, is applicable to MDOF continuous span bridges with flexible or rigid superstructures, and for varying degrees of abutment restraint. As a first application to determine the viability of the proposed procedure, a parametric study is conducted on a ensemble of bridges subjected to earthquake motion. It is shown that, compared to the seismic demand estimated by means of the more accurate nonlinear dynamic analysis tool, the novel static assessment method can lead to the attainment of satisfactory predictions, both in terms of displacement as well as moment demand on members.  相似文献   

A spatially and temporally adaptive solution of Richards’ equation     

Cass T. Miller  Chandra Abhishek  Matthew W. Farthing 《Advances in water resources》2006

Efficient, robust simulation of groundwater flow in the unsaturated zone remains computationally expensive, especially for problems characterized by sharp fronts in both space and time. Standard approaches that employ uniform spatial and temporal discretizations for the numerical solution of these problems lead to inefficient and expensive simulations. In this work, we solve Richards’ equation using adaptive methods in both space and time. Spatial adaption is based upon a coarse grid solve and a gradient error indicator using a fixed-order approximation. Temporal adaption is accomplished using variable order, variable step size approximations based upon the backward difference formulas up to fifth order. Since the advantages of similar adaptive methods in time are now established, we evaluate our method by comparison with a uniform spatial discretization that is adaptive in time for four different one-dimensional test problems. The numerical results demonstrate that the proposed method provides a robust and efficient alternative to standard approaches for simulating variably saturated flow in one spatial dimension.  相似文献