Deemed value arbitrage in the New Zealand annual catch entitlement market     

《Marine Policy》2016

New Zealand's Quota Management System (QMS) consists of a two tier operational structure: Quota shares in a fishstock provide an Annual Catch Entitlement (ACE) of the total allowable commercial catch (TACC) of the specific fishstock. Fishers operating in a multispecies fishery need a portfolio of ACE that matches the mix of their annual catch. Fishers may own quota shares, and thereby receive the needed ACE allocations or they may operate without quota shares and rely on acquiring ACE in the ACE market. Whatever the fisher's situation, it is common for fishers to both buy and sell ACE during a fishing year as they seek to balance their actual catch against ACE. The incentive to achieve a balance is strong because at year-end fishers whose catch exceeds ACE are required to pay a fee called ‘deemed value’. For many fishstocks the deemed value fee increases sharply as the percentage by which a fisher's catch exceeds their ACE increases. When no ‘unbalanced’ ACE is available for purchase, an overfished fisher may attempt to mitigate their deemed value liability by engaging in arbitrage trading in ACE whereby they buy ACE from other overfished fishers. This study examines the nature and extent of ACE arbitrage behaviour in the New Zealand quota managed fishery. The study finds that the number of fishstocks where arbitrage trading occurs is relatively small and is declining. However, sizeable deemed value mitigation transactions are still evident.  相似文献   

基于小波分析的海洋平台实时结构健康监测     

李晔 《海洋工程》2016,34(5):131-136

由于海洋平台结构长期处于恶劣的海洋环境中,并受到各种载荷的交互作用,结构容易产生各种形式的损伤。因此,对海洋平台进行实时监测有着十分重要的现实意义。以单筒简易导管架平台为例,主要在结构损伤的判定和定位两方面对海洋平台的实时结构健康监测进行研究,结果表明通过对结构响应信号进行小波分析,小波变换系数和小波包能量分布可以很好地定义损伤识别指标。  相似文献   

Characterizing the Seasonal and Directional Varying Properties in A Marine Environment     

张熠  程涛 《海洋工程》2016,(4):549-564

With noticing an increasing number of failure events for offshore structures in the present days, it is now realized that modeling the marine environment especially for exceptional environmental conditions is quite important. It is recognized that a possible improvement in the traditional modeling of environmental characteristics, which are the basis for the load models for structural analysis and design, may be needed. In this paper, the seasonal and directional varying properties in modeling the ocean parameter, the wave height, are studied. The peak over threshold (POT) method is selected to model the extreme wave height by utilizing a non-stationary discrete statistical extreme model. The varying parameters are taken into account with a changing pattern to reflect the seasonal and directional dependent behavior. Both the magnitude and the occurrence rate of the extreme values are investigated. Detailed discussion on the continuity of the established model is also given. The importance of the proposed model is demonstrated in reliability analysis for a jacket structure. The sensitivity to the changing marine environment in reliability analyses is investigated.  相似文献   

改进LM模型在机载小光斑LiDAR数据分解中的应用     

李鹏程  邢帅  王蓉  刘志青  张军军 《测绘科学技术学报》2016,(4):383-387

机载小光斑Li DAR是近年来遥感领域的新兴技术,它对回波脉冲进行全数字化的记录,通过分解返回波形能够得到更加丰富的信息。针对传统LM波形分解算法容易陷入局部最优的问题,引入改进LM模型,采用信赖域技巧使得参数解全局收敛。实验证明,该方法相比传统LM能够得到更加可靠的波形分解结果,并且对城区、郊区和山地区域适应性好,具有较强实用价值。  相似文献   

基于GPU的全波形并行LM分解算法     

张军军  邢帅  李鹏程  夏琴 《测绘科学技术学报》2016,(4):421-425

波形分解是机载激光雷达全波形数据处理的重要基础工作,通过求解波形函数模型的参数,将波形数据利用具体的函数模型拟合出来,实现对全波形及其中各个子波形函数表达。LM(Levenberg-Marquardt)算法及其改进的算法是波形分解中对参数进行拟合求解的常用方法。针对LM算法在参数拟合计算的过程中存在大量迭代和矩阵运算,提出了基于线程块组和线程两级并行粒度的并行计算方案。将串行多次循环迭代求解参数改为单次并行计算取最佳值实现对参数的选择,将矩阵运算进行线程块的协同并行计算,实现了LM算法在通用计算图形处理器上的并行计算。实验证明,在规定阈值条件下,并行LM降低了算法的迭代次数,提高了波形分解LM算法的计算效率,为提高波形分解的处理效率提供了研究思路。  相似文献   

Impact of Planetary Wave Reflection on Tropospheric Blocking over the Urals–Siberia Region in January 2008   总被引：1，自引：0，他引：1  

Debashis Nath  Wen Chen 《大气科学进展》2016,33(3):309-318

Planetary wave reflection from the stratosphere played a significant role in changing the tropospheric circulation pattern over Eurasia in mid-January 2008. We studied the 2008 event and compared with composite analysis(winters of 2002/2003,2004/2005, 2006/2007, 2007/2008, 2010/2011 and 2011/2012), when the downward coupling was stronger, by employing time-lagged singular value decomposition analysis on the geopotential height field. In the Northern Hemisphere, the geopotential fields were decomposed into zonal mean and wave components to compare the relative covariance patterns. It was found that the wavenumber 1(WN1) component was dominant compared with the wavenumber 2(WN2) component and zonal mean process. For the WN1 field, the covariance was much higher(lower) for the negative(positive) lag, with a prominent peak around +15 days when the leading stratosphere coupled strongly with the troposphere. It contributed to the downward coupling due to reflection, when the stratosphere exhibited a partially reflective background state. We also analyzed the evolution of the WN1 anomaly and heat flux anomaly, both in the troposphere and stratosphere, during January–March 2008. The amplitude of the tropospheric WN1 pattern reached a maximum and was consistent with a downward wave coupling event influenced by the stratospheric WN1 anomaly at 10 h Pa. This was consistent with the reflection of the WN1 component over Eurasia, which triggered an anomalous blocking high in the Urals–Siberia region. We further clarified the impact of reflection on the tropospheric WN1 field and hence the tropospheric circulation pattern by changing the propagation direction during and after the event.  相似文献   

黄石、大冶两邻近地区设计雨强差异的原因分析     

方怡  陈正洪  孙朋杰  陈幼姣  陈城 《气象》2016,42(3):356-362

利用水平距离约23.7 km、年降水量相近的黄石和大冶气象站多年分钟降水资料,根据相关规范,分别推算黄石、大冶两市暴雨强度公式各参数,并分析两市设计雨强存在差异的原因。结果表明:(1)根据公式推算结果,在重现期0.5~100 a黄石各历时雨强(5~120 min)均大于大冶,最大可达27.34%;(2)黄石平均年降水量略小于大冶,但最大年降水量、最大月降水量、最大日降水量、平均年暴雨日数均大于大冶的相应值;(3)对经过年多个样法选样后的降水量样本进行分析:除了第一个最大降水量的多年平均值黄石偏大,其余7个次大值大冶略大。黄石前8个最大降水量算出的标准偏差约为大冶的1.4倍。综合可见,短历时降水量的偏大是黄石设计雨强结果偏大于大冶的原因,设计雨强结果对样本的第一个最大雨量值以及标准偏差更为敏感。  相似文献   

辅助模型辨识方法(3):输入非线性输出误差自回归系统     

丁锋  毛亚文 《南京气象学院学报》2016,8(3):193-214

输入非线性系统包括输入非线性方程误差类系统和输入非线性输出误差类系统.针对输入非线性输出误差自回归系统,分别基于过参数化模型,基于关键项分离原理,基于数据滤波技术,研究了相应的基于过参数化模型的辅助模型递推辨识方法、基于关键项分离的辅助模型递推辨识方法、基于数据滤波的辅助模型递推辨识方法.这些方法可以推广到其他输入非线性输出误差系统、输出非线性输出误差系统、反馈非线性系统等.并给出了几个典型辨识算法的计算步骤、流程图和计算量.  相似文献   

辅助模型辨识方法(1):自回归输出误差系统     

丁锋 《南京气象学院学报》2016,8(1):1-22

研究了自回归输出误差(AR-OE)系统的辅助模型随机梯度算法、辅助模型多新息随机梯度算法、辅助模型递推最小二乘算法,自回归输出误差自回归滑动平均(AR-OEARMA)系统(即AR-Box-Jenkins系统)的辅助模型广义增广随机梯度算法、辅助模型多新息广义增广随机梯度算法、辅助模型递推广义增广最小二乘算法,以及AR-Box-Jenkins系统的基于滤波的辅助模型广义增广随机梯度算法、基于滤波的辅助模型多新息广义增广随机梯度算法、基于滤波的辅助模型递推广义增广最小二乘算法等.  相似文献   

同时改进背景值和初始条件的一种GM(1,1)预测方法     

章重阳  邹亚未  张飞 《测绘与空间地理信息》2016,(5)

传统GM(1,1)模型在背景值和初始条件的选取方面存在不足,为了提高灰色GM(1,1)模型的预测精度和拟合精度,本文提出了一种同时改进背景值和初始条件选取的新模型,此模型对以往单独对背景值或初始条件的优化进行了改进,将两个影响条件整合到一起。最后通过实例将该新模型与几种模型的拟合和预测数据比较,显示出了新模型的预测精度高。  相似文献