Modelling the long-term distribution of significant wave height with the Beta and Gamma models

The paper suggests modelling the long-term distribution of significant wave height with the Gamma, Beta of the first and second kind models. The three models are interrelated, flexible and cover the three different tail types of Extreme Value Theory. They can be used simultaneously as a means of assessing the uncertainty effects that result from choosing equally plausible models with different tail types. This procedure is intended for those applications that require the long-term distribution of significant wave height as input rather than the prediction of extreme values. The models are fitted to some significant wave data as an illustration. Details about maximum likelihood estimation are given in A.     

Seasonality and duration in extreme value distributions of significant wave height

This paper presents a statistical model to characterize the long-term extreme value distribution of significant wave height, conditioning to the duration of the storm and accounting for seasonality. A time-dependent version of the peak over threshold (POT) approach is used to build the model, which is then applied to specific reanalysis time series and NOAA buoy records. The model considers the annual and semiannual cycles which are parameterized in terms of harmonic functions. The inclusion of seasonal variabilities substantially reduces the residuals of the fitted model. The information obtained in this study can be useful to design maritime works, because (a) the model improves the understanding of the variability of extreme wave climate along a year and (b) the model accounts for the duration of the storm, which is a key parameter in several formulations for rubble mound breakwater design.     

Corporate-cooperative management of fisheries: A potential alternative governance structure for low value small fisheries?

While the economic and environmental benefits of fisheries management are well accepted, the costs of effective management in low value fisheries, including the research necessary to underpin such management, may be considerable relative to the total economic benefits they may generate. Co-management is often seen as a panacea in low value fisheries. Increasing fisher participation increases legitimacy of management decision in the absence of detailed scientific input. However, where only a small number of operators exist, the potential benefits of co-management are negated by the high transaction cost to the individual fishers engaging in the management process. From an economic perspective, sole ownership has been identified as the management structure which can best achieve biological and economic sustainability. Moving low value fisheries with a small number of participants to a corporate-cooperative management model may come close to achieving these sole ownership benefits, with lower transaction costs. In this paper we look at the applicability of different management models with industry involvement to low value fisheries with a small number of participants. We provide an illustration as to how a fishery could be transitioned to a corporate-cooperative management model that captures the key benefits of sole management at a low cost and is consistent with societal objectives.     

山东省滨海湿地生态价值评估

本文依据Google Earth近2年的遥感影像以及2013年的资源3号卫星影像数据,并结合他人前期研究资料,对山东省滨海湿地的分布和类型进行了研究,使用ArcGIS软件测算出滨海湿地总面积约为5 124km2,其中自然湿地占35.23%,人工湿地占64.77%。根据山东省湿地实际状况,以及湿地的地理位置、成因、水文、生物等要素的差异,将山东省滨海湿地划分为十种类型,并在此基础上,针对滨海湿地不同的生态服务功能类型,采取了不同的方法进行初步价值评估。结果表明,山东省滨海湿地生态服务总价值约3 303亿元,约占山东省2013年GDP的6.04%。其中物质生产价值约占总价值的50.70%,其次为环境调节价值,约占48.24%,社会服务价值只占1.06%。这表明,山东省滨海湿地蕴含较高的经济和生态潜力,能带来较高的经济效益和生态效益,但是社会服务功能价值量相对偏低,有待于进一步重视和开发。     

单点高频地波雷达资料估算潮能耗散的方法

使用嵊泗站所布设的地波雷达观测获取的径向流数据,以及嵊泗、芦潮港、岱山3个潮汐观测站水位资料,采用两点近似投影方法反演流场全矢量流速,并用T-Tide程序计算调和常数,分别计算O1、K1、M2、S2各分潮流速场及迟角场,并计算各点上的潮能通量及潮能耗散,得到嵊泗岛以西杭州湾口区域潮能耗散同地形存在良好对应关系,充分证明了采用地波雷达观测数据进行潮能耗散计算这一方法的可行性,供相关工作者作进一步研究和讨论.     

辽东湾东部区块热带风暴设计增水的计算

以辽东湾东部区块出现的极值增水序列为例,考虑热带气旋过程出现频次的影响,采用泊松-最大熵复合极值分布进行了增水统计分析,计算得到辽东湾东部区块的增水重现值.最大100年一遇值为183cm,最大50年一遇值为158cm,皆出现于第1区块.由于受地形的影响,区块1、2与3的增水大小相似,区块4则略小.该结果对辽东湾东部区块...     

日本蟳血细胞及血液生化指标的研究

以光镜和电镜观察了日本蝠（Charybdisjaponica）血细胞的形态结构,分析了各类血细胞的大小、数量比例及功能,并测定了不同发育时期及饥饿状态的日本蝽血清主要生化指标。结果表明：日本蝠血细胞可分为4种类型,从小到大依次为：无颗粒细胞、小颗粒细胞、中间型细胞和大颗粒细胞;其核质比分别为：53．23％、33．64％...     

计算数据域特征值的两种算法

设计两种计算数据域特征值的算法。此特征值通常是用线性反馈移位寄存器（ＬＦ－ＳＲ）组成的特征分析器得到的．在数据已按字节存放和速度要求不高的场合下，本算法将是十分方便和有用的．     

地震活动性参数b值和年发生率的一种取值方法

介绍了一种将历史地震与现代小震统计结果相协调,去不可靠或不稳定数据段确定地震活动性参数ｂ值,以及通过不同震级下限地震频度的时间滑动分析,选取现今与历史相近,且具较高震级下限的统计结果,推算４级以上地震年发生度ｖ４的方法。计算给出了东南沿海地震带及其南带,北带的ｂ值和ｖ４值。     

Deterministic sensitivity analysis for a model for flow in porous media

A deterministic method for sensitivity analysis is developed and applied to a mathematical model for the simulation of flow in porous media. The method is based on the singular value decomposition (SVD) of the Jacobian matrix of the model. It is a local approach to sensitivity analysis providing a hierarchical classification of the directions in both the input space and of those in the output space reflecting the degree of sensitiveness of the latter to the former. Its low computational cost, in comparison with that of statistical approaches, allows the study of the variability of the results of the sensitivity analysis due to the variations of the input parameters of the model, and thus it can provide a quality criterion for the validity of more classical probabilistic global approaches. For the example treated here, however, this variability is weak, and deterministic and statistical methods yield similar sensitivity results.