海杂波典型幅度分布模型的仿真分析

为改善舰载雷达目标检测的性能,对瑞利分布、对数正态分布、韦布尔分布和K分布四种典型海杂波幅度分布模型进行模拟仿真,分析了四种分布模型的特点规律,并采用海杂波实测数据,对模型进行拟合度检验,实验结果表明,K分布海杂波模型实用性广,能够在不同参数下描述多种海况的海杂波分布规律,为抑制海杂波提高目标检测性能提供了理论依据。     

航海雷达模拟中的海杂波建模及仿真

复合K分布统计模型能够很好的描述海杂波的幅值与相关性特征。通过建立海杂波幅度分布特征、时间相关性与空间相关性模型,利用球不变随机过程（SIRP）方法可以仿真时空相关K分布海杂波序列。在舰载导航搜索雷达系统模拟中应用该方法来模拟生成海杂波,能够逼真地表现海杂波随雷达环境的变化。仿真结果表明了该方法的有效性。     

基于ZMNL的相关复合K分布雷达海杂波仿真

相关K分布是一种适于描述雷达海杂波的非高斯分布模型。快速、准确地模拟雷达海杂波，对雷达最优信号处理器的设计及雷达系统的模拟是十分重要的。讨论了相关K分布海杂波的建模与仿真，在K分布的自相关函数与高斯分布的自相关函数之间的非线性关系的基础上，利用修正的零记忆非线性变换（ZMNL），仿真产生了相关复合K分布雷达海杂波。仿真实验结果表明，这种方法是准确、有效、可行的。     

一种相干复合高斯海杂波仿真方法

具有拖尾的复合高斯模型非常适于描述高分辨率海杂波,对雷达最优检测算法设计和雷达性能评估具有十分重要的意义。该文讨论了复合高斯模型海杂波的建模与仿真,并详述了产生Gamma随机过程的MNLT方法。产生了复合高斯模型的高海况条件下的海杂波,并与实测数据对比,表明了该方法的有效性和可行性。     

相关地杂波建模和仿真

分析了雷达地杂波的幅度和频谱分布特性,通过对大量实测地杂波回波数据的分析和拟合,建立了仿真杂波幅度和频谱特性的模型.地面杂波的相关特性可以用低阶AR模型很好地描述,而其幅度分布特性可以用对数正态分布建模.研究了基于零记忆非线性变换法对相关对数正态分布杂波的建模和仿真方法,仿真效果理想.这种方法快速、有效,可用于雷达信号模拟和雷达信号处理器的设计.     

线性调频脉冲压缩雷达地杂波的分布特性仿真

大量的实测数据表明,雷达杂波的统计分布特性明显偏离高斯分布.本文选取对数正态分布进行相关非高斯杂波的仿真.针对线性调频脉冲压缩雷达信号的波形特性,分析了其地杂波模型,给出了一种地杂波的模拟方法,并给出仿真结果,结果表明此法能有效的进行线性调频脉冲压缩雷达地杂波模拟.     

相参海杂波建模与建模和仿真研究

本文采用零记忆非线性变换法和球不变随机过程法对海杂波进行了建模和仿真研究,实现了相参Rayleigh分布、相参Weibull分布和相参K分布杂波的模拟,并对建模和仿真数据进行了检验,验证了建模和仿真方法的有效性。本次建模的特色之处在于考虑了杂波的相参性,并建立了三种杂波的概率分布模型和功率谱模型。     

地杂波后向散射系数经验模型研究

后向散射系数是地杂波性质研究中一个重要的概念,文章介绍了Ulaby后向散射系数和Kulemin后向散射系数经验模型,并且用上述两种经验模型对地面和草地的毫米波段实验数据进行了数据拟合,通过仿真证明上述两种经验模型与实测数据有很好的吻合性,可为毫米波雷达设计提供理论依据。     

海上导航雷达回波的数学模型研究及仿真

主要研究海上导航雷达回波的数学模型。首先,对导航雷达的基本功能构造进行了解;然后,利用雷达探测原理和相关数学知识分析海上雷达目标回波信号的功率密度计算方法,并分析雷达检测目标的灵敏度与目标距离雷达之间距离关系。最后,对满足Weibull分布的海杂波的数学模型进行分析,并通过仿真实验获取海杂波的幅度谱密度曲线。     

混沌时间预测方法的高分辨率雷达海杂波非线性分析

海洋运输业的发展对船载雷达的预测精度提出了更高要求。雷达收集信号中存在大量的海杂波噪声。由于海杂波具有动态性,传统的基于线性分析的模型不能提高目标分析的精度。本文针对海杂波的非线性特征,提出使用混沌时间方法分析海杂波,通过神经网络训练数据得到精确预测模型,提高雷达海杂波非线性分析的准确率。     

Errata

正In the paper"Influence of Fouling Assemblage on the Corrosion Behaviour of Mild Steel in the Coastal Waters of The Gulf of Mannar,India"in Vol.12,No.4,Page:509,References were lost,and the two authors’biographies were identical.The correct text is shown below.We apologize to the authors and our readers for any inconvenience caused by the errors.     

Journal of Marine Science and Application 2014 Sum. Contents

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第34届海洋、离岸及极地工程国际会议(英文)

正St.John's,Newfoundland,Canada,May 31-June 5,2015 OMAE2015 is the ideal forum for researchers,engineers,managers,technicians and students from the scientific and industrial communities from around the world to: meet and present advances in technology and its scientific support;     

联合作战计划和执行系统

全球指挥控制系统(GCCS)实施当前美国海军网络中心战信息基础设施的联合计划网络。联合作战计划和执行系统(JOPES)支持GCCS实现联合计划。JOPES有两类计划：时间不限的精密预案计划生成作战计划、方案计划或职能计划；时间敏感的危机行动计划生成作战命令或战役方案。前者在和平时期创建的作战计划是后者的计划基础，加速应付危机的能力。     

Eastbound or westbound ?

In terms of equal sailing distances, where is the inflexion when ships depart from ports in the Asian Continent to New York via Suez and/or Panama？
The answer is China South Port Group （Hong Kong, Shenzhen and Guangzhou）.     

Recent progress on wave induced loading measurements in warships

Recent measurements of wave induced hull strain and flexure in RN warships are presented together with the derivation of the current design criteria for extreme hull girder bending loads. The history of the development of the shipboard instrumentation used is given and recent developments to improve the quality and ease of analysis of the data are described. An unexpectedly high transverse asymmetry in the longitudinal strains measured in destroyers is shown to be the result of a combination of vertical and lateral bending in oblique seas. Finally recent theoretical comparisons between the loading of Deep-Vee hulls and conventional UK rounded bilge hulls are presented which demonstrate the higher loading experienced by this type of hull form.     

桥梁防撞设施物理模型试验

物理模型试验是预报防撞设施所受撞击力及优化设计方案的主要方法之一。结合杭州湾大桥柔性防撞设施及东海大桥独立式防撞体设计方案,阐述了船—防撞体撞击试验的基本原理、方法、试验方案及相关试验结果。提出了柔性防撞系统的优化方案。试验结果表明,该方案经济有效,可供预报类似桥梁防撞设施撞击力时参考。     

印尼某电厂码头水工建筑物设计

印尼某电厂项目码头水工建筑物包括码头、防波堤和护岸等主要组成部分。在该项目水工建筑物的设计过程中,综合考虑当地的自然条件、施工能力和材料来源等因素,不断优化结构选型和结构断面。根据不同使用要求,护岸分别采用直立式和斜坡式2种结构型式,推荐的设计方案节省投资、施工方便,可供同类工程设计参考。     

Impact of regulation on the performances of long-distance transport services: A comparison of the different approaches in Sweden and Norway

Despite the many socio-economic similarities between Sweden and Norway, differences in jurisdiction, organisation, cooperation, and financing of long-distance passenger train and coach services have led to the development of four distinctively different ways of serving the markets. This paper describes how the train and coach markets have developed in the two countries, with emphasis on regulatory and industrial structure and a couple of performance variables.Looking at passenger rail, both countries separated infrastructure from operation over a decade ago. However, while Norwegian rail is characterised by an almost monopoly supplier, rail services in Sweden are partly decentralised to the responsibility of county authorities and are widely subjected to competitive tendering. The rest of the network is about to be opened up for on-the-track competition. Swedish Rail (SJ) has spent the last decades consolidating its core business (passenger rail) and sold out its other businesses. In contrast, the Norwegian state rail (NSB) has expanded its business to become a major bus operator and property owner, with extensions also into the Swedish market.The coach industry was more recently deregulated in both countries. The Swedish coach market is dominated by privately owned companies operating services to and from Stockholm. In Norway, state-owned NSB is a major coach operator on medium distance routes, and is also the largest partner of Nor-Way Bussekspress which totally dominates long-distance coach services. Further, the Norwegian coach market is characterised by cross-ownership and cooperation which has enabled an extensive route network which covers most of Norway.We find distinct differences in achievements in the two modes and in the two countries. Swedish rail services have succeeded in winning market shares and in renewing and developing both infrastructure and service levels to a greater extent than the Norwegian model. On the other hand, the Norwegian coach market seems to be more developed and efficient compared to its Swedish counterpart.The paper concludes with a discussion on the possible links between the different approaches and the performance observed, with the aim to stimulate further and more detailed research on some important issues.     

开放式数据挖掘系统模型

目前国内已经出现了少量的数据挖掘相关产品。国内数据挖掘软件无论从数量还是质量上比较，都与国外软件存在着较大的差距。随着数据仓库技术的普及，数据挖掘应用的需求越来越强烈，如何缩短这种差距，研发数据挖掘软件产品成为国内业界的一个重要问题。通过引用目前国际通用数据挖掘标准技术来构建开放式的数据挖掘系统模型，该系统模型从可扩展性、可重用性、易用性等方面得到了加强。