DS-UWB通信系统的信号兼容性分析

采用超宽带(UWB)技术的无线通信系统,在实现对无线电频谱资源的充分利用的同时,也成为传统窄带系统的一种潜在干扰源.首先,通过对直扩超宽带(DS-UWB)信号功率谱密度的研究,分析了DS-UWB对典型窄带系统的干扰.其次,研究了DS-UWB信号功率谱密度的典型包络形式,已调信号功率谱的连续、离散成分和脉冲重复频率(PRF)对信号功率谱的影响,进而提出并讨论了合理设计伪码形式和选择PRF参数以减轻干扰影响的初步方案,最后讨论了DS-UWB与受扰系统的共存性.     

超宽带对卫星通信业务的干扰分析

针对超宽带（UWB，Ultra Wide Band）设备对窄带无线业务的干扰，通过对UWB空间分布进行投影和方位加权，提出一种新的三维投影干扰分析模型。该模型适于分析UWB设备对高增益、强方向性受扰设备干扰。在此模型基础上分析UWB对卫星通信业务的干扰，通过仿真得出了C波段卫星通信业务对UWB的使用限制。     

UWB技术在船舶避碰系统中的应用

在NLOS环境下分析了超宽带（UWB）信号及信道传输特性,针对信号的传播特性给出了UWB信号应用于船舶避碰的工作原理,确定合适的接收设备以实现信号的可靠接收,从而对两船之间的距离及方向进行实时监测,使工作人员根据判断结果采取一定的避碰措施,保证船舶航行安全.     

基于驿站节点的船舶机舱监测系统设计

针对船舶机舱监测系统信号传输过程中干扰源较多、干扰强度较大等特点,提出一种基于CAN冗余总线的船舶监测报警系统.在此基础上,根据船舶机舱可多路径敷设电缆的特点,提出了异地敷设总线的方法,提升了信号传输的可靠性;在总线接口处,引入驿站节点的思想,将有效信号发送至下一个环节并消除无效干扰,提升了信号传输的速度和效率.最后,通过数学方法证明了其有效性.     

码辅助技术抑制直扩系统数字窄带干扰性能

直扩系统在共道信道中的优越性使其在无线通信系统中得到广泛应用，而强窄带干扰的出现严重影响直扩系统性能。数字窄带干扰不同于准确定性窄带干扰和熵窄带随机过程，是一种新型窄带干扰，码辅助技术（Code-aidedtechn iques）是抑制这种窄带干扰的新途径。通过仿真，研究比较MMSE码辅助检测技术、解相关码辅助检测技术和匹配滤波检测技术在抑制直扩系统数字窄带干扰性能上的差异，总结得出MMSE码辅助检测技术是解相关码辅助检测技术和匹配滤波检测技术的折衷，但在抑制窄带干扰的情况下并无差异的重要结论。     

非高斯噪声背景下船舶轴频电场信号的提取

为了保证测量效果,采用窄带滤波对船舶轴频电场信号进行预处理,在此基础上,建立基于BP神经网络自适应噪声抵消系统对船舶轴频电场信号进行提取.     

脉冲多普勒雷达干扰技术研究

在对脉冲多普勒雷达干扰技术进行仿真研究的基础上,描述了脉冲多普勒雷达的数学模型,建立了对脉冲多普勒雷达的抗窄带噪声压制式干扰的干扰模型,说明了窄带噪声对雷达距离跟踪系统和速度跟踪系统的影响,分析了脉冲多普勒雷达的距离欺骗干扰和速度欺骗干扰,并建立了干扰模型.     

船载智能天线通信系统中干扰抑制技术

智能天线技术又叫自适应天线阵列技术,其核心在于阵列信号处理技术,最早应用于雷达和舰船声呐探测等领域,19世纪70年代逐渐被应用于军事通信领域。随着船舶领域的自动化和智能化发展,智能天线通信系统在船舶领域的应用越来越广泛。本文研究的主要对象是智能天线通信系统在船舶领域的应用问题,重点研究了智能天线系统的信号过滤和干扰抑制技术,分别从自适应抑制原理和干扰抑制系统的硬件进行介绍,本文的研究对改善船载智能天线通信系统的信号精度有重要的意义。     

基于北斗卫星的航行数据导航方法研究

针对北斗卫星在船舶导航中的应用方法进行研究。首先对北斗卫星系统在船舶导航应用中的系统构成和定位原理进行分析;然后针对由于测量误差的干扰造成信号载波相位错误而导致的定位精度下降问题研究多频载波的组合方式以减少误差干扰;最后将获取到的船舶位置坐标经过变换在电子海图上进行显示,实现船舶导航。     

船舶强噪声电子电力设备微弱故障信号获取系统

故障信号获取在船舶电子电力设备故障检测中具有重要作用,获取的故障信号质量越高,检测结果越好。为此,针对传统故障信号获取系统在面对强噪声干扰下,采集到的信号质量较差的问题,研究一种强噪声下船舶电子电力设备微弱故障信号获取系统。该系统在软件程序指导下,利用传感设备、通信设备以及DSP实现信号采集、处理、传输、分析、显示等功能。经测试,面对强噪声干扰,本系统采集到电子电力设备微弱故障信号信噪比要大于传统系统,由此说明本系统获取的信号质量更高,更有利于设备故障检测。     

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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33rd International Conference on Ocean,Offshore and Arctic Engineering （OMAE2014）

正San Francisco,California,June 8-13,2014.OMAE 2014 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;·to exchange ideas and experiences whilst promoting technological progress and its application in industry·to promote international cooperation in ocean,offshore and arctic engineering.In line with the tradition of excellence of previous OMAE conferences,more than 900 technical papers are planned for presentation.Outreach for Engineers Specialty Forum This Specialty Forum is designed for students and professionals who may not be familiar with the Ocean and Offshore industry,as well as those who have just recently specialized in this field.     

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。     

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.     

The 11th International Conference on Hydrodynamics (ICHD 2014)

正19–24 October 2014 SingaporeCONFERENCE THEMES The overall aim of the ICHD Conference is to provide a forum for participants from around the world to review,discuss and present the latest developments in the broad discipline of hydrodynamics and fluid mechanics.The first International Conference on Hydrodynamics(ICHD)was initiated in 1994 in Wuxi,China.Since then,9 more ICHD conferences were held subsequently in Hong Kong,Seoul,Yokohama,Tainan,Perth,Ischia,Nantes,Shanghai and St Petersburg.Evidently the ICHD conference has become an important event among academics,researchers,engineers and operators,working in the fields closely related to the science and technology of hydrodynamics.The 11th ICHD will be held in Singapore in 2014.     

第十二届深水操作会议和展览会(英文)

正November 4-6,2014Moody Gardens HotelConvention Center/Galveston,TX The Deepwater Operations Conference and Exhibition is celebrating its 12th anniversary this year.This growing event will continue the tradition of excellence in addressing operational challenges involved in developing deepwater resources.We will return to the Moody Gardens Hotel and Convention Center on November 5-7,2014 in Galveston,Texas.     

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）.     

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.     

某海港码头的撞损修复

依据码头撞击受损区域调查检测结果,对受损构件提出合理的修复方案,为码头的安全运行提供保障。