基于DSP6711的OFDM技术编解码实现

基于浮点数字信号处理芯片DSP6711,采用软件无线电方法构建一个基本的OFDM通信系统。在用MATLAB语言对该通信系统进行仿真的基础上,完成了CCS2．1软件平台上的由DSP硬件组成的OFDM系统C语言编程和运行通过;并利用Matlab所建立的仿真信道对此OFDM系统的编解码性能进行了测试。结果表明,论文所建立的编解码实现方案对高斯衰落信道具有一定的对抗性。     

基于软件无线电技术的高速水声通信实验系统设计

水声信道的频带极其有限和多径干扰严重是目前制约水声通信数据率提高的主要瓶颈。正交频分复用(OFDM)技术因具有抗多径干扰和频谱利用率高等特性而被大量通信标准采用。同时,软件无线电技术可简化系统的硬件结构、节省成本且便于升级。结合两种技术的优势,设计了一种基于软件无线电技术的高速水声通信系统。论文详细描述了系统框架、软硬件设计和信号处理流程。最后通过水声实验,验证了该系统具有可靠的传输性能。     

地基无线电导航标准现状及标准体系

地基无线电导航是以设置在陆地上的导航台为基础,通过无线电信号向飞机、船只、车辆或其他用户提供导航信息的系统。对地基无线电导航系统现有标准进行了梳理,在此基础上,通过分析地基无线电导航技术发展趋势,给出了一种地基无线电导航标准的体系结构,并对地基无线电导航制定的标准给出了意见和建议。     

一种基于正交频分复用的高速水声通信技术的研究

OFDM(正交频分复用)是一种适合于在多径衰落和受限带宽信道中进行高速传输的技术。论文把OFDM技术应用于高速水声通信中,设计了一套基于OFDM的高速水声通信系统,阐述了OFDM水声通信系统中同步和信道估计的方法。海上试验证明了系统的有效性。     

一种近海目标定位数据处理软件

本文介绍了一种近海目标定位数据处理软件的功能和操作方法,以及软件的结构与控制流程并给出了一个应用实例。     

多波束数据处理软件的应用与启示

介绍了目前国内多波束系统后处理软件的使用现状，阐述了CARIS HIPS软件的工作环境和特点，详细介绍了CARIS HIPS软件工作流程，最后简述了应用该软件得到的几点启示，在软件设计方面为我国自行研制开发多波束系统后处理软件提出了有益的建议。     

ARGOS LUT运行软件的分析与改进：（一）数据收集模块的分析与改进

我国在1986年引进的ARGOS系统地面站(VHF LuT)只能接收 NOAA—10及其前卫星转发的信息,无法接收1988年秋发射的、改变了传输格式的 NOAA—11转发的信息。为了解决这个问题,本文对 LUT 原有软件的“数据收集模块”进行了深入的分析,比较了 NOAA—10与 NOAA—11传输的数据,找出了其中的规律,并据之改进了原来的机器语言代码程序,使现有的 LUT 也能接收 NOAh—11转发的信息.这项成果不仅可供目前国内其它 LUT 工作人员参考,而且为今后分析 NOAA 系列卫星新的数据传输格式摸索了路子。     

海洋预报自动化填图系统

本软件是气象预报部门ＶＳＡＴ通讯小站下的气象填图自动化软件，它与卫星通讯软件相配套组成自动化填图系统，主要服务干各气象预报部门。     

海洋环境数值预报资料,产品的处理传输系统

本文根据海洋环境数值预报的特点，建立了资料、产品的处理系统以及远程数值传输通信系统，针对 同用户提出了几种数据传输方案，该系统建立在现有的成熟软件作基础上，具有使用方便、成本低、便于推广的特点。近几年投入海冰数值预报业务使用，取得了较好的效果。     

我记得你的脸

技术让罪犯愈发无处可藏。最近，英国肯特大学的研究者们在光学协会的年会上展示了一种被称为“EFIT—V系统”的软件。目前，这种软件已经被英国的15个警察部门使用，其他6个欧洲国家（包括法国和瑞士）也在使用这种软件。该软件可以用不断变化调整的脸部图像去贴近证人的记忆。     

四种重金属对刺参幼参的急性致毒效应

采用静水试验法,在水温18.5℃~20℃的条件下,用Cu2 ,Zn2 ,Cd2 和Cr6 四种重金属对刺参幼参进行了单一急性毒性试验。结果表明:Cu2 对刺参幼参的24h,48h,72h和96hLC50分别为0.299,0.176,0.133和0.120mg/L;Zn2 的24h,48h,72h和96hLC50分别为6.700,3.624,2.577和1.951mg/L;Cd2 的24h,48h和72hLC50分别为4.246,2.588和2.137mg/L;Cr6 的24h,48h和72hLC50分别为31.974,7.499和3.808mg/L;Cu2 ,Zn2 ,Cd2 和Cr6 对刺参幼参的安全浓度分别为0.018,0.362,0.259和0.750mg/L。四种重金属对刺参幼参的毒性大小依次为Cu2 >Cd2 >Zn2 >Cr6 。     

Tracing dissolved organic matter cycling in the eastern boundary of the temperate North Atlantic using absorption and fluorescence spectroscopy

Apparent oxygen utilization (AOU), dissolved organic carbon (DOC), coloured dissolved organic matter (CDOM) absorption spectra, and CDOM fluorescence characteristic of aromatic amino acids (excitation/emission 280 nm/320 nm; F(280/320)) and marine-humic like substances (320 nm/410 nm; F(320/410)) were measured in full depth during a cruise in the temperate Eastern North Atlantic (ENA). An optimum multi-parameter (OMP) inverse method was run to calculate water mass proportion-weighted average (archetypal) concentrations of these chemical parameters for all water masses and samples. Archetypal concentrations retain the variability due to water mass mixing and basin scale mineralization from the water mass formation sites to the study area. Conversely, the difference between measured and archetypal concentrations, retain the variability due to dissimilarities in mineralization processes within the study area. Our analysis indicates that DOC supported 26±3% of the AOU in the dark temperate ENA and that basin scale processes occurring at and from the formation area of the water masses explained 63% of the total DOC variability. Our data also suggests that DOC remineralized at the basin scale was of lower molecular weight, and with a lower proportion of fluorescent aromatic amino acids than found within the study area. The relationship between the absorption coefficient at 254 nm (a_CDOM(254)) and AOU indicates that a_CDOM(254) was consumed during organic matter remineralization in the dark ocean, with 55% of the variability being explained by basin scale processes. The relationships of F(320/410) with AOU and DOC confirmed that marine humic-like substances are produced by microbial degradation processes, at a rate of 6.1±0.9×10⁻³ mg equivalents of QS mol AOU⁻¹. Our results also indicate that basin-scale remineralization processes account for 85% of the total variability of F(320/410), emphasizing that large scale processes control the formation of humic-like substance in the dark ENA.     

海洋中β-二甲基巯基丙酸内盐降解过程的研究进展

二甲基硫(DMS)是海水中一种最重要的、含量最丰富的还原态挥发性生源有机硫化物,前体β-二甲基巯基丙酸内盐(DMSP)的降解过程受各种因素影响。其中主要包括温度、DMSP的浓度、氧气、盐度、酸度、颗粒粒度、藻类生长期、季节变化、氧化压力、抑制剂等。它们均与DMSP降解速率呈一定的函数关系,并对DMSP的降解产物产生影响。藻类是DMSP的主要来源,因此着重讨论了温度、盐度、酸度等对不同浮游植物细胞内DMSP与DMS生物生产和转化过程的影响。结合海洋硫循环的研究现状和海洋化学发展的趋势,探究了用颗粒态DMSP与Chla的比率来量化碳和硫通量的方法及DMSP裂解酶活性的检验技术。大气中CO2压力持续增加导致的海洋酸化对藻类中DMSP降解过程的影响也是进一步研究的重点。     

Ballast water management in Canada: A historical perspective and implications for the future

Non-indigenous species (NIS) can create significant risks when introduced to foreign ecosystems. One of the many vectors facilitating the global transport of NIS is ballast water, and as commercial shipping increases so does the threat of ballast water-mediated introductions. Despite Canadian regulations, consistent with international guidelines put forth by the International Maritime Organization in the early 1990s, ballast water remains a potential vector for the introduction of many NIS to Canadian marine ecosystems: there have been no new introductions in the Laurentian Great Lakes Region since 2006, yet marine ecosystems continue to see the introduction and establishment of NIS. This paper details and analyzes the development of Canadian ballast water management (BWM), in the context of marine ecosystems, and identifies issues therein. BWM in Canada has a number of management gaps that have persisted since large-scale BWM began in the late 1980s. These include BWM exemptions for vessels not exiting the North American continental shelf, and limitations of effectiveness of mid-ocean exchange as the predominant management method in marine ecosystems. In addition, ballast water regulations for the Canadian Arctic may require additional consideration as the Arctic will likely continue to see an increase in both warming and commercial shipping in the future, thereby increasing the potential risk of NIS. In order to adequately protect all Canadian marine ecosystems, it is recommended that the current BWM regime: fill gaps in management to help prevent further introduction and spread of NIS; focus equally on both marine and freshwater regions, and; look to other aggressive BWM strategies such as those being developed by the state of California.     

Sources and implications of particulate organic matter from a small tropical river—Zuari River,India

Transitional ecosystems,estuaries and the coastal seas,are distinctively affected by natural and anthropogenic factors.Organic matter(OM)originating from terrestrial sources is exported by rivers and forms a key component of the global biogeochemical cycles.Most previous studies focused on the bulk biochemical and anthropogenic aspects affecting these ecosystems.In the present study,we examined the sources and fate of OM entrained within suspended particulate matter(SPM)of the Zuari River and its estuary,west coast of India.Besides using amino acid(AA)enantiomers(L-and D-forms)as biomarkers,other bulk biochemical parameters viz.particulate organic carbon(POC),δ13C,particulate nitrogen(PN),δ15N and chlorophyll a were analyzed.Surprisingly no significant temporal variations were observed in the parameters analyzed;nonetheless,salinity,POC,δ13C,PN,δ15N,glutamic acid,serine,alanine,tyrosine,leucine and D-aspartic acid exhibited significant spatial variability suggesting source differentiation.The POC content displayed weak temporal variability with low values observed during the post-monsoon season attributed to inputs from mixed sources.Estuarine samples were less depleted than the riverine samples suggesting contributions from marine plankton in addition to contributions from river plankton and terrestrial C3 plants detritus.Labile OM was observed during the monsoon and post-monsoon seasons in the estuarine region.More degraded OM was noticed during the pre-monsoon season.Principal component analysis was used to ascertain the sources and factors influencing OM.Principally five factors were extracted explaining 84.52%of the total variance.The first component accounted for 27.10%of the variance suggesting the dominance of tidal influence whereas,the second component accounted for heterotrophic bacteria and their remnants associated with the particulate matter,contributing primarily to the AA pool.Based on this study we ascertained the role of the estuarine turbidity maximum(ETM)controlling the sources of POM and its implications to small tropical rivers.Thus,changes in temporal and regional settings are more likely to affect the natural biogeochemical cycles of small tropical rivers.     

Seabed Ground Improvement in Coastal Reclamation Area by Heavy Tamping After Rockfilling Displacement

Considering the characteristics of seabed ground in coastal reclamation area, ultra soft clay improvement method by heavy tamping after rockfilling displacement was proposed combined with a case study. The improvement mechanisms of the method can primarily be attributed to rockfilling displacement (RD), dynamic compaction (DC), dynamic replacement (DR) and dynamic replacement and mixing (DRM). For the case study given in this article, heavy tamping construction program was proposed based on field pilot tests. Furthermore, the effectiveness of the proposed ground improvement method was verified through in situ plate load test, sand fill test and the analyses of observed settlement data. Thus, the method of heavy tamping after rockfilling displacement is applicable for the improvement of seabed ground in coastal reclamation area. It is proposed for similar projects that heavy tamping of fills may be performed by layers and correspondingly tamping energy increased to further enhance the improvement effect of DC, DR and DRM. In addition, delayed improvement effect or time effect of soil mass after heavy tamping is still an issue to be further studied.     

莱州湾海域水体中有机氯农药和多氯联苯的浓度水平和分布特征

以固相萃取/气相色谱法测定了莱州湾海域水体中22种有机氯农药和多氯联苯类化合物的浓度水平和分布特征。结果表明,莱州湾海域表层水体中有机氯农药浓度范围为N.D.~32.7ng/L,底层水中的浓度范围为N.D.~11.7ng/L。在该海域水体中共检出有机氯农药3种,β-666是水体中主要的有机氯农药污染物。多氯联苯类在底层水样中检出2种,总浓度范围在4.5~27.7ng/L之间。该海域有机氯农药和多氯联苯的分布特征是近岸高,离岸低,由近岸向湾外延伸方向依次递减。并对莱州湾表层水中总有机氯农药与海水盐度、氯度、溶解氧和pH间的关系作了初步探讨,得出总有机氯农药与盐度、氯度间有一定的相关关系,相关系数均为0.59。方法测定5种有机氯农药化合物的空白加标回收率为97.3%~126.0%,相对标准偏差为2.8%~8.6%;测定5种多氯联苯类化合物的空白加标回收率为88.6%~151.8%,相对标准偏差为6.7%~10.4%。     

空间信息系统原理(三)数字高程模型及其数据结构

简要介绍了DTM的提出和应用情况,并对数字地面模型(DTM)、数字高程模型(DEM或DHM)、数字地形模型(DGM)等三个概念进行了论述,说明了它们的区别和联系,详细论述了离散点、不规则三角形、等高线、断面线和规则格网等几种数字高程模型的数据结构,并对不同数据结构的数字地面模型的特征进行了比较。     

Material selection for the gas containment system of a compressed natural gas carrier fleet

In this work, the possible exploitation of fiber-reinforced composites in the context of maritime transportation of compressed natural gas (CNG) is investigated. In addition to a more conventional steel configuration, two different fiber materials, carbon and glass, are considered as construction materials for pressure vessels (PVs) to be stored on board ships, with thickness optimized by FEM analysis.The considered scenario is represented by the transportation of CNG from an offshore well to a terminal on shore. Fleets of ships carrying CNG in pressure vessels manufactured with the investigated materials are generated by means of a ship synthesis model (SSM) software and compared on the basis of technical and economical indicators.The choice of the construction material influences considerably the weight of the PVs, which represent a major item of total ship weight and reflects directly on the general transport performances in terms of resistance, seakeeping and reliability in the service. On the other hand, capital as well as operating expenditures are considerably affected by the choice. When exploring the design space, the ship synthesis model is able, at a preliminary stage of the design, to account for the various technical and economical aspects, their implications and relationships. Results are presented of computations carried out in a specific case, identified by the annual gas production and other characteristics of the well terminal and a cruising route for the ships. The comparison is carried out on the basis of the cost per transported unit of gas and of the percentage of success in the transportation process. The computations show that the choice of the PV material has a key influence on the results in terms of optimal number, dimensions and speed of the ships.     

基于EMD和辛几何的运动员表面肌电信号分析与评价

为对肌电信号的物理解释做出探索性的工作，本文运用经验模态分解和辛几何的方法，对不同等级短跑运动员腿部不同肌群的表面肌电信号进行处理分析。试验结果初步表明，应用上述2种方法可对运动员等级和竞技状态做出有效的评价，而且2种方法对肌电信号处理结果的一致性将有助于进一步描述肌肉系统的生物力学特性。