简易船舶GPS、艏向显示器的设计

针对目前许多小型渔货船上没有罗经导航仪的现状,设计了一套成本较低的船舶GPS艏向显示器。简易船舶GPS、艏向显示器由主控制器、电子罗经传感器、GPS模块、TFT液晶显示屏、电源稳压模块组成。通过主控制器处理电子罗经传感器测得的船艏向信息、GPS模块测得的地理位置信息,再驱动液晶显示屏显示实时时间、经纬度、船速、船艏向角等航行信息,提高航行安全性。经实验测试,简易船舶GPS艏向显示器性能稳定,设备小巧,价格低廉,适合在小型渔货船上推广应用。     

渔船远航中磁罗经自差自行校正的探讨

在党的改革开放方针政策的指引下，我国的远洋渔业生产发展迅速。近几年来已有几百艘渔船离开传统的近海渔场，分赴世界各地从事生产。有些船已驶往高纬度地区，如美国的阿拉斯加；有的则越过赤道南下，抵达西非、南美等地。目前，渔船上指示航向的仪器有磁罗经和电罗经两种，但在90％以上的船上仍使用磁罗经。即便使用电罗经的船舶，为安全保障计，船上仍必须装备磁罗经。     

渔船远航中磁罗经自差自行校正的探讨

在党的改革开放方针政策的指引下，我国的远洋渔业生产发展迅速。近几年来已有几百艘渔船离开传统的近海渔场，分赴世界各地从事生产。有些船已驶往高纬度地区，如美国的阿拉斯加；有的则越过赤道南下，抵达西非、南美等地。目前，渔船上指示航向的仪器有磁罗经和电罗经两种，但在90％以上的船上仍使用磁罗经。即便使用电罗经的船舶，为安全保障计，船上仍必须装备磁罗经。     

基于Cocoon框架的网页自适应转换模型研究

针对大多数WEB资源不能被无线访问或访问效果差的问题,提出了一种基于Cocoon框架的网页自适应转换模型,通过加入设备自适应性转换器,实现了使用支持XHTMLMP格式的移动终端设备访问互联网资源功能。模型中的核心管道添加了一个自适应转换器,该转换器通过构建对象模型、分割对象及重组资源,解决了小屏幕设备上显示Web网页下拉操作过长、布局不合理、表格嵌套混乱等问题,保持了良好的语义完整性和适用性．     

基于Cocoon框架的网页自适应转换模型研究

针对大多数WEB资源不能被无线访问或访问效果差的问题, 提出了一种基于Cocoon框架的网页自适应转换模型, 通过加入设备自适应性转换器, 实现了使用支持XHTML MP格式的移动终端设备访问互联网资源功能. 模型中的核心管道添加了一个自适应转换器, 该转换器通过构建对象模型、分割对象及重组资源, 解决了小屏幕设备上显示Web网页下拉操作过长、布局不合理、表格嵌套混乱等问题, 保持了良好的语义完整性和适用性.     

浅谈电子档案在管理中存在的问题及对策探讨

<正>做好电子档案的管理工作,成为当前档案管理工作的重要内容。电子档案指在数字设备及环境中生成,以数码形式存储于磁带、磁盘、光盘、优盘等载体,依赖计算机等数字设备阅读、处理,并可在通信网络上传送的档案文件。但电子档案在工作实践中还存在以下问题需要我们加以注意和解决。1.电子档案在工作实践中存在的问题。1.1电子档案极易发生失真问题。电子档案在操作过程中稍有疏忽就会导致信息失真,而且这种失真性会伴随电     

磁通门罗盘的研究

作者通过对磁通门的原理和特点的分析,探讨了它作为方向指向系统代替航海中传统的磁罗经的必要性和可行性,同时对磁通门罗盘的研制方法作了介绍,并给出了测试结果。最后还对进一步研制海上使用的磁通门罗盘尚需解决的问题进行了分析。     

海参捕捞装置导航中低成本陀螺仪的降噪研究与试验

针对MEMS陀螺仪输出信号中含有的随机漂移噪声造成海参捕捞装置惯性导航精度明显下降的问题,采用时间序列分析法和Kalman滤波算法,对MEMS陀螺仪随机漂移噪声的削减问题进行研究。以MEMS惯性测量单元的实测数据和三维电子罗盘测量的姿态角为样本,对本研究的低成本陀螺仪的降噪效果进行测试,试验结果表明:1)经过降噪处理后的陀螺仪随机漂移信号的方差比陀螺仪原始采样信号的方差降低1个数量级,显著改善了陀螺仪随机漂移数据的精密度;2)以高精度三维电子罗盘实测的姿态角作为参考基准,将降噪后的陀螺仪随机漂移数据导入捷联惯导姿态更新算法程序,在300s时间内,解算出的俯仰角、横滚角和航向角的均方根误差RMSE全部小于1°;与降噪前相比,相应的俯仰角、横滚角、航向角的RMSE分别降低了170.5、97.6和42.5倍,明显提高了惯性导航精度。     

GPS与船用计程仪及陀螺罗经的关系

ＧＰＳ的使用极大地方便了船舶驾驶,推动了航海仪器的发展。但它提供的某些信息是有局限性的,作者从ＧＰＳ、船用计程仪和船用陀螺罗经的原理,实验观测及航海驾驶的习惯来分析它们在航海中的使用,并讨论ＧＰＳ与船用计程仪及陀螺罗经之间的相互关系。     

厦门港海上交通信息公共服务平台的设计

为了船舶进出厦门港的安全航行，本平台通过分析厦门港通航环境，采用了卫星遥感影像图技术、IBMR全景图（虚拟三维）的航行背景图显示与AIS信息的综合显示等新技术，在互联网上发布厦门港最新助航设施、航道锚地、码头泊位、水深、全景图、水文气象、海事信息服务和AIS信息等各类船舶助航信息．该项目能够帮助船舶用户获取厦门港的海上交通信息，为进出厦门港的船舶安全航行服务，从而减少海事事故的发生．     

基于LabVIEW的电流互感器校验系统的设计与实现

以LabVIEW作为开发工具研制出了一个电流互感器的校验系统,能对在线运行的电流互感器在不停电的情况下进行监测.可通过数据分析处理软件进行比差、角差的计算,使之适用于模拟和数字信号的校验.     

几种测量方法在森林资源调查中的应用与精度分析

通过外业调查数据分析和理论推导,对林业调查中的几种测量方法进行了比较分析。研究表明：①罗盘仪由于制作粗糙,在标准样地测设中尚能满足规范要求,但随着距离和竖直角的增加,精度急剧下降,在大范围的林地面积和科研特殊需要的测量中操作不便捷,精度差,效率低;②全站仪测设样地边长不超过100 m时,半测回的距离测量可达到1/10 000,高差测量误差不超过1 cm,且受距离和竖直角的影响较小;③当面积大于3.34 hm^2,边长超过100 m时,手持全球定位系统（GPS）完全可代替罗盘仪,并可通过坐标差分或修正坐标转换参数来提高测量精度。另外,网络RTK的发展必将连同全站仪成为精准林业测量的主要仪器设备。     

Lodestone Compass: Chinese or Olmec Primacy?: Multidisciplinary analysis of an Olmec hematite artifact from San Lorenzo, Veracruz, Mexico

Considering the unique morphology (purposefully shaped polished bar with a groove) and composition (magnetic mineral with magnetic moment vector in the floating plane) of M-160, and acknowledging that the Olmec were a sophisticated people who possessed advanced knowledge and skill in working iron ore minerals, I would suggest for consideration that the Early Formative artifact M-160 was probably manufactured and used as what I have called a zeroth-order compass, if not a first-order compass. The data I have presented in this article support this hypothesis, although they are not sufficient to prove it. That M-160 could be used today as a geomagnetically directed pointer is undeniable. The original whole bar may indeed have pointed close to magnetic north-south. The groove functions well as a sighting mark, and the slight angle it makes with the axis of the bar appears to be the result of calibration rather than accident. A negative supporting argument is that M-160 looks utilitarian rather than decorative, and no function for the object other than that of a compass pointer has been suggested by anyone who has examined it critically. Whether such a pointer would have been used to point to something astronomical (zeroth-order compass) or to geomagnetic north-south (first-order compass) is entirely open to speculation. The observation of the family of Olmec site alignments 8 degrees west of north is a curiosity in its own right, and the possibility that these alignments have an astronomical or geomagnetic origin should be explored. I also believe that it is constructive to compare the first millennium Chinese, who used the lodestone compass for geomancy, with the Gulf Coast Olmec since both were agrarian-terrestrial societies. The Olmec's apparent concern with orientation and skillful use of magnetic minerals also stimulates one to draw cross-cultural parallels. The evidence and analysis offered in this article provide a basis for hypotheses of parallel cultural developments in China and the Olmec New World. If the Olmec did discover the geomagnetic orienting properties of lodestone, as did the Han Chinese, it is most reasonable to speculate that they would have used their compass for comparable geomantic purposes. It should, however, be recognized that the Olmec claim, if documented, predates the Chinese discovery of the geomagnetic lodestone compass by more than a millennium. At present, M-160 is a unique artifact and San Lorenzo a unique site: "The first civilized center of Mesoamerica and probably of the New World" (19, p. 89). Further documentation of the Olmec claim must await the discovery of similar artifacts in museums, private collections, or as yet undiscovered Olmec sites. I would welcome communications from anyone possessing information relating to such artifacts. Regardless of shape, purposefully grooved and highly polished specimens of magnetic minerals are of particular interest. It would also be useful for the archeologist excavating Olmec burials and offerings to carefully note their alignments and consider them in a geomantic context. In addition to the discovery of supporting artifacts, establishment of Olmec primacy of the lodestone compass depends on the acquisition of the archeomagnetic data for the Early Formative period. I appeal to archeologists who find good archeomagnetic samples (burned hearths and post-holes) from the Formative periods to convey this information to R. DuBois of the University of Oklahoma. In a few years, the archeomagnetic data should be available for the last three millennia and the possibilities are very exciting.     

Magnetic compass of European robins

The magnetic compass of European robins does not use the polarity of the magnetic field for detecting the north direction. The birds derive their north direction from interpreting the inclination of the axial direction of the magnetic field lines in space, and they take the direction on the magnetic north-south axis for "north" where field lines and gravity vector form the smaller angle.     

电子角规测定森林蓄积量及生长量的基础理论与实践

针对常规角规测树较为粗放的现状,该文提出了电子角规测定森林蓄积量及生长量的基本原理与方法.电子角规是电子经纬仪与PDA的有机结合,电子经纬仪测角精确,配合相应的PDA应用程序,可以准确地实现角规的量测胸高断面积功能.电子角规可以实时准确地量测树木材积,从而可以计算各树形高值以计算林分蓄积量;此外,电子角规还可以准确地测量各棵树相对于样点的坡度以进行坡度改正.为了测量蓄积生长量,该文作者在样点设置固定标桩进行两期观测.为了合理地解释森林蓄积生长,该文采用潜在计数值法,它可以合理地计算出进界木在前期的潜在量,林分实际生长量等于保留木、潜在木和进界木生长量之和.     

地方院校数字图书馆的前沿阵地——电子阅览室

不同图书馆的数字图书馆建设存在着数字鸿沟,地方院校数字图书馆建设要立足于自身情况,从电子阅览室这个数字图书馆的前沿阵地做起,进而建立面向网络的真正的数字图书馆。     

Migration along orthodromic sun compass routes by arctic birds

Flight directions of birds migrating at high geographic and magnetic latitudes can be used to test bird orientation by celestial or geomagnetic compass systems under polar conditions. Migration patterns of arctic shorebirds, revealed by tracking radar studies during an icebreaker expedition along the Northwest Passage in 1999, support predicted sun compass trajectories but cannot be reconciled with orientation along either geographic or magnetic loxodromes (rhumb lines). Sun compass routes are similar to orthodromes (great circle routes) at high latitudes, showing changing geographic courses as the birds traverse longitudes and their internal clock gets out of phase with local time. These routes bring the shorebirds from high arctic Canada to the east coast of North America, from which they make transoceanic flights to South America. The observations are also consistent with a migration link between Siberia and the Beaufort Sea region by way of sun compass routes across the Arctic Ocean.     

磁弛豫生物传感器在食品安全快速检测中的应用研究进展

快速检测作为一种高效方便的检测方式被认为是有效提高食品安全检测和临床诊断能力的重要手段.磁弛豫(magnetic relaxation switching,MRS)生物传感器因其优良的分析性能、简便的分析流程,已经成为快速检测的新方法、新工具.本研究介绍了基于不同传感原理的磁弛豫生物传感器,综述了近年来国内外磁弛豫生物...