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为了方便的存储和管理资源描述框架(RDF)数据,文中对利用Oracle空间网络数据模型存储RDF数据的方法做了改进.对改进前后得到的结果进行比较分析,并通过实验证明对基于Oracle空间网络模型存储RDF数据方法的改进不仅能够方便快捷的导入RDF,实现对RDF数据的有效管理,而且能够节省存储时间,提高了存储效率. 相似文献
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海洋水色遥感元数据及其系统设计 总被引：3，自引：0，他引：3
在参考国内外元数据标准的基础上,提出了一个海洋水色遥感元数据框架,可以用来对海洋水色遥感数据进行描述、组织、存储和管理;在此基础上,利用XML Schema对此元数据框架进行描述,从而可以用于规范海洋水色遥感元数据。其次,从元数据的访问接口、存储系统及其安全体系结构方面设计元数据系统,实现对海洋水色遥感元数据的有效存储和管理。最后,对海洋水色遥感元数据系统进行功能和性能评价。 相似文献
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介绍ITRF2014的定义、测站分布、输入数据、分析策略以及与ITRF2008的转换参数,并分析ITRF2014相对于ITRF2008的改进。ITRF2014是国际地球参考框架ITRF的最近一次更新,它是基于四种空间大地测量技术(VLBI、SLR、GNSS和DORIS)重新处理解实现的。相较于ITRF2008,ITRF2014不仅在观测数据和测站数量上有所增加,还改善了对非线性运动的处理,包括对周期性信号的估计以及对震后形变(post-seismic deformation,PSD)的改正,并提供了PSD模型和地球质心运动模型两个新产品。ITRF2014为地球科学等相关领域的研究与应用提供了统一的空间基准,也为其他坐标框架的维持与精化提供了参考。 相似文献
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国际上几种海洋元数据内容剖析 总被引：2，自引：0，他引：2
本文介绍了国际上几种海洋元数据内容和运行背景．主要有MEDI、ODAS元数据、EDIOS、EDMED和ARGO元数据。并对这些元数据的特点进行了归纳、分析和比较。提出了海洋元数据描述对象和建立目的在海洋信息元数据标准建设中的重要性。希望能对我国海洋信息化建设的元数据技术研究和开发提供参考。 相似文献
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海洋测绘信息元数据标准研究 总被引：2，自引：3，他引：2
介绍了国际标准化组织关于地理信息元数据的定义和国际国内标准化的现状，以及国际海道测量组织关于电子海图元目标的定义；分析了我国关于数字海图的元数据现状。围绕海洋测绘信息元数据涵盖范围、分级分类、描述方法等方面，探讨了建立海洋测绘信息元数据标准体系的必要性和可行的方法。 相似文献
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论述了地理空间元数据及元数据标准在地理空间数据共享中的重要作用，分析了空间元数据格式的技术要求，引入网络环境中的标准文本格式XML及其相关技术，显示应用XML进行空间元数据管理的优势。以地理信息一元数据标准为例，介绍规定数据类型及格式要求的XML Schema文件，并用于对存储元数据的XML文档进行有效性检查。设计XSL文件实现XML文档的树状嵌套输出样式。元数据编辑器通过DOM解析XML文档中的元素节点进行数据更新、添加、删除操作，实现对元数据的管理。 相似文献
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本文研究了用ＡＲＭＡ模型描述海浪运动的数学模型。通过ＡＲＭＡ模型的参数估计，给出了描述海浪运动的ＡＲＭＡ模型，利用仿真数据进行了拟合检验。结果表明：本文提出的海浪ＡＲＭＡ模型是一种非常理想的数学模型，且适于在线递推运算，便于工程应用。 相似文献
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针对大地测量成果的数据量大、类型复杂等特点，建立了基于GIS与信息管理系统（MIS）集成的系统来实现对于大地测量成果的属性管理与地图查询及浏览。提出了大地测量成果应用系统的整体建设方案，讨论了利用GIS与MIS集成技术实现大地测量成果管理的理论及技术可行性，并对于大地成果的数据库管理技术、GIS与MIS的系统集成技术以及数据输出等方面进行了详细的阐述。 相似文献
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Arne Schnack-Friedrichsen Angela M. Davis Jim D. Bennell Dei G. Huws 《Marine Georesources & Geotechnology》2001,19(4):221-243
The interdependence between the seismo-acoustic properties of a marine sediment and its geotechnical/physical parameters has been known for many years, and it has been postulated that this should allow the extraction of geotechnical information from seismic data. Though in the literature many correlations have been published for the surficial layer, there is a lack of information for greater sediment depths. In this article, a desktop study on a synthetic seafloor model illustrates how the application of published near-surface prediction equations to subsurface sediments (up to several tens of meters burial depth) can lead to spurious predictions. To test this further, acoustic and geotechnical properties were measured on a number of sediment core samples, some of which were subjected to loading in acoustically-equipped consolidation cells (oedometers) to simulate greater burial depth conditions. For low effective pressures (representing small burial depths extending to around 10 meters subsurface), the general applicability of established relationships was confirmed: the prediction of porosity, bulk density, and mean grain size from acoustic velocity and impedance appears generally possible for the investigated sedimentary environments. As effective pressure increases through, the observed relationships deviate more and more from the established ones for the near-surface area. For the samples tested in this study, in some instances increasing pressure even resulted in decreasing velocities. There are several possible explanations for this abnormal behavior, including the presence of gas, overconsolidation, or bimodal grain size distribution. The results indicate that an appropriate depth correction must be introduced into the published prediction equations in order to obtain reliable estimates of physical sediment properties for greater subsurface depths. 相似文献
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Shigehisa Nakamura 《Marine Geodesy》2000,23(1):55-61
Specific properties of the interannual sea level variations and annual tides in the Northwestern Pacific were studied. Several tide stations were monitored. The monthly mean sea level for the year of 1995 was analyzed at each tide station. A seismic event in 1995, some tectonic activity around the subject area, and the Kuroshio (the oceanic western boundary current) may possibly contaminate results which would have occurred from the astronomical annual tide alone. 相似文献
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The effect of different fixation and storage protocols on the flow cytometric (FCM) simultaneous analysis of bacterioplankton and phytoplankton in coastal seawater samples (Mediterranean coastal lagoons) was investigated. FCM measurements (cell number, fluorescence and scatter characteristics) were obtained through DAPI staining. Three fixatives [glutaraldehyde (GA), formaldehyde (FA) and paraformaldehyde (PFA)] and two storage (3 months duration) methods (5 °C and −196 °C) were tested. Two dominant populations were detected in studied samples: bacteria and eukaryotic picophytoplankton. Adding fixatives (2% final concentration) appears necessary to obtain FCM exhaustive counts of all the bacteria and phytoplanktonic cells. This was related to the permeation effect of fixatives which allowed a better DAPI staining of the cells. Maximum fluorescence, i.e. optimal staining of the cells was obtained with FA or PFA, and significant lower fluorescences with GA. Fixed samples stored at 5 °C induced rapid cell loss. Only storage in liquid nitrogen of samples fixed with FA or PFA, allows mid-term (≥4 months) preservation of bacteria or picophytoplankton cell numbers, and limited evolution of DAPI-induced fluorescence and scatter characteristics. 相似文献
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Coastal inundation associated with extreme sea levels is the main factor which leads to the loss of life and property whenever a severe tropical cyclonic storm hits the Indian coasts. The Andhra and Orissa coasts are most vulnerable for coastal inundation due to extreme rise in sea levels associated with tropical cyclones. Loss of life may be minimized if extreme sea levels and associated coastal flooding is predicted well in advance. Keeping this in view, location specific coastal inundation models are developed and applied for the Andhra and Orissa coasts of India. Several numerical experiments are carried out using the data of past severe cyclones that struck these regions. The simulated inland inundation distances are found to be in general agreement with the reported flooding. 相似文献
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《海洋学报(英文版)》2014,(9):F0003-F0003
<正>Acta Oceanologica Sinica(AOS)is a comprehensive academic journal edited by the Editorial Committee of Acta Oceanologica Sinica and is designed to provide a forum for important research papers of the marine scientific community which reflect the information on a worldwide basis.The journal publishes scholarly papers on marine science and technology,including physics,chemistry,biology, 相似文献
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Hoi-Soo Jung Kap-Sik Jeong Yong-Shik Chu Sung-Hyun Park Ki-Hyune Kim 《Marine Georesources & Geotechnology》2001,19(3):181-195
Grain size and water content in box-core sediments from the Clarion-Clipperton fracture zone (C-C zone) in the northeast equatorial Pacific were analyzed in detail to understand the downcore variations across a hiatus between Quaternary and Tertiary layers. Grain-size distributions in the topmost core sediments show two modes: a coarse mode (peaked at 50 μm) and a fine mode (at 2-25 μm). The coarse mode disappears gradually with depth accompanied by the dissolution of siliceous fossil tests, whereas the fine mode coarsens due to the formation of authigenic minerals. Water content increases abruptly across a color boundary between an upper pale brown layer and a lower dark brown layer that is the hiatus between Quaternary and Tertiary layers. Abundant smectites and microvoid molds, which are created by the prolonged fossil dissolution in the underlying sediment, are attributed for the abrupt downcore variation of water content. Overall variations in grain size and water content in the topmost core sediments in the western C-C zone are possibly constrained by the dissolution of biogenic siliceous fossils. Variations in geotechnical properties related to these changes must be considered in the design of nodule collectors. 相似文献
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Shigehisa Nakamura 《Marine Geodesy》2001,24(1):27-33
This article concerns an interrelation between the sea levels and the western boundary flow near a tectonic boundary in a local zone in the Northwestern Pacific. In this zone, sea level variations at stations located on the coast facing the Pacific are studied to find the interrelation between variations of the Kurosio flow as an index of the distance of the flow axis off a specific coast. The result is discussed after data processing of the monthly means of the sea levels, and a notice is taken of variations caused by active crustal upheavals during a seismic event, a local earthquake. 相似文献
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This study tests the hypothesis that the in situ void ratio of surficial marine sediments may be predicted from shear wave velocity-depth data with a reliability equal to that of other methods currently available. Shear wave velocity is fundamentally controlled by the number of grain-to-grain contacts per unit volume of material and by the effective stress across those contacts. In this study, three previously established empirical formulae are used to predict void ratio from velocity-depth data. Field data were acquired along a transect off the northern Californian coast across which water depth increased from 35 to 70 m and seafloor sediment type varied from sand to silty-sand, respectively. A towed seafloor sled device was used to collect shear wave refraction data, and a marked, systematic decrease in velocity was observed along the line, ranging from 35-70 m/s for the coarse, near-shore material to 25-40 m/s for the finer, offshore deposits. Void ratios predicted from these velocities were compared with data measured directly from box-core samples. Of the formulae used for prediction, two agree remarkably well with the control data. Both predicted and control values increase from 0.6-0.8 for the sandy material to 1.1-1.5 for the silty-sand. Thus, this study does not disprove the hypothesis set and demonstrates the potential of field shear wave velocity-depth data as a means of delineating spatial variation in void ratio for surficial marine sediments in a remote, nondestructive manner. 相似文献
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Particulate samples were collected from the Changjiang river system during a flood period, in May 1997, and POC, stable isotope and lipids associated with particles were examined. Results showed the decrease (0.84% ～ 1.88%) of organic carbon content from the upper reaches to the estuary.δ13C values of particulate organic carbon was in the range of -24.9×10-3 to -26.6×10-3, which were close to the isotopic signature of continental C3 vegetation. Total particulate n-alkanes concentrations varied from 1.4 to 10.1μg/dm3,or from 23.7 to 107μg/g of total suspended matter. Fatty acids were present in all the samples, from 1.4 to 5.4μg/dm3, with saturated and unsaturated straight-chain and branched compounds in the carbon number range from C12 to C30. Both δ13C and the ratio of carbon content to nitrogen content indicate the predominance of terrestrial inputs (soil organic matter) among the particles. The biomarker approach has been used to identify the relative portion of terrigenous and autochthonous fraction in the particulate samples. The distribution of fatty acids suggests a striking phytoplanktonic and microbial signal in most particle samples. The terrestrial alkanes are used to estimate the contribution of terrestrial inputs along the mainstream. 相似文献