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111.
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由于研究主题和应用目的的不同,国内外已经存在和正在产生着越来越多的遥感数据源的土地覆盖分类体系。这不仅使得分类体系缺乏可扩展性与互操作性,而且使得不同分类体系的土地覆盖数据难以对比、交换和集成。本文借鉴ISO 19115地理信息元数据的扩展经验,设计了基于ISO元数据扩展模型的土地覆盖分类体系框架,并研究其动态扩展方法。提出一种包括核心分类、全集分类和专题应用分类的三层土地覆盖可扩展分类体系框架。其中,核心分类是从国内外主要的土地利用/覆盖分类系统中抽取的共性分类元素;全集分类收集全部可能的土地覆盖分类元素;专题应用分类通过对核心分类的继承,和对全集分类的裁剪和扩展生成。该分类框架将为土地利用/覆盖的研究和应用提供一种科学的、可比的动态分类扩展模型和方法。 相似文献
113.
Wave run-up on foundations is a very important factor in the design of entrance platforms for offshore wind turbines. When the Horns Reef 1 wind turbine park in Denmark was designed the vertical wave run-up phenomenon was not well known in the industry, hence not sufficiently considered in the design of Horns Reef 1. As a consequence damage was observed on the platforms. This has been the situation for several sites and design tools for platform loads are lacking. As a consequence a physical model test study was initiated at Aalborg University to clarify wave run-up on cylindrical piles for different values of diameter to water depth ratios (D/h) and different wave heights to water depth ratios (H/h) for both regular and irregular waves. A calculation model is calibrated based on stream function theory for crest kinematics and velocity head stagnation theory. Due to increased velocities close to the pile an empirical factor is included on the velocity head. The evaluation of the calculation model shows that an accurate design rule can be established even in breaking wave conditions. However, calibration of a load model showed that it was necessary to increase the run-up factor on the velocity head by 40% to take into account the underestimation of run-up for breaking or nearly breaking waves given that they produce thin run-up wedges and air entrainment, two factors not coped with by the measurement system. 相似文献
114.
ISO9000系列标准是国际公认的质量管理和质量保证统一标准,具有科学性、有效性、通用性的特点。贯彻ISO9000系列标准,是深化和发展单位管理规范、建立和完善质量体系的需要。通过贯标取得认证,可以提高测绘单位的知名度,取得用户的信任,在市场竞争中立于不败之地。 相似文献
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用南海西沙站观测资料诊断研究南海季风季节内振荡 总被引:1,自引:0,他引:1
应用Lanczos滤波和小波变换方法,对1958~2000年南海北部西沙站降水和1980~2001年850hPa风场观测资料进行分析,发现西沙站每日降水和850hPa风场都存在谱长度10~50d左右其峰值为10~20,30~50d的季节内振荡,降水和850hPa风场的季节内振荡都有明显的年变化.降水季节内振荡开始于5月中旬结束于10月中旬,与南海夏季风的爆发时间和终止时间一致.850hPa风场谱长度10~50d左右其峰值为10~20,30~50d的季节内振荡在一年中的大部分时间都存在.降水和850hPa风场季节内振荡的强弱年与南海夏季风的强弱年并不一致.研究表明南海夏季风存在季节内振荡,而南海夏季风与季节内振荡的关系比较复杂. 相似文献
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ISO19100地理信息系列标准特点及其本土化 总被引:9,自引:3,他引:6
采用国际标准和国外先进标准是国民经济发展的重要技术基础工作。文章简略介绍国际标准化组织地理信息技术委员会(ISO/TC211)研制ISO19100地理信息系列标准的概况,着重分析其结构体系、研制特点,讨论将这些标准转化为国家标准,即本土化工作应当遵循的原则、方法、国家标准与国际标准一致性程度划分等问题,并提出ISO19100地理信息系列标准本土化工作的建议。 相似文献
118.
《Marine Policy》2015
A recent article by Sierra-Correa and Cantera Kintz published in Marine Policy 51 2015 identifies the need for systematic reviews of evidence to inform marine policy and management. To guide their review, the authors apply the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) Statement as a methodology. We identified eighteen systematic reviews published on marine topics between 2008 and 2015. Of those which stated a methodology (N=12), 25% (N=3) applied the PRISMA Statement. PRISMA is a checklist designed by the medical community to improve reporting standards of systematic reviews and meta-analyses, rather than guidelines for their conduct. Relevant guidelines have already been produced by the Collaboration for Environmental Evidence. By using PRISMA as a methodology without referring to these guidelines, or worse, post hoc without conducting a full systematic review, authors may unintentionally give the impression of having undertaken a more rigorous review than is in fact the case. Given the apparent increase in systematic reviews of marine and coastal topics, it is vital that appropriate methodology be used. Authors undertaking future reviews should use existing environmental systematic review guidance to help plan and conduct their review. By following these guidelines, standards for marine reviews should increase, ultimately resulting in more rigorous reviews better able to inform future marine science and policy. 相似文献
119.
Surface sediments from the Saronikos Gulf were analyzed for their aliphatic hydrocarbon (AHC) and polycyclic aromatic hydrocarbon (PAH) content by gas chromatography – mass spectrometry (GC/MS). The concentrations of Fe, Cr, As, Sb, Co and Sc were also determined by neutron activation analysis (NAA). The survey was performed at the beginning of the operation of Athens’ sewage primary treatment unit and the results can be used to monitor the unit's long-term effects in the area. The composition of aliphatic hydrocarbons indicated a chronic oil-pollution in the Saronikos Gulf sediments. The industrially impacted Elefsis Bay sediments suffered from heavy petroleum pollution, while the sediments near the sewage outfall had a moderate degree of pollution. Mixed source patterns of polycyclic aromatic hydrocarbons with dominant pyrolytic inputs have been identified in the sediments. Total concentrations of Fe, As and Sb along with their Sc normalized values presented elevated values in Elefsis Bay sediments. Chromium was found enriched in the sediments near the Athens sewage outfall. Factor analysis results showed that a part of As and Sb in Elefsis Bay sediments could be associated with organic or sulphidic phases. In addition, the lithogenic fraction of the sediments and the Fe oxides/hydroxides were important trace element carriers. Chromium and PAH inputs from the sewage outfall were also detected. Comparison of PAH and trace element concentrations with internationally-used sediment quality guidelines (SQG) revealed that Elefsis Bay sediments had the greatest potential of causing adverse effects in benthic organisms. 相似文献
120.
PA Franklin 《新西兰海洋与淡水研究杂志》2013,47(1):112-126
Maintenance of suitable conditions in lowland rivers for both fish passage and resident species is crucial to ensuring the long-term sustainability of fish populations. The dissolved oxygen concentration of water is a key factor controlling habitat quality for fish and a critical measure of stream health. Continued land use intensification and greater exploitation of water resources has contributed towards increasing the frequency and duration of low dissolved oxygen events in lowland rivers and the associated risk of adverse effects on fish communities. Revised guidelines are therefore proposed to support setting of biologically relevant dissolved oxygen limits for the protection of New Zealand freshwater fish communities. These guidelines account for both event magnitude and duration, identify different protection levels based on the risk of negative impacts and are based on current scientific knowledge on the tolerances of New Zealand fish species. 相似文献