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991.
《International Journal of Digital Earth》2013,6(1):68-87
China is one of the most disaster-prone countries in the world. Currently, the disaster prevention and relief mechanism in China is mainly based on single disaster types and is implemented by different ministries and divisions in single administrative regions. Subsequently, the available resources, including data, services, materials, and human resources, cannot be shared and used effectively. Based on the idea of an observation system of systems and a business system of systems, this paper presents an integrated framework for a Chinese National Disaster Reduction System of Systems (CNDRSS) to address this issue. The CNDRSS framework aims to achieve data sharing and collaboration among different disaster-related ministries/institutions by providing one-stop services for all phases of disaster management and linking together existing and planned disaster-related business systems and observation systems. The key technologies use federated databases and a web service to integrate multiple disaster management systems among different ministries/institutions and a sensor web to integrate airborne, space-borne, and in-situ observations through the web service. These event-driven focused-services connecting the various observations, processing, and mapping processes can meet the requirements for complex disaster-chain systems. 相似文献
992.
993.
为了减少对GPS提供的高精度授时服务的依赖,建设拥有自主知识产权的且具有投入成本低、精度高的授时系统。提出了一种利用地面高稳定度原子钟作为时频基准,通过通信卫星转发实现卫星广播授时的新方法。详细研究了利用地面高稳定度原子钟和通信卫星组成的导航星座进行多星授时、单星授时的原理和测量方法,分析研究了影响授时精度的原因。由于转发式卫星授时系统的时频基准源稳定度高,其测距精度也会相应的提高。只要精确扣除时延误差,同样可以实现高精度授时。粗码的授时精度可达20ns以内,短精码的授时精度可达10ns左右。总之该系统具有组建灵活简便、应用面广等优势和特色。 相似文献
994.
AbstractIntegrating local and Indigenous knowledge into land-use planning and the assessment of ecosystems services requires reliable, quantitative data. We tested two approaches to obtain such data by quantifying farmer opinion of different land-covers in Eastern Panama using (1) the analytic hierarchy process (AHP) and (2) a simpler ranking and scoring technique. Both methods produce a set of numerical values reflecting the ability of land-covers to deliver ecological and socio-economic criteria. We present our experience with both methods and offer recommendations for researchers looking to quantify landholder opinion. The AHP survey was relatively long (on average it took 19?min to complete per criterion) and we faced problems with inconsistent responses. In contrast, the ranking and scoring method was much quicker (only 3?min per criterion) and therefore may be more suitable for gathering more data from a larger number of farmers. 相似文献
995.
Julia Jones Auro Almeida Felipe Cisneros Andres Iroumé Esteban Jobbágy Antonio Lara Walter de Paula Lima Christian Little Carlos Llerena Luis Silveira Juan Camilo Villegas 《水文研究》2017,31(5):972-980
South America is experiencing rapid change in forest cover, of both native and planted forest. Forest cover loss is primarily attributable to fire, logging, and conversion of native forest to agriculture, pasture, and forest plantations, and types of change vary within and among the many diverse types of forests in South America. Major changes in forest cover and growing policy concerns underscore an urgent need for research on sustainable forest management and water ecosystem services in South America. Differences in land ownership and management objectives create trade‐offs between wood production and water ecosystem services from forests. Work is needed to quantify how forest change and management affect ecosystem services, such as wood production versus water provision. Current scientific understanding of forest management effects on water ecosystem services in South America has important limitations, including a scarcity of long‐term records and few long‐term integrated watershed studies. Industry, government, universities, and local communities should collaborate on integrated applied studies of forests and water. Data archiving and publically available data are required. The creation of national networks and a multi‐country South America network to identify and implement common water research protocols, share results, and explore their implications would promote common and well‐supported policies. Hydrologists working in South America are well placed to tackle the challenges and opportunities for collaborative research that will maintain the intrinsic values and water ecosystem services provided by South America's forests. 相似文献
996.
Forest ecosystem services and their values in Beijing 总被引:5,自引:3,他引:2
Gaodi Xie Wenhua Li Yu Xiao Biao Zhang Chunxia Lu Kai An Jixing Wang Kang Xu Jinzeng Wang 《中国地理科学(英文版)》2010,20(1):51-58
As the most important ecosystem in Beijing, the forest supports a lot of ecosystem services to local and around communities, which plays a key role in the maintenance of urban ecological security.However, the valuation on the forest ecosystem services based on regional scale could not provide precise and reasonable values for forestry sector management.In this study, we estimated the magnitudes and economic values of the forest ecosystem services in Beijing at sublot level.The economic value of forest ecosystem services in Beijing was estimated to be 19 339.71×10 6 yuan(RMB) in 2004.Among all the ecosystem services indicators we estimated in this study, only fruit, timber and part of the recreation(which only include the tourism income from the forest parks and scenic areas, but not include that from other forest types) were measured in the social economic system.As estimated in this study, more than 82.19% of the economic value of forest ecosystem services could not be measured in the socio-economic statistical system.The importance of forest ecosystem services in Beijing to human welfare was underestimated by the socio-economic system.Therefore, the policies about the eco-compensation of forest ecosystem services should be established to maintain the sustainable supply of the forest ecosystem services in Beijing. 相似文献
997.
空间数据访问集成与分布式空间数据源对象查询 总被引:1,自引:0,他引:1
目前,针对空间数据库的访问与处理方法,无法满足分布式环境下异构数据源的服务化存取和面向空间数据源的对象查询处理需求。本文给出了数据网格环境下的分布式空间数据访问与查询的方法和实现,并在服务化查询处理过程中,嵌入符合SQL/MM查询规范的空间拓展函数,实现分布式空间数据对象查询和嵌入查询过程中的空间数据分析处理。在此基础上,给出空间数据对象查询树的构造过程,以及分布式空间查询工作流的执行流程。数据访问与集成策略在空间数据处理上的应用,对异构空间数据源协同处理等,涉及大规模空间数据存取访问的应用需求,有很好的理论和实际应用价值。 相似文献
998.
���ģ��վ���������������̽�� 总被引:1,自引:0,他引:1
?????????????????CORS???????????????????????????????????????????CORS?????????????????CORS?????????????????FCM???????????????????????????????????????????????????????????????????????????????÷????????y????????????????????????????????????????????? 相似文献
999.
1000.
基于生态服务价值的伊犁河谷土地利用变化环境影响评价 总被引:10,自引:3,他引:7
运用遥感技术、GIS和实地调查方法,对新疆伊犁河谷1985—2005年间的土地利用变化进行了分析,同时借助土地利用变化驱动下的生态服务价值变化量,探讨了研究区土地利用变化对生态环境的影响及效应。结果表明,1985—2005年,研究区耕地、水域和建设用地面积增加,林地、草地和未利用地面积减少,其中耕地和草地面积变化最大,分别为31.53万 hm2和-29.02万hm2。土地利用变化引起了研究区生态环境的变化,对生态服务价值亦产生了一定的影响,伊犁河谷生态服务功能整体提高了4.43%,其中正向变化最大的特克斯县,其生态服务功能增加了7.57%,负向变化最大的是伊宁市,其生态服务功能下降了27.33%;各单项服务功能价值中,生态系统所提供的气体调节、土壤形成与保护、生物多样性保护和原材料等4项生态服务功能有所下降,其余8项生态服务功能均有不同程度的提高。敏感度分析表明,赋予生态服务功能价值指数的大小对研究区总的生态服务价值变化影响不明显,研究结果可信。 相似文献