一种北江流域年降雨量的权马尔可夫链预测模型   总被引：5，自引：1，他引：5  

刘德地  陈晓宏 《水文》2006,26(6):23-26,96

根据北江流域的48个站点的年降雨量资料和泰森多边形计算方法,计算出北江流域的面降雨量。再结合丰、偏丰、平、偏枯、枯水年的频率标准,建立了适用于北江流域年降雨量的分级数值区间,同时,验证了该序列满足马尔可夫链的要求,并考虑该年降雨量序列是相依随机变量的特点,以规范化的各阶自相关系数为权,建立了北江流域年降雨量的权马尔可夫链预测模型,实例验证结果令人满意。  相似文献   

桩-桶基础抗拔承载力分析     

刘文白  王梦瑜  周健 《上海国土资源》2006,(3):24-28,39

根据新型基础一桩-桶基础在上拔荷载作用下的颗粒流模拟试验结果,分析了桩桶基础在上拔荷载作用下土体的破坏过程,并对颗粒流模拟试验的颗粒的破坏面进行拟合,提出桩桶基础的上拔承载力计算模式。桩-桶基础的极限上拔承载力由破坏土体侧表面抗剪强度在竖直方向投影的集合及其包围土体土重和桩-桶基础自重组成,建立了桩-桶基础的上拔承载力计算公式,分析了上拔承载力影响因素。  相似文献   

新疆博格达山链新生代再生造山机理--岩石圈内切层"开""合"造山带的典型代表   总被引：11，自引：0，他引：11  

王宗秀  李涛 《地质通报》2004,23(3):286-293

博格达山链是新生代成长起来的山脉，经历了古生代初始造山、中生代伸展调整、新生代复活造山的完整发展演化历程，是开展陆内造山和再生造山研究的理想之地。针对博格达山链新生代再生造山过程中无明显变质作用、岩浆活动、韧性变形等这种“强造山”“弱表现”的造山地质记录特征，根据山体新生代的变形特点、变形构造组合，并结合深部探测资料，提出“双向挤出”断块隆升的造山模式，认为深部南北向相向运移及岩石圈的深部约束是博格达山链新生代再生造山的主要动力机制。  相似文献   

Experimental Assessment of Gradual Deformation Method     

Ning Liu  Dean S. Oliver 《Mathematical Geology》2004,36(1):65-77

Uncertainty in future reservoir performance is usually evaluated from the simulated performance of a small number of reservoir realizations. Unfortunately, most of the practical methods for generating realizations conditional to production data are only approximately correct. It is not known whether or not the recently developed method of Gradual Deformation is an approximate method or if it actually generates realizations that are distributed correctly. In this paper, we evaluate the ability of the Gradual Deformation method to correctly assess the uncertainty in reservoir predictions by comparing the distribution of conditional realizations for a small test problem with the standard distribution from a Markov Chain Monte Carlo (MCMC) method, which is known to be correct, and with distributions from several approximate methods. Although the Gradual Deformation algorithm samples inefficiently for this test problem and is clearly not an exact method, it gives similar uncertainty estimates to those obtained by MCMC method based on a relatively small number of realizations.  相似文献   

高空电报资料压缩库系统     

申学勤  谢成开 《气象》1994,20(10):46-49

历史天图高空逐日资料量大，层多，存取极不方便。该文介绍一种高效压缩的高空资料库系统，将高空资料和相应的存取软件结合在一起，形成一个微机高空资料处理系统，降低了８０％以上存储资料所需的介质空间，且方便了资料的查阅，提取，添加，插补等。  相似文献   

On the control of an infinite capacity storage system     

F. A. Attia  P. J. Brockwell 《Stochastic Environmental Research and Risk Assessment (SERRA)》1993,7(3):195-204

We consider an infinite-capacity storage system. The cumulative input to the system is assumed to be either (a) a non-decreasing Lévy process or (b) an integrated continuous-time Markov chain. Reward accumulates at a rate depending on the instantaneous release rate. The objective is to choose the release rule in such a way as to maximize the expected total discounted return. In this note we show how to determine the expected discounted return when the release rate is either constant or a linear function of the content.  相似文献   

地震安全设防中的若干问题(Ⅰ)——地震区建筑规范未解决的问题     

李大华 《中国地震》1993,(1)

本文简要地回顾了我国早期的地震区建筑规范,初步讨论了地震小区划与规范的连接,设防烈度的演进,结构施工验收动力特性无损检测问题,内容涉及到技术和管理两个方面。  相似文献   

Pathways of Influence of the Northern Hemisphere Mid–high Latitudes on East Asian Climate: A Review   总被引：7，自引：0，他引：7  

Jianping LI  Fei ZHENG  Cheng SUN  Juan FENG  Jing WANG 《大气科学进展》2019,36(9):902-921

This paper reviews recent progress made by Chinese scientists on the pathways of influence of the Northern Hemisphere mid–high latitudes on East Asian climate within the framework of a "coupled oceanic–atmospheric(land–atmospheric or seaice–atmospheric) bridge" and "chain coupled bridge". Four major categories of pathways are concentrated upon, as follows:Pathway A—from North Atlantic to East Asia; Pathway B—from the North Pacific to East Asia; Pathway C—from the Arctic to East Asia; and Pathway D—the synergistic effects of the mid–high latitudes and tropics. In addition, definitions of the terms "combined effect", "synergistic effect" and "antagonistic effect" of two or more factors of influence or processes and their criteria are introduced, so as to objectively investigate those effects in future research.  相似文献   

Criteria for effective zero-deforestation commitments     

《Global Environmental Change》2019

Zero-deforestation commitments are a type of voluntary sustainability initiative that companies adopt to signal their intention to reduce or eliminate deforestation associated with commodities that they produce, trade, and/or sell. Because each company defines its own zero-deforestation commitment goals and implementation mechanisms, commitment content varies widely. This creates challenges for the assessment of commitment implementation or effectiveness. Here, we develop criteria to assess the potential effectiveness of zero-deforestation commitments at reducing deforestation within a company supply chain, regionally, and globally. We apply these criteria to evaluate 52 zero-deforestation commitments made by companies identified by Forest 500 as having high deforestation risk. While our assessment indicates that existing commitments converge with several criteria for effectiveness, they fall short in a few key ways. First, they cover just a small share of the global market for deforestation-risk commodities, which means that their global impact is likely to be small. Second, biome-wide implementation is only achieved in the Brazilian Amazon. Outside this region, implementation occurs mainly through certification programs, which are not adopted by all producers and lack third-party near-real time deforestation monitoring. Additionally, around half of all commitments include zero-net deforestation targets and future implementation deadlines, both of which are design elements that may reduce effectiveness. Zero-net targets allow promises of future reforestation to compensate for current forest loss, while future implementation deadlines allow for preemptive clearing. To increase the likelihood that commitments will lead to reduced deforestation across all scales, more companies should adopt zero-gross deforestation targets with immediate implementation deadlines and clear sanction-based implementation mechanisms in biomes with high risk of forest to commodity conversion.  相似文献   

民用P(Y)码伪距的精度分析及其在单点定位中的应用     

范士杰  郭际明 《测绘工程》2007,16(4):63-66

民用GPS双频接收机主要采用互相关技术和Z跟踪技术消除或减弱A-S(Anti-Spoofing)的影响,获取P(Y)码伪距观测值。文中对两种技术获取的P(Y)码伪距的精度进行了理论分析和实测数据的验证。民用GPS双频接收机获取P(Y)码伪距的意义在于消除或减弱电离层延迟误差的影响,进而提高定位的精度,文中结合单点定位给出了例证。  相似文献