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21.
为了提高AVO(amplitude versus offset)反演结果的精度和横向连续性,本文提出了一种新的AVO反演约束方法,该方法结合贝叶斯原理和卡尔曼滤波算法实现了对反演参数纵向和横向的同时约束.文章首先结合反演参数的纵向贝叶斯先验概率约束和反演参数的横向连续性假设建立了与卡尔曼滤波算法对应的AVO反演系统的数学模型,然后将该数学模型代入卡尔曼滤波算法框架,利用卡尔曼滤波算法实现了双向约束AVO反演.二维模型测试和实际数据测试结果表明,相对于单纯的纵向贝叶斯先验概率约束,双向约束能更准确地刻画参数的横向变化,得到更准确、横向连续性更好的反演结果.
相似文献22.
地震波阻抗反演是一种基于地震数据得到波阻抗参数的非线性优化问题。不依赖于目标函数梯度信息的全局优化算法是求解地震波阻抗反演问题的有效方法。然而这类方法采用逐道反演的策略,忽略了相邻地震道的空间相关性,导致反演结果的横向连续性差。针对该问题,提出了一种融入旁道最优解的模型空间初始化方法约束波阻抗反演的搜索空间范围,以改善反演结果的横向连续性,进而提出了一种带有横向约束的多组变异差分进化地震波阻抗反演方法。合成地震记录算例表明,该方法相比于传统方法不仅具有更快的收敛速度,而且反演结果具有更好的横向连续性。此外,该方法被应用于胜利油田某区块的储层波阻抗参数反演,反演结果与测井资料有很好的一致性,且有效地刻画了储层砂岩厚度。 相似文献
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用一维水力学方程求取泻湖水位及潮汐汊道断面流速——以海南陵水新村港为例 总被引:3,自引:0,他引:3
本文通过一维水力学运动方程及连续性方程,得出一个反映泻湖水位变化的二阶非线性有阻尼的强迫振动方程,采用龙格-库特四步格式进行求解,并以海南陵水新村港为例,计算了泻湖水位及潮汐汊道的断面流速.研究结果表明:(1)一维水力学方程可容易地求得泻湖-潮汐汊道体系中泻湖内的水位及汊道的断面流速,计算简单快捷.(2)一维水力学方程可分析潮汐汊道体系中的一些基本现象.如潮汐汊道对潮波的"过滤器"特征;由于泻湖-潮汐汊道体系的阻尼系数较大所导致的潮波自外向泻湖传播时衰减剧烈;径流对泻湖水位及汊道流速产生有利于落潮优势的影响;风可使泻湖水位抬升或下降等.(3)无论是否考虑泻湖与潮汐汊道面积随水位的变化,一维水力学方程都具有相当大的缺陷.由于其不能反映泻湖内地形的空间变化,也不能解决漫滩与归槽等过程,在外海潮波无次生波的情况下,它本身不能产生次生潮波,因而不能正确地反映潮汐汊道体系的涨落潮历时与流速不对称,从而不能分析泥沙的净输运及潮汐汊道的稳定性问题.(4)新村港泻湖-潮汐汊道体系中潮汐汊道的断面面积大小对整个体系的稳定性及演变趋势起着控制作用. 相似文献
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Anita Moldenhauer-Roth Guillaume Piton Sebastian Schwindt Mona Jafarnejad Anton JSchleiss 《国际泥沙研究》2021,36(1):136-150
Sediment detention basins are implemented on mountain rivers to trap solid material that may aggravate the flooding of downstream settlements.However,retention structures built in the past may unnecessarily retain sediment during non-hazardous flood events,resulting in high maintenance costs and sediment deficit downstream.In addition,the so-called spontaneous self-flushing of previously retained sediment during floods has occasionally been observed.Recent research suggests to design sediment detention basins for controlling sediment passage with a guiding channel across the deposition area upstream of a hybrid barrier.Such barriers consist of a check dam with a slot orifice and an upstream bar screen with a bottom clearance in order to benefit from a combined mechanical-hydraulic retention control.The present paper enhances this pioneering research with the help of new experimental data,including a wide range of sediment mixtures and large wood,as well as variable barrier heights.Improved design criteria are provided regarding the bar screen and the basin storage capacity.The functionality of the enhanced concept for sediment detention is illustrated by a case study on a physical model:the protection of the Villard-Bonnot village(France)against torrential hazards. 相似文献
26.
《Norsk geografisk tidsskrift. Norwegian journal of geography》2012,66(3):166-172
This paper focuses on the 'cultural turn' which has taken place in British and to a lesser extent North American and Australian human geography in the last decade. It begins by exploring what constitutes the cultural in what has been dubbed 'new cultural geography'. It then explores contemporary claims that cultural geography has eclipsed or marginalised social geography. The final section evaluates these claims about the demise of the social, arguing that the social has not been evacuated but rather has been redefined. While this paper tells a specific story about a particular tradition and geographical frame of reference, it nonetheless has wider relevance because it provides an example of the differential development of particular sub-disciplinary areas, of the way subdisciplinary knowledges shape each other, and of the way understandings of disciplinary trends are contested. 相似文献
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通过对赋存于似层状结构玄武岩岩体中随机发育缓倾角软弱结构面的厚度、间距及连通状况的调查,分析了缓倾角软弱结构面对相应基本岩体强度参数各向异性的影响,并探讨了缓倾角软弱结构面连通率的求解方法,最后通过“连通率”和“厚度加权”法得到了水平和垂直的强度参数值。 相似文献
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相邻的多片 Bezier曲面拼接时 ,在边界处容易引起连续性问题。作者提出了一种方法 ,通过构造逼近曲面片 ,在相邻的四片曲面片边界及交点处达到 C1连续。该方法的关键点在于确定交点周围曲面片上相互关联的四个 Bezier控制点 ,使得曲面片在交点处达到 C1连续 ,并给出了逼近曲面片与原曲面片误差比较公式及误差估计方法 相似文献
30.
For many Indigenous Peoples in the Circumpolar North, cultural engagement and continuity across generations is directly related to relationships between and among people, animals, and landscapes. However, minimal research outlines the emotional responses and disruptions to culture and identity that are driven by ecological change, and the subsequent cultural dimensions of coping and adapting to this uncertainty. Through a case study that explores how caribou population declines and a caribou hunting ban are impacting Inuit in the Nunatsiavut and NunatuKavut regions of Labrador, Canada, this article examines the critical interplay between cultural continuity and adaptive capacity for responding to ecological uncertainty. More specifically, this study: 1) described the central role that caribou play for Inuit emotional wellness, identity, and cultural continuity; 2) explored how the rapid declines of caribou in Labrador are affecting Inuit emotional wellness, identity, and cultural continuity; and 3) characterized the ways in which Inuit are adapting to these emotio-social, cultural, and ecological changes. Drawing from an Inuit-led, multi-year, multi-media qualitative and visual media research program, data from video interviews (n = 84: Nunatsiavut region: n = 54; NunatuKavut region: n = 30) were analyzed using a video-based qualitative analysis, constant-comparative methods, and inductive qualitative approach. Results indicated that caribou are a foundational element for Inuit emotional wellness, identity, and cultural continuity. The changes in caribou populations are resulting in complex emotional responses, losses to cultural meaning and knowledge, and alterations to Inuit identities. The impacts on emotions, identity, and cultural continuity related to Inuit-caribou relations at an individual and collective level reflect the interconnections between cultural continuity and adaptive capacity that underlie the loss of this culturally important species. Though this research focuses on two Inuit groups and caribou in Labrador, the insights from these lived experiences highlight the ongoing cultural and identity consequences associated with species declines occurring globally. 相似文献