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Pijush Samui 《地震工程与工程振动(英文版)》2007,6(4):331-336
Determining the liquefaction potential of soil is important in earthquake engineering. This study proposes the use of the Relevance Vector Machine (RVM) to determine the liquefaction potential of soil by using actual cone penetration test (CPT) data. RVM is based on a Bayesian formulation of a linear model with an appropriate prior that results in a sparse representation. The results are compared with a widely used artifi cial neural network (ANN) model. Overall, the RVM shows good performance and is proven to be more accurate than the ANN model. It also provides probabilistic output. The model provides a viable tool for earthquake engineers to assess seismic conditions for sites that are susceptible to liquefaction. 相似文献
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Collaboration Across Borders: Moving Beyond Positionality 总被引：2，自引：0，他引：2
Discussions about collaborative spaces in postcolonial feminist and geographical analyses have often hinged on questions of positionality, reflexivity and identity, largely in relation to the politics of representation. Such approaches have often led to an impasse, especially in fieldwork-based feminist research, where reflexivity has mainly focused on examining the identities of the individual researcher rather than on the ways in which those identities intersect with institutional, geopolitical and material aspects of their positionality. This kind of identity-based reflexivity does not distinguish systematically between the ethical, ontological and epistemological aspects of fieldwork dilemmas; it also fails to adequately address how our ability to align our theoretical priorities with the concerns of communities whose struggles we want to advance is connected to the opportunities, constraints and values embedded in our academic institutions. This article takes this discussion forward by arguing for a postcolonial and transnational feminist praxis that focuses explicitly and deliberately on (a) conceptualising and implementing collaborative efforts that insist on crossing multiple and difficult borders; (b) the sites, strategies and skills deployed to produce such collaborations; and (c) the specific processes through which such collaborations can find their form, content and meaning. To ground this discussion, I draw upon two collaborative initiatives that I have begun recently in the state of Uttar Pradesh, north India. 相似文献
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通过选取阿拉善地区3个典型霸王群落为研究对象,研究霸王器官间(根、茎、叶)生态化学计量比特征及非结构性碳水化合物(Non-structural carbohydrates,NSCs)的变化,以便加深对霸王生存策略的理解,更好的服务于荒漠生态系统的生态恢复。结果表明:霸王茎和叶中可溶性糖(Solu?ble sugar,SS)、淀粉(Starch,ST)和NSCs含量随干旱加剧均显著降低。根系中SS和NSCs在3个样点间差异不显著,ST先降低后增加,ST含量在Plot3中比在Plot1和Plot2中高19.3%和31.2%。干旱使霸王根、茎、叶中N、P含量显著下降,使根、茎、叶中C:N和C:P显著增高,叶片N:P<14。Plot1中霸王器官间SS、SS:ST和NSCs含量表现为叶片>根>茎,ST含量为茎>根>叶片;Plot2和Plot3中霸王器官间SS、ST和NSCs含量均为根>茎>叶片。3个样点中叶片相较于茎干和根系具有高的N、P含量和低的C:N和C:P。NSCs与C:N:P间的关系表明:根、茎、叶中的N含量与SS正相关,叶片N含量与根系ST负相关。以上结果表明霸王的茎干和根系可能扮演“营养库”的角色,霸王通过提高N、P利用效率来减缓水分亏缺使其生长受到N限制的影响。霸王通过调节器官间NSCs的积累及分配来适应干旱,采取将根系中ST转化为SS来调节渗透势的策略;并随干旱加剧将更多的碳水化合物投资分配到根部,以ST的形式存储,而N是影响霸王根系中ST与SS间转化和ST存储的关键元素。 相似文献
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李晓斌 《大地测量与地球动力学》2022,42(6):588-593
为准确掌握库区滑坡变形潜势,在变形监测成果统计基础上,首先利用极限位移准则开展滑坡现状变形潜势分析;然后以相关向量机为理论基础,通过优化处理保证其参数最优性,构建滑坡变形预测模型,并以预测结果开展滑坡变形潜势的发展趋势评价;最后结合两种分析结果,实现滑坡综合变形潜势分析。结果表明,不同监测点的现状变形潜势状态存在一定差异,由不利原则可知,现状变形潜势等级为Ⅳ级,潜势程度属严重状态;滑坡变形仍会进一步增加,变形潜势趋于不利方向发展。综合两种分析结果可知,滑坡变形潜势处于不利状态,后期失稳可能性较大,应加强灾害防治,避免成灾损失。 相似文献
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古铜陵地区是长江中下游成矿中重要的多金属成矿区,有着独特的多位一体、"层".带"结合、多矿种、多种成因类型复合的成矿地质环境,产生了丰富的接触交代与层控式夕卡岩-热液充填交代的块状硫化物型的铜、金、银、硫等内生矿产,成为国内外地学研究的热点地区.本文从铊元素的地球化学研究探寻其作为金(铜)矿床的探途元素的可能,从本区一些主要矿床中过铊与金(铜)相关性的研究,得出铊与金(铜)密切正相关的结论,并进行了微量元素铊在找矿方面应用的一些初步探读者论坛,指出下一步找矿方向及预测靶区. 相似文献
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袁洪 《广东海洋大学学报》2014,(5):86-90
为提高语言交际效率,作者或发话人往往选择最精简的语言符号表达特定的思想,这就是语言经济原则,它作为规约语言使用的语用机制,对有关语用理论如会话含义理论、关联论和模因论等语用理论具有普遍约束力。 相似文献
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提出一种基于EM算法优化相关向量机(RVM)的BDS-3超快速钟差预报算法。首先,利用组合MAD法预处理钟差数据,并进行一次差分计算;然后,利用钟差一次差分数据对RVM模型进行训练,通过EM算法迭代求取模型的超参数;最后,利用优化后的RVM模型进行数据预测,将钟差一次差分预测值还原,得到钟差预报值。采用iGMAS中心提供的实测BDS-3超快速钟差数据进行预报实验,并将本文模型与QP模型、SA模型及iGMAS超快速钟差预报产品(ISU-P)结果进行对比分析。结果表明,对于6 h、12 h和24 h预报,本文模型预报BDS-3卫星钟差数据的平均精度均优于0.61 ns;与ISU-P、QP模型和SA模型相比,本文模型预报24 h时精度分别提升64.1%、50.0%和49.2%。 相似文献