排序方式: 共有85条查询结果,搜索用时 15 毫秒
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Building more realistic reservoir optimization models using data mining - A case study of Shelbyville Reservoir 总被引:1,自引:0,他引:1
Mohamad I. HejaziXiming Cai 《Advances in water resources》2011,34(6):701-717
In this paper, we promote a novel approach to develop reservoir operation routines by learning from historical hydrologic information and reservoir operations. The proposed framework involves a knowledge discovery step to learn the real drivers of reservoir decision making and to subsequently build a more realistic (enhanced) model formulation using stochastic dynamic programming (SDP). The enhanced SDP model is compared to two classic SDP formulations using Lake Shelbyville, a reservoir on the Kaskaskia River in Illinois, as a case study. From a data mining procedure with monthly data, the past month’s inflow (Qt−1), current month’s inflow (Qt), past month’s release (Rt−1), and past month’s Palmer drought severity index (PDSIt−1) are identified as important state variables in the enhanced SDP model for Shelbyville Reservoir. When compared to a weekly enhanced SDP model of the same case study, a different set of state variables and constraints are extracted. Thus different time scales for the model require different information. We demonstrate that adding additional state variables improves the solution by shifting the Pareto front as expected while using new constraints and the correct objective function can significantly reduce the difference between derived policies and historical practices. The study indicates that the monthly enhanced SDP model resembles historical records more closely and yet provides lower expected average annual costs than either of the two classic formulations (25.4% and 4.5% reductions, respectively). The weekly enhanced SDP model is compared to the monthly enhanced SDP, and it shows that acquiring the correct temporal scale is crucial to model reservoir operation for particular objectives. 相似文献
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针对语义鸿沟问题,将基于语义特征挖掘模型与支持向量机相关反馈方法相结合,建立了基于支持向量机相关反馈的人机交互遥感影像语义检索系统。实验结果表明,该方法利用高层语义特征及人机交互反馈信息缩小了语义鸿沟,提高了影像检索的精度。 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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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