Results 31 to 40 of about 1,549 (163)
Extraction of metamorphic minerals by multiscale segmentation combined with random forest [PDF]
The identification of metamorphic minerals is the basis of metamorphic rock research. Extraction of mineral information by remote sensing technology has been widely used.
Guo-qiang WANG +3 more
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Abstract Forest cover is positively associated with fish biomass and fisheries yield in the Amazon River floodplain, and many species enter flooded forests to feed, spawn, or seek refuge from predation. Floating macrophyte beds, known as floating meadows, in Amazon floodplains support high fish diversity and serve as nursery habitat for many fishes of ...
Sam Grinstead +6 more
wiley +1 more source
针对利用分类器对建筑结构进行损伤识别的问题,引入一种新的组合分类器算法——随机森林,提出基于小波包分解和随机森林的结构损伤识别方法。首先,采用小波包对结构在不同损伤程度和位置上的振动加速度信号进行分解,得到各个频带上的总能量;然后,利用各频带上能量值存在着差异性作为输入到分类器的特征向量;最后,训练随机森林模型并对建筑结构的损伤位置和损伤程度进行识别。应用该方法对一座8层剪切型钢框架结构进行损伤判别,并与BP神经网络和支持向量机方法进行对比 ...
周绮凤 +3 more
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Improved Deep Learning Model for Forecasting Short-Term Load Based on Random Forest Algorithm and Rough Set Theory [PDF]
Accurate power load forecasting is conducive to ensuring the safe and economic operation of the power system. Aiming at the problems of low prediction accuracy and long time consuming of the current prediction algorithms, an improved deep learning (DL ...
FENG Jiahuan +6 more
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Read the free Plain Language Summary for this article on the Journal blog. Abstract While elevational patterns of soil bacterial and fungal communities in mountain ecosystems have been well documented, the assembly processes of soil archaeal and protistan communities, and their linkage with ecosystem multifunctionality (EMF), remain poorly understood ...
Bao‐Min Yao +14 more
wiley +1 more source
广东电网遭台风泰利侵袭的输配电设备受损分析及评估 [PDF]
近年来致灾台风频率呈增加趋势,以2023年影响广东电网约百万用户的第4号台风“泰利”为例,分析广东电网遭台风侵袭受灾情况,建立输配电杆塔受损预测模型,识别关键特征变量与因素,为电网防灾减灾提供支持。首先,分析台风“泰利”气象特征,具有“台前对流活跃,风力强度大,降水范围广”等特点,对输配电设备均产生一定程度破坏。其次,利用随机森林、支持向量机、梯度决策树、神经网络等4种机器学习算法建立输配电杆塔受损预测模型,并对比部分算法针对不平衡样本优化前后模型表现。算例表明,随机森林优化后提升最大 ...
侯慧 +5 more
doaj +1 more source
In forests dominated by large clonal plants, such as giant moso bamboo, drought can alter the allocation of newly assimilated C within the tissues of source ramet but may not affect its allocation among interconnected ramets or within plant–soil systems.
Xiaogai Ge +9 more
wiley +1 more source
比较研究了南亚热带鼎湖山森林群落演替序列中马尾松林、针阔混交林和季风常绿阔叶林表层(0~20cm)土壤pH值、有机质、全N、速效K、交换性Ca和Mg、有效P、B、Mo、Cu、Fe、Zn和易还原Mn等营养元素的含量及其相关关系,结果表明:马尾松林土壤pH值显著高于其它两森林土壤;随着群落的进展演替,养分在土壤中的累积(Ca除外)呈不断增加的趋势 ...
欧阳学军 黄忠良 周国逸 褚国伟 李炯 史军辉 徐国良
doaj +2 more sources
高压断路器是电力系统的核心设备,其稳定可靠运行具有重要意义。高压断路器分合闸电流曲线能够很大程度上反映高压断路器分合闸机构的运行状态,因此文中研究了在几种典型故障条件下,断路器分合闸线圈电流的变化。随机森林算法由于算法实现过程中的两次随机过程,使得算法过拟合风险大大降低,模型泛化能力大大增强。提出了使用随机森林算法识别故障电流曲线,取得了很好的效果。
刘芹 +9 more
doaj
The research of machine learning in quantitative investment [PDF]
近些年,量化投资问题受到广泛关注.本文主要探讨机器学习在量化投资领域方 面的应用.本文主要利用决策树算法对中证500成分股进行研究,找出其中具有超额收 益的股票,构建出投资组合.我们应用了SMOTE、CART、RandomForests等机器学习 算法进行模型构建.同时还对比了其他机器学习算法在该数据集上的表现.发现我们 的算法具有较好的表现.In recent years, the issue of quantitative investment has been widely concerned ...
赵汝鑫
core

