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基于空间相量模型的三相电压暂降扰动特征提取与分类 被引量:10
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作者 辛峰 尤向阳 +1 位作者 葛笑寒 马宁 《电力系统保护与控制》 EI CSCD 北大核心 2022年第8期58-65,共8页
对暂降扰动进行精准类型识别是电能质量评估和治理的前提。现有暂降特征提取多是对单一扰动数据进行识别分类,采用数学变换法进行特征提取时数据维数高且计算量大。针对这些问题,提出了一种基于三相电压空间相量模型的多级暂降扰动可视... 对暂降扰动进行精准类型识别是电能质量评估和治理的前提。现有暂降特征提取多是对单一扰动数据进行识别分类,采用数学变换法进行特征提取时数据维数高且计算量大。针对这些问题,提出了一种基于三相电压空间相量模型的多级暂降扰动可视化特征提取及分类方法。首先,将三相电压时域波形数据转换为空间相量模型;其次,使用K-mean算法,将电压降落扰动聚类成平面内可视化的圆或椭圆;最后,利用逻辑回归算法对每一个聚类的圆或椭圆进行特征提取与分类。应用所提方法分别进行了单一扰动和多级扰动识别的仿真实验,结果表明,所提方法能有效识别A、C_(a)、C_(b)、C_(c)、D_(a)、D_(b)和D_(c)等七类电压暂降扰动。该方法降低了数据维度,减少了模型计算量,避免了对动态过渡过程的检测,降低了错误识别的风险,为多级电压暂降扰动的识别与分类提供了一种有效的辅助手段。 展开更多
关键词 空间相量模型 K-mean聚类 逻辑回归算法 电压暂降
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基于卷积神经网络和随机森林的三相电压暂降分类 被引量:32
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作者 刘佳翰 陈克绪 +2 位作者 马建 徐春华 吴建华 《电力系统保护与控制》 EI CSCD 北大核心 2019年第20期112-118,共7页
特征提取是电能质量扰动识别的关键步骤,然而传统的数学变换与浅层神经网络相结合的方法无法自动提取特征。为此,提出了一种基于卷积神经网络(CNN)和随机森林(RF)的混合模型来对三相电压暂降数据进行自动特征提取及分类。首先,将三相电... 特征提取是电能质量扰动识别的关键步骤,然而传统的数学变换与浅层神经网络相结合的方法无法自动提取特征。为此,提出了一种基于卷积神经网络(CNN)和随机森林(RF)的混合模型来对三相电压暂降数据进行自动特征提取及分类。首先,将三相电压暂降数据转换为空间相量模型(SPM);其次,利用CNN对SPM进行特征提取;最后,将RF应用于分类。为了加快CNN训练速度并缓解过拟合,引入了Dropout、学习率指数衰减和自适应矩估计权值更新算法。实验结果表明,与其他分类方法相比,所提方法具有较好的泛化性能和较高的分类准确率,这为电压暂降识别提供了一种客观、高效的辅助手段。 展开更多
关键词 空间相量模型 卷积神经网络 随机森林 电压暂降 电能质量
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PT Symmetric Quantum Models Living in an Auxiliary Pontryagin Space
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作者 Miloslav Znojil 《Journal of Mathematics and System Science》 2012年第2期102-109,共8页
In the traditional theoretical descriptions of microscopic physical systems (typically, atoms and molecules) people strongly relied upon analogies between the classical mechanics and quantum theory. Naturally, such ... In the traditional theoretical descriptions of microscopic physical systems (typically, atoms and molecules) people strongly relied upon analogies between the classical mechanics and quantum theory. Naturally, such a methodical framework proved limited as it excluded, up to the recent past, multiple, less intuitively accessible phenomenological models from the serious consideration. For this reason, the classical-quantum parallels were steadily weakened, preserving still the basic and robust abstract version of the key Copenhagen-school concept of treating the states of microscopic systems as elements of a suitable linear Hilbert space. Less than 20 years ago, finally, powerful innovations emerged on mathematical side. Various less standard representations of the Hilbert space entered the game. Pars pro toto, one might recall the Dyson's representation of the so-called interacting boson model in nuclear physics, or the steady increase of popularity of certain apparently non-Hermitian interactions in field theory. In the first half of the author's present paper the recent heuristic progress as well as phenomenologieal success of the similar use of non-Hermitian Ham iltonians will be reviewed, being characterized by their self-adjoint form in an auxiliary Krein space K. In the second half of the author's text a further extension of the scope of such a mathematically innovative approach to the physical quantum theory is proposed. The author's key idea lies in the recommendation of the use of the more general versions of the indefinite metrics in the space of states (note that in the Krein-space case the corresponding indefinite metric P is mostly treated as operator of parity). Thus, the author proposes that the operators P should be admitted to represent, in general, the indefinite metric in a Pontryagin space. A constructive version of such a generalized quantization strategy is outlined and found feasible. 展开更多
关键词 Quantum mechanics Hermitizations of observables auxiliary Krein and Pontryagin spaces Jacobi-matrix Hamiltonians Dieudonne equation.
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