半监督学习(SSL)是使用不仅标记的示例,而且是未标记的示例学习预测模型的常见方法。尽管用于分类和回归的简单任务的SSL受到了研究社区的广泛关注,但对于具有结构依赖变量的复杂预测任务,这尚未得到适当的研究。这种情况是多标签分类和分层多标签分类任务,可能需要其他信息,可能来自未标记示例提供的描述性空间中的基础分布,以更好地面对同时预测多个类别标签的挑战性任务。在本文中,我们研究了这一方面,并​​提出了一种基于对预测性聚类树的半监督学习的(分层)多标签分类方法。我们还扩展了整体学习的方法,并提出了一种基于随机森林方法的方法。在23个数据集上进行的广泛实验评估显示了该方法的显着优势及其在其监督对应物方面的扩展。此外,该方法可保留可解释性并降低基于经典树模型的时间复杂性。
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Computational units in artificial neural networks follow a simplified model of biological neurons. In the biological model, the output signal of a neuron runs down the axon, splits following the many branches at its end, and passes identically to all the downward neurons of the network. Each of the downward neurons will use their copy of this signal as one of many inputs dendrites, integrate them all and fire an output, if above some threshold. In the artificial neural network, this translates to the fact that the nonlinear filtering of the signal is performed in the upward neuron, meaning that in practice the same activation is shared between all the downward neurons that use that signal as their input. Dendrites thus play a passive role. We propose a slightly more complex model for the biological neuron, where dendrites play an active role: the activation in the output of the upward neuron becomes optional, and instead the signals going through each dendrite undergo independent nonlinear filterings, before the linear combination. We implement this new model into a ReLU computational unit and discuss its biological plausibility. We compare this new computational unit with the standard one and describe it from a geometrical point of view. We provide a Keras implementation of this unit into fully connected and convolutional layers and estimate their FLOPs and weights change. We then use these layers in ResNet architectures on CIFAR-10, CIFAR-100, Imagenette, and Imagewoof, obtaining performance improvements over standard ResNets up to 1.73%. Finally, we prove a universal representation theorem for continuous functions on compact sets and show that this new unit has more representational power than its standard counterpart.
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Generative Adversarial Networks (GANs) have paved the path towards entirely new media generation capabilities at the forefront of image, video, and audio synthesis. However, they can also be misused and abused to fabricate elaborate lies, capable of stirring up the public debate. The threat posed by GANs has sparked the need to discern between genuine content and fabricated one. Previous studies have tackled this task by using classical machine learning techniques, such as k-nearest neighbours and eigenfaces, which unfortunately did not prove very effective. Subsequent methods have focused on leveraging on frequency decompositions, i.e., discrete cosine transform, wavelets, and wavelet packets, to preprocess the input features for classifiers. However, existing approaches only rely on isotropic transformations. We argue that, since GANs primarily utilize isotropic convolutions to generate their output, they leave clear traces, their fingerprint, in the coefficient distribution on sub-bands extracted by anisotropic transformations. We employ the fully separable wavelet transform and multiwavelets to obtain the anisotropic features to feed to standard CNN classifiers. Lastly, we find the fully separable transform capable of improving the state-of-the-art.
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部署AI驱动的系统需要支持有效人类互动的值得信赖的模型,超出了原始预测准确性。概念瓶颈模型通过在类似人类的概念的中间级别调节分类任务来促进可信度。这使得人类干预措施可以纠正错误预测的概念以改善模型的性能。但是,现有的概念瓶颈模型无法在高任务准确性,基于概念的强大解释和对概念的有效干预措施之间找到最佳的妥协,尤其是在稀缺完整和准确的概念主管的现实情况下。为了解决这个问题,我们提出了概念嵌入模型,这是一种新型的概念瓶颈模型,它通过学习可解释的高维概念表示形式而超出了当前的准确性-VS解关性权衡。我们的实验表明,嵌入模型(1)达到更好或竞争性的任务准确性W.R.T. W.R.T.没有概念的标准神经模型,(2)提供概念表示,以捕获有意义的语义,包括其地面真相标签,(3)支持测试时间概念干预措施,其在测试准确性中的影响超过了标准概念瓶颈模型,以及(4)规模对于稀缺的完整概念监督的现实条件。
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卷积神经网络(CNN)的一个问题是,它们需要大型数据集来获得足够的鲁棒性。在小型数据集上,它们容易过度拟合。已经提出了许多方法来克服CNN的缺点。如果无法轻易收集其他样本,则一种常见的方法是使用增强技术从现有数据中生成更多数据点。在图像分类中,许多增强方法都使用简单的图像操纵算法。在这项工作中,我们通过添加通过组合14种增强方法生成的图像来构建合奏,其中第一次提出了其中三种。这些新型方法基​​于傅立叶变换(FT),ra transform(RT)和离散余弦变换(DCT)。预处理的RESNET50网络在训练集上进行了填充,其中包括从每种增强方法中得出的图像。这些网络和几个融合均在11个基准测试中进行了评估和比较。结果表明,通过组合不同的数据增强方法来产生分类器,这些分类器不仅可以与最新技术竞争,而且经常超过文献中报告的最佳方法,从而在数据级上建立合奏。
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随着由于排名引起的复杂几何结构而增加的对象的数量,许多排名数据的算法在计算上变得棘手。部分排名提出了一个额外的挑战,即首选项仅因所有对象的子集而闻名的排名。由于这些原因,最先进的方法无法扩展到现实世界中的应用程序,例如推荐系统。我们通过利用排名数据的几何结构以及有关对象的其他可用信息来解决这一挑战,以根据绘制剪切函数得出用于排名的内核。该图切割内核结合了子解体优化的效率与基于内核方法的理论特性。该图切割内核结合了子解体优化的效率与基于内核方法的理论特性。
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音频数据增强是培训深度神经网络以解决音频分类任务的关键步骤。在本文中,我们在Matlab中引入了一个新型音频数据增强库的录音机。我们为RAW音频数据提供了15种不同的增强算法,8用于频谱图。我们有效地实施了几种增强技术,其有用性在文献中被广泛证明。据我们所知,这是最大的Matlab音频数据增强图书馆可自由使用。我们验证了我们在ESC-50数据集上评估它们的算法的效率。可以在https://github.com/lorisnanni/audiogmenter下载工具箱及其文档。
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