最小化器和卷积神经网络(CNNS)是两种完全不同的流行技术,其都被用于分析生物序列。在面值,方法看起来完全不同。最小机构在滚动窗口上使用min-wise散列,以提取每个窗口的单个重要的K-MET功能。 CNNS从多个随机初始化的卷积滤波器开始,配对池操作,然后多个附加​​的神经层,以学习滤波器本身以及这些过滤器如何用于对序列进行分类。在本手稿中,我通过仔细的数学分析来证明了散列函数的特性,最小化器和卷积滤波器之间存在深刻的理论连接 - 对于在分类字母表上的序列,具有最大池的卷积滤波器的随机高斯初始化是等效的从随机哈希函数选择最小化器偏向更独特的K-MERS。这提供了CNN在分类序列分析中的不合理效果的局部解释。
translated by 谷歌翻译
高维计算(HDC)是用于数据表示和学习的范式,起源于计算神经科学。HDC将数据表示为高维,低精度向量,可用于学习或召回等各种信息处理任务。高维空间的映射是HDC中的一个基本问题,现有方法在输入数据本身是高维时会遇到可伸缩性问题。在这项工作中,我们探索了一个基于哈希的流媒体编码技术。我们正式表明,这些方法在学习应用程序的性能方面具有可比的保证,同时比现有替代方案更有效。我们在一个流行的高维分类问题上对这些结果进行了实验验证,并表明我们的方法很容易扩展到非常大的数据集。
translated by 谷歌翻译
Deep nets generalize well despite having more parameters than the number of training samples. Recent works try to give an explanation using PAC-Bayes and Margin-based analyses, but do not as yet result in sample complexity bounds better than naive parameter counting. The current paper shows generalization bounds that're orders of magnitude better in practice. These rely upon new succinct reparametrizations of the trained net -a compression that is explicit and efficient. These yield generalization bounds via a simple compression-based framework introduced here. Our results also provide some theoretical justification for widespread empirical success in compressing deep nets.Analysis of correctness of our compression relies upon some newly identified "noise stability"properties of trained deep nets, which are also experimentally verified. The study of these properties and resulting generalization bounds are also extended to convolutional nets, which had eluded earlier attempts on proving generalization.
translated by 谷歌翻译
这项正在进行的工作旨在为统计学习提供统一的介绍,从诸如GMM和HMM等经典模型到现代神经网络(如VAE和扩散模型)缓慢地构建。如今,有许多互联网资源可以孤立地解释这一点或新的机器学习算法,但是它们并没有(也不能在如此简短的空间中)将这些算法彼此连接起来,或者与统计模型的经典文献相连现代算法出现了。同样明显缺乏的是一个单一的符号系统,尽管对那些已经熟悉材料的人(如这些帖子的作者)不满意,但对新手的入境造成了重大障碍。同样,我的目的是将各种模型(尽可能)吸收到一个用于推理和学习的框架上,表明(以及为什么)如何以最小的变化将一个模型更改为另一个模型(其中一些是新颖的,另一些是文献中的)。某些背景当然是必要的。我以为读者熟悉基本的多变量计算,概率和统计以及线性代数。这本书的目标当然不是​​完整性,而是从基本知识到过去十年中极强大的新模型的直线路径或多或少。然后,目标是补充而不是替换,诸如Bishop的\ emph {模式识别和机器学习}之类的综合文本,该文本现在已经15岁了。
translated by 谷歌翻译
这是一门专门针对STEM学生开发的介绍性机器学习课程。我们的目标是为有兴趣的读者提供基础知识,以在自己的项目中使用机器学习,并将自己熟悉术语作为进一步阅读相关文献的基础。在这些讲义中,我们讨论受监督,无监督和强化学习。注释从没有神经网络的机器学习方法的说明开始,例如原理分析,T-SNE,聚类以及线性回归和线性分类器。我们继续介绍基本和先进的神经网络结构,例如密集的进料和常规神经网络,经常性的神经网络,受限的玻尔兹曼机器,(变性)自动编码器,生成的对抗性网络。讨论了潜在空间表示的解释性问题,并使用梦和对抗性攻击的例子。最后一部分致力于加强学习,我们在其中介绍了价值功能和政策学习的基本概念。
translated by 谷歌翻译
Pre-publication draft of a book to be published byMorgan & Claypool publishers. Unedited version released with permission. All relevant copyrights held by the author and publisher extend to this pre-publication draft.
translated by 谷歌翻译
我们建立了量子算法设计与电路下限之间的第一一般连接。具体来说,让$ \ mathfrak {c} $是一类多项式大小概念,假设$ \ mathfrak {c} $可以在统一分布下的成员查询,错误$ 1/2 - \ gamma $通过时间$ t $量子算法。我们证明如果$ \ gamma ^ 2 \ cdot t \ ll 2 ^ n / n $,则$ \ mathsf {bqe} \ nsubseteq \ mathfrak {c} $,其中$ \ mathsf {bqe} = \ mathsf {bque} [2 ^ {o(n)}] $是$ \ mathsf {bqp} $的指数时间模拟。在$ \ gamma $和$ t $中,此结果是最佳的,因为它不难学习(经典)时间$ t = 2 ^ n $(没有错误) ,或在Quantum Time $ t = \ mathsf {poly}(n)$以傅立叶采样为单位为1/2美元(2 ^ { - n / 2})$。换句话说,即使对这些通用学习算法的边际改善也会导致复杂性理论的主要后果。我们的证明在学习理论,伪随机性和计算复杂性的几个作品上构建,并且至关重要地,在非凡的经典学习算法与由Oliveira和Santhanam建立的电路下限之间的联系(CCC 2017)。扩展他们对量子学习算法的方法,结果产生了重大挑战。为此,我们展示了伪随机发电机如何以通用方式意味着学习到较低的连接,构建针对均匀量子计算的第一个条件伪随机发生器,并扩展了Impagliazzo,JaiSwal的本地列表解码算法。 ,Kabanets和Wigderson(Sicomp 2010)通过微妙的分析到量子电路。我们认为,这些贡献是独立的兴趣,可能会发现其他申请。
translated by 谷歌翻译
即使机器学习算法已经在数据科学中发挥了重要作用,但许多当前方法对输入数据提出了不现实的假设。由于不兼容的数据格式,或数据集中的异质,分层或完全缺少的数据片段,因此很难应用此类方法。作为解决方案,我们提出了一个用于样本表示,模型定义和培训的多功能,统一的框架,称为“ Hmill”。我们深入审查框架构建和扩展的机器学习的多个范围范式。从理论上讲,为HMILL的关键组件的设计合理,我们将通用近似定理的扩展显示到框架中实现的模型所实现的所有功能的集合。本文还包含有关我们实施中技术和绩效改进的详细讨论,该讨论将在MIT许可下发布供下载。该框架的主要资产是其灵活性,它可以通过相同的工具对不同的现实世界数据源进行建模。除了单独观察到每个对象的一组属性的标准设置外,我们解释了如何在框架中实现表示整个对象系统的图表中的消息推断。为了支持我们的主张,我们使用框架解决了网络安全域的三个不同问题。第一种用例涉及来自原始网络观察结果的IoT设备识别。在第二个问题中,我们研究了如何使用以有向图表示的操作系统的快照可以对恶意二进制文件进行分类。最后提供的示例是通过网络中实体之间建模域黑名单扩展的任务。在所有三个问题中,基于建议的框架的解决方案可实现与专业方法相当的性能。
translated by 谷歌翻译
Alphazero,Leela Chess Zero和Stockfish Nnue革新了计算机国际象棋。本书对此类引擎的技术内部工作进行了完整的介绍。该书分为四个主要章节 - 不包括第1章(简介)和第6章(结论):第2章引入神经网络,涵盖了所有用于构建深层网络的基本构建块,例如Alphazero使用的网络。内容包括感知器,后传播和梯度下降,分类,回归,多层感知器,矢量化技术,卷积网络,挤压网络,挤压和激发网络,完全连接的网络,批处理归一化和横向归一化和跨性线性单位,残留层,剩余层,过度效果和底漆。第3章介绍了用于国际象棋发动机以及Alphazero使用的经典搜索技术。内容包括minimax,alpha-beta搜索和蒙特卡洛树搜索。第4章展示了现代国际象棋发动机的设计。除了开创性的Alphago,Alphago Zero和Alphazero我们涵盖Leela Chess Zero,Fat Fritz,Fat Fritz 2以及有效更新的神经网络(NNUE)以及MAIA。第5章是关于实施微型α。 Shexapawn是国际象棋的简约版本,被用作为此的示例。 Minimax搜索可以解决六ap峰,并产生了监督学习的培训位置。然后,作为比较,实施了类似Alphazero的训练回路,其中通过自我游戏进行训练与强化学习结合在一起。最后,比较了类似α的培训和监督培训。
translated by 谷歌翻译
Recent work shows that the expressive power of Graph Neural Networks (GNNs) in distinguishing non-isomorphic graphs is exactly the same as that of the Weisfeiler-Lehman (WL) graph test. In particular, they show that the WL test can be simulated by GNNs. However, those simulations involve neural networks for the 'combine' function of size polynomial or even exponential in the number of graph nodes $n$, as well as feature vectors of length linear in $n$. We present an improved simulation of the WL test on GNNs with \emph{exponentially} lower complexity. In particular, the neural network implementing the combine function in each node has only a polylogarithmic number of parameters in $n$, and the feature vectors exchanged by the nodes of GNN consists of only $O(\log n)$ bits. We also give logarithmic lower bounds for the feature vector length and the size of the neural networks, showing the (near)-optimality of our construction.
translated by 谷歌翻译
Low-rank matrix approximations, such as the truncated singular value decomposition and the rank-revealing QR decomposition, play a central role in data analysis and scientific computing. This work surveys and extends recent research which demonstrates that randomization offers a powerful tool for performing low-rank matrix approximation. These techniques exploit modern computational architectures more fully than classical methods and open the possibility of dealing with truly massive data sets.This paper presents a modular framework for constructing randomized algorithms that compute partial matrix decompositions. These methods use random sampling to identify a subspace that captures most of the action of a matrix. The input matrix is then compressed-either explicitly or implicitly-to this subspace, and the reduced matrix is manipulated deterministically to obtain the desired low-rank factorization. In many cases, this approach beats its classical competitors in terms of accuracy, speed, and robustness. These claims are supported by extensive numerical experiments and a detailed error analysis.The specific benefits of randomized techniques depend on the computational environment. Consider the model problem of finding the k dominant components of the singular value decomposition of an m × n matrix. (i) For a dense input matrix, randomized algorithms require O(mn log(k)) floating-point operations (flops) in contrast with O(mnk) for classical algorithms. (ii) For a sparse input matrix, the flop count matches classical Krylov subspace methods, but the randomized approach is more robust and can easily be reorganized to exploit multi-processor architectures. (iii) For a matrix that is too large to fit in fast memory, the randomized techniques require only a constant number of passes over the data, as opposed to O(k) passes for classical algorithms. In fact, it is sometimes possible to perform matrix approximation with a single pass over the data.
translated by 谷歌翻译
虽然注意力成为深度学习的重要机制,但仍然有限的直觉,为什么它工作得很好。在这里,我们表明,在某些数据条件下,变压器注意力与Kanerva稀疏分布式内存(SDM)的某些数据条件密切相关,一种生物合理的关联内存模型。我们确认在预先培训的GPT2变压器模型中满足这些条件。我们讨论了注意力SDM地图的影响,并提供了对关注的新计算和生物学解释。
translated by 谷歌翻译
随机块模型(SBM)是一个随机图模型,其连接不同的顶点组不同。它被广泛用作研究聚类和社区检测的规范模型,并提供了肥沃的基础来研究组合统计和更普遍的数据科学中出现的信息理论和计算权衡。该专着调查了最近在SBM中建立社区检测的基本限制的最新发展,无论是在信息理论和计算方案方面,以及各种恢复要求,例如精确,部分和弱恢复。讨论的主要结果是在Chernoff-Hellinger阈值中进行精确恢复的相转换,Kesten-Stigum阈值弱恢复的相变,最佳的SNR - 单位信息折衷的部分恢复以及信息理论和信息理论之间的差距计算阈值。该专着给出了在寻求限制时开发的主要算法的原则推导,特别是通过绘制绘制,半定义编程,(线性化)信念传播,经典/非背带频谱和图形供电。还讨论了其他块模型的扩展,例如几何模型和一些开放问题。
translated by 谷歌翻译
Graph classification is an important area in both modern research and industry. Multiple applications, especially in chemistry and novel drug discovery, encourage rapid development of machine learning models in this area. To keep up with the pace of new research, proper experimental design, fair evaluation, and independent benchmarks are essential. Design of strong baselines is an indispensable element of such works. In this thesis, we explore multiple approaches to graph classification. We focus on Graph Neural Networks (GNNs), which emerged as a de facto standard deep learning technique for graph representation learning. Classical approaches, such as graph descriptors and molecular fingerprints, are also addressed. We design fair evaluation experimental protocol and choose proper datasets collection. This allows us to perform numerous experiments and rigorously analyze modern approaches. We arrive to many conclusions, which shed new light on performance and quality of novel algorithms. We investigate application of Jumping Knowledge GNN architecture to graph classification, which proves to be an efficient tool for improving base graph neural network architectures. Multiple improvements to baseline models are also proposed and experimentally verified, which constitutes an important contribution to the field of fair model comparison.
translated by 谷歌翻译
我们研究了用于线性回归的主动采样算法,该算法仅旨在查询目标向量$ b \ in \ mathbb {r} ^ n $的少量条目,并将近最低限度输出到$ \ min_ {x \ In \ mathbb {r} ^ d} \ | ax-b \ | $,其中$ a \ in \ mathbb {r} ^ {n \ times d} $是一个设计矩阵和$ \ | \ cdot \ | $是一些损失函数。对于$ \ ell_p $ norm回归的任何$ 0 <p <\ idty $,我们提供了一种基于Lewis权重采样的算法,其使用只需$ \ tilde {o}输出$(1+ \ epsilon)$近似解决方案(d ^ {\ max(1,{p / 2})} / \ mathrm {poly}(\ epsilon))$查询到$ b $。我们表明,这一依赖于$ D $是最佳的,直到对数因素。我们的结果解决了陈和Derezi的最近开放问题,陈和Derezi \'{n} Ski,他们为$ \ ell_1 $ norm提供了附近的最佳界限,以及$ p \中的$ \ ell_p $回归的次优界限(1,2) $。我们还提供了$ O的第一个总灵敏度上限(D ^ {\ max \ {1,p / 2 \} \ log ^ 2 n)$以满足最多的$ p $多项式增长。这改善了Tukan,Maalouf和Feldman的最新结果。通过将此与我们的技术组合起来的$ \ ell_p $回归结果,我们获得了一个使$ \ tilde o的活动回归算法(d ^ {1+ \ max \ {1,p / 2 \}} / \ mathrm {poly}。 (\ epsilon))$疑问,回答陈和德里兹的另一个打开问题{n}滑雪。对于Huber损失的重要特殊情况,我们进一步改善了我们对$ \ tilde o的主动样本复杂性的绑定(d ^ {(1+ \ sqrt2)/ 2} / \ epsilon ^ c)$和非活跃$ \ tilde o的样本复杂性(d ^ {4-2 \ sqrt 2} / \ epsilon ^ c)$,由于克拉克森和伍德拉夫而改善了Huber回归的以前的D ^ 4 $。我们的敏感性界限具有进一步的影响,使用灵敏度采样改善了各种先前的结果,包括orlicz规范子空间嵌入和鲁棒子空间近似。最后,我们的主动采样结果为每种$ \ ell_p $ norm提供的第一个Sublinear时间算法。
translated by 谷歌翻译
神经网络经常将许多无关的概念包装到一个神经元中 - 一种令人困惑的现象被称为“多疾病”,这使解释性更具挑战性。本文提供了一个玩具模型,可以完全理解多义,这是由于模型在“叠加”中存储其他稀疏特征的结果。我们证明了相变的存在,与均匀多型的几何形状的令人惊讶的联系以及与对抗性例子联系的证据。我们还讨论了对机械解释性的潜在影响。
translated by 谷歌翻译
Network data are ubiquitous in modern machine learning, with tasks of interest including node classification, node clustering and link prediction. A frequent approach begins by learning an Euclidean embedding of the network, to which algorithms developed for vector-valued data are applied. For large networks, embeddings are learned using stochastic gradient methods where the sub-sampling scheme can be freely chosen. Despite the strong empirical performance of such methods, they are not well understood theoretically. Our work encapsulates representation methods using a subsampling approach, such as node2vec, into a single unifying framework. We prove, under the assumption that the graph is exchangeable, that the distribution of the learned embedding vectors asymptotically decouples. Moreover, we characterize the asymptotic distribution and provided rates of convergence, in terms of the latent parameters, which includes the choice of loss function and the embedding dimension. This provides a theoretical foundation to understand what the embedding vectors represent and how well these methods perform on downstream tasks. Notably, we observe that typically used loss functions may lead to shortcomings, such as a lack of Fisher consistency.
translated by 谷歌翻译
Whilst deep neural networks have shown great empirical success, there is still much work to be done to understand their theoretical properties. In this paper, we study the relationship between random, wide, fully connected, feedforward networks with more than one hidden layer and Gaussian processes with a recursive kernel definition. We show that, under broad conditions, as we make the architecture increasingly wide, the implied random function converges in distribution to a Gaussian process, formalising and extending existing results by Neal (1996) to deep networks. To evaluate convergence rates empirically, we use maximum mean discrepancy. We then compare finite Bayesian deep networks from the literature to Gaussian processes in terms of the key predictive quantities of interest, finding that in some cases the agreement can be very close. We discuss the desirability of Gaussian process behaviour and review non-Gaussian alternative models from the literature. 1
translated by 谷歌翻译
我们考虑了在高维度中平均分离的高斯聚类混合物的问题。我们是从$ k $身份协方差高斯的混合物提供的样本,使任何两对手段之间的最小成对距离至少为$ \ delta $,对于某些参数$ \ delta> 0 $,目标是恢复这些样本的地面真相聚类。它是分离$ \ delta = \ theta(\ sqrt {\ log k})$既有必要且足以理解恢复良好的聚类。但是,实现这种担保的估计值效率低下。我们提供了在多项式时间内运行的第一算法,几乎符合此保证。更确切地说,我们给出了一种算法,它需要多项式许多样本和时间,并且可以成功恢复良好的聚类,只要分离为$ \ delta = \ oomega(\ log ^ {1/2 + c} k)$ ,任何$ c> 0 $。以前,当分离以k $的分离和可以容忍$ \ textsf {poly}(\ log k)$分离所需的quasi arynomial时间时,才知道该问题的多项式时间算法。我们还将我们的结果扩展到分布的分布式的混合物,该分布在额外的温和假设下满足Poincar \ {e}不等式的分布。我们认为我们相信的主要技术工具是一种新颖的方式,可以隐含地代表和估计分配的​​高度时刻,这使我们能够明确地提取关于高度时刻的重要信息而没有明确地缩小全瞬间张量。
translated by 谷歌翻译
在当前的嘈杂中间尺度量子(NISQ)时代,量子机学习正在成为基于程序门的量子计算机的主要范式。在量子机学习中,对量子电路的门进行了参数化,并且参数是根据数据和电路输出的测量来通过经典优化来调整的。参数化的量子电路(PQC)可以有效地解决组合优化问题,实施概率生成模型并进行推理(分类和回归)。该专着为具有概率和线性代数背景的工程师的观众提供了量子机学习的独立介绍。它首先描述了描述量子操作和测量所必需的必要背景,概念和工具。然后,它涵盖了参数化的量子电路,变异量子本质层以及无监督和监督的量子机学习公式。
translated by 谷歌翻译