这项工作提出了一种用于概率分类器的新算法的Proboost。该算法使用每个训练样本的认知不确定性来确定最具挑战性/不确定的样本。然后,对于下一个弱学习者,这些样本的相关性就会增加,产生序列,该序列逐渐侧重于发现具有最高不确定性的样品。最后,将弱学习者的输出组合成分类器的加权集合。提出了三种方法来操纵训练集:根据弱学习者估计的不确定性,取样,过采样和加权训练样本。此外,还研究了有关集成组合的两种方法。本文所考虑的弱学习者是标准的卷积神经网络,而不确定性估计使用的概率模型则使用变异推理或蒙特卡洛辍学。在MNIST基准数据集上进行的实验评估表明,ProbOOST可以显着改善性能。通过评估这项工作中提出的相对可实现的改进,进一步强调了结果,该指标表明,只有四个弱学习者的模型导致该指标的改进超过12%(出于准确性,灵敏度或特异性),与没有探针的模型相比。
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近年来,机器学习算法在多种高风险决策应用程序中变得无处不在。机器学习算法从数据中学习模式的无与伦比的能力也使它们能够融合嵌入的偏差。然后,一个有偏见的模型可以做出不成比例地损害社会中某些群体的决策 - 例如,他们获得金融服务的机会。对这个问题的认识引起了公平ML领域,该领域的重点是研究,衡量和缓解算法预测的不公平性,相对于一组受保护的群体(例如种族或性别)。但是,算法不公平的根本原因仍然难以捉摸,研究人员在指责ML算法或训练的数据之间进行了划分。在这项工作中,我们坚持认为,算法不公平源于数据中模型与偏见之间的相互作用,而不是源于其中任何一个的孤立贡献。为此,我们提出了一种分类法来表征数据偏差,并研究了一系列关于公平盲目的ML算法在不同数据偏见设置下表现出的公平性准确性权衡的假设。在我们的现实帐户开放欺诈用例中,我们发现每个设置都需要特定的权衡,从而影响了预期价值和差异的公平性 - 后者通常没有注意到。此外,我们展示了算法在准确性和公平性方面如何根据影响数据的偏差进行比较。最后,我们注意到,在特定的数据偏见条件下,简单的预处理干预措施可以成功平衡小组错误率,而在更复杂的设置中相同的技术失败。
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人类AI合作(HAIC)在决策中的合作旨在在人类决策者和AI系统之间建立协同团队。学会推迟(L2D)已作为一个有前途的框架,以确定人类中的谁和人工智能应采取哪些决定,以优化联合系统的性能和公平性。然而,L2D需要几个通常不可行的要求,例如,人类对每个实例的预测可用性,或独立于上述决策者的地面标签。此外,L2D和其他方法都没有解决在现实世界中部署HAIC的基本问题,例如能力管理或处理动态环境。在本文中,我们旨在识别和审查这些局限性和其他局限性,指出HAIC未来研究的机会可能会在哪里。
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机器学习算法从数据中学习模式的无与伦比的能力也使它们能够融合嵌入的偏差。然后,一个有偏见的模型可以做出不成比例地损害社会中某些群体的决定。在静态ML环境中,大多数现实世界中大多数用例运行的动态预测案例都没有用于衡量静态ML环境中的不公平性。在后者中,预测模型本身在塑造数据的分布中起着关键作用。但是,很少注意将不公平与这些互动联系起来。因此,为了进一步理解这些环境中的不公平性,我们提出了一种分类法来表征数据中的偏见,并研究其由模型行为塑造的案例。以现实世界的开头欺诈检测案例研究为例,我们研究了表演性预测中两个典型偏见的性能和公平性的危险:分配变化以及选择性标签的问题。
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指数族在机器学习中广泛使用,包括连续和离散域中的许多分布(例如,通过SoftMax变换,Gaussian,Dirichlet,Poisson和分类分布)。这些家庭中的每个家庭的分布都有固定的支持。相比之下,对于有限域而言,最近在SoftMax稀疏替代方案(例如Sparsemax,$ \ alpha $ -entmax和Fusedmax)的稀疏替代方案中导致了带有不同支持的分布。本文基于几种技术贡献,开发了连续分布的稀疏替代方案:首先,我们定义了$ \ omega $ regultion的预测图和任意域的Fenchel-young损失(可能是无限或连续的)。对于线性参数化的家族,我们表明,Fenchel-Young损失的最小化等效于统计的矩匹配,从而概括了指数家族的基本特性。当$ \ omega $是带有参数$ \ alpha $的Tsallis negentropy时,我们将获得````trabormed rompential指数)'',其中包括$ \ alpha $ -entmax和sparsemax和sparsemax($ \ alpha = 2 $)。对于二次能量函数,产生的密度为$ \ beta $ -Gaussians,椭圆形分布的实例,其中包含特殊情况,即高斯,双重量级,三人级和epanechnikov密度,我们为差异而得出了差异的封闭式表达式, Tsallis熵和Fenchel-Young损失。当$ \ Omega $是总变化或Sobolev正常化程序时,我们将获得Fusedmax的连续版本。最后,我们引入了连续的注意机制,从\ {1、4/3、3/3、3/2、2 \} $中得出有效的梯度反向传播算法。使用这些算法,我们证明了我们的稀疏连续分布,用于基于注意力的音频分类和视觉问题回答,表明它们允许参加时间间隔和紧凑区域。
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Diabetic Retinopathy (DR) is a leading cause of vision loss in the world, and early DR detection is necessary to prevent vision loss and support an appropriate treatment. In this work, we leverage interactive machine learning and introduce a joint learning framework, termed DRG-Net, to effectively learn both disease grading and multi-lesion segmentation. Our DRG-Net consists of two modules: (i) DRG-AI-System to classify DR Grading, localize lesion areas, and provide visual explanations; (ii) DRG-Expert-Interaction to receive feedback from user-expert and improve the DRG-AI-System. To deal with sparse data, we utilize transfer learning mechanisms to extract invariant feature representations by using Wasserstein distance and adversarial learning-based entropy minimization. Besides, we propose a novel attention strategy at both low- and high-level features to automatically select the most significant lesion information and provide explainable properties. In terms of human interaction, we further develop DRG-Net as a tool that enables expert users to correct the system's predictions, which may then be used to update the system as a whole. Moreover, thanks to the attention mechanism and loss functions constraint between lesion features and classification features, our approach can be robust given a certain level of noise in the feedback of users. We have benchmarked DRG-Net on the two largest DR datasets, i.e., IDRID and FGADR, and compared it to various state-of-the-art deep learning networks. In addition to outperforming other SOTA approaches, DRG-Net is effectively updated using user feedback, even in a weakly-supervised manner.
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In the Earth's magnetosphere, there are fewer than a dozen dedicated probes beyond low-Earth orbit making in-situ observations at any given time. As a result, we poorly understand its global structure and evolution, the mechanisms of its main activity processes, magnetic storms, and substorms. New Artificial Intelligence (AI) methods, including machine learning, data mining, and data assimilation, as well as new AI-enabled missions will need to be developed to meet this Sparse Data challenge.
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Very few eXplainable AI (XAI) studies consider how users understanding of explanations might change depending on whether they know more or less about the to be explained domain (i.e., whether they differ in their expertise). Yet, expertise is a critical facet of most high stakes, human decision making (e.g., understanding how a trainee doctor differs from an experienced consultant). Accordingly, this paper reports a novel, user study (N=96) on how peoples expertise in a domain affects their understanding of post-hoc explanations by example for a deep-learning, black box classifier. The results show that peoples understanding of explanations for correct and incorrect classifications changes dramatically, on several dimensions (e.g., response times, perceptions of correctness and helpfulness), when the image-based domain considered is familiar (i.e., MNIST) as opposed to unfamiliar (i.e., Kannada MNIST). The wider implications of these new findings for XAI strategies are discussed.
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We extend best-subset selection to linear Multi-Task Learning (MTL), where a set of linear models are jointly trained on a collection of datasets (``tasks''). Allowing the regression coefficients of tasks to have different sparsity patterns (i.e., different supports), we propose a modeling framework for MTL that encourages models to share information across tasks, for a given covariate, through separately 1) shrinking the coefficient supports together, and/or 2) shrinking the coefficient values together. This allows models to borrow strength during variable selection even when the coefficient values differ markedly between tasks. We express our modeling framework as a Mixed-Integer Program, and propose efficient and scalable algorithms based on block coordinate descent and combinatorial local search. We show our estimator achieves statistically optimal prediction rates. Importantly, our theory characterizes how our estimator leverages the shared support information across tasks to achieve better variable selection performance. We evaluate the performance of our method in simulations and two biology applications. Our proposed approaches outperform other sparse MTL methods in variable selection and prediction accuracy. Interestingly, penalties that shrink the supports together often outperform penalties that shrink the coefficient values together. We will release an R package implementing our methods.
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Machine learning (ML) has found broad applicability in quantum information science in topics as diverse as experimental design, state classification, and even studies on quantum foundations. Here, we experimentally realize an approach for defining custom prior distributions that are automatically tuned using ML for use with Bayesian quantum state estimation methods. Previously, researchers have looked to Bayesian quantum state tomography due to its unique advantages like natural uncertainty quantification, the return of reliable estimates under any measurement condition, and minimal mean-squared error. However, practical challenges related to long computation times and conceptual issues concerning how to incorporate prior knowledge most suitably can overshadow these benefits. Using both simulated and experimental measurement results, we demonstrate that ML-defined prior distributions reduce net convergence times and provide a natural way to incorporate both implicit and explicit information directly into the prior distribution. These results constitute a promising path toward practical implementations of Bayesian quantum state tomography.
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