Despite the fact that deep neural networks are powerful models and achieve appealing results on many tasks, they are too large to be deployed on edge devices like smartphones or embedded sensor nodes. There have been efforts to compress these networks, and a popular method is knowledge distillation, where a large (teacher) pre-trained network is used to train a smaller (student) network. However, in this paper, we show that the student network performance degrades when the gap between student and teacher is large. Given a fixed student network, one cannot employ an arbitrarily large teacher, or in other words, a teacher can effectively transfer its knowledge to students up to a certain size, not smaller. To alleviate this shortcoming, we introduce multi-step knowledge distillation, which employs an intermediate-sized network (teacher assistant) to bridge the gap between the student and the teacher. Moreover, we study the effect of teacher assistant size and extend the framework to multi-step distillation. Theoretical analysis and extensive experiments on CIFAR-10,100 and ImageNet datasets and on CNN and ResNet architectures substantiate the effectiveness of our proposed approach.

A neural network deployed in the wild may be asked to make predictions for inputs that were drawn from a different distribution than that of the training data. A plethora of work has demonstrated that it is easy to find or synthesize inputs for which a neural network is highly confident yet wrong. Generative models are widely viewed to be robust to such mistaken confidence as modeling the density of the input features can be used to detect novel, out-of-distribution inputs. In this paper we challenge this assumption. We find that the density learned by flow-based models, VAEs, and PixelCNNs cannot distinguish images of common objects such as dogs, trucks, and horses (i.e. CIFAR-10) from those of house numbers (i.e. SVHN), assigning a higher likelihood to the latter when the model is trained on the former. Moreover, we find evidence of this phenomenon when pairing several popular image data sets: FashionMNIST vs MNIST, CelebA vs SVHN, ImageNet vs CIFAR-10 / CIFAR-100 / SVHN. To investigate this curious behavior, we focus analysis on flow-based generative models in particular since they are trained and evaluated via the exact marginal likelihood. We find such behavior persists even when we restrict the flows to constant-volume transformations. These transformations admit some theoretical analysis, and we show that the difference in likelihoods can be explained by the location and variances of the data and the model curvature. Our results caution against using the density estimates from deep generative models to identify inputs similar to the training distribution until their behavior for out-of-distribution inputs is better understood.

Off-policy evaluation (OPE) attempts to predict the performance of counterfactual policies using log data from a different policy. We extend its applicability by developing an OPE method for a class of both full support and deficient support logging policies in contextual-bandit settings. This class includes deterministic bandit (such as Upper Confidence Bound) as well as deterministic decision-making based on supervised and unsupervised learning. We prove that our method's prediction converges in probability to the true performance of a counterfactual policy as the sample size increases. We validate our method with experiments on partly and entirely deterministic logging policies. Finally, we apply it to evaluate coupon targeting policies by a major online platform and show how to improve the existing policy.

随着各种科学领域中数据的越来越多，生成模型在科学方法的每个步骤中都具有巨大的潜力来加速科学发现。他们最有价值的应用也许在于传统上提出假设最慢，最具挑战性的步骤。现在，正在从大量数据中学到强大的表示形式，以产生新的假设，这对从材料设计到药物发现的科学发现应用产生了重大影响。 GT4SD（https://github.com/gt4sd/gt4sd-core）是一个可扩展的开放源库，使科学家，开发人员和研究人员能够培训和使用科学发现中假设生成的最先进的生成模型。 GT4SD支持跨材料科学和药物发现的各种生成模型的用途，包括基于与目标蛋白，OMIC剖面，脚手架距离，结合能等性质的分子发现和设计。

我们提出了一种自我监督的方法，用于预测需要良好牵引力才能导航的轮式移动机器人的可穿越路径。我们的算法称为Wayfast（无路线自动驾驶系统用于遍历性），使用RGB和深度数据以及导航经验，自主在室外非结构化环境中自主生成可遍历的路径。我们的主要灵感是，可以使用动力动力学模型估算滚动机器人的牵引力。使用在线退化的视野估计器提供的牵引力估计值，我们能够以自我监督的方式训练遍历性预测神经网络，而无需以前的方法使用的启发式方法。我们通过在各种环境中进行广泛的现场测试来证明Wayfast的有效性，从沙滩到森林檐篷和积雪覆盖的草田不等。我们的结果清楚地表明，Wayfast可以学会避免几何障碍物以及不可传输的地形，例如雪，这很难避免使用仅提供几何数据（例如LiDAR）的传感器。此外，我们表明，基于在线牵引力估计的培训管道比其他基于启发式的方法更有效率。

多任务学习（MTL）是深度学习中的一个活动字段，其中我们通过利用任务之间的关系来共同学习多项任务。已经证明，与独立学习每个任务时，MTL有助于该模型共享任务之间的学习功能并增强预测。我们为2任务MTL问题提出了一个新的学习框架，它使用一个任务的预测作为另一个网络的输入来预测其他任务。我们定义了由循环一致性损失和对比学习，对齐和跨任务一致性损失的两个新的损失术语。这两个损耗都旨在实施模型以对准多个任务的预测，以便模型一致地预测。理论上我们证明，两次损失都帮助模型更有效地学习，并且在与直接预测的对齐方面更好地了解跨任务一致性损失。实验结果还表明，我们的拟议模型在基准城市景观和NYU数据集上实现了显着性能。

卷积神经网络（CNNS）在许多计算机视觉任务中非常成功。然而，嵌入式和实时系统的推理成本很高，因此有很多关于压缩网络的研究。另一方面，自我关注模型的最新进步表明，卷积滤波器优选在较早层中的自我关注，这表明在较早的层中较强的电感偏差更好。如卷积滤波器所示，强大的偏置可以培训特定的滤波器并将不必要的过滤器构建为零。这类似于经典图像处理任务，其中选择合适的滤波器使得紧凑的字典表示特征。我们遵循这个想法，并将Gabor过滤器合并在较早的CNN层中进行压缩。通过BackProjagation学习Gabor滤波器的参数，因此该功能仅限于Gabor过滤器。我们表明，对于CIFAR-10的第一层VGG-16具有192个内核/功能，但学习Gabor过滤器需要平均29.4内核。此外，在改变的Reset-20上，使用Gabor滤波器，分别在第一和第二层中的平均83％和94％的内核，其中前五层与两层较大的核交换CiFar-10。