Function approximation (FA) has been a critical component in solving large zero-sum games. Yet, little attention has been given towards FA in solving \textit{general-sum} extensive-form games, despite them being widely regarded as being computationally more challenging than their fully competitive or cooperative counterparts. A key challenge is that for many equilibria in general-sum games, no simple analogue to the state value function used in Markov Decision Processes and zero-sum games exists. In this paper, we propose learning the \textit{Enforceable Payoff Frontier} (EPF) -- a generalization of the state value function for general-sum games. We approximate the optimal \textit{Stackelberg extensive-form correlated equilibrium} by representing EPFs with neural networks and training them by using appropriate backup operations and loss functions. This is the first method that applies FA to the Stackelberg setting, allowing us to scale to much larger games while still enjoying performance guarantees based on FA error. Additionally, our proposed method guarantees incentive compatibility and is easy to evaluate without having to depend on self-play or approximate best-response oracles.
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Owing to the prohibitive costs of generating large amounts of labeled data, programmatic weak supervision is a growing paradigm within machine learning. In this setting, users design heuristics that provide noisy labels for subsets of the data. These weak labels are combined (typically via a graphical model) to form pseudolabels, which are then used to train a downstream model. In this work, we question a foundational premise of the typical weakly supervised learning pipeline: given that the heuristic provides all ``label" information, why do we need to generate pseudolabels at all? Instead, we propose to directly transform the heuristics themselves into corresponding loss functions that penalize differences between our model and the heuristic. By constructing losses directly from the heuristics, we can incorporate more information than is used in the standard weakly supervised pipeline, such as how the heuristics make their decisions, which explicitly informs feature selection during training. We call our method Losses over Labels (LoL) as it creates losses directly from heuristics without going through the intermediate step of a label. We show that LoL improves upon existing weak supervision methods on several benchmark text and image classification tasks and further demonstrate that incorporating gradient information leads to better performance on almost every task.
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Identifying statistical regularities in solutions to some tasks in multi-task reinforcement learning can accelerate the learning of new tasks. Skill learning offers one way of identifying these regularities by decomposing pre-collected experiences into a sequence of skills. A popular approach to skill learning is maximizing the likelihood of the pre-collected experience with latent variable models, where the latent variables represent the skills. However, there are often many solutions that maximize the likelihood equally well, including degenerate solutions. To address this underspecification, we propose a new objective that combines the maximum likelihood objective with a penalty on the description length of the skills. This penalty incentivizes the skills to maximally extract common structures from the experiences. Empirically, our objective learns skills that solve downstream tasks in fewer samples compared to skills learned from only maximizing likelihood. Further, while most prior works in the offline multi-task setting focus on tasks with low-dimensional observations, our objective can scale to challenging tasks with high-dimensional image observations.
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Finetuning image-text models such as CLIP achieves state-of-the-art accuracies on a variety of benchmarks. However, recent works like WiseFT (Wortsman et al., 2021) and LP-FT (Kumar et al., 2022) have shown that even subtle differences in the finetuning process can lead to surprisingly large differences in the final performance, both for in-distribution (ID) and out-of-distribution (OOD) data. In this work, we show that a natural and simple approach of mimicking contrastive pretraining consistently outperforms alternative finetuning approaches. Specifically, we cast downstream class labels as text prompts and continue optimizing the contrastive loss between image embeddings and class-descriptive prompt embeddings (contrastive finetuning). Our method consistently outperforms baselines across 7 distribution shifts, 6 transfer learning, and 3 few-shot learning benchmarks. On WILDS-iWILDCam, our proposed approach FLYP outperforms the top of the leaderboard by $2.3\%$ ID and $2.7\%$ OOD, giving the highest reported accuracy. Averaged across 7 OOD datasets (2 WILDS and 5 ImageNet associated shifts), FLYP gives gains of $4.2\%$ OOD over standard finetuning and outperforms the current state of the art (LP-FT) by more than $1\%$ both ID and OOD. Similarly, on 3 few-shot learning benchmarks, our approach gives gains up to $4.6\%$ over standard finetuning and $4.4\%$ over the state of the art. In total, these benchmarks establish contrastive finetuning as a simple, intuitive, and state-of-the-art approach for supervised finetuning of image-text models like CLIP. Code is available at https://github.com/locuslab/FLYP.
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本文在完全和时间戳监督的设置中介绍了通过序列(SEQ2SEQ)翻译序列(SEQ2SEQ)翻译的统一框架。与当前的最新帧级预测方法相反,我们将动作分割视为SEQ2SEQ翻译任务,即将视频帧映射到一系列动作段。我们提出的方法涉及在标准变压器SEQ2SEQ转换模型上进行一系列修改和辅助损失函数,以应对与短输出序列相对的长输入序列,相对较少的视频。我们通过框架损失为编码器合并了一个辅助监督信号,并在隐式持续时间预测中提出了单独的对齐解码器。最后,我们通过提出的约束K-Medoids算法将框架扩展到时间戳监督设置,以生成伪分段。我们提出的框架在完全和时间戳监督的设置上始终如一地表现,在几个数据集上表现优于或竞争的最先进。
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当与分支和界限结合使用时,结合的传播方法是正式验证深神经网络(例如正确性,鲁棒性和安全性)的最有效方法之一。但是,现有作品无法处理在传统求解器中广泛接受的切割平面限制的一般形式,这对于通过凸出凸松弛的加强验证者至关重要。在本文中,我们概括了结合的传播程序,以允许添加任意切割平面的约束,包括涉及放宽整数变量的限制,这些变量未出现在现有的结合传播公式中。我们的广义结合传播方法GCP-crown为应用一般切割平面方法}开辟了一个机会进行神经网络验证,同时受益于结合传播方法的效率和GPU加速。作为案例研究,我们研究了由现成的混合整数编程(MIP)求解器生成的切割平面的使用。我们发现,MIP求解器可以生成高质量的切割平面,以使用我们的新配方来增强基于界限的验证者。由于以分支为重点的绑定传播程序和切削平面的MIP求解器可以使用不同类型的硬件(GPU和CPU)并行运行,因此它们的组合可以迅速探索大量具有强切割平面的分支,从而导致强大的分支验证性能。实验表明,与VNN-Comp 2021中最佳工具相比,我们的方法是第一个可以完全求解椭圆形的基准并验证椭圆21基准的两倍的验证者,并且在oval21基准测试中的最佳工具也明显超过了最先进的验证器。广泛的基准。 GCP-Crown是$ \ alpha $,$ \ beta $ -Crown验证者,VNN-COMP 2022获奖者的一部分。代码可在http://papercode.cc/gcp-crown上获得
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测试时间适应(TTA)是指适应神经网络以进行分配变化,仅在测试时间内从新域中访问未标记的测试样本。先前的TTA方法优化了无监督的目标,例如帐篷中的模型预测的熵[Wang等,2021],但目前尚不清楚到底是什么使TTA损失良好。在本文中,我们首先提出一个令人惊讶的现象:如果我们尝试在广泛的功能上衡量最佳的TTA损失,那么我们恢复了与(温度缩放版本的)非常相似的函数帐篷采用的软磁性 - 凝集。但是,只有在我们正在适应的分类器通过跨凝结训练的情况下,这才能保持;如果通过平方损失训练,则会出现不同的最佳TTA损失。为了解释这一现象,我们通过训练损失的凸结合物分析了TTA。我们表明,在自然条件下,这种(无监督的)共轭功能可以看作是对原始监督损失的局部近似值,实际上,它恢复了元学习发现的最佳损失。这导致了一种通用食谱,可用于为通用类的任何给定监督培训损失功能找到良好的TTA损失。从经验上讲,我们的方法始终在广泛的基准测试中统治其他基线。当应用于新型损失功能的分类器时,我们的方法尤其令人感兴趣,例如,最近所传播的polyloss与基于熵的损失有很大的不同。此外,我们表明我们的方法也可以用非常特定的软标签解释为一种自我训练,我们将其称为共轭伪标记。总体而言,我们的方法为更好地理解和改善测试时间适应提供了广泛的框架。代码可在https://github.com/locuslab/tta_conjugate上找到。
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最近,Miller等。结果表明,模型的分布(ID)精度与几个OOD基准上的分布(OOD)精度具有很强的线性相关性 - 一种将它们称为“准确性”的现象。虽然一种用于模型选择的有用工具(即,最有可能执行最佳OOD的模型是具有最高ID精度的模型),但此事实无助于估计模型的实际OOD性能,而无需访问标记的OOD验证集。在本文中,我们展示了一种类似但令人惊讶的现象,也与神经网络分类器对之间的一致性一致:每当在线准确性时,我们都会观察到任何两个神经网络的预测之间的OOD一致性(具有潜在的不同架构)还观察到与他们的ID协议有很强的线性相关性。此外,我们观察到OOD与ID协议的斜率和偏置与OOD与ID准确性的偏差非常匹配。我们称之为“协议”的现象具有重要的实际应用:没有任何标记的数据,我们可以预测分类器的OOD准确性},因为只需使用未标记的数据就可以估算OOD一致性。我们的预测算法在同意在线达成的变化中都优于先前的方法,而且令人惊讶的是,当准确性不在线上时。这种现象还为深度神经网络提供了新的见解:与在线的准确性不同,一致性似乎仅适用于神经网络分类器。
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除了在许多视觉任务中实现高性能外,由于模式之间的冗余信息的可用性,多模式模型对单源故障有预期。在本文中,我们研究了多模式神经网络对单个模态上最坏情况(即对抗性)扰动的鲁棒性。我们首先表明,标准的多模式融合模型容易受到单源对手的影响:对任何单个模式的攻击都可以从多个不受干扰的方式中克服正确的信息,并导致模型失败。这种令人惊讶的脆弱性构成了各种多模式任务,因此需要解决方案。在这一发现的激励下,我们提出了一种对抗性强大的融合策略,该策略训练模型以比较来自所有输入源的信息,检测与其他模式相比,在扰动模式中的不一致之处,并且仅允许来自不受干扰的方式的信息通过。我们的方法在单源鲁棒性方面的最先进方法显着提高,在行动识别方面获得了7.8-25.2%的收益,对象检测的19.7-48.2%和1.6-6.7%的情感分析,而没有降低绩效绩效,在不受干扰的(即清洁)数据上。
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在本文中,我们展示了如何通过仅依靠现成的预审预周化的模型来实现对2型界限的最先进的对抗性鲁棒性。为此,我们实例化了Salman等人的DeNoceed平滑方法。通过结合预处理的降级扩散概率模型和标准的高智分类器。这使我们能够在限制在2个norm范围内的对抗扰动下证明Imagenet上的71%精度,使用任何方法比先前的认证SOTA提高了14个百分点,或改善了与DeNoed Spootering相比的30个百分点。我们仅使用预审预测的扩散模型和图像分类器获得这些结果,而无需进行任何模型参数的任何微调或重新训练。
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