Model-based reinforcement learning (RL) methods are appealing in the offline setting because they allow an agent to reason about the consequences of actions without interacting with the environment. Prior methods learn a 1-step dynamics model, which predicts the next state given the current state and action. These models do not immediately tell the agent which actions to take, but must be integrated into a larger RL framework. Can we model the environment dynamics in a different way, such that the learned model does directly indicate the value of each action? In this paper, we propose Contrastive Value Learning (CVL), which learns an implicit, multi-step model of the environment dynamics. This model can be learned without access to reward functions, but nonetheless can be used to directly estimate the value of each action, without requiring any TD learning. Because this model represents the multi-step transitions implicitly, it avoids having to predict high-dimensional observations and thus scales to high-dimensional tasks. Our experiments demonstrate that CVL outperforms prior offline RL methods on complex continuous control benchmarks.
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加权有限自动机(WFA)已广泛应用于许多领域。 WFA的经典问题之一是对离散符号序列的概率分布估计。尽管已扩展了WFA以处理连续输入数据,即连续WFA(CWFA),但由于使用基于WFA的模型,如何将密度函数近似于连续随机变量的序列,这是由于限制了模型的表现。以及通过CWFA的近似密度函数的障碍性。在本文中,我们提出了对CWFA模型的非线性扩展,以提高其表现力,我们将其称为非线性连续WFA(NCWFAS)。然后,我们利用所谓的RNADE方法,该方法是基于神经网络的众所周知的密度估计器,并提出了RNADE-NCWFA模型。 RNADE-NCWFA模型通过设计计算密度函数。我们表明,该模型比CWFA无法近似的高斯HMM模型严格表现得更具表现力。从经验上讲,我们使用高斯HMM生成的数据进行了合成实验。我们专注于评估模型估计长度序列的密度(长度长于训练数据)的能力。我们观察到我们的模型在比较基线方法中表现最好。
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强化学习(RL)代理商广泛用于解决复杂的连续决策任务,但仍然表现出概括到培训期间未见的情景。在先前的在线方法证明,使用超出奖励功能的其他信号可以导致RL代理商中的更好的泛化能力,即使用自我监督学习(SSL),他们在离线RL设置中奋斗,即从静态数据集中学习。我们表明,由于观察之间的相似性差异差,可以在离线设置中阻碍用于RL的普遍的在线算法的性能。我们提出了一种称为广义相似性功能(GSF)的新的理论上动机框架,它使用对比学习来训练基于其预期未来行为的相似性的离线RL代理,以便使用\ EMPH {广义值来量化此相似性。职能}。我们表明GSF足以恢复现有的SSL目标,同时还可以在复杂的离线RL基准,离线Procgen上提高零拍泛化性能。
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Partial differential equations (PDEs) are important tools to model physical systems, and including them into machine learning models is an important way of incorporating physical knowledge. Given any system of linear PDEs with constant coefficients, we propose a family of Gaussian process (GP) priors, which we call EPGP, such that all realizations are exact solutions of this system. We apply the Ehrenpreis-Palamodov fundamental principle, which works like a non-linear Fourier transform, to construct GP kernels mirroring standard spectral methods for GPs. Our approach can infer probable solutions of linear PDE systems from any data such as noisy measurements, or initial and boundary conditions. Constructing EPGP-priors is algorithmic, generally applicable, and comes with a sparse version (S-EPGP) that learns the relevant spectral frequencies and works better for big data sets. We demonstrate our approach on three families of systems of PDE, the heat equation, wave equation, and Maxwell's equations, where we improve upon the state of the art in computation time and precision, in some experiments by several orders of magnitude.
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The unfolding of detector effects is crucial for the comparison of data to theory predictions. While traditional methods are limited to representing the data in a low number of dimensions, machine learning has enabled new unfolding techniques while retaining the full dimensionality. Generative networks like invertible neural networks~(INN) enable a probabilistic unfolding, which map individual events to their corresponding unfolded probability distribution. The accuracy of such methods is however limited by how well simulated training samples model the actual data that is unfolded. We introduce the iterative conditional INN~(IcINN) for unfolding that adjusts for deviations between simulated training samples and data. The IcINN unfolding is first validated on toy data and then applied to pseudo-data for the $pp \to Z \gamma \gamma$ process.
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This paper describes the 5th edition of the Predicting Video Memorability Task as part of MediaEval2022. This year we have reorganised and simplified the task in order to lubricate a greater depth of inquiry. Similar to last year, two datasets are provided in order to facilitate generalisation, however, this year we have replaced the TRECVid2019 Video-to-Text dataset with the VideoMem dataset in order to remedy underlying data quality issues, and to prioritise short-term memorability prediction by elevating the Memento10k dataset as the primary dataset. Additionally, a fully fledged electroencephalography (EEG)-based prediction sub-task is introduced. In this paper, we outline the core facets of the task and its constituent sub-tasks; describing the datasets, evaluation metrics, and requirements for participant submissions.
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The Predicting Media Memorability task in the MediaEval evaluation campaign has been running annually since 2018 and several different tasks and data sets have been used in this time. This has allowed us to compare the performance of many memorability prediction techniques on the same data and in a reproducible way and to refine and improve on those techniques. The resources created to compute media memorability are now being used by researchers well beyond the actual evaluation campaign. In this paper we present a summary of the task, including the collective lessons we have learned for the research community.
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With most technical fields, there exists a delay between fundamental academic research and practical industrial uptake. Whilst some sciences have robust and well-established processes for commercialisation, such as the pharmaceutical practice of regimented drug trials, other fields face transitory periods in which fundamental academic advancements diffuse gradually into the space of commerce and industry. For the still relatively young field of Automated/Autonomous Machine Learning (AutoML/AutonoML), that transitory period is under way, spurred on by a burgeoning interest from broader society. Yet, to date, little research has been undertaken to assess the current state of this dissemination and its uptake. Thus, this review makes two primary contributions to knowledge around this topic. Firstly, it provides the most up-to-date and comprehensive survey of existing AutoML tools, both open-source and commercial. Secondly, it motivates and outlines a framework for assessing whether an AutoML solution designed for real-world application is 'performant'; this framework extends beyond the limitations of typical academic criteria, considering a variety of stakeholder needs and the human-computer interactions required to service them. Thus, additionally supported by an extensive assessment and comparison of academic and commercial case-studies, this review evaluates mainstream engagement with AutoML in the early 2020s, identifying obstacles and opportunities for accelerating future uptake.
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许多机器学习问题在表格域中使用数据。对抗性示例可能对这些应用尤其有害。然而,现有关于对抗鲁棒性的作品主要集中在图像和文本域中的机器学习模型。我们认为,由于表格数据和图像或文本之间的差异,现有的威胁模型不适合表格域。这些模型没有捕获该成本比不可识别更重要,也不能使对手可以将不同的价值归因于通过部署不同的对手示例获得的效用。我们表明,由于这些差异,用于图像的攻击和防御方法和文本无法直接应用于表格设置。我们通过提出新的成本和公用事业感知的威胁模型来解决这些问题,该模型量身定制了针对表格域的攻击者的攻击者的约束。我们介绍了一个框架,使我们能够设计攻击和防御机制,从而导致模型免受成本或公用事业意识的对手的影响,例如,受到一定美元预算约束的对手。我们表明,我们的方法在与对应于对抗性示例具有经济和社会影响的应用相对应的三个表格数据集中有效。
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归纳逻辑编程是基于数学逻辑的机器学习形式,该数学逻辑从给定的示例和背景知识中生成逻辑程序。在此项目中,我们扩展了Popper ILP系统以利用多任务学习。我们实施最新方法和几种新策略来提高搜索性能。此外,我们引入了约束保存,该技术可改善所有方法的整体性能。约束保存使系统可以在背景知识集的更新之间传输知识。因此,我们减少了系统执行的重复工作量。此外,约束保存使我们能够从当前的最新迭代加深搜索方法过渡到更有效的广度首次搜索方法。最后,我们尝试了课程学习技术,并显示了它们对该领域的潜在好处。
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