We introduce a challenging decision-making task that we call active acquisition for multimodal temporal data (A2MT). In many real-world scenarios, input features are not readily available at test time and must instead be acquired at significant cost. With A2MT, we aim to learn agents that actively select which modalities of an input to acquire, trading off acquisition cost and predictive performance. A2MT extends a previous task called active feature acquisition to temporal decision making about high-dimensional inputs. Further, we propose a method based on the Perceiver IO architecture to address A2MT in practice. Our agents are able to solve a novel synthetic scenario requiring practically relevant cross-modal reasoning skills. On two large-scale, real-world datasets, Kinetics-700 and AudioSet, our agents successfully learn cost-reactive acquisition behavior. However, an ablation reveals they are unable to learn to learn adaptive acquisition strategies, emphasizing the difficulty of the task even for state-of-the-art models. Applications of A2MT may be impactful in domains like medicine, robotics, or finance, where modalities differ in acquisition cost and informativeness.

Transformer, originally devised for natural language processing, has also attested significant success in computer vision. Thanks to its super expressive power, researchers are investigating ways to deploy transformers to reinforcement learning (RL) and the transformer-based models have manifested their potential in representative RL benchmarks. In this paper, we collect and dissect recent advances on transforming RL by transformer (transformer-based RL or TRL), in order to explore its development trajectory and future trend. We group existing developments in two categories: architecture enhancement and trajectory optimization, and examine the main applications of TRL in robotic manipulation, text-based games, navigation and autonomous driving. For architecture enhancement, these methods consider how to apply the powerful transformer structure to RL problems under the traditional RL framework, which model agents and environments much more precisely than deep RL methods, but they are still limited by the inherent defects of traditional RL algorithms, such as bootstrapping and "deadly triad". For trajectory optimization, these methods treat RL problems as sequence modeling and train a joint state-action model over entire trajectories under the behavior cloning framework, which are able to extract policies from static datasets and fully use the long-sequence modeling capability of the transformer. Given these advancements, extensions and challenges in TRL are reviewed and proposals about future direction are discussed. We hope that this survey can provide a detailed introduction to TRL and motivate future research in this rapidly developing field.

Humans perceive the world by concurrently processing and fusing high-dimensional inputs from multiple modalities such as vision and audio. Machine perception models, in stark contrast, are typically modality-specific and optimised for unimodal benchmarks, and hence late-stage fusion of final representations or predictions from each modality (`late-fusion') is still a dominant paradigm for multimodal video classification. Instead, we introduce a novel transformer based architecture that uses `fusion bottlenecks' for modality fusion at multiple layers. Compared to traditional pairwise self-attention, our model forces information between different modalities to pass through a small number of bottleneck latents, requiring the model to collate and condense the most relevant information in each modality and only share what is necessary. We find that such a strategy improves fusion performance, at the same time reducing computational cost. We conduct thorough ablation studies, and achieve state-of-the-art results on multiple audio-visual classification benchmarks including Audioset, Epic-Kitchens and VGGSound. All code and models will be released.

Adequately assigning credit to actions for future outcomes based on their contributions is a long-standing open challenge in Reinforcement Learning. The assumptions of the most commonly used credit assignment method are disadvantageous in tasks where the effects of decisions are not immediately evident. Furthermore, this method can only evaluate actions that have been selected by the agent, making it highly inefficient. Still, no alternative methods have been widely adopted in the field. Hindsight Credit Assignment is a promising, but still unexplored candidate, which aims to solve the problems of both long-term and counterfactual credit assignment. In this thesis, we empirically investigate Hindsight Credit Assignment to identify its main benefits, and key points to improve. Then, we apply it to factored state representations, and in particular to state representations based on the causal structure of the environment. In this setting, we propose a variant of Hindsight Credit Assignment that effectively exploits a given causal structure. We show that our modification greatly decreases the workload of Hindsight Credit Assignment, making it more efficient and enabling it to outperform the baseline credit assignment method on various tasks. This opens the way to other methods based on given or learned causal structures.

Many real-world problems are inherently multimodal, from the communicative modalities humans use to express social and emotional states to the force, proprioception, and visual sensors ubiquitous on robots. While there has been an explosion of interest in multimodal representation learning, these methods are still largely focused on a small set of modalities, primarily in the language, vision, and audio space. In order to accelerate generalization towards diverse and understudied modalities, this paper studies efficient representation learning for high-modality scenarios. Since adding new models for every new modality or task becomes prohibitively expensive, a critical technical challenge is heterogeneity quantification: how can we measure which modalities encode similar information and interactions in order to permit parameter sharing with previous modalities? We propose two new information-theoretic metrics for heterogeneity quantification: (1) modality heterogeneity studies how similar 2 modalities $\{X_1,X_2\}$ are by measuring how much information can be transferred from $X_1$ to $X_2$, while (2) interaction heterogeneity studies how similarly pairs of modalities $\{X_1,X_2\}, \{X_3,X_4\}$ interact by measuring how much interaction information can be transferred from $\{X_1,X_2\}$ to $\{X_3,X_4\}$. We show the importance of these proposed metrics in high-modality scenarios as a way to automatically prioritize the fusion of modalities that contain unique information or interactions. The result is a single model, HighMMT, that scales up to $10$ modalities and $15$ tasks from $5$ different research areas. Not only does HighMMT outperform prior methods on the tradeoff between performance and efficiency, it also demonstrates a crucial scaling behavior: performance continues to improve with each modality added, and transfers to entirely new modalities and tasks during fine-tuning.

对于那些在线寻求医疗保健建议的人，能够与患者进行自动疾病诊断的基于AI的对话代理是一个可行的选择。该应用需要有效地查询相关疾病症状，以便进行准确的诊断建议。可以将其作为顺序特征（症状）选择和分类的问题进行表述，并为其作为自然解决方案提出了增强学习方法（RL）方法。当特征空间很小时，它们的表现良好，也就是说，症状的数量和可诊断性疾病类别的数量有限，但是它们经常失败的作业，具有大量特征。为了应对这一挑战，我们提出了一个由生成演员网络和诊断评论家网络组成的多模型融合的演员 - 批评者（MMF-AC）RL框架。演员融合了变异自动编码器（VAE），以对特征部分观察结果引起的不确定性进行建模，从而促进进行适当的查询。在评论家网络中，涉及疾病预测的监督诊断模型，以精确估计状态值功能。此外，受鉴别诊断的医学概念的启发，我们结合了生成和诊断模型，以创建一种新颖的奖励成型机制，以解决大型搜索空间中稀疏奖励问题。我们对合成数据集和现实数据集进行了广泛的实验，以进行经验评估。结果表明，我们的方法在诊断准确性和互动效率方面优于最先进的方法，同时更有效地可扩展到大型搜索空间。此外，我们的方法适用于分类和连续功能，使其非常适合在线应用程序。

尽管深度强化学习（RL）最近取得了许多成功，但其方法仍然效率低下，这使得在数据方面解决了昂贵的许多问题。我们的目标是通过利用未标记的数据中的丰富监督信号来进行学习状态表示，以解决这一问题。本文介绍了三种不同的表示算法，可以访问传统RL算法使用的数据源的不同子集使用：（i）GRICA受到独立组件分析（ICA）的启发，并训练深层神经网络以输出统计独立的独立特征。输入。 Grica通过最大程度地减少每个功能与其他功能之间的相互信息来做到这一点。此外，格里卡仅需要未分类的环境状态。 （ii）潜在表示预测（LARP）还需要更多的上下文：除了要求状态作为输入外，它还需要先前的状态和连接它们的动作。该方法通过预测当前状态和行动的环境的下一个状态来学习状态表示。预测器与图形搜索算法一起使用。 （iii）重新培训通过训练深层神经网络来学习国家表示，以学习奖励功能的平滑版本。该表示形式用于预处理输入到深度RL，而奖励预测指标用于奖励成型。此方法仅需要环境中的状态奖励对学习表示表示。我们发现，每种方法都有其优势和缺点，并从我们的实验中得出结论，包括无监督的代表性学习在RL解决问题的管道中可以加快学习的速度。

Deep reinforcement learning is poised to revolutionise the field of AI and represents a step towards building autonomous systems with a higher level understanding of the visual world. Currently, deep learning is enabling reinforcement learning to scale to problems that were previously intractable, such as learning to play video games directly from pixels. Deep reinforcement learning algorithms are also applied to robotics, allowing control policies for robots to be learned directly from camera inputs in the real world. In this survey, we begin with an introduction to the general field of reinforcement learning, then progress to the main streams of value-based and policybased methods. Our survey will cover central algorithms in deep reinforcement learning, including the deep Q-network, trust region policy optimisation, and asynchronous advantage actor-critic. In parallel, we highlight the unique advantages of deep neural networks, focusing on visual understanding via reinforcement learning. To conclude, we describe several current areas of research within the field.

在测试时间缺失模态的多模式数据的学习表示，由于从不同渠道获得的数据的固有异质性，这是一个具有挑战性的问题。为了解决这个问题，我们提出了一种新型的几何多模式对比度（GMC）表示方法，该学习方法由两个主要组成部分组成：i）由特定于模态的基础编码器组成的两级体系结构，允许处理任意数量的模态，以使中间表示形式固定维度和共享投影头，将中间表示形式映射到潜在的表示空间； ii）一种多模式对比损失函数，鼓励学习表示的几何对齐。我们通过实验表明，GMC表示在语义上是丰富的，并实现了最先进的表现，而缺少有关三种不同学习问题的模式信息，包括预测和强化学习任务。

多模式分类是人类以人为本的机器学习中的核心任务。我们观察到信息跨多模式融合在多模式融合之前，信息在偶像中具有高度互补的信息，因此在多模式融合之前可以彻底稀释。为此，我们呈现稀疏的融合变压器（SFT），一种用于现有最先进的方法的变压器的新型多模式融合方法，同时具有大大降低了内存占用和计算成本。我们想法的关键是稀疏池块，可在跨模式建模之前减少单峰令牌集合。评估在多个多模式基准数据集上进行，用于广泛的分类任务。在类似的实验条件下的多个基准上获得最先进的性能，同时报告计算成本和内存要求降低六倍。广泛的消融研究展示了在天真的方法中结合稀疏和多式化学习的好处。这铺平了在低资源设备上实现多模级学习的方式。

通过互动学习复杂的机器人行为需要结构化探索。规划应瞄准与优化长期绩效的潜力的相互作用，同时只减少有利于这一目标的不确定性。本文提出了潜在的乐观价值探索（爱），这一战略在面对不确定的长期奖励面前通过乐观探索能够深入探索。我们将潜在的世界模型与价值函数估计相结合以预测无限地平线返回并通过合并恢复相关的不确定性。然后，该政策培训了上束缚（UCB）目标，以确定和选择最有希望改善长期绩效的交互。我们在连续动作空间中应用了视觉机器人控制任务，并且与最先进的和其他探索目标相比，平均提高了样品效率的平均提高了20％以上。在稀疏和难以探索环境中，我们实现了超过30％的平均改善。

自动驾驶的运动预测是一项艰巨的任务，因为复杂的驾驶场景导致静态和动态输入的异质组合。这是一个开放的问题，如何最好地表示和融合有关道路几何，车道连接，时变的交通信号状态以及动态代理的历史及其相互作用的历史。为了模拟这一不同的输入功能集，许多提出的方法旨在设计具有多种模态模块的同样复杂系统。这导致难以按严格的方式进行扩展，扩展或调整的系统以进行质量和效率。在本文中，我们介绍了Wayformer，这是一个基于注意力的运动架构，用于运动预测，简单而均匀。 Wayformer提供了一个紧凑的模型描述，该描述由基于注意力的场景编码器和解码器组成。在场景编码器中，我们研究了输入方式的早期，晚和等级融合的选择。对于每种融合类型，我们通过分解的注意力或潜在的查询关注来探索策略来折衷效率和质量。我们表明，尽管早期融合的结构简单，但不仅是情感不可知论，而且还取得了最先进的结果。

General perception systems such as Perceivers can process arbitrary modalities in any combination and are able to handle up to a few hundred thousand inputs. They achieve this generality by using exclusively global attention operations. This however hinders them from scaling up to the inputs sizes required to process raw high-resolution images or video. In this paper, we show that some degree of locality can be introduced back into these models, greatly improving their efficiency while preserving their generality. To scale them further, we introduce a self-supervised approach that enables learning dense low-dimensional positional embeddings for very large signals. We call the resulting model a Hierarchical Perceiver (HiP). In sum our contributions are: 1) scaling Perceiver-type models to raw high-resolution images and audio+video, 2) showing the feasibility of learning 1M+ positional embeddings from scratch using masked auto-encoding, 3) demonstrating competitive performance on raw data from ImageNet, AudioSet, PASCAL VOC, ModelNet40 and Kinetics datasets with the same exact, unchanged model and without specialized preprocessing or any tokenization.

现实世界中的数据是高维的：即使在压缩后，书籍，图像或音乐表演也很容易包含数十万个元素。但是，最常用的自回归模型，变压器非常昂贵，以缩放捕获这种远程结构所需的输入和层数。我们开发了感知者AR，这是一种自回归的模态 - 不合骨架构，它使用交叉注意力将远程输入映射到少数潜在的潜在，同时还可以维护端到端的因果关系掩盖。感知器AR可以直接进行十万个令牌，从而实现了实用的长篇小写密度估计，而无需手工制作的稀疏模式或记忆机制。当对图像或音乐进行培训时，感知器AR会生成具有清晰长期连贯性和结构的输出。我们的架构还获得了长期基准测试的最新可能性，包括64 x 64个Imagenet图像和PG-19书籍。

Humans and animals have the ability to continually acquire, fine-tune, and transfer knowledge and skills throughout their lifespan. This ability, referred to as lifelong learning, is mediated by a rich set of neurocognitive mechanisms that together contribute to the development and specialization of our sensorimotor skills as well as to long-term memory consolidation and retrieval. Consequently, lifelong learning capabilities are crucial for computational systems and autonomous agents interacting in the real world and processing continuous streams of information. However, lifelong learning remains a long-standing challenge for machine learning and neural network models since the continual acquisition of incrementally available information from non-stationary data distributions generally leads to catastrophic forgetting or interference. This limitation represents a major drawback for state-of-the-art deep neural network models that typically learn representations from stationary batches of training data, thus without accounting for situations in which information becomes incrementally available over time. In this review, we critically summarize the main challenges linked to lifelong learning for artificial learning systems and compare existing neural network approaches that alleviate, to different extents, catastrophic forgetting. Although significant advances have been made in domain-specific learning with neural networks, extensive research efforts are required for the development of robust lifelong learning on autonomous agents and robots. We discuss well-established and emerging research motivated by lifelong learning factors in biological systems such as structural plasticity, memory replay, curriculum and transfer learning, intrinsic motivation, and multisensory integration.

最近的视听导航工作是无噪音音频环境中的单一静态声音，并努力推广到闻名声音。我们介绍了一种新型动态视听导航基准测试，其中一个体现的AI代理必须在存在分散的人和嘈杂的声音存在下在未映射的环境中捕获移动声源。我们提出了一种依赖于多模态架构的端到端增强学习方法，该方法依赖于融合来自双耳音频信号和空间占用映射的空间视听信息，以编码为我们的新的稳健导航策略进行编码所需的功能复杂的任务设置。我们展示了我们的方法优于当前的最先进状态，以更好地推广到闻名声音以及对嘈杂的3D扫描现实世界数据集副本和TASTPORT3D上的嘈杂情景更好地对嘈杂的情景进行了更好的稳健性，以实现静态和动态的视听导航基准。我们的小型基准将在http://dav-nav.cs.uni-freiburg.de提供。

自动识别面部和声音的明显情绪很难，部分原因是各种不确定性来源，包括输入数据和机器学习框架中使用的标签。本文介绍了一种不确定性感知的视听融合方法，该方法量化了对情绪预测的模态不确定性。为此，我们提出了一个新颖的融合框架，在该框架中，我们首先通过视听时间上下文向量学习潜在分布，然后限制单峰潜在分布的方差向量，以便它们表示每种模式的信息量，以提供W.R.T.情绪识别。特别是，我们对视听潜在分布的方差向量施加了校准和序数排名约束。当经过良好校准时，将模态不确定性得分表明它们的相应预测可能与地面真实标签有多大不同。排名良好的不确定性得分允许在模式中对不同框架进行顺序排名。为了共同施加这两种约束，我们提出了软马克斯分布匹配损失。在分类和回归设置中，我们将不确定性感知的融合模型与标准模型 - 静态融合基线进行了比较。我们对两个情绪识别语料库（AVEC 2019 CES和IEMOCAP）的评估表明，视听情绪识别可以从良好的和良好的潜在不确定性度量中受益匪浅。

大规模未标记数据集的预培训显示了计算机视觉和自然语言处理领域的令人印象深刻的性能改进。鉴于大规模教学视频数据集的出现，预训练视频编码器的常见策略是使用随附的语音作为弱监管。但是，由于演讲用于监督预培训，视频编码器从未见过，这不会学会处理该模态。我们解决了当前预训练方法的这种缺点，这未能利用口语语言中的丰富的线索。我们的提议是使用所有可用的视频模型作为监督，即外观，声音和转录语音预先列车。我们在输入中掩盖了整个模态并使用其他两个模态预测它。这鼓励每个码头与其他方式合作，我们的视频编码器学会处理外观和音频以及语音。我们展示了我们在How2R，YouScook2和浓缩电影数据集上视频检索的“模态屏蔽”预培训方法的卓越性能。

拥有丰富的多模式内在语言是人类智力的重要组成部分，它可以实现多种必要的核心认知功能，例如多模式预测，翻译和生成。在有意识的图灵机（CTM）的基础上，这是Blum and Blum提出的意识模型（2021），我们描述了一种称为Brainish的多模式的Desiderata，包括单词，图像，音频和感觉，结合了CTM的表示形式处理器用来相互通信。我们在通过多模式人工智能的镜头进行操作之前定义了大脑的语法和语义，这是一个充满活力的研究区域，研究了处理和关联异质信号信息所需的计算工具。我们学习的一般框架涉及设计（1）单峰编码器以细分并表示非模态数据，（2）协调的表示空间，该空间将和编写单峰特征与多模式输入的整体含义相关联，以及（3）解码器以映射多模式表示形式。进入预测（用于融合）或原始数据（用于翻译或生成）。通过讨论为了在CTM中实现意识以及实施简单版本的脑部和评估其在几个现实世界图像，文本和文本和检索任务上展示智能的能力，通过讨论对沟通和协调的脑力至关重要音频数据集，我们认为这种内在语言对于机器智力和意识模型的进步将很重要。

Concept bottleneck models (CBMs) (Koh et al. 2020) are interpretable neural networks that first predict labels for human-interpretable concepts relevant to the prediction task, and then predict the final label based on the concept label predictions.We extend CBMs to interactive prediction settings where the model can query a human collaborator for the label to some concepts. We develop an interaction policy that, at prediction time, chooses which concepts to request a label for so as to maximally improve the final prediction. We demonstrate thata simple policy combining concept prediction uncertainty and influence of the concept on the final prediction achieves strong performance and outperforms a static approach proposed in Koh et al. (2020) as well as active feature acquisition methods proposed in the literature. We show that the interactiveCBM can achieve accuracy gains of 5-10% with only 5 interactions over competitive baselines on the Caltech-UCSDBirds, CheXpert and OAI datasets.