本文研究了一种使用背景计划的新方法,用于基于模型的增强学习:混合(近似)动态编程更新和无模型更新,类似于DYNA体系结构。通过学习模型的背景计划通常比无模型替代方案(例如Double DQN)差,尽管前者使用了更多的内存和计算。基本问题是,学到的模型可能是不准确的,并且经常会产生无效的状态,尤其是在迭代许多步骤时。在本文中,我们通过将背景规划限制为一组(抽象)子目标并仅学习本地,子观念模型来避免这种限制。这种目标空间计划(GSP)方法更有效地是在计算上,自然地纳入了时间抽象,以进行更快的长胜压计划,并避免完全学习过渡动态。我们表明,在各种情况下,我们的GSP算法比双DQN基线要快得多。
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通用形态(UNIMORPH)项目是一项合作的努力,可为数百种世界语言实例化覆盖范围的标准化形态拐角。该项目包括两个主要的推力:一种无独立的特征架构,用于丰富的形态注释,并以各种语言意识到该模式的各种语言的带注释数据的类型级别资源。本文介绍了过去几年对几个方面的扩张和改进(自McCarthy等人(2020年)以来)。众多语言学家的合作努力增加了67种新语言,其中包括30种濒危语言。我们已经对提取管道进行了一些改进,以解决一些问题,例如缺少性别和马克龙信息。我们还修改了模式,使用了形态学现象所需的层次结构,例如多肢体协议和案例堆叠,同时添加了一些缺失的形态特征,以使模式更具包容性。鉴于上一个UniMorph版本,我们还通过16种语言的词素分割增强了数据库。最后,这个新版本通过通过代表来自metphynet的派生过程的实例丰富数据和注释模式来推动将衍生物形态纳入UniMorph中。
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在本文中,我们为Pavlovian信号传达的多方面的研究 - 一个过程中学到的一个过程,一个代理商通过另一个代理商通知决策的时间扩展预测。信令紧密连接到时间和时间。在生成和接收信号的服务中,已知人类和其他动物代表时间,确定自过去事件以来的时间,预测到未来刺激的时间,并且都识别和生成展开时间的模式。我们调查通过引入部分可观察到的决策域来对学习代理之间的影响和信令在我们称之为霜冻空心的情况下如何影响学习代理之间的影响和信令。在该域中,预测学习代理和加强学习代理被耦合到两部分决策系统,该系统可以在避免时间条件危险时获取稀疏奖励。我们评估了两个域变型:机器代理在七态线性步行中交互,以及虚拟现实环境中的人机交互。我们的结果展示了帕夫洛维亚信号传导的学习速度,对药剂 - 代理协调具有不同时间表示(并且不)的影响,以及颞次锯齿对药剂和人毒剂相互作用的影响方式不同。作为主要贡献,我们将Pavlovian信号传导为固定信号范例与两个代理之间完全自适应通信学习之间的天然桥梁。我们进一步展示了如何从固定的信令过程计算地构建该自适应信令处理,其特征在于,通过快速的连续预测学习和对接收信号的性质的最小限制。因此,我们的结果表明了加固学习代理之间的沟通学习的可行建设者的途径。
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人工智能系统越来越涉及持续学习,以实现在系统培训期间不遇到的一般情况下的灵活性。与自治系统的人类互动广泛研究,但在系统积极学习的同时,研究发生了迄今为止发生的互动,并且可以在几分钟内明显改变其行为。在这项试验研究中,我们调查如何在代理商发展能力时如何发展人类和不断学习的预测代理人之间的互动。此外,我们可以比较两个不同的代理架构来评估代理设计中的代表性选择如何影响人工代理交互。我们开发虚拟现实环境和基于时间的预测任务,其中从增强学习(RL)算法增强人类预测中学到的预测。我们评估参与者在此任务中的性能和行为如何在代理类型中不同,使用定量和定性分析。我们的研究结果表明,系统的人类信任可能受到与代理人的早期互动的影响,并且反过来的信任会影响战略行为,但试点研究的限制排除了任何结论的声明。我们将信任作为互动的关键特征,以考虑基于RL的技术在考虑基于RL的技术时,并对这项研究进行了几项建议,以准备更大规模的调查。本文的视频摘要可以在https://youtu.be/ovyjdnbqtwq找到。
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在本文中,我们基于定向图的语义表示形式主义,并在多种和量化的语义中探讨其语言充足性和解释益处。我们的图表语言仅使用Monadic二阶变量涵盖自然语言语义的必要性。我们在图形遍历方面定义其模型理论解释,其中变量的相对范围从其估值顺序产生。我们提出了一种基于统一的机制,用于在简单的语法语义界面构建语义图,其中通过在语义与语法分布之间建立部分确定性关系来实现作为话语引用的分区函数的语法。这种机制是自动的,以促进未来的探索。本图形式主义应用于量化的预测,跨分类结合和量化表达式的语言问题,包括无限的特殊范围行为。
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本文引入了一种新颖的可解释的AI方法,称为清晰图像。清晰的图像是基于以下观点:令人满意的解释应该是对比,反事实和可衡量的。清晰的图像通过将图像与通过对抗性学习自动生成的相应图像进行对比,从而解释了图像的分类概率。这使得忠实地确定每个细分市场的重要性的显着细分和扰动。清晰的图像已成功地应用于医学成像案例研究中,在该案例研究中,使用新颖的指向游戏指标,它的表现平均比Grad-CAM和Lime的方法平均27%。清晰的图像在识别“因果过度确定”的情况下奇特,其中图像中有多个贴片,其中任何一个本身就足以使分类概率接近一个。
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Although many studies have successfully applied transfer learning to medical image segmentation, very few of them have investigated the selection strategy when multiple source tasks are available for transfer. In this paper, we propose a prior knowledge guided and transferability based framework to select the best source tasks among a collection of brain image segmentation tasks, to improve the transfer learning performance on the given target task. The framework consists of modality analysis, RoI (region of interest) analysis, and transferability estimation, such that the source task selection can be refined step by step. Specifically, we adapt the state-of-the-art analytical transferability estimation metrics to medical image segmentation tasks and further show that their performance can be significantly boosted by filtering candidate source tasks based on modality and RoI characteristics. Our experiments on brain matter, brain tumor, and white matter hyperintensities segmentation datasets reveal that transferring from different tasks under the same modality is often more successful than transferring from the same task under different modalities. Furthermore, within the same modality, transferring from the source task that has stronger RoI shape similarity with the target task can significantly improve the final transfer performance. And such similarity can be captured using the Structural Similarity index in the label space.
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Directed information (DI) is a fundamental measure for the study and analysis of sequential stochastic models. In particular, when optimized over input distributions it characterizes the capacity of general communication channels. However, analytic computation of DI is typically intractable and existing optimization techniques over discrete input alphabets require knowledge of the channel model, which renders them inapplicable when only samples are available. To overcome these limitations, we propose a novel estimation-optimization framework for DI over discrete input spaces. We formulate DI optimization as a Markov decision process and leverage reinforcement learning techniques to optimize a deep generative model of the input process probability mass function (PMF). Combining this optimizer with the recently developed DI neural estimator, we obtain an end-to-end estimation-optimization algorithm which is applied to estimating the (feedforward and feedback) capacity of various discrete channels with memory. Furthermore, we demonstrate how to use the optimized PMF model to (i) obtain theoretical bounds on the feedback capacity of unifilar finite-state channels; and (ii) perform probabilistic shaping of constellations in the peak power-constrained additive white Gaussian noise channel.
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Feature selection helps reduce data acquisition costs in ML, but the standard approach is to train models with static feature subsets. Here, we consider the dynamic feature selection (DFS) problem where a model sequentially queries features based on the presently available information. DFS is often addressed with reinforcement learning (RL), but we explore a simpler approach of greedily selecting features based on their conditional mutual information. This method is theoretically appealing but requires oracle access to the data distribution, so we develop a learning approach based on amortized optimization. The proposed method is shown to recover the greedy policy when trained to optimality and outperforms numerous existing feature selection methods in our experiments, thus validating it as a simple but powerful approach for this problem.
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While the brain connectivity network can inform the understanding and diagnosis of developmental dyslexia, its cause-effect relationships have not yet enough been examined. Employing electroencephalography signals and band-limited white noise stimulus at 4.8 Hz (prosodic-syllabic frequency), we measure the phase Granger causalities among channels to identify differences between dyslexic learners and controls, thereby proposing a method to calculate directional connectivity. As causal relationships run in both directions, we explore three scenarios, namely channels' activity as sources, as sinks, and in total. Our proposed method can be used for both classification and exploratory analysis. In all scenarios, we find confirmation of the established right-lateralized Theta sampling network anomaly, in line with the temporal sampling framework's assumption of oscillatory differences in the Theta and Gamma bands. Further, we show that this anomaly primarily occurs in the causal relationships of channels acting as sinks, where it is significantly more pronounced than when only total activity is observed. In the sink scenario, our classifier obtains 0.84 and 0.88 accuracy and 0.87 and 0.93 AUC for the Theta and Gamma bands, respectively.
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