Accent plays a significant role in speech communication, influencing understanding capabilities and also conveying a person's identity. This paper introduces a novel and efficient framework for accented Text-to-Speech (TTS) synthesis based on a Conditional Variational Autoencoder. It has the ability to synthesize a selected speaker's speech that is converted to any desired target accent. Our thorough experiments validate the effectiveness of our proposed framework using both objective and subjective evaluations. The results also show remarkable performance in terms of the ability to manipulate accents in the synthesized speech and provide a promising avenue for future accented TTS research.

With a few exceptions, work in offline reinforcement learning (RL) has so far assumed that there is no confounding. In a classical regression setting, confounders introduce omitted variable bias and inhibit the identification of causal effects. In offline RL, they prevent the identification of a policy's value, and therefore make it impossible to perform policy improvement. Using conventional methods in offline RL in the presence of confounding can therefore not only lead to poor decisions and poor policies, but can also have disastrous effects in applications such as healthcare and education. We provide approaches for both off-policy evaluation (OPE) and local policy optimization in the settings of i.i.d. and global confounders. Theoretical and empirical results confirm the validity and viability of these methods.

We consider the stochastic linear contextual bandit problem with high-dimensional features. We analyze the Thompson sampling (TS) algorithm, using special classes of sparsity-inducing priors (e.g. spike-and-slab) to model the unknown parameter, and provide a nearly optimal upper bound on the expected cumulative regret. To the best of our knowledge, this is the first work that provides theoretical guarantees of Thompson sampling in high dimensional and sparse contextual bandits. For faster computation, we use spike-and-slab prior to model the unknown parameter and variational inference instead of MCMC to approximate the posterior distribution. Extensive simulations demonstrate improved performance of our proposed algorithm over existing ones.

Recently, Robey et al. propose a notion of probabilistic robustness, which, at a high-level, requires a classifier to be robust to most but not all perturbations. They show that for certain hypothesis classes where proper learning under worst-case robustness is \textit{not} possible, proper learning under probabilistic robustness \textit{is} possible with sample complexity exponentially smaller than in the worst-case robustness setting. This motivates the question of whether proper learning under probabilistic robustness is always possible. In this paper, we show that this is \textit{not} the case. We exhibit examples of hypothesis classes $\mathcal{H}$ with finite VC dimension that are \textit{not} probabilistically robustly PAC learnable with \textit{any} proper learning rule. However, if we compare the output of the learner to the best hypothesis for a slightly \textit{stronger} level of probabilistic robustness, we show that not only is proper learning \textit{always} possible, but it is possible via empirical risk minimization.

Graph neural networks (GNNs) find applications in various domains such as computational biology, natural language processing, and computer security. Owing to their popularity, there is an increasing need to explain GNN predictions since GNNs are black-box machine learning models. One way to address this is counterfactual reasoning where the objective is to change the GNN prediction by minimal changes in the input graph. Existing methods for counterfactual explanation of GNNs are limited to instance-specific local reasoning. This approach has two major limitations of not being able to offer global recourse policies and overloading human cognitive ability with too much information. In this work, we study the global explainability of GNNs through global counterfactual reasoning. Specifically, we want to find a small set of representative counterfactual graphs that explains all input graphs. Towards this goal, we propose GCFExplainer, a novel algorithm powered by vertex-reinforced random walks on an edit map of graphs with a greedy summary. Extensive experiments on real graph datasets show that the global explanation from GCFExplainer provides important high-level insights of the model behavior and achieves a 46.9% gain in recourse coverage and a 9.5% reduction in recourse cost compared to the state-of-the-art local counterfactual explainers.

In this paper, we study a sequential decision-making problem, called Adaptive Sampling for Discovery (ASD). Starting with a large unlabeled dataset, algorithms for ASD adaptively label the points with the goal to maximize the sum of responses. This problem has wide applications to real-world discovery problems, for example drug discovery with the help of machine learning models. ASD algorithms face the well-known exploration-exploitation dilemma. The algorithm needs to choose points that yield information to improve model estimates but it also needs to exploit the model. We rigorously formulate the problem and propose a general information-directed sampling (IDS) algorithm. We provide theoretical guarantees for the performance of IDS in linear, graph and low-rank models. The benefits of IDS are shown in both simulation experiments and real-data experiments for discovering chemical reaction conditions.

我们提出了一种非平稳核土匪的算法，该算法不需要事先了解非平稳性程度。该算法遵循通过解决平衡探索和剥削的优化问题获得的随机策略。当检测到奖励函数的更改时，它可以通过重新启动来适应非平稳性。我们的算法比以前在非平稳内核强盗设置上的工作更加动态遗憾。此外，当通过使用线性内核应用于非平稳线性匪徒设置时，我们的算法几乎是最小的最佳选择，可以解决非平稳的线性匪徒文献中的空旷问题。我们将算法扩展到使用神经网络，以动态调整特征映射到观察到的数据。我们证明了使用神经切线内核理论的延伸的动态遗憾。我们从经验上证明，我们的算法和扩展可以适应不同程度的非平稳性。

在大脑中找到适当的动态活动的适当表示对于许多下游应用至关重要。由于其高度动态的性质，暂时平均fMRI（功能磁共振成像）只能提供狭窄的脑活动视图。以前的作品缺乏学习和解释大脑体系结构中潜在动态的能力。本文构建了一个有效的图形神经网络模型，该模型均包含了从DWI（扩散加权成像）获得的区域映射的fMRI序列和结构连接性作为输入。我们通过学习样品水平的自适应邻接矩阵并进行新型多分辨率内群平滑来发现潜在大脑动力学的良好表示。我们还将输入归因于具有集成梯度的输入，这使我们能够针对每个任务推断（1）高度涉及的大脑连接和子网络，（2）成像序列的时间键帧，这些成像序列表征了任务，以及（3）歧视单个主体的子网络。这种识别特征在异质任务和个人中表征信号状态的关键子网的能力对神经科学和其他科学领域至关重要。广泛的实验和消融研究表明，我们提出的方法在空间 - 周期性图信号建模中的优越性和效率，具有对脑动力学的深刻解释。

AI和人类为团体审议带来了互补技能。在审议包括风险要素和评估人和AI代理商的能力的探索开采过程中，建模本集团决策尤其挑战。为了调查这个问题，我们向一系列智力展示了一系列的知识问题，通过不完美的AI代理商提供了一系列的人群。集团的目标是评估本集团成员及其可用AI代理商的相对专业知识，评估与不同行动相关的风险，并通过达成共识来最大限度地提高整体奖励。我们在这种不确定的情况下提出和经验验证了人类队决策的模型，并显示了前景理论，影响动态和贝叶斯学习的社会认知构建在预测人AI群体行为中的价值。

医学图像分析模型的可解释性被认为是一个关键的研究领域。我们使用来自五个放射科医生的眼睛跟踪数据的数据集，比较可解释性方法的输出，而是代表放射科医学家所在的热量。我们对从文献中选择的两种方法产生的显着图进行了类别的分析：Grad-Cam和来自注意门控模型的注意力映射。为了比较，我们使用随机测量标准，避免从固定位置偏差。我们在一个混洗型度量中实现了与Interobserver基线相当的分数，突出了来自Grad-Cam的显着图的潜力，以模仿放射科学家在图像上的注意。我们还将数据集分为子集以评估哪种情况相似度更高。