牙齿疾病是最常见的慢性疾病之一，尽管可以预防。但是，关于最佳口腔卫生实践的专业建议通常被患者遗忘或放弃。因此，患者可能会受益于及时和个性化的鼓励来进行口腔自我保健行为。在本文中，我们开发了一种在线增强学习（RL）算法，用于优化基于移动的提示以鼓励口腔卫生行为的交付。开发这种算法的主要挑战之一是确保算法考虑当前行动对未来行动有效性（即延迟效应）的影响，尤其是当使算法变得稳定，自动运行时，尤其是当该算法变得简单时在受约束的现实世界中（即高度嘈杂，稀疏的数据）中。我们通过设计质量奖励来应对这一挑战，从而最大程度地提高所需的健康结果（即高质量的刷牙），同时最大程度地减少用户负担。我们还强调了一个程序，可以通过构建模拟环境测试床并使用测试床评估候选人来优化奖励的超参数。本文讨论的RL算法将用于Oralytics，这是一种口头自我护理应用程序，提供行为策略，以促进患者参与口腔卫生实践。

在线增强学习（RL）算法越来越多地用于个性化移动健康和在线教育领域的数字干预措施。在这些设置中设计和测试RL算法方面的常见挑战包括确保RL算法在实时约束下可以稳定学习和运行，并考虑了环境的复杂性，例如，缺乏用于用户动力学的准确机械模型。为了指导人们如何应对这些挑战，我们将PC（可预测性，可计算性，稳定性）框架扩展到了一个数据科学框架，该框架结合了监督学习中的机器学习和统计数据的最佳实践（Yu and Kumbier，2020年），用于数字干预设置的RL算法。此外，我们提供有关如何设计仿真环境的准则，这是使用PCS框架评估RL候选算法的关键工具。我们说明了使用PCS框架来设计Oralytics的RL算法，这是一项移动健康研究，旨在通过个性化的干预消息来改善用户的牙刷行为。 Oralytics将于2022年底进入该领域。

强盗算法越来越多地用于现实世界的连续决策问题。与之相关的是能够使用所产生的数据集来支持科学问题的增加，如：一种类型的广告导致更多购买？哪些背景是移动健康干预有效？然而，当与带有强盗算法收集的数据一起使用时，经典统计方法无法提供有效的置信区间。最近已经开发了用于简单模型的替代方法（例如，手段的比较）。然而，使用使用（上下文）强盗算法收集的数据的更复杂模型，缺乏对统计推断进行统计推理的一般方法;例如，当前方法不能用于逻辑回归模型中的参数的有效推断，以获得二进制奖励。在这项工作中，我们开发理论证明使用M估算器的使用 - 这包括基于经验风险最小化的估计，以及最大可能性 - 与自适应算法收集的数据，包括（上下文）强盗算法。具体地，我们表明，用特定自适应重量修改的M估算器可用于构建用于各种推理目标的渐近有效的置信区。

The lack of standardization is a prominent issue in magnetic resonance (MR) imaging. This often causes undesired contrast variations due to differences in hardware and acquisition parameters. In recent years, MR harmonization using image synthesis with disentanglement has been proposed to compensate for the undesired contrast variations. Despite the success of existing methods, we argue that three major improvements can be made. First, most existing methods are built upon the assumption that multi-contrast MR images of the same subject share the same anatomy. This assumption is questionable since different MR contrasts are specialized to highlight different anatomical features. Second, these methods often require a fixed set of MR contrasts for training (e.g., both Tw-weighted and T2-weighted images must be available), which limits their applicability. Third, existing methods generally are sensitive to imaging artifacts. In this paper, we present a novel approach, Harmonization with Attention-based Contrast, Anatomy, and Artifact Awareness (HACA3), to address these three issues. We first propose an anatomy fusion module that enables HACA3 to respect the anatomical differences between MR contrasts. HACA3 is also robust to imaging artifacts and can be trained and applied to any set of MR contrasts. Experiments show that HACA3 achieves state-of-the-art performance under multiple image quality metrics. We also demonstrate the applicability of HACA3 on downstream tasks with diverse MR datasets acquired from 21 sites with different field strengths, scanner platforms, and acquisition protocols.

Neural networks have revolutionized the area of artificial intelligence and introduced transformative applications to almost every scientific field and industry. However, this success comes at a great price; the energy requirements for training advanced models are unsustainable. One promising way to address this pressing issue is by developing low-energy neuromorphic hardware that directly supports the algorithm's requirements. The intrinsic non-volatility, non-linearity, and memory of spintronic devices make them appealing candidates for neuromorphic devices. Here we focus on the reservoir computing paradigm, a recurrent network with a simple training algorithm suitable for computation with spintronic devices since they can provide the properties of non-linearity and memory. We review technologies and methods for developing neuromorphic spintronic devices and conclude with critical open issues to address before such devices become widely used.

In the contemporary media landscape, with the vast and diverse supply of news, it is increasingly challenging to study such an enormous amount of items without a standardized framework. Although attempts have been made to organize and compare news items on the basis of news values, news genres receive little attention, especially the genres in a news consumer's perception. Yet, perceived news genres serve as an essential component in exploring how news has developed, as well as a precondition for understanding media effects. We approach this concept by conceptualizing and operationalizing a non-discrete framework for mapping news items in terms of genre cues. As a starting point, we propose a preliminary set of dimensions consisting of "factuality" and "formality". To automatically analyze a large amount of news items, we deliver two computational models for predicting news sentences in terms of the said two dimensions. Such predictions could then be used for locating news items within our framework. This proposed approach that positions news items upon a multidimensional grid helps in deepening our insight into the evolving nature of news genres.

Mobile health (mHealth) technologies empower patients to adopt/maintain healthy behaviors in their daily lives, by providing interventions (e.g. push notifications) tailored to the user's needs. In these settings, without intervention, human decision making may be impaired (e.g. valuing near term pleasure over own long term goals). In this work, we formalize this relationship with a framework in which the user optimizes a (potentially impaired) Markov Decision Process (MDP) and the mHealth agent intervenes on the user's MDP parameters. We show that different types of impairments imply different types of optimal intervention. We also provide analytical and empirical explorations of these differences.

Interpretability is a pressing issue for machine learning. Common approaches to interpretable machine learning constrain interactions between features of the input, rendering the effects of those features on a model's output comprehensible but at the expense of model complexity. We approach interpretability from a new angle: constrain the information about the features without restricting the complexity of the model. Borrowing from information theory, we use the Distributed Information Bottleneck to find optimal compressions of each feature that maximally preserve information about the output. The learned information allocation, by feature and by feature value, provides rich opportunities for interpretation, particularly in problems with many features and complex feature interactions. The central object of analysis is not a single trained model, but rather a spectrum of models serving as approximations that leverage variable amounts of information about the inputs. Information is allocated to features by their relevance to the output, thereby solving the problem of feature selection by constructing a learned continuum of feature inclusion-to-exclusion. The optimal compression of each feature -- at every stage of approximation -- allows fine-grained inspection of the distinctions among feature values that are most impactful for prediction. We develop a framework for extracting insight from the spectrum of approximate models and demonstrate its utility on a range of tabular datasets.

In this technical note, we introduce an improved variant of nearest neighbors for counterfactual inference in panel data settings where multiple units are assigned multiple treatments over multiple time points, each sampled with constant probabilities. We call this estimator a doubly robust nearest neighbor estimator and provide a high probability non-asymptotic error bound for the mean parameter corresponding to each unit at each time. Our guarantee shows that the doubly robust estimator provides a (near-)quadratic improvement in the error compared to nearest neighbor estimators analyzed in prior work for these settings.

促使模型表现出令人印象深刻的几次学习能力。在测试时间与单个模型或多个模型的组成一起重复相互作用，进一步扩展了功能。这些组成是概率模型，可以用具有随机变量的图形模型的语言表示，其值是复杂的数据类型，例如字符串。具有控制流和动态结构的情况需要概率编程的技术，这些技术允许以统一语言实施不同的模型结构和推理策略。我们从这个角度正式化了几种现有技术，包括刮擦板 /思想链，验证者，星星，选择 - 推动和工具使用。我们将结果程序称为语言模型级联。