最近，致力于通过现代机器学习方法预测脑部疾病的最新神经影像学研究通常包括单一模态并依靠监督的过度参数化模型。但是，单一模态仅提供了高度复杂的大脑的有限视图。至关重要的是，临床环境中的有监督模型缺乏用于培训的准确诊断标签。粗标签不会捕获脑疾病表型的长尾谱，这导致模型的普遍性丧失，从而使它们在诊断环境中的有用程度降低。这项工作提出了一个新型的多尺度协调框架，用于从多模式神经影像数据中学习多个表示。我们提出了一般的归纳偏见分类法，以捕获多模式自学融合中的独特和联合信息。分类法构成了一个无解码器模型的家族，具有降低的计算复杂性，并捕获多模式输入的本地和全局表示之间的多尺度关系。我们使用各种阿尔茨海默氏病表型中使用功能和结构磁共振成像（MRI）数据对分类法进行了全面评估，并表明自我监督模型揭示了与疾病相关的大脑区域和多模态链接，而无需在预先访问PRE-PRE-the PRE-the PRE-the PRE-the PRE-PRECTEN NICKES NOCKER NOCKER NOCKER NOCKER NOCKER NOCE访问。训练。拟议的多模式自学学习的学习能够表现出两种模式的分类表现。伴随的丰富而灵活的无监督的深度学习框架捕获了复杂的多模式关系，并提供了符合或超过更狭窄的监督分类分析的预测性能。我们提供了详尽的定量证据，表明该框架如何显着提高我们对复杂脑部疾病中缺失的联系的搜索。

对比度学习依赖于假设正对包含相关视图，例如，视频的图像或视频的共同发生的多峰信号，其共享关于实例的某些基础信息。但如果违反了这个假设怎么办？该文献表明，对比学学习在存在嘈杂的视图中产生次优表示，例如，没有明显共享信息的假正对。在这项工作中，我们提出了一种新的对比损失函数，这是对嘈杂的观点的强大。我们通过显示嘈杂二进制分类的强大对称损失的连接提供严格的理论理由，并通过基于Wassersein距离测量来建立新的对比界限进行新的对比。拟议的损失是完全的方式无话无双，并且对Innoconce损失的更换简单的替代品，这使得适用于现有的对比框架。我们表明，我们的方法提供了在展示各种现实世界噪声模式的图像，视频和图形对比学习基准上的一致性改进。

We propose an approach to self-supervised representation learning based on maximizing mutual information between features extracted from multiple views of a shared context. For example, one could produce multiple views of a local spatiotemporal context by observing it from different locations (e.g., camera positions within a scene), and via different modalities (e.g., tactile, auditory, or visual). Or, an ImageNet image could provide a context from which one produces multiple views by repeatedly applying data augmentation. Maximizing mutual information between features extracted from these views requires capturing information about high-level factors whose influence spans multiple views -e.g., presence of certain objects or occurrence of certain events. Following our proposed approach, we develop a model which learns image representations that significantly outperform prior methods on the tasks we consider. Most notably, using self-supervised learning, our model learns representations which achieve 68.1% accuracy on Im-ageNet using standard linear evaluation. This beats prior results by over 12% and concurrent results by 7%. When we extend our model to use mixture-based representations, segmentation behaviour emerges as a natural side-effect. Our code is available online: https://github.com/Philip-Bachman/amdim-public.

We present Deep Graph Infomax (DGI), a general approach for learning node representations within graph-structured data in an unsupervised manner. DGI relies on maximizing mutual information between patch representations and corresponding high-level summaries of graphs-both derived using established graph convolutional network architectures. The learnt patch representations summarize subgraphs centered around nodes of interest, and can thus be reused for downstream node-wise learning tasks. In contrast to most prior approaches to unsupervised learning with GCNs, DGI does not rely on random walk objectives, and is readily applicable to both transductive and inductive learning setups. We demonstrate competitive performance on a variety of node classification benchmarks, which at times even exceeds the performance of supervised learning.

This work investigates unsupervised learning of representations by maximizing mutual information between an input and the output of a deep neural network encoder. Importantly, we show that structure matters: incorporating knowledge about locality in the input into the objective can significantly improve a representation's suitability for downstream tasks. We further control characteristics of the representation by matching to a prior distribution adversarially. Our method, which we call Deep InfoMax (DIM), outperforms a number of popular unsupervised learning methods and compares favorably with fully-supervised learning on several classification tasks in with some standard architectures. DIM opens new avenues for unsupervised learning of representations and is an important step towards flexible formulations of representation learning objectives for specific end-goals.

直觉上，人们所期望的训练的神经网络对测试样本进行相关预测与如何密集的该样本是由表示太空中看到的训练样本包围的准确性。在这项工作中，我们提供了理论依据和支持这一假设的实验。我们提出了一种误差函数为分段线性，需要一个局部区域中的网络的输入空间，并输出平滑经验训练误差，这是一个从平均通过网络表示距离加权其他区域经验训练误差的神经网络。甲绑定在预期平滑误差为每个区域尺度成反比地表示空间训练样本密度。根据经验，我们验证这个边界是网络的预测上测试样品不准确的一个强有力的预测。对于看不见的测试设备，包括那些外的分布样本，通过结合当地区域的错误排名测试样品和最高界限丢弃样品提高了20％的绝对数字来看，对图像分类数据集的预测精度。

The recent increase in public and academic interest in preserving biodiversity has led to the growth of the field of conservation technology. This field involves designing and constructing tools that utilize technology to aid in the conservation of wildlife. In this article, we will use case studies to demonstrate the importance of designing conservation tools with human-wildlife interaction in mind and provide a framework for creating successful tools. These case studies include a range of complexities, from simple cat collars to machine learning and game theory methodologies. Our goal is to introduce and inform current and future researchers in the field of conservation technology and provide references for educating the next generation of conservation technologists. Conservation technology not only has the potential to benefit biodiversity but also has broader impacts on fields such as sustainability and environmental protection. By using innovative technologies to address conservation challenges, we can find more effective and efficient solutions to protect and preserve our planet's resources.

A Digital Twin (DT) is a simulation of a physical system that provides information to make decisions that add economic, social or commercial value. The behaviour of a physical system changes over time, a DT must therefore be continually updated with data from the physical systems to reflect its changing behaviour. For resource-constrained systems, updating a DT is non-trivial because of challenges such as on-board learning and the off-board data transfer. This paper presents a framework for updating data-driven DTs of resource-constrained systems geared towards system health monitoring. The proposed solution consists of: (1) an on-board system running a light-weight DT allowing the prioritisation and parsimonious transfer of data generated by the physical system; and (2) off-board robust updating of the DT and detection of anomalous behaviours. Two case studies are considered using a production gas turbine engine system to demonstrate the digital representation accuracy for real-world, time-varying physical systems.

We consider infinite horizon Markov decision processes (MDPs) with fast-slow structure, meaning that certain parts of the state space move "fast" (and in a sense, are more influential) while other parts transition more "slowly." Such structure is common in real-world problems where sequential decisions need to be made at high frequencies, yet information that varies at a slower timescale also influences the optimal policy. Examples include: (1) service allocation for a multi-class queue with (slowly varying) stochastic costs, (2) a restless multi-armed bandit with an environmental state, and (3) energy demand response, where both day-ahead and real-time prices play a role in the firm's revenue. Models that fully capture these problems often result in MDPs with large state spaces and large effective time horizons (due to frequent decisions), rendering them computationally intractable. We propose an approximate dynamic programming algorithmic framework based on the idea of "freezing" the slow states, solving a set of simpler finite-horizon MDPs (the lower-level MDPs), and applying value iteration (VI) to an auxiliary MDP that transitions on a slower timescale (the upper-level MDP). We also extend the technique to a function approximation setting, where a feature-based linear architecture is used. On the theoretical side, we analyze the regret incurred by each variant of our frozen-state approach. Finally, we give empirical evidence that the frozen-state approach generates effective policies using just a fraction of the computational cost, while illustrating that simply omitting slow states from the decision modeling is often not a viable heuristic.

While the capabilities of autonomous systems have been steadily improving in recent years, these systems still struggle to rapidly explore previously unknown environments without the aid of GPS-assisted navigation. The DARPA Subterranean (SubT) Challenge aimed to fast track the development of autonomous exploration systems by evaluating their performance in real-world underground search-and-rescue scenarios. Subterranean environments present a plethora of challenges for robotic systems, such as limited communications, complex topology, visually-degraded sensing, and harsh terrain. The presented solution enables long-term autonomy with minimal human supervision by combining a powerful and independent single-agent autonomy stack, with higher level mission management operating over a flexible mesh network. The autonomy suite deployed on quadruped and wheeled robots was fully independent, freeing the human supervision to loosely supervise the mission and make high-impact strategic decisions. We also discuss lessons learned from fielding our system at the SubT Final Event, relating to vehicle versatility, system adaptability, and re-configurable communications.