数据是现代机器学习的关键组成部分，但是评估数据标签质量的统计数据在文献中仍然很少。在这里，我们介绍了Dipietro-Hazari Kappa，这是一种新颖的统计指标，用于评估人类注释中建议的数据集标签的质量。Dipietro-Hazari Kappa植根于经典Fleiss的Kappa衡量通道互通的协议量度，量化了在随机机会上获得的经验注释协议差异。在转向我们对Dipietro-Hazari Kappa的推导之前，我们对Fleiss的Kappa进行了彻底的理论检查。最后，我们以矩阵公式和一组程序指令进行结论，以方便计算实现。

自杀是主要的公共卫生危机。每年有超过20,000,000多次自杀企图，对自杀意图的早期发现有可能挽救数十万生命。传统的心理健康筛查方法是耗时的，昂贵的，而且弱势群体通常无法获得；使用机器学习对自杀意图的在线检测提供了可行的替代方法。在这里，我们介绍了迄今为止最大的非关键字生成的自杀语料库Robin，包括超过110万个在线论坛发布。除了其前所未有的规模外，罗宾还专门构建了各种自杀文本，例如自杀丧亲和轻率的参考文献，更好地促进了对罗宾进行培训的模型，以学习表达自杀构思的文本细微差别。实验结果通过传统方法（例如逻辑回归（F1 = 0.85））以及大规模的预训练的语言模型（例如BERT）（F1 = 0.92），实现了自杀文本分类的最新性能。 。最后，我们公开发布Robin数据集作为机器学习资源，有可能推动下一代自杀情绪研究。

在这里，我们提出了符合性整合的符号回归（SISR），这是一种从数据中学习物理控制方程的新技术。SISR使用具有突变的多层LSTM-RNN采用深层符号回归方法，以概率地采样哈密顿符号表达式。使用符号神经网络，我们开发了一种模型无关的方法，用于从数据中提取有意义的物理先验，这些方法可以直接施加到RNN输出中，从而限制了其搜索空间。使用四阶符号整合方案对RNN产生的汉密尔顿人进行了优化和评估；预测性能用于训练LSTM-RNN，以通过寻求风险的政策梯度方法来产生越来越更好的功能。采用这些技术，我们从振荡器，摆，两体和三体重力系统中提取正确的管理方程，并具有嘈杂且非常小的数据集。

停止词几乎没有语义信息，并经常从文本数据中删除，以减少数据集大小并改善机器学习模型的性能。因此，研究人员试图开发用于生成有效止血器集的技术。先前的方法范围从依赖语言专家的定性技术到使用在语料库中计算的相关性或频率依赖性指标提取单词重要性的统计方法。我们提出了一种新颖的定量方法，该方法采用迭代和递归特征删除算法来查看哪些单词可以从预先训练的变压器的词汇中删除，最少降级到其性能，特别是用于情感分析的任务。从经验上讲，通过这种方法生成的停止列表大大降低了数据集的大小，同时却忽略了模型性能，在此类示例中，将语料库缩小了28.4％，同时将训练有素的逻辑回归模型的准确性提高了0.25％。在另一种情况下，该语料库的准确性下降了63.7％，而精度降低了2.8％。这些有希望的结果表明，我们的方法可以为特定的NLP任务生成非常有效的停止词集。

The performance of inertial navigation systems is largely dependent on the stable flow of external measurements and information to guarantee continuous filter updates and bind the inertial solution drift. Platforms in different operational environments may be prevented at some point from receiving external measurements, thus exposing their navigation solution to drift. Over the years, a wide variety of works have been proposed to overcome this shortcoming, by exploiting knowledge of the system current conditions and turning it into an applicable source of information to update the navigation filter. This paper aims to provide an extensive survey of information aided navigation, broadly classified into direct, indirect, and model aiding. Each approach is described by the notable works that implemented its concept, use cases, relevant state updates, and their corresponding measurement models. By matching the appropriate constraint to a given scenario, one will be able to improve the navigation solution accuracy, compensate for the lost information, and uncover certain internal states, that would otherwise remain unobservable.

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.

In the present work we propose an unsupervised ensemble method consisting of oblique trees that can address the task of auto-encoding, namely Oblique Forest AutoEncoders (briefly OF-AE). Our method is a natural extension of the eForest encoder introduced in [1]. More precisely, by employing oblique splits consisting in multivariate linear combination of features instead of the axis-parallel ones, we will devise an auto-encoder method through the computation of a sparse solution of a set of linear inequalities consisting of feature values constraints. The code for reproducing our results is available at https://github.com/CDAlecsa/Oblique-Forest-AutoEncoders.

When robots learn reward functions using high capacity models that take raw state directly as input, they need to both learn a representation for what matters in the task -- the task ``features" -- as well as how to combine these features into a single objective. If they try to do both at once from input designed to teach the full reward function, it is easy to end up with a representation that contains spurious correlations in the data, which fails to generalize to new settings. Instead, our ultimate goal is to enable robots to identify and isolate the causal features that people actually care about and use when they represent states and behavior. Our idea is that we can tune into this representation by asking users what behaviors they consider similar: behaviors will be similar if the features that matter are similar, even if low-level behavior is different; conversely, behaviors will be different if even one of the features that matter differs. This, in turn, is what enables the robot to disambiguate between what needs to go into the representation versus what is spurious, as well as what aspects of behavior can be compressed together versus not. The notion of learning representations based on similarity has a nice parallel in contrastive learning, a self-supervised representation learning technique that maps visually similar data points to similar embeddings, where similarity is defined by a designer through data augmentation heuristics. By contrast, in order to learn the representations that people use, so we can learn their preferences and objectives, we use their definition of similarity. In simulation as well as in a user study, we show that learning through such similarity queries leads to representations that, while far from perfect, are indeed more generalizable than self-supervised and task-input alternatives.

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.

Deep learning models are known to put the privacy of their training data at risk, which poses challenges for their safe and ethical release to the public. Differentially private stochastic gradient descent is the de facto standard for training neural networks without leaking sensitive information about the training data. However, applying it to models for graph-structured data poses a novel challenge: unlike with i.i.d. data, sensitive information about a node in a graph cannot only leak through its gradients, but also through the gradients of all nodes within a larger neighborhood. In practice, this limits privacy-preserving deep learning on graphs to very shallow graph neural networks. We propose to solve this issue by training graph neural networks on disjoint subgraphs of a given training graph. We develop three random-walk-based methods for generating such disjoint subgraphs and perform a careful analysis of the data-generating distributions to provide strong privacy guarantees. Through extensive experiments, we show that our method greatly outperforms the state-of-the-art baseline on three large graphs, and matches or outperforms it on four smaller ones.