我们提出了一种新的算法，用于在几何环境中学习隐藏的马尔可夫模型（HMM）的参数，其中观测值在Riemannian歧管中采用值。特别是，我们提升了一种瞬间算法的二阶方法，该方法将非统一的相关性纳入了更通用的环境，在该环境中，观察结果在非阳性面力的Riemannian对称空间中进行，观察可能性是Riemannian Gaussians。所得算法将其分解为Riemannian高斯混合模型估计算法，然后是一系列凸优化程序。我们通过示例证明，与现有学习者相比，学习者可以显着提高速度和数值准确性。

会话言论通常在话语水平上以松散的句法结构体现，但同时表现出连续话语的局部相干关系。事先工作已经表明，使用经常性神经网络或长短期存储器语言模型（LM）捕获较长的上下文信息可能遭受最近的偏置，而不是在远程上下文中。为了捕获词语和跨越话语之间的长期语义互动，我们提出了对话语音的自动语音识别（ASR）中语言建模的不同谈话历史融合方法。此外，引入了一种新的函数融合机制，该机制被引入熔断器并利用当前话语的声学嵌入和其相应的对话历史的语义含量以协作方式。为了塑造我们的想法，我们将ASR N-Best假设救援人员框架作为预测问题，利用BERT，一个标志性的预训练LM，作为成分车辆，以便于从给定的N最佳假设列表中选择Oracle假设。在AMI基准数据集上进行的实证实验似乎展示了我们对某些目前的线上的方法相关的可行性和功效。

端到端（E2E）神经建模已成为开发计算机辅助语言培训（CAPT）系统的一个主要思想，对基于传统发音评分的方法表示竞争性能。然而，所需的当前E2E神经方法面临至少两个关键挑战。一方面，大多数E2E方法以自回归方式使用左右波束搜索操作，以指示L2学习者的发音。然而，这导致推理速度非常慢，这不可避免地阻碍了他们的实际用途。另一方面，E2E神经方法通常是数据贪婪，同时，非训练数据量不足通常会降低误用检测和诊断（MD＆D）的疗效。作为回应，我们提出了一种新的MD＆D方法，利用非归共（NAR）E2E神经建模，以大大加速推理时间，同时通过传统的E2E神经方法保持性能。此外，我们设计并开发了堆叠在我们的方法的NAR E2E模型之上的发音建模网络，以进一步提高MD＆D的有效性。与某些直接的E2E模型和基于DNN-HMM声学模型构建的基于ICONIC发音评分的方法相比，在L2-arctic英语数据集上进行的经验实验似乎验证了我们方法的可行性。

Contextualized representation models such as ELMo (Peters et al., 2018a) and BERT (Devlin et al., 2018) have recently achieved state-of-the-art results on a diverse array of downstream NLP tasks. Building on recent token-level probing work, we introduce a novel edge probing task design and construct a broad suite of sub-sentence tasks derived from the traditional structured NLP pipeline. We probe word-level contextual representations from four recent models and investigate how they encode sentence structure across a range of syntactic, semantic, local, and long-range phenomena. We find that existing models trained on language modeling and translation produce strong representations for syntactic phenomena, but only offer comparably small improvements on semantic tasks over a non-contextual baseline.

The evolution of wireless communications into 6G and beyond is expected to rely on new machine learning (ML)-based capabilities. These can enable proactive decisions and actions from wireless-network components to sustain quality-of-service (QoS) and user experience. Moreover, new use cases in the area of vehicular and industrial communications will emerge. Specifically in the area of vehicle communication, vehicle-to-everything (V2X) schemes will benefit strongly from such advances. With this in mind, we have conducted a detailed measurement campaign with the purpose of enabling a plethora of diverse ML-based studies. The resulting datasets offer GPS-located wireless measurements across diverse urban environments for both cellular (with two different operators) and sidelink radio access technologies, thus enabling a variety of different studies towards V2X. The datasets are labeled and sampled with a high time resolution. Furthermore, we make the data publicly available with all the necessary information to support the on-boarding of new researchers. We provide an initial analysis of the data showing some of the challenges that ML needs to overcome and the features that ML can leverage, as well as some hints at potential research studies.

Deep learning models can achieve high accuracy when trained on large amounts of labeled data. However, real-world scenarios often involve several challenges: Training data may become available in installments, may originate from multiple different domains, and may not contain labels for training. Certain settings, for instance medical applications, often involve further restrictions that prohibit retention of previously seen data due to privacy regulations. In this work, to address such challenges, we study unsupervised segmentation in continual learning scenarios that involve domain shift. To that end, we introduce GarDA (Generative Appearance Replay for continual Domain Adaptation), a generative-replay based approach that can adapt a segmentation model sequentially to new domains with unlabeled data. In contrast to single-step unsupervised domain adaptation (UDA), continual adaptation to a sequence of domains enables leveraging and consolidation of information from multiple domains. Unlike previous approaches in incremental UDA, our method does not require access to previously seen data, making it applicable in many practical scenarios. We evaluate GarDA on two datasets with different organs and modalities, where it substantially outperforms existing techniques.

The development of social media user stance detection and bot detection methods rely heavily on large-scale and high-quality benchmarks. However, in addition to low annotation quality, existing benchmarks generally have incomplete user relationships, suppressing graph-based account detection research. To address these issues, we propose a Multi-Relational Graph-Based Twitter Account Detection Benchmark (MGTAB), the first standardized graph-based benchmark for account detection. To our knowledge, MGTAB was built based on the largest original data in the field, with over 1.55 million users and 130 million tweets. MGTAB contains 10,199 expert-annotated users and 7 types of relationships, ensuring high-quality annotation and diversified relations. In MGTAB, we extracted the 20 user property features with the greatest information gain and user tweet features as the user features. In addition, we performed a thorough evaluation of MGTAB and other public datasets. Our experiments found that graph-based approaches are generally more effective than feature-based approaches and perform better when introducing multiple relations. By analyzing experiment results, we identify effective approaches for account detection and provide potential future research directions in this field. Our benchmark and standardized evaluation procedures are freely available at: https://github.com/GraphDetec/MGTAB.

As one of the prevalent methods to achieve automation systems, Imitation Learning (IL) presents a promising performance in a wide range of domains. However, despite the considerable improvement in policy performance, the corresponding research on the explainability of IL models is still limited. Inspired by the recent approaches in explainable artificial intelligence methods, we proposed a model-agnostic explaining framework for IL models called R2RISE. R2RISE aims to explain the overall policy performance with respect to the frames in demonstrations. It iteratively retrains the black-box IL model from the randomized masked demonstrations and uses the conventional evaluation outcome environment returns as the coefficient to build an importance map. We also conducted experiments to investigate three major questions concerning frames' importance equality, the effectiveness of the importance map, and connections between importance maps from different IL models. The result shows that R2RISE successfully distinguishes important frames from the demonstrations.

Compressed videos often exhibit visually annoying artifacts, known as Perceivable Encoding Artifacts (PEAs), which dramatically degrade video visual quality. Subjective and objective measures capable of identifying and quantifying various types of PEAs are critical in improving visual quality. In this paper, we investigate the influence of four spatial PEAs (i.e. blurring, blocking, bleeding, and ringing) and two temporal PEAs (i.e. flickering and floating) on video quality. For spatial artifacts, we propose a visual saliency model with a low computational cost and higher consistency with human visual perception. In terms of temporal artifacts, self-attention based TimeSFormer is improved to detect temporal artifacts. Based on the six types of PEAs, a quality metric called Saliency-Aware Spatio-Temporal Artifacts Measurement (SSTAM) is proposed. Experimental results demonstrate that the proposed method outperforms state-of-the-art metrics. We believe that SSTAM will be beneficial for optimizing video coding techniques.

We propose a distributionally robust return-risk model for Markov decision processes (MDPs) under risk and reward ambiguity. The proposed model optimizes the weighted average of mean and percentile performances, and it covers the distributionally robust MDPs and the distributionally robust chance-constrained MDPs (both under reward ambiguity) as special cases. By considering that the unknown reward distribution lies in a Wasserstein ambiguity set, we derive the tractable reformulation for our model. In particular, we show that that the return-risk model can also account for risk from uncertain transition kernel when one only seeks deterministic policies, and that a distributionally robust MDP under the percentile criterion can be reformulated as its nominal counterpart at an adjusted risk level. A scalable first-order algorithm is designed to solve large-scale problems, and we demonstrate the advantages of our proposed model and algorithm through numerical experiments.