Human Activity Recognition (HAR) is one of the core research areas in mobile and wearable computing. With the application of deep learning (DL) techniques such as CNN, recognizing periodic or static activities (e.g, walking, lying, cycling, etc.) has become a well studied problem. What remains a major challenge though is the sporadic activity recognition (SAR) problem, where activities of interest tend to be non periodic, and occur less frequently when compared with the often large amount of irrelevant background activities. Recent works suggested that sequential DL models (such as LSTMs) have great potential for modeling nonperiodic behaviours, and in this paper we studied some LSTM training strategies for SAR. Specifically, we proposed two simple yet effective LSTM variants, namely delay model and inverse model, for two SAR scenarios (with and without time critical requirement). For time critical SAR, the delay model can effectively exploit predefined delay intervals (within tolerance) in form of contextual information for improved performance. For regular SAR task, the second proposed, inverse model can learn patterns from the time series in an inverse manner, which can be complementary to the forward model (i.e.,LSTM), and combining both can boost the performance. These two LSTM variants are very practical, and they can be deemed as training strategies without alteration of the LSTM fundamentals. We also studied some additional LSTM training strategies, which can further improve the accuracy. We evaluated our models on two SAR and one non-SAR datasets, and the promising results demonstrated the effectiveness of our approaches in HAR applications.

Generalist models, which are capable of performing diverse multi-modal tasks in a task-agnostic way within a single model, have been explored recently. Being, hopefully, an alternative to approaching general-purpose AI, existing generalist models are still at an early stage, where modality and task coverage is limited. To empower multi-modal task-scaling and speed up this line of research, we release a generalist model learning system, OFASys, built on top of a declarative task interface named multi-modal instruction. At the core of OFASys is the idea of decoupling multi-modal task representations from the underlying model implementations. In OFASys, a task involving multiple modalities can be defined declaratively even with just a single line of code. The system automatically generates task plans from such instructions for training and inference. It also facilitates multi-task training for diverse multi-modal workloads. As a starting point, we provide presets of 7 different modalities and 23 highly-diverse example tasks in OFASys, with which we also develop a first-in-kind, single model, OFA+, that can handle text, image, speech, video, and motion data. The single OFA+ model achieves 95% performance in average with only 16% parameters of 15 task-finetuned models, showcasing the performance reliability of multi-modal task-scaling provided by OFASys. Available at https://github.com/OFA-Sys/OFASys

The space-air-ground integrated network (SAGIN), one of the key technologies for next-generation mobile communication systems, can facilitate data transmission for users all over the world, especially in some remote areas where vast amounts of informative data are collected by Internet of remote things (IoRT) devices to support various data-driven artificial intelligence (AI) services. However, training AI models centrally with the assistance of SAGIN faces the challenges of highly constrained network topology, inefficient data transmission, and privacy issues. To tackle these challenges, we first propose a novel topology-aware federated learning framework for the SAGIN, namely Olive Branch Learning (OBL). Specifically, the IoRT devices in the ground layer leverage their private data to perform model training locally, while the air nodes in the air layer and the ring-structured low earth orbit (LEO) satellite constellation in the space layer are in charge of model aggregation (synchronization) at different scales.To further enhance communication efficiency and inference performance of OBL, an efficient Communication and Non-IID-aware Air node-Satellite Assignment (CNASA) algorithm is designed by taking the data class distribution of the air nodes as well as their geographic locations into account. Furthermore, we extend our OBL framework and CNASA algorithm to adapt to more complex multi-orbit satellite networks. We analyze the convergence of our OBL framework and conclude that the CNASA algorithm contributes to the fast convergence of the global model. Extensive experiments based on realistic datasets corroborate the superior performance of our algorithm over the benchmark policies.

Neuroevolution has greatly promoted Deep Neural Network (DNN) architecture design and its applications, while there is a lack of methods available across different DNN types concerning both their scale and performance. In this study, we propose a self-adaptive neuroevolution (SANE) approach to automatically construct various lightweight DNN architectures for different tasks. One of the key settings in SANE is the search space defined by cells and organs self-adapted to different DNN types. Based on this search space, a constructive evolution strategy with uniform evolution settings and operations is designed to grow DNN architectures gradually. SANE is able to self-adaptively adjust evolution exploration and exploitation to improve search efficiency. Moreover, a speciation scheme is developed to protect evolution from early convergence by restricting selection competition within species. To evaluate SANE, we carry out neuroevolution experiments to generate different DNN architectures including convolutional neural network, generative adversarial network and long short-term memory. The results illustrate that the obtained DNN architectures could have smaller scale with similar performance compared to existing DNN architectures. Our proposed SANE provides an efficient approach to self-adaptively search DNN architectures across different types.

上下文多臂强盗（MAB）是推荐系统中重要的顺序决策问题。一系列称为土匪（俱乐部）聚集的作品，利用了对用户的协作效果，并显着提高了建议质量。由于应用程序量表的日益增加和对隐私的关注，因此需求不断增加，以使用户数据分散并将匪徒学习推向本地服务器端。但是，现有的俱乐部算法是在中央服务器上可用的集中设置下设计的。我们专注于研究Bandit（FCLUB）问题的联合在线聚类，该问题旨在最大程度地减少遗憾，同时满足隐私和沟通的考虑。我们为群集检测设计了一种新的基于阶段的方案，并为解决此问题的合作强盗学习提供了一种新型的异步通信协议。为了保护用户的隐私，以前的差异隐私（DP）定义不是很合适，我们提出了一个在用户群集级别上起作用的新DP概念。我们提供了严格的证据，以证明我们的算法同时实现（聚类）DP，sublrinear沟通复杂性和sublrinear遗憾。最后，实验评估表明，与基准算法相比，我们的表现出色。

近年来，多视图学习迅速发展。尽管许多先前的研究都认为每个实例都出现在所有视图中，但在现实世界应用程序中很常见，从某些视图中丢失实例，从而导致多视图数据不完整。为了解决这个问题，我们提出了一个新型潜在的异质图网络（LHGN），以实现不完整的多视图学习，该学习旨在以灵活的方式尽可能充分地使用多个不完整的视图。通过学习统一的潜在代表，隐含地实现了不同观点之间一致性和互补性之间的权衡。为了探索样本与潜在表示之间的复杂关系，首次提出了邻域约束和视图约束，以构建异质图。最后，为了避免训练和测试阶段之间的任何不一致之处，基于图形学习的分类任务应用了转导学习技术。对现实世界数据集的广泛实验结果证明了我们模型对现有最新方法的有效性。

随着对话建议的最新进展，推荐系统能够通过对话互动积极而动态地引起用户偏好。为此，系统会定期查询用户对属性的偏好并收集其反馈。但是，大多数现有的对话推荐系统仅使用户能够提供对属性的绝对反馈。实际上，绝对反馈通常受到限制，因为用户在表达偏好时倾向于提供偏见的反馈。取而代之的是，由于用户偏好是固有的相对，因此用户通常更倾向于表达比较偏好。为了使用户能够在对话互动期间提供比较偏好，我们提出了一种基于比较的对话推荐系统。相对反馈虽然更实用，但并不容易合并，因为其反馈量表总是与用户的绝对偏好不匹配。通过有效地收集和了解交互式方式的相对反馈，我们进一步提出了一种新的Bandit算法，我们称之为RelativeConucb。与对话式推荐系统中的现有Bandit算法相比，合成和现实数据集的实验验证了我们提出的方法的优势。

基于深度学习的无监督光流估计器由于对地面真理的成本和难度而引起了越来越多的关注。尽管多年来通过平均终点误差（EPE）衡量的性能有所提高，但沿运动边界（MBS）的流量估计仍然较差，而流动不平稳，通常假定的流动不平滑，而神经网络计算的功能为多个动作污染。为了改善无监督的设置中的流量，我们设计了一个框架，该框架通过分析沿边界候选者的视觉变化来检测MB，并用更远的动作取代接近检测的动作。我们提出的算法比具有相同输入的基线方法更准确地检测边界，并且可以改善任何流动预测变量的估计值，而无需额外的训练。

我们提出了Tain（视频插值的变压器和注意力），这是一个用于视频插值的残留神经网络，旨在插入中间框架，并在其周围连续两个图像框架下进行插值。我们首先提出一个新型的视觉变压器模块，称为交叉相似性（CS），以与预测插值框架相似的外观相似的外观。然后，这些CS特征用于完善插值预测。为了说明CS功能中的遮挡，我们提出了一个图像注意（IA）模块，以使网络可以从另一个框架上关注CS功能。此外，我们还使用封闭式贴片来增强培训数据集，该补丁可以跨帧移动，以改善网络对遮挡和大型运动的稳健性。由于现有方法产生平滑的预测，尤其是在MB附近，因此我们根据图像梯度使用额外的训练损失来产生更清晰的预测。胜过不需要流量估计并与基于流程的方法相当执行的现有方法，同时在VIMEO90K，UCF101和SNU-FILM基准的推理时间上具有计算有效的效率。

为了更好地利用搜索日志和建模用户的行为模式，提出了许多点击模型来提取用户的隐式交互反馈。大多数传统点击模型都是基于概率图形模型（PGM）框架，该框架需要手动设计的依赖项，并且可能会过度简化用户行为。最近，提出了基于神经网络的方法来通过增强表达能力并允许灵活的依赖性来提高用户行为的预测准确性。但是，他们仍然遭受数据稀疏性和冷启动问题的困扰。在本文中，我们提出了一个新颖的图形增强点击模型（GraphCM），用于Web搜索。首先，我们将每个查询或文档视为顶点，并分别针对查询和文档提出新颖的均匀图构造方法，以完全利用会议内和会议间信息，以解决稀疏性和冷启动问题。其次，在考试假设之后，我们分别对吸引力估计量和检查预测值进行了建模，以输出吸引力得分和检查概率，在该分数中，应用图形神经网络和邻居相互作用技术用于提取在预构建的同质图中编码的辅助信息。最后，我们将组合功能应用于将考试概率和吸引力得分整合到点击预测中。在三个现实世界会话数据集上进行的广泛实验表明，GraphCM不仅胜过了最先进的模型，而且还可以在解决数据稀疏性和冷启动问题方面取得卓越的性能。