It is a common sense that datasets with high-quality data samples play an important role in artificial intelligence (AI), machine learning (ML) and related studies. However, although AI/ML has been introduced in wireless researches long time ago, few datasets are commonly used in the research community. Without a common dataset, AI-based methods proposed for wireless systems are hard to compare with both the traditional baselines and even each other. The existing wireless AI researches usually rely on datasets generated based on statistical models or ray-tracing simulations with limited environments. The statistical data hinder the trained AI models from further fine-tuning for a specific scenario, and ray-tracing data with limited environments lower down the generalization capability of the trained AI models. In this paper, we present the Wireless AI Research Dataset (WAIR-D)1, which consists of two scenarios. Scenario 1 contains 10,000 environments with sparsely dropped user equipments (UEs), and Scenario 2 contains 100 environments with densely dropped UEs. The environments are randomly picked up from more than 40 cities in the real world map. The large volume of the data guarantees that the trained AI models enjoy good generalization capability, while fine-tuning can be easily carried out on a specific chosen environment. Moreover, both the wireless channels and the corresponding environmental information are provided in WAIR-D, so that extra-information-aided communication mechanism can be designed and evaluated. WAIR-D provides the researchers benchmarks to compare their different designs or reproduce results of others. In this paper, we show the detailed construction of this dataset and examples of using it.

In split machine learning (ML), different partitions of a neural network (NN) are executed by different computing nodes, requiring a large amount of communication cost. To ease communication burden, over-the-air computation (OAC) can efficiently implement all or part of the computation at the same time of communication. Based on the proposed system, the system implementation over wireless network is introduced and we provide the problem formulation. In particular, we show that the inter-layer connection in a NN of any size can be mathematically decomposed into a set of linear precoding and combining transformations over MIMO channels. Therefore, the precoding matrix at the transmitter and the combining matrix at the receiver of each MIMO link, as well as the channel matrix itself, can jointly serve as a fully connected layer of the NN. The generalization of the proposed scheme to the conventional NNs is also introduced. Finally, we extend the proposed scheme to the widely used convolutional neural networks and demonstrate its effectiveness under both the static and quasi-static memory channel conditions with comprehensive simulations. In such a split ML system, the precoding and combining matrices are regarded as trainable parameters, while MIMO channel matrix is regarded as unknown (implicit) parameters.

可重新配置的智能表面（RIS）已成为近年来改善无线通信的有希望的技术。它通过控制具有较少硬件成本和较低功耗来控制可重新配置的被动元件来引导入射信号来创建有利的传播环境。在本文中，我们考虑了一个RIS辅助多用户多输入单输出下行链路通信系统。我们的目标是通过在接入点和RIS元件的被动波束形成向量中优化主动波束形成来最大化所有用户的加权和速率。与大多数现有的作品不同，我们考虑使用离散相移和不完美的信道状态信息（CSI）更实际的情况。具体而言，对于考虑离散相移和完美CSI的情况，我们首先开发一个深量化的神经网络（DQNN），同时设计主动和被动波束形成，而大多数报道的作品可选地设计。然后，我们基于DQNN提出改进的结构（I-DQNN），以简化参数决策过程，当每个RIS元素的控制位大于1位时。最后，我们将两种基于DQNN的算法扩展到同时考虑离散相移和不完全CSI的情况。我们的仿真结果表明，基于DQNN的两种算法比完美CSI案例中的传统算法更好，并且在不完美的CSI案例中也是更强大的。

为了减轻阴影衰落和障碍物阻塞的影响，可重新配置的智能表面（RIS）已经成为一种有前途的技术，通过控制具有较少硬件成本和更低的功耗来改善无线通信的信号传输质量。然而，由于大量的RIS被动元件，准确，低延迟和低导频和低导架频道状态信息（CSI）采集仍然是RIS辅助系统的相当大挑战。在本文中，我们提出了一个三阶段的关节通道分解和预测框架来要求CSI。所提出的框架利用了基站（BS）-RIS通道是准静态的两次时间段属性，并且RIS用户设备（UE）通道快速时变。具体而言，在第一阶段，我们使用全双工技术来估计BS的特定天线和RIS之间的信道，解决信道分解中的关键缩放模糊问题。然后，我们设计了一种新型的深度神经网络，即稀疏连接的长短期存储器（SCLSTM），并分别在第二和第三阶段提出基于SCLSTM的算法。该算法可以从级联信道同时分解BS-RIS信道和RIS-UE信道，并捕获RIS-UE信道的时间关系以进行预测。仿真结果表明，我们所提出的框架具有比传统信道估计算法更低的导频开销，并且所提出的基于SCLSTM的算法也可以鲁棒地和有效地实现更准确的CSI采集。

Terahertz频段（0.1---10 THZ）中的无线通信被视为未来第六代（6G）无线通信系统的关键促进技术之一，超出了大量多重输入多重输出（大量MIMO）技术。但是，THZ频率的非常高的传播衰减和分子吸收通常限制了信号传输距离和覆盖范围。从最近在可重构智能表面（RIS）上实现智能无线电传播环境的突破，我们为多跳RIS RIS辅助通信网络提供了一种新型的混合波束形成方案，以改善THZ波段频率的覆盖范围。特别是，部署了多个被动和可控的RIS，以协助基站（BS）和多个单人体用户之间的传输。我们通过利用最新的深钢筋学习（DRL）来应对传播损失的最新进展，研究了BS在BS和RISS上的模拟光束矩阵的联合设计。为了改善拟议的基于DRL的算法的收敛性，然后设计了两种算法，以初始化数字波束形成和使用交替优化技术的模拟波束形成矩阵。仿真结果表明，与基准相比，我们提出的方案能够改善50 \％的THZ通信范围。此外，还表明，我们提出的基于DRL的方法是解决NP-固定光束形成问题的最先进方法，尤其是当RIS辅助THZ通信网络的信号经历多个啤酒花时。

由于其快速和低功率配置，可重新配置的智能表面（RISS）最近被视为未来无线网络的节能解决方案，这在实现大规模连通性和低延迟通信方面具有增加的潜力。基于RIS的系统中的准确且低空的通道估计是通常的RIS单元元素及其独特的硬件约束，这是最关键的挑战之一。在本文中，我们专注于RIS授权的多用户多用户多输入单输出（MISO）上行链路通信系统的上行链路，并根据并行因子分解提出了一个通道估计框架，以展开所得的级联通道模型。我们为基站和RIS之间的渠道以及RIS与用户之间的渠道提供了两种迭代估计算法。一个基于交替的最小二乘（ALS），而另一个使用向量近似消息传递到迭代的迭代中，从估计的向量重建了两个未知的通道。为了从理论上评估基于ALS的算法的性能，我们得出了其估计值CRAM \'ER-RAO BOND（CRB）。我们还通过估计的通道和基本站的不同预码方案讨论了可实现的总和率计算。我们的广泛仿真结果表明，我们的算法表现优于基准方案，并且ALS技术可实现CRB。还证明，使用估计通道的总和率总是在各种设置下达到完美通道的总和，从而验证了提出的估计算法的有效性和鲁棒性。

This paper focuses on designing efficient models with low parameters and FLOPs for dense predictions. Even though CNN-based lightweight methods have achieved stunning results after years of research, trading-off model accuracy and constrained resources still need further improvements. This work rethinks the essential unity of efficient Inverted Residual Block in MobileNetv2 and effective Transformer in ViT, inductively abstracting a general concept of Meta-Mobile Block, and we argue that the specific instantiation is very important to model performance though sharing the same framework. Motivated by this phenomenon, we deduce a simple yet efficient modern \textbf{I}nverted \textbf{R}esidual \textbf{M}obile \textbf{B}lock (iRMB) for mobile applications, which absorbs CNN-like efficiency to model short-distance dependency and Transformer-like dynamic modeling capability to learn long-distance interactions. Furthermore, we design a ResNet-like 4-phase \textbf{E}fficient \textbf{MO}del (EMO) based only on a series of iRMBs for dense applications. Massive experiments on ImageNet-1K, COCO2017, and ADE20K benchmarks demonstrate the superiority of our EMO over state-of-the-art methods, \eg, our EMO-1M/2M/5M achieve 71.5, 75.1, and 78.4 Top-1 that surpass \textbf{SoTA} CNN-/Transformer-based models, while trading-off the model accuracy and efficiency well.

Supervised Question Answering systems (QA systems) rely on domain-specific human-labeled data for training. Unsupervised QA systems generate their own question-answer training pairs, typically using secondary knowledge sources to achieve this outcome. Our approach (called PIE-QG) uses Open Information Extraction (OpenIE) to generate synthetic training questions from paraphrased passages and uses the question-answer pairs as training data for a language model for a state-of-the-art QA system based on BERT. Triples in the form of <subject, predicate, object> are extracted from each passage, and questions are formed with subjects (or objects) and predicates while objects (or subjects) are considered as answers. Experimenting on five extractive QA datasets demonstrates that our technique achieves on-par performance with existing state-of-the-art QA systems with the benefit of being trained on an order of magnitude fewer documents and without any recourse to external reference data sources.

Transformer has achieved impressive successes for various computer vision tasks. However, most of existing studies require to pretrain the Transformer backbone on a large-scale labeled dataset (e.g., ImageNet) for achieving satisfactory performance, which is usually unavailable for medical images. Additionally, due to the gap between medical and natural images, the improvement generated by the ImageNet pretrained weights significantly degrades while transferring the weights to medical image processing tasks. In this paper, we propose Bootstrap Own Latent of Transformer (BOLT), a self-supervised learning approach specifically for medical image classification with the Transformer backbone. Our BOLT consists of two networks, namely online and target branches, for self-supervised representation learning. Concretely, the online network is trained to predict the target network representation of the same patch embedding tokens with a different perturbation. To maximally excavate the impact of Transformer from limited medical data, we propose an auxiliary difficulty ranking task. The Transformer is enforced to identify which branch (i.e., online/target) is processing the more difficult perturbed tokens. Overall, the Transformer endeavours itself to distill the transformation-invariant features from the perturbed tokens to simultaneously achieve difficulty measurement and maintain the consistency of self-supervised representations. The proposed BOLT is evaluated on three medical image processing tasks, i.e., skin lesion classification, knee fatigue fracture grading and diabetic retinopathy grading. The experimental results validate the superiority of our BOLT for medical image classification, compared to ImageNet pretrained weights and state-of-the-art self-supervised learning approaches.

Knowledge graph embedding (KGE), which maps entities and relations in a knowledge graph into continuous vector spaces, has achieved great success in predicting missing links in knowledge graphs. However, knowledge graphs often contain incomplete triples that are difficult to inductively infer by KGEs. To address this challenge, we resort to analogical inference and propose a novel and general self-supervised framework AnKGE to enhance KGE models with analogical inference capability. We propose an analogical object retriever that retrieves appropriate analogical objects from entity-level, relation-level, and triple-level. And in AnKGE, we train an analogy function for each level of analogical inference with the original element embedding from a well-trained KGE model as input, which outputs the analogical object embedding. In order to combine inductive inference capability from the original KGE model and analogical inference capability enhanced by AnKGE, we interpolate the analogy score with the base model score and introduce the adaptive weights in the score function for prediction. Through extensive experiments on FB15k-237 and WN18RR datasets, we show that AnKGE achieves competitive results on link prediction task and well performs analogical inference.