Iterative detection and decoding (IDD) is known to achieve near-capacity performance in multi-antenna wireless systems. We propose deep-unfolded interleaved detection and decoding (DUIDD), a new paradigm that reduces the complexity of IDD while achieving even lower error rates. DUIDD interleaves the inner stages of the data detector and channel decoder, which expedites convergence and reduces complexity. Furthermore, DUIDD applies deep unfolding to automatically optimize algorithmic hyperparameters, soft-information exchange, message damping, and state forwarding. We demonstrate the efficacy of DUIDD using NVIDIA's Sionna link-level simulator in a 5G-near multi-user MIMO-OFDM wireless system with a novel low-complexity soft-input soft-output data detector, an optimized low-density parity-check decoder, and channel vectors from a commercial ray-tracer. Our results show that DUIDD outperforms classical IDD both in terms of block error rate and computational complexity.

在这项工作中，我们提出了一个完全可区分的图形神经网络（GNN）的架构，用于用于通道解码和展示各种编码方案的竞争性解码性能，例如低密度奇偶校验检查（LDPC）和BCH代码。这个想法是让神经网络（NN）通过给定图的通用消息传递算法，该算法通过用可训练的函数替换节点和边缘消息更新来代表正向误差校正（FEC）代码结构。与许多其他基于深度学习的解码方法相反，提出的解决方案享有对任意块长度的可扩展性，并且训练不受维数的诅咒的限制。我们在常规渠道解码中对最新的解码以及最近的基于深度学习的结果基准了我们提出的解码器。对于（63,45）BCH代码，我们的解决方案优于加权信念传播（BP）的解码约0.4 dB，而解码迭代率明显较小，甚至对于5G NR LDPC代码，我们观察到与常规BP解码相比，我们观察到竞争性能。对于BCH代码，所得的GNN解码器只能以9640个权重进行完全参数。

我们提出了一种基于神经网络（NN）的算法，用于用于窄带物理随机访问通道（NB-iot）的窄带物理随机通道（NBRACH）的设备检测和到达时间（TOA）和载体频率偏移（CFO）估计（nprach） 。引入的NN体系结构利用了剩余的卷积网络以及对5G新无线电（5G NR）规格的序言结构的了解。第三代合作伙伴项目（3GPP）城市微电池（UMI）频道模型的基准测试，其随机用户与最先进的基线相对于最先进的基线表明，该提出的方法可在虚假的负率（FNR）中最多8 dB增益（FNR）以及假阳性率（FPR）和TOA和CFO估计精度的显着增长。此外，我们的模拟表明，所提出的算法可以在广泛的通道条件，CFO和传输概率上获得收益。引入的同步方法在基站（BS）运行，因此在用户设备上没有引入其他复杂性。它可能通过降低序列长度或发射功率来延长电池寿命。我们的代码可在以下网址提供：https：//github.com/nvlabs/nprach_synch/。

这是两部分纸的第二部分，该论文着重于具有非线性接收器的多用户MIMO（MU-MIMO）系统的链接适应（LA）和物理层（PHY）抽象。第一部分提出了一个新的指标，称为检测器，称为比率解码率（BMDR），是非线性接收器的等效量等效的信号与交换后噪声比率（SINR）。由于该BMDR没有封闭形式的表达式，因此有效地提出了基于机器学习的方法来估计其。在这一部分中，第一部分中开发的概念用于开发LA的新算法，可用检测器列表中的动态检测器选择以及具有任意接收器的MU-MIMO系统中的PHY抽象。提出了证实所提出算法的功效的广泛仿真结果。

Link-Adaptation（LA）是无线通信的最重要方面之一，其中发射器使用的调制和编码方案（MCS）适用于通道条件，以满足某些目标误差率。在具有离细胞外干扰的单用户SISO（SU-SISO）系统中，LA是通过计算接收器处计算后平均值 - 交换后噪声比（SINR）进行的。可以在使用线性探测器的多用户MIMO（MU-MIMO）接收器中使用相同的技术。均衡后SINR的另一个重要用途是用于物理层（PHY）抽象，其中几个PHY块（例如通道编码器，检测器和通道解码器）被抽象模型取代，以加快系统级级别的模拟。但是，对于具有非线性接收器的MU-MIMO系统，尚无等效于平衡后的SINR，这使LA和PHY抽象都极具挑战性。这份由两部分组成的论文解决了这个重要问题。在这一部分中，提出了一个称为检测器的称为比特 - 金属解码速率（BMDR）的度量，该指标提出了相当于后平等SINR的建议。由于BMDR没有封闭形式的表达式可以启用其瞬时计算，因此一种机器学习方法可以预测其以及广泛的仿真结果。

The release of ChatGPT, a language model capable of generating text that appears human-like and authentic, has gained significant attention beyond the research community. We expect that the convincing performance of ChatGPT incentivizes users to apply it to a variety of downstream tasks, including prompting the model to simplify their own medical reports. To investigate this phenomenon, we conducted an exploratory case study. In a questionnaire, we asked 15 radiologists to assess the quality of radiology reports simplified by ChatGPT. Most radiologists agreed that the simplified reports were factually correct, complete, and not potentially harmful to the patient. Nevertheless, instances of incorrect statements, missed key medical findings, and potentially harmful passages were reported. While further studies are needed, the initial insights of this study indicate a great potential in using large language models like ChatGPT to improve patient-centered care in radiology and other medical domains.

Magnetic Resonance Fingerprinting (MRF) is an efficient quantitative MRI technique that can extract important tissue and system parameters such as T1, T2, B0, and B1 from a single scan. This property also makes it attractive for retrospectively synthesizing contrast-weighted images. In general, contrast-weighted images like T1-weighted, T2-weighted, etc., can be synthesized directly from parameter maps through spin-dynamics simulation (i.e., Bloch or Extended Phase Graph models). However, these approaches often exhibit artifacts due to imperfections in the mapping, the sequence modeling, and the data acquisition. Here we propose a supervised learning-based method that directly synthesizes contrast-weighted images from the MRF data without going through the quantitative mapping and spin-dynamics simulation. To implement our direct contrast synthesis (DCS) method, we deploy a conditional Generative Adversarial Network (GAN) framework and propose a multi-branch U-Net as the generator. The input MRF data are used to directly synthesize T1-weighted, T2-weighted, and fluid-attenuated inversion recovery (FLAIR) images through supervised training on paired MRF and target spin echo-based contrast-weighted scans. In-vivo experiments demonstrate excellent image quality compared to simulation-based contrast synthesis and previous DCS methods, both visually as well as by quantitative metrics. We also demonstrate cases where our trained model is able to mitigate in-flow and spiral off-resonance artifacts that are typically seen in MRF reconstructions and thus more faithfully represent conventional spin echo-based contrast-weighted images.

Multimodal deep learning has been used to predict clinical endpoints and diagnoses from clinical routine data. However, these models suffer from scaling issues: they have to learn pairwise interactions between each piece of information in each data type, thereby escalating model complexity beyond manageable scales. This has so far precluded a widespread use of multimodal deep learning. Here, we present a new technical approach of "learnable synergies", in which the model only selects relevant interactions between data modalities and keeps an "internal memory" of relevant data. Our approach is easily scalable and naturally adapts to multimodal data inputs from clinical routine. We demonstrate this approach on three large multimodal datasets from radiology and ophthalmology and show that it outperforms state-of-the-art models in clinically relevant diagnosis tasks. Our new approach is transferable and will allow the application of multimodal deep learning to a broad set of clinically relevant problems.

The success of Deep Learning applications critically depends on the quality and scale of the underlying training data. Generative adversarial networks (GANs) can generate arbitrary large datasets, but diversity and fidelity are limited, which has recently been addressed by denoising diffusion probabilistic models (DDPMs) whose superiority has been demonstrated on natural images. In this study, we propose Medfusion, a conditional latent DDPM for medical images. We compare our DDPM-based model against GAN-based models, which constitute the current state-of-the-art in the medical domain. Medfusion was trained and compared with (i) StyleGan-3 on n=101,442 images from the AIROGS challenge dataset to generate fundoscopies with and without glaucoma, (ii) ProGAN on n=191,027 from the CheXpert dataset to generate radiographs with and without cardiomegaly and (iii) wGAN on n=19,557 images from the CRCMS dataset to generate histopathological images with and without microsatellite stability. In the AIROGS, CRMCS, and CheXpert datasets, Medfusion achieved lower (=better) FID than the GANs (11.63 versus 20.43, 30.03 versus 49.26, and 17.28 versus 84.31). Also, fidelity (precision) and diversity (recall) were higher (=better) for Medfusion in all three datasets. Our study shows that DDPM are a superior alternative to GANs for image synthesis in the medical domain.

The availability of challenging benchmarks has played a key role in the recent progress of machine learning. In cooperative multi-agent reinforcement learning, the StarCraft Multi-Agent Challenge (SMAC) has become a popular testbed for centralised training with decentralised execution. However, after years of sustained improvement on SMAC, algorithms now achieve near-perfect performance. In this work, we conduct new analysis demonstrating that SMAC is not sufficiently stochastic to require complex closed-loop policies. In particular, we show that an open-loop policy conditioned only on the timestep can achieve non-trivial win rates for many SMAC scenarios. To address this limitation, we introduce SMACv2, a new version of the benchmark where scenarios are procedurally generated and require agents to generalise to previously unseen settings (from the same distribution) during evaluation. We show that these changes ensure the benchmark requires the use of closed-loop policies. We evaluate state-of-the-art algorithms on SMACv2 and show that it presents significant challenges not present in the original benchmark. Our analysis illustrates that SMACv2 addresses the discovered deficiencies of SMAC and can help benchmark the next generation of MARL methods. Videos of training are available at https://sites.google.com/view/smacv2