肾细胞癌(RCC)是一种常见的癌症,随着临床行为的变化。懒惰的RCC通常是低级的,没有坏死,可以在没有治疗的情况下监测。激进的RCC通常是高级的,如果未及时检测和治疗,可能会导致转移和死亡。虽然大多数肾脏癌在CT扫描中都检测到,但分级是基于侵入性活检或手术的组织学。确定对CT图像的侵略性在临床上很重要,因为它促进了风险分层和治疗计划。这项研究旨在使用机器学习方法来识别与病理学特征相关的放射学特征,以促进评估CT图像而不是组织学上的癌症侵略性。本文提出了一种新型的自动化方法,即按区域(Corrfabr)相关的特征聚集,用于通过利用放射学和相应的不对齐病理学图像之间的相关性来对透明细胞RCC进行分类。 CORRFABR由三个主要步骤组成:(1)特征聚集,其中从放射学和病理图像中提取区域级特征,(2)融合,放射学特征与病理特征相关的放射学特征在区域级别上学习,并且(3)在其中预测的地方学到的相关特征用于仅使用CT作为输入来区分侵略性和顽固的透明细胞RCC。因此,在训练过程中,Corrfabr从放射学和病理学图像中学习,但是在没有病理图像的情况下,Corrfabr将使用CORFABR将侵略性与顽固的透明细胞RCC区分开。 Corrfabr仅比放射学特征改善了分类性能,二进制分类F1分数从0.68(0.04)增加到0.73(0.03)。这证明了将病理疾病特征纳入CT图像上透明细胞RCC侵袭性的分类的潜力。
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前列腺活检和图像引导的治疗程序通常是在与磁共振图像(MRI)的超声指导下进行的。准确的图像融合依赖于超声图像上前列腺的准确分割。然而,超声图像中降低的信噪比和工件(例如,斑点和阴影)限制了自动前列腺分割技术的性能,并将这些方法推广到新的图像域是本质上很难的。在这项研究中,我们通过引入一种新型的2.5D深神经网络来解决这些挑战,用于超声图像上的前列腺分割。我们的方法通过组合有监督的域适应技术和知识蒸馏损失,解决了转移学习和填充方法的局限性(即,在更新模型权重时,在更新模型权重时的性能下降)。知识蒸馏损失允许保留先前学习的知识,并在新数据集上的模型填充后降低性能下降。此外,我们的方法依赖于注意模块,该模块认为模型特征定位信息以提高分割精度。我们对一个机构的764名受试者进行了培训,并仅使用后续机构中的十个受试者对我们的模型进行了审核。我们分析了方法在三个大型数据集上的性能,其中包括来自三个不同机构的2067名受试者。我们的方法达到了平均骰子相似性系数(骰子)为$ 94.0 \ pm0.03 $,而Hausdorff距离(HD95)为2.28 $ mm $,在第一机构的独立受试者中。此外,我们的模型在其他两个机构的研究中都很好地概括了(骰子:$ 91.0 \ pm0.03 $; hd95:3.7 $ mm $ and Dice:$ 82.0 \ pm0.03 $; hd95 $; hd95:7.1 $ mm $)。
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图像注册可用于量化前列腺癌患者纵向MR图像的形态变化。本文描述了改善基于学习的注册算法的发展,对于这种挑战性的临床应用程序通常具有高度可变但有限的培训数据。首先,我们报告说,潜在空间可以聚集到一个比在经过训练的注册网络深层瓶颈特征的瓶颈特征中通常发现的尺寸空间要低得多。基于此观察结果,我们提出了一种层次量化方法,使用具有约束大小的共同训练的词典来离散学习的特征向量,以改善注册网络的概括。此外,在潜在的量化空间中,独立优化了一种新颖的协作词典,以合并其他先验信息,例如对腺体或其他感兴趣的区域的分割。根据来自86名前列腺癌患者的216张真实临床图像,我们显示了这两个组件的功效。从腺体上的骰子和相应地标的目标登记误差方面,获得了统计学意义的提高注册精度,后者的实现了5.46毫米,而没有量化的基线提高了28.7 \%。实验结果还表明,在训练数据和测试数据之间,性能的差异确实被最小化了。
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迄今为止,迄今为止,众所周知,对广泛的互补临床相关任务进行了全面比较了医学图像登记方法。这限制了采用研究进展,以防止竞争方法的公平基准。在过去五年内已经探讨了许多新的学习方法,但优化,建筑或度量战略的问题非常适合仍然是开放的。 Learn2reg涵盖了广泛的解剖学:脑,腹部和胸部,方式:超声波,CT,MRI,群体:患者内部和患者内部和监督水平。我们为3D注册的培训和验证建立了较低的入境障碍,这帮助我们从20多个独特的团队中汇编了65多个单独的方法提交的结果。我们的互补度量集,包括稳健性,准确性,合理性和速度,使得能够独特地位了解当前的医学图像登记现状。进一步分析监督问题的转移性,偏见和重要性,主要是基于深度学习的方法的优越性,并将新的研究方向开放到利用GPU加速的常规优化的混合方法。
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前列腺癌是美国男人的第二致致命癌症。虽然磁共振成像(MRI)越来越多地用于引导前列腺癌诊断的靶向活组织检查,但其效用仍然受到限制,因为假阳性和假否定的高率以及较低的读者协议。机器学习方法在前列腺MRI上检测和定位癌症可以帮助标准化放射科学诠释。然而,现有的机器学习方法不仅在模型架构中不等,而且还可以在用于模型培训的地面真理标签策略中。在这项研究中,我们比较不同的标记策略,即病理证实放射科标签,整个安装组织病理学图像上的病理学家标签,以及病变水平和像素级数字病理学家标签(先前验证了组织病理学图像上的深层学习算法以预测像素 - 整个安装组织病理学图像上的Gleason模式)。我们分析这些标签对训练有素的机器学习模型的性能的影响。我们的实验表明,用它们培训的(1)放射科标签和模型可能会错过癌症,或低估癌症程度,(2)与他们培训的数字病理学家标签和模型与病理学家标签有高度的一致性,而(3)用数字病理学家培训的模型标签在两种不同疾病分布的两种不同群组中达到最佳性能,而不管使用的模型建筑如何。数字病理学家标签可以减少与人类注释相关的挑战,包括劳动力,时间,和读者间变异性,并且可以通过使可靠的机器学习模型进行培训来检测和定位前列腺癌,帮助弥合前列腺放射学和病理学之间的差距在MRI。
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The aim of this paper is to introduce a new learning procedure for neural networks and to demonstrate that it works well enough on a few small problems to be worth further investigation. The Forward-Forward algorithm replaces the forward and backward passes of backpropagation by two forward passes, one with positive (i.e. real) data and the other with negative data which could be generated by the network itself. Each layer has its own objective function which is simply to have high goodness for positive data and low goodness for negative data. The sum of the squared activities in a layer can be used as the goodness but there are many other possibilities, including minus the sum of the squared activities. If the positive and negative passes could be separated in time, the negative passes could be done offline, which would make the learning much simpler in the positive pass and allow video to be pipelined through the network without ever storing activities or stopping to propagate derivatives.
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In heterogeneous networks (HetNets), the overlap of small cells and the macro cell causes severe cross-tier interference. Although there exist some approaches to address this problem, they usually require global channel state information, which is hard to obtain in practice, and get the sub-optimal power allocation policy with high computational complexity. To overcome these limitations, we propose a multi-agent deep reinforcement learning (MADRL) based power control scheme for the HetNet, where each access point makes power control decisions independently based on local information. To promote cooperation among agents, we develop a penalty-based Q learning (PQL) algorithm for MADRL systems. By introducing regularization terms in the loss function, each agent tends to choose an experienced action with high reward when revisiting a state, and thus the policy updating speed slows down. In this way, an agent's policy can be learned by other agents more easily, resulting in a more efficient collaboration process. We then implement the proposed PQL in the considered HetNet and compare it with other distributed-training-and-execution (DTE) algorithms. Simulation results show that our proposed PQL can learn the desired power control policy from a dynamic environment where the locations of users change episodically and outperform existing DTE MADRL algorithms.
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Cell-free massive MIMO is emerging as a promising technology for future wireless communication systems, which is expected to offer uniform coverage and high spectral efficiency compared to classical cellular systems. We study in this paper how cell-free massive MIMO can support federated edge learning. Taking advantage of the additive nature of the wireless multiple access channel, over-the-air computation is exploited, where the clients send their local updates simultaneously over the same communication resource. This approach, known as over-the-air federated learning (OTA-FL), is proven to alleviate the communication overhead of federated learning over wireless networks. Considering channel correlation and only imperfect channel state information available at the central server, we propose a practical implementation of OTA-FL over cell-free massive MIMO. The convergence of the proposed implementation is studied analytically and experimentally, confirming the benefits of cell-free massive MIMO for OTA-FL.
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As an efficient graph analytical tool, graph neural networks (GNNs) have special properties that are particularly fit for the characteristics and requirements of wireless communications, exhibiting good potential for the advancement of next-generation wireless communications. This article aims to provide a comprehensive overview of the interplay between GNNs and wireless communications, including GNNs for wireless communications (GNN4Com) and wireless communications for GNNs (Com4GNN). In particular, we discuss GNN4Com based on how graphical models are constructed and introduce Com4GNN with corresponding incentives. We also highlight potential research directions to promote future research endeavors for GNNs in wireless communications.
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Dynamic evaluation of language models (LMs) adapts model parameters at test time using gradient information from previous tokens and substantially improves LM performance. However, it requires over 3x more compute than standard inference. We present Fast Weight Layers (FWLs), a neural component that provides the benefits of dynamic evaluation much more efficiently by expressing gradient updates as linear attention. A key improvement over dynamic evaluation is that FWLs can also be applied at training time so the model learns to make good use of gradient updates. FWLs can easily be added on top of existing transformer models, require relatively little extra compute or memory to run, and significantly improve language modeling perplexity.
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