卷积神经网络已使基于医学图像的诊断有了重大改进。但是,越来越明显的是,这些模型在面对虚假的相关性和数据集转移时易受性能降解,例如,领导者(例如,代表性不足的患者群体的表现不足)。在本文中,我们比较了ADNI MRI数据集上的两个分类方案:使用手动选择的体积特征的简单逻辑回归模型,以及对3D MRI数据训练的卷积神经网络。我们在面对不同的数据集拆分,训练集的性别组成和疾病阶段的情况下评估了受过训练的模型的鲁棒性。与其他成像方式中的早期工作相反,我们没有观察到培训数据集中多数组的模型性能的明确模式。取而代之的是,尽管逻辑回归对数据集组成完全可靠,但我们发现,在培训数据集中包括更多女性受试者时,男性和女性受试者的CNN性能通常会提高。我们假设这可能是由于两性病理学的固有差异。此外,在我们的分析中,Logistic回归模型优于3D CNN,强调了基于先验知识的手动特征规范的实用性,以及需要更强大的自动功能选择。
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由于过去几十年中获得的大量技术改进,因此可以使用机器人车进行水下勘探。这项工作描述了用于基于水下车辆的动态定位系统的开发。采用的方法是使用Lyapunov稳定性理论开发的,并通过基于神经网络的算法增强了不确定性和干扰补偿。通过数值模拟评估所提出的控制方案的性能。
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Recently, there has been an interest in improving the resources available in Intrusion Detection System (IDS) techniques. In this sense, several studies related to cybersecurity show that the environment invasions and information kidnapping are increasingly recurrent and complex. The criticality of the business involving operations in an environment using computing resources does not allow the vulnerability of the information. Cybersecurity has taken on a dimension within the universe of indispensable technology in corporations, and the prevention of risks of invasions into the environment is dealt with daily by Security teams. Thus, the main objective of the study was to investigate the Ensemble Learning technique using the Stacking method, supported by the Support Vector Machine (SVM) and k-Nearest Neighbour (kNN) algorithms aiming at an optimization of the results for DDoS attack detection. For this, the Intrusion Detection System concept was used with the application of the Data Mining and Machine Learning Orange tool to obtain better results
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Candidate axiom scoring is the task of assessing the acceptability of a candidate axiom against the evidence provided by known facts or data. The ability to score candidate axioms reliably is required for automated schema or ontology induction, but it can also be valuable for ontology and/or knowledge graph validation. Accurate axiom scoring heuristics are often computationally expensive, which is an issue if you wish to use them in iterative search techniques like level-wise generate-and-test or evolutionary algorithms, which require scoring a large number of candidate axioms. We address the problem of developing a predictive model as a substitute for reasoning that predicts the possibility score of candidate class axioms and is quick enough to be employed in such situations. We use a semantic similarity measure taken from an ontology's subsumption structure for this purpose. We show that the approach provided in this work can accurately learn the possibility scores of candidate OWL class axioms and that it can do so for a variety of OWL class axioms.
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Automatic Text Summarization (ATS) is becoming relevant with the growth of textual data; however, with the popularization of public large-scale datasets, some recent machine learning approaches have focused on dense models and architectures that, despite producing notable results, usually turn out in models difficult to interpret. Given the challenge behind interpretable learning-based text summarization and the importance it may have for evolving the current state of the ATS field, this work studies the application of two modern Generalized Additive Models with interactions, namely Explainable Boosting Machine and GAMI-Net, to the extractive summarization problem based on linguistic features and binary classification.
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Despite the impact of psychiatric disorders on clinical health, early-stage diagnosis remains a challenge. Machine learning studies have shown that classifiers tend to be overly narrow in the diagnosis prediction task. The overlap between conditions leads to high heterogeneity among participants that is not adequately captured by classification models. To address this issue, normative approaches have surged as an alternative method. By using a generative model to learn the distribution of healthy brain data patterns, we can identify the presence of pathologies as deviations or outliers from the distribution learned by the model. In particular, deep generative models showed great results as normative models to identify neurological lesions in the brain. However, unlike most neurological lesions, psychiatric disorders present subtle changes widespread in several brain regions, making these alterations challenging to identify. In this work, we evaluate the performance of transformer-based normative models to detect subtle brain changes expressed in adolescents and young adults. We trained our model on 3D MRI scans of neurotypical individuals (N=1,765). Then, we obtained the likelihood of neurotypical controls and psychiatric patients with early-stage schizophrenia from an independent dataset (N=93) from the Human Connectome Project. Using the predicted likelihood of the scans as a proxy for a normative score, we obtained an AUROC of 0.82 when assessing the difference between controls and individuals with early-stage schizophrenia. Our approach surpassed recent normative methods based on brain age and Gaussian Process, showing the promising use of deep generative models to help in individualised analyses.
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深度神经网络在医学图像分析中带来了显着突破。但是,由于其渴望数据的性质,医学成像项目中适度的数据集大小可能会阻碍其全部潜力。生成合成数据提供了一种有希望的替代方案,可以补充培训数据集并进行更大范围的医学图像研究。最近,扩散模型通过产生逼真的合成图像引起了计算机视觉社区的注意。在这项研究中,我们使用潜在扩散模型探索从高分辨率3D脑图像中生成合成图像。我们使用来自英国生物银行数据集的T1W MRI图像(n = 31,740)来训练我们的模型,以了解脑图像的概率分布,该脑图像以协变量为基础,例如年龄,性别和大脑结构量。我们发现我们的模型创建了现实的数据,并且可以使用条件变量有效地控制数据生成。除此之外,我们创建了一个带有100,000次脑图像的合成数据集,并使科学界公开使用。
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使用机器学习算法从未标记的文本中提取知识可能很复杂。文档分类和信息检索是两个应用程序,可以从无监督的学习(例如文本聚类和主题建模)中受益,包括探索性数据分析。但是,无监督的学习范式提出了可重复性问题。初始化可能会导致可变性,具体取决于机器学习算法。此外,关于群集几何形状,扭曲可能会产生误导。在原因中,异常值和异常的存在可能是决定因素。尽管初始化和异常问题与文本群集和主题建模相关,但作者并未找到对它们的深入分析。这项调查提供了这些亚地区的系统文献综述(2011-2022),并提出了共同的术语,因为类似的程序具有不同的术语。作者描述了研究机会,趋势和开放问题。附录总结了与审查的作品直接或间接相关的文本矢量化,分解和聚类算法的理论背景。
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在过去的几年中,无监督的域适应性(UDA)技术在计算机视觉中具有显着的重要性和流行。但是,与可用于图像的广泛文献相比,视频领域仍然相对尚未探索。另一方面,动作识别模型的性能受到域转移的严重影响。在本文中,我们提出了一种简单新颖的UDA方法,以供视频动作识别。我们的方法利用了时空变压器的最新进展来构建一个强大的源模型,从而更好地概括了目标域。此外,由于引入了来自信息瓶颈原则的新颖对齐损失术语,我们的架构将学习域不变功能。我们报告了UDA的两个视频动作识别基准的结果,显示了HMDB $ \ leftrightArrow $ ucf的最新性能,以及动力学$ \ rightarrow $ nec-Drone,这更具挑战性。这证明了我们方法在处理不同级别的域转移方面的有效性。源代码可在https://github.com/vturrisi/udavt上获得。
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强化学习(RL)通过原始像素成像和连续的控制任务在视频游戏中表现出了令人印象深刻的表现。但是,RL的性能较差,例如原始像素图像,例如原始像素图像。人们普遍认为,基于物理状态的RL策略(例如激光传感器测量值)比像素学习相比会产生更有效的样品结果。这项工作提出了一种新方法,该方法从深度地图估算中提取信息,以教授RL代理以执行无人机导航(UAV)的无地图导航。我们提出了深度模仿的对比度无监督的优先表示(DEPTH-CUPRL),该表示具有优先重播记忆的估算图像的深度。我们使用RL和对比度学习的组合,根据图像的RL问题引发。从无人驾驶汽车(UAV)对结果的分析中,可以得出结论,我们的深度cuprl方法在无MAP导航能力中对决策和优于最先进的像素的方法有效。
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