我们研究了机器学习(ML)分类技术的误差概率收敛到零的速率的性能。利用大偏差理论,我们为ML分类器提供了数学条件,以表现出误差概率,这些误差概率呈指数级消失,例如$ \ sim \ exp \ left(-n \,i + o(i + o(n)\ right)$,其中$ n $是可用于测试的信息的数量(或其他相关参数,例如图像中目标的大小),而$ i $是错误率。这样的条件取决于数据驱动的决策功能的累积生成功能的Fenchel-Legendre变换(D3F,即,在做出最终二进制决策之前的阈值)在训练阶段中学到的。因此,D3F以及相关的错误率$ $ $取决于给定的训练集,该集合假定有限。有趣的是,可以根据基础统计模型的可用信息生成的可用数据集或合成数据集对这些条件进行验证和测试。换句话说,分类误差概率收敛到零,其速率可以在可用于培训的数据集的一部分上计算。与大偏差理论一致,我们还可以以足够大的$ n $为高斯分布的归一化D3F统计量来确定收敛性。利用此属性设置所需的渐近错误警报概率,从经验上来说,即使对于$ n $的非常现实的值,该属性也是准确的。此外,提供了近似错误概率曲线$ \ sim \ sim \ sim \ sim \ exp \ left(-n \,i \ right)$,这要归功于精制的渐近导数(通常称为精确的渐近学),其中$ \ zeta_n $代表$ \ zeta_n $误差概率的大多数代表性亚指数项。
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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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Bayesian optimization (BO) is one of the most effective methods for closed-loop experimental design and black-box optimization. However, a key limitation of BO is that it is an inherently sequential algorithm (one experiment is proposed per round) and thus cannot directly exploit high-throughput (parallel) experiments. Diverse modifications to the BO framework have been proposed in the literature to enable exploitation of parallel experiments but such approaches are limited in the degree of parallelization that they can achieve and can lead to redundant experiments (thus wasting resources and potentially compromising performance). In this work, we present new parallel BO paradigms that exploit the structure of the system to partition the design space. Specifically, we propose an approach that partitions the design space by following the level sets of the performance function and an approach that exploits partially-separable structures of the performance function found. We conduct extensive numerical experiments using a reactor case study to benchmark the effectiveness of these approaches against a variety of state-of-the-art parallel algorithms reported in the literature. Our computational results show that our approaches significantly reduce the required search time and increase the probability of finding a global (rather than local) solution.
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在本文中,我们研究了DRL算法在本地导航问题的应用,其中机器人仅配备有限​​量距离的外部感受传感器(例如LIDAR),在未知和混乱的工作区中朝着目标位置移动。基于DRL的碰撞避免政策具有一些优势,但是一旦他们学习合适的动作的能力仅限于传感器范围,它们就非常容易受到本地最小值的影响。由于大多数机器人在非结构化环境中执行任务,因此寻求能够避免本地最小值的广义本地导航政策,尤其是在未经训练的情况下,这是非常兴趣的。为此,我们提出了一种新颖的奖励功能,该功能结合了在训练阶段获得的地图信息,从而提高了代理商故意最佳行动方案的能力。另外,我们使用SAC算法来训练我们的ANN,这表明在最先进的文献中比其他人更有效。一组SIM到SIM和SIM到现实的实验表明,我们提出的奖励与SAC相结合的表现优于比较局部最小值和避免碰撞的方法。
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水果和蔬菜的检测,分割和跟踪是精确农业的三个基本任务,实现了机器人的收获和产量估计。但是,现代算法是饥饿的数据,并非总是有可能收集足够的数据来运用最佳性能的监督方法。由于数据收集是一项昂贵且繁琐的任务,因此在农业中使用计算机视觉的能力通常是小企业无法实现的。在此背景下的先前工作之后,我们提出了一种初始弱监督的解决方案,以减少在精确农业应用程序中获得最新检测和细分所需的数据,在这里,我们在这里改进该系统并探索跟踪果实的问题果园。我们介绍了拉齐奥南部(意大利)葡萄的葡萄园案例,因为葡萄由于遮挡,颜色和一般照明条件而难以分割。当有一些可以用作源数据的初始标记数据(例如,葡萄酒葡萄数据)时,我们会考虑这种情况,但与目标数据有很大不同(例如表格葡萄数据)。为了改善目标数据的检测和分割,我们建议使用弱边界框标签训练分割算法,而对于跟踪,我们从运动算法中利用3D结构来生成来自已标记样品的新标签。最后,将两个系统组合成完整的半监督方法。与SOTA监督解决方案的比较表明,我们的方法如何能够训练以很少的标记图像和非常简单的标签来实现高性能的新型号。
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深度学习文献通过新的架构和培训技术不断更新。然而,尽管有一些关于随机权重的发现,但最近的研究却忽略了重量初始化。另一方面,最近的作品一直在接近网络科学,以了解训练后人工神经网络(ANN)的结构和动态。因此,在这项工作中,我们分析了随机初始化网络中神经元的中心性。我们表明,较高的神经元强度方差可能会降低性能,而较低的神经元强度方差通常会改善它。然后,提出了一种新方法,根据其强度根据优先附着(PA)规则重新连接神经元连接,从而大大降低了通过常见方法初始化的层的强度方差。从这个意义上讲,重新布线仅重新组织连接,同时保留权重的大小和分布。我们通过对图像分类进行的广泛统计分析表明,在使用简单和复杂的体系结构和学习时间表时,在大多数情况下,在培训和测试过程中,性能都会提高。我们的结果表明,除了规模外,权重的组织也与更好的初始化初始化有关。
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监督运营商学习是一种新兴机器学习范例,用于建模时空动态系统的演变和近似功能数据之间的一般黑盒关系的应用。我们提出了一种新颖的操作员学习方法,LOCA(学习操作员耦合注意力),激励了最近的注意机制的成功。在我们的体系结构中,输入函数被映射到有限的一组特征,然后按照依赖于输出查询位置的注意重量平均。通过将这些注意重量与积分变换一起耦合,LOCA能够明确地学习目标输出功能中的相关性,使我们能够近似非线性运算符,即使训练集测量中的输出功能的数量非常小。我们的配方伴随着拟议模型的普遍表现力的严格近似理论保证。经验上,我们在涉及普通和部分微分方程的系统管理的若干操作员学习场景中,评估LOCA的表现,以及黑盒气候预测问题。通过这些场景,我们展示了最先进的准确性,对噪声输入数据的鲁棒性以及在测试数据集上始终如一的错误传播,即使对于分发超出预测任务。
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在这项工作中,我们提出了一种基于从Marmoset猴的大脑收集的局部场潜在数据,提出了与帕金森病相关的新生物物理计算模型。帕金森病是一种神经退行性疾病,与大量NIGRA PARSCACTCA的多巴胺能神经元的死亡有关,这影响了大脑基底神经节 - 丘脑 - 皮质神经元电路的正常动态。尽管存在多种疾病的机制,但仍然缺少这些机制和分子发病机制的完整描述,仍然没有治愈。为了解决这种差距,已经提出了类似于动物模型中发现的神经生物学方面的计算模型。在我们的模型中,我们执行了一种数据驱动方法,其中使用差分演变优化了一组生物学限制参数。进化模型成功地类似于来自健康和Parkinsonian Marmoset脑数据的单神经元均值射击和局部场势的光谱签名。据我们所知,这是帕金森病的第一个基于来自Marmoset Monkeys的七个脑区域的同时电生理学记录的第一个计算模型。结果表明,该拟议的模型可以促进PD机制的调查,并支持可以表明新疗法的技术的发展。它还可以应用于其他计算神经科学问题,其中可以使用生物数据来适应大规模模型的脑电路。
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The recent increase in public and academic interest in preserving biodiversity has led to the growth of the field of conservation technology. This field involves designing and constructing tools that utilize technology to aid in the conservation of wildlife. In this article, we will use case studies to demonstrate the importance of designing conservation tools with human-wildlife interaction in mind and provide a framework for creating successful tools. These case studies include a range of complexities, from simple cat collars to machine learning and game theory methodologies. Our goal is to introduce and inform current and future researchers in the field of conservation technology and provide references for educating the next generation of conservation technologists. Conservation technology not only has the potential to benefit biodiversity but also has broader impacts on fields such as sustainability and environmental protection. By using innovative technologies to address conservation challenges, we can find more effective and efficient solutions to protect and preserve our planet's resources.
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We present the interpretable meta neural ordinary differential equation (iMODE) method to rapidly learn generalizable (i.e., not parameter-specific) dynamics from trajectories of multiple dynamical systems that vary in their physical parameters. The iMODE method learns meta-knowledge, the functional variations of the force field of dynamical system instances without knowing the physical parameters, by adopting a bi-level optimization framework: an outer level capturing the common force field form among studied dynamical system instances and an inner level adapting to individual system instances. A priori physical knowledge can be conveniently embedded in the neural network architecture as inductive bias, such as conservative force field and Euclidean symmetry. With the learned meta-knowledge, iMODE can model an unseen system within seconds, and inversely reveal knowledge on the physical parameters of a system, or as a Neural Gauge to "measure" the physical parameters of an unseen system with observed trajectories. We test the validity of the iMODE method on bistable, double pendulum, Van der Pol, Slinky, and reaction-diffusion systems.
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