We study the multiclass classification problem where the features come from the mixture of time-homogeneous diffusions. Specifically, the classes are discriminated by their drift functions while the diffusion coefficient is common to all classes and unknown. In this framework, we build a plug-in classifier which relies on nonparametric estimators of the drift and diffusion functions. We first establish the consistency of our classification procedure under mild assumptions and then provide rates of cnvergence under different set of assumptions. Finally, a numerical study supports our theoretical findings.
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In the brain, information is encoded, transmitted and used to inform behaviour at the level of timing of action potentials distributed over population of neurons. To implement neural-like systems in silico, to emulate neural function, and to interface successfully with the brain, neuromorphic circuits need to encode information in a way compatible to that used by populations of neuron in the brain. To facilitate the cross-talk between neuromorphic engineering and neuroscience, in this Review we first critically examine and summarize emerging recent findings about how population of neurons encode and transmit information. We examine the effects on encoding and readout of information for different features of neural population activity, namely the sparseness of neural representations, the heterogeneity of neural properties, the correlations among neurons, and the time scales (from short to long) at which neurons encode information and maintain it consistently over time. Finally, we critically elaborate on how these facts constrain the design of information coding in neuromorphic circuits. We focus primarily on the implications for designing neuromorphic circuits that communicate with the brain, as in this case it is essential that artificial and biological neurons use compatible neural codes. However, we also discuss implications for the design of neuromorphic systems for implementation or emulation of neural computation.
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The post-training quantization (PTQ) challenge of bringing quantized neural net accuracy close to original has drawn much attention driven by industry demand. Many of the methods emphasize optimization of a specific degree-of-freedom (DoF), such as quantization step size, preconditioning factors, bias fixing, often chained to others in multi-step solutions. Here we rethink quantized network parameterization in HW-aware fashion, towards a unified analysis of all quantization DoF, permitting for the first time their joint end-to-end finetuning. Our single-step simple and extendable method, dubbed quantization-aware finetuning (QFT), achieves 4-bit weight quantization results on-par with SoTA within PTQ constraints of speed and resource.
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Question answering models commonly have access to two sources of "knowledge" during inference time: (1) parametric knowledge - the factual knowledge encoded in the model weights, and (2) contextual knowledge - external knowledge (e.g., a Wikipedia passage) given to the model to generate a grounded answer. Having these two sources of knowledge entangled together is a core issue for generative QA models as it is unclear whether the answer stems from the given non-parametric knowledge or not. This unclarity has implications on issues of trust, interpretability and factuality. In this work, we propose a new paradigm in which QA models are trained to disentangle the two sources of knowledge. Using counterfactual data augmentation, we introduce a model that predicts two answers for a given question: one based on given contextual knowledge and one based on parametric knowledge. Our experiments on the Natural Questions dataset show that this approach improves the performance of QA models by making them more robust to knowledge conflicts between the two knowledge sources, while generating useful disentangled answers.
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Given a dataset of expert agent interactions with an environment of interest, a viable method to extract an effective agent policy is to estimate the maximum likelihood policy indicated by this data. This approach is commonly referred to as behavioral cloning (BC). In this work, we describe a key disadvantage of BC that arises due to the maximum likelihood objective function; namely that BC is mean-seeking with respect to the state-conditional expert action distribution when the learner's policy is represented with a Gaussian. To address this issue, we introduce a modified version of BC, Adversarial Behavioral Cloning (ABC), that exhibits mode-seeking behavior by incorporating elements of GAN (generative adversarial network) training. We evaluate ABC on toy domains and a domain based on Hopper from the DeepMind Control suite, and show that it outperforms standard BC by being mode-seeking in nature.
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当应用于自动驾驶汽车设置时,行动识别可以帮助丰富环境模型对世界的理解并改善未来行动的计划。为了改善自动驾驶汽车决策,我们在这项工作中提出了一种新型的两阶段在线行动识别系统,称为RADAC。RADAC提出了主动剂检测的问题,并在直接的两阶段管道中以进行动作检测和分类的直接识别人类活动识别中的参与者关系的想法。我们表明,我们提出的计划可以胜过ICCV2021 ROAD挑战数据集上的基线,并通过将其部署在真实的车辆平台上,我们演示了对环境中代理行动的高阶理解如何可以改善对真实自动驾驶汽车的决策。
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近期量子系统嘈杂。串扰噪声已被确定为超导噪声中间尺度量子(NISQ)设备的主要噪声来源之一。串扰源于附近Qubits上的两Q量门门的并发执行,例如\ texttt {cx}。与单独运行相比,它可能会大大提高门的错误率。可以通过调度或硬件调整来减轻串扰。然而,先前的研究在汇编的后期很晚,通常是在完成硬件映射之后的。它可能会错过优化算法逻辑,路由和串扰的巨大机会。在本文中,我们通过在早期编译阶段同时考虑所有这些因素来推动信封。我们提出了一个称为CQC的串扰感知量子程序汇编框架,该框架可以增强串扰缓解,同时实现令人满意的电路深度。此外,我们确定了从中间表示向电路转换的机会,例如,以特定的特定串扰缓解措施,例如,\ texttt {cx}梯子构造在变异的量子eigensolvers(VQE)中。通过模拟和Real IBM-Q设备进行评估表明,我们的框架可以显着将错误率降低6 $ \ times $,而与最先进的门调度相比,仅$ \ sim $ 60 \%\%的电路深度方法。特别是对于VQE,我们使用IBMQ Guadalupe证明了49 \%的回路深度减少,而对H4分子的先前ART进行了9.6 \%的保真度改善。我们的CQC框架将在GitHub上发布。
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目的是对临床文本去识别的自然语言处理(NLP)模型的评估取决于临床注释的可用性,临床注释通常由于隐私问题而受到限制。 NLP沙盒是一种通过采用联合模型到数据的方法来减轻NLP模型缺乏数据和评估框架的方法。这使得无偏见的联合模型评估无需共享多个机构的敏感数据。材料和方法我们利用Synapse协作框架,容器化软件和OpenAPI Generator来构建NLP沙盒(NLPSANDBOX.IO)。我们使用来自三个机构的数据评估了两个最先进的NLP去识别注释模型Philter和Neuroner。我们使用来自外部验证站点的数据进一步验证了模型性能。结果我们通过去识别临床模型评估证明了NLP沙箱的有用性。外部开发人员能够将其模型纳入NLP沙盒模板中,并提供用户体验反馈。讨论我们证明了使用NLP沙箱对临床文本去识别模型进行多站点评估的可行性,而无需共享数据。标准化模型和数据模式可以使模型传输和实现平稳。为了概括NLP沙箱,数据所有者和模型开发人员需要进行工作,以开发合适和标准化的模式,并调整其数据或模型以适合模式。结论NLP沙箱降低了利用临床数据进行NLP模型评估的障碍,并促进了联合会的NLP模型的联合,多站点,无偏见的评估。
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在过去的几年中,有监督的学习(SL)已确立了自己的最新数据驱动湍流建模。在SL范式中,基于数据集对模型进行了训练,该数据集通常通过应用相应的滤波器函数来从高保真解决方案中计算出先验的模型,该函数将已分离的和未分辨的流量尺度分开。对于隐式过滤的大涡模拟(LES),此方法是不可行的,因为在这里,使用的离散化本身是隐式滤波器函数。因此,通常不知道确切的滤波器形式,因此,即使有完整的解决方案可用,也无法计算相应的闭合项。强化学习(RL)范式可用于避免通过先前获得的培训数据集训练,而是通过直接与动态LES环境本身进行交互来避免这种不一致。这允许通过设计将潜在复杂的隐式LES过滤器纳入训练过程中。在这项工作中,我们应用了一个增强学习框架,以找到最佳的涡流粘度,以隐式过滤强制均匀的各向同性湍流的大型涡流模拟。为此,我们将基于卷积神经网络的策略网络制定湍流建模的任务作为RL任务,该杂志神经网络仅基于局部流量状态在时空中动态地适应LES中的涡流效率。我们证明,受过训练的模型可以提供长期稳定的模拟,并且在准确性方面,它们的表现优于建立的分析模型。此外,这些模型可以很好地推广到其他决议和离散化。因此,我们证明RL可以为一致,准确和稳定的湍流建模提供一个框架,尤其是对于隐式过滤的LE。
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视频修复旨在从多个低质量框架中恢复多个高质量的帧。现有的视频修复方法通常属于两种极端情况,即它们并行恢复所有帧,或者以复发方式恢复视频框架,这将导致不同的优点和缺点。通常,前者具有时间信息融合的优势。但是,它遭受了较大的模型尺寸和密集的内存消耗;后者的模型大小相对较小,因为它在跨帧中共享参数。但是,它缺乏远程依赖建模能力和并行性。在本文中,我们试图通过提出经常性视频恢复变压器(即RVRT)来整合两种情况的优势。 RVRT在全球经常性的框架内并行处理本地相邻框架,该框架可以在模型大小,有效性和效率之间实现良好的权衡。具体而言,RVRT将视频分为多个剪辑,并使用先前推断的剪辑功能来估计后续剪辑功能。在每个剪辑中,通过隐式特征聚合共同更新不同的帧功能。在不同的剪辑中,引导的变形注意力是为剪辑对齐对齐的,该剪辑对齐可预测整个推断的夹子中的多个相关位置,并通过注意机制汇总其特征。关于视频超分辨率,DeBlurring和DeNoising的广泛实验表明,所提出的RVRT在具有平衡模型大小,测试内存和运行时的基准数据集上实现了最先进的性能。
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