自我训练在半监督学习中表现出巨大的潜力。它的核心思想是使用在标记数据上学习的模型来生成未标记样本的伪标签,然后自我教学。为了获得有效的监督,主动尝试通常会采用动量老师进行伪标签的预测,但要观察确认偏见问题,在这种情况下,错误的预测可能会提供错误的监督信号并在培训过程中积累。这种缺点的主要原因是,现行的自我训练框架充当以前的知识指导当前状态,因为老师仅与过去的学生更新。为了减轻这个问题,我们提出了一种新颖的自我训练策略,该策略使模型可以从未来学习。具体而言,在每个培训步骤中,我们都会首先优化学生(即,在不将其应用于模型权重的情况下缓存梯度),然后用虚拟未来的学生更新老师,最后要求老师为伪标记生产伪标签目前的学生作为指导。这样,我们设法提高了伪标签的质量,从而提高了性能。我们还通过深入(FST-D)和广泛(FST-W)窥视未来,开发了我们未来自我训练(FST)框架的两个变体。将无监督的域自适应语义分割和半监督语义分割的任务作为实例,我们在广泛的环境下实验表明了我们方法的有效性和优越性。代码将公开可用。
translated by 谷歌翻译
徒手3D超声(US)由于其低成本和不受限制的视野而具有重要的临床价值。最近,深度学习算法已消除了其对笨重且昂贵的外部定位设备的依赖。然而,难以高程位移估计和大量累积漂移仍阻碍了改善重建精度。在这种情况下,我们提出了一个新颖的深度运动网络(MONET),该网络集成了图像和轻巧的传感器,从速度的角度来看,称为惯性测量单元(IMU),以减轻上述障碍。我们的贡献是两个方面。首先,我们首次介绍IMU加速度,以估计飞机外的高度位移。我们提出了一个时间和多分支结构,以挖掘低信噪比(SNR)加速度的宝贵信息。其次,我们提出了一种多模式的在线自制策略,该策略利用IMU信息作为弱标签进行自适应优化,以减少漂移错误并进一步改善加速噪声的影响。实验表明,我们所提出的方法实现了优越的重建性能,超过了最先进的方法。
translated by 谷歌翻译
政策优化方法是使用最广泛使用的加固学习(RL)算法之一。然而,对这些方法的理论理解仍然不足。即使在eoisodic(时代)的表格设置中,\ citet的基于政策方法的最先进的理论结果也是只需$ \ tilde {o}(\ sqrt {s ^ 2ah ^ 4k })$何地在$ S $是州的数量,$ a $是行动的数量,$ h $是地平线,而$ k $是剧集的数量,还有$ \ sqrt {sh} $与信息理论下限$ \ tilde {\ omega}相比,差距(\ sqrt {sah ^ 3k})$。为了弥合这样的差距,我们提出了一种新的算法基于参考的基于参考的策略优化,在任何时间保证(\ AlgnameAcro),它具有“随时稳定”的特征。我们证明我们的算法实现$ \ tilde {o}(\ sqrt {sah ^ 3k} + \ sqrt {ah ^ 4})$后悔。当$ s> h $时,我们的算法在忽略对数因子时最佳最佳。为了我们的最佳知识,RPO-SAT是第一次计算上高效,几乎最小的表格RL最佳策略算法。
translated by 谷歌翻译
最近,张等人。(2021)基于$ \ ell_ \ infty $ -distance函数开发出一种新的神经网络架构,自然拥有经过认证的$ \ ell_ \ infty $坚固的稳健性。尽管具有出色的理论特性,但到目前为止的模型只能实现与传统网络的可比性。在本文中,我们通过仔细分析培训流程,大大提高了$ \ ell_ \ infty $ -distance网的认证稳健性。特别是,我们展示了$ \ ell_p $ -rexation,这是克服模型的非平滑度的关键方法,导致早期训练阶段的意外的大型嘴唇浓度。这使得优化不足以使用铰链损耗并产生次优溶液。鉴于这些调查结果,我们提出了一种简单的方法来解决上述问题,设计一种新的客观函数,这些功能将缩放的跨熵损失结合在剪切铰链损失。实验表明,使用拟议的培训策略,$ \ ell_ \ infty $-distance网的认证准确性可以从Cifar-10($ \ epsilon = 8/255 $)的33.30%到40.06%的显着提高到40.06%,同时显着优于表现优势该地区的其他方法。我们的结果清楚地展示了$ \ ell_ \ infty $-distance净的有效性和潜力,以获得认证的稳健性。代码在https://github.com/zbh2047/l_inf-dist-net-v2上获得。
translated by 谷歌翻译
Gradient descent finds a global minimum in training deep neural networks despite the objective function being non-convex. The current paper proves gradient descent achieves zero training loss in polynomial time for a deep overparameterized neural network with residual connections (ResNet). Our analysis relies on the particular structure of the Gram matrix induced by the neural network architecture. This structure allows us to show the Gram matrix is stable throughout the training process and this stability implies the global optimality of the gradient descent algorithm. We further extend our analysis to deep residual convolutional neural networks and obtain a similar convergence result.
translated by 谷歌翻译
We present SODA: the first publicly available, million-scale high-quality social dialogue dataset. Using SODA, we train COSMO: a generalizable conversation agent outperforming previous best-performing agents on both in- and out-of-domain datasets. In contrast to most existing crowdsourced, small-scale dialogue corpora, we distill 1.5M socially-grounded dialogues from a pre-trained language model (InstructGPT; Ouyang et al., 2022). Dialogues are distilled by contextualizing social commonsense knowledge from a knowledge graph (Atomic10x; West et al., 2022). Human evaluation shows that dialogues in SODA are more consistent, specific, and (surprisingly) natural than prior human-authored datasets - e.g., DailyDialog (Li et al., 2017), BlendedSkillTalk (Smith et al., 2020). In addition, extensive evaluations show that COSMO is significantly more natural and consistent on unseen datasets than best-performing dialogue models - e.g., GODEL (Peng et al., 2022), BlenderBot (Roller et al., 2021), DialoGPT (Zhang et al., 2020). Furthermore, it is sometimes even preferred to the original human-written gold responses. We make our data, models, and code public.
translated by 谷歌翻译
Context is vital for commonsense moral reasoning. "Lying to a friend" is wrong if it is meant to deceive them, but may be morally okay if it is intended to protect them. Such nuanced but salient contextual information can potentially flip the moral judgment of an action. Thus, we present ClarifyDelphi, an interactive system that elicits missing contexts of a moral situation by generating clarification questions such as "Why did you lie to your friend?". Our approach is inspired by the observation that questions whose potential answers lead to diverging moral judgments are the most informative. We learn to generate questions using Reinforcement Learning, by maximizing the divergence between moral judgements of hypothetical answers to a question. Human evaluation shows that our system generates more relevant, informative and defeasible questions compared to other question generation baselines. ClarifyDelphi assists informed moral reasoning processes by seeking additional morally consequential context to disambiguate social and moral situations.
translated by 谷歌翻译
Multimodal machine translation (MMT) aims to improve translation quality by incorporating information from other modalities, such as vision. Previous MMT systems mainly focus on better access and use of visual information and tend to validate their methods on image-related datasets. These studies face two challenges. First, they can only utilize triple data (bilingual texts with images), which is scarce; second, current benchmarks are relatively restricted and do not correspond to realistic scenarios. Therefore, this paper correspondingly establishes new methods and new datasets for MMT. First, we propose a framework 2/3-Triplet with two new approaches to enhance MMT by utilizing large-scale non-triple data: monolingual image-text data and parallel text-only data. Second, we construct an English-Chinese {e}-commercial {m}ulti{m}odal {t}ranslation dataset (including training and testing), named EMMT, where its test set is carefully selected as some words are ambiguous and shall be translated mistakenly without the help of images. Experiments show that our method is more suitable for real-world scenarios and can significantly improve translation performance by using more non-triple data. In addition, our model also rivals various SOTA models in conventional multimodal translation benchmarks.
translated by 谷歌翻译
Real-time individual endpoint prediction has always been a challenging task but of great clinic utility for both patients and healthcare providers. With 6,879 chronic kidney disease stage 4 (CKD4) patients as a use case, we explored the feasibility and performance of gated recurrent units with decay that models Weibull probability density function (GRU-D-Weibull) as a semi-parametric longitudinal model for real-time individual endpoint prediction. GRU-D-Weibull has a maximum C-index of 0.77 at 4.3 years of follow-up, compared to 0.68 achieved by competing models. The L1-loss of GRU-D-Weibull is ~66% of XGB(AFT), ~60% of MTLR, and ~30% of AFT model at CKD4 index date. The average absolute L1-loss of GRU-D-Weibull is around one year, with a minimum of 40% Parkes serious error after index date. GRU-D-Weibull is not calibrated and significantly underestimates true survival probability. Feature importance tests indicate blood pressure becomes increasingly important during follow-up, while eGFR and blood albumin are less important. Most continuous features have non-linear/parabola impact on predicted survival time, and the results are generally consistent with existing knowledge. GRU-D-Weibull as a semi-parametric temporal model shows advantages in built-in parameterization of missing, native support for asynchronously arrived measurement, capability of output both probability and point estimates at arbitrary time point for arbitrary prediction horizon, improved discrimination and point estimate accuracy after incorporating newly arrived data. Further research on its performance with more comprehensive input features, in-process or post-process calibration are warranted to benefit CKD4 or alike terminally-ill patients.
translated by 谷歌翻译
We propose a model-data asymptotic-preserving neural network(MD-APNN) method to solve the nonlinear gray radiative transfer equations(GRTEs). The system is challenging to be simulated with both the traditional numerical schemes and the vanilla physics-informed neural networks(PINNs) due to the multiscale characteristics. Under the framework of PINNs, we employ a micro-macro decomposition technique to construct a new asymptotic-preserving(AP) loss function, which includes the residual of the governing equations in the micro-macro coupled form, the initial and boundary conditions with additional diffusion limit information, the conservation laws, and a few labeled data. A convergence analysis is performed for the proposed method, and a number of numerical examples are presented to illustrate the efficiency of MD-APNNs, and particularly, the importance of the AP property in the neural networks for the diffusion dominating problems. The numerical results indicate that MD-APNNs lead to a better performance than APNNs or pure data-driven networks in the simulation of the nonlinear non-stationary GRTEs.
translated by 谷歌翻译