双层金属管(BMT)在工程应用中起着极其至关重要的作用,旋转弯曲弯曲(RDB)可以实现高精度弯曲处理,但是,该产品将进一步弹回。由于BMT的复杂结构和数据集获取的高成本,基于机制研究和机器学习的现有方法无法满足Spresback预测的工程要求。根据初步机制分析,提出了物理逻辑增强网络(PE-NET)。该体系结构包括ES-NET等效BMT与单层管等效,SP-NET用于带有足够的单层管样品的浮回本的最终预测。具体而言,在第一阶段,通过理论驱动的预探测和数据驱动的预处理,ES-NET和SP-NET分别构建。在第二阶段,在物理逻辑下,PE-NET由ES-NET和SP-NET组装,然后与小样本BMT数据集和复合损耗函数进行微调。 FE模拟数据集,小样本数据集BMT BMT弹回角预测验证了所提出方法的有效性和稳定性,并证明了跨性别和工程应用程序的潜在方法。
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主流对象检测器通常由两个子任务组成,包括由两个并行头部实现的分类和回归任务。这种经典的设计范式不可避免地会导致分类得分和本地化质量(IOU)之间的空间分布不一致。因此,本文从知识蒸馏的角度来减轻这种错位。首先,我们观察到,与轻量级学生相比,庞大的老师获得的和谐预测比例更高。基于这个有趣的观察,设计了一种新颖的和谐评分(HS),以估计分类和回归质量的一致性。 HS对两个子任务之间的关系进行建模,并被视为先验知识,以促进学生的和谐预测。其次,这种空间未对准将在提炼特征时会导致选择性区域的选择。为了减轻这个问题,通过灵活平衡分类和回归任务的贡献,提出了一种新颖的任务功能蒸馏(TFD)。最终,HD和TFD构成了所提出的方法,称为任务均衡蒸馏(TBD)。广泛的实验证明了该方法的巨大潜力和概括。具体而言,当配备TBD时,带有Resnet-50的视网膜在可可基准下获得41.0地图,表现优于最近的FGD和FRS。
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作为使用最广泛的金属管弯曲方法之一,旋转拉动弯曲(RDB)过程可实现可靠和高精度的金属管弯曲(MTBF)。形成准确性受到回避和其他潜在形成缺陷的严重影响,其机制分析很难处理。同时,现有方法主要是在离线空间中进行的,忽略了物理世界中的实时信息,这是不可靠且效率低下的。为了解决这个问题,提出了基于多源输入多任务学习(MTL)的数字增强(DT增强)金属管弯曲弯曲的实时预测方法。新方法可以实现全面的MTBF实时预测。通过共享多关闭域的共同特征并在功能共享和接受层上采用组正规化策略,可以保证多源输入MTL的准确性和效率。通过DT增强,物理实时变形数据通过改进的格莱美角度场(GAF)转换在图像维度中对齐,从而实现了实际处理的反射。与传统的离线预测方法不同,新方法集成了虚拟和物理数据,以实现更有效,更准确的实时预测结果。可以实现虚拟系统和物理系统之间的DT映射连接。为了排除设备误差的影响,在物理实验验证的FE模拟方案上验证了所提出的方法的有效性。同时,将通用的预训练网络与提出的方法进行比较。结果表明,所提出的DT增强预测方法更准确和有效。
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安全已成为对现实世界系统应用深度加固学习的主要挑战之一。目前,诸如人类监督等外部知识的纳入唯一可以防止代理人访问灾难性状态的手段。在本文中,我们提出了一种基于安全模型的强化学习的新框架MBHI,可确保状态级安全,可以有效地避免“本地”和“非本地”灾难。监督学习者的合并在MBHI培训,以模仿人类阻止决策。类似于人类决策过程,MBHI将在执行对环境的动作之前在动态模型中推出一个想象的轨迹,并估算其安全性。当想象力遇到灾难时,MBHI将阻止当前的动作并使用高效的MPC方法来输出安全策略。我们在几个安全任务中评估了我们的方法,结果表明,与基线相比,MBHI在样品效率和灾难数方面取得了更好的性能。
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Although many studies have successfully applied transfer learning to medical image segmentation, very few of them have investigated the selection strategy when multiple source tasks are available for transfer. In this paper, we propose a prior knowledge guided and transferability based framework to select the best source tasks among a collection of brain image segmentation tasks, to improve the transfer learning performance on the given target task. The framework consists of modality analysis, RoI (region of interest) analysis, and transferability estimation, such that the source task selection can be refined step by step. Specifically, we adapt the state-of-the-art analytical transferability estimation metrics to medical image segmentation tasks and further show that their performance can be significantly boosted by filtering candidate source tasks based on modality and RoI characteristics. Our experiments on brain matter, brain tumor, and white matter hyperintensities segmentation datasets reveal that transferring from different tasks under the same modality is often more successful than transferring from the same task under different modalities. Furthermore, within the same modality, transferring from the source task that has stronger RoI shape similarity with the target task can significantly improve the final transfer performance. And such similarity can be captured using the Structural Similarity index in the label space.
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Modern deep neural networks have achieved superhuman performance in tasks from image classification to game play. Surprisingly, these various complex systems with massive amounts of parameters exhibit the same remarkable structural properties in their last-layer features and classifiers across canonical datasets. This phenomenon is known as "Neural Collapse," and it was discovered empirically by Papyan et al. \cite{Papyan20}. Recent papers have theoretically shown the global solutions to the training network problem under a simplified "unconstrained feature model" exhibiting this phenomenon. We take a step further and prove the Neural Collapse occurrence for deep linear network for the popular mean squared error (MSE) and cross entropy (CE) loss. Furthermore, we extend our research to imbalanced data for MSE loss and present the first geometric analysis for Neural Collapse under this setting.
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In this paper we derive a PAC-Bayesian-Like error bound for a class of stochastic dynamical systems with inputs, namely, for linear time-invariant stochastic state-space models (stochastic LTI systems for short). This class of systems is widely used in control engineering and econometrics, in particular, they represent a special case of recurrent neural networks. In this paper we 1) formalize the learning problem for stochastic LTI systems with inputs, 2) derive a PAC-Bayesian-Like error bound for such systems, 3) discuss various consequences of this error bound.
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Denoising Diffusion Probabilistic Models (DDPMs) are emerging in text-to-speech (TTS) synthesis because of their strong capability of generating high-fidelity samples. However, their iterative refinement process in high-dimensional data space results in slow inference speed, which restricts their application in real-time systems. Previous works have explored speeding up by minimizing the number of inference steps but at the cost of sample quality. In this work, to improve the inference speed for DDPM-based TTS model while achieving high sample quality, we propose ResGrad, a lightweight diffusion model which learns to refine the output spectrogram of an existing TTS model (e.g., FastSpeech 2) by predicting the residual between the model output and the corresponding ground-truth speech. ResGrad has several advantages: 1) Compare with other acceleration methods for DDPM which need to synthesize speech from scratch, ResGrad reduces the complexity of task by changing the generation target from ground-truth mel-spectrogram to the residual, resulting into a more lightweight model and thus a smaller real-time factor. 2) ResGrad is employed in the inference process of the existing TTS model in a plug-and-play way, without re-training this model. We verify ResGrad on the single-speaker dataset LJSpeech and two more challenging datasets with multiple speakers (LibriTTS) and high sampling rate (VCTK). Experimental results show that in comparison with other speed-up methods of DDPMs: 1) ResGrad achieves better sample quality with the same inference speed measured by real-time factor; 2) with similar speech quality, ResGrad synthesizes speech faster than baseline methods by more than 10 times. Audio samples are available at https://resgrad1.github.io/.
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Deep learning has been widely used for protein engineering. However, it is limited by the lack of sufficient experimental data to train an accurate model for predicting the functional fitness of high-order mutants. Here, we develop SESNet, a supervised deep-learning model to predict the fitness for protein mutants by leveraging both sequence and structure information, and exploiting attention mechanism. Our model integrates local evolutionary context from homologous sequences, the global evolutionary context encoding rich semantic from the universal protein sequence space and the structure information accounting for the microenvironment around each residue in a protein. We show that SESNet outperforms state-of-the-art models for predicting the sequence-function relationship on 26 deep mutational scanning datasets. More importantly, we propose a data augmentation strategy by leveraging the data from unsupervised models to pre-train our model. After that, our model can achieve strikingly high accuracy in prediction of the fitness of protein mutants, especially for the higher order variants (> 4 mutation sites), when finetuned by using only a small number of experimental mutation data (<50). The strategy proposed is of great practical value as the required experimental effort, i.e., producing a few tens of experimental mutation data on a given protein, is generally affordable by an ordinary biochemical group and can be applied on almost any protein.
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Deep neural networks (DNNs) are found to be vulnerable to adversarial attacks, and various methods have been proposed for the defense. Among these methods, adversarial training has been drawing increasing attention because of its simplicity and effectiveness. However, the performance of the adversarial training is greatly limited by the architectures of target DNNs, which often makes the resulting DNNs with poor accuracy and unsatisfactory robustness. To address this problem, we propose DSARA to automatically search for the neural architectures that are accurate and robust after adversarial training. In particular, we design a novel cell-based search space specially for adversarial training, which improves the accuracy and the robustness upper bound of the searched architectures by carefully designing the placement of the cells and the proportional relationship of the filter numbers. Then we propose a two-stage search strategy to search for both accurate and robust neural architectures. At the first stage, the architecture parameters are optimized to minimize the adversarial loss, which makes full use of the effectiveness of the adversarial training in enhancing the robustness. At the second stage, the architecture parameters are optimized to minimize both the natural loss and the adversarial loss utilizing the proposed multi-objective adversarial training method, so that the searched neural architectures are both accurate and robust. We evaluate the proposed algorithm under natural data and various adversarial attacks, which reveals the superiority of the proposed method in terms of both accurate and robust architectures. We also conclude that accurate and robust neural architectures tend to deploy very different structures near the input and the output, which has great practical significance on both hand-crafting and automatically designing of accurate and robust neural architectures.
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