Singular value decomposition (SVD) is one of the most popular compression methods that approximate a target matrix with smaller matrices. However, standard SVD treats the parameters within the matrix with equal importance, which is a simple but unrealistic assumption. The parameters of a trained neural network model may affect task performance unevenly, which suggests non-equal importance among the parameters. Compared to SVD, the decomposition method aware of parameter importance is the more practical choice in real cases. Unlike standard SVD, weighted value decomposition is a non-convex optimization problem that lacks a closed-form solution. We systematically investigated multiple optimization strategies to tackle the problem and examined our method by compressing Transformer-based language models. Further, we designed a metric to predict when the SVD may introduce a significant performance drop, for which our method can be a rescue strategy. The extensive evaluations demonstrate that our method can perform better than current SOTA methods in compressing Transformer-based language models.
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将大型矩阵分配到小矩阵中是模型压缩的流行策略。奇异值分解(SVD)在这种压缩策略中起着至关重要的作用,近似具有较少参数的学习矩阵。但是,SVD最大程度地减少了平方误差以重建原始矩阵而不衡量参数的重要性,从而为那些影响任务准确性的人提供了更大的重建误差。换句话说,SVD的优化目标与受过训练的模型的任务准确性不符。我们通过引入Fisher信息来权衡影响模型预测的参数的重要性来分析此先前未开发的问题,进行观察并解决该问题。这个想法导致了我们的方法:Fisher加权SVD(FWSVD)。尽管我们方法的分解矩阵并没有导致较小的重建错误,但我们发现我们所得的任务准确性更接近原始模型的性能。我们使用基于变压器的语言模型进行分析,显示我们的加权SVD很大程度上减轻了不匹配的优化目标,并可以以更高的压缩率维持模型性能。我们的方法可以直接压缩特定于任务的模型,同时比需要昂贵的模型预训练的其他紧凑型模型策略更好。此外,对压缩模型的评估表明,我们的方法可以进一步降低9%至30%的参数,对任务准确性产生不大的影响。
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域分类是自然语言理解(NLU)中的基本任务,通常需要快速住宿到新的新兴域。即使新模型可访问,此约束使其无法培育所有先前的域。大多数现有的持续学习方法患有低精度和性能波动,特别是当旧数据和新数据的分布显着不同时。事实上,关键的真实问题不是没有旧数据的,而是效率效率恢复模型与整个旧数据集。是否有可能利用一些旧数据来产生高精度并保持稳定的性能,同时在不引入额外的普通公共表?在本文中,我们提出了一个可在各种环境下稳定地产生高性能的文本数据的一个封路数据不断学习模型。具体地,我们利用Fisher信息选择可以“记录”原始模型的关键信息的示例。此外,提出了一种称为动态重量整合的新颖方案,以在恢复过程中启用自由的自由学习。广泛的实验表明基线患有波动的性能,因此在实践中无用。相反,我们建议的CCFI显着且始终如一地优于平均精度高达20%的最佳最新方法,CCFI的每个组件有效地贡献了整体性能。
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诸如BERT的预先接受的语言模型在各种自然语言处理任务中显示出显着的效果。但是,这些模型通常包含数百万个参数,这可以防止它们在资源受限设备上实际部署。已知知识蒸馏,重量修剪和量化是模型压缩中的主要方向。然而,通过知识蒸馏获得的紧凑型模型即使对于相对小的压缩比也可能遭受显着的精度下降。另一方面,只有少数量化尝试专门用于自然语言处理任务。它们患有小的压缩比或较大的错误率,因为需要对超参数的手动设置,并且不支持微粒子组 - 方向量化。在本文中,我们提出了一种自动混合精密量化框架,设计用于伯特,其可以同时在亚组 - 明智的水平中进行量化和修剪。具体而言,我们所提出的方法利用可微分的神经结构搜索,搜索自动地分配每个子组中的参数的比例和精度,同时捕获冗余参数组。对BERT下游任务的广泛评估揭示了我们所提出的方法通过提供相同的模型尺寸来实现相同的性能。我们还通过将我们的解决方案与Ottherbert等正交方法相结合来展示获得极其轻量级模型的可行性。
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Existing measures and representations for trajectories have two longstanding fundamental shortcomings, i.e., they are computationally expensive and they can not guarantee the `uniqueness' property of a distance function: dist(X,Y) = 0 if and only if X=Y, where $X$ and $Y$ are two trajectories. This paper proposes a simple yet powerful way to represent trajectories and measure the similarity between two trajectories using a distributional kernel to address these shortcomings. It is a principled approach based on kernel mean embedding which has a strong theoretical underpinning. It has three distinctive features in comparison with existing approaches. (1) A distributional kernel is used for the very first time for trajectory representation and similarity measurement. (2) It does not rely on point-to-point distances which are used in most existing distances for trajectories. (3) It requires no learning, unlike existing learning and deep learning approaches. We show the generality of this new approach in three applications: (a) trajectory anomaly detection, (b) anomalous sub-trajectory detection, and (c) trajectory pattern mining. We identify that the distributional kernel has (i) a unique data-dependent property and the above uniqueness property which are the key factors that lead to its superior task-specific performance; and (ii) runtime orders of magnitude faster than existing distance measures.
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This paper presents a practical global optimization algorithm for the K-center clustering problem, which aims to select K samples as the cluster centers to minimize the maximum within-cluster distance. This algorithm is based on a reduced-space branch and bound scheme and guarantees convergence to the global optimum in a finite number of steps by only branching on the regions of centers. To improve efficiency, we have designed a two-stage decomposable lower bound, the solution of which can be derived in a closed form. In addition, we also propose several acceleration techniques to narrow down the region of centers, including bounds tightening, sample reduction, and parallelization. Extensive studies on synthetic and real-world datasets have demonstrated that our algorithm can solve the K-center problems to global optimal within 4 hours for ten million samples in the serial mode and one billion samples in the parallel mode. Moreover, compared with the state-of-the-art heuristic methods, the global optimum obtained by our algorithm can averagely reduce the objective function by 25.8% on all the synthetic and real-world datasets.
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Detecting abrupt changes in data distribution is one of the most significant tasks in streaming data analysis. Although many unsupervised Change-Point Detection (CPD) methods have been proposed recently to identify those changes, they still suffer from missing subtle changes, poor scalability, or/and sensitive to noise points. To meet these challenges, we are the first to generalise the CPD problem as a special case of the Change-Interval Detection (CID) problem. Then we propose a CID method, named iCID, based on a recent Isolation Distributional Kernel (IDK). iCID identifies the change interval if there is a high dissimilarity score between two non-homogeneous temporal adjacent intervals. The data-dependent property and finite feature map of IDK enabled iCID to efficiently identify various types of change points in data streams with the tolerance of noise points. Moreover, the proposed online and offline versions of iCID have the ability to optimise key parameter settings. The effectiveness and efficiency of iCID have been systematically verified on both synthetic and real-world datasets.
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Semantic segmentation works on the computer vision algorithm for assigning each pixel of an image into a class. The task of semantic segmentation should be performed with both accuracy and efficiency. Most of the existing deep FCNs yield to heavy computations and these networks are very power hungry, unsuitable for real-time applications on portable devices. This project analyzes current semantic segmentation models to explore the feasibility of applying these models for emergency response during catastrophic events. We compare the performance of real-time semantic segmentation models with non-real-time counterparts constrained by aerial images under oppositional settings. Furthermore, we train several models on the Flood-Net dataset, containing UAV images captured after Hurricane Harvey, and benchmark their execution on special classes such as flooded buildings vs. non-flooded buildings or flooded roads vs. non-flooded roads. In this project, we developed a real-time UNet based model and deployed that network on Jetson AGX Xavier module.
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Previous work has shown the potential of deep learning to predict renal obstruction using kidney ultrasound images. However, these image-based classifiers have been trained with the goal of single-visit inference in mind. We compare methods from video action recognition (i.e. convolutional pooling, LSTM, TSM) to adapt single-visit convolutional models to handle multiple visit inference. We demonstrate that incorporating images from a patient's past hospital visits provides only a small benefit for the prediction of obstructive hydronephrosis. Therefore, inclusion of prior ultrasounds is beneficial, but prediction based on the latest ultrasound is sufficient for patient risk stratification.
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We present the Recurrent Interface Network (RIN), a neural net architecture that allocates computation adaptively to the input according to the distribution of information, allowing it to scale to iterative generation of high-dimensional data. Hidden units of RINs are partitioned into the interface, which is locally connected to inputs, and latents, which are decoupled from inputs and can exchange information globally. The RIN block selectively reads from the interface into latents for high-capacity processing, with incremental updates written back to the interface. Stacking multiple blocks enables effective routing across local and global levels. While routing adds overhead, the cost can be amortized in recurrent computation settings where inputs change gradually while more global context persists, such as iterative generation using diffusion models. To this end, we propose a latent self-conditioning technique that "warm-starts" the latents at each iteration of the generation process. When applied to diffusion models operating directly on pixels, RINs yield state-of-the-art image and video generation without cascades or guidance, while being domain-agnostic and up to 10$\times$ more efficient compared to specialized 2D and 3D U-Nets.
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