即使在实践中无法计算其可能性,基于模拟的推断也能够学习模型的参数。一类方法使用用不同参数模拟的数据来推断摊销估计器,以获得似然到证据比,或等效的后函数。我们表明,可以在模型参数和模拟数据之间的相互信息最大化方面配制这种方法。我们使用此等价来重新诠释摊销推理的现有方法,并提出了两种依赖于互信息的下限的新方法。我们使用人工神经网络用于后部预测的采样轨迹,将框架应用于随机过程和混沌动态系统的推动。我们的方法提供了一个统一的框架,利用了相互信息估计的功率进行推理。
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需要对连续随机过程的离散化进行数字地模拟它们或从实验时间序列推断模型。然而,根据过程的性质,如果不够准确,则相同的离散化方案可以对这两个任务非常不同。在任何规模上同样良好工作的精确离散化是在粗晶体下的不变性的特征。通过这种观察,我们为自动回归模型产生的高斯时间序列构建了一种明确的重整化组方法。我们表明RG固定点对应于线性SDE的离散化,并且仅以第一阶马尔可夫进程或非马尔可夫人的形式出现。这一事实提供了对重建部分观察到的噪声驱动系统的标准延迟矢量嵌入过程失败的原因的替代说明。我们还建议基于对爱因斯坦关系的开采部分观察到的受损均衡过程的可能有效的马尔可道离散化。
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Convolutional Neural Networks (CNNs) have demonstrated superiority in learning patterns, but are sensitive to label noises and may overfit noisy labels during training. The early stopping strategy averts updating CNNs during the early training phase and is widely employed in the presence of noisy labels. Motivated by biological findings that the amplitude spectrum (AS) and phase spectrum (PS) in the frequency domain play different roles in the animal's vision system, we observe that PS, which captures more semantic information, can increase the robustness of DNNs to label noise, more so than AS can. We thus propose early stops at different times for AS and PS by disentangling the features of some layer(s) into AS and PS using Discrete Fourier Transform (DFT) during training. Our proposed Phase-AmplituDe DisentangLed Early Stopping (PADDLES) method is shown to be effective on both synthetic and real-world label-noise datasets. PADDLES outperforms other early stopping methods and obtains state-of-the-art performance.
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We present a novel neural model for modern poetry generation in French. The model consists of two pretrained neural models that are fine-tuned for the poem generation task. The encoder of the model is a RoBERTa based one while the decoder is based on GPT-2. This way the model can benefit from the superior natural language understanding performance of RoBERTa and the good natural language generation performance of GPT-2. Our evaluation shows that the model can create French poetry successfully. On a 5 point scale, the lowest score of 3.57 was given by human judges to typicality and emotionality of the output poetry while the best score of 3.79 was given to understandability.
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Graph Neural Networks (GNNs) have been successfully applied in many applications in computer sciences. Despite the success of deep learning architectures in other domains, deep GNNs still underperform their shallow counterparts. There are many open questions about deep GNNs, but over-smoothing and over-squashing are perhaps the most intriguing issues. When stacking multiple graph convolutional layers, the over-smoothing and over-squashing problems arise and have been defined as the inability of GNNs to learn deep representations and propagate information from distant nodes, respectively. Even though the widespread definitions of both problems are similar, these phenomena have been studied independently. This work strives to understand the underlying relationship between over-smoothing and over-squashing from a topological perspective. We show that both problems are intrinsically related to the spectral gap of the Laplacian of the graph. Therefore, there is a trade-off between these two problems, i.e., we cannot simultaneously alleviate both over-smoothing and over-squashing. We also propose a Stochastic Jost and Liu curvature Rewiring (SJLR) algorithm based on a bound of the Ollivier's Ricci curvature. SJLR is less expensive than previous curvature-based rewiring methods while retaining fundamental properties. Finally, we perform a thorough comparison of SJLR with previous techniques to alleviate over-smoothing or over-squashing, seeking to gain a better understanding of both problems.
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We present a novel approach to generating news headlines in Finnish for a given news story. We model this as a summarization task where a model is given a news article, and its task is to produce a concise headline describing the main topic of the article. Because there are no openly available GPT-2 models for Finnish, we will first build such a model using several corpora. The model is then fine-tuned for the headline generation task using a massive news corpus. The system is evaluated by 3 expert journalists working in a Finnish media house. The results showcase the usability of the presented approach as a headline suggestion tool to facilitate the news production process.
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We present a method for extracting a multilingual sentiment annotated dialog data set from Fallout New Vegas. The game developers have preannotated every line of dialog in the game in one of the 8 different sentiments: \textit{anger, disgust, fear, happy, neutral, pained, sad } and \textit{surprised}. The game has been translated into English, Spanish, German, French and Italian. We conduct experiments on multilingual, multilabel sentiment analysis on the extracted data set using multilingual BERT, XLMRoBERTa and language specific BERT models. In our experiments, multilingual BERT outperformed XLMRoBERTa for most of the languages, also language specific models were slightly better than multilingual BERT for most of the languages. The best overall accuracy was 54\% and it was achieved by using multilingual BERT on Spanish data. The extracted data set presents a challenging task for sentiment analysis. We have released the data, including the testing and training splits, openly on Zenodo. The data set has been shuffled for copyright reasons.
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Federated Learning (FL) enables the training of Deep Learning models without centrally collecting possibly sensitive raw data. This paves the way for stronger privacy guarantees when building predictive models. The most used algorithms for FL are parameter-averaging based schemes (e.g., Federated Averaging) that, however, have well known limits: (i) Clients must implement the same model architecture; (ii) Transmitting model weights and model updates implies high communication cost, which scales up with the number of model parameters; (iii) In presence of non-IID data distributions, parameter-averaging aggregation schemes perform poorly due to client model drifts. Federated adaptations of regular Knowledge Distillation (KD) can solve and/or mitigate the weaknesses of parameter-averaging FL algorithms while possibly introducing other trade-offs. In this article, we provide a review of KD-based algorithms tailored for specific FL issues.
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Word order, an essential property of natural languages, is injected in Transformer-based neural language models using position encoding. However, recent experiments have shown that explicit position encoding is not always useful, since some models without such feature managed to achieve state-of-the art performance on some tasks. To understand better this phenomenon, we examine the effect of removing position encodings on the pre-training objective itself (i.e., masked language modelling), to test whether models can reconstruct position information from co-occurrences alone. We do so by controlling the amount of masked tokens in the input sentence, as a proxy to affect the importance of position information for the task. We find that the necessity of position information increases with the amount of masking, and that masked language models without position encodings are not able to reconstruct this information on the task. These findings point towards a direct relationship between the amount of masking and the ability of Transformers to capture order-sensitive aspects of language using position encoding.
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3D Flash LiDAR是传统扫描激光雷达系统的替代方法,有望在紧凑的外形尺寸中进行精确的深度成像,并且没有运动部件,例如自动驾驶汽车,机器人技术和增强现实(AR)等应用。通常在图像传感器格式中使用单光子,直接飞行时间(DTOF)接收器实施,设备的操作可能会受到需要在室外场景中处理和压缩的大量光子事件的阻碍以及对较大数组的可扩展性。我们在这里提出了一个64x32像素(256x128 spad)DTOF成像器,该成像器通过将像素与嵌入式直方图使用像素一起克服这些局限性,该直方直方图锁定并跟踪返回信号。这大大降低了输出数据帧的大小,可在10 kfps范围内或100 kfps的最大帧速率进行直接深度读数。该传感器可选择性地读数检测表面或传感运动的像素,从而减少功耗和片外处理要求。我们演示了传感器在中端激光雷达中的应用。
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