现实世界中的大规模图形数据通常是动态而不是静态。数据随着时间的推移而出现的新节点,边缘,甚至是类,例如引用网络和研发协作网络。图形神经网络(GNNS)已成为众多关于图形结构数据的任务的标准方法。在这项工作中,我们采用了两步程序来探索GNN如何递增地适应新的未完成图形数据。首先,我们分析标准基准数据集的转换和归纳学习之间的边缘。在归纳预测后,我们将未标记的数据添加到图表中并显示模型稳定。然后,我们探索不断添加越来越多的标记数据的情况,同时考虑案例,在任何情况下都没有使用类标签注释。此外,我们在图表演变时介绍了新的类,并探索了自动检测来自先前看不见的类学的方法。为了以原则的方式处理不断发展的图形,我们提出了一个终身学习框架,用于图表数据以及评估协议。在本框架中,我们评估代表性的GNN架构。我们观察到模型参数内的隐式知识在显式知识时变得更加重要,即来自过去任务的数据,是有限的。我们发现,在开放世界节点分类中,令人惊讶地少数过去任务的数据足以达到通过从所有过去任务中记住数据达到的性能。在看不见的类检测的具有挑战性任务中,我们发现使用加权交叉熵损失对于稳定性很重要。
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大型的语言模型(PRELMS)正在彻底改变所有基准的自然语言处理。但是,它们的巨大尺寸对于小型实验室或移动设备上的部署而言是过分的。修剪和蒸馏等方法可减少模型尺寸,但通常保留相同的模型体系结构。相反,我们探索了蒸馏预告片中的更有效的架构,单词的持续乘法(CMOW),该构造将每个单词嵌入为矩阵,并使用矩阵乘法来编码序列。我们扩展了CMOW体系结构及其CMOW/CBOW-HYBRID变体,具有双向组件,以提供更具表现力的功能,在预绘制期间进行一般(任务无义的)蒸馏的单次表示,并提供了两种序列编码方案,可促进下游任务。句子对,例如句子相似性和自然语言推断。我们的基于矩阵的双向CMOW/CBOW-HYBRID模型在问题相似性和识别文本范围内的Distilbert具有竞争力,但仅使用参数数量的一半,并且在推理速度方面快三倍。除了情感分析任务SST-2和语言可接受性任务COLA外,我们匹配或超过ELMO的ELMO分数。但是,与以前的跨架结构蒸馏方法相比,我们证明了检测语言可接受性的分数增加了一倍。这表明基于基质的嵌入可用于将大型预赛提炼成竞争模型,并激励朝这个方向进行进一步的研究。
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图形神经网络(GNNS)已成为诸如节点分类等图形结构数据上的众多任务的标准方法。然而,现实世界图形通常会随着时间的推移而发展,甚至可能出现新的课程。我们将这些挑战塑造为终身学习的实例,其中学习者面临一系列任务,可能接管过去任务中获取的知识。这些知识可以明确地作为历史数据存储或隐含地存储在模型参数中。在这项工作中,我们系统地分析了隐式和明确知识的影响。因此,我们提出了一种在图中终身学习的增量培训方法,并根据$ k $ -.neighborface时间差异引入了一种新的度量,以解决历史数据中的差异。我们将培训方法应用于五个代表性GNN架构,并在三个新的终身节点分类数据集中评估它们。我们的研究结果表明,与培训图表数据的完整历史训练相比,不超过50%的GNN接收领域将至少保留95%的准确性。此外,我们的实验证实,当有更少的明确知识可用时,隐式知识变得更加重要。
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Deep learning models are known to put the privacy of their training data at risk, which poses challenges for their safe and ethical release to the public. Differentially private stochastic gradient descent is the de facto standard for training neural networks without leaking sensitive information about the training data. However, applying it to models for graph-structured data poses a novel challenge: unlike with i.i.d. data, sensitive information about a node in a graph cannot only leak through its gradients, but also through the gradients of all nodes within a larger neighborhood. In practice, this limits privacy-preserving deep learning on graphs to very shallow graph neural networks. We propose to solve this issue by training graph neural networks on disjoint subgraphs of a given training graph. We develop three random-walk-based methods for generating such disjoint subgraphs and perform a careful analysis of the data-generating distributions to provide strong privacy guarantees. Through extensive experiments, we show that our method greatly outperforms the state-of-the-art baseline on three large graphs, and matches or outperforms it on four smaller ones.
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A universal kernel is constructed whose sections approximate any causal and time-invariant filter in the fading memory category with inputs and outputs in a finite-dimensional Euclidean space. This kernel is built using the reservoir functional associated with a state-space representation of the Volterra series expansion available for any analytic fading memory filter. It is hence called the Volterra reservoir kernel. Even though the state-space representation and the corresponding reservoir feature map are defined on an infinite-dimensional tensor algebra space, the kernel map is characterized by explicit recursions that are readily computable for specific data sets when employed in estimation problems using the representer theorem. We showcase the performance of the Volterra reservoir kernel in a popular data science application in relation to bitcoin price prediction.
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Heating in private households is a major contributor to the emissions generated today. Heat pumps are a promising alternative for heat generation and are a key technology in achieving our goals of the German energy transformation and to become less dependent on fossil fuels. Today, the majority of heat pumps in the field are controlled by a simple heating curve, which is a naive mapping of the current outdoor temperature to a control action. A more advanced control approach is model predictive control (MPC) which was applied in multiple research works to heat pump control. However, MPC is heavily dependent on the building model, which has several disadvantages. Motivated by this and by recent breakthroughs in the field, this work applies deep reinforcement learning (DRL) to heat pump control in a simulated environment. Through a comparison to MPC, it could be shown that it is possible to apply DRL in a model-free manner to achieve MPC-like performance. This work extends other works which have already applied DRL to building heating operation by performing an in-depth analysis of the learned control strategies and by giving a detailed comparison of the two state-of-the-art control methods.
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Human motion prediction is a complex task as it involves forecasting variables over time on a graph of connected sensors. This is especially true in the case of few-shot learning, where we strive to forecast motion sequences for previously unseen actions based on only a few examples. Despite this, almost all related approaches for few-shot motion prediction do not incorporate the underlying graph, while it is a common component in classical motion prediction. Furthermore, state-of-the-art methods for few-shot motion prediction are restricted to motion tasks with a fixed output space meaning these tasks are all limited to the same sensor graph. In this work, we propose to extend recent works on few-shot time-series forecasting with heterogeneous attributes with graph neural networks to introduce the first few-shot motion approach that explicitly incorporates the spatial graph while also generalizing across motion tasks with heterogeneous sensors. In our experiments on motion tasks with heterogeneous sensors, we demonstrate significant performance improvements with lifts from 10.4% up to 39.3% compared to best state-of-the-art models. Moreover, we show that our model can perform on par with the best approach so far when evaluating on tasks with a fixed output space while maintaining two magnitudes fewer parameters.
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This project leverages advances in multi-agent reinforcement learning (MARL) to improve the efficiency and flexibility of order-picking systems for commercial warehouses. We envision a warehouse of the future in which dozens of mobile robots and human pickers work together to collect and deliver items within the warehouse. The fundamental problem we tackle, called the order-picking problem, is how these worker agents must coordinate their movement and actions in the warehouse to maximise performance (e.g. order throughput) under given resource constraints. Established industry methods using heuristic approaches require large engineering efforts to optimise for innately variable warehouse configurations. In contrast, the MARL framework can be flexibly applied to any warehouse configuration (e.g. size, layout, number/types of workers, item replenishment frequency) and the agents learn via a process of trial-and-error how to optimally cooperate with one another. This paper details the current status of the R&D effort initiated by Dematic and the University of Edinburgh towards a general-purpose and scalable MARL solution for the order-picking problem in realistic warehouses.
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Telling stories is an integral part of human communication which can evoke emotions and influence the affective states of the audience. Automatically modelling emotional trajectories in stories has thus attracted considerable scholarly interest. However, as most existing works have been limited to unsupervised dictionary-based approaches, there is no labelled benchmark for this task. We address this gap by introducing continuous valence and arousal annotations for an existing dataset of children's stories annotated with discrete emotion categories. We collect additional annotations for this data and map the originally categorical labels to the valence and arousal space. Leveraging recent advances in Natural Language Processing, we propose a set of novel Transformer-based methods for predicting valence and arousal signals over the course of written stories. We explore several strategies for fine-tuning a pretrained ELECTRA model and study the benefits of considering a sentence's context when inferring its emotionality. Moreover, we experiment with additional LSTM and Transformer layers. The best configuration achieves a Concordance Correlation Coefficient (CCC) of .7338 for valence and .6302 for arousal on the test set, demonstrating the suitability of our proposed approach. Our code and additional annotations are made available at https://github.com/lc0197/emotion_modelling_stories.
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Automatic video captioning aims for a holistic visual scene understanding. It requires a mechanism for capturing temporal context in video frames and the ability to comprehend the actions and associations of objects in a given timeframe. Such a system should additionally learn to abstract video sequences into sensible representations as well as to generate natural written language. While the majority of captioning models focus solely on the visual inputs, little attention has been paid to the audiovisual modality. To tackle this issue, we propose a novel two-fold approach. First, we implement a reward-guided KL Divergence to train a video captioning model which is resilient towards token permutations. Second, we utilise a Bi-Modal Hierarchical Reinforcement Learning (BMHRL) Transformer architecture to capture long-term temporal dependencies of the input data as a foundation for our hierarchical captioning module. Using our BMHRL, we show the suitability of the HRL agent in the generation of content-complete and grammatically sound sentences by achieving $4.91$, $2.23$, and $10.80$ in BLEU3, BLEU4, and METEOR scores, respectively on the ActivityNet Captions dataset. Finally, we make our BMHRL framework and trained models publicly available for users and developers at https://github.com/d-rothen/bmhrl.
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