在过去的几年中,图形神经网络(GNN)已成为图形分类的事实上的选择模型。尽管从理论观点来看,大多数GNN可以在任何大小的图表上操作,但从经验上观察到,当它们应用于与训练数据中的尺寸不同的尺寸的图表时,它们的分类性能会降低。以前的工作试图通过为模型提供从图形生成过程的假设或需要从测试域中访问图形的模型来解决图形分类中的此问题。第一个策略与使用临时模型以及在生成过程中做出的假设的质量有关,这使如何在一般环境中改善通用GNN模型的性能。另一方面,第二种策略可以应用于任何GNN,但需要访问并不总是容易获得的信息。在这项工作中,我们考虑只有访问培训数据的情况,我们提出了一种正则化策略,可以应用于任何GNN,以将其概括能力从较小的图表提高到较大的图表,而无需访问测试数据。我们的正则化是基于模拟使用粗糙技术模拟训练图的大小的想法,并强制实施模型以稳健地进行这种转变。标准数据集的实验结果表明,受欢迎的GNN模型在数据集中的50%最小图表上进行了训练,并在10%最大的图表上进行了测试,在接受我们的正则化策略培训时,可获得高达30%的性能提高。
translated by 谷歌翻译
图形神经网络(GNNS)已成为图形结构化数据上许多应用的最先进的方法。 GNN是图形表示学习的框架,其中模型学习生成封装结构和特征相关信息的低维节点嵌入。 GNN通常以端到端的方式培训,导致高度专业化的节点嵌入。虽然这种方法在单任务设置中实现了很大的结果,但是可以用于执行多个任务的生成节点嵌入式(具有与单任务模型的性能)仍然是一个开放问题。我们提出了一种基于元学习的图形表示学习的新颖培训策略,这允许培训能够产生多任务节点嵌入的GNN模型。我们的方法避免了学习同时学习快速学习多个任务时产生的困难(即,具有梯度下降的几步),适应多个任务。我们表明,由我们的方法训练的模型生产的嵌入物可用于执行具有比单个任务和多任务端到端模型的可比性或令人惊讶的,甚至更高的性能的多个任务。
translated by 谷歌翻译
图形神经网络(GNNS)依赖于图形结构来定义聚合策略,其中每个节点通过与邻居的信息组合来更新其表示。已知GNN的限制是,随着层数的增加,信息被平滑,压扁并且节点嵌入式变得无法区分,对性能产生负面影响。因此,实用的GNN模型雇用了几层,只能在每个节点周围的有限邻域利用图形结构。不可避免地,实际的GNN不会根据图的全局结构捕获信息。虽然有几种研究GNNS的局限性和表达性,但是关于图形结构数据的实际应用的问题需要全局结构知识,仍然没有答案。在这项工作中,我们通过向几个GNN模型提供全球信息并观察其对下游性能的影响来认证解决这个问题。我们的研究结果表明,全球信息实际上可以为共同的图形相关任务提供显着的好处。我们进一步确定了一项新的正规化策略,导致所有考虑的任务的平均准确性提高超过5%。
translated by 谷歌翻译
Recent years have seen a proliferation of research on adversarial machine learning. Numerous papers demonstrate powerful algorithmic attacks against a wide variety of machine learning (ML) models, and numerous other papers propose defenses that can withstand most attacks. However, abundant real-world evidence suggests that actual attackers use simple tactics to subvert ML-driven systems, and as a result security practitioners have not prioritized adversarial ML defenses. Motivated by the apparent gap between researchers and practitioners, this position paper aims to bridge the two domains. We first present three real-world case studies from which we can glean practical insights unknown or neglected in research. Next we analyze all adversarial ML papers recently published in top security conferences, highlighting positive trends and blind spots. Finally, we state positions on precise and cost-driven threat modeling, collaboration between industry and academia, and reproducible research. We believe that our positions, if adopted, will increase the real-world impact of future endeavours in adversarial ML, bringing both researchers and practitioners closer to their shared goal of improving the security of ML systems.
translated by 谷歌翻译
When simulating soft robots, both their morphology and their controllers play important roles in task performance. This paper introduces a new method to co-evolve these two components in the same process. We do that by using the hyperNEAT algorithm to generate two separate neural networks in one pass, one responsible for the design of the robot body structure and the other for the control of the robot. The key difference between our method and most existing approaches is that it does not treat the development of the morphology and the controller as separate processes. Similar to nature, our method derives both the "brain" and the "body" of an agent from a single genome and develops them together. While our approach is more realistic and doesn't require an arbitrary separation of processes during evolution, it also makes the problem more complex because the search space for this single genome becomes larger and any mutation to the genome affects "brain" and the "body" at the same time. Additionally, we present a new speciation function that takes into consideration both the genotypic distance, as is the standard for NEAT, and the similarity between robot bodies. By using this function, agents with very different bodies are more likely to be in different species, this allows robots with different morphologies to have more specialized controllers since they won't crossover with other robots that are too different from them. We evaluate the presented methods on four tasks and observe that even if the search space was larger, having a single genome makes the evolution process converge faster when compared to having separated genomes for body and control. The agents in our population also show morphologies with a high degree of regularity and controllers capable of coordinating the voxels to produce the necessary movements.
translated by 谷歌翻译
Filming sport videos from an aerial view has always been a hard and an expensive task to achieve, especially in sports that require a wide open area for its normal development or the ones that put in danger human safety. Recently, a new solution arose for aerial filming based on the use of Unmanned Aerial Vehicles (UAVs), which is substantially cheaper than traditional aerial filming solutions that require conventional aircrafts like helicopters or complex structures for wide mobility. In this paper, we describe the design process followed for building a customized UAV suitable for sports aerial filming. The process includes the requirements definition, technical sizing and selection of mechanical, hardware and software technologies, as well as the whole integration and operation settings. One of the goals is to develop technologies allowing to build low cost UAVs and to manage them for a wide range of usage scenarios while achieving high levels of flexibility and automation. This work also shows some technical issues found during the development of the UAV as well as the solutions implemented.
translated by 谷歌翻译
We describe a Physics-Informed Neural Network (PINN) that simulates the flow induced by the astronomical tide in a synthetic port channel, with dimensions based on the Santos - S\~ao Vicente - Bertioga Estuarine System. PINN models aim to combine the knowledge of physical systems and data-driven machine learning models. This is done by training a neural network to minimize the residuals of the governing equations in sample points. In this work, our flow is governed by the Navier-Stokes equations with some approximations. There are two main novelties in this paper. First, we design our model to assume that the flow is periodic in time, which is not feasible in conventional simulation methods. Second, we evaluate the benefit of resampling the function evaluation points during training, which has a near zero computational cost and has been verified to improve the final model, especially for small batch sizes. Finally, we discuss some limitations of the approximations used in the Navier-Stokes equations regarding the modeling of turbulence and how it interacts with PINNs.
translated by 谷歌翻译
How would you fairly evaluate two multi-object tracking algorithms (i.e. trackers), each one employing a different object detector? Detectors keep improving, thus trackers can make less effort to estimate object states over time. Is it then fair to compare a new tracker employing a new detector with another tracker using an old detector? In this paper, we propose a novel performance measure, named Tracking Effort Measure (TEM), to evaluate trackers that use different detectors. TEM estimates the improvement that the tracker does with respect to its input data (i.e. detections) at frame level (intra-frame complexity) and sequence level (inter-frame complexity). We evaluate TEM over well-known datasets, four trackers and eight detection sets. Results show that, unlike conventional tracking evaluation measures, TEM can quantify the effort done by the tracker with a reduced correlation on the input detections. Its implementation is publicly available online at https://github.com/vpulab/MOT-evaluation.
translated by 谷歌翻译
Reinforcement learning allows machines to learn from their own experience. Nowadays, it is used in safety-critical applications, such as autonomous driving, despite being vulnerable to attacks carefully crafted to either prevent that the reinforcement learning algorithm learns an effective and reliable policy, or to induce the trained agent to make a wrong decision. The literature about the security of reinforcement learning is rapidly growing, and some surveys have been proposed to shed light on this field. However, their categorizations are insufficient for choosing an appropriate defense given the kind of system at hand. In our survey, we do not only overcome this limitation by considering a different perspective, but we also discuss the applicability of state-of-the-art attacks and defenses when reinforcement learning algorithms are used in the context of autonomous driving.
translated by 谷歌翻译
This paper describes a prototype software and hardware platform to provide support to field operators during the inspection of surface defects of non-metallic pipes. Inspection is carried out by video filming defects created on the same surface in real-time using a "smart" helmet device and other mobile devices. The work focuses on the detection and recognition of the defects which appears as colored iridescence of reflected light caused by the diffraction effect arising from the presence of internal stresses in the inspected material. The platform allows you to carry out preliminary analysis directly on the device in offline mode, and, if a connection to the network is established, the received data is transmitted to the server for post-processing to extract information about possible defects that were not detected at the previous stage. The paper presents a description of the stages of design, formal description, and implementation details of the platform. It also provides descriptions of the models used to recognize defects and examples of the result of the work.
translated by 谷歌翻译