我们通过将其基于实现功能空间而不是参数空间的几何形状来系统地研究深度神经网络景观的方法。将分类器分组到等效类中,我们开发了一个标准化的参数化,其中所有对称性都被删除,从而导致环形拓扑。在这个空间上,我们探讨了误差景观而不是损失。这使我们能够得出有意义的概念,即最小化器的平坦度和连接它们的地球通道的概念。使用不同的优化算法,这些算法采样具有不同平坦度的最小化器,我们研究模式连接性和相对距离。测试各种最先进的体系结构和基准数据集,我们确认了平面度和泛化性能之间的相关性;我们进一步表明,在功能空间中,minima彼此更近,并且连接它们的大地测量学的屏障很小。我们还发现,通过梯度下降的变体发现的最小化器可以通过由参数空间中的两个直线组成的零误差路径连接,即带有单个弯曲的多边形链。我们观察到具有二进制权重和激活的神经网络中相似的定性结果,这为在这种情况下的连通性提供了第一个结果之一。我们的结果取决于对称性的去除,并且与对简单浅层模型进行的一些分析研究所描述的丰富现象学非常吻合。
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在神经网络的经验风险景观中扁平最小值的性质已经讨论了一段时间。越来越多的证据表明他们对尖锐物质具有更好的泛化能力。首先,我们讨论高斯混合分类模型,并分析显示存在贝叶斯最佳点估算器,其对应于属于宽平区域的最小值。可以通过直接在分类器(通常是独立的)或学习中使用的可分解损耗函数上应用最大平坦度算法来找到这些估计器。接下来,我们通过广泛的数值验证将分析扩展到深度学习场景。使用两种算法,熵-SGD和复制-SGD,明确地包括在优化目标中,所谓的非局部平整度措施称为本地熵,我们一直提高常见架构的泛化误差(例如Resnet,CeffectnNet)。易于计算的平坦度测量显示与测试精度明确的相关性。
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In this paper we present TruFor, a forensic framework that can be applied to a large variety of image manipulation methods, from classic cheapfakes to more recent manipulations based on deep learning. We rely on the extraction of both high-level and low-level traces through a transformer-based fusion architecture that combines the RGB image and a learned noise-sensitive fingerprint. The latter learns to embed the artifacts related to the camera internal and external processing by training only on real data in a self-supervised manner. Forgeries are detected as deviations from the expected regular pattern that characterizes each pristine image. Looking for anomalies makes the approach able to robustly detect a variety of local manipulations, ensuring generalization. In addition to a pixel-level localization map and a whole-image integrity score, our approach outputs a reliability map that highlights areas where localization predictions may be error-prone. This is particularly important in forensic applications in order to reduce false alarms and allow for a large scale analysis. Extensive experiments on several datasets show that our method is able to reliably detect and localize both cheapfakes and deepfakes manipulations outperforming state-of-the-art works. Code will be publicly available at https://grip-unina.github.io/TruFor/
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The shift of public debate to the digital sphere has been accompanied by a rise in online hate speech. While many promising approaches for hate speech classification have been proposed, studies often focus only on a single language, usually English, and do not address three key concerns: post-deployment performance, classifier maintenance and infrastructural limitations. In this paper, we introduce a new human-in-the-loop BERT-based hate speech classification pipeline and trace its development from initial data collection and annotation all the way to post-deployment. Our classifier, trained using data from our original corpus of over 422k examples, is specifically developed for the inherently multilingual setting of Switzerland and outperforms with its F1 score of 80.5 the currently best-performing BERT-based multilingual classifier by 5.8 F1 points in German and 3.6 F1 points in French. Our systematic evaluations over a 12-month period further highlight the vital importance of continuous, human-in-the-loop classifier maintenance to ensure robust hate speech classification post-deployment.
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In this paper, we introduce MINTIME, a video deepfake detection approach that captures spatial and temporal anomalies and handles instances of multiple people in the same video and variations in face sizes. Previous approaches disregard such information either by using simple a-posteriori aggregation schemes, i.e., average or max operation, or using only one identity for the inference, i.e., the largest one. On the contrary, the proposed approach builds on a Spatio-Temporal TimeSformer combined with a Convolutional Neural Network backbone to capture spatio-temporal anomalies from the face sequences of multiple identities depicted in a video. This is achieved through an Identity-aware Attention mechanism that attends to each face sequence independently based on a masking operation and facilitates video-level aggregation. In addition, two novel embeddings are employed: (i) the Temporal Coherent Positional Embedding that encodes each face sequence's temporal information and (ii) the Size Embedding that encodes the size of the faces as a ratio to the video frame size. These extensions allow our system to adapt particularly well in the wild by learning how to aggregate information of multiple identities, which is usually disregarded by other methods in the literature. It achieves state-of-the-art results on the ForgeryNet dataset with an improvement of up to 14% AUC in videos containing multiple people and demonstrates ample generalization capabilities in cross-forgery and cross-dataset settings. The code is publicly available at https://github.com/davide-coccomini/MINTIME-Multi-Identity-size-iNvariant-TIMEsformer-for-Video-Deepfake-Detection.
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Prescriptive Process Monitoring systems recommend, during the execution of a business process, interventions that, if followed, prevent a negative outcome of the process. Such interventions have to be reliable, that is, they have to guarantee the achievement of the desired outcome or performance, and they have to be flexible, that is, they have to avoid overturning the normal process execution or forcing the execution of a given activity. Most of the existing Prescriptive Process Monitoring solutions, however, while performing well in terms of recommendation reliability, provide the users with very specific (sequences of) activities that have to be executed without caring about the feasibility of these recommendations. In order to face this issue, we propose a new Outcome-Oriented Prescriptive Process Monitoring system recommending temporal relations between activities that have to be guaranteed during the process execution in order to achieve a desired outcome. This softens the mandatory execution of an activity at a given point in time, thus leaving more freedom to the user in deciding the interventions to put in place. Our approach defines these temporal relations with Linear Temporal Logic over finite traces patterns that are used as features to describe the historical process data recorded in an event log by the information systems supporting the execution of the process. Such encoded log is used to train a Machine Learning classifier to learn a mapping between the temporal patterns and the outcome of a process execution. The classifier is then queried at runtime to return as recommendations the most salient temporal patterns to be satisfied to maximize the likelihood of a certain outcome for an input ongoing process execution. The proposed system is assessed using a pool of 22 real-life event logs that have already been used as a benchmark in the Process Mining community.
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事实证明,图形神经网络(GNN)在图形结构数据的几个预测建模任务中已被证明。在这些任务中,链接预测是许多现实世界应用(例如推荐系统)的基本问题之一。但是,GNN不能免疫对抗攻击,即精心制作的恶意例子,旨在欺骗预测模型。在这项工作中,我们专注于对基于GNN的链接预测模型进行特定的白盒攻击,其中恶意节点的目的是出现在给定目标受害者的推荐节点列表中。为了实现这一目标,攻击者节点还可以指望它直接控制的其他现有同伴的合作,即在网络中注入许多``vicious''节点的能力。具体而言,所有这些恶意节点都可以添加新的边缘或删除现有的节点,从而扰乱原始图。因此,我们提出了野蛮人,一种新颖的框架和一种安装这种链接预测攻击的方法。野蛮人将对手的目标制定为一项优化任务,从而达到了攻击的有效性与所需的恶意资源的稀疏之间的平衡。在现实世界和合成数据集上进行的广泛实验表明,通过野蛮人实施的对抗性攻击确实达到了很高的攻击成功率,但使用少量恶性节点。最后,尽管这些攻击需要完全了解目标模型,但我们表明它们可以成功地转移到其他黑框方法以进行链接预测。
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许多涉及某种形式的3D视觉感知的机器人任务极大地受益于对工作环境的完整知识。但是,机器人通常必须应对非结构化的环境,并且由于工作空间有限,混乱或对象自我划分,它们的车载视觉传感器只能提供不完整的信息。近年来,深度学习架构的形状完成架构已开始将牵引力作为从部分视觉数据中推断出完整的3D对象表示的有效手段。然而,大多数现有的最新方法都以体素电网形式提供了固定的输出分辨率,这与神经网络输出阶段的大小严格相关。尽管这足以完成某些任务,例如导航,抓握和操纵的障碍需要更精细的分辨率,并且简单地扩大神经网络输出在计算上是昂贵的。在本文中,我们通过基于隐式3D表示的对象形状完成方法来解决此限制,该方法为每个重建点提供了置信值。作为第二个贡献,我们提出了一种基于梯度的方法,用于在推理时在任意分辨率下有效地采样这种隐式函数。我们通过将重建的形状与地面真理进行比较,并通过在机器人握把管道中部署形状完成算法来实验验证我们的方法。在这两种情况下,我们将结果与最先进的形状完成方法进行了比较。
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由于监视摄像头网络的无处不在,从图像中计算的自动人士最近引起了现代智能城市的城市监测的注意。当前的计算机视觉技术依赖于基于深度学习的算法,这些算法估算了静止图像中的行人密度。只有一堆作品利用视频序列中的时间一致性。在这项工作中,我们提出了一个时空的细心神经网络,以估计监视视频中的行人数量。通过利用连续帧之间的时间相关性,我们在广泛使用的FDST基准上将最新的计数误差降低了5%,定位误差降低了7.5%。
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在由家用电器,电动汽车和太阳能电池板等各种设备组成的分散家庭能源系统中,最终用户可以更深入地研究该系统的细节,并进一步实现能源可持续性,如果向它们提供了有关电能消耗的数据和设备粒度的生产。但是,该领域中的许多数据库都是从其他域中孤立的,包括仅与能源有关的信息。这可能会导致每个设备能源使用的信息损失(\ textit {例如{例如}天气)。同时,许多这些数据集已在计算建模技术(例如机器学习模型)中广泛使用。尽管这种计算方法仅通过仅专注于数据集的局部视图来实现极高的准确性和性能,但不能保证模型可靠性,因为当考虑到信息遗漏时,此类模型非常容易受到数据输入波动的影响。本文通过在家庭能源系统的基础上检查语义Web方法来解决智能能源系统领域的数据隔离问题。我们提供了一种基于本体的方法,用于在系统中的设备级分辨率下管理分散数据。结果,与每个设备相关的数据的范围可以在整个网络中以可互操作的方式轻松扩展,并且只要根据W3C标准组织数据,就可以从网络中获得其他信息,例如天气。 。
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