Machine learning techniques based on neural networks are achieving remarkable results in a wide variety of domains. Often, the training of models requires large, representative datasets, which may be crowdsourced and contain sensitive information. The models should not expose private information in these datasets. Addressing this goal, we develop new algorithmic techniques for learning and a refined analysis of privacy costs within the framework of differential privacy. Our implementation and experiments demonstrate that we can train deep neural networks with non-convex objectives, under a modest privacy budget, and at a manageable cost in software complexity, training efficiency, and model quality. * Google.† OpenAI. Work done while at Google.
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Content moderation is the process of screening and monitoring user-generated content online. It plays a crucial role in stopping content resulting from unacceptable behaviors such as hate speech, harassment, violence against specific groups, terrorism, racism, xenophobia, homophobia, or misogyny, to mention some few, in Online Social Platforms. These platforms make use of a plethora of tools to detect and manage malicious information; however, malicious actors also improve their skills, developing strategies to surpass these barriers and continuing to spread misleading information. Twisting and camouflaging keywords are among the most used techniques to evade platform content moderation systems. In response to this recent ongoing issue, this paper presents an innovative approach to address this linguistic trend in social networks through the simulation of different content evasion techniques and a multilingual Transformer model for content evasion detection. In this way, we share with the rest of the scientific community a multilingual public tool, named "pyleetspeak" to generate/simulate in a customizable way the phenomenon of content evasion through automatic word camouflage and a multilingual Named-Entity Recognition (NER) Transformer-based model tuned for its recognition and detection. The multilingual NER model is evaluated in different textual scenarios, detecting different types and mixtures of camouflage techniques, achieving an overall weighted F1 score of 0.8795. This article contributes significantly to countering malicious information by developing multilingual tools to simulate and detect new methods of evasion of content on social networks, making the fight against information disorders more effective.
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Social insects such as ants communicate via pheromones which allows them to coordinate their activity and solve complex tasks as a swarm, e.g. foraging for food. This behaviour was shaped through evolutionary processes. In computational models, self-coordination in swarms has been implemented using probabilistic or action rules to shape the decision of each agent and the collective behaviour. However, manual tuned decision rules may limit the behaviour of the swarm. In this work we investigate the emergence of self-coordination and communication in evolved swarms without defining any rule. We evolve a swarm of agents representing an ant colony. We use a genetic algorithm to optimize a spiking neural network (SNN) which serves as an artificial brain to control the behaviour of each agent. The goal of the colony is to find optimal ways to forage for food in the shortest amount of time. In the evolutionary phase, the ants are able to learn to collaborate by depositing pheromone near food piles and near the nest to guide its cohorts. The pheromone usage is not encoded into the network; instead, this behaviour is established through the optimization procedure. We observe that pheromone-based communication enables the ants to perform better in comparison to colonies where communication did not emerge. We assess the foraging performance by comparing the SNN based model to a rule based system. Our results show that the SNN based model can complete the foraging task more efficiently in a shorter time. Our approach illustrates that even in the absence of pre-defined rules, self coordination via pheromone emerges as a result of the network optimization. This work serves as a proof of concept for the possibility of creating complex applications utilizing SNNs as underlying architectures for multi-agent interactions where communication and self-coordination is desired.
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This project explores the feasibility of remote patient monitoring based on the analysis of 3D movements captured with smartwatches. We base our analysis on the Kinematic Theory of Rapid Human Movement. We have validated our research in a real case scenario for stroke rehabilitation at the Guttmann Institute5 (neurorehabilitation hospital), showing promising results. Our work could have a great impact in remote healthcare applications, improving the medical efficiency and reducing the healthcare costs. Future steps include more clinical validation, developing multi-modal analysis architectures (analysing data from sensors, images, audio, etc.), and exploring the application of our technology to monitor other neurodegenerative diseases.
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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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车载传感器的车载系统正在增强连接。这使信息共享能够实现对环境的更全面的理解。但是,通过公共蜂窝网络的同行通信带来了多个网络障碍以解决,需要网络系统来中继通信并连接无法直接连接的各方。 Web实时通信(WEBRTC)是跨车辆流媒体流媒体的良好候选者,因为它可以使延迟通信较低,同时将标准协议带到安全握手中,发现公共IP和横向网络地址转换(NAT)系统。但是,在基础架构中的端到端服务质量(QOS)适应,在该基础架构中,传输和接收是通过继电器解耦的,需要一种机制来有效地使视频流适应网络容量。为此,本文通过利用实时运输控制协议(RTCP)指标(例如带宽和往返时间)来调查解决分辨率,帧和比特率更改的机制。该解决方案旨在确保接收机上系统及时获得相关信息。在实际的5G测试台中分析了应用不同方法适应方法时对端到端吞吐量效率和反应时间的影响。
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我们提出了Vologan,这是一个对抗域的适应网络,该网络将一个人的高质量3D模型的合成RGB-D图像转换为可以使用消费者深度传感器生成的RGB-D图像。该系统对于为单视3D重建算法生成大量训练数据特别有用,该算法复制了现实世界中的捕获条件,能够模仿相同的高端3D模型数据库的不同传感器类型的样式。该网络使用具有u-net体系结构的CycleGAN框架,以及受SIV-GAN启发的鉴别器。我们使用不同的优化者和学习率计划来训练发电机和鉴别器。我们进一步构建了一个单独考虑图像通道的损失函数,除其他指标外,还评估了结构相似性。我们证明,可以使用自行车来应用合成3D数据的对抗结构域适应,以训练只有少量训练样本的体积视频发电机模型。
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由于需要快速原型制作和广泛的测试,模拟在自主驾驶中的作用变得越来越重要。基于物理的模拟使用涉及多个利益和优势,以合理的成本消除了对原型,驱动因素和脆弱道路使用者的风险。但是,有两个主要局限性。首先,众所周知的现实差距是指现实与模拟之间的差异,这阻止了模拟自主驾驶体验实现有效的现实性能。其次,缺乏有关真实代理商的行为的经验知识,包括备用驾驶员或乘客以及其他道路使用者,例如车辆,行人或骑自行车的人。代理仿真通常是根据实际数据进行确定性,随机概率或生成的预编程的,但它不代表与特定模拟方案相互作用的真实试剂的行为。在本文中,我们提出了一个初步框架,以实现真实试剂与模拟环境(包括自动驾驶汽车)之间的实时互动,并从多个视图中从模拟传感器数据中生成合成序列,这些视图可用于培训依赖行为模型的预测系统。我们的方法将沉浸式的虚拟现实和人类运动捕获系统与Carla模拟器进行自主驾驶。我们描述了提出的硬件和软件体系结构,并讨论所谓的行为差距或存在。我们提出了支持这种方法的潜力并讨论未来步骤的初步但有希望的结果。
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在过去的几年中,在深度学习中,在深度学习中广泛研究了域的概括问题,但对对比增强成像的关注受到了有限的关注。但是,临床中心之间的对比度成像方案存在明显差异,尤其是在对比度注入和图像采集之间,而与可用的非对抗成像的可用数据集相比,访问多中心对比度增强图像数据受到限制。这需要新的工具来概括单个中心的深度学习模型,跨越新的看不见的域和临床中心,以对比增强成像。在本文中,我们介绍了深度学习技术的详尽评估,以实现对对比度增强图像分割的看不见的临床中心的普遍性。为此,研究,优化和系统评估了几种技术,包括数据增强,域混合,转移学习和域的适应性。为了证明域泛化对对比增强成像的潜力,评估了对对比增强心脏磁共振成像(MRI)中的心室分割的方法。结果是根据位于三个国家(法国,西班牙和中国)的四家医院中获得的多中心心脏对比增强的MRI数据集获得的。他们表明,数据增强和转移学习的组合可以导致单中心模型,这些模型可以很好地推广到训练过程中未包括的新临床中心。在对比增强成像中,具有合适的概括程序的单域神经网络可以达到甚至超过多中心多供应商模型的性能,从而消除了对综合多中心数据集的需求,以训练可概括的模型。
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单光子敏感的深度传感器正在越来越多地用于人类姿势和手势识别的下一代电子。但是,具有成本效益的传感器通常具有低空间分辨率,从而将其用于基本运动识别和简单的对象检测。在这里,我们执行一个时间到空间映射,从而大大增加了简单飞行时间传感器的分辨率,即〜初始分辨率为4 $ \ times $ 4像素到分辨率32 $ \ times $ 32像素的深度图像。然后,可以将输出深度图用于准确的三维人姿势估计多人。我们开发了一个新的可解释框架,该框架为我们的网络如何利用其输入数据提供了直觉,并提供了有关相关参数的关键信息。我们的工作大大扩展了简单的飞机飞行时间传感器的用例,并为将来应用于具有相似数据类型的其他类型的传感器(即雷达和声纳)开辟了有希望的可能性。
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