事件摄像机是受到生物启发的视觉传感器,异步代表像素级亮度随着事件流而变化。基于事件的单眼多视图立体声(EMV)是一种利用事件流以估算具有已知轨迹的半密度3D结构的技术。对于基于事件的单眼大满贯,这是一项关键任务。但是,所需的密集计算工作负载使其对于嵌入式平台上的实时部署而具有挑战性。在本文中,通过实现最关键和最耗时的阶段,包括事件反向预测和FPGA上的体积射线计数,提出Eventor作为快速有效的EMV加速器。高度平行且完全管道的处理元素是通过FPGA专门设计的,并与嵌入式臂集成为异质系统,以改善吞吐量并减少记忆足迹。同时,通过重新安排,近似计算和混合数据量化,将EMVS算法重新制定为更硬件的方式。戴维斯数据集的评估结果表明,与英特尔i5 CPU平台相比,Eventor的能源效率最高可提高$ 24 \ times $。
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跨域建议可以帮助缓解传统的连续推荐系统中的数据稀疏问题。在本文中,我们提出了Recguru算法框架,以在顺序推荐中生成包含跨域的用户信息的广义用户表示,即使在两个域中的最小或没有公共用户时也是如此。我们提出了一种自我细心的AutoEncoder来导出潜在用户表示,以及域鉴别器,其旨在预测所产生的潜在表示的原点域。我们提出了一种新的逆势学习方法来训练两个模块,以使从不同域生成的用户嵌入到每个用户的单个全局Gur。学习的Gur捕获了用户的整体偏好和特征,因此可以用于增强行为数据并改进在涉及用户的任何单个域中的推荐。在两个公共交叉域推荐数据集以及从现实世界应用程序收集的大型数据集进行了广泛的实验。结果表明,Recguru提高了性能,优于各种最先进的顺序推荐和跨域推荐方法。收集的数据将被释放以促进未来的研究。
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联合学习(FL)是一种分布式机器学习方法,其中多个客户在不交换数据的情况下协作培训联合模型。尽管FL在数据隐私保护方面取得了前所未有的成功,但其对自由骑手攻击的脆弱性吸引了人们越来越多的关注。现有的防御能力可能对高度伪装或高百分比的自由骑手无效。为了应对这些挑战,我们从新颖的角度重新考虑防御,即模型重量不断发展的频率。从经验上讲,我们获得了一种新颖的见解,即在FL的训练中,模型权重的频率不断发展,自由骑机的频率和良性客户的频率显着不同的。受到这种见解的启发,我们提出了一种基于模型权重演化频率的新型防御方法,称为WEF-DEFENSE。特别是,我们在本地训练期间首先收集重量演变的频率(定义为WEF-MATRIX)。对于每个客户端,它将本地型号的WEF-Matrix与每个迭代的模型重量一起上传到服务器。然后,服务器根据WEF-Matrix的差异将自由骑士与良性客户端分开。最后,服务器使用个性化方法为相应的客户提供不同的全局模型。在五个数据集和五个模型上进行的全面实验表明,与最先进的基线相比,WEF防御能力更好。
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近年来,图像分类器的BlackBox传输攻击已被广泛研究。相比之下,对对象探测器的转移攻击取得了很小的进展。对象探测器采用图像的整体视图,并检测一个对象(或缺乏)通常取决于场景中的其他对象。这使得这种探测器本质上的上下文感知和对抗的攻击比目标图像分类器更具挑战性。在本文中,我们提出了一种新的方法来为对象检测器生成上下文感知攻击。我们表明,通过使用对象及其相关位置的共同发生和尺寸作为上下文信息,我们可以成功地生成目标的错误分类攻击,该攻击比最先进的Blackbox对象探测器上实现更高的转移成功率。我们在帕斯卡VOC和MS Coco Datasets的各种对象探测器上测试我们的方法,与其他最先进的方法相比,性能提高了高达20美元的百分点。
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因果推断是在采用干预时估计因果关系中的因果效应。确切地说,在具有二进制干预措施的因果模型中,即控制和治疗,因果效应仅仅是事实和反事实之间的差异。困难是必须估算反事实,因此因果效应只能是估计。估计反事实的主要挑战是确定影响结果和治疗的混杂因素。一种典型的方法是将因果推论作为监督学习问题,因此可以预测反事实。包括线性回归和深度学习模型,最近的机器学习方法已适应因果推断。在本文中,我们提出了一种通过使用变分信息瓶颈(CEVIB)来估计因果效应的方法。有希望的点是,VIB能够自然地将变量从数据中蒸馏出来,从而可以通过使用观察数据来估计因果效应。我们通过将CEVIB应用于三个数据集,表明我们的方法实现了最佳性能,将其应用于其他方法。我们还实验表明了我们方法的鲁棒性。
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Compressed videos often exhibit visually annoying artifacts, known as Perceivable Encoding Artifacts (PEAs), which dramatically degrade video visual quality. Subjective and objective measures capable of identifying and quantifying various types of PEAs are critical in improving visual quality. In this paper, we investigate the influence of four spatial PEAs (i.e. blurring, blocking, bleeding, and ringing) and two temporal PEAs (i.e. flickering and floating) on video quality. For spatial artifacts, we propose a visual saliency model with a low computational cost and higher consistency with human visual perception. In terms of temporal artifacts, self-attention based TimeSFormer is improved to detect temporal artifacts. Based on the six types of PEAs, a quality metric called Saliency-Aware Spatio-Temporal Artifacts Measurement (SSTAM) is proposed. Experimental results demonstrate that the proposed method outperforms state-of-the-art metrics. We believe that SSTAM will be beneficial for optimizing video coding techniques.
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As one of the most important psychic stress reactions, micro-expressions (MEs), are spontaneous and transient facial expressions that can reveal the genuine emotions of human beings. Thus, recognizing MEs (MER) automatically is becoming increasingly crucial in the field of affective computing, and provides essential technical support in lie detection, psychological analysis and other areas. However, the lack of abundant ME data seriously restricts the development of cutting-edge data-driven MER models. Despite the recent efforts of several spontaneous ME datasets to alleviate this problem, it is still a tiny amount of work. To solve the problem of ME data hunger, we construct a dynamic spontaneous ME dataset with the largest current ME data scale, called DFME (Dynamic Facial Micro-expressions), which includes 7,526 well-labeled ME videos induced by 671 participants and annotated by more than 20 annotators throughout three years. Afterwards, we adopt four classical spatiotemporal feature learning models on DFME to perform MER experiments to objectively verify the validity of DFME dataset. In addition, we explore different solutions to the class imbalance and key-frame sequence sampling problems in dynamic MER respectively on DFME, so as to provide a valuable reference for future research. The comprehensive experimental results show that our DFME dataset can facilitate the research of automatic MER, and provide a new benchmark for MER. DFME will be published via https://mea-lab-421.github.io.
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Face Anti-spoofing (FAS) is essential to secure face recognition systems from various physical attacks. However, recent research generally focuses on short-distance applications (i.e., phone unlocking) while lacking consideration of long-distance scenes (i.e., surveillance security checks). In order to promote relevant research and fill this gap in the community, we collect a large-scale Surveillance High-Fidelity Mask (SuHiFiMask) dataset captured under 40 surveillance scenes, which has 101 subjects from different age groups with 232 3D attacks (high-fidelity masks), 200 2D attacks (posters, portraits, and screens), and 2 adversarial attacks. In this scene, low image resolution and noise interference are new challenges faced in surveillance FAS. Together with the SuHiFiMask dataset, we propose a Contrastive Quality-Invariance Learning (CQIL) network to alleviate the performance degradation caused by image quality from three aspects: (1) An Image Quality Variable module (IQV) is introduced to recover image information associated with discrimination by combining the super-resolution network. (2) Using generated sample pairs to simulate quality variance distributions to help contrastive learning strategies obtain robust feature representation under quality variation. (3) A Separate Quality Network (SQN) is designed to learn discriminative features independent of image quality. Finally, a large number of experiments verify the quality of the SuHiFiMask dataset and the superiority of the proposed CQIL.
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Interview has been regarded as one of the most crucial step for recruitment. To fully prepare for the interview with the recruiters, job seekers usually practice with mock interviews between each other. However, such a mock interview with peers is generally far away from the real interview experience: the mock interviewers are not guaranteed to be professional and are not likely to behave like a real interviewer. Due to the rapid growth of online recruitment in recent years, recruiters tend to have online interviews, which makes it possible to collect real interview data from real interviewers. In this paper, we propose a novel application named EZInterviewer, which aims to learn from the online interview data and provides mock interview services to the job seekers. The task is challenging in two ways: (1) the interview data are now available but still of low-resource; (2) to generate meaningful and relevant interview dialogs requires thorough understanding of both resumes and job descriptions. To address the low-resource challenge, EZInterviewer is trained on a very small set of interview dialogs. The key idea is to reduce the number of parameters that rely on interview dialogs by disentangling the knowledge selector and dialog generator so that most parameters can be trained with ungrounded dialogs as well as the resume data that are not low-resource. Evaluation results on a real-world job interview dialog dataset indicate that we achieve promising results to generate mock interviews. With the help of EZInterviewer, we hope to make mock interview practice become easier for job seekers.
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Nowadays, time-stamped web documents related to a general news query floods spread throughout the Internet, and timeline summarization targets concisely summarizing the evolution trajectory of events along the timeline. Unlike traditional document summarization, timeline summarization needs to model the time series information of the input events and summarize important events in chronological order. To tackle this challenge, in this paper, we propose a Unified Timeline Summarizer (UTS) that can generate abstractive and extractive timeline summaries in time order. Concretely, in the encoder part, we propose a graph-based event encoder that relates multiple events according to their content dependency and learns a global representation of each event. In the decoder part, to ensure the chronological order of the abstractive summary, we propose to extract the feature of event-level attention in its generation process with sequential information remained and use it to simulate the evolutionary attention of the ground truth summary. The event-level attention can also be used to assist in extracting summary, where the extracted summary also comes in time sequence. We augment the previous Chinese large-scale timeline summarization dataset and collect a new English timeline dataset. Extensive experiments conducted on these datasets and on the out-of-domain Timeline 17 dataset show that UTS achieves state-of-the-art performance in terms of both automatic and human evaluations.
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