深度卷积神经网络(DCNNS)在面部识别方面已经达到了人类水平的准确性(Phillips等,2018),尽管目前尚不清楚它们如何准确地区分高度相似的面孔。在这里,人类和DCNN执行了包括相同双胞胎在内的具有挑战性的面貌匹配任务。参与者(n = 87)查看了三种类型的面孔图像:同一身份,普通冒名顶替对(来自相似人口组的不同身份)和双胞胎冒名顶替对(相同的双胞胎兄弟姐妹)。任务是确定对是同一个人还是不同的人。身份比较在三个观点区分条件下进行了测试:额叶至额叶,额叶至45度,额叶为90度。在每个观点 - 差异条件下评估了从双胞胎突变器和一般冒险者区分匹配的身份对的准确性。人类对于一般撞击对比双重射手对更准确,准确性下降,一对图像之间的观点差异增加。通过介绍给人类的同一图像对测试了经过训练的面部识别的DCNN(Ranjan等,2018)。机器性能反映了人类准确性的模式,但除了一种条件以外,所有人的性能都处于或尤其是所有人的表现。在所有图像对类型中,比较了人与机器的相似性得分。该项目级别的分析表明,在九种图像对类型中的六种中,人类和机器的相似性等级显着相关[范围r = 0.38至r = 0.63],这表明人类对面部相似性的感知和DCNN之间的一般协议。这些发现还有助于我们理解DCNN的表现,以区分高度介绍面孔,表明DCNN在人类或以上的水平上表现出色,并暗示了人类和DCNN使用的特征之间的均等程度。
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面部识别水平的度量对于确保专业法医面部考官和其他在应用方案中执行面部识别任务的其他人的准确和一致的表现至关重要。当前的熟练度测试依赖于静态刺激项目的集合,因此不能多次有效地对同一个人进行有效管理。要创建熟练度测试,必须组装大量“已知”难度的项目。可以构建多个相等难度的测试,然后使用项目子集。我们介绍了三合会身份匹配(TIM)测试,并使用项目响应理论(IRT)对其进行评估。参与者查看面部图像“三合会”(n = 225)(一个身份的两个图像,一个不同身份的一个图像),然后选择不同的身份。在实验1中,大学生(n = 197)在TIM测试中显示出广泛的准确性,IRT建模表明TIM项目涵盖了各种难度水平。在实验2中,我们使用基于IRT的项目指标将测试分配为特定困难的子集。模拟显示,TIM项目的子集产生了对受试者能力的可靠估计。在实验3A和3B中,我们发现学生衍生的IRT模型可靠地评估了非学生参与者的能力以及在不同的测试课程中推广的能力。在实验3C中,我们显示TIM测试性能与其他常见的面部识别测试相关。总而言之,TIM测试为开发一个灵活和校准的框架提供了一个起点,以衡量各种能力水平(例如,具有面部处理缺陷的专业人员或人群)的能力。
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我们介绍了一种新颖的深度学习方法,用于使用高分辨率的多光谱空中图像在城市环境中检测单个树木。我们使用卷积神经网络来回归一个置信图,指示单个树的位置,该位置是使用峰查找算法本地化的。我们的方法通过检测公共和私人空间中的树木来提供完整的空间覆盖范围,并可以扩展到很大的区域。在我们的研究区域,跨越南加州的五个城市,我们的F评分为0.735,RMSE为2.157 m。我们使用我们的方法在加利福尼亚城市森林中生产所有树木的地图,这表明我们有可能在前所未有的尺度上支持未来的城市林业研究。
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While the capabilities of autonomous systems have been steadily improving in recent years, these systems still struggle to rapidly explore previously unknown environments without the aid of GPS-assisted navigation. The DARPA Subterranean (SubT) Challenge aimed to fast track the development of autonomous exploration systems by evaluating their performance in real-world underground search-and-rescue scenarios. Subterranean environments present a plethora of challenges for robotic systems, such as limited communications, complex topology, visually-degraded sensing, and harsh terrain. The presented solution enables long-term autonomy with minimal human supervision by combining a powerful and independent single-agent autonomy stack, with higher level mission management operating over a flexible mesh network. The autonomy suite deployed on quadruped and wheeled robots was fully independent, freeing the human supervision to loosely supervise the mission and make high-impact strategic decisions. We also discuss lessons learned from fielding our system at the SubT Final Event, relating to vehicle versatility, system adaptability, and re-configurable communications.
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Attention mechanisms form a core component of several successful deep learning architectures, and are based on one key idea: ''The output depends only on a small (but unknown) segment of the input.'' In several practical applications like image captioning and language translation, this is mostly true. In trained models with an attention mechanism, the outputs of an intermediate module that encodes the segment of input responsible for the output is often used as a way to peek into the `reasoning` of the network. We make such a notion more precise for a variant of the classification problem that we term selective dependence classification (SDC) when used with attention model architectures. Under such a setting, we demonstrate various error modes where an attention model can be accurate but fail to be interpretable, and show that such models do occur as a result of training. We illustrate various situations that can accentuate and mitigate this behaviour. Finally, we use our objective definition of interpretability for SDC tasks to evaluate a few attention model learning algorithms designed to encourage sparsity and demonstrate that these algorithms help improve interpretability.
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Recent advances in upper limb prostheses have led to significant improvements in the number of movements provided by the robotic limb. However, the method for controlling multiple degrees of freedom via user-generated signals remains challenging. To address this issue, various machine learning controllers have been developed to better predict movement intent. As these controllers become more intelligent and take on more autonomy in the system, the traditional approach of representing the human-machine interface as a human controlling a tool becomes limiting. One possible approach to improve the understanding of these interfaces is to model them as collaborative, multi-agent systems through the lens of joint action. The field of joint action has been commonly applied to two human partners who are trying to work jointly together to achieve a task, such as singing or moving a table together, by effecting coordinated change in their shared environment. In this work, we compare different prosthesis controllers (proportional electromyography with sequential switching, pattern recognition, and adaptive switching) in terms of how they present the hallmarks of joint action. The results of the comparison lead to a new perspective for understanding how existing myoelectric systems relate to each other, along with recommendations for how to improve these systems by increasing the collaborative communication between each partner.
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Recent advances in deep learning have enabled us to address the curse of dimensionality (COD) by solving problems in higher dimensions. A subset of such approaches of addressing the COD has led us to solving high-dimensional PDEs. This has resulted in opening doors to solving a variety of real-world problems ranging from mathematical finance to stochastic control for industrial applications. Although feasible, these deep learning methods are still constrained by training time and memory. Tackling these shortcomings, Tensor Neural Networks (TNN) demonstrate that they can provide significant parameter savings while attaining the same accuracy as compared to the classical Dense Neural Network (DNN). In addition, we also show how TNN can be trained faster than DNN for the same accuracy. Besides TNN, we also introduce Tensor Network Initializer (TNN Init), a weight initialization scheme that leads to faster convergence with smaller variance for an equivalent parameter count as compared to a DNN. We benchmark TNN and TNN Init by applying them to solve the parabolic PDE associated with the Heston model, which is widely used in financial pricing theory.
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Artificial neural networks can learn complex, salient data features to achieve a given task. On the opposite end of the spectrum, mathematically grounded methods such as topological data analysis allow users to design analysis pipelines fully aware of data constraints and symmetries. We introduce a class of persistence-based neural network layers. Persistence-based layers allow the users to easily inject knowledge about symmetries (equivariance) respected by the data, are equipped with learnable weights, and can be composed with state-of-the-art neural architectures.
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KL-regularized reinforcement learning from expert demonstrations has proved successful in improving the sample efficiency of deep reinforcement learning algorithms, allowing them to be applied to challenging physical real-world tasks. However, we show that KL-regularized reinforcement learning with behavioral reference policies derived from expert demonstrations can suffer from pathological training dynamics that can lead to slow, unstable, and suboptimal online learning. We show empirically that the pathology occurs for commonly chosen behavioral policy classes and demonstrate its impact on sample efficiency and online policy performance. Finally, we show that the pathology can be remedied by non-parametric behavioral reference policies and that this allows KL-regularized reinforcement learning to significantly outperform state-of-the-art approaches on a variety of challenging locomotion and dexterous hand manipulation tasks.
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Three main points: 1. Data Science (DS) will be increasingly important to heliophysics; 2. Methods of heliophysics science discovery will continually evolve, requiring the use of learning technologies [e.g., machine learning (ML)] that are applied rigorously and that are capable of supporting discovery; and 3. To grow with the pace of data, technology, and workforce changes, heliophysics requires a new approach to the representation of knowledge.
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