我们考虑了分布式随机优化问题,其中$ n $代理想要最大程度地减少代理本地函数总和给出的全局函数,并专注于当代理的局部函数在非i.i.i.d上定义时,专注于异质设置。数据集。我们研究本地SGD方法,在该方法中,代理执行许多局部随机梯度步骤,并偶尔与中央节点进行通信以改善其本地优化任务。我们分析了本地步骤对局部SGD的收敛速率和通信复杂性的影响。特别是,我们允许在$ i $ th的通信回合($ h_i $)期间允许在所有通信回合中进行固定数量的本地步骤。我们的主要贡献是将本地SGD的收敛速率表征为$ \ {h_i \} _ {i = 1}^r $在强烈凸,convex和nonconvex local函数下的函数,其中$ r $是沟通总数。基于此特征,我们在序列$ \ {h_i \} _ {i = 1}^r $上提供足够的条件,使得本地SGD可以相对于工人数量实现线性加速。此外,我们提出了一种新的沟通策略,将本地步骤提高,优于现有的沟通策略,以突出局部功能。另一方面,对于凸和非凸局局功能,我们认为固定的本地步骤是本地SGD的最佳通信策略,并恢复了最新的收敛速率结果。最后,我们通过广泛的数值实验证明我们的理论结果是合理的。
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我们考虑了一个$ n $ - 玩家随机游戏的子类,其中玩家在通过收益功能耦合时拥有自己的内部状态/动作空间。假定玩家的内部链是由独立过渡概率驱动的。此外,玩家只能收到其回报的实现,而不是实际功能,并且无法观察彼此的状态/行动。根据一些关于收益功能结构的假设,我们基于双重平均和双镜下降开发有效的学习算法,该算法几乎可以肯定地融合或预期$ \ epsilon $ nash $ nash平衡策略。特别是,我们根据游戏参数的多项式划分的迭代数量得出了上限,以实现$ \ epsilon $ -NASH平衡策略。除了马尔可夫潜在的游戏和线性季节随机游戏外,这项工作还提供了$ n $ - 玩家随机游戏的另一个子类,这些游戏可证明可以允许多项式学习算法找到其$ \ epsilon $ nash平衡策略。
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我们考虑一个动态上校的Blotto游戏(CBG),其中一个玩家是学习者,并且有限的部队(预算)在有限的时间范围内分配。在每个阶段,学习者策略性地根据过去的观察确定战地中的预算分布。另一个玩家是对手,他们从一些固定的未知分发中随机选择预算分配策略。学习者的目标是最大限度地减少其遗憾,这是通过遵循学习算法的最佳混合策略的收益和实现的收益之间的差异。在组合强盗和带背包的骨架的框架下分析动态CBG。首先将动态CBG与预算约束转换为图表上的路径规划问题。然后,我们为学习者设计了一个有效的动态策略,用于在路径规划图上使用组合强盗算法边缘作为另一算法Lagrangebwk的子程序。结果表明,在拟议的政策下,学习者的遗憾是在时间上限的术语中的临时概要,以时间为地平线$ T $和多项式相对于其他参数。
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Designing experiments often requires balancing between learning about the true treatment effects and earning from allocating more samples to the superior treatment. While optimal algorithms for the Multi-Armed Bandit Problem (MABP) provide allocation policies that optimally balance learning and earning, they tend to be computationally expensive. The Gittins Index (GI) is a solution to the MABP that can simultaneously attain optimality and computationally efficiency goals, and it has been recently used in experiments with Bernoulli and Gaussian rewards. For the first time, we present a modification of the GI rule that can be used in experiments with exponentially-distributed rewards. We report its performance in simulated 2- armed and 3-armed experiments. Compared to traditional non-adaptive designs, our novel GI modified design shows operating characteristics comparable in learning (e.g. statistical power) but substantially better in earning (e.g. direct benefits). This illustrates the potential that designs using a GI approach to allocate participants have to improve participant benefits, increase efficiencies, and reduce experimental costs in adaptive multi-armed experiments with exponential rewards.
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Quadruped robots are currently used in industrial robotics as mechanical aid to automate several routine tasks. However, presently, the usage of such a robot in a domestic setting is still very much a part of the research. This paper discusses the understanding and virtual simulation of such a robot capable of detecting and understanding human emotions, generating its gait, and responding via sounds and expression on a screen. To this end, we use a combination of reinforcement learning and software engineering concepts to simulate a quadruped robot that can understand emotions, navigate through various terrains and detect sound sources, and respond to emotions using audio-visual feedback. This paper aims to establish the framework of simulating a quadruped robot that is emotionally intelligent and can primarily respond to audio-visual stimuli using motor or audio response. The emotion detection from the speech was not as performant as ERANNs or Zeta Policy learning, still managing an accuracy of 63.5%. The video emotion detection system produced results that are almost at par with the state of the art, with an accuracy of 99.66%. Due to its "on-policy" learning process, the PPO algorithm was extremely rapid to learn, allowing the simulated dog to demonstrate a remarkably seamless gait across the different cadences and variations. This enabled the quadruped robot to respond to generated stimuli, allowing us to conclude that it functions as predicted and satisfies the aim of this work.
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Real-world robotic grasping can be done robustly if a complete 3D Point Cloud Data (PCD) of an object is available. However, in practice, PCDs are often incomplete when objects are viewed from few and sparse viewpoints before the grasping action, leading to the generation of wrong or inaccurate grasp poses. We propose a novel grasping strategy, named 3DSGrasp, that predicts the missing geometry from the partial PCD to produce reliable grasp poses. Our proposed PCD completion network is a Transformer-based encoder-decoder network with an Offset-Attention layer. Our network is inherently invariant to the object pose and point's permutation, which generates PCDs that are geometrically consistent and completed properly. Experiments on a wide range of partial PCD show that 3DSGrasp outperforms the best state-of-the-art method on PCD completion tasks and largely improves the grasping success rate in real-world scenarios. The code and dataset will be made available upon acceptance.
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When robots learn reward functions using high capacity models that take raw state directly as input, they need to both learn a representation for what matters in the task -- the task ``features" -- as well as how to combine these features into a single objective. If they try to do both at once from input designed to teach the full reward function, it is easy to end up with a representation that contains spurious correlations in the data, which fails to generalize to new settings. Instead, our ultimate goal is to enable robots to identify and isolate the causal features that people actually care about and use when they represent states and behavior. Our idea is that we can tune into this representation by asking users what behaviors they consider similar: behaviors will be similar if the features that matter are similar, even if low-level behavior is different; conversely, behaviors will be different if even one of the features that matter differs. This, in turn, is what enables the robot to disambiguate between what needs to go into the representation versus what is spurious, as well as what aspects of behavior can be compressed together versus not. The notion of learning representations based on similarity has a nice parallel in contrastive learning, a self-supervised representation learning technique that maps visually similar data points to similar embeddings, where similarity is defined by a designer through data augmentation heuristics. By contrast, in order to learn the representations that people use, so we can learn their preferences and objectives, we use their definition of similarity. In simulation as well as in a user study, we show that learning through such similarity queries leads to representations that, while far from perfect, are indeed more generalizable than self-supervised and task-input alternatives.
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and widely used information measurement metric, particularly popularized for SSVEP- based Brain-Computer (BCI) interfaces. By combining speed and accuracy into a single-valued parameter, this metric aids in the evaluation and comparison of various target identification algorithms across different BCI communities. To accurately depict performance and inspire an end-to-end design for futuristic BCI designs, a more thorough examination and definition of ITR is therefore required. We model the symbiotic communication medium, hosted by the retinogeniculate visual pathway, as a discrete memoryless channel and use the modified capacity expressions to redefine the ITR. We use graph theory to characterize the relationship between the asymmetry of the transition statistics and the ITR gain with the new definition, leading to potential bounds on data rate performance. On two well-known SSVEP datasets, we compared two cutting-edge target identification methods. Results indicate that the induced DM channel asymmetry has a greater impact on the actual perceived ITR than the change in input distribution. Moreover, it is demonstrated that the ITR gain under the new definition is inversely correlated with the asymmetry in the channel transition statistics. Individual input customizations are further shown to yield perceived ITR performance improvements. An algorithm is proposed to find the capacity of binary classification and further discussions are given to extend such results to ensemble techniques.We anticipate that the results of our study will contribute to the characterization of the highly dynamic BCI channel capacities, performance thresholds, and improved BCI stimulus designs for a tighter symbiosis between the human brain and computer systems while enhancing the efficiency of the underlying communication resources.
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A step-search sequential quadratic programming method is proposed for solving nonlinear equality constrained stochastic optimization problems. It is assumed that constraint function values and derivatives are available, but only stochastic approximations of the objective function and its associated derivatives can be computed via inexact probabilistic zeroth- and first-order oracles. Under reasonable assumptions, a high-probability bound on the iteration complexity of the algorithm to approximate first-order stationarity is derived. Numerical results on standard nonlinear optimization test problems illustrate the advantages and limitations of our proposed method.
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Differentiable Architecture Search (DARTS) has attracted considerable attention as a gradient-based Neural Architecture Search (NAS) method. Since the introduction of DARTS, there has been little work done on adapting the action space based on state-of-art architecture design principles for CNNs. In this work, we aim to address this gap by incrementally augmenting the DARTS search space with micro-design changes inspired by ConvNeXt and studying the trade-off between accuracy, evaluation layer count, and computational cost. To this end, we introduce the Pseudo-Inverted Bottleneck conv block intending to reduce the computational footprint of the inverted bottleneck block proposed in ConvNeXt. Our proposed architecture is much less sensitive to evaluation layer count and outperforms a DARTS network with similar size significantly, at layer counts as small as 2. Furthermore, with less layers, not only does it achieve higher accuracy with lower GMACs and parameter count, GradCAM comparisons show that our network is able to better detect distinctive features of target objects compared to DARTS.
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