为了追踪和运动捕获(MOCAP)在其自然栖息地中的动物,非常适合安全和无声的空中平台,例如带有车载摄像机的飞艇。但是,与多旋转器不同,飞艇受到严格的运动限制和受环境风的影响。它们的方向和飞行方向也紧密耦合。因此,用于感知任务的基于最新的MPC的形成控制方法不适用于飞艇团队。在本文中,我们首先利用飞艇的空速与其与主题的距离之间的定期关系来解决这个问题。我们使用它来得出满足MOCAP感知约束的分析和数字解决方案。基于此,我们开发了一个基于MPC的编队控制器。我们对解决方案进行了详细的分析,包括改变物理参数(例如攻击角度和俯仰角)的影响。提出了广泛的仿真实验,比较了不同的形成大小,不同的风条件和各种受试者速度的结果。还包括我们关于真实飞艇的方法的演示。我们已经在https://github.com/robot-pocepepon-group/airship-mpc上发布了所有源代码。可以在https://youtu.be/ihs0_vrd_kk上观看描述我们方法和结果的视频。
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我们探索稀疏优化问题的算法和局限性,例如稀疏线性回归和稳健的线性回归。稀疏线性回归问题的目的是确定少数关键特征,而强大的线性回归问题的目标是确定少量错误的测量值。具体而言,稀疏线性回归问题寻求$ k $ -sparse vector $ x \ in \ mathbb {r}^d $以最小化$ \ | ax-b \ | _2 $,给定输入矩阵$ a \ in \ mathbb in \ mathbb {r}^{n \ times d} $和一个目标向量$ b \ in \ mathbb {r}^n $,而强大的线性回归问题寻求一个$ s $ s $,最多可以忽略$ k $行和a向量$ x $最小化$ \ |(ax-b)_s \ | _2 $。我们首先显示了在[OWZ15]工作上稳健回归构建的近似近似值的双晶格,这意味着稀疏回归的结果相似。我们通过减少$ k $ clique的猜想,进一步显示出稳健回归的精细颗粒硬度。在正面,我们给出了一种鲁棒回归的算法,该算法可实现任意准确的添加误差,并使用运行时与从细粒硬度结果中的下界紧密匹配的运行时,以及与类似运行时稀疏回归的算法。我们的上限和下限都依赖于从鲁棒线性回归到我们引入的稀疏回归的一般减少。我们的算法受到3SUM问题的启发,使用大约最近的邻居数据结构,并且可能具有独立的兴趣来解决稀疏优化问题。例如,我们证明我们的技术也可以用于研究稀疏的PCA问题。
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统一测试是财产测试中最有研究的问题之一,其中许多已知的测试统计数据,包括基于计数碰撞,单例和经验电视距离的统计数据。众所周知,以$ 1- \ delta $概率为$ n = \ theta \ left(\ frac {\ sqrt {m {m {m) \ log(1/\ delta)}}} {\ epsilon^2} + \ frac {\ log(1/\ delta)} {\ epsilon^2} \ right)$,这是由经验性的电视测试器实现的。然而,在模拟中,这些理论分析具有误导性:在许多情况下,即使在所有参数的渐近制度中,它们也无法正确排序现有测试人员的性能,即$ 0 $或$ \ infty $。我们通过研究算法所需的\ emph {常数因子}来解释这一差异。我们表明,碰撞测试仪在均匀输入和非均匀输入之间的分离偏差数量中达到了急剧的最大常数。然后,我们根据Huber损失介绍了一个新的测试仪,并表明它不仅与此分离相匹配,而且还具有与该分离的高斯相对应的尾巴。这导致样本复杂性为$(1 + o(1))\ frac {\ sqrt {m \ log(1/\ delta)}}} {\ epsilon^2} $在该术语中,在此术语中,与此术语为主导所有其他现有测试人员。
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我们考虑一维位置估计,其中我们从$ n $ samples $ \ lambda + \ eta_i $估算一个参数$ \ lambda $,每个$ \ eta_i $ drawn i.i.d.从已知的分销$ f $。对于固定的$ f $,最大易变估计(MLE)众所周知,在$ n \ to \ infty $中是最佳的,它是渐近正常的,差异与cram \'er-rao的差异相匹配。\ frac {1} {n \ Mathcal {i}} $,其中$ \ Mathcal {i} $是$ f $的Fisher信息。但是,这种界限不适合有限$ n $,或者当$ f $随$ n $而变化时。我们以任意$ f $和$ n $的方式显示,人们可以根据$ f $的平滑版本的渔民信息来恢复类似的理论,其中平滑半径损失了$ n $。
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CSGM框架(Bora-Jalal-Price-Dimakis'17)表明,深度生成前沿可能是解决逆问题的强大工具。但是,迄今为止,此框架仅在某些数据集(例如,人称和MNIST数字)上经验成功,并且已知在分布外样品上表现不佳。本文介绍了CSGM框架在临床MRI数据上的第一次成功应用。我们在FastMri DataSet上培训了大脑扫描之前的生成,并显示通过Langevin Dynamics的后验采样实现了高质量的重建。此外,我们的实验和理论表明,后部采样是对地面定语分布和测量过程的变化的强大。我们的代码和型号可用于:\ URL {https://github.com/utcsilab/csgm-mri-langevin}。
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我们提出了两种线性土匪算法,具有每步复杂性sublerear的武器$ k $。该算法专为手臂集非常大且缓慢变化的应用而设计。我们的关键意识到,选择手臂还原为最大的内部产品搜索(MIPS)问题,该问题可以大约解决,而无需打破后悔保证。现有的近似MIPS求解器以均匀时间运行。我们扩展了这些求解器,并为在线学习问题提供理论保证,在线学习问题(即,以后的步骤取决于上一步中的反馈)成为一个独特的挑战。然后,我们明确表征了每步复杂性与遗憾之间的权衡。对于足够大的$ k $,我们的算法具有sublinear每步复杂性和$ \ tilde o(\ sqrt {t})$遗憾。从经验上讲,我们在合成环境和现实世界中的电影推荐问题中评估了我们提出的算法。与线性时间基线相比,我们提出的算法可以提供超过72倍的速度,同时保留了类似的遗憾。
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The goal of compressed sensing is to estimate a vector from an underdetermined system of noisy linear measurements, by making use of prior knowledge on the structure of vectors in the relevant domain. For almost all results in this literature, the structure is represented by sparsity in a well-chosen basis. We show how to achieve guarantees similar to standard compressed sensing but without employing sparsity at all. Instead, we suppose that vectors lie near the range of a generative model G : R k → R n . Our main theorem is that, if G is L-Lipschitz, then roughly O(k log L) random Gaussian measurements suffice for an 2/ 2 recovery guarantee. We demonstrate our results using generative models from published variational autoencoder and generative adversarial networks. Our method can use 5-10x fewer measurements than Lasso for the same accuracy.
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We propose a criterion for discrimination against a specified sensitive attribute in supervised learning, where the goal is to predict some target based on available features. Assuming data about the predictor, target, and membership in the protected group are available, we show how to optimally adjust any learned predictor so as to remove discrimination according to our definition. Our framework also improves incentives by shifting the cost of poor classification from disadvantaged groups to the decision maker, who can respond by improving the classification accuracy.In line with other studies, our notion is oblivious: it depends only on the joint statistics of the predictor, the target and the protected attribute, but not on interpretation of individual features. We study the inherent limits of defining and identifying biases based on such oblivious measures, outlining what can and cannot be inferred from different oblivious tests.We illustrate our notion using a case study of FICO credit scores.
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Non-linear state-space models, also known as general hidden Markov models, are ubiquitous in statistical machine learning, being the most classical generative models for serial data and sequences in general. The particle-based, rapid incremental smoother PaRIS is a sequential Monte Carlo (SMC) technique allowing for efficient online approximation of expectations of additive functionals under the smoothing distribution in these models. Such expectations appear naturally in several learning contexts, such as likelihood estimation (MLE) and Markov score climbing (MSC). PARIS has linear computational complexity, limited memory requirements and comes with non-asymptotic bounds, convergence results and stability guarantees. Still, being based on self-normalised importance sampling, the PaRIS estimator is biased. Our first contribution is to design a novel additive smoothing algorithm, the Parisian particle Gibbs PPG sampler, which can be viewed as a PaRIS algorithm driven by conditional SMC moves, resulting in bias-reduced estimates of the targeted quantities. We substantiate the PPG algorithm with theoretical results, including new bounds on bias and variance as well as deviation inequalities. Our second contribution is to apply PPG in a learning framework, covering MLE and MSC as special examples. In this context, we establish, under standard assumptions, non-asymptotic bounds highlighting the value of bias reduction and the implicit Rao--Blackwellization of PPG. These are the first non-asymptotic results of this kind in this setting. We illustrate our theoretical results with numerical experiments supporting our claims.
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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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