医疗机器人技术可以帮助改善和扩大医疗服务的影响力。医疗机器人的一个主要挑战是机器人与患者之间的复杂物理相互作用是必须安全的。这项工作介绍了基于医疗应用中分形阻抗控制（FIC）的最近引入的控制体系结构的初步评估。部署的FIC体系结构在主机和复制机器人之间延迟很强。它可以在接纳和阻抗行为之间在线切换，并且与非结构化环境的互动是强大的。我们的实验分析了三种情况：远程手术，康复和远程超声扫描。实验不需要对机器人调整进行任何调整，这在操作员没有调整控制器所需的工程背景的医疗应用中至关重要。我们的结果表明，可以使用手术刀进行切割机器人，进行超声扫描并进行远程职业治疗。但是，我们的实验还强调了需要更好的机器人实施例，以精确控制3D动态任务中的系统。

需要强大的动态互动才能与人类一起在日常环境中移动机器人。优化和学习方法已用于模仿和再现人类运动。但是，它们通常不健壮，其概括是有限的。这项工作提出了用于机器人操纵器的层次控制体系结构，并提供了在未知相互作用动力学期间重现类似人类运动的功能。我们的结果表明，复制的最终效应轨迹可以保留通过运动捕获系统记录的初始人类运动的主要特征，并且对外部扰动具有鲁棒性。数据表明，由于硬件的物理限制无法达到人类运动中记录的相同速度，因此很难复制一些详细的运动。然而，可以通过使用更好的硬件来解决这些技术问题，我们提出的算法仍然可以应用于模仿动作。

由于事件的范围有限，在复杂且高度可变的环境中，避免路径计划和碰撞是具有挑战性的。在文献中，有多种基于模型和学习的方法需要有效地部署大量的计算资源，并且可能具有有限的一般性。我们提出了一种基于全球稳定的被动控制器的计划算法，该算法可以在挑战性的环境条件下使用有限的计算资源计划平滑轨迹。该体系结构将最近提出的分形阻抗控制器与有限时间不变性区域结合在一起。由于该方法基于阻抗控制器，因此它也可以直接用作力/扭矩控制器。我们在模拟中验证了我们的方法，以通过发放Via-toints的发行及其对低带宽反馈的稳健性来分析互动导航在挑战凹域中的能力。使用11个代理的群模拟验证了所提出方法的可扩展性。我们已经在自动式轮式平台上进行了硬件实验，以验证与动态剂（即人和机器人）相互作用的平滑度和稳健性。与依赖数字优化的其他方法相比，所提出的本地规划师的计算复杂性可以通过低功率微控制器的部署降低能源消耗。

机器人远程操作将使我们能够在危险或偏远的环境中执行复杂的操纵任务，例如行星勘探或核退役所需的。这项工作提出了使用被动分形阻抗控制器（FIC）的新型远程注射架构，该结构并不依赖于主动粘性组件以保证稳定性。与传统的阻抗控制器在理想条件下（无延迟和最大通信带宽）相比，我们提出的方法在交互作用方面产生了更高的透明度，并在我们的远程注射测试方案中证明了卓越的敏捷性和能力。我们还以高达1 s的极端延迟和通信带宽低至10 Hz的极端延迟来验证其性能。所有结果在具有挑战性的条件下使用拟议的控制器时，无论操作员的专业知识如何，所有结果都可以验证一致的稳定性。

对控制框架的兴趣越来越大，能够将机器人从工业笼子转移到非结构化环境并与人类共存。尽管某些特定应用（例如，医学机器人技术）有了显着改善，但仍然需要一个一般控制框架来改善鲁棒性和运动动力学。被动控制者在这个方向上显示出令人鼓舞的结果。但是，他们通常依靠虚拟能源储罐，只要它们不耗尽能量，就可以保证被动性。在本文中，提出了一个分形吸引子来实施可变的阻抗控制器，该控制器可以保留不依赖能箱的无源性。控制器使用渐近稳定电位场在所需状态周围生成一个分形吸引子，从而使控制器稳健地对离散化和数值集成误差。结果证明它可以在相互作用过程中准确跟踪轨迹和最终效应力。因此，这些属性使控制器非常适合需要在最终效应器上进行鲁棒动态相互作用的应用。

Computational units in artificial neural networks follow a simplified model of biological neurons. In the biological model, the output signal of a neuron runs down the axon, splits following the many branches at its end, and passes identically to all the downward neurons of the network. Each of the downward neurons will use their copy of this signal as one of many inputs dendrites, integrate them all and fire an output, if above some threshold. In the artificial neural network, this translates to the fact that the nonlinear filtering of the signal is performed in the upward neuron, meaning that in practice the same activation is shared between all the downward neurons that use that signal as their input. Dendrites thus play a passive role. We propose a slightly more complex model for the biological neuron, where dendrites play an active role: the activation in the output of the upward neuron becomes optional, and instead the signals going through each dendrite undergo independent nonlinear filterings, before the linear combination. We implement this new model into a ReLU computational unit and discuss its biological plausibility. We compare this new computational unit with the standard one and describe it from a geometrical point of view. We provide a Keras implementation of this unit into fully connected and convolutional layers and estimate their FLOPs and weights change. We then use these layers in ResNet architectures on CIFAR-10, CIFAR-100, Imagenette, and Imagewoof, obtaining performance improvements over standard ResNets up to 1.73%. Finally, we prove a universal representation theorem for continuous functions on compact sets and show that this new unit has more representational power than its standard counterpart.

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.

The visual dimension of cities has been a fundamental subject in urban studies, since the pioneering work of scholars such as Sitte, Lynch, Arnheim, and Jacobs. Several decades later, big data and artificial intelligence (AI) are revolutionizing how people move, sense, and interact with cities. This paper reviews the literature on the appearance and function of cities to illustrate how visual information has been used to understand them. A conceptual framework, Urban Visual Intelligence, is introduced to systematically elaborate on how new image data sources and AI techniques are reshaping the way researchers perceive and measure cities, enabling the study of the physical environment and its interactions with socioeconomic environments at various scales. The paper argues that these new approaches enable researchers to revisit the classic urban theories and themes, and potentially help cities create environments that are more in line with human behaviors and aspirations in the digital age.

General nonlinear sieve learnings are classes of nonlinear sieves that can approximate nonlinear functions of high dimensional variables much more flexibly than various linear sieves (or series). This paper considers general nonlinear sieve quasi-likelihood ratio (GN-QLR) based inference on expectation functionals of time series data, where the functionals of interest are based on some nonparametric function that satisfy conditional moment restrictions and are learned using multilayer neural networks. While the asymptotic normality of the estimated functionals depends on some unknown Riesz representer of the functional space, we show that the optimally weighted GN-QLR statistic is asymptotically Chi-square distributed, regardless whether the expectation functional is regular (root-$n$ estimable) or not. This holds when the data are weakly dependent beta-mixing condition. We apply our method to the off-policy evaluation in reinforcement learning, by formulating the Bellman equation into the conditional moment restriction framework, so that we can make inference about the state-specific value functional using the proposed GN-QLR method with time series data. In addition, estimating the averaged partial means and averaged partial derivatives of nonparametric instrumental variables and quantile IV models are also presented as leading examples. Finally, a Monte Carlo study shows the finite sample performance of the procedure

As various city agencies and mobility operators navigate toward innovative mobility solutions, there is a need for strategic flexibility in well-timed investment decisions in the design and timing of mobility service regions, i.e. cast as "real options" (RO). This problem becomes increasingly challenging with multiple interacting RO in such investments. We propose a scalable machine learning based RO framework for multi-period sequential service region design & timing problem for mobility-on-demand services, framed as a Markov decision process with non-stationary stochastic variables. A value function approximation policy from literature uses multi-option least squares Monte Carlo simulation to get a policy value for a set of interdependent investment decisions as deferral options (CR policy). The goal is to determine the optimal selection and timing of a set of zones to include in a service region. However, prior work required explicit enumeration of all possible sequences of investments. To address the combinatorial complexity of such enumeration, we propose a new variant "deep" RO policy using an efficient recurrent neural network (RNN) based ML method (CR-RNN policy) to sample sequences to forego the need for enumeration, making network design & timing policy tractable for large scale implementation. Experiments on multiple service region scenarios in New York City (NYC) shows the proposed policy substantially reduces the overall computational cost (time reduction for RO evaluation of > 90% of total investment sequences is achieved), with zero to near-zero gap compared to the benchmark. A case study of sequential service region design for expansion of MoD services in Brooklyn, NYC show that using the CR-RNN policy to determine optimal RO investment strategy yields a similar performance (0.5% within CR policy value) with significantly reduced computation time (about 5.4 times faster).