Efficient and robust control using spiking neural networks (SNNs) is still an open problem. Whilst behaviour of biological agents is produced through sparse and irregular spiking patterns, which provide both robust and efficient control, the activity patterns in most artificial spiking neural networks used for control are dense and regular -- resulting in potentially less efficient codes. Additionally, for most existing control solutions network training or optimization is necessary, even for fully identified systems, complicating their implementation in on-chip low-power solutions. The neuroscience theory of Spike Coding Networks (SCNs) offers a fully analytical solution for implementing dynamical systems in recurrent spiking neural networks -- while maintaining irregular, sparse, and robust spiking activity -- but it's not clear how to directly apply it to control problems. Here, we extend SCN theory by incorporating closed-form optimal estimation and control. The resulting networks work as a spiking equivalent of a linear-quadratic-Gaussian controller. We demonstrate robust spiking control of simulated spring-mass-damper and cart-pole systems, in the face of several perturbations, including input- and system-noise, system disturbances, and neural silencing. As our approach does not need learning or optimization, it offers opportunities for deploying fast and efficient task-specific on-chip spiking controllers with biologically realistic activity.
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值得怀疑的是,动物具有其四肢的完美逆模型(例如,必须在每个关节上应用什么肌肉收缩才能到达太空中的特定位置)。但是,在机器人控制中,将ARM的最终效应器移至目标位置或沿目标轨迹需要准确的前进和逆模型。在这里,我们证明,通过从交互中学习过渡(正向)模型,我们可以使用它来推动摊销策略的学习。因此,我们重新审视了与深度主动推理框架有关的策略优化,并描述了一个模块化神经网络体系结构,该模块化神经网络体系结构同时从预测错误中学习了系统动力学以及生成合适的连续控制命令以达到所需参考位置的随机策略。我们通过将模型与线性二次调节器的基线进行比较来评估该模型,并以其他步骤来朝着类似人类的运动控制方向进行比较。
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世界由对象组成:具有独立属性和动态的不同实体。为了使代理人聪明地与世界互动,他们必须将感觉输入转化为描述每个对象的边界特征。这些基于对象的表示形成了计划行为的自然基础。主动推断(AIF)是对感知和行动的影响力的统一说明,但是现有的AIF模型并未利用这种重要的归纳偏见。为了解决这个问题,我们介绍了“基于对象的主动推理”(OBAI),将AIF与最近基于对象的神经网络结合在一起。 Obai代表具有不同变异信念的不同对象,并使用选择性注意来将输入输入到相应的对象插槽中。对象表示具有独立的基于动作的动态。动力学和生成模型是从简单环境(主动的多-DSPRITES)的经验中学到的。我们表明,奥贝(Obai)学会了从视频输入中正确分割动作扰动的对象,并将这些对象操纵到任意目标。
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适应外部和内部变化是不确定环境中机器人系统的专业。在这里,我们提出了一种用于工业武器的新型多思科有源推理扭矩控制器,其显示如何使用预测来解决适应性。我们的控制器灵感来自预测性大脑假设,通过在简化架构的同时结合高速和高维传感器输入(例如,原始图像)的学习和多模式集成来提高当前有源推断方法的能力。我们通过将其与先前的有源推理基准和经典控制器进行比较,对我们的行为进行比较,对我们的行为进行了比较了定性和定量适应能力和控制精度,对我们的行为进行了系统评估。结果表明,由于多模式滤波,具有高噪声抑制的目标导向的控制精度提高,并且对动态惯性变化,弹性约束和人类干扰的适应性而无需释放模型,也不需要参数重新定量。
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有效推论是一种数学框架,它起源于计算神经科学,作为大脑如何实现动作,感知和学习的理论。最近,已被证明是在不确定性下存在国家估算和控制问题的有希望的方法,以及一般的机器人和人工代理人的目标驱动行为的基础。在这里,我们审查了最先进的理论和对国家估计,控制,规划和学习的积极推断的实现;描述当前的成就,特别关注机器人。我们展示了相关实验,以适应,泛化和稳健性而言说明其潜力。此外,我们将这种方法与其他框架联系起来,并讨论其预期的利益和挑战:使用变分贝叶斯推理具有功能生物合理性的统一框架。
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Algorithms that involve both forecasting and optimization are at the core of solutions to many difficult real-world problems, such as in supply chains (inventory optimization), traffic, and in the transition towards carbon-free energy generation in battery/load/production scheduling in sustainable energy systems. Typically, in these scenarios we want to solve an optimization problem that depends on unknown future values, which therefore need to be forecast. As both forecasting and optimization are difficult problems in their own right, relatively few research has been done in this area. This paper presents the findings of the ``IEEE-CIS Technical Challenge on Predict+Optimize for Renewable Energy Scheduling," held in 2021. We present a comparison and evaluation of the seven highest-ranked solutions in the competition, to provide researchers with a benchmark problem and to establish the state of the art for this benchmark, with the aim to foster and facilitate research in this area. The competition used data from the Monash Microgrid, as well as weather data and energy market data. It then focused on two main challenges: forecasting renewable energy production and demand, and obtaining an optimal schedule for the activities (lectures) and on-site batteries that lead to the lowest cost of energy. The most accurate forecasts were obtained by gradient-boosted tree and random forest models, and optimization was mostly performed using mixed integer linear and quadratic programming. The winning method predicted different scenarios and optimized over all scenarios jointly using a sample average approximation method.
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A reduced order model of a generic submarine is presented. Computational fluid dynamics (CFD) results are used to create and validate a model that includes depth dependence and the effect of waves on the craft. The model and the procedure to obtain its coefficients are discussed, and examples of the data used to obtain the model coefficients are presented. An example of operation following a complex path is presented and results from the reduced order model are compared to those from an equivalent CFD calculation. The controller implemented to complete these maneuvers is also presented.
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Neural machine translation (NMT) has become the de-facto standard in real-world machine translation applications. However, NMT models can unpredictably produce severely pathological translations, known as hallucinations, that seriously undermine user trust. It becomes thus crucial to implement effective preventive strategies to guarantee their proper functioning. In this paper, we address the problem of hallucination detection in NMT by following a simple intuition: as hallucinations are detached from the source content, they exhibit encoder-decoder attention patterns that are statistically different from those of good quality translations. We frame this problem with an optimal transport formulation and propose a fully unsupervised, plug-in detector that can be used with any attention-based NMT model. Experimental results show that our detector not only outperforms all previous model-based detectors, but is also competitive with detectors that employ large models trained on millions of samples.
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As more and more conversational and translation systems are deployed in production, it is essential to implement and to develop effective control mechanisms guaranteeing their proper functioning and security. An essential component to ensure safe system behavior is out-of-distribution (OOD) detection, which aims at detecting whether an input sample is statistically far from the training distribution. Although OOD detection is a widely covered topic in classification tasks, it has received much less attention in text generation. This paper addresses the problem of OOD detection for machine translation and dialog generation from an operational perspective. Our contributions include: (i) RAINPROOF a Relative informAItioN Projection ODD detection framework; and (ii) a more operational evaluation setting for OOD detection. Surprisingly, we find that OOD detection is not necessarily aligned with task-specific measures. The OOD detector may filter out samples that are well processed by the model and keep samples that are not, leading to weaker performance. Our results show that RAINPROOF breaks this curse and achieve good results in OOD detection while increasing performance.
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Variance parameter estimation in linear mixed models is a challenge for many classical nonlinear optimization algorithms due to the positive-definiteness constraint of the random effects covariance matrix. We take a completely novel view on parameter estimation in linear mixed models by exploiting the intrinsic geometry of the parameter space. We formulate the problem of residual maximum likelihood estimation as an optimization problem on a Riemannian manifold. Based on the introduced formulation, we give geometric higher-order information on the problem via the Riemannian gradient and the Riemannian Hessian. Based on that, we test our approach with Riemannian optimization algorithms numerically. Our approach yields a higher quality of the variance parameter estimates compared to existing approaches.
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