生物智能的主要特征之一是能源效率,持续适应能力以及通过不确定性量化的风险管理。到目前为止,神经形态工程主要是由实施节能机器从生物学大脑的基于时间的计算范式中获得灵感的目标的驱动。在本文中,我们采取了朝着设计神经形态系统设计的步骤,这些系统能够适应改变学习任务,同时产生良好的不确定性量化估计。为此,我们得出了在贝叶斯持续学习框架内尖峰神经网络(SNN)的在线学习规则。在其中,每个突触重量都由参数表示,这些参数量化了先验知识和观察到的数据引起的当前认知不确定性。提出的在线规则在观察到数据时以流方式更新分布参数。我们实例化了实用值和二元突触权重的建议方法。使用英特尔熔岩平台的实验结果表明,贝叶斯在适应能力和不确定性定量方面的经常学习优点。
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神经形态数据携带由尖峰编码的时空模式的信息。因此,神经形态计算中的核心问题是训练尖峰神经网络(SNNS)以再现时加速时空尖峰图案响应于给定的尖刺刺激。通过将每个输入分配给特定期望的输出尖刺序列,大多数现有方法通过分配每个输入来模拟SNN的输入输出行为。相比之下,为了充分利用尖峰的时间编码能力,这项工作建议训练SNN,以匹配尖刺信号的分布而不是单独的尖峰信号。为此,本文介绍了一种新颖的混合架构,包括通过SNN实现的条件发生器,以及由传统人工神经网络(ANN)实现的鉴别器。 ANN的作用是在遵循生成的对抗网络(GANS)原则的对抗迭代学习策略中对SNN的培训期间提供反馈。为了更好地捕获多模态的时空分布,所提出的方法被称为Spikegan - 进一步扩展到支持发电机重量的贝叶斯学习。最后,通过提出Spikegan的在线元学习变量来解决具有时变统计数据的设置。实验与基于(静态)信念网络的现有解决方案相比,对所提出的方法的优点带来了洞察的洞察力,以及最大可能性(或经验风险最小化)。
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Two of the main principles underlying the life cycle of an artificial intelligence (AI) module in communication networks are adaptation and monitoring. Adaptation refers to the need to adjust the operation of an AI module depending on the current conditions; while monitoring requires measures of the reliability of an AI module's decisions. Classical frequentist learning methods for the design of AI modules fall short on both counts of adaptation and monitoring, catering to one-off training and providing overconfident decisions. This paper proposes a solution to address both challenges by integrating meta-learning with Bayesian learning. As a specific use case, the problems of demodulation and equalization over a fading channel based on the availability of few pilots are studied. Meta-learning processes pilot information from multiple frames in order to extract useful shared properties of effective demodulators across frames. The resulting trained demodulators are demonstrated, via experiments, to offer better calibrated soft decisions, at the computational cost of running an ensemble of networks at run time. The capacity to quantify uncertainty in the model parameter space is further leveraged by extending Bayesian meta-learning to an active setting. In it, the designer can select in a sequential fashion channel conditions under which to generate data for meta-learning from a channel simulator. Bayesian active meta-learning is seen in experiments to significantly reduce the number of frames required to obtain efficient adaptation procedure for new frames.
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这项工作仔细研究了传统的机器学习方法通​​过可靠性和鲁棒性的镜头应用于无线通信问题。深度学习技术采用了常见的框架,并已知提供校准较差的决策,这些决策不会再现由训练数据规模的限制引起的真正不确定性。贝叶斯学习原则上能够解决这一缺点,但实际上,模型错误指定和异常值的存在损害。在无线通信设置中,这两个问题都普遍存在,其中机器学习模型的能力受资源限制的影响,培训数据受噪声和干扰的影响。在这种情况下,我们探讨了强大的贝叶斯学习框架的应用。经过教程式的贝叶斯学习介绍,我们就精确,校准和对异常值和错误指定的鲁棒性进行了强大的贝叶斯学习对几个重要的无线沟通问题的优点。
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为了在专门的神经形态硬件中进行节能计算,我们提出了尖峰神经编码,这是基于预测性编码理论的人工神经模型家族的实例化。该模型是同类模型,它是通过在“猜测和检查”的永无止境过程中运行的,神经元可以预测彼此的活动值,然后调整自己的活动以做出更好的未来预测。我们系统的互动性,迭代性质非常适合感官流预测的连续时间表述,并且如我们所示,模型的结构产生了局部突触更新规则,可以用来补充或作为在线峰值定位的替代方案依赖的可塑性。在本文中,我们对模型的实例化进行了实例化,该模型包括泄漏的集成和火灾单元。但是,我们系统所在的框架自然可以结合更复杂的神经元,例如Hodgkin-Huxley模型。我们在模式识别方面的实验结果证明了当二进制尖峰列车是通信间通信的主要范式时,模型的潜力。值得注意的是,尖峰神经编码在分类绩效方面具有竞争力,并且在从任务序列中学习时会降低遗忘,从而提供了更经济的,具有生物学上的替代品,可用于流行的人工神经网络。
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We propose that in order to harness our understanding of neuroscience toward machine learning, we must first have powerful tools for training brain-like models of learning. Although substantial progress has been made toward understanding the dynamics of learning in the brain, neuroscience-derived models of learning have yet to demonstrate the same performance capabilities as methods in deep learning such as gradient descent. Inspired by the successes of machine learning using gradient descent, we demonstrate that models of neuromodulated synaptic plasticity from neuroscience can be trained in Spiking Neural Networks (SNNs) with a framework of learning to learn through gradient descent to address challenging online learning problems. This framework opens a new path toward developing neuroscience inspired online learning algorithms.
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神经形态计算是一种新兴的计算范式,它从批处理的处理转向在线,事件驱动的流数据处理。当神经形态芯片与基于尖峰的传感器结合在一起时,只有在峰值时间内记录相关事件并证明对变化条件的低延迟响应时,才能通过消耗能量来固有地适应数据分布的“语义”。环境。本文为神经形态无线网络系统系统提出了端到端设计,该系统集成了基于尖峰的传感,处理和通信。在拟议的神经系统系统中,每个传感设备都配备了神经形态传感器,尖峰神经网络(SNN)和带有多个天线的脉冲无线电发射器。传输发生在配备了多Antenna脉冲无线电接收器和SNN的接收器上的共享褪色通道上进行。为了使接收器适应褪色的通道条件,我们引入了一项超网络,以使用飞行员控制解码SNN的权重。飞行员,编码SNN,解码SNN和超网络经过多个通道实现的共同训练。该系统被证明可以显着改善基于传统的基于框架的数字解决方案以及替代性非自适应训练方法,从时间到准确性和能源消耗指标方面。
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现代深度学习方法构成了令人难以置信的强大工具,以解决无数的挑战问题。然而,由于深度学习方法作为黑匣子运作,因此与其预测相关的不确定性往往是挑战量化。贝叶斯统计数据提供了一种形式主义来理解和量化与深度神经网络预测相关的不确定性。本教程概述了相关文献和完整的工具集,用于设计,实施,列车,使用和评估贝叶斯神经网络,即使用贝叶斯方法培训的随机人工神经网络。
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在基于人工神经网络的终身学习系统中,最大的障碍之一是在遇到新信息时无法保留旧知识。这种现象被称为灾难性遗忘。在本文中,我们提出了一种新型的连接主义架构,即顺序的神经编码网络,在从数据点流中学习时忘记了,并且与当今的网络不同,它不会通过流行的错误反向传播来学习。基于预测性处理的神经认知理论,我们的模型以生物学上可行的方式适应了突触,而另一个神经系统学会了指导和控制这种类似皮层的结构,模仿了一些基础神经节的某些任务连续控制功能。在我们的实验中,我们证明了与标准神经模型相比,我们的自组织系统经历的遗忘大大降低,表现优于先前提出的方法,包括基于排练/数据缓冲的方法,包括标准(SplitMnist,SplitMnist,Split Mnist等) 。)和定制基准测试,即使以溪流式的方式进行了训练。我们的工作提供了证据表明,在实际神经元系统中模仿机制,例如本地学习,横向竞争,可以产生新的方向和可能性,以应对终身机器学习的巨大挑战。
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已知生物制剂在他们的生活过程中学习许多不同的任务,并且能够重新审视以前的任务和行为,而没有表现不损失。相比之下,人工代理容易出于“灾难性遗忘”,在以前任务上的性能随着所获取的新的任务而恶化。最近使用该方法通过鼓励参数保持接近以前任务的方法来解决此缺点。这可以通过(i)使用特定的参数正常数来完成,该参数正常数是在参数空间中映射合适的目的地,或(ii)通过将渐变投影到不会干扰先前任务的子空间来指导优化旅程。然而,这些方法通常在前馈和经常性神经网络中表现出子分子表现,并且经常性网络对支持生物持续学习的神经动力学研究感兴趣。在这项工作中,我们提出了自然的持续学习(NCL),一种统一重量正则化和预测梯度下降的新方法。 NCL使用贝叶斯重量正常化来鼓励在收敛的所有任务上进行良好的性能,并将其与梯度投影结合使用先前的精度,这可以防止在优化期间陷入灾难性遗忘。当应用于前馈和经常性网络中的连续学习问题时,我们的方法占据了标准重量正则化技术和投影的方法。最后,训练有素的网络演变了特定于任务特定的动态,这些动态被认为是学习的新任务,类似于生物电路中的实验结果。
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When used in complex engineered systems, such as communication networks, artificial intelligence (AI) models should be not only as accurate as possible, but also well calibrated. A well-calibrated AI model is one that can reliably quantify the uncertainty of its decisions, assigning high confidence levels to decisions that are likely to be correct and low confidence levels to decisions that are likely to be erroneous. This paper investigates the application of conformal prediction as a general framework to obtain AI models that produce decisions with formal calibration guarantees. Conformal prediction transforms probabilistic predictors into set predictors that are guaranteed to contain the correct answer with a probability chosen by the designer. Such formal calibration guarantees hold irrespective of the true, unknown, distribution underlying the generation of the variables of interest, and can be defined in terms of ensemble or time-averaged probabilities. In this paper, conformal prediction is applied for the first time to the design of AI for communication systems in conjunction to both frequentist and Bayesian learning, focusing on demodulation, modulation classification, and channel prediction.
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The term ``neuromorphic'' refers to systems that are closely resembling the architecture and/or the dynamics of biological neural networks. Typical examples are novel computer chips designed to mimic the architecture of a biological brain, or sensors that get inspiration from, e.g., the visual or olfactory systems in insects and mammals to acquire information about the environment. This approach is not without ambition as it promises to enable engineered devices able to reproduce the level of performance observed in biological organisms -- the main immediate advantage being the efficient use of scarce resources, which translates into low power requirements. The emphasis on low power and energy efficiency of neuromorphic devices is a perfect match for space applications. Spacecraft -- especially miniaturized ones -- have strict energy constraints as they need to operate in an environment which is scarce with resources and extremely hostile. In this work we present an overview of early attempts made to study a neuromorphic approach in a space context at the European Space Agency's (ESA) Advanced Concepts Team (ACT).
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Spiking neural networks (SNN) are a viable alternative to conventional artificial neural networks when energy efficiency and computational complexity are of importance. A major advantage of SNNs is their binary information transfer through spike trains. The training of SNN has, however, been a challenge, since neuron models are non-differentiable and traditional gradient-based backpropagation algorithms cannot be applied directly. Furthermore, spike-timing-dependent plasticity (STDP), albeit being a spike-based learning rule, updates weights locally and does not optimize for the output error of the network. We present desire backpropagation, a method to derive the desired spike activity of neurons from the output error. The loss function can then be evaluated locally for every neuron. Incorporating the desire values into the STDP weight update leads to global error minimization and increasing classification accuracy. At the same time, the neuron dynamics and computational efficiency of STDP are maintained, making it a spike-based supervised learning rule. We trained three-layer networks to classify MNIST and Fashion-MNIST images and reached an accuracy of 98.41% and 87.56%, respectively. Furthermore, we show that desire backpropagation is computationally less complex than backpropagation in traditional neural networks.
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在当前的嘈杂中间尺度量子(NISQ)时代,量子机学习正在成为基于程序门的量子计算机的主要范式。在量子机学习中,对量子电路的门进行了参数化,并且参数是根据数据和电路输出的测量来通过经典优化来调整的。参数化的量子电路(PQC)可以有效地解决组合优化问题,实施概率生成模型并进行推理(分类和回归)。该专着为具有概率和线性代数背景的工程师的观众提供了量子机学习的独立介绍。它首先描述了描述量子操作和测量所必需的必要背景,概念和工具。然后,它涵盖了参数化的量子电路,变异量子本质层以及无监督和监督的量子机学习公式。
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An obstacle to artificial general intelligence is set by the continual learning of multiple tasks of different nature. Recently, various heuristic tricks, both from machine learning and from neuroscience angles, were proposed, but they lack a unified theory ground. Here, we focus on the continual learning in single-layered and multi-layered neural networks of binary weights. A variational Bayesian learning setting is thus proposed, where the neural network is trained in a field-space, rather than the gradient-ill-defined discrete-weight space, and furthermore, the weight uncertainty is naturally incorporated, and modulates the synaptic resources among tasks. From a physics perspective, we translate the variational continual learning into the Franz-Parisi thermodynamic potential framework, where the previous task knowledge acts as a prior and a reference as well. Therefore, the learning performance can be analytically studied with mean-field order parameters, whose predictions coincide with the numerical experiments using stochastic gradient descent methods. Our proposed principled frameworks also connect to elastic weight consolidation, and neuroscience inspired metaplasticity, providing a theory-grounded method for the real-world multi-task learning with deep networks.
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尖峰神经网络(SNN)是大脑中低功率,耐断层的信息处理的基础,并且在适当的神经形态硬件加速器上实施时,可能构成传统深层神经网络的能力替代品。但是,实例化解决复杂的计算任务的SNN在Silico中仍然是一个重大挑战。替代梯度(SG)技术已成为培训SNN端到端的标准解决方案。尽管如此,它们的成功取决于突触重量初始化,类似于常规的人工神经网络(ANN)。然而,与ANN不同,它仍然难以捉摸地构成SNN的良好初始状态。在这里,我们为受到大脑中通常观察到的波动驱动的策略启发的SNN制定了一般初始化策略。具体而言,我们为数据依赖性权重初始化提供了实用的解决方案,以确保广泛使用的泄漏的集成和传火(LIF)神经元的波动驱动。我们从经验上表明,经过SGS培训时,SNN遵循我们的策略表现出卓越的学习表现。这些发现概括了几个数据集和SNN体系结构,包括完全连接,深度卷积,经常性和更具生物学上合理的SNN遵守Dale的定律。因此,波动驱动的初始化提供了一种实用,多功能且易于实现的策略,可改善神经形态工程和计算神经科学的不同任务的SNN培训绩效。
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这是一门专门针对STEM学生开发的介绍性机器学习课程。我们的目标是为有兴趣的读者提供基础知识,以在自己的项目中使用机器学习,并将自己熟悉术语作为进一步阅读相关文献的基础。在这些讲义中,我们讨论受监督,无监督和强化学习。注释从没有神经网络的机器学习方法的说明开始,例如原理分析,T-SNE,聚类以及线性回归和线性分类器。我们继续介绍基本和先进的神经网络结构,例如密集的进料和常规神经网络,经常性的神经网络,受限的玻尔兹曼机器,(变性)自动编码器,生成的对抗性网络。讨论了潜在空间表示的解释性问题,并使用梦和对抗性攻击的例子。最后一部分致力于加强学习,我们在其中介绍了价值功能和政策学习的基本概念。
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本文介绍了分类器校准原理和实践的简介和详细概述。校准的分类器正确地量化了与其实例明智的预测相关的不确定性或信心水平。这对于关键应用,最佳决策,成本敏感的分类以及某些类型的上下文变化至关重要。校准研究具有丰富的历史,其中几十年来预测机器学习作为学术领域的诞生。然而,校准兴趣的最近增加导致了新的方法和从二进制到多种子体设置的扩展。需要考虑的选项和问题的空间很大,并导航它需要正确的概念和工具集。我们提供了主要概念和方法的介绍性材料和最新的技术细节,包括适当的评分规则和其他评估指标,可视化方法,全面陈述二进制和多字数分类的HOC校准方法,以及几个先进的话题。
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We propose a novel backpropagation algorithm for training spiking neural networks (SNNs) that encodes information in the relative multiple spike timing of individual neurons without single-spike restrictions. The proposed algorithm inherits the advantages of conventional timing-based methods in that it computes accurate gradients with respect to spike timing, which promotes ideal temporal coding. Unlike conventional methods where each neuron fires at most once, the proposed algorithm allows each neuron to fire multiple times. This extension naturally improves the computational capacity of SNNs. Our SNN model outperformed comparable SNN models and achieved as high accuracy as non-convolutional artificial neural networks. The spike count property of our networks was altered depending on the time constant of the postsynaptic current and the membrane potential. Moreover, we found that there existed the optimal time constant with the maximum test accuracy. That was not seen in conventional SNNs with single-spike restrictions on time-to-fast-spike (TTFS) coding. This result demonstrates the computational properties of SNNs that biologically encode information into the multi-spike timing of individual neurons. Our code would be publicly available.
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我们训练神经形态硬件芯片以通过变分能最小化近似Quantum旋转模型的地面状态。与使用马尔可夫链蒙特卡罗进行样品生成的变分人工神经网络相比,这种方法具有优点:神经形态器件以快速和固有的并行方式产生样品。我们开发培训算法,并将其应用于横向场介绍模型,在中等系统尺寸下显示出良好的性能($ n \ LEQ 10 $)。系统的普遍开心研究表明,较大系统尺寸的可扩展性主要取决于样品质量,该样品质量受到模拟神经芯片上的参数漂移的限制。学习性能显示阈值行为作为ansatz的变分参数的数量的函数,大约为50美元的隐藏神经元,足以表示关键地位,最高$ n = 10 $。网络参数的6 + 1位分辨率不会限制当前设置中的可达近似质量。我们的工作为利用神经形态硬件的能力提供了一种重要的一步,以解决量子数量问题中的维数诅咒。
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