小柯机器人

科学家开发出分子忆阻器中的决策树
2021-09-05 12:30

美国德克萨斯农工大学R. Stanley Williams等研究人员合作开发出分子忆阻器中的决策树。该项研究成果发表在2021年9月1日出版的《自然》杂志上。

研究人员表示,新皮层中的神经元之间有大量的树突触互连,并嵌入了复杂的逻辑结构,这使复杂的决策大大超过了任何人工电子类似物。其物理复杂性远远超出了现有的电路制造技术:此外,大脑中的网络是动态可重构的,这为变化的环境提供了灵活性和适应性。相比之下,最先进的半导体逻辑电路是基于阈值开关的,这些阈值开关是硬连接的,用于执行预定的逻辑功能。

为了推进逻辑电路的性能,研究人员重新设想了基本的电子电路元件,并用纳米级的材料特性来表达了复杂的逻辑。研究人员利用电压驱动的条件逻辑在一个金属有机复合物的五个不同的分子氧化还原状态之间的互连性,并在一个单一的记忆体中嵌入有71个节点决策树的"丛林"(由多个if-then-else条件语句组成)。

这个分子记忆体(一个 "记忆电阻",一个全局无源电阻开关电路元件)的结果电流-电压特性表现出在一个扫描周期内两个电导水平之间有八个经常性和历史依赖的非易失性开关转换。每个分子氧化还原状态的身份是用原位拉曼光谱法确定的,并通过量子化学计算确认,这揭示了电子传输机制。通过使用只有这些元素的简单电路,研究人员在实验中展示了动态可重构的、交换和非交换状态逻辑的多变量决策树,这些决策树可在单一时间步骤中执行,例如,可以作为边缘计算的局部智能应用。

附:英文原文

Title: Decision trees within a molecular memristor

Author: Goswami, Sreetosh, Pramanick, Rajib, Patra, Abhijeet, Rath, Santi Prasad, Foltin, Martin, Ariando, A., Thompson, Damien, Venkatesan, T., Goswami, Sreebrata, Williams, R. Stanley

Issue&Volume: 2021-09-01

Abstract: Profuse dendritic-synaptic interconnections among neurons in the neocortex embed intricate logic structures enabling sophisticated decision-making that vastly outperforms any artificial electronic analogues1,2,3. The physical complexity is far beyond existing circuit fabrication technologies: moreover, the network in a brain is dynamically reconfigurable, which provides flexibility and adaptability to changing environments4,5,6. In contrast, state-of-the-art semiconductor logic circuits are based on threshold switches that are hard-wired to perform predefined logic functions. To advance the performance of logic circuits, we are re-imagining fundamental electronic circuit elements by expressing complex logic in nanometre-scale material properties. Here we use voltage-driven conditional logic interconnectivity among five distinct molecular redox states of a metal–organic complex to embed a ‘thicket’ of decision trees (composed of multiple if-then-else conditional statements) having 71 nodes within a single memristor. The resultant current–voltage characteristic of this molecular memristor (a 'memory resistor', a globally passive resistive-switch circuit element that axiomatically complements the set of capacitor, inductor and resistor) exhibits eight recurrent and history-dependent non-volatile switching transitions between two conductance levels in a single sweep cycle. The identity of each molecular redox state was determined with in situ Raman spectroscopy and confirmed by quantum chemical calculations, revealing the electron transport mechanism. Using simple circuits of only these elements, we experimentally demonstrate dynamically reconfigurable, commutative and non-commutative stateful logic in multivariable decision trees that execute in a single time step and can, for example, be applied as local intelligence in edge computing7,8,9.

DOI: 10.1038/s41586-021-03748-0

Source: https://www.nature.com/articles/s41586-021-03748-0

Nature:《自然》,创刊于1869年。隶属于施普林格·自然出版集团,最新IF:69.504
官方网址:http://www.nature.com/
投稿链接:http://www.nature.com/authors/submit_manuscript.html


本期文章:《自然》:Online/在线发表

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