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Reminding Forgetful Organic Neuromorphic Device Networks

Felder, Daniel ; Muche, Katerina ; Linkhorst, John ; Wessling, Matthias (2022)
Reminding Forgetful Organic Neuromorphic Device Networks.
In: Neuromorphic Computing and Engineering, 2 (4)
doi: 10.1088/2634-4386/ac9c8a
Artikel, Bibliographie

Kurzbeschreibung (Abstract)

Organic neuromorphic device networks can accelerate neural network algorithms and directly integrate with microfluidic systems or living tissues. Proposed devices based on the bio-compatible conductive polymer PEDOT:PSS have shown high switching speeds and low energy demand. However, as electrochemical systems, they are prone to self-discharge through parasitic electrochemical reactions. Therefore, the network's synapses forget their trained conductance states over time. This work integrates single-device high-resolution charge transport models to simulate entire neuromorphic device networks and analyze the impact of self-discharge on network performance. Simulation of a single-layer nine-pixel image classification network commonly used in experimental demonstrations reveals no significant impact of self-discharge on training efficiency. And, even though the network's weights drift significantly during self-discharge, its predictions remain 100% accurate for over ten hours. On the other hand, a multi-layer network for the approximation of the circle function is shown to degrade significantly over twenty minutes with a final mean-squared-error loss of 0.4. We propose to counter the effect by periodically reminding the network based on a map between a synapse's current state, the time since the last reminder, and the weight drift. We show that this method with a map obtained through validated simulations can reduce the effective loss to below 0.1 even with worst-case assumptions. Finally, while the training of this network is affected by self-discharge, a good classification is still obtained. Electrochemical organic neuromorphic devices have not been integrated into larger device networks. This work predicts their behavior under nonideal conditions, mitigates the worst-case effects of parasitic self-discharge, and opens the path toward implementing fast and efficient neural networks on organic neuromorphic hardware.

Typ des Eintrags: Artikel
Erschienen: 2022
Autor(en): Felder, Daniel ; Muche, Katerina ; Linkhorst, John ; Wessling, Matthias
Art des Eintrags: Bibliographie
Titel: Reminding Forgetful Organic Neuromorphic Device Networks
Sprache: Englisch
Publikationsjahr: 2022
Verlag: IOP Publishing
Titel der Zeitschrift, Zeitung oder Schriftenreihe: Neuromorphic Computing and Engineering
Jahrgang/Volume einer Zeitschrift: 2
(Heft-)Nummer: 4
DOI: 10.1088/2634-4386/ac9c8a
Kurzbeschreibung (Abstract):

Organic neuromorphic device networks can accelerate neural network algorithms and directly integrate with microfluidic systems or living tissues. Proposed devices based on the bio-compatible conductive polymer PEDOT:PSS have shown high switching speeds and low energy demand. However, as electrochemical systems, they are prone to self-discharge through parasitic electrochemical reactions. Therefore, the network's synapses forget their trained conductance states over time. This work integrates single-device high-resolution charge transport models to simulate entire neuromorphic device networks and analyze the impact of self-discharge on network performance. Simulation of a single-layer nine-pixel image classification network commonly used in experimental demonstrations reveals no significant impact of self-discharge on training efficiency. And, even though the network's weights drift significantly during self-discharge, its predictions remain 100% accurate for over ten hours. On the other hand, a multi-layer network for the approximation of the circle function is shown to degrade significantly over twenty minutes with a final mean-squared-error loss of 0.4. We propose to counter the effect by periodically reminding the network based on a map between a synapse's current state, the time since the last reminder, and the weight drift. We show that this method with a map obtained through validated simulations can reduce the effective loss to below 0.1 even with worst-case assumptions. Finally, while the training of this network is affected by self-discharge, a good classification is still obtained. Electrochemical organic neuromorphic devices have not been integrated into larger device networks. This work predicts their behavior under nonideal conditions, mitigates the worst-case effects of parasitic self-discharge, and opens the path toward implementing fast and efficient neural networks on organic neuromorphic hardware.

Fachbereich(e)/-gebiet(e): 16 Fachbereich Maschinenbau
16 Fachbereich Maschinenbau > Fachgebiet Verfahrenstechnik elektrochemischer Systeme (VES)
Hinterlegungsdatum: 13 Sep 2023 11:13
Letzte Änderung: 13 Sep 2023 11:13
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