Control Strategies to Optimize Graph Coloring via M-CNNs with Locally-Active NbO_xMemristors

Resistive switching and role of interfaces in memristive devices based on amorphous NbOx grown by anodic oxidation

“…10 Memristive devices based on NbO x have been also largely studied for their threshold switching properties, useful as a selector in memory arrays. [11][12][13][14][15][16][17][18][19][20][21][22][23] In all these works, the niobium oxide switching medium is obtained using conventional deposition techniques such as RF sputtering both starting from a NbO x target and from a pure Nb target in an oxygen atmosphere to control its stoichiometry and also by using pulsed laser deposition (PLD), ALD and sol-gel methods. [24][25][26][27][28][29] Recently, anodic oxidation has been proposed as a promising alternative low-cost and easy-to-use technique in the realization of RS devices with high performances.…”

“…10 Memristive devices based on NbO x have been also largely studied for their threshold switching properties, useful as a selector in memory arrays. 11–23 In all these works, the niobium oxide switching medium is obtained using conventional deposition techniques such as RF sputtering both starting from a NbO x target and from a pure Nb target in an oxygen atmosphere to control its stoichiometry and also by using pulsed laser deposition (PLD), ALD and sol–gel methods. 24–29…”

Graph Coloring via Locally-Active Memristor Oscillatory Networks

“…Inspired from simulated annealing algorithms [46] as well from our latest approachreferred to as Kick-Fly-Catch paradigm-for humanoid robot motion control [47,48], the proposed strategy ( [31,33]) is based upon supplying energy to the system, while it sits in an impasse state. Particularly, a pulse is applied to an ad-hoc oscillator by offsetting the value V S of its DC voltage source by an appropriate amount ∆V S for a given time interval of length T p .…”

“…Section 4 presents a rigorous iterative procedure for coloring a graph via the network phase dynamics. Importantly, control paradigms to resolve local minima-based impasse conditions [33] are proposed in Section 5, which further compares the performance of the proposed spike-based computing engine, endowed with ad hoc circuitry to implement such strategies, with the solutions of state-of-the-art software and hardware competitor systems. Finally, conclusions are drawn in Section 6.…”

“…If, for two or more k-values, the application of the iterative graph coloring procedure to the vertex ranking, resulting from the phase shift ordering, obtained by adding up the relevant offset ∆ϕ k to the phase shift ϕ (s) i of oscillator i in the steady-state relative phase shift vector ϕ (s) , leads to the identification of the same lowest number of colors, the selection goes for the ∆ϕ k -candidate featuring the largest modulus. Finally, the pulse amplitude of the T p -long stimulus to be applied to oscillator i is obtained from Equation (33).…”