150 research outputs found
Hierarchical Composition of Memristive Networks for Real-Time Computing
Advances in materials science have led to physical instantiations of
self-assembled networks of memristive devices and demonstrations of their
computational capability through reservoir computing. Reservoir computing is an
approach that takes advantage of collective system dynamics for real-time
computing. A dynamical system, called a reservoir, is excited with a
time-varying signal and observations of its states are used to reconstruct a
desired output signal. However, such a monolithic assembly limits the
computational power due to signal interdependency and the resulting correlated
readouts. Here, we introduce an approach that hierarchically composes a set of
interconnected memristive networks into a larger reservoir. We use signal
amplification and restoration to reduce reservoir state correlation, which
improves the feature extraction from the input signals. Using the same number
of output signals, such a hierarchical composition of heterogeneous small
networks outperforms monolithic memristive networks by at least 20% on waveform
generation tasks. On the NARMA-10 task, we reduce the error by up to a factor
of 2 compared to homogeneous reservoirs with sigmoidal neurons, whereas single
memristive networks are unable to produce the correct result. Hierarchical
composition is key for solving more complex tasks with such novel nano-scale
hardware
Simple Floating Voltage-Controlled Memductor Emulator for Analog Applications
The topic of memristive circuits is a novel topic in circuit theory that has become of great importance due to its unique behavior which is useful in different applications. But since there is a lack of memristor samples, a memristor emulator is used instead of a solid state memristor. In this paper, a new simple floating voltage-controlled memductor emulator is introduced which is implemented using commercial off the shelf (COTS) realization. The mathematical modeling of the proposed circuit is derived to match the theoretical model. The proposed circuit is tested experimentally using different excitation signals such as sinusoidal, square, and triangular waves showing an excellent matching with previously reported simulations
Forced synchronization of an oscillator with a line of equilibria
The model of a non-autonomous memristor-based oscillator with a line of
equilibria is studied. A numerical simulation of the system driven by a
periodical force is combined with a theoretical analysis by means of the
quasi-harmonic reduction. Both two mechanisms of synchronization are
demonstrated: capture of the phase and frequency of oscillations and
suppression by an external signal. Classification of undamped oscillations in
an autonomous system with a line of equilibria as a special kind of
self-sustained oscillations is concluded due to the possibility to observe the
effect of frequency-phase locking in the same system in the presence of an
external influence. It is established that the occurrence of phase locking in
the considered system continuously depends both on parameter values and initial
conditions. The simultaneous dependence of synchronization area boundaries on
the initial conditions and the parameter values is also shown.Comment: 10 pages, 9 figure
- …