1,720,963 research outputs found
Efficient spectral domain technique for the frequency locking analysis of nonlinear oscillators
Full text linkAfter discussing an implementation of the harmonic balance technique that enables the efficient determination of the limit cycles for a nonlinear autonomous dynamical system, we consider the frequency locking of a set of oscillators that is studied by means of a proper extension of the aforementioned approach. Harmonic balance is also used for the numerical computation of the Floquet exponents and eigenvectors of the frequency locked limit cycle, thus enabling the assessment of its stability properties. The proposed technique is applied to the study of the frequency locking properties of a set of coupled Chua’s oscillators as a function of several parameters
Un metodo rigoroso per l'analisi dell'instabilità elettrotermica in dispositivi di potenza per applicazioni adalta frequenza
No full textA frequency-domain approach to the analysis of stability and bifurcations in nonlinear systems described by differential-algebraic equations
Full text linkA general numerical technique is proposed for the assessment of the stability of periodic solutions and the determination of bifurcations for limit cycles in autonomous nonlinear systems represented by ordinary differential equations in the differential-algebraic form. The method is based on the harmonic balance technique, and exploits the same Jacobian matrix of the nonlinear system used in the Newton iterative numerical solution of the harmonic balance equations for the determination of the periodic steady-state. To demonstrate the approach, it is applied to the determination of the bifurcation curves in the parameters' space of Chua's circuit with cubic nonlinearity, and to study the dynamics of the limit cycle of a Colpitts oscillato
Vibration energy harvesting enhancement in systems with modulated noise
No full textEnergy harvesting promises to make self-powered electronic systems feasible, and to increase the lifetime of battery powered systems almost indefinitely. It is based on the idea to scavenge power from the surrounding environment, in the form of electromagnetic radiation, solar light, temperature gradients, or mechanical vibrations, and to convert it into usable electrical energy. One bottleneck in this technology is the limited energy density of ambient noise, which requires high efficient energy harvesting systems. We show that, for systems with modulated noise, the collected energy can be maximized by a proper control of the state of the system, and we develop a procedure to design the optimal state
Kuramoto-like model of noisy oscillators
No full textAbstract: The Kuramoto model is a paradigm to describe the dynamics of nonlinear oscillators under the influence of external perturbations or couplings. It is based on the idea to reduce the state equations to a scalar differential equation, that defines the time evolution for the phase of the oscillator. In this paper we discuss the reduction procedure for nonlinear oscillators subject to stochastic perturbations. The result is that phase noise is a drift-diffusion process. It is shown that the unavoidable amplitude fluctuations do change the expected frequency, and the frequency shift depends on the amplitude variance. The theoretical results are illustrated with the help of an example
A critical discussion of the current collapse in multifinger HBTs based on Floquet stability analysis
No full textProjective embedding of dynamical systems: Uniform mean field equations
Full text linkWe study embeddings of continuous dynamical systems in larger dimensions via projector operators. We call this technique PEDS, projective embedding of dynamical systems, as the stable fixed point of the original system dynamics are recovered via projection from the higher dimensional space. In this paper we provide a general definition and prove that for a particular type of rank-1 projector operator, the uniform mean field projector, the equations of motion become a mean field approximation of the dynamical system. While in general the embedding depends on a specified variable ordering, the same is not true for the uniform mean field projector. We prove a variety of results on the relationship between the spectrum of the Jacobian for fixed points in the original and in the embedded system. Direct applications of PEDS can be non-convex optimization and machine learning
Memcomputing NP-complete problems in polynomial time using polynomial resources and collective states
Full text linkMemcomputing is a novel non-Turing paradigm of computation that uses interacting memory cells (memprocessors for short) to store and process information on the same physical platform. It was recently proven mathematically that memcomputing machines have the same computational power of nondeterministic Turing machines. Therefore, they can solve NP-complete problems in polynomial time and, using the appropriate architecture, with resources that only grow polynomially with the input size. The reason for this computational power stems from properties inspired by the brain and shared by any universal memcomputing machine, in particular intrinsic parallelism and information overhead, namely, the capability of compressing information in the collective state of the memprocessor network. We show an experimental demonstration of an actual memcomputing architecture that solves the NP-complete version of the subset sum problem in only one step and is composed of a number of memprocessors that scales linearly with the size of the problem. We have fabricated this architecture using standard microelectronic technology so that it can be easily realized in any laboratory setting. Although the particular machine presented here is eventually limited by noise—and will thus require error-correcting codes to scale to an arbitrary number of memprocessors—it represents the first proof of concept of a machine capable of working with the collective state of interacting memory cells, unlike the present-day single-state machines built using the von Neumann architectur
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