Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Self-oscillation   Physicists are very familiar with forced and parametric resonance, but
usually not with self-oscillation, a property of certain dynamical systems that
gives rise to a great variety of vibrations, both useful and destructive. In a
self-oscillator, the driving force is controlled by the oscillation itself so
that it acts in phase with the velocity, causing a negative damping that feeds
energy into the vibration: no external rate needs to be adjusted to the
resonant frequency. The famous collapse of the Tacoma Narrows bridge in 1940,
often attributed by introductory physics texts to forced resonance, was
actually a self-oscillation, as was the swaying of the London Millennium
Footbridge in 2000. Clocks are self-oscillators, as are bowed and wind musical
instruments. The heart is a "relaxation oscillator," i.e., a non-sinusoidal
self-oscillator whose period is determined by sudden, nonlinear switching at
thresholds. We review the general criterion that determines whether a linear
system can self-oscillate. We then describe the limiting cycles of the simplest
nonlinear self-oscillators, as well as the ability of two or more coupled
self-oscillators to become spontaneously synchronized ("entrained"). We
characterize the operation of motors as self-oscillation and prove a theorem
about their limit efficiency, of which Carnot's theorem for heat engines
appears as a special case. We briefly discuss how self-oscillation applies to
servomechanisms, Cepheid variable stars, lasers, and the macroeconomic business
cycle, among other applications. Our emphasis throughout is on the energetics
of self-oscillation, often neglected by the literature on nonlinear dynamical
systems.

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The categories of this paper are: plasm-ph
19
The categories of this paper are: eess
26
The categories of this paper are: bayes-an
12
The categories of this paper are: nucl-th
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The categories of this paper are: atom-ph
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The categories of this paper are: solv-int
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The categories of this paper are: chem-ph
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The categories of this paper are: q-alg
4
The categories of this paper are: cond-mat
10
The categories of this paper are: q-bio
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The categories of this paper are: supr-con
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The categories of this paper are: alg-geom
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The categories of this paper are: astro-ph
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The categories of this paper are: q-fin
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The categories of this paper are: patt-sol
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The categories of this paper are: funct-an