12,606 research outputs found
Small noise asymptotic of the timing jitter in soliton transmission
We consider the problem of the error in soliton transmission in long-haul
optical fibers caused by the spontaneous emission of noise inherent to
amplification. We study two types of noises driving the stochastic focusing
cubic one dimensional nonlinear Schr\"{o}dinger equation which appears in
physics in that context. We focus on the fluctuations of the mass and arrival
time or timing jitter. We give the small noise asymptotic of the tails of these
two quantities for the two types of noises. We are then able to prove several
results from physics among which the Gordon--Haus effect which states that the
fluctuation of the arrival time is a much more limiting factor than the
fluctuation of the mass. The physical results had been obtained with arguments
difficult to fully justify mathematically.Comment: Published in at http://dx.doi.org/10.1214/07-AAP449 the Annals of
Applied Probability (http://www.imstat.org/aap/) by the Institute of
Mathematical Statistics (http://www.imstat.org
Optical drive of macroscopic mechanical motion by a single two-level system
A quantum emitter coupled to a nano-mechanical oscillator is a hybrid system
where a macroscopic degree of freedom is coupled to a purely quantum system.
Recent progress in nanotechnology has led to the realization of such devices by
embedding single artificial atoms like quantum dots or superconducting qubits
into vibrating wires or membranes, opening up new perspectives for quantum
information technologies and for the exploration of the quantum-classical
boundary. In this letter, we show that the quantum emitter can be turned into a
strikingly efficient light-controlled source of mechanical power, by exploiting
constructive interferences of classical phonon fields in the mechanical
oscillator. We show that this mechanism can be used as a novel strategy to
carry out low-background non-destructive single-shot measurement of an
optically active quantum bit state.Comment: 8 pages, 5 figure
A virtual actuator approach for the secure control of networked LPV systems under pulse-width modulated DoS attacks
In this paper, we formulate and analyze the problem of secure control in the context of networked linear parameter varying (LPV) systems. We consider an energy-constrained, pulse-width modulated (PWM) jammer, which corrupts the control communication channel by performing a denial-of-service (DoS) attack. In particular, the malicious attacker is able to erase the data sent to one or more actuators. In order to achieve secure control, we propose a virtual actuator technique under the assumption that the behavior of the attacker has been identified. The main advantage brought by this technique is that the existing components in the control system can be maintained without need of retuning them, since the virtual actuator will perform a reconfiguration of the plant, hiding the attack from the controller point of view. Using Lyapunov-based results that take into account the possible behavior of the attacker, design conditions for calculating the virtual actuators gains are obtained. A numerical example is used to illustrate the proposed secure control strategy.Peer ReviewedPostprint (author's final draft
Spiking Neural Networks for Inference and Learning: A Memristor-based Design Perspective
On metrics of density and power efficiency, neuromorphic technologies have
the potential to surpass mainstream computing technologies in tasks where
real-time functionality, adaptability, and autonomy are essential. While
algorithmic advances in neuromorphic computing are proceeding successfully, the
potential of memristors to improve neuromorphic computing have not yet born
fruit, primarily because they are often used as a drop-in replacement to
conventional memory. However, interdisciplinary approaches anchored in machine
learning theory suggest that multifactor plasticity rules matching neural and
synaptic dynamics to the device capabilities can take better advantage of
memristor dynamics and its stochasticity. Furthermore, such plasticity rules
generally show much higher performance than that of classical Spike Time
Dependent Plasticity (STDP) rules. This chapter reviews the recent development
in learning with spiking neural network models and their possible
implementation with memristor-based hardware
Classical analysis of phase-locking transients and Rabi-type oscillations in microwave-driven Josephson junctions
We present a classical analysis of the transient response of Josephson
junctions perturbed by microwaves and thermal fluctuations. The results include
a specific low frequency modulation in phase and amplitude behavior of a
junction in its zero-voltage state. This transient modulation frequency is
linked directly to an observed variation in the probability for the system to
switch to its non-zero voltage state. Complementing previous work on linking
classical analysis to the experimental observations of Rabi-oscillations, this
expanded perturbation method also provides closed form analytical results for
attenuation of the modulations and the Rabi-type oscillation frequency. Results
of perturbation analysis are compared directly (and quantitatively) to
numerical simulations of the classical model as well as published experimental
data, suggesting that transients to phase-locking are closely related to the
observed oscillations.Comment: 18 pages total, 8 figures (typos corrected; minor revisions to
figures and equations
A Method for the Combination of Stochastic Time Varying Load Effects
The problem of evaluating the probability that a structure becomes unsafe under a
combination of loads, over a given time period, is addressed. The loads and load effects
are modeled as either pulse (static problem) processes with random occurrence time, intensity and a specified shape or intermittent continuous (dynamic problem) processes which
are zero mean Gaussian processes superimposed 'on a pulse process. The load coincidence
method is extended to problems with both nonlinear limit states and dynamic responses,
including the case of correlated dynamic responses. The technique of linearization of a
nonlinear limit state commonly used in a time-invariant problem is investigated for timevarying
combination problems, with emphasis on selecting the linearization point. Results
are compared with other methods, namely the method based on upcrossing rate, simpler
combination rules such as Square Root of Sum of Squares and Turkstra's rule. Correlated
effects among dynamic loads are examined to see how results differ from correlated static
loads and to demonstrate which types of load dependencies are most important, i.e., affect'
the exceedance probabilities the most.
Application of the load coincidence method to code development is briefly discussed.National Science Foundation Grants CME 79-18053 and CEE 82-0759
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