1,621 research outputs found
Illusion of Control in a Brownian Game
Both single-player Parrondo games (SPPG) and multi-player Parrondo games
(MPPG) display the Parrondo Effect (PE) wherein two or more individually fair
(or Llosing) games yield a net winning outcome if alternated periodically or
randomly. (There is a more formal, less restrictive definition of the PE.) We
illustrate that, when subject to an elementary optimization rule, the PG
displays degraded rather than enhanced returns. Optimization provides only the
illusion of control, when low-entropy strategies (i.e. which use more
information) under-perform random strategies (with maximal entropy). This
illusion is unfortuntately widespread in many human attempts to manage or
predict complex systems. For the PG, the illusion is especially striking in
that the optimization rule reverses an already paradoxical-seeming positive
gain - the Parrondo effect proper - and turns it negative. While this
phenomenon has been previously demonstrated using somewhat artificial
conditions in the MPPG (L. Dinios and J.M.R. Parrondo. Europhysics Letters 63,
319 (2003); J.M.R. Parrondo et al. Advances in Condensed Matter and Statistical
Mechanics, eds. E. Korutcheva and R. Cuerno, Nova Science Publishers, 2003), we
demonstrate it in the natural setting of a history-dependent SPPG.Comment: 8 page with 1 tabl
Quantum Parrondo's Games
Parrondo's Paradox arises when two losing games are combined to produce a
winning one. A history dependent quantum Parrondo game is studied where the
rotation operators that represent the toss of a classical biased coin are
replaced by general SU(2) operators to transform the game into the quantum
domain. In the initial state, a superposition of qubits can be used to couple
the games and produce interference leading to quite different payoffs to those
in the classical case.Comment: LateX, 10 pages, 2 figures, submitted to Physica A special issue
(Gene Stanley Conference, Sicily, 2001), v2 minor correction to equations, v3
corrections to results section and table, acknowledgement adde
Minimal Brownian Ratchet: An Exactly Solvable Model
We develop an exactly-solvable three-state discrete-time minimal Brownian
ratchet (MBR), where the transition probabilities between states are
asymmetric. By solving the master equations we obtain the steady-state
probabilities. Generally the steady-state solution does not display detailed
balance, giving rise to an induced directional motion in the MBR. For a reduced
two-dimensional parameter space we find the null-curve on which the net current
vanishes and detailed balance holds. A system on this curve is said to be
balanced. On the null-curve, an additional source of external random noise is
introduced to show that a directional motion can be induced under the zero
overall driving force. We also indicate the off-balance behavior with biased
random noise.Comment: 4 pages, 4 figures, RevTex source, General solution added. To be
appeared in Phys. Rev. Let
Winning combinations of history-dependent games
The Parrondo effect describes the seemingly paradoxical situation in which
two losing games can, when combined, become winning [Phys. Rev. Lett. 85, 24
(2000)]. Here we generalize this analysis to the case where both games are
history-dependent, i.e. there is an intrinsic memory in the dynamics of each
game. New results are presented for the cases of both random and periodic
switching between the two games.Comment: (6 pages, 7 figures) Version 2: Major cosmetic changes and some minor
correction
The discovery of a low mass, pre-main-sequence stellar association around gamma Velorum
We report the serendipitous discovery of a population of low mass, pre-main
sequence stars (PMS) in the direction of the Wolf-Rayet/O-star binary system
gamma^{2} Vel and the Vela OB2 association. We argue that gamma^{2} Vel and the
low mass stars are truly associated, are approximately coeval and that both are
at distances between 360-490 pc, disagreeing at the 2 sigma level with the
recent Hipparcos parallax of gamma^{2} Vel, but consistent with older distance
estimates. Our results clearly have implications for the physical parameters of
the gamma^{2} Vel system, but also offer an exciting opportunity to investigate
the influence of high mass stars on the mass function and circumstellar disc
lifetimes of their lower mass PMS siblings.Comment: Monthly Notices of the Royal Astronomical Society, Letters - in pres
New paradoxical games based on Brownian ratchets
Based on Brownian ratchets, a counter-intuitive phenomenon has recently
emerged -- namely, that two losing games can yield, when combined, a
paradoxical tendency to win. A restriction of this phenomenon is that the rules
depend on the current capital of the player. Here we present new games where
all the rules depend only on the history of the game and not on the capital.
This new history-dependent structure significantly increases the parameter
space for which the effect operates.Comment: 4 pages, 3 eps figures, revte
A review of stochastic resonance: Circuits and measurement
Copyright © 2002 IEEENoise in dynamical systems is usually considered a nuisance. However, in certain nonlinear systems, including electronic circuits and biological sensory systems, the presence of noise can enhance the detection of weak signals. The phenomenon is termed stochastic resonance and is of great interest for electronic instrumentation. We review and investigate the stochastic resonance of several bistable circuits. A new type of S characteristic circuit is demonstrated using simple nonlinear elements with an operational amplifier. Using this circuit, the effects on stochastic resonance were determined as the slope of the S shaped characteristic curve was varied.Gregory P. Harmer, Bruce R. Davis and Derek Abbot
Human engineering design criteria study Final report
Human engineering design criteria for use in designing earth launch vehicle systems and equipmen
"Illusion of control" in Minority and Parrondo Games
Human beings like to believe they are in control of their destiny. This
ubiquitous trait seems to increase motivation and persistence, and is probably
evolutionarily adaptive. But how good really is our ability to control? How
successful is our track record in these areas? There is little understanding of
when and under what circumstances we may over-estimate or even lose our ability
to control and optimize outcomes, especially when they are the result of
aggregations of individual optimization processes. Here, we demonstrate
analytically using the theory of Markov Chains and by numerical simulations in
two classes of games, the Minority game and the Parrondo Games, that agents who
optimize their strategy based on past information actually perform worse than
non-optimizing agents. In other words, low-entropy (more informative)
strategies under-perform high-entropy (or random) strategies. This provides a
precise definition of the "illusion of control" in set-ups a priori defined to
emphasize the importance of optimization.Comment: 17 pages, four figures, 1 tabl
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