18,659 research outputs found
A mechanism for randomness
We investigate explicit functions that can produce truly random numbers. We
use the analytical properties of the explicit functions to show that certain
class of autonomous dynamical systems can generate random dynamics. This
dynamics presents fundamental differences with the known chaotic systems. We
present realphysical systems that can produce this kind of random time-series.
We report theresults of real experiments with nonlinear circuits containing
direct evidence for this new phenomenon. In particular, we show that a
Josephson junction coupled to a chaotic circuit can generate unpredictable
dynamics. Some applications are discussed.Comment: Accepted in Physics Letters A (2002). 11 figures (.eps
Another approach to Runge-Kutta methods
The condition equations are derived by the introduction of a system of equivalent differential equations, avoiding the usual formalism with trees and elementary differentials. Solutions to the condition equations are found by direct optimization, avoiding the necessity to introduce simplifying assumptions upon the Runge-Kutta coefficients. More favourable coefficients, in view of rounding errors, are found
Competition and boundary formation in heterogeneous media: Application to neuronal differentiation
We analyze an inhomogeneous system of coupled reaction-diffusion equations
representing the dynamics of gene expression during differentiation of nerve
cells. The outcome of this developmental phase is the formation of distinct
functional areas separated by sharp and smooth boundaries. It proceeds through
the competition between the expression of two genes whose expression is driven
by monotonic gradients of chemicals, and the products of gene expression
undergo local diffusion and drive gene expression in neighboring cells. The
problem therefore falls in a more general setting of species in competition
within a non-homogeneous medium. We show that in the limit of arbitrarily small
diffusion, there exists a unique monotonic stationary solution, which splits
the neural tissue into two winner-take-all parts at a precise boundary point:
on both sides of the boundary, different neuronal types are present. In order
to further characterize the location of this boundary, we use a blow-up of the
system and define a traveling wave problem parametrized by the position within
the monotonic gradient: the precise boundary location is given by the unique
point in space at which the speed of the wave vanishes
Synchronicity From Synchronized Chaos
The synchronization of loosely coupled chaotic oscillators, a phenomenon
investigated intensively for the last two decades, may realize the
philosophical notion of synchronicity. Effectively unpredictable chaotic
systems, coupled through only a few variables, commonly exhibit a predictable
relationship that can be highly intermittent. We argue that the phenomenon
closely resembles the notion of meaningful synchronicity put forward by Jung
and Pauli if one identifies "meaningfulness" with internal synchronization,
since the latter seems necessary for synchronizability with an external system.
Jungian synchronization of mind and matter is realized if mind is analogized to
a computer model, synchronizing with a sporadically observed system as in
meteorological data assimilation. Internal synchronization provides a recipe
for combining different models of the same objective process, a configuration
that may also describe the functioning of conscious brains. In contrast to
Pauli's view, recent developments suggest a materialist picture of
semi-autonomous mind, existing alongside the observed world, with both
exhibiting a synchronistic order. Basic physical synchronicity is manifest in
the non-local quantum connections implied by Bell's theorem. The quantum world
resides on a generalized synchronization "manifold", a view that provides a
bridge between nonlocal realist interpretations and local realist
interpretations that constrain observer choice .Comment: 1) clarification regarding the connection with philosophical
synchronicity in Section 2 and in the concluding section 2) reference to
Maldacena-Susskind "ER=EPR" relation in discussion of role of wormholes in
entanglement and nonlocality 3) length reduction and stylistic changes
throughou
Enabling a Pepper Robot to provide Automated and Interactive Tours of a Robotics Laboratory
The Pepper robot has become a widely recognised face for the perceived
potential of social robots to enter our homes and businesses. However, to date,
commercial and research applications of the Pepper have been largely restricted
to roles in which the robot is able to remain stationary. This restriction is
the result of a number of technical limitations, including limited sensing
capabilities, and have as a result, reduced the number of roles in which use of
the robot can be explored. In this paper, we present our approach to solving
these problems, with the intention of opening up new research applications for
the robot. To demonstrate the applicability of our approach, we have framed
this work within the context of providing interactive tours of an open-plan
robotics laboratory.Comment: 8 pages, Submitted to IROS 2018 (2018 IEEE/RSJ International
Conference on Intelligent Robots and Systems), see
https://bitbucket.org/pepper_qut/ for access to the softwar
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