77,995 research outputs found
An Ontario Libraries' Network, or Cooperative Entanglement
While I
accepted the invitation to discuss the College Bibliocentre at
this Clinic, I cannot
say that I did so with equanimity. Quite apart from many
organizational difficulties, the systems both in operation and in varying stages
of
development at the College Bibliocentre, have evolved from practical emersion
without the benefit of the finite
planning or initial test and research proce-
dures from
grant aids that many others have experienced. This is why I
adopted the latter part of my title for this paper.
I was asked
particularly to discuss the techniques we are using to
acquire the necessary input to the various systems. However, if I was asked to
underline what I considered to be the
major problems facing the development
of a central technical service unit, the technicalities of how to
input would be
the least concern. The
major problems are those beyond the technological
requirements how to achieve the degree of coordination required and, in
particular, how to overcome the financial hazards which face such an organiza-
tion.published or submitted for publicatio
REGIONAL AND SECTORAL EFFECTS OF COMPETITION FOR WHEAT TRANSPORTATION
Crop Production/Industries,
Failure Rate Computations Based on Mariner Mars 1964 Spacecraft Data
Mariner Mars 1964 failure rates computed for use in reliability predictions and cost allocation
Antibunching in an optomechanical oscillator
We theoretically analyze antibunching of the phonon field in an
optomechanical oscillator employ- ing the membrane-in-the-middle geometry. More
specifically, a single-mode mechanical oscillator is quadratically coupled to a
single-mode cavity field in the regime in which the cavity dissipation is a
dominant source of damping, and adiabatic elimination of the cavity field leads
to an effective cubic nonlinearity for the mechanics. We show analytically in
the weak coupling regime that the mechan- ics displays a chaotic phonon field
for small optomechanical cooperativity, whereas an antibunched single-phonon
field appears for large optomechanical cooperativity. This opens the door to
control of the second-order correlation function of a mechanical oscillator in
the weak coupling regime
Convergence of the restricted Nelder-Mead algorithm in two dimensions
The Nelder-Mead algorithm, a longstanding direct search method for
unconstrained optimization published in 1965, is designed to minimize a
scalar-valued function f of n real variables using only function values,
without any derivative information. Each Nelder-Mead iteration is associated
with a nondegenerate simplex defined by n+1 vertices and their function values;
a typical iteration produces a new simplex by replacing the worst vertex by a
new point. Despite the method's widespread use, theoretical results have been
limited: for strictly convex objective functions of one variable with bounded
level sets, the algorithm always converges to the minimizer; for such functions
of two variables, the diameter of the simplex converges to zero, but examples
constructed by McKinnon show that the algorithm may converge to a nonminimizing
point.
This paper considers the restricted Nelder-Mead algorithm, a variant that
does not allow expansion steps. In two dimensions we show that, for any
nondegenerate starting simplex and any twice-continuously differentiable
function with positive definite Hessian and bounded level sets, the algorithm
always converges to the minimizer. The proof is based on treating the method as
a discrete dynamical system, and relies on several techniques that are
non-standard in convergence proofs for unconstrained optimization.Comment: 27 page
Angular Power Spectra of the COBE DIRBE Maps
The angular power spectra of the infrared maps obtained by the DIRBE (Diffuse
InfraRed Background Experiment) instrument on the COBE satellite have been
obtained by two methods: the Hauser-Peebles method previously applied to the
DMR maps, and by Fourier transforming portions of the all-sky maps projected
onto a plane. The two methods give consistent results, and the power spectrum
of the high-latitude dust emission is C_\ell \propto \ell^{-3} in the range 2 <
\ell < 300.Comment: ApJ in press. 15 pages with 5 included figure
Voltage regulator with plural parallel power source sections Patent
Dissipative voltage regulator system for minimizing heat dissipatio
Can Effects of Dark Matter be Explained by the Turbulent Flow of Spacetime?
For the past forty years the search for dark matter has been one of the
primary foci of astrophysics, although there has yet to be any direct evidence
for its existence (Porter et al. 2011). Indirect evidence for the existence of
dark matter is largely rooted in the rotational speeds of stars within their
host galaxies, where, instead of having a ~ r^1/2 radial dependence, stars
appear to have orbital speeds independent of their distance from the galactic
center, which led to proposed existence of dark matter (Porter et al. 2011;
Peebles 1993). We propose an alternate explanation for the observed stellar
motions within galaxies, combining the standard treatment of a fluid-like
spacetime with the possibility of a "bulk flow" of mass through the Universe.
The differential "flow" of spacetime could generate vorticies capable of
providing the "perceived" rotational speeds in excess of those predicted by
Newtonian mechanics. Although a more detailed analysis of our theory is
forthcoming, we find a crude "order of magnitude" calculation can explain this
phenomena. We also find that this can be used to explain the graviational
lensing observed around globular clusters like "Bullet Cluster".Comment: 5 pages, Accepted for publication in Journal of Modern Physics:
Gravitation and Cosmology (Sept. 2012
A smart vision sensor for detecting risk factors of a toddler's fall in a home environment
This paper presents a smart vision sensor for detecting risk factors of a toddler's fall in an indoor home environment assisting parents' supervision to prevent fall injuries. We identified the risk factors by analyzing real fall injury stories and referring to a related organization's suggestions to prevent falls. In order to detect the risk factors using computer vision, two major image processing methods, clutter detection and toddler tracking, were studied with using only one commercial web-camera. For practical purposes, there is no need for a toddler to wear any sensors or markers. The algorithms for detection have been developed, implemented and tested
- …