4,472 research outputs found
Systemic Risk and the Role of the Federal Reserve
Considers proposed reforms to reduce systemic risk and makes recommendations on the role of the Federal Reserve, including giving it clear responsibility for monitoring the stability of the financial system and a means of controlling excessive leverage
Challenges of modern capitalism
The future of the U.S. market economy may well be determined by how we resolve three dilemmas: rising income inequality; improving our business culture; and providing important public services.Capitalism
Targeting urban revitalization
A movement to focus public improvement efforts on neighborhoods with the greatest potential to spread the benefits is gaining adherents. Former Federal Reserve Board vice chairman Alice Rivlin discusses her recent research into targeting.Community development
QUALITY, QUANTITY AND TIME ISSUES IN DEMAND FOR VACATIONS
Demand and Price Analysis,
Vision-Based Navigation III: Pose and Motion from Omnidirectional Optical Flow and a Digital Terrain Map
An algorithm for pose and motion estimation using corresponding features in
omnidirectional images and a digital terrain map is proposed. In previous
paper, such algorithm for regular camera was considered. Using a Digital
Terrain (or Digital Elevation) Map (DTM/DEM) as a global reference enables
recovering the absolute position and orientation of the camera. In order to do
this, the DTM is used to formulate a constraint between corresponding features
in two consecutive frames. In this paper, these constraints are extended to
handle non-central projection, as is the case with many omnidirectional
systems. The utilization of omnidirectional data is shown to improve the
robustness and accuracy of the navigation algorithm. The feasibility of this
algorithm is established through lab experimentation with two kinds of
omnidirectional acquisition systems. The first one is polydioptric cameras
while the second is catadioptric camera.Comment: 6 pages, 9 figure
Low-temperature chemistry using the R-matrix method
Techniques for producing cold and ultracold molecules are enabling the study
of chemical reactions and scattering at the quantum scattering limit, with only
a few partial waves contributing to the incident channel, leading to the
observation and even full control of state-to-state collisions in this regime.
A new R-matrix formalism is presented for tackling problems involving low- and
ultra-low energy collisions. This general formalism is particularly appropriate
for slow collisions occurring on potential energy surfaces with deep wells. The
many resonance states make such systems hard to treat theoretically but offer
the best prospects for novel physics: resonances are already being widely used
to control diatomic systems and should provide the route to steering ultracold
reactions. Our R-matrix-based formalism builds on the progress made in
variational calculations of molecular spectra by using these methods to provide
wavefunctions for the whole system at short internuclear distances, (a regime
known as the inner region). These wavefunctions are used to construct collision
energy-dependent R-matrices which can then be propagated to give cross sections
at each collision energy. The method is formulated for ultracold collision
systems with differing numbers of atoms.Comment: Presented at Faraday Discussion on the Theory of Chemical Reactions
Published in Faraday Discussion
Edges of the Barvinok-Novik orbitope
Here we study the k^th symmetric trigonometric moment curve and its convex
hull, the Barvinok-Novik orbitope. In 2008, Barvinok and Novik introduce these
objects and show that there is some threshold so that for two points on S^1
with arclength below this threshold, the line segment between their lifts on
the curve form an edge on the Barvinok-Novik orbitope and for points with
arclenth above this threshold, their lifts do not form an edge. They also give
a lower bound for this threshold and conjecture that this bound is tight.
Results of Smilansky prove tightness for k=2. Here we prove this conjecture for
all k.Comment: 10 pages, 3 figures, corrected Lemma 4 and other minor revision
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