6,198 research outputs found
Forms and currents on the analytification of an algebraic variety (after Chambert-Loir and Ducros)
Chambert-Loir and Ducros have recently introduced real differential forms and
currents on Berkovich spaces. In these notes, we survey this new theory and we
will compare it with tropical algebraic geometry.Comment: 25 pages, notes for my survey talk given at the Simons Symposium in
St. John from 1.4-5.4.2013. In the second version, a sign error in the
definition of the integral is corrected and the exposition in section 7 is
slightly change
Video-rate computational super-resolution and integral imaging at longwave-infrared wavelengths
We report the first computational super-resolved, multi-camera integral
imaging at long-wave infrared (LWIR) wavelengths. A synchronized array of FLIR
Lepton cameras was assembled, and computational super-resolution and
integral-imaging reconstruction employed to generate video with light-field
imaging capabilities, such as 3D imaging and recognition of partially obscured
objects, while also providing a four-fold increase in effective pixel count.
This approach to high-resolution imaging enables a fundamental reduction in the
track length and volume of an imaging system, while also enabling use of
low-cost lens materials.Comment: Supplementary multimedia material in
http://dx.doi.org/10.6084/m9.figshare.530302
Efficient Rank Reduction of Correlation Matrices
Geometric optimisation algorithms are developed that efficiently find the
nearest low-rank correlation matrix. We show, in numerical tests, that our
methods compare favourably to the existing methods in the literature. The
connection with the Lagrange multiplier method is established, along with an
identification of whether a local minimum is a global minimum. An additional
benefit of the geometric approach is that any weighted norm can be applied. The
problem of finding the nearest low-rank correlation matrix occurs as part of
the calibration of multi-factor interest rate market models to correlation.Comment: First version: 20 pages, 4 figures Second version [changed content]:
21 pages, 6 figure
Optimal acid rain abatement policy in Europe
Acid rain causes greater environmental damage than would occur if countries act cooperatively. Based on new estimates of sulphur abatement cost functions, the potential gains from cooperation are calculated for Europe. Various cooperative abatement rates are compared with the rates implied by recent international agreements. The distinction is made between primary and secondary abatement, and their respective roles are discussed.Environmental Management; abatement; acid rain; cooperation
An anemometer for measuring velocities on the .25 to 4.25 M/sec range
A vane type anemometer was developed as a secondary standard for the on site calibration of wind velocity sensors. The instrument outputs an electrical pulse for each interruption of a light source by an eight vane fan. The pulse rate is proportional to the fan's angular speed and linearly related to wind velocity over the range 0.25 to 4.27 m/sec
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