6,102 research outputs found
Central limit theorems for multiple stochastic integrals and Malliavin calculus
We give a new characterization for the convergence in distribution to a
standard normal law of a sequence of multiple stochastic integrals of a fixed
order with variance one, in terms of the Malliavin derivatives of the sequence.
We extend our result to the multidimensional case and prove a weak convergence
result for a sequence of square integrable random variables.Comment: 16 page
The Parallelometer: a mechanical device to study curvature
A simple mechanical device is introduced, the parallelometer, that can be
used to measure curvatures of surfaces. The device can be used as a practical
illustration of parallel transport of a vector and to study Berry phase shift
when it is carried along a loop on the surface. Its connection to the Foucault
pendulum is discussed. The experimental results can be successfully compared
with the theoretical expectations. The experiment is inexpensive and
conceptually easy to perform and understand for a beginner
Rad-hard vertical JFET switch for the HV-MUX system of the ATLAS upgrade Inner Tracker
This work presents a new silicon vertical JFET (V-JFET) device, based on the
trenched 3D-detector technology developed at IMB-CNM, to be used as switches
for the High-Voltage powering scheme of the ATLAS upgrade Inner Tracker. The
optimization of the device characteristics is performed by 2D and 3D TCAD
simulations. Special attention has been paid to the on-resistance and the
switch-off and breakdown voltages to meet the specific requirements of the
system. In addition, a set of parameter values has been extracted from the
simulated curves to implement a SPICE model of the proposed V-JFET transistor.
As these devices are expected to operate under very high radiation conditions
during the whole experiment life-time, a study of the radiation damage effects
and the expected degradation on the device performance is also presented at the
end of the paper.Comment: KEYWORDS: Radiation-hard electronics; Voltage distributions; Large
detector systems for particle and astroparticle physics. 9 Pages, 7 Figure
Sun of Justice Rising: Tonatierra Community Development Institute
Salvador Reza, a longtime organizer for indigenous Mexican rights, helped lead a successful campaign to organize taco vendors in Phoenix. Faced with a local ordinance that would restrict the operation of mobile food stands, effectively banning them, Reza and his colleagues at Tonatierra mobilized the vendors to fight back. Their ultimate success recaptured the spirit of a community traumatized by 500 years of colonization and cultural destruction. Tonatierra's strategies included the following:Involve Vendors: Once vendors understood that the ordinance targeted them and threatened their livelihoods, they were able to establish a working group, representative of the community. They fashioned a way of regulating vendors that would ensure safe food and safe neighborhoods.Create a Team and a United Voice: The vendors negotiated among themselves until they could present their recommendations as a team.Rekindle Culture: According to Reza, "We are fighting back, but not with weapons of guns. Our weapons are culture and understanding and communication.
Space-division multiplexing for fiber-wireless communications
We envision the application of optical Space-division Multiplexing (SDM) to
the next generation fiber-wireless communications as a firm candidate to
increase the end user capacity and provide adaptive radiofrequency-photonic
interfaces. This approach relies on the concept of fiber-distributed signal
processing, where the SDM fiber provides not only radio access distribution but
also broadband microwave photonics signal processing. In particular, we present
two different SDM fiber technologies: dispersion-engineered heterogeneous
multicore fiber links and multicavity devices built upon the selective
inscription of gratings in homogeneous multicore fibers.Comment: 4 pages, 20th International Conference on Transparent Optical
Networks (ICTON), Girona (Spain), 2017. arXiv admin note: text overlap with
arXiv:1810.1213
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