2,958 research outputs found
Scaling properties of delay times in one-dimensional random media
The scaling properties of the inverse moments of Wigner delay times are
investigated in finite one-dimensional (1D) random media with one channel
attached to the boundary of the sample. We find that they follow a simple
scaling law which is independent of the microscopic details of the random
potential. Our theoretical considerations are confirmed numerically for systems
as diverse as 1D disordered wires and optical lattices to microwave waveguides
with correlated scatterers.Comment: 5 pages, 4 figures Submitted to Physical Review B Revision 2: 1)
Theoretical curve fits added to Figures 1-4. 2) Scaling parameter
added to inset of Figure 2. 3) Minor text changes to reflect
referee comments. 4) Some extra refereces were adde
Expected exponential loss for gaze-based video and volume ground truth annotation
Many recent machine learning approaches used in medical imaging are highly
reliant on large amounts of image and ground truth data. In the context of
object segmentation, pixel-wise annotations are extremely expensive to collect,
especially in video and 3D volumes. To reduce this annotation burden, we
propose a novel framework to allow annotators to simply observe the object to
segment and record where they have looked at with a \$200 eye gaze tracker. Our
method then estimates pixel-wise probabilities for the presence of the object
throughout the sequence from which we train a classifier in semi-supervised
setting using a novel Expected Exponential loss function. We show that our
framework provides superior performances on a wide range of medical image
settings compared to existing strategies and that our method can be combined
with current crowd-sourcing paradigms as well.Comment: 9 pages, 5 figues, MICCAI 2017 - LABELS Worksho
Scattering at the Anderson transition: Power--law banded random matrix model
We analyze the scattering properties of a periodic one-dimensional system at
criticality represented by the so-called power-law banded random matrix model
at the metal insulator transition. We focus on the scaling of Wigner delay
times and resonance widths . We found that the typical values of
and (calculated as the geometric mean) scale with the system
size as and , where is the information dimension and is the
correlation dimension of eigenfunctions of the corresponding closed system.Comment: 6 pages, 8 figure
Mesoscopic mean-field theory for spin-boson chains in quantum optical systems
We present a theoretical description of a system of many spins strongly coupled to a bosonic chain. We rely on the use of a spin-wave theory describing the Gaussian fluctuations around the mean-field solution, and focus on spin-boson chains arising as a generalization of the Dicke Hamiltonian. Our model is motivated by experimental setups such as trapped ions, or atoms/qubits coupled to cavity arrays. This situation corresponds to the cooperative (E⊗β) Jahn-Teller distortion studied in solid-state physics. However, the ability to tune the parameters of the model in quantum optical setups opens up a variety of novel intriguing situations. The main focus of this paper is to review the spin-wave theoretical description of this problem as well as to test the validity of mean-field theory. Our main result is that deviations from mean-field effects are determined by the interplay between magnetic order and mesoscopic cooperativity effects, being the latter strongly size-dependent
«Y de estas escogí catorce»: la versión española de las «Novelle» de Bandello
In this article we unravel the reasons why Vincent de Millis translated Matteo Bandello’s Novelle (1554) from the French translation of Pierre Boaistuau and François de Belleforest; how he manipulated the source text and what changes separate the Historias trágicas ejemplares (1589) from the Histoires tragiques (1559) and the Novelle. To do so, we focus on the comparison of some particularly violent scenes and their denouements, a true sample of the strategies used by Boaistuau, Belleforest, and Millis, to carry out the truculent adaptation of the Italian material to the new context where they write and translate.A lo largo del presente artículo intentaremos desgranar las razones por las que Vicente de Millis tradujo las Novelle (1554) de Matteo Bandello a partir de la traducción francesa de Pierre Boaistuau y François de Belleforest; de qué manera manipuló el texto de partida y qué cambios separan las Historias trágicas ejemplares (1589) de las Histoires tragiques (1559) y las Novelle. Para ello, nos centraremos en el cotejo de algunas escenas particularmente violentas y sus desenlaces, verdadero muestrario de las estrategias utilizadas por Boaistuau, Belleforest y, finalmente, Millis, para la adaptación truculenta de la materia italiana al nuevo contexto desde el que escriben y traducen.
SJM: Un simulador de jerarquías de memoria orientado a la docencia de arquitectura de computadores
El concepto de jerarquía de memoria de un computador
es uno de los más importantes en el ámbito de
la docencia en arquitectura de computadores. Habitualmente,
los distintos aspectos de la estructura y el
funcionamiento de la jerarquía de memoria (memoria
cache, memoria virtual, algoritmos de reemplazo,
tasas de fallos, etc.) se explican primero a los alumnos
de manera teórica, y posteriormente se realizan
prácticas basadas en programas que simulan dicha
jerarquía.
En este trabajo se presenta un nuevo simulador pedagógico,
SJM, que permite modelar de forma amigable
distintas jerarquías de memoria, modificar fácilmente
sus características y obtener medidas de sus
prestaciones, de cara a que los alumnos, mediante
la evaluación de distintas configuraciones de la jerarquía
de memoria, afiancen su comprensión de los
distintos aspectos de ésta.Peer Reviewe
Laboratory Characterization and Astrophysical Detection of Vibrationally Excited States of Vinyl Cyanide in Orion-KL
New laboratory data of CHCHCN (vinyl cyanide) in its ground and
vibrationally excited states at the microwave to THz domain allow searching for
these excited state transitions in the Orion-KL line survey.
Frequency-modulated spectrometers combined into a single broadband 50-1900 GHz
spectrum provided measurements of CHCHCN covering a spectral range of
18-1893 GHz, whose assignments was confirmed by Stark modulation spectra in the
18-40 GHz region and by ab-initio anharmonic force field calculations. For
analyzing the emission lines of CHCHCN species detected in Orion-KL we used
the excitation and radiative transfer code (MADEX) at LTE conditions. The
rotational transitions of the ground state of this molecule emerge from four
cloud components of hot core nature which trace the physical and chemical
conditions of high mass star forming regions in the Orion-KL Nebula. The total
column density of CHCHCN in the ground state is (3.00.9)x10
cm. We report on the first interstellar detection of transitions in the
v10=1/(v11=1,v15=1) dyad in space, and in the v11=2 and v11=3 states in
Orion-KL. The lowest energy vibrationally excited states of vinyl cyanide such
as v11=1 (at 328.5 K), v15=1 (at 478.6 K), v11=2 (at 657.8 K), the
v10=1/(v11=1,v15=1) dyad (at 806.4/809.9 K), and v11=3 (at 987.9 K) are
populated under warm and dense conditions, so they probe the hottest parts of
the Orion-KL source. Column density and rotational and vibrational temperatures
for CHCHCN in their ground and excited states, as well as for the
isotopologues, have been constrained by means of a sample of more than 1000
lines in this survey. Moreover, we present the detection of methyl isocyanide
(CHNC) for the first time in Orion-KL and a tentative detection of vinyl
isocyanide (CHCHNC) and give column density ratios between the cyanide and
isocyanide isomers.Comment: 46 pages, 22 figures, 14 tables, 9 online table
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