66,103 research outputs found
Comprehensive Spectral Analysis of Human EEG GENERATORS in Posterior Cerebral Regions
Human electroencephalogram generator spectral analysis in posterior cerebral region
Transition from antibunching to bunching in cavity QED
The photon statistics of the light emitted from an atomic ensemble into a
single field mode of an optical cavity is investigated as a function of the
number of atoms. The light is produced in a Raman transition driven by a pump
laser and the cavity vacuum [M.Hennrich et al., Phys. Rev. Lett. 85, 4672
(2000)], and a recycling laser is employed to repeat this process continuously.
For weak driving, a smooth transition from antibunching to bunching is found
for about one intra-cavity atom. Remarkably, the bunching peak develops within
the antibunching dip. For saturated driving and a growing number of atoms, the
bunching amplitude decreases and the bunching duration increases, indicating
the onset of Raman lasing.Comment: 4 pages, 4 figure
Keyed Non-Parametric Hypothesis Tests
The recent popularity of machine learning calls for a deeper understanding of
AI security. Amongst the numerous AI threats published so far, poisoning
attacks currently attract considerable attention. In a poisoning attack the
opponent partially tampers the dataset used for learning to mislead the
classifier during the testing phase.
This paper proposes a new protection strategy against poisoning attacks. The
technique relies on a new primitive called keyed non-parametric hypothesis
tests allowing to evaluate under adversarial conditions the training input's
conformance with a previously learned distribution . To do so we
use a secret key unknown to the opponent.
Keyed non-parametric hypothesis tests differs from classical tests in that
the secrecy of prevents the opponent from misleading the keyed test
into concluding that a (significantly) tampered dataset belongs to
.Comment: Paper published in NSS 201
Probing the radial temperature structure of protoplanetary disks with Herschel/HIFI
Herschel/HIFI spectroscopic observations of CO J=10-9, CO J=16-15 and [CII]
towards HD 100546 are presented. The objective is to resolve the velocity
profile of the lines to address the emitting region of the transitions and
directly probe the distribution of warm gas in the disk. The spectra reveal
double-peaked CO line profiles centered on the systemic velocity, consistent
with a disk origin. The J=16-15 line profile is broader than that of the J=10-9
line, which in turn is broader than those of lower J transitions (6-5, 3-2,
observed with APEX), thus showing a clear temperature gradient of the gas with
radius. A power-law flat disk model is used to fit the CO line profiles and the
CO rotational ladder simultaneously, yielding a temperature of T_0=1100 \pm 350
K (at r_0 = 13 AU) and an index of q=0.85 \pm 0.1 for the temperature radial
gradient. This indicates that the gas has a steeper radial temperature gradient
than the dust (mean q_{dust} ~ 0.5), providing further proof of the thermal
decoupling of gas and dust at the disk heights where the CO lines form. The
[CII] line profile shows a strong single-peaked profile red-shifted by 0.5 km
s-1 compared to the systemic velocity. We conclude that the bulk of the [CII]
emission has a non-disk origin (e.g., remnant envelope or diffuse cloud).Comment: Accepted for publication in ApJ
- …