13,860 research outputs found
Signals of Unparticles in Low Energy Parity Violation and NuTeV Experiment
We have studied the possible signals of unparticle in atomic parity
violation(APV) along an isotope chain and in the NuTeV experiment. The effects
of unparticle physics could be observed in APV, if the uncertainty in relative
neutron/proton radius shift is less than a few
times by measuring the parity violating electron scattering. The
constraints imposed by NuTeV experiment on unparticle physics are discussed in
detail. If the NuTeV results are confirmed by future experiments, we suggest
that unparticle could account for a part of NuTeV anomaly. There exist certain
regions for the unparticle parameters (, ,
and ), where the NuTeV discrepancy could be
completely explained by unparticle effects and the strange quark asymmetry,
even with or without the contributions from the isoscalarity violation etc. It
is remarkable that these parameter regions are consistent with the constraints
from Comment: 19 pages, 7 figure
Challenges of Primary Frequency Control and Benefits of Primary Frequency Response Support from Electric Vehicles
As the integration of wind generation displaces conventional plants, system inertia provided by rotating mass declines, causing concerns over system frequency stability. This paper implements an advanced stochastic scheduling model with inertia-dependent fast frequency response requirements to investigate the challenges on the primary frequency control in the future Great Britain electricity system. The results suggest that the required volume and the associated cost of primary frequency response increase significantly along with the increased capacity of wind plants. Alternative measures (e.g. electric vehicles) have been proposed to alleviate these concerns. Therefore, this paper also analyses the benefits of primary frequency response support from electric vehicles in reducing system operation cost, wind curtailment and carbon emissions
Visualizing Convolutional Networks for MRI-based Diagnosis of Alzheimer's Disease
Visualizing and interpreting convolutional neural networks (CNNs) is an
important task to increase trust in automatic medical decision making systems.
In this study, we train a 3D CNN to detect Alzheimer's disease based on
structural MRI scans of the brain. Then, we apply four different gradient-based
and occlusion-based visualization methods that explain the network's
classification decisions by highlighting relevant areas in the input image. We
compare the methods qualitatively and quantitatively. We find that all four
methods focus on brain regions known to be involved in Alzheimer's disease,
such as inferior and middle temporal gyrus. While the occlusion-based methods
focus more on specific regions, the gradient-based methods pick up distributed
relevance patterns. Additionally, we find that the distribution of relevance
varies across patients, with some having a stronger focus on the temporal lobe,
whereas for others more cortical areas are relevant. In summary, we show that
applying different visualization methods is important to understand the
decisions of a CNN, a step that is crucial to increase clinical impact and
trust in computer-based decision support systems.Comment: MLCN 201
Supersolvability and Freeness for ψ-Graphical Arrangements
Let G be a simple graph on the vertex set {v[subscript 1],…,v[subscript n]} with edge set E. Let K be a field. The graphical arrangement A[subscript G] in K[superscript n] is the arrangement x[subscript i]−x[subscript j]=0,v[subscript i]v[subscript j] ∈ E. An arrangement A is supersolvable if the intersection lattice L(c(A)) of the cone c(A) contains a maximal chain of modular elements. The second author has shown that a graphical arrangement A[subscript G] is supersolvable if and only if G is a chordal graph. He later considered a generalization of graphical arrangements which are called ψ-graphical arrangements. He conjectured a characterization of the supersolvability and freeness (in the sense of Terao) of a ψ-graphical arrangement. We provide a proof of the first conjecture and state some conditions on free ψ-graphical arrangements.China Scholarship CouncilNational Science Foundation (U.S.) (Grant DMS-1068625
Entropy and Its Quantum Thermodynamical Implication for Anomalous Spectral Systems
The state function entropy and its quantum thermodynamical implication for
two typical dissipative systems with anomalous spectral densities are studied
by investigating on their low-temperature quantum behavior. In all cases it is
found that the entropy decays quickly and vanishes as the temperature
approaches zero. This reveals a good conformity with the third law of
thermodynamics and provides another evidence for the validity of fundamental
thermodynamical laws in the quantum dissipative region.Comment: 10 pages, 3 figure
Efficient distributed information fusion using value of information based censoring
In many distributed sensing applications, not all agents have valuable information
at all times. Therefore, requiring all agents to communicate at all times can be
resource intensive. In this work, the notion of Value of Information (VoI) is used to
improve the efficiency of distributed sensing algorithms. Particularly, only agents
with high VoI broadcast their measurements to the network, while others censor
their measurements. New VoI realized data fusion algorithms are introduced, and
an in depth analysis of the costs incurred by these algorithms and conventional
distributed data fusion algorithms is presented. Numerical simulations are used
to compare the performance of the VoI realized algorithms with traditional data
fusion algorithms. A VoI based algorithm that adaptively adjusts the criterion for
being informative is presented and shown to strike a good balance between reduced
communication cost and increased accuracy.United States. Army Research Office (MURI grant W911NF-11-1-0391
BTZ Black Hole with Gravitational Chern-Simons: Thermodynamics and Statistical Entropy
Recently, the BTZ black hole in the presence of the gravitational
Chern-Simons (GCS) term has been studied and it has been found that the usual
thermodynamical quantities, like as the black hole mass, angular momentum, and
black hole entropy, are modified. But, for large values of the GCS coupling,
where the modification terms dominate the original terms, some exotic behaviors
occur, like as the roles of the mass and angular momentum are interchanged and
the black hole entropy depends more on the -horizon area than the outer
one. A basic physical problem of this system is that the form of entropy does
not guarantee the second law of thermodynamics, in contrast to the
Bekenstein-Hawking (BH) entropy. Moreover, this entropy does agree with
the statistical entropy, in contrast to a good agreement for small values of
the GCS coupling. Here I find that there is another entropy formula where the
usual BH form dominates the inner-horizon term again, as in the small GCS
coupling, such as the second law of thermodynamics can be guaranteed. I compare
the result of the holographic approach with the classical-
symmetry-algebra-based approach and I find exact agreements even with the
higher-derivative term of GCS. This provides a non-trivial check of the
AdS/CFT-correspondence in the presence of higher-derivative terms in the
gravity action.Comment: Accepted in Phys. Rev. D; Shortened version, Raised a new question of
the validity of the first law (No. 5 in Sec.5), Clarified the relation with
the Euclidean action approach for factor (below (3.2)
- …