13,644 research outputs found

    Signals of Unparticles in Low Energy Parity Violation and NuTeV Experiment

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    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 δ(ΔRNRP)\delta(\Delta\frac{R_N}{R_P}) is less than a few times 10410^{-4} 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 (ΛU\Lambda_{\cal U}, dUd_{\cal U}, cVUc_{V{\cal U}} and cAUc_{A{\cal U}}), 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 bsγb\to s\gammaComment: 19 pages, 7 figure

    Challenges of Primary Frequency Control and Benefits of Primary Frequency Response Support from Electric Vehicles

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    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

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    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

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    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

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    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

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    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

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    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 innerinner-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 notnot 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 1/1/\hbar factor (below (3.2)
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