3,663 research outputs found
Three-Neutrino MSW Effect and the LNW Mass Matrix
We review recent work on analytical solutions to the MSW equations for three
neutrino flavours, for exponential and linear potentials. An application to a
particular mass matrix is also discussed. The three neutrino masses are
determined, respectively, to be 0.001--0.004, and roughly 0.01 and 0.05 eV.Comment: 7 pages, presented at Scandinavian Neutrino Workshop, Uppsala,
February 8-10, 2001, to appear in the proceedings, Physica Scripta.
Conference info at http://www3.tsl.uu.se/~damet/neutrino/first.htm
Rotation-invariant binary representation of sensor pattern noise for source-oriented image and video clustering
Most existing source-oriented image and video clustering algorithms based on sensor pattern noise (SPN) rely on the pairwise similarities, whose calculation usually dominates the overall computational time. The heavy computational burden is mainly incurred by the high dimensionality of SPN, which typically goes up to millions for delivering plausible clustering performance. This problem can be further aggravated by the uncertainty of the orientation of images or videos because the spatial correspondence between data with uncertain orientations needs to be reestablished in a brute-force search manner. In this work, we propose a rotation-invariant binary representation of SPN to address the issue of rotation and reduce the computational cost of calculating the pairwise similarities. Results on two public multimedia forensics databases have shown that the proposed approach is effective in overcoming the rotation issue and speeding up the calculation of pairwise SPN similarities for source-oriented image and video clustering
Monopoles in Superloop Space
In this paper, we will analyse a four dimensional gauge theory with
supersymmetry in superloop space formalism. We will thus
obtain an expression for the connection in the infinite-dimensional superloop
space. We will then use this connection to obtain an expression for the
curvature of the infinite-dimensional superloop space. We will also show that
this curvature is proportional to the Bianchi identity in spacetime. Thus, in
absence of a monopole this curvature will vanish. However, it will not vanish
if the superloop intersects the world-line of a monopole because the Bianchi
will not hold at that point.Comment: 9 pages, 0 figures, accepted for publication in EP
Color-decoupled photo response non-uniformity for digital image forensics
The last few years have seen the use of photo response non-uniformity noise (PRNU), a unique fingerprint of imaging sensors, in various digital forensic applications such as source device identification, content integrity verification and authentication. However, the use of a colour filter array for capturing only one of the three colour components per pixel introduces colour interpolation noise, while the existing methods for extracting PRNU provide no effective means for addressing this issue. Because the artificial colours obtained through the colour interpolation process is not directly acquired from the scene by physical hardware, we expect that the PRNU extracted from the physical components, which are free from interpolation noise, should be more reliable than that from the artificial channels, which carry interpolation noise. Based on this assumption we propose a Couple-Decoupled PRNU (CD-PRNU) extraction method, which first decomposes each colour channel into 4 sub-images and then extracts the PRNU noise from each sub-image. The PRNU noise patterns of the sub-images are then assembled to get the CD-PRNU. This new method can prevent the interpolation noise from propagating into the physical components, thus improving the accuracy of device identification and image content integrity verification
Inferring causal relations from multivariate time series : a fast method for large-scale gene expression data
Various multivariate time series analysis techniques have been developed with the aim of inferring causal relations between time series. Previously, these techniques have proved their effectiveness on economic and neurophysiological data, which normally consist of hundreds of samples. However, in their applications to gene regulatory inference, the small sample size of gene expression time series poses an obstacle. In this paper, we describe some of the most commonly used multivariate inference techniques and show the potential challenge related to gene expression analysis. In response, we propose a directed partial correlation (DPC) algorithm as an efficient and effective solution to causal/regulatory relations inference on small sample gene expression data. Comparative evaluations on the existing techniques and the proposed method are presented. To draw reliable conclusions, a comprehensive benchmarking on data sets of various setups is essential. Three experiments are designed to assess these methods in a coherent manner. Detailed analysis of experimental results not only reveals good accuracy of the proposed DPC method in large-scale prediction, but also gives much insight into all methods under evaluation
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