330,676 research outputs found
The boolean map distance: theory and efficient computation
We propose a novel distance function, the boolean map distance (BMD), that defines the distance between two elements in an image based on the probability that they belong to different components after thresholding the image by a randomly selected threshold value. This concept has been explored in a number of recent publications, and has been proposed as an approximation of another distance function, the minimum barrier distance (MBD). The purpose of this paper is to introduce the BMD as a useful distance function in its own right. As such it shares many of the favorable properties of the MBD, while offering some additional advantages such as more efficient distance transform computation and straightforward extension to multi-channel images
Switched Threshold Signatures from K-Private PolyShamir Secret Sharing
Variant secret sharing schemes deriving from Shamir\u27s threshold secret sharing protocol are presented. Results include multi-secret sharing protocols using shares with elements, independent of the number of secrets. The new schemes achieve a weaker notion of security (they\u27re secure rather than strongly secure) but maintain a property called -privacy (inspired by -anonymity). -privacy ensures that all secrets remain private with respect to a subset of the secret space, though the particular subset providing privacy may vary among adversaries that acquire distinct sub-threshold sets of shares. Depending on the number of secrets and the protocol details, secure -private multi-secret sharing schemes may be ``almost\u27\u27 strongly secure or may remain merely secure and -private - a difference captured by the notion of -security. Novel applications of the multi-secret sharing schemes are presented, realising a primitive called a switched threshold signature. Switched threshold signatures have the quirky property that aggregating a threshold number of signatures of one type (e.g. Pointcheval-Sanders signatures) ``switches\u27\u27 the signatures into a master signature of a different type. Collectively these results may permit efficiencies within, e.g., threshold credential issuance protocols
A Model to Forecast the Response of Concrete under Severe Loadings the μ Damage Model
AbstractAmong the “theories” applied to model concrete behavior, damage mechanics has proven to be efficient. One of the first models for concrete introduced within such a framework is Mazars’ damage model. A new formulation of such a model, called the “μ model”, is proposed herein for the purpose of 3D cyclic and dynamic loading, based on a coupling of elasticity and damage within an isotropic formulation. Unilateral behavior (i.e. the opening and closure of cracks) is introduced by the use of two thermodynamic variables. A threshold surface is then associated with each of these variables and strain rate acts on the initial threshold. Applications are presented on plain or reinforced concrete elements subjected to various loading (uni- and multi-axial, cyclic, dynamic). A comparison with experimental results demonstrates the effectiveness of the various selected options
Electroweak Matrix Elements in the Two-Nucleon Sector from Lattice QCD
We demonstrate how to make rigorous predictions for electroweak matrix
elements in nuclear systems directly from QCD. More precisely, we show how to
determine the short-distance contributions to low-momentum transfer electroweak
matrix elements in the two-nucleon sector from lattice QCD. In potential model
descriptions of multi-nucleon systems, this is equivalent to uniquely
determining the meson-exchange currents, while in the context of nuclear
effective field theory, this translates into determining the coefficients of
local, gauge-invariant, multi-nucleon-electroweak current operators. The
energies of the lowest-lying states of two nucleons on a finite volume lattice
with periodic boundary conditions in the presence of a background magnetic
field are sufficient to determine the local four-nucleon operators that
contribute to the deuteron magnetic moment and to the threshold cross-section
of n + p -> d + gamma. Similarly, the energy-levels of two nucleons immersed in
a background isovector axial weak field can be used to determine the
coefficient of the leading local four-nucleon operator contributing to the
neutral- and charged-current break-up of the deuteron. This is required for the
extraction of solar neutrino fluxes at SNO and future neutrino experiments.Comment: 22 pages, 4 figure
Gaugino production in proton-proton collisions at a center-of-mass energy of 8 TeV
Motivated by hints for a light Standard Model-like Higgs boson and a shift in
experimental attention towards electroweak supersymmetry particle production at
the CERN LHC, we update in this paper our precision predictions at
next-to-leading order of perturbative QCD matched to resummation at the
next-to-leading logarithmic accuracy for direct gaugino pair production in
proton-proton collisions with a center-of-mass energy of 8 TeV. Tables of total
cross sections are presented together with the corresponding scale and parton
density uncertainties for benchmark points adopted recently by the experimental
collaborations, and figures are presented for up-to-date model lines attached
to them. Since the experimental analyses are currently obtained with parton
showers matched to multi-parton matrix elements, we also analyze the precision
of this procedure by comparing invariant-mass and transverse-momentum
distributions obtained in this way to those obtained with threshold and
transverse-momentum resummation.Comment: 28 pages, 7 figures, 9 tables; version to appear in JHE
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