607,405 research outputs found
Identification of changes in hydrological drought characteristics from a multi-GCM driven ensemble constrained by observed discharge
Peer reviewedPublisher PD
The lowest crossing in 2D critical percolation
We study the following problem for critical site percolation on the
triangular lattice. Let A and B be sites on a horizontal line e separated by
distance n. Consider, in the half-plane above e, the lowest occupied crossing R
from the half-line left of A to the half-line right of B. We show that the
probability that R has a site at distance smaller than m from AB is of order
(log (n/m))^{-1}, uniformly in 1 <= m < n/2. Much of our analysis can be
carried out for other two-dimensional lattices as well.Comment: 16 pages, Latex, 2 eps figures, special macros: percmac.tex.
Submitted to Annals of Probabilit
RTNN: The new parallel machine in Zaragoza
I report on the development of RTNN, a parallel computer designed as a 4^4
hypercube of 256 T9000 transputer nodes, each with 8 MB memory. The peak
performance of the machine is expected to be 2.5 Gflops.Comment: 10 pages PostScript, including 5 figures. Write-up (June 1995) of
talk at the International Workshop ``QCD on Massively Parallel Computers'',
Yamagata, Japan, 16-18 March 1995. To appear in the Proceedings, Suppl.
Progr. Theor. Phys. (Kyoto
Compactifications of discrete quantum groups
Given a discrete quantum group A we construct a certain Hopf *-algebra AP
which is a unital *-subalgebra of the multiplier algebra of A. The structure
maps for AP are inherited from M(A) and thus the construction yields a
compactification of A which is analogous to the Bohr compactification of a
locally compact group. This algebra has the expected universal property with
respect to homomorphisms from multiplier Hopf algebras of compact type (and is
therefore unique). This provides an easy proof of the fact that for a discrete
quantum group with an infinite dimensional algebra the multiplier algebra is
never a Hopf algebra
Some views on monopoles and confinement
Aspects of the monopole condensation picture of confinement are discussed.
First, the nature of the monopole singularities in the abelian projection
approach is analysed. Their apparent gauge dependence is shown to have a
natural interpretation in terms of 't~Hooft-Polyakov-like monopoles in
euclidean SU(2) gauge theory. Next, the results and predictions of a
realization of confinement through condensation of such monopoles are
summarized and compared with numerical data.Comment: Talk at the International RCNP Workshop on COLOR CONFINEMENT AND
HADRONS --- CONFINEMENT 95 (March 22--24, 1995, RCNP Osaka, Japan), to appear
in the proceedings. 9 pages latex, 1 PostScript figure in uufiles format,
uses epsf.te
On the standardisation of Web service management operations
Given the current interest in TCP/IP network management research towards Web services, it is important to recognise how standardisation can be achieved. This paper mainly focuses on the standardisation of operations and not management information. We state that standardisation should be done by standardising the abstract parts of a WSDL document, i.e. the interfaces and the messages. Operations can vary in granularity and parameter transparency, creating four extreme operation signatures, all of which have advantages and disadvantages
Marinari-Parisi and Supersymmetric Collective Field Theory
A field theoretic formulation of the Marinari-Parisi supersymmetric matrix
model is established and shown to be equivalent to a recently proposed
supersymmetrization of the bosonic collective string field theory. It also
corresponds to a continuum description of super-Calogero models. The
perturbation theory of the model is developed and, in this approach, an
infinite sequence of vertices is generated. A class of potentials is identified
for which the spectrum is that of a massless boson and Majorana fermion. For
the harmonic oscillator case, the cubic vertices are obtained in an oscillator
basis. For a rather general class of potentials it is argued that one cannot
generate from Marinari-Parisi models a continuum limit similar to that of the
d=1 bosonic string.Comment: 45 page
Lattice Computation of a Magnetic Monopole Mass
A single magnetic monopole in pure SU(2) gauge theory is simulated on the
lattice and its mass is computed in the full quantum theory. The results are
relevant for our proposed realization of the dual superconductor hypothesis of
confinement.Comment: 3 pages PostScript, to appear in the Proceedings of IMACS93 (St.
Louis, USA, Oct. 1993). Registration numbers ITFA-93-38 (Amsterdam),
DFTUZ/93/21 (Zaragoza
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