220 research outputs found
Artificial Neurons with Arbitrarily Complex Internal Structures
Artificial neurons with arbitrarily complex internal structure are
introduced. The neurons can be described in terms of a set of internal
variables, a set activation functions which describe the time evolution of
these variables and a set of characteristic functions which control how the
neurons interact with one another. The information capacity of attractor
networks composed of these generalized neurons is shown to reach the maximum
allowed bound. A simple example taken from the domain of pattern recognition
demonstrates the increased computational power of these neurons. Furthermore, a
specific class of generalized neurons gives rise to a simple transformation
relating attractor networks of generalized neurons to standard three layer
feed-forward networks. Given this correspondence, we conjecture that the
maximum information capacity of a three layer feed-forward network is 2 bits
per weight.Comment: 22 pages, 2 figure
Cluster vs Single-Spin Algorithms -- Which are More Efficient?
A comparison between single-cluster and single-spin algorithms is made for
the Ising model in 2 and 3 dimensions. We compare the amount of computer time
needed to achieve a given level of statistical accuracy, rather than the speed
in terms of site updates per second or the dynamical critical exponents. Our
main result is that the cluster algorithms become more efficient when the
system size, , exceeds, -- for and --
for . The exact value of the crossover is dependent upon the computer
being used. The lower end of the crossover range is typical of workstations
while the higher end is typical of vector computers. Hence, even for
workstations, the system sizes needed for efficient use of the cluster
algorithm is relatively large.Comment: 13pages, postscript file, HLRZ 21/9
Non-Blocking Signature of very large SOAP Messages
Data transfer and staging services are common components in Grid-based, or
more generally, in service-oriented applications. Security mechanisms play a
central role in such services, especially when they are deployed in sensitive
application fields like e-health. The adoption of WS-Security and related
standards to SOAP-based transfer services is, however, problematic as a
straightforward adoption of SOAP with MTOM introduces considerable
inefficiencies in the signature generation process when large data sets are
involved. This paper proposes a non-blocking, signature generation approach
enabling a stream-like processing with considerable performance enhancements.Comment: 13 pages, 5 figure
Non-Blocking Signature of very large SOAP Messages
Data transfer and staging services are common components in Grid-based, or
more generally, in service-oriented applications. Security mechanisms play a
central role in such services, especially when they are deployed in sensitive
application fields like e-health. The adoption of WS-Security and related
standards to SOAP-based transfer services is, however, problematic as a
straightforward adoption of SOAP with MTOM introduces considerable
inefficiencies in the signature generation process when large data sets are
involved. This paper proposes a non-blocking, signature generation approach
enabling a stream-like processing with considerable performance enhancements.Comment: 13 pages, 5 figure
Condensation of vortices in the X-Y model in 3d: a disorder parameter
A disorder parameter is constructed which signals the condensation of
vortices. The construction is tested by numerical simulations.Comment: 9 pages, 5 postscript figures, typset using REVTE
Implicit Simulations using Messaging Protocols
A novel algorithm for performing parallel, distributed computer simulations
on the Internet using IP control messages is introduced. The algorithm employs
carefully constructed ICMP packets which enable the required computations to be
completed as part of the standard IP communication protocol. After providing a
detailed description of the algorithm, experimental applications in the areas
of stochastic neural networks and deterministic cellular automata are
discussed. As an example of the algorithms potential power, a simulation of a
deterministic cellular automaton involving 10^5 Internet connected devices was
performed.Comment: 14 pages, 3 figure
Ion Scattering From State-selected Rydberg Atoms
Classical-trajectory Monte Carlo calculations have been performed for collisions of protons with state-selected hydrogenic Rydberg atoms. The examples investigated were Rydberg atoms in the n=10, l=9 level with ml=0 and 9. The collision velocity range was 0.1 to 1.0 a.u. (2.2x107 to 2.2x108 cm/s). The ionization cross sections were found to be relatively insensitive to changes in the ml levels. However, the charge-transfer cross sections showed considerable enhancement if the Rydberg electron is orientated in a plane which is parallel to the direction of the incident projectile. © 1983 The American Physical Society
Non-equilibrium Relaxation Study of Ferromagnetic Transition in Double-Exchange Systems
Ferromagnetic transition in double-exchange systems is studied by
non-equilibrium relaxation technique combined with Monte Carlo calculations.
Critical temperature and critical exponents are estimated from relaxation of
the magnetic moment. The results are consistent with the previous Monte Carlo
results in thermal equilibrium. The exponents estimated by these independent
techniques suggest that the universality class of this transition is the same
as that of short-range interaction models but is different from the mean-field
one.Comment: 3 pages including 1 figure, submitted to J. Phys. Soc. Jp
Vortex Dynamics in Classical Non--Abelian Spin Models
We discuss the abelian vortex dynamics in the abelian projection approach to
non-abelian spin models. We show numerically that in the three-dimensional
SU(2) spin model in the Maximal Abelian projection the abelian off-diagonal
vortices are not responsible for the phase transition contrary to the diagonal
vortices. A generalization of the abelian projection approach to SU(N) spin
models is briefly discussed.Comment: 7 pages, LaTeX, 1 figure, uses epsf.sty; Introduction is extended and
a few references are added; to be published in JETP Let
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