22,558 research outputs found
Pipes and Connections
This document describes the low-level Pipe and ConnectionManager objects of the Mesh-
Router system. The overall MeshRouter framework provides a general scheme for interest-
limited communications among a number of client processes. This generality is achieved by
a carefully factorized, object-oriented software implementation. Within this framework, the
Pipe and ConnectionManager (base) classes dened in this note specify the interfaces for i) ac-
tual `bits on the wire' communications and ii) dynamic client insertions during overall system
execution. Two specic implementations of the Pipe class are described in detail: a `Memo-
ryPipe' linking objects instanced on a single processor and a more general 'rtisPipe' providing
inter-processor communications built entirely from the standard RTI-s library used in current
JSAF applications. Initialization procedures within the overall MeshRouter system are dis-
cussed, with particular attention given to dynamic management of inter-processor connections.
Prototype RTI-s router processes are discussed, and simple extensions of the standard system
conguration data les are presented
Test of shell-model interactions for nuclear structure calculations
The binding energy and excitation spectra of 6Li are calculated in a no-core shell-model space giving encouraging results. The results of this calculation are then treated as a theoretical experiment, against which different effective-interaction approximations are compared. In this way insight into the perturbation expansion for the effective interaction is obtained
Universality of Decay out of Superdeformed Bands in the 190 Mass Region
Superdeformed nuclei in the 190 mass region exhibit a striking universality
in their decay-out profiles. We show that this universality can be explained in
the two-level model of superdeformed decay as related to a strong separation of
energy scales: a higher scale related to the nuclear interactions, and a lower
scale caused by electromagnetic decay. Furthermore, we present the results of
the two-level model for all decays for which sufficient data are known,
including statistical extraction of the matrix element for tunneling through
the potential barrier.Comment: 7 pages, 3 figures. v2: some minor clarifications, minor correction
to Fig.
Development and evaluation of a device to simulate a sonic boom
A device to simulate the vibrational and acoustical properties of a sonic boom was developed and evaluated. The design employed a moving circular diaphragm which produced pressure variations by altering the volume of an air-tight enclosure that was located adjacent to an acoustical test chamber. A review of construction oriented problems, along with their solutions, is presented. The simulator is shown to produce the effects of sonic booms having pressure signatures with rise times as low as 5 milliseconds, durations as short as 80 milliseconds, and overpressures as high as 2.5 pounds per square foot. Variations in the signatures are possible by independent adjustments of the simulator. The energy spectral density is also shown to be in agreement with theory and with actual measurements for aircraft
Statistical Dynamics of Religions and Adherents
Religiosity is one of the most important sociological aspects of populations.
All religions may evolve in their beliefs and adapt to the society
developments. A religion is a social variable, like a language or wealth, to be
studied like any other organizational parameter.
Several questions can be raised, as considered in this study: e.g. (i) from a
``macroscopic'' point of view : How many religions exist at a given time? (ii)
from a ``microscopic'' view point: How many adherents belong to one religion?
Does the number of adherents increase or not, and how? No need to say that if
quantitative answers and mathematical laws are found, agent based models can be
imagined to describe such non-equilibrium processes.
It is found that empirical laws can be deduced and related to preferential
attachment processes, like on evolving network; we propose two different
algorithmic models reproducing as well the data. Moreover, a population
growth-death equation is shown to be a plausible modeling of evolution dynamics
in a continuous time framework. Differences with language dynamic competition
is emphasized.Comment: submitted to EP
Manifestation of three-body forces in f7/2-shell nuclei
The traditional nuclear shell model approach is extended to include many-body
forces. The empirical Hamiltonian with a three-body force is constructed for
the identical nucleons on the 0f7/2 shell. Manifestations of the three-body
force in spectra, binding energies, seniority mixing, particle-hole symmetry,
electromagnetic and particle transition rates are investigated. It is shown
that in addition to the usual expansion of the valence space within the
tranditional two-body shell model, the three-body component in the Hamiltonian
can be an important part improving the quality of the theoretical approach.Comment: 5 pages, 1 figur
Effective interactions for light nuclei: an effective (field theory) approach
One of the central open problems in nuclear physics is the construction of
effective interactions suitable for many-body calculations. We discuss a
recently developed approach to this problem, where one starts with an effective
field theory containing only fermion fields and formulated directly in a
no-core shell-model space. We present applications to light nuclei and to
systems of a few atoms in a harmonic-oscillator trap. Future applications and
extensions, as well as challenges, are also considered
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