8,207 research outputs found
On Asynchronous Session Semantics
This paper studies a behavioural theory of the π-calculus with session types under the fundamental principles of the practice of distributed computing — asynchronous communication which is order-preserving inside each connection (session), augmented with asynchronous inspection of events (message arrivals). A new theory of bisimulations is introduced, distinct from either standard
asynchronous or synchronous bisimilarity, accurately capturing the semantic nature of session-based asynchronously communicating processes augmented with
event primitives. The bisimilarity coincides with the reduction-closed barbed congruence. We examine its properties and compare them with existing semantics.
Using the behavioural theory, we verify that the program transformation of multithreaded into event-driven session based processes, using Lauer-Needham duality,
is type and semantic preserving
Fractal boundary basins in spherically symmetric theory
Results are presented from numerical simulations of the flat-space nonlinear
Klein-Gordon equa- tion with an asymmetric double-well potential in spherical
symmetry. Exit criteria are defined for the simulations that are used to help
understand the boundaries of the basins of attraction for Gaussian "bubble"
initial data. The first exit criteria, based on the immediate collapse or
expan- sion of bubble radius, is used to observe the departure of the scalar
field from a static intermediate attractor solution. The boundary separating
these two behaviors in parameter space is smooth and demonstrates a
time-scaling law with an exponent that depends on the asymmetry of the
potential. The second exit criteria differentiates between the creation of an
expanding true-vacuum bubble and dispersion of the field leaving the false
vacuum; the boundary separating these basins of attraction is shown to
demonstrate fractal behavior. The basins are defined by the number of bounces
that the field undergoes before inducing a phase transition. A third, hybrid
exit criteria is used to determine the location of the boundary to arbitrary
precision and to characterize the threshold behavior. The possible effects this
behavior might have on cosmological phase transitions are briefly discussed.Comment: 10 pages, 13 figures, 1 movie, resubmitted with additional paragraph.
Matches published versio
Fluidic proportional thruster for SPARCS 4
Design, development, fabrication, and acceptance test results for two fluidic proportional thrusters for use in SPARCS
An Introduction to Pervasive Interface Automata
Pervasive systems are often context-dependent, component based systems in which components expose interfaces and offer one or more services. These systems may evolve in unpredictable ways, often through component replacement. We present pervasive interface automata as a formalism for modelling components and their composition. Pervasive interface automata are based on the interface automata of Henzinger et al, with several significant differences. We expand their notion of input and output actions to combinations of input, output actions, and callable methods and method calls. Whereas interfaces automata have a refinement relation, we argue the crucial relation in pervasive systems is component replacement, which must include consideration of the services offered by a component and assumptions about the environment. We illustrate pervasive interface autmotata and component replacement with a small case study of a pervasive application for sports predictions
A new type of solution of the Schr\"odinger equation on a self-similar fractal potential
Scattering a quantum particle by a self-similar fractal potential on a Cantor
set is investigated. We present a new type of solution of the functional
equation for the transfer matrix of this potential, which was derived earlier
from the Schr\"odinger equation.Comment: Latex, 4 pages, 7 eps-figures; the old figures are renewed and new
ones are adde
Covariation Among Vowel Height Effects on Acoustic Measures
Covariation among vowel height effects on vowel intrinsic fundamental frequency (IF0), voice onset time (VOT), and voiceless interval duration (VID) is analyzed to assess the plausibility of a common physiological mechanism underlying variation in these measures. Phrases spoken by 20 young adults, containing words composed of initial voiceless stops or /s/ and high or low vowels, were produced in habitual and voluntarily increased F0 conditions. High vowels were associated with increased IF0 and longer VIDs. VOT and VID exhibited significant covariation with IF0 only for males at habitua
Examining the Geometrical Model with Inverted Mass Hierarchy for Neutrinos
The comprehensive analyses are presented in the model with the inverted mass
hierarchy for neutrinos, which follows from a geometrical structure of a (1+5)
dimensional space-time where two extra dimensions are compactified on the
T^2/Z_3 orbifold. The model gives two large lepton flavor mixings due to the S3
structure in the (1+5) dimensional space-time. It also predicts the lightest
neutrino mass as m_3=(1-50)\times 10^{-5}eV and the effective neutrino mass
responsible for neutrinoless double beta decays as _{ee}\simeq 50 meV. The
low energy CP violation, J_{CP} could be 0.02. On the other hand, the observed
baryon asymmetry in the present universe is produced by the non-thermal
leptogenesis, which works even at the reheating temperature
TR=10^{4}-10^{6}GeV. The correlation between the baryon asymmetry and the low
energy CP violation is examined in this model.Comment: 17 pages, 10 figures, a reference is added, minor change in
introductio
Fluidic Proportional Thruster System Final Report
Fluidic proportional thrust control system with vortex valve
Nucleosynthesis Modes in the High-Entropy-Wind of Type II Supernovae: Comparison of Calculations with Halo-Star Observations
While the high-entropy wind (HEW) of Type II supernovae remains one of the
more promising sites for the rapid neutron-capture (r-) process, hydrodynamic
simulations have yet to reproduce the astrophysical conditions under which the
latter occurs. We have performed large-scale network calculations within an
extended parameter range of the HEW, seeking to identify or to constrain the
necessary conditions for a full reproduction of all r-process residuals
N_{r,\odot}=N_{\odot}-N_{s,\odot} by comparing the results with recent
astronomical observations. A superposition of weighted entropy trajectories
results in an excellent reproduction of the overall N_{r,\odot}-pattern beyond
Sn. For the lighter elements, from the Fe-group via Sr-Y-Zr to Ag, our HEW
calculations indicate a transition from the need for clearly different sources
(conditions/sites) to a possible co-production with r-process elements,
provided that a range of entropies are contributing. This explains recent
halo-star observations of a clear non-correlation of Zn and Ge and a weak
correlation of Sr - Zr with heavier r-process elements. Moreover, new
observational data on Ru and Pd seem to confirm also a partial correlation with
Sr as well as the main r-process elements (e.g. Eu).Comment: 15 pages, 1 table, 4 figures; To be published in the Astrophysical
Journal Letter
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