2,264 research outputs found
Limit processes for TASEP with shocks and rarefaction fans
We consider the totally asymmetric simple exclusion process (TASEP) with
two-sided Bernoulli initial condition, i.e., with left density rho_- and right
density rho_+. We consider the associated height function, whose discrete
gradient is given by the particle occurrences. Macroscopically one has a
deterministic limit shape with a shock or a rarefaction fan depending on the
values of rho_{+/-}. We characterize the large time scaling limit of the
fluctuations as a function of the densities rho_{+/-} and of the different
macroscopic regions. Moreover, using a slow decorrelation phenomena, the
results are extended from fixed time to the whole space-time, except along the
some directions (the characteristic solutions of the related Burgers equation)
where the problem is still open.
On the way to proving the results for TASEP, we obtain the limit processes
for the fluctuations in a class of corner growth processes with external
sources, of equivalently for the last passage time in a directed percolation
model with two-sided boundary conditions. Additionally, we provide analogous
results for eigenvalues of perturbed complex Wishart (sample covariance)
matrices.Comment: 46 pages, 3 figures, LaTeX; Extended explanations in the first two
section
Convergence of the two-point function of the stationary TASEP
We consider the two-point function of the totally asymmetric simple exclusion
process with stationary initial conditions. The two-point function can be
expressed as the discrete Laplacian of the variance of the associated height
function. The limit of the distribution function of the appropriately scaled
height function was obtained previously by Ferrari and Spohn. In this paper we
show that the convergence can be improved to the convergence of moments. This
implies the convergence of the two-point function in a weak sense along the
near-characteristic direction as time tends to infinity, thereby confirming the
conjecture in the paper of Ferrari and Spohn.Comment: LaTeX, 18 pages, 2 figures; Minor correction
RegPT: Direct and fast calculation of regularized cosmological power spectrum at two-loop order
We present a specific prescription for the calculation of cosmological power
spectra, exploited here at two-loop order in perturbation theory (PT), based on
the multi-point propagator expansion. In this approach power spectra are
constructed from the regularized expressions of the propagators that reproduce
both the resummed behavior in the high-k limit and the standard PT results at
low-k. With the help of N-body simulations, we show that such a construction
gives robust and accurate predictions for both the density power spectrum and
the correlation function at percent-level in the weakly non-linear regime. We
then present an algorithm that allows accelerated evaluations of all the
required diagrams by reducing the computational tasks to one-dimensional
integrals. This is achieved by means of pre-computed kernel sets defined for
appropriately chosen fiducial models. The computational time for two-loop
results is then reduced from a few minutes, with the direct method, to a few
seconds with the fast one. The robustness and applicability of this method are
tested against the power spectrum cosmic emulator from which a wide variety of
cosmological models can be explored. The fortran program with which direct and
fast calculations of power spectra can be done, RegPT, is publicly released as
part of this paper.Comment: 28 pages, 15 figure
Corrigendum: Limit Process of Stationary TASEP near the Characteristic Line
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/96244/1/21439_ftp.pd
New frontiers in calcium stable isotope geochemistry:Perspectives in present and past vertebrate biology
International audienc
Design life cycle of a 3-D printed hydrocyclone
Abstract: In mineral processing solid-fluid mixtures are separated in various ways. Of these, hydrocyclones are found to be a simple and low cost technique for particle separation. Additive Manufacturing (AM) technology has the potential to improve the design and testing process for hydrocyclones. The aim of this study is to evaluate the effectiveness of using AM and surface treatments to optimise hydrocyclone design. The hydrocyclone used in these experiments is based on a commercial model used in practice. The hydrocyclone was manufactured with a common plastic material (ABS+) and was fabricated by use a Rapid Prototyping Additive Manufacturing (RPAM) technique. This paper describes the 3-D design printing (3DDP) and manufacture of a hydrocyclone design based on a commercial design using RPAM and a surface protection process. Based on the results of this study, this process has the potential to reduce development time and cost to produce an optimal hydrocyclone design iteration
Teaching and assessing systems thinking in engineering
This paper presents research on undergraduate engineering students’ perceptions of their learning about systems thinking
Optimal quantization for the pricing of swing options
In this paper, we investigate a numerical algorithm for the pricing of swing
options, relying on the so-called optimal quantization method. The numerical
procedure is described in details and numerous simulations are provided to
assert its efficiency. In particular, we carry out a comparison with the
Longstaff-Schwartz algorithm.Comment: 27
Emotion and Time Perception: Effects of Film-Induced Mood
Previous research into emotion and time perception has been designed to study the time perception of emotional events themselves (e.g., facial expression). Our aim was to investigate the effect of emotions per se on the subsequent time judgment of a neutral, non-affective event. In the present study, the participants were presented with films inducing a specific mood and were subsequently given a temporal bisection task. More precisely, the participants were given two temporal bisection tasks, one before and the other after viewing the emotional film. Three emotional films were tested: one eliciting fear, another sadness, and a neutral control film. In addition, the direct mood experience was assessed using the Brief Mood Introspective Scale that was administered to the participants at the beginning and the end of the session. The results showed that the perception of time did not change after viewing either the neutral control films or the sad films although the participants reported being sadder and less aroused after than before watching the sad film clips. In contrast, the stimulus durations were judged longer after than before viewing the frightening films that were judged to increase the emotion of fear and arousal level. In combination with findings from previous studies, our data suggest that the selective lengthening effect after watching frightening films was mediated by an effect of arousal on the speed of the internal clock system
- …