27,133 research outputs found
Power and cross-power spectrum analysis by hybrid computers
Power and cross power spectrum analysis by hybrid computer
Diversity and Adaptation in Large Population Games
We consider a version of large population games whose players compete for
resources using strategies with adaptable preferences. The system efficiency is
measured by the variance of the decisions. In the regime where the system can
be plagued by the maladaptive behavior of the players, we find that diversity
among the players improves the system efficiency, though it slows the
convergence to the steady state. Diversity causes a mild spread of resources at
the transient state, but reduces the uneven distribution of resources in the
steady state.Comment: 8 pages, 3 figure
New explicit spike solution -- non-local component of the generalized Mixmaster attractor
By applying a standard solution-generating transformation to an arbitrary
vacuum Bianchi type II solution, one generates a new solution with spikes
commonly observed in numerical simulations. It is conjectured that the spike
solution is part of the generalized Mixmaster attractor.Comment: Significantly revised. Colour figures simplified to accommodate
non-colour printin
Optical studies of carrier and phonon dynamics in Ga_{1-x}Mn_{x}As
We present a time-resolved optical study of the dynamics of carriers and
phonons in Ga_{1-x}Mn_{x}As layers for a series of Mn and hole concentrations.
While band filling is the dominant effect in transient optical absorption in
low-temperature-grown (LT) GaAs, band gap renormalization effects become
important with increasing Mn concentration in Ga_{1-x}Mn_{x}As, as inferred
from the sign of the absorption change. We also report direct observation on
lattice vibrations in Ga1-xMnxAs layers via reflective electro-optic sampling
technique. The data show increasingly fast dephasing of LO phonon oscillations
for samples with increasing Mn and hole concentration, which can be understood
in term of phonon scattering by the holes.Comment: 13 pages, 3 figures replaced Fig.1 after finding a mistake in
previous versio
Late-time behaviour of the tilted Bianchi type VI models
We study tilted perfect fluid cosmological models with a constant equation of
state parameter in spatially homogeneous models of Bianchi type VI
using dynamical systems methods and numerical simulations. We study models with
and without vorticity, with an emphasis on their future asymptotic evolution.
We show that for models with vorticity there exists, in a small region of
parameter space, a closed curve acting as the attractor.Comment: 13 pages, 1 figure, v2: typos fixed, minor changes, matches published
versio
Daylight performance through different types of glazing in the tropics
Having glazing on buildings will allow natural daylighting in a room. There are four types of glazing which are commonly used in the market today: Clear, light green, bronze and black float glass where tinted glazing will provide shading to the interior. These four glass are being tested using Integrated Environmental Solutions Virtual Environment (IESVE) software with different proportion to investigate the influence of arrangements of glazing to permit daylight and to serve as shading device. There are 40 combinations of different glazing proportion tested in the simulation. The combination of 75 % clear float glass on a green float glass base gives the highest lux value at a point 90cm from the opening whereas the lowest value is exhibited through a 25% green float glass with a black float glass base of 75%. The finding shows that glazing with lower Visual Light Transmittance as the base will give a lower Daylight Factor compared to using it on top of the other glazing. Furthermore, although there is a large contrast of Daylight Factor between the 0.9m and 3.6m depth, several combination of glazing achieved the requirement of Malaysian Standard 1525 for daylighting in office
Edge detection based on morphological amoebas
Detecting the edges of objects within images is critical for quality image
processing. We present an edge-detecting technique that uses morphological
amoebas that adjust their shape based on variation in image contours. We
evaluate the method both quantitatively and qualitatively for edge detection of
images, and compare it to classic morphological methods. Our amoeba-based
edge-detection system performed better than the classic edge detectors.Comment: To appear in The Imaging Science Journa
Using hospital readmission rates to track the quality of care in public hospitals in Singapore
Understanding different types of consumers: A multi-group analysis based on convenience food-related lifestyle
The primary objective of this study is to identify categories of organic food consumers based on the CFL (convenience food related lifestyle). Secondarily, this study explores characteristics, motivations/barriers in consumption and perception regarding to self-focus perception (such as perceived consequence of purchasing organic food) and altruistic behaviour (such as recycling behavior and perception of transportation) in different CFL. 1,262 valid samples are collected in this study. Moderate, convenience-pursuing and quality-pursuing categories are separated by cluster analysis. Consumer attitudes toward ready-made meals and takeaway meal solutions, perceived consequences of purchasing organic food, purchase frequency and quantity are differential, and the influence of organic food purchasing perception of consequence on altruistic behaviour are differences in CFL. Only consumers who purchase organic food motivated by environmental concerns are able to improve their recycling behavior. This study believes that the CFL framework has enhanced the understanding of consumer buying behavior and characteristics
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