6,574 research outputs found
Automated Problem Decomposition for the Boolean Domain with Genetic Programming
Researchers have been interested in exploring the regularities and modularity of the problem space in genetic programming (GP) with the aim of decomposing the original problem into several smaller subproblems. The main motivation is to allow GP to deal with more complex problems. Most previous works on modularity in GP emphasise the structure of modules used to encapsulate code and/or promote code reuse, instead of in the decomposition of the original problem. In this paper we propose a problem decomposition strategy that allows the use of a GP search to find solutions for subproblems and combine the individual solutions into the complete solution to the problem
Microwave oven fabricated hybrid memristor devices for non-volatile memory storage
© 2014 IOP Publishing Ltd. Novel hybrid non-volatile memories made using an ultra-fast microwave heating method are reported for the first time. The devices, consisting of aligned ZnO nanorods embedded in poly (methyl methacrylate), require no forming step and exhibit reliable and reproducible bipolar resistive switching at low voltages and with low power usage. We attribute these properties to a combination of the high aspect ratio of the nanorods and the polymeric hybrid structure of the device. The extremely easy, fast and low-cost solution based method of fabrication makes possible the simple and quick production of cheap memory cells
Causes of Prolonged Waiting Time in Public Health Facilities among Health Care Seekers in Calabar Municipal Council of Cross River State, Nigeria
The purpose of this study was to investigate the causes of prolonged waiting time in public health care facilities among health care seekers in Calabar Municipal Council of Cross River State, Nigeria. To carry out this investigation, two hypotheses were formulated to guide the study. Survey research design was adopted for this study. A sample of one hundred and eighteen (118) respondents was selected. The selection was done through cluster sampling technique. The questionnaire was the main instrument used for data collection. It was constructed by the researchers with assistance of some measurement experts that gave it face and content validity. The Chi-square (X2) inferential statistics set at 0.05 was used to test the hypothesis. The result shows that there is significant contribution of poor record keeping and inadequate health personnel to the prolonged waiting time in public health care facilities among health care seekers. Based on these findings, some recommendations and suggestions for further studies were made. Keywords: Prolong waiting time; Public health facilities, Health care seekers. Poor record keeping; inadequate health personnel
Reconsidering "the love of art" : evaluating the potential of art museum outreach
Art museums have long been identified as bastions of social and cultural exclusion. This conclusion was best evidenced by the large-scale 1967 French study by Bourdieu and Darbel demonstrating the exclusionary nature of “The Love of Art.” However, in recent years there have been increasing efforts to reach out to a broader range of visitors beyond conventional
audiences. The present study investigates the impacts of an outreach program at a UK art museum, which sought to engage socially excluded young mothers. This study employs ethnographic research methods on a longitudinal basis to develop qualitative insights about the program seeking to mitigate cultural exclusion. While the study’s findings uphold many longstanding critiques of art museums’ conventional approaches, the study also indicates that carefully designed outreach activities can overcome such limitations and enhance cultural
engagement. Thus, art museums’ limited appeal is tied to problematic public engagement practices that can be changed
Experimental Polarization State Tomography using Optimal Polarimeters
We report on the experimental implementation of a polarimeter based on a
scheme known to be optimal for obtaining the polarization vector of ensembles
of spin-1/2 quantum systems, and the alignment procedure for this polarimeter
is discussed. We also show how to use this polarimeter to estimate the
polarization state for identically prepared ensembles of single photons and
photon pairs and extend the method to obtain the density matrix for generic
multi-photon states. State reconstruction and performance of the polarimeter is
illustrated by actual measurements on identically prepared ensembles of single
photons and polarization entangled photon pairs
Integration of the Friedmann equation for universes of arbitrary complexity
An explicit and complete set of constants of the motion are constructed
algorithmically for Friedmann-Lema\^{i}tre-Robertson-Walker (FLRW) models
consisting of an arbitrary number of non-interacting species. The inheritance
of constants of the motion from simpler models as more species are added is
stressed. It is then argued that all FLRW models admit what amounts to a unique
candidate for a gravitational epoch function (a dimensionless scalar invariant
derivable from the Riemann tensor without differentiation which is monotone
throughout the evolution of the universe). The same relations that lead to the
construction of constants of the motion allow an explicit evaluation of this
function. In the simplest of all models, the CDM model, it is shown
that the epoch function exists for all models with , but for
almost no models with .Comment: Final form to appear in Physical Review D1
3D Simulations of MHD Jet Propagation Through Uniform and Stratified External Environments
We present a set of high-resolution 3D MHD simulations of steady light,
supersonic jets, exploring the influence of jet Mach number and the ambient
medium on jet propagation and energy deposition over long distances. The
results are compared to simple self-similar scaling relations for the
morphological evolution of jet-driven structures and to previously published 2D
simulations. For this study we simulated the propagation of light jets with
internal Mach numbers 3 and 12 to lengths exceeding 100 initial jet radii in
both uniform and stratified atmospheres.
The propagating jets asymptotically deposit approximately half of their
energy flux as thermal energy in the ambient atmosphere, almost independent of
jet Mach number or the external density gradient. Nearly one-quarter of the jet
total energy flux goes directly into dissipative heating of the ICM, supporting
arguments for effective feedback from AGNs to cluster media. The remaining
energy resides primarily in the jet and cocoon structures. Despite having
different shock distributions and magnetic field features, global trends in
energy flow are similar among the different models.
As expected the jets advance more rapidly through stratified atmospheres than
uniform environments. The asymptotic head velocity in King-type atmospheres
shows little or no deceleration. This contrasts with jets in uniform media with
heads that are slowed as they propagate. This suggests that the energy
deposited by jets of a given length and power depends strongly on the structure
of the ambient medium. While our low-Mach jets are more easily disrupted, their
cocoons obey evolutionary scaling relations similar to the high-Mach jets.Comment: Accepted in ApJ, 32 pages, 18 figures, animations available from:
http://www.msi.umn.edu/Projects/twj/newsite/projects/radiojets/movies
Interactive public digital displays: investigating its use in a high school context
This paper presents a longitudinal user study that investigated the
adoption of some Bluetooth based functionalities for a public digital display
in a high school. More specifically, the utilization of Bluetooth device naming
extended beyond social identity representation and introduced the use of a
simple interaction mechanism. The interaction mechanism involves recognizing
parts of the Bluetooth device name as explicit instructions to trigger the
generation of content on an interactive public display. Together with representatives
of the teachers' community, the design team defined some social
rules concerning usage in order to account for the specificities of the place. In
the user study, three fully functional prototypes were deployed at the school
hall of the high school. The functionalities introduced with the different prototypes
were: the visualization on the display of the Bluetooth device names,
the possibility to contribute to tag clouds and the possibility to choose icons
from a given set for self-expression. The results suggest that people appropriated
some but not all of the functionalities employed. Implications of our
findings to the design of interactive digital displays are pointed out.(undefined
Validation of mid-infrared spectrometry in milk for predicting body energy status in Holstein-Friesian cows
Yang-Mills fields on CR manifolds
We study pseudo Yang-Mills fields on a compact strictly pseudoconvex CR
manifold.Comment: 52 page
- …