584 research outputs found
VAPI: Vectorization of Algorithm for Performance Improvement
This study presents the vectorization of metaheuristic algorithms as the
first stage of vectorized optimization implementation. Vectorization is a
technique for converting an algorithm, which operates on a single value at a
time to one that operates on a collection of values at a time to execute
rapidly. The vectorization technique also operates by replacing multiple
iterations into a single operation, which improves the algorithm's performance
in speed and makes the algorithm simpler and easier to be implemented. It is
important to optimize the algorithm by implementing the vectorization
technique, which improves the program's performance, which requires less time
and can run long-running test functions faster, also execute test functions
that cannot be implemented in non-vectorized algorithms and reduces iterations
and time complexity. Converting to vectorization to operate several values at
once and enhance algorithms' speed and efficiency is a solution for long
running times and complicated algorithms. The objective of this study is to use
the vectorization technique on one of the metaheuristic algorithms and compare
the results of the vectorized algorithm with the algorithm which is
non-vectorized.Comment: 21 page
Application of Variational Principle to Form Reduced Fluid-Structure Interaction Models in Bifurcated Networks
Reduced fluid-structure interaction models have received a considerable attention in recent years being the key component of hemodynamic modeling. A variety of models applying to specific physiological components such as arterial, venous and cerebrospinal fluid (CSF) circulatory systems have been developed based on different approaches. The purpose of this paper is to apply the general approach based on Hamilton’s variational principle to create a model for a viscous Newtonian Fluid - Structure Interaction (FSI) in a compliant bifurcated network. This approach provides the background for a correct formulation of reduced FSI models with an account for arbitrary nonlinear visco-elastic properties of compliant boundaries. The correct boundary conditions are specified at junctions, including the interface between 3D and 1D models. The hyperbolic properties of the derived mathematical model are analyzed and used, constructing a monotone finite volume numerical scheme, second-order accuracy in time and space. The computational algorithm is validated by comparison of numerical solutions with the exact manufactured solutions for an isolated compliant segment and a bifurcated structure. The accuracy of applied total variation diminishing (TVD) and Lax-Wendroff schemes are analyzed by comparison of numerical results to the available analytical smooth and discontinuous solutions, demonstrating a superior performance from the TVD algorithm
Variational Approach of Constructing Reduced Fluid-Structure Interaction Models in Bifurcated Networks
Reduced fluid-structure interaction models have received a considerable attention in recent years being the key component of hemodynamic modeling. A variety of models applying to specific physiological components such as arterial, venous and cerebrospinal fluid (CSF) circulatory systems have been developed based on different approaches. The purpose of this paper is to apply the general approach based on Hamilton’s variational principle to create a model for a viscous Newtonian fluid - structure interaction (FSI) in a compliant bifurcated network. This approach provides the background for a correct formulation of reduced FSI models with an account for arbitrary nonlinear visco-elastic properties of compliant boundaries. The correct boundary conditions are specified at junctions, including matching points in a combined 3D/1D approach. The hyperbolic properties of derived mathematical model are analyzed and used, constructing the monotone finite volume numerical scheme, second-order accuracy in time and space. The computational algorithm is validated by comparison of numerical solutions with the exact manufactured solutions for an isolated compliant segment and a bifurcated structure. The accuracy of applied TVD (total variation diminishing) and Lax-Wendroff methods are analyzed by comparison of numerical results to the available analytical smooth and discontinuous solutions
UV Light-Induced Aggregation of Titania Submicron Particles
In this study, aggregation of TiO2 (rutile and anatase) submicron particles in deionized (DI) water under ultra-violet (UV) light irradiation was investigated. While no aggregation was observed in the dark, rutile and anatase submicron particles started aggregating upon application of UV light and ceased aggregation in about 2 and 8.4 h, respectively. It has been demonstrated that UV light directly mitigated the particle mobility of TiO2, resulting in a neutralization effect of the Zeta potential. It was also observed that rutile particles aggregated much faster than anatase particles under UV radiation, indicating that the Zeta potential of as-prepared rutile is less than that of anatase in deionized (DI) water. In addition, the interaction energy of rutile and anatase particles was simulated using the Derjaguin-Landau-Verwey-Overbeek (DLVO) model. The results showed a significant reduction of barrier energy from 118.2 kBT to 33.6 kBT for rutile and from 333.5 kBT to 46.1 kBT for anatase, respectively, which further validated the remarkable influence of UV irradiation on the aggregation kinetics of rutile and anatase submicron particles. This work presents a further understanding of the aggregation mechanism of light-controlled submicron particles and has a promising potential application in environmental remediation.. © 2016 by the authors
Parents’ Perspectives on Variants of Uncertain Significance from Chromosome Microarray Analysis
Chromosomal microarray analysis (CMA) for unexplained anomalies and developmental delay has improved diagnosis rates, but results classified as variants of uncertain significance (VUS) may challenge both clinicians and families. We explored the impact of such results on families, including parental knowledge, understanding and interpretation. Semi‐structured telephone interviews were conducted with parents (N = 14) who received genetic counseling for a VUS in their child. Transcripts were analyzed through an iterative coding process. Participants demonstrated a range of recall and personal interpretation regarding whether test results provided a causal explanation for their children’s health issues. Participants maintained contradictory interpretations, describing results as answers while maintaining that little clarification of their child’s condition had been provided. Reported benefits included obtaining medical services and personal validation. Parents described adaptation/coping processes similar to those occurring after positive test results. Recall of terminology, including “VUS” and precise CMA abnormalities, was poor. However, most demonstrated conceptual understanding of scientific uncertainty. All participants expressed intentions to return for recommended genetics follow‐up but had misconceptions about how this would occur. These results provide insight into the patient‐and‐family experience when receiving uncertain genomic findings, emphasize the importance of exploring uncertainty during the communication process, and highlight areas for potential attention or improvement in the clinical encounter.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146918/1/jgc40101.pd
Constraints on small-scale cosmological perturbations from gamma-ray searches for dark matter
Events like inflation or phase transitions can produce large density
perturbations on very small scales in the early Universe. Probes of small
scales are therefore useful for e.g. discriminating between inflationary
models. Until recently, the only such constraint came from non-observation of
primordial black holes (PBHs), associated with the largest perturbations.
Moderate-amplitude perturbations can collapse shortly after matter-radiation
equality to form ultracompact minihalos (UCMHs) of dark matter, in far greater
abundance than PBHs. If dark matter self-annihilates, UCMHs become excellent
targets for indirect detection. Here we discuss the gamma-ray fluxes expected
from UCMHs, the prospects of observing them with gamma-ray telescopes, and
limits upon the primordial power spectrum derived from their non-observation by
the Fermi Large Area Space Telescope.Comment: 4 pages, 3 figures. To appear in J Phys Conf Series (Proceedings of
TAUP 2011, Munich
Exploring Parameter Constraints on Quintessential Dark Energy: the Albrecht-Skordis model
We consider the effect of future dark energy experiments on
``Albrecht-Skordis'' (AS) models of scalar field dark energy using the
Monte-Carlo Markov chain method. We deal with the issues of parameterization of
these models, and have included spatial curvature as a parameter, finding it to
be important. We use the Dark Energy Task Force (DETF) simulated data to
represent future experiments and report our results in the form of likelihood
contours in the chosen parameter space. Simulated data is produced for cases
where the background cosmology has a cosmological constant, as well as cases
where the dark energy is provided by the AS model. The latter helps us
demonstrate the power of DETF Stage 4 data in the context of this specific
model. Though the AS model can produce equations of state functions very
different from what is possible with the parametrization used by the
DETF, our results are consistent with those reported by the DETF.Comment: 7 pages, including 9 figure
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