5,200 research outputs found
The application of user log for online business environment using content-based Image retrieval system
Over the past few years, inter-query learning has gained much attention in the research and development of content-based image retrieval (CBIR) systems. This is largely due to the capability of inter-query approach to enable learning from the retrieval patterns of previous query sessions. However, much of the research works in this field have been focusing on analyzing image retrieval patterns stored in the database. This is not suitable for a dynamic environment such as the World Wide Web (WWW) where images are constantly added or removed. A better alternative is to use an image's visual features to capture the knowledge gained from the previous query sessions. Based on the previous work (Chung et al., 2006), the aim of this paper is to propose a framework of inter-query learning for the WWW-CBIR systems. Such framework can be extremely useful for those online companies whose core business involves providing multimedia content-based services and products to their customers
Information entropy in fragmenting systems
The possibility of facing critical phenomena in nuclear fragmentation is a
topic of great interest. Different observables have been proposed to identify
such a behavior, in particular, some related to the use of information entropy
as a possible signal of critical behavior. In this work we critically examine
some of the most widespread used ones comparing its performance in bond
percolation and in the analysis of fragmenting Lennard Jones Drops.Comment: 3 pages, 3 figure
On localization in holomorphic equivariant cohomology
We prove a localization formula for a "holomorphic equivariant cohomology"
attached to the Atiyah algebroid of an equivariant holomorphic vector bundle.
This generalizes Feng-Ma, Carrell-Liebermann, Baum-Bott and K. Liu's
localization formulas.Comment: 16 pages. Completely rewritten, new title. v3: Minor changes in the
exposition. v4: final version to appear in Centr. Eur. J. Mat
Imaging-Based Patient-Specific Biomechanical Evaluation of Atherosclerosis and Aneurysm: A Comparison Between Structural-Only, Fluid-Only and Fluid–Structure Interaction Analysis
Cardiovascular diseases (CVD) are the leading cause of morbidity and mortality worldwide. Atherosclerosis is the dominating underlying cause of CVD, that occurs at susceptible locations such as coronary and carotid arteries. The progression of atherosclerosis is a gradual process and most of the time asymptomatic until a catastrophic event occurs. Similarly, an intracranial aneurysm is the bulging of the cerebral artery due to a weakened area of the vessel wall. The progression of the aneurysm could result in the rupture of the vessel wall leading to a subarachnoid haemorrhage. The formation and progression of atherosclerosis and aneurysm are closely linked to abnormal blood flow behaviour and mechanical forces acting on the vessel wall. Recent technologies in medical imaging, modeling, and computation are used to estimate critical parameters from patient-specific data. However, there is still a need to develop protocols that are reproducible and efficient. This article focuses on the methods for biomechanical analysis of the cerebral aneurysms and atherosclerotic arteries including carotid & coronary. In this study, patient-specific 3D models were reconstructed from optical coherence imaging (OCT) for coronary and magnetic resonance imaging (MRI) for the carotid and cerebral arteries. The reconstructed models were used for computational fluid dynamics (CFD), structural-only, and fluid–structure interaction (FSI) simulations. The results of the FSI were compared against structural and CFD-only simulations to identify the most suitable method for each artery. The comparison between FSI and structural only simulations for the coronary artery showed similar mechanical stress values across the cardiac cycle with a maximum difference of 1.8%. However, the results for the carotid and cerebral arteries showed a maximum difference of 5% and 20% respectively. Additionally, with relation to the hemodynamic WSS calculated from FSI and CFD-only, the coronary artery presented a significant difference of 87%. Conversely, the results for the carotid and cerebral arteries showed a maximum difference of 9 and 6.4% at systole. Based on the results it can be concluded that the shape & location of the artery will influence the selection of the model that can be used for solving the numerical problem
Cosmological constraints on the generalized holographic dark energy
We use the Markov ChainMonte Carlo method to investigate global constraints
on the generalized holographic (GH) dark energy with flat and non-flat universe
from the current observed data: the Union2 dataset of type supernovae Ia
(SNIa), high-redshift Gamma-Ray Bursts (GRBs), the observational Hubble data
(OHD), the cluster X-ray gas mass fraction, the baryon acoustic oscillation
(BAO), and the cosmic microwave background (CMB) data. The most stringent
constraints on the GH model parameter are obtained. In addition, it is found
that the equation of state for this generalized holographic dark energy can
cross over the phantom boundary wde =-1.Comment: 14 pages, 5 figures. arXiv admin note: significant text overlap with
arXiv:1105.186
Resonant and anti-resonant frequency dependence of the effective parameters of metamaterials
We present a numerical study of the electromagnetic response of the
metamaterial elements that are usedto construct materials with negative
refractive index. For an array of split ring resonators (SRR) we find that the
resonant behavior of the effective magnetic permeability is accompanied by an
anti-resonant behavior of the effective permittivity. In addition, the
imaginary parts of the effective permittivity and permeability are opposite in
sign. We also observe an identical resonant versus anti-resonant frequency
dependence of the effective materials parameters for a periodic array of thin
metallic wires with cuts placed periodically along the length of the wire, with
roles of the permittivity and permeability reversed from the SRR case. We show
in a simple manner that the finite unit cell size is responsible for the
anti-resonant behavior
Bagchi's Theorem for families of automorphic forms
We prove a version of Bagchi's Theorem and of Voronin's Universality Theorem
for family of primitive cusp forms of weight and prime level, and discuss
under which conditions the argument will apply to general reasonable family of
automorphic -functions.Comment: 15 page
Hawking radiation of scalar particles from accelerating and rotating black holes
Hawking radiation of uncharged and charged scalars from accelerating and
rotating black holes is studied. We calculate the tunneling probabilities of
these particles from the rotation and acceleration horizons of these black
holes. Using the tunneling method we recover the correct Hawking temperature as
well
- …