10,371 research outputs found
Dilaton Stabilization and Inflation in the D-brane World
We study the dilaton stabilization in the D-brane world in which a D-brane
constitutes our universe. The dilaton can be stabilized due to the interplay
between the D-brane tension and the negative scalar curvature of extra
dimensions. Cosmic evolution of the dilaton is investigated with the obtained
dilaton potential and it is found that inflation can be realized before the
settlement of the dilaton.Comment: 10 pages, abstract correcte
Neutron and muon-induced background studies for the AMoRE double-beta decay experiment
AMoRE (Advanced Mo-based Rare process Experiment) is an experiment to search
a neutrinoless double-beta decay of Mo in molybdate crystals. The
neutron and muon-induced backgrounds are crucial to obtain the zero-background
level (< counts/(keVkgyr)) for the AMoRE-II experiment,
which is the second phase of the AMoRE project, planned to run at YEMI
underground laboratory. To evaluate the effects of neutron and muon-induced
backgrounds, we performed Geant4 Monte Carlo simulations and studied a
shielding strategy for the AMORE-II experiment. Neutron-induced backgrounds
were also included in the study. In this paper, we estimated the background
level in the presence of possible shielding structures, which meet the
background requirement for the AMoRE-II experiment
A V-Diagram for the Design of Integrated Health Management for Unmanned Aerial Systems
Designing Integrated Vehicle Health Management (IVHM) for Unmanned Aerial Systems (UAS) is inherently complex. UAS are a system of systems (SoS) and IVHM is a product-service, thus the designer has to take into account many factors, such as: the design of the other systems of the UAS (e.g. engines, structure, communications), the split of functions between elements of the UAS, the intended operation/mission of the UAS, the cost verses benefit of monitoring a system/component/part, different techniques for monitoring the health of the UAS, optimizing the health of the fleet and not just the individual UAS, amongst others. The design of IVHM cannot sit alongside, or after, the design of UAS, but itself be integrated into the overall design to maximize IVHM’s potential.
Many different methods exist to help design complex products and manage the process. One method used is the V-diagram which is based on three concepts: decomposition & definition; integration & testing; and verification & validation. This paper adapts the V-diagram so that it can be used for designing IVHM for UAS. The adapted v-diagram splits into different tracks for the different system elements of the UAS and responses to health states (decomposition and definition). These tracks are then combined into an overall IVHM provision for the UAS (integration and testing), which can be verified and validated. The stages of the adapted V-diagram can easily be aligned with the stages of the V-diagram being used to design the UAS bringing the design of the IVHM in step with the overall design process. The adapted V-diagram also allows the design IVHM for a UAS to be broken down in to smaller tasks which can be assigned to people/teams with the relevant competencies. The adapted V-diagram could also be used to design IVHM for other SoS and other vehicles or products
Four-point functions and kaon decays in a minimal AdS/QCD model
We study the predictions of holographic QCD for various observable four-point
quark flavour current-current correlators. The dual 5-dimensional bulk theory
we consider is a Yang Mills theory in a slice of
spacetime with boundaries. Particular UV and IR boundary conditions
encode the spontaneous breaking of the dual 4D global chiral symmetry down to
the subgroup. We explain in detail how to calculate the 4D four-point
quark flavour current-current correlators using the 5D holographic theory,
including interactions. We use these results to investigate predictions of
holographic QCD for the rule for kaon decays and the
parameter. The results agree well in comparison with experimental data, with an
accuracy of 25% or better. The holographic theory automatically includes the
contributions of the meson resonances to the four-point correlators. The
correlators agree well in the low-momentum and high-momentum limit, in
comparison with chiral perturbation theory and perturbative QCD results,
respectively.Comment: Published version, title changed to conform with Journal format,
references and clarifying remarks added, 40 pages, 5 figure
Definition of valid proteomic biomarkers: a bayesian solution
Clinical proteomics is suffering from high hopes generated by reports on apparent biomarkers, most of which could not be later substantiated via validation. This has brought into focus the need for improved methods of finding a panel of clearly defined biomarkers. To examine this problem, urinary proteome data was collected from healthy adult males and females, and analysed to find biomarkers that differentiated between genders. We believe that models that incorporate sparsity in terms of variables are desirable for biomarker selection, as proteomics data typically contains a huge number of variables (peptides) and few samples making the selection process potentially unstable. This suggests the application of a two-level hierarchical Bayesian probit regression model for variable selection which assumes a prior that favours sparseness. The classification performance of this method is shown to improve that of the Probabilistic K-Nearest Neighbour model
Adhesion Induced DNA Naturation
DNA adsorption and naturation is modeled via two interacting flexible
homopolymers coupled to a solid surface. DNA denatures if the entropy gain for
unbinding the two strands overcomes the loss of binding energy. When adsorbed
to a surface, the entropy gain is smaller than in the bulk, leading to a
stronger binding and, upon neglecting self-avoidance, absence of a denatured
phase. Now consider conditions where the binding potentials are too weak for
naturation, and the surface potential too weak to adsorb single strands. In a
variational approach it is shown that their combined action may lead to a
naturated adsorbed phase. Conditions for the absence of naturation and
adsorption are derived too. The phase diagram is constructed qualitatively.Comment: 4 pages, 1 figur
High Energy Physics from High Performance Computing
We discuss Quantum Chromodynamics calculations using the lattice regulator.
The theory of the strong force is a cornerstone of the Standard Model of
particle physics. We present USQCD collaboration results obtained on Argonne
National Lab's Intrepid supercomputer that deepen our understanding of these
fundamental theories of Nature and provide critical support to frontier
particle physics experiments and phenomenology.Comment: Proceedings of invited plenary talk given at SciDAC 2009, San Diego,
June 14-18, 2009, on behalf of the USQCD collaboratio
Extending the Real-Time Maude Semantics of Ptolemy to Hierarchical DE Models
This paper extends our Real-Time Maude formalization of the semantics of flat
Ptolemy II discrete-event (DE) models to hierarchical models, including modal
models. This is a challenging task that requires combining synchronous
fixed-point computations with hierarchical structure. The synthesis of a
Real-Time Maude verification model from a Ptolemy II DE model, and the formal
verification of the synthesized model in Real-Time Maude, have been integrated
into Ptolemy II, enabling a model-engineering process that combines the
convenience of Ptolemy II DE modeling and simulation with formal verification
in Real-Time Maude.Comment: In Proceedings RTRTS 2010, arXiv:1009.398
Stability Of contact discontinuity for steady Euler System in infinite duct
In this paper, we prove structural stability of contact discontinuities for
full Euler system
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