5,646 research outputs found
A High-Fidelity Realization of the Euclid Code Comparison -body Simulation with Abacus
We present a high-fidelity realization of the cosmological -body
simulation from the Schneider et al. (2016) code comparison project. The
simulation was performed with our Abacus -body code, which offers high force
accuracy, high performance, and minimal particle integration errors. The
simulation consists of particles in a box,
for a particle mass of with $10\
h^{-1}\mathrm{kpc}z=0<0.3\%k<10\
\mathrm{Mpc}^{-1}h0.01\%$. Simulation snapshots are available at
http://nbody.rc.fas.harvard.edu/public/S2016 .Comment: 13 pages, 8 figures. Minor changes to match MNRAS accepted versio
Optimizing Gas Mixture Composition for the RTPC Detector for BONuS 12 at Jefferson Lab.
The main objective of this thesis is to perform a study of and optimize the most direct and practical gas mixture composition inside the Radial Time Projection Chamber for the Barely-Offshell Nucleon Structure (BONuS 12) detector for use in the CLAS 12 detector in Experimental Hall B at Thomas Jefferson National Accelerator Facility (JLab). The optimization of these conditions will enhance the performance and resolution of the detector. The original BONuS 6 experiment utilized a gas composition of 80 % He and 20% Dimethyl Ether (DME). With the extensive 12 GeV energy upgrade constructed at JLab and the new BONuS 12 detector established , it is imperative that the gas composition utilized, is best suited to facilitate the experimental needs and demands. BONuS 12 is an experiment designed to measure the momentum of recoiling spectator protons down to 70 MeV/c. This technique will extract the structure function Fn 2 at large x from 0.1 up to 0.8 over a significant range in Q2 and W from the nucleon mass, with a beam energy of 11 GeV, enabling us to essentially select free neutrons
A high-performance data structure for mobile information systems
Mobile information systems can now be provided on small form-factor computers. Dictionary-based data compression extends the capabilities of systems with limited processing and memory to enable data intensive applications to be supported in such environments. The nature of judicial sentencing decisions requires that a support system provides accurate and up-to-date data and is compatible with the professional working experience of a judge. The difficulties caused by mobility and the data dependence of the decision-making process are addressed by an Internet-based architecture for collecting and distributing system data.We describe an approach to dictionary-based data compression and the structure of an information system that makes use of this technology
Reactive Quenching Of Od A (2)Σ(+) By H-2: Translational Energy Distributions For H- And D-Atom Product Channels
The H- and D-atom products from collisional quenching of OD A (2)Sigma(+) by H-2 are characterized through Doppler spectroscopy using two-photon (2 S-2 \u3c-\u3c- 1 S-2) laser-induced fluorescence. Partial deuteration enables separation of the channel forming H + HOD products, which accounts for 75% of reactive quenching events, from the D + H2O product channel. The Doppler profiles, along with those reported previously for other isotopic variants, are transformed into product translational energy distributions using a robust fitting procedure based on discrete velocity basis functions. The product translational energy distribution for the H- atom channel is strongly peaked at low energy (below 0.5 eV) with a long tail extending to the energetic limit. By contrast, the D-atom channel exhibits a small peak at low translational energy with a distinctive secondary peak at higher translational energy (approximately 1.8 eV) before falling off to higher energy. In both cases, most of the available energy flows into internal excitation of the water products. Similar distributions are obtained upon reanalysis of D- and H- atom Doppler profiles, respectively, from reactive quenching of OH A (2)Sigma(+) by D-2. The sum of the translational energy distributions for H- and D- atom channels is remarkably similar to that obtained for OH A (2)Sigma(+) + H-2, where the two channels cannot be distinguished from one another. The product translational energy distributions from reactive quenching are compared with those obtained from a previous experiment performed at higher collision energy, quasiclassical trajectory calculations of the post-quenching dynamics, and a statistical model. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3644763
The Abacus Cosmos: A Suite of Cosmological N-body Simulations
We present a public data release of halo catalogs from a suite of 125
cosmological -body simulations from the Abacus project. The simulations span
40 CDM cosmologies centered on the Planck 2015 cosmology at two mass
resolutions, and , in and
boxes, respectively. The boxes are phase-matched to
suppress sample variance and isolate cosmology dependence. Additional volume is
available via 16 boxes of fixed cosmology and varied phase; a few boxes of
single-parameter excursions from Planck 2015 are also provided. Catalogs
spanning to are available for friends-of-friends and Rockstar
halo finders and include particle subsamples. All data products are available
at https://lgarrison.github.io/AbacusCosmosComment: 13 pages, 9 figures, 3 tables. Additional figures added for mass
resolution convergence tests, and additional redshifts added for existing
tests. Matches ApJS accepted versio
Punctuated Equilibrium in Software Evolution
The approach based on paradigm of self-organized criticality proposed for
experimental investigation and theoretical modelling of software evolution. The
dynamics of modifications studied for three free, open source programs Mozilla,
Free-BSD and Emacs using the data from version control systems. Scaling laws
typical for the self-organization criticality found. The model of software
evolution presenting the natural selection principle is proposed. The results
of numerical and analytical investigation of the model are presented. They are
in a good agreement with the data collected for the real-world software.Comment: 4 pages, LaTeX, 2 Postscript figure
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