Dynamic model of fiber bundles

A realistic continuous-time dynamics for fiber bundles is introduced and studied both analytically and numerically. The equation of motion reproduces known stationary-state results in the deterministic limit while the system under non-vanishing stress always breaks down in the presence of noise. Revealed in particular is the characteristic time evolution that the system tends to resist the stress for considerable time, followed by sudden complete rupture. The critical stress beyond which the complete rupture emerges is also obtained

Constituent quark model for nuclear stopping in high energy nuclear collisions

We study the nuclear stopping in high energy nuclear collisions using the constituent quark model. It is assumed that wounded nucleons with different number of interacted quarks hadronize in different ways. The probabilities of having such wounded nucleons are evaluated for proton-proton, proton-nucleus and nucleus-nucleus collisions. After examining our model in proton-proton and proton-nucleus collisions and fixing the hadronization functions, it is extended to nucleus-nucleus collisions. It is used to calculate the rapidity distribution and the rapidity shift of final state protons in nucleus-nucleus collisions. The computed results are in good agreement with the experimental data on ^{32}\mbox{S} +\ ^{32}\mbox{S} at $E_{lab} = 200$ AGeV and ^{208}\mbox{Pb} +\ ^{208}\mbox{Pb} at $E_{lab} = 160$ AGeV. Theoretical predictions are also given for proton rapidity distribution in ^{197}\mbox{Au} +\ ^{197}\mbox{Au} at $\sqrt{s} = 200$ AGeV (BNL-RHIC). We predict that the nearly baryon free region will appear in the midrapidity region and the rapidity shift is $\langle \Delta y \rangle = 2.22$.Comment: 40 pages, 16 Postscript figures, submitted to Phys. Rev.

Planning the digitisation, storage and access of large scale audiovisual archives

This paper presents ongoing work in PrestoSpace on how broadcast archives can plan large-scale, long-term digitization and storage projects. In our approach, carrier decay, technical obsolescence, and rapidly falling costs of mass storage are represented as a series of statistical and predictive models. The models include ongoing migration within a digital archive. The objective is to allow archive managers to investigate the trade-offs between how many items to transfer, the cost of transfer and storage, how long it will take, what quality can be achieved, how much will be lost, and what digital storage solutions to adopt over time. The process and models are based on digitization projects conducted by large broadcast archives that are currently migrating their collections into digital form. Whilst our focus is on broadcast archives, our findings should be readily transferable to other scenarios where there is a need to store large volumes of digital data over long periods of time

The influence of national culture on the attitude towards mobile recommender systems

This is the post-print version of the final paper published in Technological Forecasting and Social Change. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2013 Elsevier B.V.This study aimed to identify factors that influence user attitudes towards mobile recommender systems and to examine how these factors interact with cultural values to affect attitudes towards this technology. Based on the theory of reasoned action, belief factors for mobile recommender systems are identified in three dimensions: functional, contextual, and social. Hypotheses explaining different impacts of cultural values on the factors affecting attitudes were also proposed. The research model was tested based on data collected in China, South Korea, and the United Kingdom. Findings indicate that functional and social factors have significant impacts on user attitudes towards mobile recommender systems. The relationships between belief factors and attitudes are moderated by two cultural values: collectivism and uncertainty avoidance. The theoretical and practical implications of applying theory of reasoned action and innovation diffusion theory to explain the adoption of new technologies in societies with different cultures are also discussed.National Research Foundation of Korea Grant funded by the Korean governmen

Affine maps of density matrices

For quantum systems described by finite matrices, linear and affine maps of matrices are shown to provide equivalent descriptions of evolution of density matrices for a subsystem caused by unitary Hamiltonian evolution in a larger system; an affine map can be replaced by a linear map, and a linear map can be replaced by an affine map. There may be significant advantage in using an affine map. The linear map is generally not completely positive, but the linear part of an equivalent affine map can be chosen to be completely positive and related in the simplest possible way to the unitary Hamiltonian evolution in the larger system.Comment: 4 pages, title changed, sentence added, reference update

A non-equilibrium ortho-to-para ratio of water in the Orion PDR

The ortho-to-para ratio (OPR) of H$_2$O is thought to be sensitive to the temperature of water formation. The OPR of H$_2$O is thus useful to study the formation mechanism of water. We investigate the OPR of water in the Orion PDR (Photon-dominated region), at the Orion Bar and Orion S positions, using data from {\it Herschel}/HIFI. We detect the ground-state lines of ortho- and para-H$_2$$^{18}$O in the Orion Bar and Orion S and we estimate the column densities using LTE and non-LTE methods. Based on our calculations, the ortho-to-para ratio (OPR) in the Orion Bar is 0.1 $-$ 0.5, which is unexpectedly low given the gas temperature of $\sim$ 85 K, and also lower than the values measured for other interstellar clouds and protoplanetary disks. Toward Orion S, our OPR estimate is below 2. This low OPR at 2 positions in the Orion PDR is inconsistent with gas phase formation and with thermal evaporation from dust grains, but it may be explained by photodesorption