4,820 research outputs found
A Methodology to Engineer and Validate Dynamic Multi-level Multi-agent Based Simulations
This article proposes a methodology to model and simulate complex systems,
based on IRM4MLS, a generic agent-based meta-model able to deal with
multi-level systems. This methodology permits the engineering of dynamic
multi-level agent-based models, to represent complex systems over several
scales and domains of interest. Its goal is to simulate a phenomenon using
dynamically the lightest representation to save computer resources without loss
of information. This methodology is based on two mechanisms: (1) the activation
or deactivation of agents representing different domain parts of the same
phenomenon and (2) the aggregation or disaggregation of agents representing the
same phenomenon at different scales.Comment: Presented at 3th International Workshop on Multi-Agent Based
Simulation, Valencia, Spain, 5th June 201
Tracing sediment transport and bed regime in Nha Trang Bay
Three spatial structure groups of radionuclides in U and Th series, 210Pb-excess and 137Cs, and 40K were found based on analyzing temporal and spatial datum of their content by factor analysis with oblique rotation in Nhatrang bay.
U and Th spatial structure with their contours decreased toward the offshore, ran longshore and divided seawater of bay into two parts with strong gradient on both sides. Inside part located from center of Nhatrang bay toward the seashore with three main deposit centers of their contents higher than 23 Bq/kg.dry for 238U and 40 Bq/kg.dry for 232Th, indicated unstability of shoreline. Almost sediments coming from river extended toward the offshore, were stopped and transported toward southeastern. The outside part was less than above
mentioned content. The boundary line between two parts superposed with the constantly limit line of turbid plume in the rainy season. Direct influence of the continental runoff was limited by the 9 Bq/kg.dry contour of 238U, 19 Bq/kg.dry contour of 232Th. Longshore current was a predominant process whereas lateral transport as sifting and winnowing process of finer grains in sediments of Nhatrang bay. Areas that had very low content of 137Cs and 210
Pb-excess adjoining shoreline showed areas being eroded. Accumulation of 137Cs and 210 Pbexcess nearby river mouth characterized for fine compositions of sediments controlled by seasonal plumes and sites further toward the south indicated finer materials transported from river and accumulated in lack of hydrodynamic process. Near shore accumulation of 40K revealed the sediments there originated from bed erosion
Fermions and noncommutative emergent gravity II: Curved branes in extra dimensions
We study fermions coupled to Yang-Mills matrix models from the point of view
of emergent gravity. The matrix model Dirac operator provides an appropriate
coupling for fermions to the effective gravitational metric for general branes
with nontrivial embedding, albeit with a non-standard spin connection. This
generalizes previous results for 4-dimensional matrix models. Integrating out
the fermions in a nontrivial geometrical background induces indeed the
Einstein-Hilbert action of the effective metric, as well as additional terms
which couple the Poisson tensor to the Riemann tensor, and a dilaton-like term.Comment: 34 pages; minor change
Integrated spatial multiplexing of heralded single photon sources
The non-deterministic nature of photon sources is a key limitation for single
photon quantum processors. Spatial multiplexing overcomes this by enhancing the
heralded single photon yield without enhancing the output noise. Here the
intrinsic statistical limit of an individual source is surpassed by spatially
multiplexing two monolithic silicon correlated photon pair sources,
demonstrating a 62.4% increase in the heralded single photon output without an
increase in unwanted multi-pair generation. We further demonstrate the
scalability of this scheme by multiplexing photons generated in two waveguides
pumped via an integrated coupler with a 63.1% increase in the heralded photon
rate. This demonstration paves the way for a scalable architecture for
multiplexing many photon sources in a compact integrated platform and achieving
efficient two photon interference, required at the core of optical quantum
computing and quantum communication protocols.Comment: 10 pages, 3 figures, comments welcom
From atomistic structure to thermodynamics and mechanical properties of epoxy/clay nanocomposites: Investigation by molecular dynamics simulations
International audienc
A Prototype Decision Support Tool for Ballast Water Risk Management using a Combination of Hydrodynamic Models and Agent-Based Modelling
We report the development of a prototype Decision Support Tool (DST) for modelling the risks of spreading of non-indegenous invasive species via ballast water. The DST constitutes of two types of models: A 3D hydrodynamical model calculates the currents in the North Sea and Danish Straits, and an agent-based model estimates the dispersal of selected model organisms with the prevailing currents calculated by the 3D hydrodynamical model. The analysis is concluded by a post processing activity, where scenarios of dispersal are combined into an interim estimate of connectivity within the study area. The latter can be used as a tool for assessment of potential risk associated with intentional or unintentional discharges of ballast water. We discuss how this prototype DST can be used for ballast water risk management and outline other functions and uses, e.g. in regard to ecosystem-based management and the implementation of the EU Marine Strategy Framework Directive.https://commons.wmu.se/nsbwo/1001/thumbnail.jp
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