4,628 research outputs found
Towards agent-based crowd simulation in airports using games technology
We adapt popular video games technology for an agent-based crowd simulation in an airport terminal. To achieve this, we investigate the unique traits of airports and implement a virtual crowd by exploiting a scalable layered intelligence technique in combination with physics middleware and a socialforces approach. Our experiments show that the framework runs at interactive frame-rate and evaluate the scalability with increasing number of agents demonstrating
navigation behaviour
A Simulation Model to Evaluate Supplementation of Tropical Forage Diets for Dairy Cows
A dynamic model of digestion kinetics has been built to evaluate dairy cattle diets based on tropical feeds and to estimate the potential of tropical forages for milk production associated with available supplements. Results of simulation were very consistent showing that grazed elephant grass alone can supply nutrients for cow maintenance and yield of 7.10 kg milk/day. Nevertheless, to produce 25 kg/day on grazed elephant grass, a dairy cow would need to be supplemented with 5.85 kg/day of a mixture of cottonseed meal (50%) plus ground maize (50%), while on maize silage it would be necessary 4.15 kg of the same supplementation. On the other hand, for the same amount of milk, a cow fed a sugarcane/urea-based diet would need 5.87 kg of the above mixture. As far as feeding cost is concerned, to reach the potential production of 25 kg of milk/day, a cow would expend US 1.40 on sugarcane- and maize silage-based diets. The present model showed to be an useful tool for assessing, preexperimentally, the potential response to supplementation of dairy cows fed tropical forages
Statistics in the Landscape of Intersecting Brane Models
An approach towards a statistical survey of four dimensional supersymmetric
vacua in the string theory landscape is described and illustrated with three
examples of ensembles of intersecting D-brane models. The question whether it
is conceivable to make predictions based on statistical distributions is
discussed. Especially interesting in this context are possible correlations
between low energy observables. As an example we look at correlations between
properties of the gauge sector of intersecting D-brane models and Gepner model
constructions.Comment: Submitted for the SUSY07 proceedings, 4 pages, 2 figure
Proposal to Search for Heavy Neutral Leptons at the SPS
A new fixed-target experiment at the CERN SPS accelerator is proposed that
will use decays of charm mesons to search for Heavy Neutral Leptons (HNLs),
which are right-handed partners of the Standard Model neutrinos. The existence
of such particles is strongly motivated by theory, as they can simultaneously
explain the baryon asymmetry of the Universe, account for the pattern of
neutrino masses and oscillations and provide a Dark Matter candidate.
Cosmological constraints on the properties of HNLs now indicate that the
majority of the interesting parameter space for such particles was beyond the
reach of the previous searches at the PS191, BEBC, CHARM, CCFR and NuTeV
experiments. For HNLs with mass below 2 GeV, the proposed experiment will
improve on the sensitivity of previous searches by four orders of magnitude and
will cover a major fraction of the parameter space favoured by theoretical
models.
The experiment requires a 400 GeV proton beam from the SPS with a total of
2x10^20 protons on target, achievable within five years of data taking. The
proposed detector will reconstruct exclusive HNL decays and measure the HNL
mass. The apparatus is based on existing technologies and consists of a target,
a hadron absorber, a muon shield, a decay volume and two magnetic
spectrometers, each of which has a 0.5 Tm magnet, a calorimeter and a muon
detector. The detector has a total length of about 100 m with a 5 m diameter.
The complete experimental set-up could be accommodated in CERN's North Area.
The discovery of a HNL would have a great impact on our understanding of
nature and open a new area for future research
Compactness in Banach space theory - selected problems
We list a number of problems in several topics related to compactness in
nonseparable Banach spaces. Namely, about the Hilbertian ball in its weak
topology, spaces of continuous functions on Eberlein compacta, WCG Banach
spaces, Valdivia compacta and Radon-Nikod\'{y}m compacta
Developing methodology for efficient eelgrass habitat mapping across lidar systems
Super Storm Sandy, the second costliest hurricane in U.S. history, made landfall on the east coast of the U.S. in October 2012. In an attempt to assess the impacts of the storm on coastal ecosystems, several U.S. mapping agencies such as the National Oceanic and Atmospheric Administration (NOAA), the U.S. Geological Survey (USGS), and the U.S. Army Corps of Engineers (USACE) commenced data collection efforts using a variety of remotely-sensed data types including aerial imagery and topobathymetric lidar. The objective of this study was to investigate the applicability of object-based image analysis techniques for benthic habitat mapping. Bathymetry and reflectance data collected by a Riegl VQ-820-G system and the AHAB Chiroptera system along with aerial imagery (Applanix DSS) were compared using an objectbased image analysis (OBIA) technique to classify dense eelgrass beds, mixed sand and macroalgae, and sand habitats. In order to determine the efficacy of this method for benthic habitat classification it was also compared to a manual method of classification from aerial imagery. The resulting habitat maps were compared between systems to determine the feasibility of using one OBIA classification rule set across lidar systems and aerial imagery. Our preliminary results using the Riegl system suggest our methodology correctly classified 85% of benthic habitats. Preliminary results using the Chiroptera also suggests similar accuracy of classification. This methodology will allow streamlined creation of habitat maps for coastal managers and researchers using large sets of data collected by multiple sensors. Testing of this OBIA methodology is ongoing as new data from various sensors becomes available
Self-stabilizing Leader Election in Population Protocols over Arbitrary Communication Graphs
This paper considers the fundamental problem of \emph{self-stabilizing leader election} () in the model of \emph{population protocols}. In this model, an unknown number of asynchronous, anonymous and finite state mobile agents interact in pairs over a given communication graph. has been shown to be impossible in the original model. This impossibility can been circumvented by a modular technique augmenting the system with an \emph{oracle} - an external module abstracting the added assumption about the system. Fischer and Jiang have proposed solutions to , for complete communication graphs and rings, using an oracle , called the \emph{eventual leader detector}. In this work, we present a solution for arbitrary graphs, using a \emph{composition} of two copies of . We also prove that the difficulty comes from the requirement of self-stabilization, by giving a solution without oracle for arbitrary graphs, when an uniform initialization is allowed. Finally, we prove that there is no self-stabilizing \emph{implementation} of using , in a sense we define precisely
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