53 research outputs found
Absorbing-state phase transitions in fixed-energy sandpiles
We study sandpile models as closed systems, with conserved energy density
playing the role of an external parameter. The critical energy density,
, marks a nonequilibrium phase transition between active and absorbing
states. Several fixed-energy sandpiles are studied in extensive simulations of
stationary and transient properties, as well as the dynamics of roughening in
an interface-height representation. Our primary goal is to identify the
universality classes of such models, in hopes of assessing the validity of two
recently proposed approaches to sandpiles: a phenomenological continuum
Langevin description with absorbing states, and a mapping to driven interface
dynamics in random media. Our results strongly suggest that there are at least
three distinct universality classes for sandpiles.Comment: 41 pages, 23 figure
Open data from the third observing run of LIGO, Virgo, KAGRA, and GEO
The global network of gravitational-wave observatories now includes five detectors, namely LIGO Hanford, LIGO Livingston, Virgo, KAGRA, and GEO 600. These detectors collected data during their third observing run, O3, composed of three phases: O3a starting in 2019 April and lasting six months, O3b starting in 2019 November and lasting five months, and O3GK starting in 2020 April and lasting two weeks. In this paper we describe these data and various other science products that can be freely accessed through the Gravitational Wave Open Science Center at https://gwosc.org. The main data set, consisting of the gravitational-wave strain time series that contains the astrophysical signals, is released together with supporting data useful for their analysis and documentation, tutorials, as well as analysis software packages
Geconditioneerd Simuleren van Ruimtelijke Stochastische Processen voor Reservoir Heterogeniteit
Electrical Engineering, Mathematics and Computer Scienc
Answering attitudinal questions : Modeling the response process underlying contrastive questions
We analyse reaction time distributions and responses for attitudinal survey questions, which were part of a self‐administered questionnaire about medical and ethical issues. Two contrastive versions of each question were asked, whether an issue should be forbidden or whether the government should allow it. Logically, the answers to these contrastive questions should oppose, but numerous investigations have shown that they result in the so‐called forbid/allow asymmetry: respondents tend to rather say ‘no’ to both questions. We present a mathematical model, based on point process theory, which formalises attitude representations in memory and different stages in the response process. The data of the allow questions are used for parameter estimation, while the forbid data are used to test the predictive power of different model versions. The result is a model that describes the cognitive processes underlying the asymmetry. It indicates that the forbid/allow asymmetry is caused by the use of an increased response threshold in forbid answers, and that the asymmetry size varies due to both respondent characteristics and the issue at hand. This model is capable of simultaneously predicting the asymmetry in the reaction time distributions and in the response scores for the answering categories
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