367 research outputs found

    Random vectors on the spin configuration of a Curie-Weiss model on Erdos-Renyi random graphs

    Full text link
    This article is concerned with the asymptotic behaviour of random vectors in a diluted ferromagnetic model. We consider a model introduced by Bovier & Gayrard (1993) with ferromagnetic interactions on a directed Erd\H{o}s-R\'enyi random graph. Here, directed connections between graph nodes are uniformly drawn at random with a probability p that depends on the number of nodes N and is allowed to go to zero in the limit. If Np⟶∞Np\longrightarrow\infty in this model, Bovier & Gayrard (1993) proved a law of large numbers almost surely, and Kabluchko et al. (2020) proved central limit theorems in probability. Here, we generalise these results for ÎČ<1\beta<1 in the regime Np⟶∞Np\longrightarrow\infty. We show that all those random vectors on the spin configuration that have a limiting distribution under the Curie-Weiss model converge weakly towards the same distribution under the diluted model, in probability on graph realisations. This generalises various results from the Curie-Weiss model to the diluted model. As a special case, we derive a law of large numbers and central limit theorem for two disjoint groups of spins

    Better safe than sorry: Risky function exploitation through safe optimization

    Get PDF
    Exploration-exploitation of functions, that is learning and optimizing a mapping between inputs and expected outputs, is ubiquitous to many real world situations. These situations sometimes require us to avoid certain outcomes at all cost, for example because they are poisonous, harmful, or otherwise dangerous. We test participants' behavior in scenarios in which they have to find the optimum of a function while at the same time avoid outputs below a certain threshold. In two experiments, we find that Safe-Optimization, a Gaussian Process-based exploration-exploitation algorithm, describes participants' behavior well and that participants seem to care firstly whether a point is safe and then try to pick the optimal point from all such safe points. This means that their trade-off between exploration and exploitation can be seen as an intelligent, approximate, and homeostasis-driven strategy.Comment: 6 pages, submitted to Cognitive Science Conferenc

    Sustained Magnetic Responses in Temporal Cortex Reflect Instantaneous Significance of Approaching and Receding Sounds

    Get PDF
    Rising sound intensity often signals an approaching sound source and can serve as a powerful warning cue, eliciting phasic attention, perception biases and emotional responses. How the evaluation of approaching sounds unfolds over time remains elusive. Here, we capitalised on the temporal resolution of magnetoencephalograpy (MEG) to investigate in humans a dynamic encoding of perceiving approaching and receding sounds. We compared magnetic responses to intensity envelopes of complex sounds to those of white noise sounds, in which intensity change is not perceived as approaching. Sustained magnetic fields over temporal sensors tracked intensity change in complex sounds in an approximately linear fashion, an effect not seen for intensity change in white noise sounds, or for overall intensity. Hence, these fields are likely to track approach/recession, but not the apparent (instantaneous) distance of the sound source, or its intensity as such. As a likely source of this activity, the bilateral inferior temporal gyrus and right temporo-parietal junction emerged. Our results indicate that discrete temporal cortical areas parametrically encode behavioural significance in moving sound sources where the signal unfolded in a manner reminiscent of evidence accumulation. This may help an understanding of how acoustic percepts are evaluated as behaviourally relevant, where our results highlight a crucial role of cortical areas

    Energieversorgungssicherheit jenseits der Geopolitik : Wie reagiert die EU auf Risiken insbesondere fĂŒr die Öl- und Erdgasversorgung?

    Get PDF
    Die Politikwissenschaft betrachtet die Energieversorgungssicherheit in der Regel durch die Brille der Außenpolitik. Im Fokus stehen dann etwa die OPEC, Russland, die Ukraine, der Nahe Osten, Nordafrika, die TĂŒrkei, der Kaukasus, die Schiefergasrevolution in den USA und zahlreiche weitere Themenkomplexe. Dieser Blickwinkel besitzt zweifelsohne seine Berechtigung und wird auch in der vorliegenden Arbeit nicht vernachlĂ€ssigt. Doch reicht dieser Blick nicht aus, um der KomplexitĂ€t der Energieversorgungssicherheit heute Gerecht zu werden. EnergiemĂ€rkte werden immer komplexer, ihre Regulierung ebenso. Ferner mehren sich Eingriffe der Politik, nicht zuletzt aus GrĂŒnden des Umweltschutzes. Zur KomplexitĂ€t tragen zudem die vielen Ebenen bei, die es zu berĂŒcksichtigen gilt: Die lokale, die regionale, die nationale, die europĂ€ische und nicht zuletzt die globale. Die vorliegende Arbeit stellt das PhĂ€nomen der Energieversorgungssicherheit in dieser KomplexitĂ€t dar. Dabei liegen die Schwerpunkte auf der Erdöl-, Erdgas- sowie ElektrizitĂ€tsversorgung und auf der EuropĂ€ischen Union, wobei auch die Wechselspiele mit nationalen Energiepolitiken, primĂ€r am Beispiel Deutschlands, nicht vernachlĂ€ssigt werden. Dabei wird deutlich, dass die Sicherheit der Energieversorgung oftmals durch fehlende KohĂ€renz im Innern, sei es auf Ebene der EuropĂ€ischen Union oder auf nationaler Ebene, beeintrĂ€chtigt wird. Einer eingehenden Untersuchung werden dabei folgende Gefahrenblöcke unterzogen: Klassische geopolitische Risiken, territoriale Streitigkeiten und Embargos, Piraterie und Terrorismus, Risiken durch Naturgewalten, die Energiemarktregulierung sowie weitere regulatorische Eingriffe bis hin zu Umweltschutzvorgaben

    A linear model for event-related respiration responses

    Get PDF
    AbstractBackgroundCognitive processes influence respiratory physiology. This may allow inferring cognitive states from measured respiration. Here, we take a first step towards this goal and investigate whether event-related respiratory responses can be identified, and whether they are accessible to a model-based approach.New methodWe regard respiratory responses as the output of a linear time invariant system that receives brief inputs after psychological events. We derive average responses to visual targets, aversive stimulation, and viewing of arousing pictures, in interpolated respiration period (RP), respiration amplitude (RA), and respiratory flow rate (RFR). We then base a Psychophysiological Model (PsPM) on these averaged event-related responses. The PsPM is inverted to yield estimates of cognitive input into the respiratory system. This method is validated in an independent data set.ResultsAll three measures show event-related responses, which are captured as non-zero response amplitudes in the PsPM. Amplitude estimates for RA and RFR distinguish between picture viewing and the other tasks. This pattern is replicated in the validation experiment.Comparison with existing methodsExisting respiratory measures are based on relatively short time-intervals after an event while the new method is based on the entire duration of respiratory responses.ConclusionOur findings suggest that interpolated respiratory measures show replicable event-related response patterns. PsPM inversion is a suitable approach to analysing these patterns, with a potential to infer cognitive processes from respiration

    Analytic measures for quantification of arousal from spontaneous skin conductance fluctuations

    Get PDF
    AbstractAutonomic arousal is often indexed by spontaneous fluctuations in skin conductance. Here, we derive a simple measure of sympathetic arousal, using a convolution model of how sudomotor bursting causes fluctuations in skin conductivity. Under this model, the time-integral of measured conductance is proportional to the frequency and amplitude of sudomotor bursts. We demonstrate the validity of this measure in relation to finite impulse response models, and show that it is a better predictor of autonomic arousal, relative to conventional measures

    FlexibleSUSY: Precise automated calculations in any BSM theory

    Full text link
    FlexibleSUSY is a software package for various calculations in any model of physics beyond the standard model (not just any supersymmetric model). FlexibleSUSY can solve boundary value problems and uses this to find DR‟/MS‟\overline{DR}/\overline{MS} parameters and calculate the Higgs and BSM particle masses, as well as other observables. FlexibleSUSY is designed to be adaptable, fast, precise and reliable. We describe FlexibleSUSY with particular emphasis on recent developments and the state of the art Higgs mass calculations it can perform. We also show some applications to illustrate how it can be used to obtain interesting physics results with the highest precision possible and with remarkable speed.Comment: 4 pages plus title page, 1 figure. Contribution to proceedings of ICHEP 2018, the 39th International Conference on High Energy Physic
    • 

    corecore