5,109 research outputs found

    Bayesian inference for partially observed stochastic differential equations driven by fractional Brownian motion

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    We consider continuous-time diffusion models driven by fractional Brownian motion. Observations are assumed to possess a nontrivial likelihood given the latent path. Due to the non-Markovian and high-dimensional nature of the latent path, estimating posterior expectations is computationally challenging. We present a reparameterization framework based on the Davies and Harte method for sampling stationary Gaussian processes and use it to construct a Markov chain Monte Carlo algorithm that allows computationally efficient Bayesian inference. The algorithm is based on a version of hybrid Monte Carlo simulation that delivers increased efficiency when used on the high-dimensional latent variables arising in this context. We specify the methodology on a stochastic volatility model, allowing for memory in the volatility increments through a fractional specification. The method is demonstrated on simulated data and on the S&P 500/VIX time series. In the latter case, the posterior distribution favours values of the Hurst parameter smaller than 1/2 , pointing towards medium-range dependence

    The predictors of economic sophistication: media, interpersonal communication and negative economic experiences

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    In analogy to political sophistication, it is imperative that citizens have a certain level of economic sophistication, especially in times of heated debates about the economy. This study examines the impact of different influences (media, interpersonal communication and personal experiences) on learning effects about the economy. We conducted a national two-wave panel survey and a media content analysis in Denmark. Media effects were examined through integrating the results of the content analysis (in which articles were coded for the presence of the economic consequences frame) with the panel survey. Results showed that exposure to economic consequences frames in the media and interpersonal communication about the economy had a significant positive influence on learning about the economy. Having negative experiences with the economy exerts significant negative influence on learning. Interestingly, extensive interpersonal communication and negative experiences with the economy dampen media effects on learning about the economy. The study contributes to the literature on the cognitive effects of media and of interpersonal communication, as well as in media dependency theory

    A stochastic derivation of the geodesic rule

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    We argue that the geodesic rule, for global defects, is a consequence of the randomness of the values of the Goldstone field Ď•\phi in each causally connected volume. As these volumes collide and coalescence, Ď•\phi evolves by performing a random walk on the vacuum manifold M\mathcal{M}. We derive a Fokker-Planck equation that describes the continuum limit of this process. Its fundamental solution is the heat kernel on M\mathcal{M}, whose leading asymptotic behavior establishes the geodesic rule.Comment: 12 pages, No figures. To be published in Int. Jour. Mod. Phys.

    Prototyping and qualification of 2S modules for the CMS Outer Tracker upgrade at the HL-LHC

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    In preparation for the High Luminosity LHC, the entire tracker detector of the CMS experiment will be exchanged as part of the Phase-2 Upgrade. The new Outer Tracker will comprise approximately 13,000 silicon sensor modules, of which 7608 are "2S modules" consisting of two parallel mounted silicon strip sensors, and 5592 are "PS modules" consisting of one pixel and one strip sensor in a single module. These modules provide tracking information to the Level 1 trigger by correlating the hit information of both sensor layers, allowing discrimination of particle tracks by their transverse momentum. To guarantee successful operation during data-taking, the production of the outer tracker modules has to fulfill strict requirements. This note will discuss the assembly procedures as well as some key results of the electronic, thermal and vibration tests performed at CERN for qualifying the 2S module design and for preparing the module assembly procedures
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