795 research outputs found
Effect of risk perception on epidemic spreading in temporal networks
Many progresses in the understanding of epidemic spreading models have been
obtained thanks to numerous modeling efforts and analytical and numerical
studies, considering host populations with very different structures and
properties, including complex and temporal interaction networks. Moreover, a
number of recent studies have started to go beyond the assumption of an absence
of coupling between the spread of a disease and the structure of the contacts
on which it unfolds. Models including awareness of the spread have been
proposed, to mimic possible precautionary measures taken by individuals that
decrease their risk of infection, but have mostly considered static networks.
Here, we adapt such a framework to the more realistic case of temporal networks
of interactions between individuals. We study the resulting model by analytical
and numerical means on both simple models of temporal networks and empirical
time-resolved contact data. Analytical results show that the epidemic threshold
is not affected by the awareness but that the prevalence can be significantly
decreased. Numerical studies highlight however the presence of very strong
finite-size effects, in particular for the more realistic synthetic temporal
networks, resulting in a significant shift of the effective epidemic threshold
in the presence of risk awareness. For empirical contact networks, the
awareness mechanism leads as well to a shift in the effective threshold and to
a strong reduction of the epidemic prevalence
Aging and percolation dynamics in a Non-Poissonian temporal network model
We present an exhaustive mathematical analysis of the recently proposed
Non-Poissonian Ac- tivity Driven (NoPAD) model [Moinet et al. Phys. Rev. Lett.,
114 (2015)], a temporal network model incorporating the empirically observed
bursty nature of social interactions. We focus on the aging effects emerging
from the Non-Poissonian dynamics of link activation, and on their effects on
the topological properties of time-integrated networks, such as the degree
distribution. Analytic expressions for the degree distribution of integrated
networks as a function of time are derived, ex- ploring both limits of
vanishing and strong aging. We also address the percolation process occurring
on these temporal networks, by computing the threshold for the emergence of a
giant connected component, highlighting the aging dependence. Our analytic
predictions are checked by means of extensive numerical simulations of the
NoPAD model
Invoice from Charles Moinet to Ogden Goelet
https://digitalcommons.salve.edu/goelet-personal-expenses/1110/thumbnail.jp
Random walks in non-Poissoinan activity driven temporal networks
The interest in non-Markovian dynamics within the complex systems community has recently blossomed, due to a new wealth of time-resolved data pointing out the bursty dynamics of many natural and human interactions, manifested in an inter-event time between consecutive interactions showing a heavy-tailed distribution. In particular, empirical data has shown that the bursty dynamics of temporal networks can have deep consequences on the behavior of the dynamical processes running on top of them. Here, we study the case of random walks, as a paradigm of diffusive processes, unfolding on temporal networks generated by a non-Poissonian activity driven dynamics. We derive analytic expressions for the steady state occupation probability and first passage time distribution in the infinite network size and strong aging limits, showing that the random walk dynamics on non-Markovian networks are fundamentally different from what is observed in Markovian networks. We found a particularly surprising behavior in the limit of diverging average inter-event time, in which the random walker feels the network as homogeneous, even though the activation probability of nodes is heterogeneously distributed. Our results are supported by extensive numerical simulations. We anticipate that our findings may be of interest among the researchers studying non-Markovian dynamics on time-evolving complex topologies.Postprint (published version
Mage - Reactive articulatory feature control of HMM-based parametric speech synthesis
In this paper, we present the integration of articulatory control into MAGE, a framework for realtime and interactive (reactive) parametric speech synthesis using hidden Markov models (HMMs). MAGE is based on the speech synthesis engine from HTS and uses acoustic features (spectrum and f0) to model and synthesize speech. In this work, we replace the standard acoustic models with models combining acoustic and articulatory features, such as tongue, lips and jaw positions. We then use feature-space-switched articulatory-to-acoustic regression matrices to enable us to control the spectral acoustic features by manipulating the articulatory features. Combining this synthesis model with MAGE allows us to interactively and intuitively modify phones synthesized in real time, for example transforming one phone into another, by controlling the configuration of the articulators in a visual display. Index Terms: speech synthesis, reactive, articulators 1
Stylistic gait synthesis based on hidden Markov models
peer reviewedIn this work we present an expressive gait synthesis system based on hidden Markov models (HMMs), following and modifying a procedure originally developed for speaking style adaptation, in speech synthesis. A large database of neutral motion capture walk sequences was used to train an HMM of average walk. The model was then used for automatic adaptation to a particular style of walk using only a small amount of training data from the target style. The open source toolkit that we adapted for motion modeling also enabled us to take into account the dynamics of the data and to model accurately the duration of each HMM state. We also address the assessment issue and propose a procedure for qualitative user evaluation of the synthesized sequences. Our tests show that the style of these sequences can easily be recognized and look natural to the evaluators
Defining tools to address over-constrained geometric problems
International audienceThis paper proposes a new tool for decision support to address geometric over-constrained problems in Computer Aided Design (CAD). It concerns the declarative modeling of geometrical problems. The core of the coordinate free solver used to solve the Geometric Constraint Satisfaction Problem (GCSP) was developed previously by the authors. This research proposes a methodology based on Michelucci's witness method to determine whether the structure of the problem is over-constrained. In this case, the authors propose a tool for assisting the designer in solving the over-constrained problem by ensuring the consistency of the specifications. An application of the methodology and tool is presented in an academic example
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