328 research outputs found
Confidentiality-Preserving Publish/Subscribe: A Survey
Publish/subscribe (pub/sub) is an attractive communication paradigm for
large-scale distributed applications running across multiple administrative
domains. Pub/sub allows event-based information dissemination based on
constraints on the nature of the data rather than on pre-established
communication channels. It is a natural fit for deployment in untrusted
environments such as public clouds linking applications across multiple sites.
However, pub/sub in untrusted environments lead to major confidentiality
concerns stemming from the content-centric nature of the communications. This
survey classifies and analyzes different approaches to confidentiality
preservation for pub/sub, from applications of trust and access control models
to novel encryption techniques. It provides an overview of the current
challenges posed by confidentiality concerns and points to future research
directions in this promising field
Random effects compound Poisson model to represent data with extra zeros
This paper describes a compound Poisson-based random effects structure for
modeling zero-inflated data. Data with large proportion of zeros are found in
many fields of applied statistics, for example in ecology when trying to model
and predict species counts (discrete data) or abundance distributions
(continuous data). Standard methods for modeling such data include mixture and
two-part conditional models. Conversely to these methods, the stochastic models
proposed here behave coherently with regards to a change of scale, since they
mimic the harvesting of a marked Poisson process in the modeling steps. Random
effects are used to account for inhomogeneity. In this paper, model design and
inference both rely on conditional thinking to understand the links between
various layers of quantities : parameters, latent variables including random
effects and zero-inflated observations. The potential of these parsimonious
hierarchical models for zero-inflated data is exemplified using two marine
macroinvertebrate abundance datasets from a large scale scientific bottom-trawl
survey. The EM algorithm with a Monte Carlo step based on importance sampling
is checked for this model structure on a simulated dataset : it proves to work
well for parameter estimation but parameter values matter when re-assessing the
actual coverage level of the confidence regions far from the asymptotic
conditions.Comment: 4
Trust and Privacy in Development of Publish/Subscribe Systems
Publish/subscribe (pub/sub) is a widely deployed paradigm for information dissemination in a variety of distributed applications such as financial platforms, e-health frameworks and the Internet-of-Things. In essence, the pub/sub model considers one or more publishers generating feeds of information and a set of subscribers, the clients of the system. A pub/sub service is in charge of delivering the published information to interested clients. With the advent of cloud computing, we observe a growing tendency to externalize applications using pub/sub services to public clouds. This trend, despite its advantages, opens up multiple important data privacy and trust issues. Although multiple solutions for data protection have been proposed by the academic community, there is no unified view or framework describing how to deploy secure pub/sub systems on public clouds. To remediate this, we advocate towards a trust model which we believe can serve as basis for such deployments
Les forêts anciennes en Wallonie. 2ème partie : Cartographie
Un premier article a démontré que l’identification des forêts anciennes est une étape
préalable pour pouvoir leur appliquer un mode de gestion spécifique et protéger le patrimoine
qu’elles représentent. Cette deuxième partie énumère les sources historiques disponibles
en Wallonie, donne un aperçu de l’état d’avancement du travail de numérisation de ces documents mené par le Service Public de Wallonie et en tire quelques informations très
surprenantes sur l’évolution spatiale et temporelle des massifs forestiers de Wallonie depuis
deux siècles et demi
Specific Entrainment of Mitral Cells during Gamma Oscillation in the Rat Olfactory Bulb
Local field potential (LFP) oscillations are often accompanied by synchronization of activity within a widespread cerebral area. Thus, the LFP and neuronal coherence appear to be the result of a common mechanism that underlies neuronal assembly formation. We used the olfactory bulb as a model to investigate: (1) the extent to which unitary dynamics and LFP oscillations can be correlated and (2) the precision with which a model of the hypothesized underlying mechanisms can accurately explain the experimental data. For this purpose, we analyzed simultaneous recordings of mitral cell (MC) activity and LFPs in anesthetized and freely breathing rats in response to odorant stimulation. Spike trains were found to be phase-locked to the gamma oscillation at specific firing rates and to form odor-specific temporal patterns. The use of a conductance-based MC model driven by an approximately balanced excitatory-inhibitory input conductance and a relatively small inhibitory conductance that oscillated at the gamma frequency allowed us to provide one explanation of the experimental data via a mode-locking mechanism. This work sheds light on the way network and intrinsic MC properties participate in the locking of MCs to the gamma oscillation in a realistic physiological context and may result in a particular time-locked assembly. Finally, we discuss how a self-synchronization process with such entrainment properties can explain, under experimental conditions: (1) why the gamma bursts emerge transiently with a maximal amplitude position relative to the stimulus time course; (2) why the oscillations are prominent at a specific gamma frequency; and (3) why the oscillation amplitude depends on specific stimulus properties. We also discuss information processing and functional consequences derived from this mechanism
Etude de lois de navigation pour la recherche de sources de gaz
Colloque avec actes et comité de lecture. nationale.National audienceOn dérive, dans une situation homogène et stationnaire, une famille de lois de navigation L(n) (0 < n < 1) pour un robot à la recherche d'une source de gaz. Ces lois lui permettent de converger vers la direction de la source et d'y rester de manière stable. Dans une situation inhomogène et en présence de bruit, ce dernier étant autant dû à la turbulence qu'au système permettant d'estimer la concentration en fonction des données des capteurs, la loi L(1/2) se révèle la plus efficace. Les performances restent étonnamment élevées même pour un bruit fort
Stereo-olfaction with a sniffing neuromorphic robot using spiking neurons
Colloque avec actes et comité de lecture. internationale.International audienceThis paper presents a neuromorphic robot using stereo-olfaction and a sniffing system based on nonselective chemosensors that mimic the animal behavior of tracking a specific odor. In order to be able to go toward an odor source, two tasks must be performed : 1) estimation of the gas-concentration gradient and 2) gas recognition independent of the intensity. It is shown how these two tasks can be implemented with artificial spiking neurons in a biologically inspired approach
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