351 research outputs found
Fast Kernel Approximations for Latent Force Models and Convolved Multiple-Output Gaussian processes
A latent force model is a Gaussian process with a covariance function
inspired by a differential operator. Such covariance function is obtained by
performing convolution integrals between Green's functions associated to the
differential operators, and covariance functions associated to latent
functions. In the classical formulation of latent force models, the covariance
functions are obtained analytically by solving a double integral, leading to
expressions that involve numerical solutions of different types of error
functions. In consequence, the covariance matrix calculation is considerably
expensive, because it requires the evaluation of one or more of these error
functions. In this paper, we use random Fourier features to approximate the
solution of these double integrals obtaining simpler analytical expressions for
such covariance functions. We show experimental results using ordinary
differential operators and provide an extension to build general kernel
functions for convolved multiple output Gaussian processes.Comment: 10 pages, 4 figures, accepted by UAI 201
Oral health and welfare state regimes: a cross-national analysis of European countries.
Very little is known about the potential relationship between welfare state regimes and oral health. This study assessed the oral health of adults in a range of European countries clustered by welfare regimes according to Ferrera's typology and the complementary Eastern type. We analysed data from Eurobarometer wave 72.3, a cross-sectional survey of 31 European countries carried out in 2009. We evaluated three self-reported oral health outcomes: edentulousness, no functional dentition (<20 natural teeth), and oral impacts on daily living. Age-standardized prevalence rates were estimated for each country and for each welfare state regime. The Scandinavian regime showed lower prevalence rates for all outcomes. For edentulousness and no functional dentition, there were higher prevalence rates in the Eastern regime but no significant differences between Anglo-Saxon, Bismarckian, and Southern regimes. The Southern regime presented a higher prevalence of oral impacts on daily living. Results by country indicated that Sweden had the lowest prevalences for edentulousness and no functional dentition, and Denmark had the lowest prevalence for oral impacts. The results suggest that Scandinavian welfare states, with more redistributive and universal welfare policies, had better population oral health. Future research should provide further insights about the potential mechanisms through which welfare-state regimes would influence oral health
IncorporaciĂłn de 2 modernos Dispositivos Ăpticos en el Algoritmo para el manejo de una VĂa AĂ©rea DifĂcil de la Sociedad Francesa de AnestesiologĂa
El seguimiento de Algoritmos puede resolver muchos problemas en el manejo de la VĂa AĂ©rea DifĂcil (VAD). La Sociedad Francesa de AnestesiologĂa ha creado su propio Algoritmo, introduciendo 2 modernos Dispositivos Ăpticos (con sistemas de video), el Laringoscopio Airtraq (con monitor externo sin cables) y la Mascarilla LarĂngea C-Trach
The Wolf of SUTD (TWOS): A dataset of malicious insider threat behavior based on a gamified competition
In this paper we present open research questions and options for data analysis of our previously designed dataset called TWOS: The Wolf of SUTD. In specified research questions, we illustrate the potential use of the TWOS dataset in multiple areas of cyber security, which does not limit only to malicious insider threat detection but are also related to authorship verification and identification, continuous authentication, and sentiment analysis. For the purpose of investigating the research questions, we present several state-of-the-art features applicable to collected data sources, and thus we provide researchers with a guidance how to start with data analysis. The TWOS dataset was collected during a gamified competition that was devised in order to obtain realistic instances of malicious insider threat. The competition simulated user interactions in/among competing companies, where two types of behaviors (normal and malicious) were incentivized. For the case of malicious behavior,we designed two types of malicious periods that was intended to capture the behavior of two types of insiders â masqueraders and traitors. The game involved the participation of 6 teams consisting of 4 students who competed with each other for a period of 5 days. Their activities were monitored by several data collection agents and producing data for mouse, keyboard, process and file-system monitor, network traffic, emails, and login/logout data sources. In total, we obtained 320 hours of active participation that included 18 hours of masquerader data and at least two instances of traitor data. In addition to expected malicious behaviors, students explored various defensive and offensive strategies such as denial of service attacks and obfuscation techniques, in an effort to get ahead in the competition. The TWOS dataset was made publicly accessible for further research purposes. In this paper we present the TWOS dataset that contains realistic instances of insider threats based on a gamified competition. The competition simulated user interactions in/among competing companies, where two types of behaviors (normal and malicious) were incentivized. For the case of malicious behavior, we designed sessions for two types of insider threats (masqueraders and traitors). The game involved the participation of 6 teams consisting of 4 students who competed with each other for a period of 5 days, while their activities were monitored considering several heterogeneous sources (mouse, keyboard, process and file-system monitor, network traffic, emails and login/logout). In total, we obtained 320 hours of active participation that included 18 hours of masquerader data and at least two instances of traitor data. In addition to expected malicious behaviors, students explored various defensive and offensive strategies such as denial of service attacks and obfuscation techniques, in an effort to get ahead in the competition. Furthermore, we illustrate the potential use of the TWOS dataset in multiple areas of cyber security, which does not limit to malicious insider threat detection, but also areas such as authorship verification and identification, continuous authentication, and sentiment analysis. We also present several state-of-the-art features that can be extracted from different data sources in order to guide researchers in the analysis of the dataset. The TWOS dataset is publicly accessible for further research purposes. © 2018, Innovative Information Science and Technology Research Group. All rights reserved
Topological mass generation and forms
In this work we revisit the topological mass generation of 2-forms and
establish a connection to the unique derivative coupling arising in the quartic
Lagrangian of the systematic construction of massive form interactions,
relating in this way BF theories to Galileon-like theories of 2-forms. In terms
of a massless form and a massless form , the topological term
manifests itself as the interaction , where is the
field strength of the form. Such an interaction leads to a mechanism of
generation of mass, usually referred to as "topological generation of mass" in
which the single degree of freedom propagated by the form is absorbed by
the form, generating a massive mode for the form. Using the
systematical construction in terms of the Levi-Civita tensor, it was shown
that, apart from the quadratic and quartic Lagrangians, Galileon-like
derivative self-interactions for the massive 2-form do not exist. A unique
quartic Lagrangian
arises in this construction in a way that it corresponds to a total derivative
on its own but ceases to be so once an overall general function is introduced.
We show that it exactly corresponds to the same interaction of topological mass
generation. Based on the decoupling limit analysis of the interactions, we
bring out supporting arguments for the uniqueness of such a topological mass
term and absence of the Galileon-like interactions. Finally, we discuss some
preliminary applications in cosmology.Comment: 14 pages, 3 figures, journal versio
Elevated atmospheric CO2 modifies responses to water-stress and flowering of Mediterranean desert truffle mycorrhizal shrubs
Predicted increases in atmospheric concentration of carbon dioxide (CO2) coupled with increased temperatures and drought are expected to strongly influence the development of most of the plant species in the world, especially in areas with high risk of desertification like the Mediterranean basin. Helianthemum almeriense is an ecologically important Mediterranean shrub with an added interest because it serves as the host for the Terfezia claveryi mycorrhizal fungus, which is a desert truffle with increasingly commercial interest. Although both plant and fungi are known to be well adapted to dry conditions, it is still uncertain how the increase in atmospheric CO2 will influence them. In this article we have addressed the physiological responses of H. almeriense Ă T. claveryi mycorrhizal plants to increases in atmospheric CO2 coupled with drought and high vapor pressure deficit. This work reports one of the few estimations of mesophyll conductance in a drought deciduous Mediterranean shrub and evaluates its role in photosynthesis limitation. High atmospheric CO2 concentrations help desert truffle mycorrhizal plants to cope with the adverse effects of progressive drought during Mediterranean springs by improving carbon net assimilation, intrinsic water use efficiency and dispersal of the species through increased flowering events
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