886,908 research outputs found
Combining causal model and focus group discussions experiences learned from a socio-anthropological research on the differing perceptions of caretakers and health professionals on children's health (Bolivia/Peru)
The paper discusses the utility of constructing causal models in focus groups. This was experienced as a complement to an in-depth ethnographic research on the differing perceptions of caretakers and health professionals on child's growth and development in Peru and Bolivia. The rational, advantages, difficulties and necessary adaptations of combining the two techniques are discussed on the basis of concrete examples. Authors conclude that the building of a causal model in a focus group session can be useful in comparing lay etiologies of diseases as perceived by different categories of caretakers and health professionals and in identifying specific health risks faced by children. Causal model building in a focus group can help renew discussions and participants'interest but its use is only justified when the study concerns the perception of the causality of a given phenomenon
Controlled Data Sharing for Collaborative Predictive Blacklisting
Although sharing data across organizations is often advocated as a promising
way to enhance cybersecurity, collaborative initiatives are rarely put into
practice owing to confidentiality, trust, and liability challenges. In this
paper, we investigate whether collaborative threat mitigation can be realized
via a controlled data sharing approach, whereby organizations make informed
decisions as to whether or not, and how much, to share. Using appropriate
cryptographic tools, entities can estimate the benefits of collaboration and
agree on what to share in a privacy-preserving way, without having to disclose
their datasets. We focus on collaborative predictive blacklisting, i.e.,
forecasting attack sources based on one's logs and those contributed by other
organizations. We study the impact of different sharing strategies by
experimenting on a real-world dataset of two billion suspicious IP addresses
collected from Dshield over two months. We find that controlled data sharing
yields up to 105% accuracy improvement on average, while also reducing the
false positive rate.Comment: A preliminary version of this paper appears in DIMVA 2015. This is
the full version. arXiv admin note: substantial text overlap with
arXiv:1403.212
On the origin of the Korteweg-de Vries equation
The Korteweg-de Vries equation has a central place in a model for waves on
shallow water and it is an example of the propagation of weakly dispersive and
weakly nonlinear waves. Its history spans a period of about sixty years,
starting with experiments of Scott Russell in 1834, followed by theoretical
investigations of, among others, Lord Rayleigh and Boussinesq in 1871 and,
finally, Korteweg and De Vries in 1895.
In this essay we compare the work of Boussinesq and Korteweg-de Vries,
stressing essential differences and some interesting connections. Although
there exist a number of articles, reviewing the origin and birth of the
Korteweg-de Vries equations, connections and differences, not generally known,
are reported.Comment: minor corrections; 25 pages, 3 figure
Search for QCD-instantons at HERA
Signals of QCD instanton induced processes are searched for in deep-inelastic
ep scattering at HERA in a kinematic region defined by the Bjorken scaling
variables x>0.001, 0.1156
degrees. Upper limits are derived from the expected instanton-induced final
state properties based on the QCDINS Monte Carlo model.Comment: 3 pages, 4 figures, World Scientific Doc. class (included); For the
H1 Collaboration; to be publ. in Proc. ICHEP 2000, Osak
Genuine Correlations in Hadronic Z Decays
Correlations among hadrons with the same electric charge produced in Z
decays are studied using the high statistics data collected from 1991 through
1995 with the OPAL detector at LEP. Normalized factorial cumulants up to fourth
order are used to measure genuine pa rticle correlations as a function of the
size of phase space domains in rapidity, azimuthal angle and transverse
momentum. tein correlations. Some of the recently proposed algorithms to
simulate Bose-Einstein effects, implemented in the Monte Carlo model \PYTHIA,
reproduce reasonably well the me asured second- and higher-order correlations
between particles with the same charge as well as those in all-charge particle
multiplets.Comment: 6 pages, 4 figures (in ps), talk given at XXXI International
Symposium on Multiparticle Dynamics, Sept 1-7, 2001, Datong China. See
http://202.114.35.18
Electric-field control of a hydrogenic donor's spin in a semiconductor
An AC electric field applied to a donor-bound electron in a semiconductor
modulates the orbital character of its wave function, which affects the
electron's spin dynamics via the spin-orbit interaction. Numerical calculations
of the spin dynamics of a hydrogenic donor (Si) embedded in GaAs, using a
real-space multi-band k.p formalism, show the high symmetry of the hydrogenic
donor state results in strongly nonlinear dependences of the electronic g
tensor on applied fields. A nontrivial consequence is that the most rapid Rabi
oscillations occur for electric fields modulated at a subharmonic of the Larmor
frequency
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