6,109 research outputs found
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A genetic algorithm for the design of a fuzzy controller for active queue management
Active queue management (AQM) policies are those
policies of router queue management that allow for the detection of network congestion, the notification of such occurrences to the
hosts on the network borders, and the adoption of a suitable control
policy. This paper proposes the adoption of a fuzzy proportional
integral (FPI) controller as an active queue manager for Internet
routers. The analytical design of the proposed FPI controller is
carried out in analogy with a proportional integral (PI) controller,
which recently has been proposed for AQM. A genetic algorithm is
proposed for tuning of the FPI controller parameters with respect
to optimal disturbance rejection. In the paper the FPI controller
design metodology is described and the results of the comparison
with random early detection (RED), tail drop, and PI controller
are presented
Photonic circuits for generating modal, spectral, and polarization entanglement
We consider the design of photonic circuits that make use of Ti:LiNbO
diffused channel waveguides for generating photons with various combinations of
modal, spectral, and polarization entanglement. Down-converted photon pairs are
generated via spontaneous optical parametric down-conversion (SPDC) in a
two-mode waveguide. We study a class of photonic circuits comprising: 1) a
nonlinear periodically poled two-mode waveguide structure, 2) a set of
single-mode and two-mode waveguide-based couplers arranged in such a way that
they suitably separate the three photons comprising the SPDC process, and, for
some applications, 3) a holographic Bragg grating that acts as a dichroic
reflector. The first circuit produces frequency-degenerate down-converted
photons, each with even spatial parity, in two separate single-mode waveguides.
Changing the parameters of the elements allows this same circuit to produce two
nondegenerate down-converted photons that are entangled in frequency or
simultaneously entangled in frequency and polarization. The second photonic
circuit is designed to produce modal entanglement by distinguishing the photons
on the basis of their frequencies. A modified version of this circuit can be
used to generate photons that are doubly entangled in mode number and
polarization. The third photonic circuit is designed to manage dispersion by
converting modal, spectral, and polarization entanglement into path
entanglement
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Mapping combined wildfire and heat stress hazards to improve evidence-based decision making
Heat stress and forest fires are often considered highly correlated hazards as extreme temperatures play a key role in both occurrences. This commonality can influence how civil protection and local responders deploy resources on the ground and could lead to an underestimation of potential impacts, as people could be less resilient when exposed to multiple hazards. In this work, we provide a simple methodology to identify areas prone to concurrent hazards, exemplified with, but not limited to, heat stress and fire danger. We use the combined heat and forest fire event that affected Europe in June 2017 to demonstrate that the methodology can be used for analysing past events as well as making predictions, by using reanalysis and medium-range weather forecasts, respectively. We present new spatial layers that map the combined danger and make
suggestions on how these could be used in the context of a Multi-Hazard Early Warning System. These products could be particularly valuable in disaster risk reduction and emergency response management, particularly for civil protection, humanitarian agencies and other first responders whose role is to identify priorities during pre-interventions and emergencies
Women's Knowledge, Attitudes and Behavior about Maternal Risk Factors in Pregnancy
BACKGROUND:
The aims of this study were to assess the levels of knowledge, attitudes and behaviors of women about the main maternal risk factors in pregnancy and to identify the factors linked to the main outcomes of interest.
MATERIALS AND METHODS:
A cross-sectional survey was conducted in 513 pregnant women randomly selected from the gynecological ambulatory services of five hospitals located in Naples, Italy.
RESULTS:
Only 42% of women correctly knew all the main maternal risk factors in pregnancy (alcohol, smoking, passive smoking and obesity). Only 21.7% of women were very worried about causing harm to the fetus or child with their risk behaviors, and 22.3% of women reported smoking during pregnancy. Approximately one-third of women (28.9%) reported regularly drinking alcohol before pregnancy and 74.8% of these women reported stopping drinking alcohol during pregnancy. However, only 27.3% of women who were drinking alcohol during pregnancy had the intention of stopping. Only 43.7% of women indicated that during ambulatory gynecological examinations they received information from physicians about the possible damage resulting from all the main risk factors in pregnancy (alcohol, smoking, passive smoking and obesity).
CONCLUSION:
The results indicate that pregnant women lack knowledge regarding the main maternal risk factors. Pregnant women claim to receive little information during gynecological examinations and, therefore, some continue to smoke and drink alcohol during pregnancy. Our results suggest an urgent need for the design of interventions to improve women's levels of knowledge and to promote appropriate behavior in relation to the major risk factors in pregnancy
Extracting Touristic Information from Online Image Collections
In this paper, we present a Geographical
Information Retrieval system, which aims to automatically
extract and analyze touristic information from photos of
online image collections (in our case of study Flickr). Our
system collect all the photos, and the related information,
that are associated to a specific city. We then use Google
Maps service to geolocate the retrieved photos, and finally
we analyze geo-referenced data to obtain our goals: 1)
determining and locating the most interesting places of the
city, i.e. the most visited locations, and 2) reconstructing
touristic routes of the users visiting the city. Information is
filtered by using a set of constraints, which we apply to select
only the users that reasonably are tourists visiting the city.
Tests were performed on an Italian city, Palermo, that is rich
in artistic and touristic attractions, but preliminary tests
showed that our technique could successfully be applied to
any city in the world with a reasonable number of touristic
landmarks
Knowledge, Attitudes, and Practices of Avian Influenza, Poultry Workers, Italy
We asked Italian poultry workers about knowledge, attitudes, and practices regarding avian influenza. It was perceived to be a low occupational hazard, and wearing protective equipment and handwashing were not routine practices. Knowledge of transmission and preventive measures should be improved. Employers and health professionals should provide more effective information
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