6,665 research outputs found
Social distancing strategies against disease spreading
The recurrent infectious diseases and their increasing impact on the society
has promoted the study of strategies to slow down the epidemic spreading. In
this review we outline the applications of percolation theory to describe
strategies against epidemic spreading on complex networks. We give a general
outlook of the relation between link percolation and the
susceptible-infected-recovered model, and introduce the node void percolation
process to describe the dilution of the network composed by healthy individual,
, the network that sustain the functionality of a society. Then, we survey
two strategies: the quenched disorder strategy where an heterogeneous
distribution of contact intensities is induced in society, and the intermittent
social distancing strategy where health individuals are persuaded to avoid
contact with their neighbors for intermittent periods of time. Using
percolation tools, we show that both strategies may halt the epidemic
spreading. Finally, we discuss the role of the transmissibility, , the
effective probability to transmit a disease, on the performance of the
strategies to slow down the epidemic spreading.Comment: to be published in "Perspectives and Challenges in Statistical
Physics and Complex Systems for the Next Decade", Word Scientific Pres
Experimental pre-assessing entanglement in Gaussian states mixing
We suggest and demonstrate a method to assess entanglement generation schemes
based on mixing of Gaussian states at a beam splitter (BS). Our method is based
on the fidelity criterion and represents a tool to analyze the effect of losses
and noise before the BS in both symmetric and asymmetric channels with and
without thermal effects. More generally, our scheme allows one to pre-assess
entanglement resources and to optimize the design of BS-based schemes for the
generation of continuous variable entanglement.Comment: 10 pages, 15 figure
Immunization strategy for epidemic spreading on multilayer networks
In many real-world complex systems, individuals have many kind of
interactions among them, suggesting that it is necessary to consider a layered
structure framework to model systems such as social interactions. This
structure can be captured by multilayer networks and can have major effects on
the spreading of process that occurs over them, such as epidemics. In this
Letter we study a targeted immunization strategy for epidemic spreading over a
multilayer network. We apply the strategy in one of the layers and study its
effect in all layers of the network disregarding degree-degree correlation
among layers. We found that the targeted strategy is not as efficient as in
isolated networks, due to the fact that in order to stop the spreading of the
disease it is necessary to immunize more than the 80 % of the individuals.
However, the size of the epidemic is drastically reduced in the layer where the
immunization strategy is applied compared to the case with no mitigation
strategy. Thus, the immunization strategy has a major effect on the layer were
it is applied, but does not efficiently protect the individuals of other
layers.Comment: 8 pages, 2 figure
Tunable non-Gaussian resources for continuous-variable quantum technologies
We introduce and discuss a set of tunable two-mode states of
continuous-variable systems, as well as an efficient scheme for their
experimental generation. This novel class of tunable entangled resources is
defined by a general ansatz depending on two experimentally adjustable
parameters. It is very ample and flexible as it encompasses Gaussian as well as
non-Gaussian states. The latter include, among others, known states such as
squeezed number states and de-Gaussified photon-added and photon-subtracted
squeezed states, the latter being the most efficient non-Gaussian resources
currently available in the laboratory. Moreover, it contains the classes of
squeezed Bell states and even more general non-Gaussian resources that can be
optimized according to the specific quantum technological task that needs to be
realized. The proposed experimental scheme exploits linear optical operations
and photon detections performed on a pair of uncorrelated two--mode Gaussian
squeezed states. The desired non-Gaussian state is then realized via ancillary
squeezing and conditioning. Two independent, freely tunable experimental
parameters can be exploited to generate different states and to optimize the
performance in implementing a given quantum protocol. As a concrete instance,
we analyze in detail the performance of different states considered as
resources for the realization of quantum teleportation in realistic conditions.
For the fidelity of teleportation of an unknown coherent state, we show that
the resources associated to the optimized parameters outperform, in a
significant range of experimental values, both Gaussian twin beams and
photon-subtracted squeezed states.Comment: 13 pages, 7 figure
Slow epidemic extinction in populations with heterogeneous infection rates
We explore how heterogeneity in the intensity of interactions between people
affects epidemic spreading. For that, we study the
susceptible-infected-susceptible model on a complex network, where a link
connecting individuals and is endowed with an infection rate
proportional to the intensity of their contact
, with a distribution taken from face-to-face experiments
analyzed in Cattuto (PLoS ONE 5, e11596, 2010). We find an extremely
slow decay of the fraction of infected individuals, for a wide range of the
control parameter . Using a distribution of width we identify two
large regions in the space with anomalous behaviors, which are
reminiscent of rare region effects (Griffiths phases) found in models with
quenched disorder. We show that the slow approach to extinction is caused by
isolated small groups of highly interacting individuals, which keep epidemic
alive for very long times. A mean-field approximation and a percolation
approach capture with very good accuracy the absorbing-active transition line
for weak (small ) and strong (large ) disorder, respectively
Pengenalan Chord pada Alat Musik Gitar Menggunakan CodeBook dengan Teknik Ekstraksi Ciri MFCC
Human auditory system is capable of extracting rich and meaningful data from complex audio signal. To recognize chord sequences that played in some kind of music is not an easy task. People need big effort to train their sense of hearing so they can recognize that kind sound of chords. This condition is also valid in a computer system. Finding the key and labeling the chords automatically from music are great use for those who want to do harmonic analysis of music. Hence automatic chord recognition has been a topic of interest in the context of Music Information Retrieval (MIR) for several years, and attempts have been made in implementing such systems using well understood signal processing and pattern recognition techniques. This research is about to recognize the sound of chord that played and recorded by guitar instrument. There are 24 major-minor chords that used in this research. MFCC is used as feature extraction and the number of coefficient cepstral that used are 13 and 26. Each chord signal that has been extracted then clustered using K-means algorithm with 8, 12, 16, 20, 24, 28, 32 k numbers to create codebook that use as a model of each chord. For the recognition process, there are two methods that used in this research, unstructured recognition and structured recognition. For the result, this research produces two kinds model of codebook that are codebook with 13 coefficients and codebook with 26 coefficients. Both types of codebook show a good result with accuracy level above 88%. The best result yielded from USAge of 26 coefficient cepstral with structured recognition. It's accuracy level reach 97%. Hence the USAge of 26 coefficient cepstral is better than the USAge of 13 coefficient cepstral with difference of accuration level is about 7%. This research also shows the affectation of the numbers k-means that used. An increasing accuration level shown by increasing the amount of k-cluster
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