10,005 research outputs found
IoT system for the validation of conditions in shipping couriers
Online activity has increased over the years and has become a staple in modern society. With it, online shopping businesses have become more common, as well as the number of Internet of Things (IoT) devices. As the shopping experience becomes less personal, some people try to exploit the system causing online businesses to increasingly suffer from return frauds. This paper proposes a solution to this problem, integrating IoT and image processing. The proposed system uses IoT to verify package conditions in courier services, and a database to monitor shipments. The methodology followed for development is described, including the research models, research questions and hypothesis. Development was based on a literature review conducted in order to understand what has been done in the area of logistics services, and what equipment and tools were used for these projects. In addition, the system’s design and architecture are described, giving insight to each components’ function in the system. The system is then implemented to simulate a realworld scenario and tests are carried out. The results of the tests are gathered and analyzed to fine-tune the system. Finally, conclusions are drawn out on the system’s capability of achieving the goals and requirements established before development.info:eu-repo/semantics/acceptedVersio
Time evolution towards q-Gaussian stationary states through unified Ito-Stratonovich stochastic equation
We consider a class of single-particle one-dimensional stochastic equations
which include external field, additive and multiplicative noises. We use a
parameter which enables the unification of the traditional
It\^o and Stratonovich approaches, now recovered respectively as the
and particular cases to derive the associated Fokker-Planck
equation (FPE). These FPE is a {\it linear} one, and its stationary state is
given by a -Gaussian distribution with , where characterizes the
strength of the confining external field, and is the (normalized)
amplitude of the multiplicative noise. We also calculate the standard kurtosis
and the -generalized kurtosis (i.e., the standard
kurtosis but using the escort distribution instead of the direct one). Through
these two quantities we numerically follow the time evolution of the
distributions. Finally, we exhibit how these quantities can be used as
convenient calibrations for determining the index from numerical data
obtained through experiments, observations or numerical computations.Comment: 9 pages, 2 figure
Oxidative DNA damage protection and repair by polyphenolic compounds in PC12 cells
Biological systems are frequently exposed to excessive reactive oxygen species, causing a disturbance in the
cells natural antioxidant defence systems and resulting in damage to all biomolecules, including nucleic
acids. In fact, oxidative DNA damage is described as the type of damage most likely to occur in neuronal cells.
In this study, three polyphenolic compounds, luteolin, quercetin and rosmarinic acid, were investigated for
their protective effects against oxidative DNA damage induced in PC12 cells, a neuronal cell model. Although
luteolin and quercetin prevented the formation of strand breaks to a greater extent than rosmarinic acid, this
last one presented the highest capacity to repair strand breaks formation. In addition, rosmarinic acid was
the only compound tested that increased the repair of oxidized nucleotidic bases induced with the
photosensitizer compound [R]-1-[(10-chloro-4-oxo-3-phenyl-4H-benzo[a]quinolizin-1-yl) carbonyl]-2-pyrrolidine-
methanol (Ro 19-8022). The activity of repair enzymes was indicated by the in vitro base excision
repair assay, using a cell-free extract obtained from cells previously treated with the compounds to incise
DNA. The protective effect of rosmarinic acid was further confirmed by the increased expression of OGG1
repair gene, observed through real time RT-PCR. The data obtained is indicative that rosmarinic acid seems to
act on the intracellular mechanisms responsible for DNA repair, rather than by a direct effect on reactive
oxygen species scavenging, as deducted from the effects observed for luteolin and quercetin. Therefore, these
results suggest the importance of these polyphenols, and in particular rosmarinic acid, as protectors of
oxidative stress-induced DNA damage that commonly occurs in several pathological conditions, such as
neurodegenerative diseases.Fundação para a Ciência e a Tecnologia (FCT) - bolsa SFRH/BD/17174/2004
Magnetism and Electronic Correlations in Quasi-One-Dimensional Compounds
In this contribution on the celebration of the 80th birthday anniversary of
Prof. Ricardo Ferreira, we present a brief survey on the magnetism of
quasi-one-dimensional compounds. This has been a research area of intense
activity particularly since the first experimental announcements of magnetism
in organic and organometallic polymers in the mid 80s. We review experimental
and theoretical achievements on the field, featuring chain systems of
correlated electrons in a special AB2 unit cell structure present in inorganic
and organic compounds
Entropy production and Kullback-Leibler divergence between stationary trajectories of discrete systems
The irreversibility of a stationary time series can be quantified using the
Kullback-Leibler divergence (KLD) between the probability to observe the series
and the probability to observe the time-reversed series. Moreover, this KLD is
a tool to estimate entropy production from stationary trajectories since it
gives a lower bound to the entropy production of the physical process
generating the series. In this paper we introduce analytical and numerical
techniques to estimate the KLD between time series generated by several
stochastic dynamics with a finite number of states. We examine the accuracy of
our estimators for a specific example, a discrete flashing ratchet, and
investigate how close is the KLD to the entropy production depending on the
number of degrees of freedom of the system that are sampled in the
trajectories.Comment: 14 pages, 7 figure
Uso eficiente da água de irrigação e da energia elétrica em cultura de milho sob pivô central num plantio comercial em Várzea da Palma, MG.
The motion of two masses coupled to a massive spring
We discuss the classical motion of a spring of arbitrary mass coupled to two
arbitrary massive blocks attached at its ends. A general approach to the
problem is presented and some general results are obtained. Examples for which
a simple elastic function can be inferred are discussed and the normal modes
and normal frequencies obtained. An approximation procedure to the evaluation
of the normel frequencies in the case of uniform elastic function and mass
density is also discussed.Comment: Standard Latex file plus three eps figure
Many-body system with a four-parameter family of point interactions in one dimension
We consider a four-parameter family of point interactions in one dimension.
This family is a generalization of the usual -function potential. We
examine a system consisting of many particles of equal masses that are
interacting pairwise through such a generalized point interaction. We follow
McGuire who obtained exact solutions for the system when the interaction is the
-function potential. We find exact bound states with the four-parameter
family. For the scattering problem, however, we have not been so successful.
This is because, as we point out, the condition of no diffraction that is
crucial in McGuire's method is not satisfied except when the four-parameter
family is essentially reduced to the -function potential.Comment: 8 pages, 4 figure
- …