4,726 research outputs found
Prototype of non-genetically modified soybean tracking system using blockchain technology.
Genetically Modified Organisms (GMO) soybean is a soybean whose genetic material has been modified using genetic engineering techniques. GMO defenders say that this technology reduces the cost of food and helps producers deal with pests and diseases more safely. On the opposite consumers and environmental groups argue that transgenic crops drive higher use of pesticides. Because of this, there is a specific market for non-GMO crops. Some companies that export to Asia and Europe markets pay a premium for non-GMO soybean. But this non-GMO soybean must have a certificate indicating their purity, i.e., which there is not a mix with GMO soybean. The aim of this work is the development of a prototype of a system to track non-GMO soybean to guarantee its purity. The prototype developed in this work used blockchain technology. The choice for blockchain was because it is very secure against tampering, and, also is a distributed system proper for applications like this, which will track the non-GMO soybean from cultivation to product delivery
Gerenciamento de redes de computadores utilizando CACTI.
Este documento foi concebido com o intuito de ressaltar a importância do acompanhamento da disponibilidade dos recursos de uma rede de computadores. O presente trabalho consiste de um procedimento para a implementação da ferramenta CACTI, que é um software para monitoramento da disponibilidade de máquinas e serviços de uma rede de computadores, e também para a inserção dos ativos de rede que se deseja gerenciar por meio dessa ferramenta. Antes da apresentação da ferramenta CACTI, é feita uma breve explanação de alguns entre os muitos softwares de monitoramento existentes no mercado. Este trabalho destina-se a facilitar a tarefa de gerenciamento de uma rede de computadores a todos os usuários, que de alguma forma necessitem, de forma clara e objetiva, saber da disponibilidade de seus recursos, seja de forma imediata ou ao longo de um período de tempo.bitstream/item/31513/1/doc105-10.pd
Building a multi-hop wireless sensor network for water level monitoring.
Abstract-Wireless Sensor Networks (WSN) are very useful for data acquisition in harsh environments or where the maintenance of wired infrastructure would not be viable. Despite of these advantages WSN nodes have a limited range ratio thus to collect data on long distance is necessary to construct a path with many relay nodes to reach the destination. Another limitation of these networks is that they often rely on batteries to operate, which can cause a serious limitation in the network lifetime. In this work it was developed a solution based on a Multi-hop WSN to collect data on long distance, and, also some strategies such as 'sleep schedule', 'data aggregation' and 'hub polling' were implemented to extend the WSN lifetime. This could be done by modifications at RFBee Libraries that reinforces the importance of flexibility and portability of this device
Symmetries of the Dirac operators associated with covariantly constant Killing-Yano tensors
The continuous and discrete symmetries of the Dirac-type operators produced
by particular Killing-Yano tensors are studied in manifolds of arbitrary
dimensions. The Killing-Yano tensors considered are covariantly constant and
realize certain square roots of the metric tensor. Such a Killing-Yano tensor
produces simultaneously a Dirac-type operator and the generator of a
one-parameter Lie group connecting this operator with the standard Dirac one.
The Dirac operators are related among themselves through continuous or discrete
transformations. It is shown that the groups of the continuous symmetry can be
only U(1) and SU(2), specific to (hyper-)Kahler spaces, but arising even in
cases when the requirements for these special geometries are not fulfilled. The
discrete symmetries are also studied obtaining the discrete groups Z_4 and Q.
The briefly presented examples are the Euclidean Taub-NUT space and the
Minkowski spacetime.Comment: 27 pages, latex, no figures, final version to be published in Class.
Quantum Gravit
Evolution of the discrepancy between a universe and its model
We study a fundamental issue in cosmology: Whether we can rely on a
cosmological model to understand the real history of the Universe. This
fundamental, still unresolved issue is often called the ``model-fitting problem
(or averaging problem) in cosmology''. Here we analyze this issue with the help
of the spectral scheme prepared in the preceding studies.
Choosing two specific spatial geometries that are very close to each other,
we investigate explicitly the time evolution of the spectral distance between
them; as two spatial geometries, we choose a flat 3-torus and a perturbed
geometry around it, mimicking the relation of a ``model universe'' and the
``real Universe''. Then we estimate the spectral distance between them and
investigate its time evolution explicitly. This analysis is done efficiently by
making use of the basic results of the standard linear structure-formation
theory.
We observe that, as far as the linear perturbation of geometry is valid, the
spectral distance does not increase with time prominently,rather it shows the
tendency to decrease. This result is compatible with the general belief in the
reliability of describing the Universe by means of a model, and calls for more
detailed studies along the same line including the investigation of wider class
of spacetimes and the analysis beyond the linear regime.Comment: To be published in Classical and Quantum Gravit
Partial ferromagnetic ordering and indirect exchange interaction in spatially anisotropic kagome antiferromagnet Cs_2Cu_3CeF_{12}
We report the crystal structure and unconventional magnetic ordering of
Cs_2Cu_3CeF_{12}, which is composed of buckled kagome lattice of Cu^{2+} ions.
The exchange network in the buckled kagome lattice is fairly anisotropic, so
that the present spin system can be divided into two subsystems: alternating
Heisenberg chains with strong antiferromagnetic exchange interactions and
dangling spins. Although the direct exchange interactions between neighboring
spins were found to be all antiferromagnetic, ferromagnetic magnetic ordering
of the dangling spins was observed. Magnetization exhibits a plateau at
one-third of the saturation magnetization. These observations can be understood
in terms of the indirect interaction between dangling spins mediated by the
chain spin.Comment: 4 pages, 3 figure
Otimização e tolerância a falhas em uma rede de sensores sem fio.
Resumo. Este artigo apresenta uma proposta de solução para otimização e tolerância a falhas para uma Rede de Sensores Sem Fio, que são redes próprias para coletar dados em ambientes inóspitos, hostis, de difícil acesso ou de custo de infraestrutura elevados. Essas redes tem atualmente muitas restrições em seu tempo de vida, dada a pouca autonomia da carga de suas baterias, destaca-se, portanto, a importância de sua otimização. Discute-se também a importância da redundância de recursos para garantia de coleta de dados. A solução proposta é uma implementação factível e de baixo custo, como considera-se que deva ser uma rede para esses fins e com essas características
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Marco Polo: near Earth object sample return mission
Marco Polo is a joint European-Japanese mission of sample return from a Near Earth Object. The Marco Polo proposal was submitted to ESA on July 2007 in the framework of the Cosmic Vision 2015-2025 context, and on October 2007 passed the first evaluation process. The primary objectives of this mission is to visit a primitive NEO, belonging to a class that cannot be related to known meteorite types, to characterize it at multiple scales, and to bring samples back to Earth. Marco Polo will give us the first opportunity for detailed laboratory study of the most primitive materials that formed the planets. This will allow us to improve our knowledge on the processes which governed the origin and early evolution of the Solar System, and possibly of the life on Earth
Conserved Matter Superenergy Currents for Orthogonally Transitive Abelian G2 Isometry Groups
In a previous paper we showed that the electromagnetic superenergy tensor,
the Chevreton tensor, gives rise to a conserved current when there is a
hypersurface orthogonal Killing vector present. In addition, the current is
proportional to the Killing vector. The aim of this paper is to extend this
result to the case when we have a two-parameter Abelian isometry group that
acts orthogonally transitive on non-null surfaces. It is shown that for
four-dimensional Einstein-Maxwell theory with a source-free electromagnetic
field, the corresponding superenergy currents lie in the orbits of the group
and are conserved. A similar result is also shown to hold for the trace of the
Chevreton tensor and for the Bach tensor, and also in Einstein-Klein-Gordon
theory for the superenergy of the scalar field. This links up well with the
fact that the Bel tensor has these properties and the possibility of
constructing conserved mixed currents between the gravitational field and the
matter fields.Comment: 15 page
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