Abstract: In this work it is proposed a new tool to measure crop water-content using RF communica... more Abstract: In this work it is proposed a new tool to measure crop water-content using RF communication signals from nodes of a wireless sensor network. Accurate measurement is obtained combining data from many nodes spread in the crop field. The mathematical model of the measuring process is discussed and experimental data are presented supporting the model.
This paper presents a novel signal propagation model of wireless sensor network (WSN) for outdoo... more This paper presents a novel signal propagation model of wireless sensor network (WSN) for outdoor open environments. This model can be used in simulators and also in WSN services as localization discovery. The model here proposed produces results with higher accuracy when compared to the models existing in the literature. It is based on the existing double path propagation model (tworay), but differently from the previous works, it takes into account the directivity of the antennas and the variable reflectivity index of the soil. Experiments confirmed the outstanding results of our propagation model
A medida da intensidade de sinal de radio nas comunicacoes em uma rede de sensores sem fios (RSSF... more A medida da intensidade de sinal de radio nas comunicacoes em uma rede de sensores sem fios (RSSF) e utilizada para diversas funcoes vitais, especialmente para a localizacao dos nos sensores dentro da rede e para a estimacao da qualidade de suas ligacoes. Este trabalho apresenta uma descricao de algumas arquiteturas de radio utilizados por nos sensores comerciais e os metodos empregados por estes para a medicao da intensidade do sinal captado pelo receptor. E sugerido um tratamento estatistico dessas medicoes e sao apresentados resultados experimentais que confirmam esta abordagem.
Apresenta-se aqui o projeto de um sistema computacional para aquisicao e analise de sinais de ten... more Apresenta-se aqui o projeto de um sistema computacional para aquisicao e analise de sinais de tensao e corrente da rede eletrica, utilizando a decomposicao em Series de Fourier. O sistema desenvolvido compreende uma placa de aquisicao de dados ligada a um microcomputador, e um programa que faz o controle da placa e a analise dos dados.
In this work it is proposed a new tool to measure crop water-content using RF communication signa... more In this work it is proposed a new tool to measure crop water-content using RF communication signals from nodes of a wireless sensor network. Accurate measurement is obtained combining data from many nodes spread in the crop field. The mathematical model of the measuring process is discussed and experimental data are presented supporting the model.
This paper presents a study on two single-phase switching AC/DC converters used to supply energy ... more This paper presents a study on two single-phase switching AC/DC converters used to supply energy to a resistive variable load with constant voltage output, obtaining High Power Factor input with Low Harmonic Distortion. The dynamic and Steady-State behavior of two DC power suplies is analysed by their State-Equations and Transfer Functions. The Capacitive Idling Cuk Converter [1] [2] which is used to obtain both High Power Factor input, and constant voltage output, is studied, as well as the commonly used pre-regulator Boost and regulator Buck (named Boost-Buck set), coupled, operating in continuous current conduction mode (CCM). Low power prototypes were built using the same components in both converters, and practical results were obtained to compare them. A isolated Boost-Buck set was built, using a Forward converter in place of the Buck converter.
Wireless sensor networks employ duty-cycles to save energy, with the cost of enlargement of end-t... more Wireless sensor networks employ duty-cycles to save energy, with the cost of enlargement of end-to-end latency. Cross-layer protocols that use anycast medium access control achieve latency reduction in asynchronous duty-cycled wireless sensor networks (WSNs). A series of strobed preambles is sent in order to achieve rendezvous with the next relay, selected from a forwarding candidate set (FCS). This paper proposes PAX-MAC: Pramble Ahead Cross-layer Medium Access Control. It is a novel anycast protocol for low latency packet propagation in duty-cycled WSNs. In PAX-MAC, preambles propagate ahead of data packet, prospecting the route towards sink node, while the message is sent some hops later. Simultaneous propagation of preambles and data packets provides latency reduction. The cardinality of FCS determines the average preamble propagation speed, which is lower bounded by data packet propagation speed. Differently from other approaches, our protocol takes the data packet size into ac...
UFLA - Federal University of Lavras - Brazil DCC - Department of Computer Science 1(giacomin,lcor... more UFLA - Federal University of Lavras - Brazil DCC - Department of Computer Science 1(giacomin,lcorreia,tales)@dcc.ufla.br 3(viniciusfs,jlucasps)@comp.ufla.br DEG - Department of Engeneering [email protected] ... Abstract. This paper presents a novel signal ...
Abstract: In this work it is proposed a new tool to measure crop water-content using RF communica... more Abstract: In this work it is proposed a new tool to measure crop water-content using RF communication signals from nodes of a wireless sensor network. Accurate measurement is obtained combining data from many nodes spread in the crop field. The mathematical model of the measuring process is discussed and experimental data are presented supporting the model.
This paper presents a novel signal propagation model of wireless sensor network (WSN) for outdoo... more This paper presents a novel signal propagation model of wireless sensor network (WSN) for outdoor open environments. This model can be used in simulators and also in WSN services as localization discovery. The model here proposed produces results with higher accuracy when compared to the models existing in the literature. It is based on the existing double path propagation model (tworay), but differently from the previous works, it takes into account the directivity of the antennas and the variable reflectivity index of the soil. Experiments confirmed the outstanding results of our propagation model
A medida da intensidade de sinal de radio nas comunicacoes em uma rede de sensores sem fios (RSSF... more A medida da intensidade de sinal de radio nas comunicacoes em uma rede de sensores sem fios (RSSF) e utilizada para diversas funcoes vitais, especialmente para a localizacao dos nos sensores dentro da rede e para a estimacao da qualidade de suas ligacoes. Este trabalho apresenta uma descricao de algumas arquiteturas de radio utilizados por nos sensores comerciais e os metodos empregados por estes para a medicao da intensidade do sinal captado pelo receptor. E sugerido um tratamento estatistico dessas medicoes e sao apresentados resultados experimentais que confirmam esta abordagem.
Apresenta-se aqui o projeto de um sistema computacional para aquisicao e analise de sinais de ten... more Apresenta-se aqui o projeto de um sistema computacional para aquisicao e analise de sinais de tensao e corrente da rede eletrica, utilizando a decomposicao em Series de Fourier. O sistema desenvolvido compreende uma placa de aquisicao de dados ligada a um microcomputador, e um programa que faz o controle da placa e a analise dos dados.
In this work it is proposed a new tool to measure crop water-content using RF communication signa... more In this work it is proposed a new tool to measure crop water-content using RF communication signals from nodes of a wireless sensor network. Accurate measurement is obtained combining data from many nodes spread in the crop field. The mathematical model of the measuring process is discussed and experimental data are presented supporting the model.
This paper presents a study on two single-phase switching AC/DC converters used to supply energy ... more This paper presents a study on two single-phase switching AC/DC converters used to supply energy to a resistive variable load with constant voltage output, obtaining High Power Factor input with Low Harmonic Distortion. The dynamic and Steady-State behavior of two DC power suplies is analysed by their State-Equations and Transfer Functions. The Capacitive Idling Cuk Converter [1] [2] which is used to obtain both High Power Factor input, and constant voltage output, is studied, as well as the commonly used pre-regulator Boost and regulator Buck (named Boost-Buck set), coupled, operating in continuous current conduction mode (CCM). Low power prototypes were built using the same components in both converters, and practical results were obtained to compare them. A isolated Boost-Buck set was built, using a Forward converter in place of the Buck converter.
Wireless sensor networks employ duty-cycles to save energy, with the cost of enlargement of end-t... more Wireless sensor networks employ duty-cycles to save energy, with the cost of enlargement of end-to-end latency. Cross-layer protocols that use anycast medium access control achieve latency reduction in asynchronous duty-cycled wireless sensor networks (WSNs). A series of strobed preambles is sent in order to achieve rendezvous with the next relay, selected from a forwarding candidate set (FCS). This paper proposes PAX-MAC: Pramble Ahead Cross-layer Medium Access Control. It is a novel anycast protocol for low latency packet propagation in duty-cycled WSNs. In PAX-MAC, preambles propagate ahead of data packet, prospecting the route towards sink node, while the message is sent some hops later. Simultaneous propagation of preambles and data packets provides latency reduction. The cardinality of FCS determines the average preamble propagation speed, which is lower bounded by data packet propagation speed. Differently from other approaches, our protocol takes the data packet size into ac...
UFLA - Federal University of Lavras - Brazil DCC - Department of Computer Science 1(giacomin,lcor... more UFLA - Federal University of Lavras - Brazil DCC - Department of Computer Science 1(giacomin,lcorreia,tales)@dcc.ufla.br 3(viniciusfs,jlucasps)@comp.ufla.br DEG - Department of Engeneering [email protected] ... Abstract. This paper presents a novel signal ...
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Papers by João Giacomin