Abstract Numerical and experimental analysis of visible light communication (VLC) systems based on orthogonal chirp division multiplexing (OCDM) and orthogonal frequency division multiplexing (OFDM) are presented in this paper. Unlike most of the related publications, in this work we numerically compared OCDM and OFDM based VLC systems with the same equalization process, i.e., employing an one tap equalizer (OTE) in both systems. Simulation results in line-of-sight VLC channels show that both systems have the same performance when baseband multicarrier signals are used. The impact of the optical modulation index and the bias current of a previously characterized light-emitting diode were also evaluated. Nevertheless, the experimental demonstrations, in which bandpass signals were used due to the bandpass characteristic of the exploited setup, show that OFDM-based system outperforms the VLC links with OCDM signals, when the OTE equalizer is used in both systems. The performance of the OCDM-based system was improved by using a zero forcing frequency domain equalizer. (VLC (OCDM (OFDM paper publications process ie i e i.e. (OTE lineofsight line sight lightemitting emitting evaluated Nevertheless demonstrations setup OFDMbased OCDMbased i.e

Abstract This paper presents measurements at a mock-up medium voltage network to verify the feasibility of Broadband Power Line Communication (BPLC). We use the data extracted within the frequency range 2 − 30 MHz to characterize a MIMO PLC network using different phase combinations, defining the best and worst use case scenarios. The empirical data shows that not only phases directly connected for input-output can be used, but also that we can exploit the coupling between phases to transmit and receive data, therefore creating a dynamic PLC network which will depend on the characteristics of the power grid. By making use of transmission line theory, we also demonstrate how we can mitigate the reflections by measuring the input impedance of the network to allow better use of the bandwidth available for BPLC operation.

Abstract The growth of urban centers has a major impact on our lives and on our society, one of which is the increase in the vehicle fleet, which in turns is a major offender in increasing road congestion, pollution, accidents, theft of vehicles, among others. With a focus on minimizing problems with theft of vehicles in an urban environment this paper proposes a low cost Internet of Things for smart surveillance system. The central element of the system is attached to a vehicle that travels in an urban environment making Automatic License Plate Recognition of the vehicles license plates in front of it. The information collected is forwarded to a cloud service that is responsible for monitoring restricted vehicle license plates to view positioning, time, date and statistics related to restricted vehicle license plates. Experimental results obtained in test paths in an urban environment show promising results. The low cost of implementing the system allows it to be scaled to a fleet of vehicles, making it possible to build a mobile intelligent surveillance network, amplifying the monitoring capacity of an urban area.

Abstract In this work, we introduce a new concept of frequency interleaving applied to passive optical networks based in Dense Wavelength Division Multiplexing (DWDM). In order to explore colorless ONUs approach, a single and centralized optical source is used to create the interleaved wavelengths for the downstream and upstream path. In this case, frequency comb generation implemented by recirculating frequency shifting technique allowed the creation of all the wavelengths used in each path. The reception operation is accomplished by introducing, at the ONU side, a combination of a set of optical passive elements. The system with 4 × 12.5 Gbit/s NRZ-OOK (Not Return to Zero - On-Off Keying) modulation format were simulated through 20 km of standard single mode fiber link in both transmission paths. In order to guarantee a high quality optical frequency comb source, the optical carrier-to-noise-ratio (OCNR) was evaluated as well as BER (bit error rate), to analyze the system performance. All devices models and simulations were performed in Matlab environment.

Abstract Here we report a simple analytical technique to model a Mach-Zehnder fiber optic interferometric sensors that allow us to predict and calculate via computer simulations parameters that are not easily obtained experimentally. This model was calibrated and compared with experimental data using a 120 mm sensor for measurements of temperature, refractive index and water level. For instance, we were able to calculate the effects on the cladding effective index caused by the variation of those physical parameters. Moreover, this analysis could further our understanding of such sensors and allow us to make predictions about their use in different applications and even their behavior with different sensing lengths.

RESUMO A mecanização da colheita de cana-de-açúcar vem crescendo nos estados produtores, devido à necessidade de erradicação da queima pré-colheita em toda área canavieira até 2017. Todavia, o sistema de corte basal das colhedoras ainda se mostra ineficiente, interferindo diretamente na qualidade da matéria-prima e comprometendo a longevidade do canavial. Neste contexto, objetivou-se neste trabalho avaliar os índices danos e de abalos causados às soqueiras de cana-de-açúcar por três modelos de facas utilizadas no corte de base das colhedoras, sendo duas facas revestidas com carbeto de tungstênio e outra sem revestimento, com diferentes angulações. O delineamento utilizado foi inteiramente casualizado, em faixas, com o número de repetições definidas em função do tempo e do modo de uso das facas. Foram utilizados como indicadores de qualidade as variáveis altura de corte, os índices de danos e de abalos das soqueiras. Os índices de danos e de abalos às soqueiras apresentam influência em função do modelo de faca utilizado. A maior qualidade da operação para o índice de danos e de abalos às soqueiras ocorre para as facas revestidas com ângulo de 13º.

ABSTRACT Mechanisation of the sugarcane harvest has been on the increase in those states where sugarcane is produced, because of the need to eradicate pre-harvest burning throughout the area of sugarcane plantation by 2017. However, the base cutting system of the harvesters is still proving inefficient, directly interfering in the quality of the raw material and compromising the life of the plantation. The aim of this study therefore, was to evaluate the indices for damage and loss in ratoon sugarcane, for three types of knife used in base cutting in harvesters, using two knives coated with tungsten carbide and another uncoated, all at different angles. The experimental design was completely randomised into bands, with the number of replications defined as a function of the time and mode of use of the knives. The variables cutting height and the indices of damage and loss in the ratoon cane were used as quality indicators. The indices of damage and loss are influenced by the type of knife used. From the indices of damage and loss in the ratoon cane, the highest operating quality is seen with coated knives at an angle of 13º.

Abstract This paper presents a theoretical and computational study on the analysis of parameters for distributed temperature sensing in optical fibers, based on spontaneous Raman scattering effect. The parameters studied were the optical power level, the range of frequency modulation and the length of the sensor element, as well as the application of optical frequency domain reflectometry (OFDR). Two different approaches of reading temperature information from the backscattered signal were also tested. First, one considered the pulse response, and later the ratio between the amplitudes of the detected signals were taken. Such analysis has shown the second method is more efficient to detect the peak of hot spot temperature in the fiber. Spatial resolution equal to 0.96 m and a temperature resolution of 0.089 °C were achieved using singlemode fiber 30 meters long.

Abstract Nowadays, communication and networking technologies are essential for Oil & Gas industries in order to guarantee reliability, safety and low costs in the producing process. Information access and commands and set-points transmission from/to automation systems are challenging tasks mainly due to distributed production areas and hostile environments. This paper presents a field trial of broadband power line communication over an overhead medium voltage grid as a data transport employing 200 Mb/s BPL modems. Throughput, frequency response, physical speed and latency are some of the investigated network parameters. Experimental results obtained after propagation through 1.63 km of a multipath MV power grid reveal the viability of the BPL technology as an access network for video and automation data transport in onshore Oil & Gas industries.

With the increase in demand to Backbone networks, one became fundamental the application of new telecommunication technologies for efficient use of devices and optical links, such as xPSK modulations with dual polarization, dispersion compensating fibers, coherent detection and digital processing signals. Thus, network planning using analytical models have been proposed in the last years for this purpose. In this paper we propose the use of numerical simulations in wavelength-division multiplexing networks planning via a novel iterative method with high-performance processing, which does an analysis of the quality of transmission in transparent networks.

In this paper, we propose a hybrid methodology based on Graph-Coloring and Genetic Algorithm (GA) to solve the Wavelength Assignment (WA) problem in optical networks, impaired by physical layer effects. Our proposal was developed for a static scenario where the physical topology and traffic matrix are known a priori. First, we used fixed shortest-path routing to attend demand requests over the physical topology and the graph-coloring algorithm to minimize the number of necessary wavelengths. Then, we applied the genetic algorithm to solve WA. The GA finds the wavelength activation order on the wavelengths grid with the aim of reducing the Cross-Phase Modulation (XPM) effect; the variance due to the XPM was used as a function of fitness to evaluate the feasibility of the selected WA solution. Its performance is compared with the First-Fit algorithm in two different scenarios, and has shown a reduction in blocking probability up to 37.14% when considered both XPM and residual dispersion effects and up to 71.42% when only considered XPM effect. Moreover, it was possible to reduce by 57.14% the number of wavelengths.

Durante o processo de colheita mecanizada de cana-de-açúcar, o desgaste das facas do mecanismo de corte basal é fator diretamente relacionado com a qualidade do corte realizado pelas máquinas, sendo o emprego de ferramentas de controle de qualidade importantes no monitoramento deste processo. Assim, o presente trabalho, desenvolvido na região de Ribeirão Preto, teve por objetivo avaliar o desgaste das facas do corte basal e os danos causados às soqueiras na colheita mecanizada de cana-de-açúcar, sob a ótica do controle estatístico de qualidade (CEQ). O desgaste das facas foi quantificado por meio da perda de massa e de suas dimensões, enquanto a qualidade do corte foi avaliada pela altura e pelos danos às soqueiras, classificados visualmente em função do nível de dano causado. Os resultados obtidos mostraram que o desgaste das facas ocorreu de maneira mais acentuada em determinados períodos de utilização, porém mantendo-se dentro de padrões de controle. A altura de corte não foi afetada pelo desgaste das facas, mantendo-se dentro dos limites de qualidade desejáveis para a operação. Finalmente, os danos causados às soqueiras variaram entre si em função de cada face de corte das facas avaliadas, havendo predominância de determinadas classes de danos em cada face de corte, porém sempre se mantendo dentro dos padrões aceitáveis pelo controle estatístico.

During the sugarcane mechanized harvester process, the wear of base cutting knives is directly correlated to the quality of the cut made by the machines, and the use of quality control tools important in monitoring this process. Thus, the present study in Ribeirão Preto region aimed to assess the knives cut baseline and damage caused to wear brass knuckles in mechanized harvesting of cane raw sugar, from the viewpoint of statistical quality control (SQC). The wear of the knives was quantified by mass loss and its dimensions, while cutting quality was assessed by cutting height and damage to stumps visually classified according to the level of damage caused. The results showed that the wear of the knives was more pronounced in certain periods of use, but still within control standards. The cutting height was not affected by the wear of the knives, keeping within the limits of desirable quality for operation. Eventually damage the stumps ranged among themselves depending on each face of the cutting knives evaluated, and the predominance of certain classes of damage in each cutting face, but always remained in statistical control.

A novel method is presented to design the configuration of pumping lasers of Raman amplifiers using a multi-objective particle swarm optimizer. The goal is to obtain the pump laser wavelengths and powers that maximize the amplifier on-off gain, while maintaining the flatness of the gain over the used bandwidth. We used an algorithm called Multiple Objective Particle Swarm Optimization with Crowding Distance and Roulette Wheel to generate the non-dominated solutions, considering the average on-off gain and the ripple of the amplifier over the transmission bandwidth as the objectives in the optimization process. We designed amplifiers using three, four and five pump lasers. The experimental results showed that our proposal was able to design Raman amplifiers with a gain ripple lower than 0.2 dB and with an average on-off gain around 16.7 dB, when 20 signal channels and a total pump power of 1 W were considered. Moreover, we demonstrated that it is possible to allow the decision maker to choose among many possible non-dominated solutions depending on the application requirements.